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Diffstat (limited to 'boehm-gc/os_dep.c')
| -rw-r--r-- | boehm-gc/os_dep.c | 4294 |
1 files changed, 4294 insertions, 0 deletions
diff --git a/boehm-gc/os_dep.c b/boehm-gc/os_dep.c new file mode 100644 index 000000000..ca8be1a82 --- /dev/null +++ b/boehm-gc/os_dep.c @@ -0,0 +1,4294 @@ +/* + * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers + * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. + * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved. + * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved. + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program + * for any purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is granted, + * provided the above notices are retained, and a notice that the code was + * modified is included with the above copyright notice. + */ + +# include "private/gc_priv.h" + +# if defined(LINUX) && !defined(POWERPC) +# include <linux/version.h> +# if (LINUX_VERSION_CODE <= 0x10400) + /* Ugly hack to get struct sigcontext_struct definition. Required */ + /* for some early 1.3.X releases. Will hopefully go away soon. */ + /* in some later Linux releases, asm/sigcontext.h may have to */ + /* be included instead. */ +# define __KERNEL__ +# include <asm/signal.h> +# undef __KERNEL__ +# else + /* Kernels prior to 2.1.1 defined struct sigcontext_struct instead of */ + /* struct sigcontext. libc6 (glibc2) uses "struct sigcontext" in */ + /* prototypes, so we have to include the top-level sigcontext.h to */ + /* make sure the former gets defined to be the latter if appropriate. */ +# include <features.h> +# if 2 <= __GLIBC__ +# if 2 == __GLIBC__ && 0 == __GLIBC_MINOR__ + /* glibc 2.1 no longer has sigcontext.h. But signal.h */ + /* has the right declaration for glibc 2.1. */ +# include <sigcontext.h> +# endif /* 0 == __GLIBC_MINOR__ */ +# else /* not 2 <= __GLIBC__ */ + /* libc5 doesn't have <sigcontext.h>: go directly with the kernel */ + /* one. Check LINUX_VERSION_CODE to see which we should reference. */ +# include <asm/sigcontext.h> +# endif /* 2 <= __GLIBC__ */ +# endif +# endif +# if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MACOS) \ + && !defined(MSWINCE) +# include <sys/types.h> +# if !defined(MSWIN32) && !defined(SUNOS4) +# include <unistd.h> +# endif +# endif + +# include <stdio.h> +# if defined(MSWINCE) +# define SIGSEGV 0 /* value is irrelevant */ +# else +# include <signal.h> +# endif + +#if defined(LINUX) || defined(LINUX_STACKBOTTOM) +# include <ctype.h> +#endif + +/* Blatantly OS dependent routines, except for those that are related */ +/* to dynamic loading. */ + +# if defined(HEURISTIC2) || defined(SEARCH_FOR_DATA_START) +# define NEED_FIND_LIMIT +# endif + +# if !defined(STACKBOTTOM) && defined(HEURISTIC2) +# define NEED_FIND_LIMIT +# endif + +# if (defined(SUNOS4) && defined(DYNAMIC_LOADING)) && !defined(PCR) +# define NEED_FIND_LIMIT +# endif + +# if (defined(SVR4) || defined(AUX) || defined(DGUX) \ + || (defined(LINUX) && defined(SPARC))) && !defined(PCR) +# define NEED_FIND_LIMIT +# endif + +#if defined(FREEBSD) && (defined(I386) || defined(X86_64) || defined(powerpc) || defined(__powerpc__)) +# include <machine/trap.h> +# if !defined(PCR) +# define NEED_FIND_LIMIT +# endif +#endif + +#if (defined(NETBSD) || defined(OPENBSD)) && defined(__ELF__) \ + && !defined(NEED_FIND_LIMIT) + /* Used by GC_init_netbsd_elf() below. */ +# define NEED_FIND_LIMIT +#endif + +#ifdef NEED_FIND_LIMIT +# include <setjmp.h> +#endif + +#ifdef AMIGA +# define GC_AMIGA_DEF +# include "AmigaOS.c" +# undef GC_AMIGA_DEF +#endif + +#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) +# define WIN32_LEAN_AND_MEAN +# define NOSERVICE +# include <windows.h> +#endif + +#ifdef MACOS +# include <Processes.h> +#endif + +#ifdef IRIX5 +# include <sys/uio.h> +# include <malloc.h> /* for locking */ +#endif +#if defined(USE_MMAP) || defined(USE_MUNMAP) +# ifndef USE_MMAP + --> USE_MUNMAP requires USE_MMAP +# endif +# include <sys/types.h> +# include <sys/mman.h> +# include <sys/stat.h> +# include <errno.h> +#endif + +#ifdef UNIX_LIKE +# include <fcntl.h> +# if defined(SUNOS5SIGS) && !defined(FREEBSD) +# include <sys/siginfo.h> +# endif + /* Define SETJMP and friends to be the version that restores */ + /* the signal mask. */ +# define SETJMP(env) sigsetjmp(env, 1) +# define LONGJMP(env, val) siglongjmp(env, val) +# define JMP_BUF sigjmp_buf +#else +# define SETJMP(env) setjmp(env) +# define LONGJMP(env, val) longjmp(env, val) +# define JMP_BUF jmp_buf +#endif + +#ifdef DARWIN +/* for get_etext and friends */ +#include <mach-o/getsect.h> +#endif + +#ifdef DJGPP + /* Apparently necessary for djgpp 2.01. May cause problems with */ + /* other versions. */ + typedef long unsigned int caddr_t; +#endif + +#ifdef PCR +# include "il/PCR_IL.h" +# include "th/PCR_ThCtl.h" +# include "mm/PCR_MM.h" +#endif + +#if !defined(NO_EXECUTE_PERMISSION) +# define OPT_PROT_EXEC PROT_EXEC +#else +# define OPT_PROT_EXEC 0 +#endif + +#if defined(LINUX) && \ + (defined(USE_PROC_FOR_LIBRARIES) || defined(IA64) || !defined(SMALL_CONFIG)) + +/* We need to parse /proc/self/maps, either to find dynamic libraries, */ +/* and/or to find the register backing store base (IA64). Do it once */ +/* here. */ + +#define READ read + +/* Repeatedly perform a read call until the buffer is filled or */ +/* we encounter EOF. */ +ssize_t GC_repeat_read(int fd, char *buf, size_t count) +{ + ssize_t num_read = 0; + ssize_t result; + + while (num_read < count) { + result = READ(fd, buf + num_read, count - num_read); + if (result < 0) return result; + if (result == 0) break; + num_read += result; + } + return num_read; +} + +/* + * Apply fn to a buffer containing the contents of /proc/self/maps. + * Return the result of fn or, if we failed, 0. + * We currently do nothing to /proc/self/maps other than simply read + * it. This code could be simplified if we could determine its size + * ahead of time. + */ + +word GC_apply_to_maps(word (*fn)(char *)) +{ + int f; + int result; + size_t maps_size = 4000; /* Initial guess. */ + static char init_buf[1]; + static char *maps_buf = init_buf; + static size_t maps_buf_sz = 1; + + /* Read /proc/self/maps, growing maps_buf as necessary. */ + /* Note that we may not allocate conventionally, and */ + /* thus can't use stdio. */ + do { + if (maps_size >= maps_buf_sz) { + /* Grow only by powers of 2, since we leak "too small" buffers. */ + while (maps_size >= maps_buf_sz) maps_buf_sz *= 2; + maps_buf = GC_scratch_alloc(maps_buf_sz); + if (maps_buf == 0) return 0; + } + f = open("/proc/self/maps", O_RDONLY); + if (-1 == f) return 0; + maps_size = 0; + do { + result = GC_repeat_read(f, maps_buf, maps_buf_sz-1); + if (result <= 0) return 0; + maps_size += result; + } while (result == maps_buf_sz-1); + close(f); + } while (maps_size >= maps_buf_sz); + maps_buf[maps_size] = '\0'; + + /* Apply fn to result. */ + return fn(maps_buf); +} + +#endif /* Need GC_apply_to_maps */ + +#if defined(LINUX) && (defined(USE_PROC_FOR_LIBRARIES) || defined(IA64)) +// +// GC_parse_map_entry parses an entry from /proc/self/maps so we can +// locate all writable data segments that belong to shared libraries. +// The format of one of these entries and the fields we care about +// is as follows: +// XXXXXXXX-XXXXXXXX r-xp 00000000 30:05 260537 name of mapping...\n +// ^^^^^^^^ ^^^^^^^^ ^^^^ ^^ +// start end prot maj_dev +// +// Note that since about auguat 2003 kernels, the columns no longer have +// fixed offsets on 64-bit kernels. Hence we no longer rely on fixed offsets +// anywhere, which is safer anyway. +// + +/* + * Assign various fields of the first line in buf_ptr to *start, *end, + * *prot_buf and *maj_dev. Only *prot_buf may be set for unwritable maps. + */ +char *GC_parse_map_entry(char *buf_ptr, word *start, word *end, + char *prot_buf, unsigned int *maj_dev) +{ + char *start_start, *end_start, *prot_start, *maj_dev_start; + char *p; + char *endp; + + if (buf_ptr == NULL || *buf_ptr == '\0') { + return NULL; + } + + p = buf_ptr; + while (isspace(*p)) ++p; + start_start = p; + GC_ASSERT(isxdigit(*start_start)); + *start = strtoul(start_start, &endp, 16); p = endp; + GC_ASSERT(*p=='-'); + + ++p; + end_start = p; + GC_ASSERT(isxdigit(*end_start)); + *end = strtoul(end_start, &endp, 16); p = endp; + GC_ASSERT(isspace(*p)); + + while (isspace(*p)) ++p; + prot_start = p; + GC_ASSERT(*prot_start == 'r' || *prot_start == '-'); + memcpy(prot_buf, prot_start, 4); + prot_buf[4] = '\0'; + if (prot_buf[1] == 'w') {/* we can skip the rest if it's not writable. */ + /* Skip past protection field to offset field */ + while (!isspace(*p)) ++p; while (isspace(*p)) ++p; + GC_ASSERT(isxdigit(*p)); + /* Skip past offset field, which we ignore */ + while (!isspace(*p)) ++p; while (isspace(*p)) ++p; + maj_dev_start = p; + GC_ASSERT(isxdigit(*maj_dev_start)); + *maj_dev = strtoul(maj_dev_start, NULL, 16); + } + + while (*p && *p++ != '\n'); + + return p; +} + +#endif /* Need to parse /proc/self/maps. */ + +#if defined(SEARCH_FOR_DATA_START) + /* The I386 case can be handled without a search. The Alpha case */ + /* used to be handled differently as well, but the rules changed */ + /* for recent Linux versions. This seems to be the easiest way to */ + /* cover all versions. */ + +# ifdef LINUX + /* Some Linux distributions arrange to define __data_start. Some */ + /* define data_start as a weak symbol. The latter is technically */ + /* broken, since the user program may define data_start, in which */ + /* case we lose. Nonetheless, we try both, prefering __data_start. */ + /* We assume gcc-compatible pragmas. */ +# pragma weak __data_start + extern int __data_start[]; +# pragma weak data_start + extern int data_start[]; +# endif /* LINUX */ + extern int _end[]; + + ptr_t GC_data_start; + + void GC_init_linux_data_start() + { + extern ptr_t GC_find_limit(); + +# ifdef LINUX + /* Try the easy approaches first: */ + if ((ptr_t)__data_start != 0) { + GC_data_start = (ptr_t)(__data_start); + return; + } + if ((ptr_t)data_start != 0) { + GC_data_start = (ptr_t)(data_start); + return; + } +# endif /* LINUX */ + GC_data_start = GC_find_limit((ptr_t)(_end), FALSE); + } +#endif + +# ifdef ECOS + +# ifndef ECOS_GC_MEMORY_SIZE +# define ECOS_GC_MEMORY_SIZE (448 * 1024) +# endif /* ECOS_GC_MEMORY_SIZE */ + +// setjmp() function, as described in ANSI para 7.6.1.1 +#undef SETJMP +#define SETJMP( __env__ ) hal_setjmp( __env__ ) + +// FIXME: This is a simple way of allocating memory which is +// compatible with ECOS early releases. Later releases use a more +// sophisticated means of allocating memory than this simple static +// allocator, but this method is at least bound to work. +static char memory[ECOS_GC_MEMORY_SIZE]; +static char *brk = memory; + +static void *tiny_sbrk(ptrdiff_t increment) +{ + void *p = brk; + + brk += increment; + + if (brk > memory + sizeof memory) + { + brk -= increment; + return NULL; + } + + return p; +} +#define sbrk tiny_sbrk +# endif /* ECOS */ + +#if (defined(NETBSD) || defined(OPENBSD)) && defined(__ELF__) + ptr_t GC_data_start; + + void GC_init_netbsd_elf() + { + extern ptr_t GC_find_limit(); + extern char **environ; + /* This may need to be environ, without the underscore, for */ + /* some versions. */ + GC_data_start = GC_find_limit((ptr_t)&environ, FALSE); + } +#endif + +# ifdef OS2 + +# include <stddef.h> + +# if !defined(__IBMC__) && !defined(__WATCOMC__) /* e.g. EMX */ + +struct exe_hdr { + unsigned short magic_number; + unsigned short padding[29]; + long new_exe_offset; +}; + +#define E_MAGIC(x) (x).magic_number +#define EMAGIC 0x5A4D +#define E_LFANEW(x) (x).new_exe_offset + +struct e32_exe { + unsigned char magic_number[2]; + unsigned char byte_order; + unsigned char word_order; + unsigned long exe_format_level; + unsigned short cpu; + unsigned short os; + unsigned long padding1[13]; + unsigned long object_table_offset; + unsigned long object_count; + unsigned long padding2[31]; +}; + +#define E32_MAGIC1(x) (x).magic_number[0] +#define E32MAGIC1 'L' +#define E32_MAGIC2(x) (x).magic_number[1] +#define E32MAGIC2 'X' +#define E32_BORDER(x) (x).byte_order +#define E32LEBO 0 +#define E32_WORDER(x) (x).word_order +#define E32LEWO 0 +#define E32_CPU(x) (x).cpu +#define E32CPU286 1 +#define E32_OBJTAB(x) (x).object_table_offset +#define E32_OBJCNT(x) (x).object_count + +struct o32_obj { + unsigned long size; + unsigned long base; + unsigned long flags; + unsigned long pagemap; + unsigned long mapsize; + unsigned long reserved; +}; + +#define O32_FLAGS(x) (x).flags +#define OBJREAD 0x0001L +#define OBJWRITE 0x0002L +#define OBJINVALID 0x0080L +#define O32_SIZE(x) (x).size +#define O32_BASE(x) (x).base + +# else /* IBM's compiler */ + +/* A kludge to get around what appears to be a header file bug */ +# ifndef WORD +# define WORD unsigned short +# endif +# ifndef DWORD +# define DWORD unsigned long +# endif + +# define EXE386 1 +# include <newexe.h> +# include <exe386.h> + +# endif /* __IBMC__ */ + +# define INCL_DOSEXCEPTIONS +# define INCL_DOSPROCESS +# define INCL_DOSERRORS +# define INCL_DOSMODULEMGR +# define INCL_DOSMEMMGR +# include <os2.h> + + +/* Disable and enable signals during nontrivial allocations */ + +void GC_disable_signals(void) +{ + ULONG nest; + + DosEnterMustComplete(&nest); + if (nest != 1) ABORT("nested GC_disable_signals"); +} + +void GC_enable_signals(void) +{ + ULONG nest; + + DosExitMustComplete(&nest); + if (nest != 0) ABORT("GC_enable_signals"); +} + + +# else + +# if !defined(PCR) && !defined(AMIGA) && !defined(MSWIN32) \ + && !defined(MSWINCE) \ + && !defined(MACOS) && !defined(DJGPP) && !defined(DOS4GW) \ + && !defined(NOSYS) && !defined(ECOS) + +# if defined(SIG_BLOCK) + /* Use POSIX/SYSV interface */ +# define SIGSET_T sigset_t +# define SIG_DEL(set, signal) sigdelset(&(set), (signal)) +# define SIG_FILL(set) sigfillset(&set) +# define SIGSETMASK(old, new) sigprocmask(SIG_SETMASK, &(new), &(old)) +# elif defined(sigmask) && !defined(UTS4) && !defined(HURD) + /* Use the traditional BSD interface */ +# define SIGSET_T int +# define SIG_DEL(set, signal) (set) &= ~(sigmask(signal)) +# define SIG_FILL(set) (set) = 0x7fffffff + /* Setting the leading bit appears to provoke a bug in some */ + /* longjmp implementations. Most systems appear not to have */ + /* a signal 32. */ +# define SIGSETMASK(old, new) (old) = sigsetmask(new) +# else +# error undetectable signal API +# endif + +static GC_bool mask_initialized = FALSE; + +static SIGSET_T new_mask; + +static SIGSET_T old_mask; + +static SIGSET_T dummy; + +#if defined(PRINTSTATS) && !defined(THREADS) +# define CHECK_SIGNALS + int GC_sig_disabled = 0; +#endif + +void GC_disable_signals() +{ + if (!mask_initialized) { + SIG_FILL(new_mask); + + SIG_DEL(new_mask, SIGSEGV); + SIG_DEL(new_mask, SIGILL); + SIG_DEL(new_mask, SIGQUIT); +# ifdef SIGBUS + SIG_DEL(new_mask, SIGBUS); +# endif +# ifdef SIGIOT + SIG_DEL(new_mask, SIGIOT); +# endif +# ifdef SIGEMT + SIG_DEL(new_mask, SIGEMT); +# endif +# ifdef SIGTRAP + SIG_DEL(new_mask, SIGTRAP); +# endif + mask_initialized = TRUE; + } +# ifdef CHECK_SIGNALS + if (GC_sig_disabled != 0) ABORT("Nested disables"); + GC_sig_disabled++; +# endif + SIGSETMASK(old_mask,new_mask); +} + +void GC_enable_signals() +{ +# ifdef CHECK_SIGNALS + if (GC_sig_disabled != 1) ABORT("Unmatched enable"); + GC_sig_disabled--; +# endif + SIGSETMASK(dummy,old_mask); +} + +# endif /* !PCR */ + +# endif /*!OS/2 */ + +/* Ivan Demakov: simplest way (to me) */ +#if defined (DOS4GW) + void GC_disable_signals() { } + void GC_enable_signals() { } +#endif + +/* Find the page size */ +word GC_page_size; + +# if defined(MSWIN32) || defined(MSWINCE) || defined (CYGWIN32) + void GC_setpagesize() + { + GetSystemInfo(&GC_sysinfo); + GC_page_size = GC_sysinfo.dwPageSize; + } + +# else +# if defined(MPROTECT_VDB) || defined(PROC_VDB) || defined(USE_MMAP) \ + || defined(USE_MUNMAP) + void GC_setpagesize() + { + GC_page_size = GETPAGESIZE(); + } +# else + /* It's acceptable to fake it. */ + void GC_setpagesize() + { + GC_page_size = HBLKSIZE; + } +# endif +# endif + +/* + * Find the base of the stack. + * Used only in single-threaded environment. + * With threads, GC_mark_roots needs to know how to do this. + * Called with allocator lock held. + */ +# if defined(MSWIN32) || defined(MSWINCE) +# define is_writable(prot) ((prot) == PAGE_READWRITE \ + || (prot) == PAGE_WRITECOPY \ + || (prot) == PAGE_EXECUTE_READWRITE \ + || (prot) == PAGE_EXECUTE_WRITECOPY) +/* Return the number of bytes that are writable starting at p. */ +/* The pointer p is assumed to be page aligned. */ +/* If base is not 0, *base becomes the beginning of the */ +/* allocation region containing p. */ +word GC_get_writable_length(ptr_t p, ptr_t *base) +{ + MEMORY_BASIC_INFORMATION buf; + word result; + word protect; + + result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf)) ABORT("Weird VirtualQuery result"); + if (base != 0) *base = (ptr_t)(buf.AllocationBase); + protect = (buf.Protect & ~(PAGE_GUARD | PAGE_NOCACHE)); + if (!is_writable(protect)) { + return(0); + } + if (buf.State != MEM_COMMIT) return(0); + return(buf.RegionSize); +} + +ptr_t GC_get_stack_base() +{ + int dummy; + ptr_t sp = (ptr_t)(&dummy); + ptr_t trunc_sp = (ptr_t)((word)sp & ~(GC_page_size - 1)); + word size = GC_get_writable_length(trunc_sp, 0); + + return(trunc_sp + size); +} + + +# endif /* MS Windows */ + +# ifdef BEOS +# include <kernel/OS.h> +ptr_t GC_get_stack_base(){ + thread_info th; + get_thread_info(find_thread(NULL),&th); + return th.stack_end; +} +# endif /* BEOS */ + + +# ifdef OS2 + +ptr_t GC_get_stack_base() +{ + PTIB ptib; + PPIB ppib; + + if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) { + GC_err_printf0("DosGetInfoBlocks failed\n"); + ABORT("DosGetInfoBlocks failed\n"); + } + return((ptr_t)(ptib -> tib_pstacklimit)); +} + +# endif /* OS2 */ + +# ifdef AMIGA +# define GC_AMIGA_SB +# include "AmigaOS.c" +# undef GC_AMIGA_SB +# endif /* AMIGA */ + +# if defined(NEED_FIND_LIMIT) || defined(UNIX_LIKE) + +# ifdef __STDC__ + typedef void (*handler)(int); +# else + typedef void (*handler)(); +# endif + +# if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1) \ + || defined(HURD) || defined(NETBSD) + static struct sigaction old_segv_act; +# if defined(IRIX5) || defined(HPUX) \ + || defined(HURD) || defined(NETBSD) + static struct sigaction old_bus_act; +# endif +# else + static handler old_segv_handler, old_bus_handler; +# endif + +# ifdef __STDC__ + void GC_set_and_save_fault_handler(handler h) +# else + void GC_set_and_save_fault_handler(h) + handler h; +# endif + { +# if defined(SUNOS5SIGS) || defined(IRIX5) \ + || defined(OSF1) || defined(HURD) || defined(NETBSD) + struct sigaction act; + + act.sa_handler = h; +# if 0 /* Was necessary for Solaris 2.3 and very temporary */ + /* NetBSD bugs. */ + act.sa_flags = SA_RESTART | SA_NODEFER; +# else + act.sa_flags = SA_RESTART; +# endif + + (void) sigemptyset(&act.sa_mask); +# ifdef GC_IRIX_THREADS + /* Older versions have a bug related to retrieving and */ + /* and setting a handler at the same time. */ + (void) sigaction(SIGSEGV, 0, &old_segv_act); + (void) sigaction(SIGSEGV, &act, 0); + (void) sigaction(SIGBUS, 0, &old_bus_act); + (void) sigaction(SIGBUS, &act, 0); +# else + (void) sigaction(SIGSEGV, &act, &old_segv_act); +# if defined(IRIX5) \ + || defined(HPUX) || defined(HURD) || defined(NETBSD) + /* Under Irix 5.x or HP/UX, we may get SIGBUS. */ + /* Pthreads doesn't exist under Irix 5.x, so we */ + /* don't have to worry in the threads case. */ + (void) sigaction(SIGBUS, &act, &old_bus_act); +# endif +# endif /* GC_IRIX_THREADS */ +# else + old_segv_handler = signal(SIGSEGV, h); +# ifdef SIGBUS + old_bus_handler = signal(SIGBUS, h); +# endif +# endif + } +# endif /* NEED_FIND_LIMIT || UNIX_LIKE */ + +# ifdef NEED_FIND_LIMIT + /* Some tools to implement HEURISTIC2 */ +# define MIN_PAGE_SIZE 256 /* Smallest conceivable page size, bytes */ + /* static */ JMP_BUF GC_jmp_buf; + + /*ARGSUSED*/ + void GC_fault_handler(sig) + int sig; + { + LONGJMP(GC_jmp_buf, 1); + } + + void GC_setup_temporary_fault_handler() + { + GC_set_and_save_fault_handler(GC_fault_handler); + } + + void GC_reset_fault_handler() + { +# if defined(SUNOS5SIGS) || defined(IRIX5) \ + || defined(OSF1) || defined(HURD) || defined(NETBSD) + (void) sigaction(SIGSEGV, &old_segv_act, 0); +# if defined(IRIX5) \ + || defined(HPUX) || defined(HURD) || defined(NETBSD) + (void) sigaction(SIGBUS, &old_bus_act, 0); +# endif +# else + (void) signal(SIGSEGV, old_segv_handler); +# ifdef SIGBUS + (void) signal(SIGBUS, old_bus_handler); +# endif +# endif + } + + /* Return the first nonaddressible location > p (up) or */ + /* the smallest location q s.t. [q,p) is addressable (!up). */ + /* We assume that p (up) or p-1 (!up) is addressable. */ + ptr_t GC_find_limit(p, up) + ptr_t p; + GC_bool up; + { + static VOLATILE ptr_t result; + /* Needs to be static, since otherwise it may not be */ + /* preserved across the longjmp. Can safely be */ + /* static since it's only called once, with the */ + /* allocation lock held. */ + + + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + result = (ptr_t)(((word)(p)) + & ~(MIN_PAGE_SIZE-1)); + for (;;) { + if (up) { + result += MIN_PAGE_SIZE; + } else { + result -= MIN_PAGE_SIZE; + } + GC_noop1((word)(*result)); + } + } + GC_reset_fault_handler(); + if (!up) { + result += MIN_PAGE_SIZE; + } + return(result); + } +# endif + +#if defined(ECOS) || defined(NOSYS) + ptr_t GC_get_stack_base() + { + return STACKBOTTOM; + } +#endif + +#ifdef HPUX_STACKBOTTOM + +#include <sys/param.h> +#include <sys/pstat.h> + + ptr_t GC_get_register_stack_base(void) + { + struct pst_vm_status vm_status; + + int i = 0; + while (pstat_getprocvm(&vm_status, sizeof(vm_status), 0, i++) == 1) { + if (vm_status.pst_type == PS_RSESTACK) { + return (ptr_t) vm_status.pst_vaddr; + } + } + + /* old way to get the register stackbottom */ + return (ptr_t)(((word)GC_stackbottom - BACKING_STORE_DISPLACEMENT - 1) + & ~(BACKING_STORE_ALIGNMENT - 1)); + } + +#endif /* HPUX_STACK_BOTTOM */ + +#ifdef LINUX_STACKBOTTOM + +#include <sys/types.h> +#include <sys/stat.h> + +# define STAT_SKIP 27 /* Number of fields preceding startstack */ + /* field in /proc/self/stat */ + +#ifdef USE_LIBC_PRIVATES +# pragma weak __libc_stack_end + extern ptr_t __libc_stack_end; +#endif + +# ifdef IA64 + /* Try to read the backing store base from /proc/self/maps. */ + /* We look for the writable mapping with a 0 major device, */ + /* which is as close to our frame as possible, but below it.*/ + static word backing_store_base_from_maps(char *maps) + { + char prot_buf[5]; + char *buf_ptr = maps; + word start, end; + unsigned int maj_dev; + word current_best = 0; + word dummy; + + for (;;) { + buf_ptr = GC_parse_map_entry(buf_ptr, &start, &end, prot_buf, &maj_dev); + if (buf_ptr == NULL) return current_best; + if (prot_buf[1] == 'w' && maj_dev == 0) { + if (end < (word)(&dummy) && start > current_best) current_best = start; + } + } + return current_best; + } + + static word backing_store_base_from_proc(void) + { + return GC_apply_to_maps(backing_store_base_from_maps); + } + +# ifdef USE_LIBC_PRIVATES +# pragma weak __libc_ia64_register_backing_store_base + extern ptr_t __libc_ia64_register_backing_store_base; +# endif + + ptr_t GC_get_register_stack_base(void) + { +# ifdef USE_LIBC_PRIVATES + if (0 != &__libc_ia64_register_backing_store_base + && 0 != __libc_ia64_register_backing_store_base) { + /* Glibc 2.2.4 has a bug such that for dynamically linked */ + /* executables __libc_ia64_register_backing_store_base is */ + /* defined but uninitialized during constructor calls. */ + /* Hence we check for both nonzero address and value. */ + return __libc_ia64_register_backing_store_base; + } +# endif + word result = backing_store_base_from_proc(); + if (0 == result) { + /* Use dumb heuristics. Works only for default configuration. */ + result = (word)GC_stackbottom - BACKING_STORE_DISPLACEMENT; + result += BACKING_STORE_ALIGNMENT - 1; + result &= ~(BACKING_STORE_ALIGNMENT - 1); + /* Verify that it's at least readable. If not, we goofed. */ + GC_noop1(*(word *)result); + } + return (ptr_t)result; + } +# endif + + ptr_t GC_linux_stack_base(void) + { + /* We read the stack base value from /proc/self/stat. We do this */ + /* using direct I/O system calls in order to avoid calling malloc */ + /* in case REDIRECT_MALLOC is defined. */ +# define STAT_BUF_SIZE 4096 +# define STAT_READ read + /* Should probably call the real read, if read is wrapped. */ + char stat_buf[STAT_BUF_SIZE]; + int f; + char c; + word result = 0; + size_t i, buf_offset = 0; + + /* First try the easy way. This should work for glibc 2.2 */ + /* This fails in a prelinked ("prelink" command) executable */ + /* since the correct value of __libc_stack_end never */ + /* becomes visible to us. The second test works around */ + /* this. */ +# ifdef USE_LIBC_PRIVATES + if (0 != &__libc_stack_end && 0 != __libc_stack_end ) { +# ifdef IA64 + /* Some versions of glibc set the address 16 bytes too */ + /* low while the initialization code is running. */ + if (((word)__libc_stack_end & 0xfff) + 0x10 < 0x1000) { + return __libc_stack_end + 0x10; + } /* Otherwise it's not safe to add 16 bytes and we fall */ + /* back to using /proc. */ +# else +# ifdef SPARC + /* Older versions of glibc for 64-bit Sparc do not set + * this variable correctly, it gets set to either zero + * or one. + */ + if (__libc_stack_end != (ptr_t) (unsigned long)0x1) + return __libc_stack_end; +# else + return __libc_stack_end; +# endif +# endif + } +# endif + f = open("/proc/self/stat", O_RDONLY); + if (f < 0 || STAT_READ(f, stat_buf, STAT_BUF_SIZE) < 2 * STAT_SKIP) { + ABORT("Couldn't read /proc/self/stat"); + } + c = stat_buf[buf_offset++]; + /* Skip the required number of fields. This number is hopefully */ + /* constant across all Linux implementations. */ + for (i = 0; i < STAT_SKIP; ++i) { + while (isspace(c)) c = stat_buf[buf_offset++]; + while (!isspace(c)) c = stat_buf[buf_offset++]; + } + while (isspace(c)) c = stat_buf[buf_offset++]; + while (isdigit(c)) { + result *= 10; + result += c - '0'; + c = stat_buf[buf_offset++]; + } + close(f); + if (result < 0x10000000) ABORT("Absurd stack bottom value"); + return (ptr_t)result; + } + +#endif /* LINUX_STACKBOTTOM */ + +#ifdef FREEBSD_STACKBOTTOM + +/* This uses an undocumented sysctl call, but at least one expert */ +/* believes it will stay. */ + +#include <unistd.h> +#include <sys/types.h> +#include <sys/sysctl.h> + + ptr_t GC_freebsd_stack_base(void) + { + int nm[2] = {CTL_KERN, KERN_USRSTACK}; + ptr_t base; + size_t len = sizeof(ptr_t); + int r = sysctl(nm, 2, &base, &len, NULL, 0); + + if (r) ABORT("Error getting stack base"); + + return base; + } + +#endif /* FREEBSD_STACKBOTTOM */ + +#if !defined(BEOS) && !defined(AMIGA) && !defined(MSWIN32) \ + && !defined(MSWINCE) && !defined(OS2) && !defined(NOSYS) && !defined(ECOS) + +ptr_t GC_get_stack_base() +{ +# if defined(HEURISTIC1) || defined(HEURISTIC2) || \ + defined(LINUX_STACKBOTTOM) || defined(FREEBSD_STACKBOTTOM) + word dummy; + ptr_t result; +# endif + +# define STACKBOTTOM_ALIGNMENT_M1 ((word)STACK_GRAN - 1) + +# ifdef STACKBOTTOM + return(STACKBOTTOM); +# else +# ifdef HEURISTIC1 +# ifdef STACK_GROWS_DOWN + result = (ptr_t)((((word)(&dummy)) + + STACKBOTTOM_ALIGNMENT_M1) + & ~STACKBOTTOM_ALIGNMENT_M1); +# else + result = (ptr_t)(((word)(&dummy)) + & ~STACKBOTTOM_ALIGNMENT_M1); +# endif +# endif /* HEURISTIC1 */ +# ifdef LINUX_STACKBOTTOM + result = GC_linux_stack_base(); +# endif +# ifdef FREEBSD_STACKBOTTOM + result = GC_freebsd_stack_base(); +# endif +# ifdef HEURISTIC2 +# ifdef STACK_GROWS_DOWN + result = GC_find_limit((ptr_t)(&dummy), TRUE); +# ifdef HEURISTIC2_LIMIT + if (result > HEURISTIC2_LIMIT + && (ptr_t)(&dummy) < HEURISTIC2_LIMIT) { + result = HEURISTIC2_LIMIT; + } +# endif +# else + result = GC_find_limit((ptr_t)(&dummy), FALSE); +# ifdef HEURISTIC2_LIMIT + if (result < HEURISTIC2_LIMIT + && (ptr_t)(&dummy) > HEURISTIC2_LIMIT) { + result = HEURISTIC2_LIMIT; + } +# endif +# endif + +# endif /* HEURISTIC2 */ +# ifdef STACK_GROWS_DOWN + if (result == 0) result = (ptr_t)(signed_word)(-sizeof(ptr_t)); +# endif + return(result); +# endif /* STACKBOTTOM */ +} + +# endif /* ! AMIGA, !OS 2, ! MS Windows, !BEOS, !NOSYS, !ECOS */ + +/* + * Register static data segment(s) as roots. + * If more data segments are added later then they need to be registered + * add that point (as we do with SunOS dynamic loading), + * or GC_mark_roots needs to check for them (as we do with PCR). + * Called with allocator lock held. + */ + +# ifdef OS2 + +void GC_register_data_segments() +{ + PTIB ptib; + PPIB ppib; + HMODULE module_handle; +# define PBUFSIZ 512 + UCHAR path[PBUFSIZ]; + FILE * myexefile; + struct exe_hdr hdrdos; /* MSDOS header. */ + struct e32_exe hdr386; /* Real header for my executable */ + struct o32_obj seg; /* Currrent segment */ + int nsegs; + + + if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) { + GC_err_printf0("DosGetInfoBlocks failed\n"); + ABORT("DosGetInfoBlocks failed\n"); + } + module_handle = ppib -> pib_hmte; + if (DosQueryModuleName(module_handle, PBUFSIZ, path) != NO_ERROR) { + GC_err_printf0("DosQueryModuleName failed\n"); + ABORT("DosGetInfoBlocks failed\n"); + } + myexefile = fopen(path, "rb"); + if (myexefile == 0) { + GC_err_puts("Couldn't open executable "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Failed to open executable\n"); + } + if (fread((char *)(&hdrdos), 1, sizeof hdrdos, myexefile) < sizeof hdrdos) { + GC_err_puts("Couldn't read MSDOS header from "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Couldn't read MSDOS header"); + } + if (E_MAGIC(hdrdos) != EMAGIC) { + GC_err_puts("Executable has wrong DOS magic number: "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Bad DOS magic number"); + } + if (fseek(myexefile, E_LFANEW(hdrdos), SEEK_SET) != 0) { + GC_err_puts("Seek to new header failed in "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Bad DOS magic number"); + } + if (fread((char *)(&hdr386), 1, sizeof hdr386, myexefile) < sizeof hdr386) { + GC_err_puts("Couldn't read MSDOS header from "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Couldn't read OS/2 header"); + } + if (E32_MAGIC1(hdr386) != E32MAGIC1 || E32_MAGIC2(hdr386) != E32MAGIC2) { + GC_err_puts("Executable has wrong OS/2 magic number:"); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Bad OS/2 magic number"); + } + if ( E32_BORDER(hdr386) != E32LEBO || E32_WORDER(hdr386) != E32LEWO) { + GC_err_puts("Executable %s has wrong byte order: "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Bad byte order"); + } + if ( E32_CPU(hdr386) == E32CPU286) { + GC_err_puts("GC can't handle 80286 executables: "); + GC_err_puts(path); GC_err_puts("\n"); + EXIT(); + } + if (fseek(myexefile, E_LFANEW(hdrdos) + E32_OBJTAB(hdr386), + SEEK_SET) != 0) { + GC_err_puts("Seek to object table failed: "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Seek to object table failed"); + } + for (nsegs = E32_OBJCNT(hdr386); nsegs > 0; nsegs--) { + int flags; + if (fread((char *)(&seg), 1, sizeof seg, myexefile) < sizeof seg) { + GC_err_puts("Couldn't read obj table entry from "); + GC_err_puts(path); GC_err_puts("\n"); + ABORT("Couldn't read obj table entry"); + } + flags = O32_FLAGS(seg); + if (!(flags & OBJWRITE)) continue; + if (!(flags & OBJREAD)) continue; + if (flags & OBJINVALID) { + GC_err_printf0("Object with invalid pages?\n"); + continue; + } + GC_add_roots_inner(O32_BASE(seg), O32_BASE(seg)+O32_SIZE(seg), FALSE); + } +} + +# else /* !OS2 */ + +# if defined(MSWIN32) || defined(MSWINCE) || defined (CYGWIN32) + +# ifdef CYGWIN32 +# define GC_no_win32_dlls (FALSE) +# endif + +# ifdef MSWIN32 + /* Unfortunately, we have to handle win32s very differently from NT, */ + /* Since VirtualQuery has very different semantics. In particular, */ + /* under win32s a VirtualQuery call on an unmapped page returns an */ + /* invalid result. Under NT, GC_register_data_segments is a noop and */ + /* all real work is done by GC_register_dynamic_libraries. Under */ + /* win32s, we cannot find the data segments associated with dll's. */ + /* We register the main data segment here. */ + GC_bool GC_no_win32_dlls = FALSE; + /* This used to be set for gcc, to avoid dealing with */ + /* the structured exception handling issues. But we now have */ + /* assembly code to do that right. */ + GC_bool GC_wnt = FALSE; + /* This is a Windows NT derivative, i.e. NT, W2K, XP or later. */ + + void GC_init_win32() + { + /* if we're running under win32s, assume that no DLLs will be loaded */ + DWORD v = GetVersion(); + GC_wnt = !(v & 0x80000000); + GC_no_win32_dlls |= ((!GC_wnt) && (v & 0xff) <= 3); + } + + /* Return the smallest address a such that VirtualQuery */ + /* returns correct results for all addresses between a and start. */ + /* Assumes VirtualQuery returns correct information for start. */ + ptr_t GC_least_described_address(ptr_t start) + { + MEMORY_BASIC_INFORMATION buf; + DWORD result; + LPVOID limit; + ptr_t p; + LPVOID q; + + limit = GC_sysinfo.lpMinimumApplicationAddress; + p = (ptr_t)((word)start & ~(GC_page_size - 1)); + for (;;) { + q = (LPVOID)(p - GC_page_size); + if ((ptr_t)q > (ptr_t)p /* underflow */ || q < limit) break; + result = VirtualQuery(q, &buf, sizeof(buf)); + if (result != sizeof(buf) || buf.AllocationBase == 0) break; + p = (ptr_t)(buf.AllocationBase); + } + return(p); + } +# endif + +# ifndef REDIRECT_MALLOC + /* We maintain a linked list of AllocationBase values that we know */ + /* correspond to malloc heap sections. Currently this is only called */ + /* during a GC. But there is some hope that for long running */ + /* programs we will eventually see most heap sections. */ + + /* In the long run, it would be more reliable to occasionally walk */ + /* the malloc heap with HeapWalk on the default heap. But that */ + /* apparently works only for NT-based Windows. */ + + /* In the long run, a better data structure would also be nice ... */ + struct GC_malloc_heap_list { + void * allocation_base; + struct GC_malloc_heap_list *next; + } *GC_malloc_heap_l = 0; + + /* Is p the base of one of the malloc heap sections we already know */ + /* about? */ + GC_bool GC_is_malloc_heap_base(ptr_t p) + { + struct GC_malloc_heap_list *q = GC_malloc_heap_l; + + while (0 != q) { + if (q -> allocation_base == p) return TRUE; + q = q -> next; + } + return FALSE; + } + + void *GC_get_allocation_base(void *p) + { + MEMORY_BASIC_INFORMATION buf; + DWORD result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf)) { + ABORT("Weird VirtualQuery result"); + } + return buf.AllocationBase; + } + + size_t GC_max_root_size = 100000; /* Appr. largest root size. */ + + void GC_add_current_malloc_heap() + { + struct GC_malloc_heap_list *new_l = + malloc(sizeof(struct GC_malloc_heap_list)); + void * candidate = GC_get_allocation_base(new_l); + + if (new_l == 0) return; + if (GC_is_malloc_heap_base(candidate)) { + /* Try a little harder to find malloc heap. */ + size_t req_size = 10000; + do { + void *p = malloc(req_size); + if (0 == p) { free(new_l); return; } + candidate = GC_get_allocation_base(p); + free(p); + req_size *= 2; + } while (GC_is_malloc_heap_base(candidate) + && req_size < GC_max_root_size/10 && req_size < 500000); + if (GC_is_malloc_heap_base(candidate)) { + free(new_l); return; + } + } +# ifdef CONDPRINT + if (GC_print_stats) + GC_printf1("Found new system malloc AllocationBase at 0x%lx\n", + candidate); +# endif + new_l -> allocation_base = candidate; + new_l -> next = GC_malloc_heap_l; + GC_malloc_heap_l = new_l; + } +# endif /* REDIRECT_MALLOC */ + + /* Is p the start of either the malloc heap, or of one of our */ + /* heap sections? */ + GC_bool GC_is_heap_base (ptr_t p) + { + + unsigned i; + +# ifndef REDIRECT_MALLOC + static word last_gc_no = -1; + + if (last_gc_no != GC_gc_no) { + GC_add_current_malloc_heap(); + last_gc_no = GC_gc_no; + } + if (GC_root_size > GC_max_root_size) GC_max_root_size = GC_root_size; + if (GC_is_malloc_heap_base(p)) return TRUE; +# endif + for (i = 0; i < GC_n_heap_bases; i++) { + if (GC_heap_bases[i] == p) return TRUE; + } + return FALSE ; + } + +# ifdef MSWIN32 + void GC_register_root_section(ptr_t static_root) + { + MEMORY_BASIC_INFORMATION buf; + DWORD result; + DWORD protect; + LPVOID p; + char * base; + char * limit, * new_limit; + + if (!GC_no_win32_dlls) return; + p = base = limit = GC_least_described_address(static_root); + while (p < GC_sysinfo.lpMaximumApplicationAddress) { + result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf) || buf.AllocationBase == 0 + || GC_is_heap_base(buf.AllocationBase)) break; + new_limit = (char *)p + buf.RegionSize; + protect = buf.Protect; + if (buf.State == MEM_COMMIT + && is_writable(protect)) { + if ((char *)p == limit) { + limit = new_limit; + } else { + if (base != limit) GC_add_roots_inner(base, limit, FALSE); + base = p; + limit = new_limit; + } + } + if (p > (LPVOID)new_limit /* overflow */) break; + p = (LPVOID)new_limit; + } + if (base != limit) GC_add_roots_inner(base, limit, FALSE); + } +#endif + + void GC_register_data_segments() + { +# ifdef MSWIN32 + static char dummy; + GC_register_root_section((ptr_t)(&dummy)); +# endif + } + +# else /* !OS2 && !Windows */ + +# if (defined(SVR4) || defined(AUX) || defined(DGUX) \ + || (defined(LINUX) && defined(SPARC))) && !defined(PCR) +ptr_t GC_SysVGetDataStart(max_page_size, etext_addr) +int max_page_size; +int * etext_addr; +{ + word text_end = ((word)(etext_addr) + sizeof(word) - 1) + & ~(sizeof(word) - 1); + /* etext rounded to word boundary */ + word next_page = ((text_end + (word)max_page_size - 1) + & ~((word)max_page_size - 1)); + word page_offset = (text_end & ((word)max_page_size - 1)); + VOLATILE char * result = (char *)(next_page + page_offset); + /* Note that this isnt equivalent to just adding */ + /* max_page_size to &etext if &etext is at a page boundary */ + + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + /* Try writing to the address. */ + *result = *result; + GC_reset_fault_handler(); + } else { + GC_reset_fault_handler(); + /* We got here via a longjmp. The address is not readable. */ + /* This is known to happen under Solaris 2.4 + gcc, which place */ + /* string constants in the text segment, but after etext. */ + /* Use plan B. Note that we now know there is a gap between */ + /* text and data segments, so plan A bought us something. */ + result = (char *)GC_find_limit((ptr_t)(DATAEND), FALSE); + } + return((ptr_t)result); +} +# endif + +# if defined(FREEBSD) && (defined(I386) || defined(X86_64) || defined(powerpc) || defined(__powerpc__)) && !defined(PCR) +/* Its unclear whether this should be identical to the above, or */ +/* whether it should apply to non-X86 architectures. */ +/* For now we don't assume that there is always an empty page after */ +/* etext. But in some cases there actually seems to be slightly more. */ +/* This also deals with holes between read-only data and writable data. */ +ptr_t GC_FreeBSDGetDataStart(max_page_size, etext_addr) +int max_page_size; +int * etext_addr; +{ + word text_end = ((word)(etext_addr) + sizeof(word) - 1) + & ~(sizeof(word) - 1); + /* etext rounded to word boundary */ + VOLATILE word next_page = (text_end + (word)max_page_size - 1) + & ~((word)max_page_size - 1); + VOLATILE ptr_t result = (ptr_t)text_end; + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + /* Try reading at the address. */ + /* This should happen before there is another thread. */ + for (; next_page < (word)(DATAEND); next_page += (word)max_page_size) + *(VOLATILE char *)next_page; + GC_reset_fault_handler(); + } else { + GC_reset_fault_handler(); + /* As above, we go to plan B */ + result = GC_find_limit((ptr_t)(DATAEND), FALSE); + } + return(result); +} + +# endif + + +#ifdef AMIGA + +# define GC_AMIGA_DS +# include "AmigaOS.c" +# undef GC_AMIGA_DS + +#else /* !OS2 && !Windows && !AMIGA */ + +void GC_register_data_segments() +{ +# if !defined(PCR) && !defined(SRC_M3) && !defined(MACOS) +# if defined(REDIRECT_MALLOC) && defined(GC_SOLARIS_THREADS) + /* As of Solaris 2.3, the Solaris threads implementation */ + /* allocates the data structure for the initial thread with */ + /* sbrk at process startup. It needs to be scanned, so that */ + /* we don't lose some malloc allocated data structures */ + /* hanging from it. We're on thin ice here ... */ + extern caddr_t sbrk(); + + GC_add_roots_inner(DATASTART, (char *)sbrk(0), FALSE); +# else + GC_add_roots_inner(DATASTART, (char *)(DATAEND), FALSE); +# if defined(DATASTART2) + GC_add_roots_inner(DATASTART2, (char *)(DATAEND2), FALSE); +# endif +# endif +# endif +# if defined(MACOS) + { +# if defined(THINK_C) + extern void* GC_MacGetDataStart(void); + /* globals begin above stack and end at a5. */ + GC_add_roots_inner((ptr_t)GC_MacGetDataStart(), + (ptr_t)LMGetCurrentA5(), FALSE); +# else +# if defined(__MWERKS__) +# if !__POWERPC__ + extern void* GC_MacGetDataStart(void); + /* MATTHEW: Function to handle Far Globals (CW Pro 3) */ +# if __option(far_data) + extern void* GC_MacGetDataEnd(void); +# endif + /* globals begin above stack and end at a5. */ + GC_add_roots_inner((ptr_t)GC_MacGetDataStart(), + (ptr_t)LMGetCurrentA5(), FALSE); + /* MATTHEW: Handle Far Globals */ +# if __option(far_data) + /* Far globals follow he QD globals: */ + GC_add_roots_inner((ptr_t)LMGetCurrentA5(), + (ptr_t)GC_MacGetDataEnd(), FALSE); +# endif +# else + extern char __data_start__[], __data_end__[]; + GC_add_roots_inner((ptr_t)&__data_start__, + (ptr_t)&__data_end__, FALSE); +# endif /* __POWERPC__ */ +# endif /* __MWERKS__ */ +# endif /* !THINK_C */ + } +# endif /* MACOS */ + + /* Dynamic libraries are added at every collection, since they may */ + /* change. */ +} + +# endif /* ! AMIGA */ +# endif /* ! MSWIN32 && ! MSWINCE*/ +# endif /* ! OS2 */ + +/* + * Auxiliary routines for obtaining memory from OS. + */ + +# if !defined(OS2) && !defined(PCR) && !defined(AMIGA) \ + && !defined(MSWIN32) && !defined(MSWINCE) \ + && !defined(MACOS) && !defined(DOS4GW) + +# ifdef SUNOS4 + extern caddr_t sbrk(); +# endif +# ifdef __STDC__ +# define SBRK_ARG_T ptrdiff_t +# else +# define SBRK_ARG_T int +# endif + + +# if 0 && defined(RS6000) /* We now use mmap */ +/* The compiler seems to generate speculative reads one past the end of */ +/* an allocated object. Hence we need to make sure that the page */ +/* following the last heap page is also mapped. */ +ptr_t GC_unix_get_mem(bytes) +word bytes; +{ + caddr_t cur_brk = (caddr_t)sbrk(0); + caddr_t result; + SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1); + static caddr_t my_brk_val = 0; + + if ((SBRK_ARG_T)bytes < 0) return(0); /* too big */ + if (lsbs != 0) { + if((caddr_t)(sbrk(GC_page_size - lsbs)) == (caddr_t)(-1)) return(0); + } + if (cur_brk == my_brk_val) { + /* Use the extra block we allocated last time. */ + result = (ptr_t)sbrk((SBRK_ARG_T)bytes); + if (result == (caddr_t)(-1)) return(0); + result -= GC_page_size; + } else { + result = (ptr_t)sbrk(GC_page_size + (SBRK_ARG_T)bytes); + if (result == (caddr_t)(-1)) return(0); + } + my_brk_val = result + bytes + GC_page_size; /* Always page aligned */ + return((ptr_t)result); +} + +#else /* Not RS6000 */ + +#if defined(USE_MMAP) || defined(USE_MUNMAP) + +#ifdef USE_MMAP_FIXED +# define GC_MMAP_FLAGS MAP_FIXED | MAP_PRIVATE + /* Seems to yield better performance on Solaris 2, but can */ + /* be unreliable if something is already mapped at the address. */ +#else +# define GC_MMAP_FLAGS MAP_PRIVATE +#endif + +#ifdef USE_MMAP_ANON +# define zero_fd -1 +# if defined(MAP_ANONYMOUS) +# define OPT_MAP_ANON MAP_ANONYMOUS +# else +# define OPT_MAP_ANON MAP_ANON +# endif +#else + static int zero_fd; +# define OPT_MAP_ANON 0 +#endif + +#endif /* defined(USE_MMAP) || defined(USE_MUNMAP) */ + +#if defined(USE_MMAP) +/* Tested only under Linux, IRIX5 and Solaris 2 */ + +#ifndef HEAP_START +# define HEAP_START 0 +#endif + +ptr_t GC_unix_get_mem(bytes) +word bytes; +{ + void *result; + static ptr_t last_addr = HEAP_START; + +# ifndef USE_MMAP_ANON + static GC_bool initialized = FALSE; + + if (!initialized) { + zero_fd = open("/dev/zero", O_RDONLY); + fcntl(zero_fd, F_SETFD, FD_CLOEXEC); + initialized = TRUE; + } +# endif + + if (bytes & (GC_page_size -1)) ABORT("Bad GET_MEM arg"); + result = mmap(last_addr, bytes, PROT_READ | PROT_WRITE | OPT_PROT_EXEC, + GC_MMAP_FLAGS | OPT_MAP_ANON, zero_fd, 0/* offset */); + if (result == MAP_FAILED) return(0); + last_addr = (ptr_t)result + bytes + GC_page_size - 1; + last_addr = (ptr_t)((word)last_addr & ~(GC_page_size - 1)); +# if !defined(LINUX) + if (last_addr == 0) { + /* Oops. We got the end of the address space. This isn't */ + /* usable by arbitrary C code, since one-past-end pointers */ + /* don't work, so we discard it and try again. */ + munmap(result, (size_t)(-GC_page_size) - (size_t)result); + /* Leave last page mapped, so we can't repeat. */ + return GC_unix_get_mem(bytes); + } +# else + GC_ASSERT(last_addr != 0); +# endif + return((ptr_t)result); +} + +#else /* Not RS6000, not USE_MMAP */ +ptr_t GC_unix_get_mem(bytes) +word bytes; +{ + ptr_t result; +# ifdef IRIX5 + /* Bare sbrk isn't thread safe. Play by malloc rules. */ + /* The equivalent may be needed on other systems as well. */ + __LOCK_MALLOC(); +# endif + { + ptr_t cur_brk = (ptr_t)sbrk(0); + SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1); + + if ((SBRK_ARG_T)bytes < 0) return(0); /* too big */ + if (lsbs != 0) { + if((ptr_t)sbrk(GC_page_size - lsbs) == (ptr_t)(-1)) return(0); + } + result = (ptr_t)sbrk((SBRK_ARG_T)bytes); + if (result == (ptr_t)(-1)) result = 0; + } +# ifdef IRIX5 + __UNLOCK_MALLOC(); +# endif + return(result); +} + +#endif /* Not USE_MMAP */ +#endif /* Not RS6000 */ + +# endif /* UN*X */ + +# ifdef OS2 + +void * os2_alloc(size_t bytes) +{ + void * result; + + if (DosAllocMem(&result, bytes, PAG_EXECUTE | PAG_READ | + PAG_WRITE | PAG_COMMIT) + != NO_ERROR) { + return(0); + } + if (result == 0) return(os2_alloc(bytes)); + return(result); +} + +# endif /* OS2 */ + + +# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) +SYSTEM_INFO GC_sysinfo; +# endif + +# if defined(MSWIN32) || defined(CYGWIN32) + +word GC_n_heap_bases = 0; + +# ifdef USE_GLOBAL_ALLOC +# define GLOBAL_ALLOC_TEST 1 +# else +# define GLOBAL_ALLOC_TEST GC_no_win32_dlls +# endif + +ptr_t GC_win32_get_mem(bytes) +word bytes; +{ + ptr_t result; + +# ifdef CYGWIN32 + result = GC_unix_get_mem (bytes); +# else + if (GLOBAL_ALLOC_TEST) { + /* VirtualAlloc doesn't like PAGE_EXECUTE_READWRITE. */ + /* There are also unconfirmed rumors of other */ + /* problems, so we dodge the issue. */ + result = (ptr_t) GlobalAlloc(0, bytes + HBLKSIZE); + result = (ptr_t)(((word)result + HBLKSIZE) & ~(HBLKSIZE-1)); + } else { + /* VirtualProtect only works on regions returned by a */ + /* single VirtualAlloc call. Thus we allocate one */ + /* extra page, which will prevent merging of blocks */ + /* in separate regions, and eliminate any temptation */ + /* to call VirtualProtect on a range spanning regions. */ + /* This wastes a small amount of memory, and risks */ + /* increased fragmentation. But better alternatives */ + /* would require effort. */ + result = (ptr_t) VirtualAlloc(NULL, bytes + 1, + MEM_COMMIT | MEM_RESERVE, + PAGE_EXECUTE_READWRITE); + } +#endif + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + /* If I read the documentation correctly, this can */ + /* only happen if HBLKSIZE > 64k or not a power of 2. */ + if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections"); + GC_heap_bases[GC_n_heap_bases++] = result; + return(result); +} + +void GC_win32_free_heap () +{ + if (GC_no_win32_dlls) { + while (GC_n_heap_bases > 0) { +# ifdef CYGWIN32 + free (GC_heap_bases[--GC_n_heap_bases]); +# else + GlobalFree (GC_heap_bases[--GC_n_heap_bases]); +# endif + GC_heap_bases[GC_n_heap_bases] = 0; + } + } +} +# endif + +#ifdef AMIGA +# define GC_AMIGA_AM +# include "AmigaOS.c" +# undef GC_AMIGA_AM +#endif + + +# ifdef MSWINCE +word GC_n_heap_bases = 0; + +ptr_t GC_wince_get_mem(bytes) +word bytes; +{ + ptr_t result; + word i; + + /* Round up allocation size to multiple of page size */ + bytes = (bytes + GC_page_size-1) & ~(GC_page_size-1); + + /* Try to find reserved, uncommitted pages */ + for (i = 0; i < GC_n_heap_bases; i++) { + if (((word)(-(signed_word)GC_heap_lengths[i]) + & (GC_sysinfo.dwAllocationGranularity-1)) + >= bytes) { + result = GC_heap_bases[i] + GC_heap_lengths[i]; + break; + } + } + + if (i == GC_n_heap_bases) { + /* Reserve more pages */ + word res_bytes = (bytes + GC_sysinfo.dwAllocationGranularity-1) + & ~(GC_sysinfo.dwAllocationGranularity-1); + /* If we ever support MPROTECT_VDB here, we will probably need to */ + /* ensure that res_bytes is strictly > bytes, so that VirtualProtect */ + /* never spans regions. It seems to be OK for a VirtualFree argument */ + /* to span regions, so we should be OK for now. */ + result = (ptr_t) VirtualAlloc(NULL, res_bytes, + MEM_RESERVE | MEM_TOP_DOWN, + PAGE_EXECUTE_READWRITE); + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + /* If I read the documentation correctly, this can */ + /* only happen if HBLKSIZE > 64k or not a power of 2. */ + if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections"); + GC_heap_bases[GC_n_heap_bases] = result; + GC_heap_lengths[GC_n_heap_bases] = 0; + GC_n_heap_bases++; + } + + /* Commit pages */ + result = (ptr_t) VirtualAlloc(result, bytes, + MEM_COMMIT, + PAGE_EXECUTE_READWRITE); + if (result != NULL) { + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + GC_heap_lengths[i] += bytes; + } + + return(result); +} +# endif + +#ifdef USE_MUNMAP + +/* For now, this only works on Win32/WinCE and some Unix-like */ +/* systems. If you have something else, don't define */ +/* USE_MUNMAP. */ +/* We assume ANSI C to support this feature. */ + +#if !defined(MSWIN32) && !defined(MSWINCE) + +#include <unistd.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> + +#endif + +/* Compute a page aligned starting address for the unmap */ +/* operation on a block of size bytes starting at start. */ +/* Return 0 if the block is too small to make this feasible. */ +ptr_t GC_unmap_start(ptr_t start, word bytes) +{ + ptr_t result = start; + /* Round start to next page boundary. */ + result += GC_page_size - 1; + result = (ptr_t)((word)result & ~(GC_page_size - 1)); + if (result + GC_page_size > start + bytes) return 0; + return result; +} + +/* Compute end address for an unmap operation on the indicated */ +/* block. */ +ptr_t GC_unmap_end(ptr_t start, word bytes) +{ + ptr_t end_addr = start + bytes; + end_addr = (ptr_t)((word)end_addr & ~(GC_page_size - 1)); + return end_addr; +} + +/* Under Win32/WinCE we commit (map) and decommit (unmap) */ +/* memory using VirtualAlloc and VirtualFree. These functions */ +/* work on individual allocations of virtual memory, made */ +/* previously using VirtualAlloc with the MEM_RESERVE flag. */ +/* The ranges we need to (de)commit may span several of these */ +/* allocations; therefore we use VirtualQuery to check */ +/* allocation lengths, and split up the range as necessary. */ + +/* We assume that GC_remap is called on exactly the same range */ +/* as a previous call to GC_unmap. It is safe to consistently */ +/* round the endpoints in both places. */ +void GC_unmap(ptr_t start, word bytes) +{ + ptr_t start_addr = GC_unmap_start(start, bytes); + ptr_t end_addr = GC_unmap_end(start, bytes); + word len = end_addr - start_addr; + if (0 == start_addr) return; +# if defined(MSWIN32) || defined(MSWINCE) + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word free_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT)) + ABORT("VirtualFree failed"); + GC_unmapped_bytes += free_len; + start_addr += free_len; + len -= free_len; + } +# else + /* We immediately remap it to prevent an intervening mmap from */ + /* accidentally grabbing the same address space. */ + { + void * result; + result = mmap(start_addr, len, PROT_NONE, + MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON, + zero_fd, 0/* offset */); + if (result != (void *)start_addr) ABORT("mmap(...PROT_NONE...) failed"); + } + GC_unmapped_bytes += len; +# endif +} + + +void GC_remap(ptr_t start, word bytes) +{ + ptr_t start_addr = GC_unmap_start(start, bytes); + ptr_t end_addr = GC_unmap_end(start, bytes); + word len = end_addr - start_addr; + +# if defined(MSWIN32) || defined(MSWINCE) + ptr_t result; + + if (0 == start_addr) return; + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word alloc_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + alloc_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + result = VirtualAlloc(start_addr, alloc_len, + MEM_COMMIT, + PAGE_EXECUTE_READWRITE); + if (result != start_addr) { + ABORT("VirtualAlloc remapping failed"); + } + GC_unmapped_bytes -= alloc_len; + start_addr += alloc_len; + len -= alloc_len; + } +# else + /* It was already remapped with PROT_NONE. */ + int result; + + if (0 == start_addr) return; + result = mprotect(start_addr, len, + PROT_READ | PROT_WRITE | OPT_PROT_EXEC); + if (result != 0) { + GC_err_printf3( + "Mprotect failed at 0x%lx (length %ld) with errno %ld\n", + start_addr, len, errno); + ABORT("Mprotect remapping failed"); + } + GC_unmapped_bytes -= len; +# endif +} + +/* Two adjacent blocks have already been unmapped and are about to */ +/* be merged. Unmap the whole block. This typically requires */ +/* that we unmap a small section in the middle that was not previously */ +/* unmapped due to alignment constraints. */ +void GC_unmap_gap(ptr_t start1, word bytes1, ptr_t start2, word bytes2) +{ + ptr_t start1_addr = GC_unmap_start(start1, bytes1); + ptr_t end1_addr = GC_unmap_end(start1, bytes1); + ptr_t start2_addr = GC_unmap_start(start2, bytes2); + ptr_t end2_addr = GC_unmap_end(start2, bytes2); + ptr_t start_addr = end1_addr; + ptr_t end_addr = start2_addr; + word len; + GC_ASSERT(start1 + bytes1 == start2); + if (0 == start1_addr) start_addr = GC_unmap_start(start1, bytes1 + bytes2); + if (0 == start2_addr) end_addr = GC_unmap_end(start1, bytes1 + bytes2); + if (0 == start_addr) return; + len = end_addr - start_addr; +# if defined(MSWIN32) || defined(MSWINCE) + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word free_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT)) + ABORT("VirtualFree failed"); + GC_unmapped_bytes += free_len; + start_addr += free_len; + len -= free_len; + } +# else + if (len != 0 && munmap(start_addr, len) != 0) ABORT("munmap failed"); + GC_unmapped_bytes += len; +# endif +} + +#endif /* USE_MUNMAP */ + +/* Routine for pushing any additional roots. In THREADS */ +/* environment, this is also responsible for marking from */ +/* thread stacks. */ +#ifndef THREADS +void (*GC_push_other_roots)() = 0; +#else /* THREADS */ + +# ifdef PCR +PCR_ERes GC_push_thread_stack(PCR_Th_T *t, PCR_Any dummy) +{ + struct PCR_ThCtl_TInfoRep info; + PCR_ERes result; + + info.ti_stkLow = info.ti_stkHi = 0; + result = PCR_ThCtl_GetInfo(t, &info); + GC_push_all_stack((ptr_t)(info.ti_stkLow), (ptr_t)(info.ti_stkHi)); + return(result); +} + +/* Push the contents of an old object. We treat this as stack */ +/* data only becasue that makes it robust against mark stack */ +/* overflow. */ +PCR_ERes GC_push_old_obj(void *p, size_t size, PCR_Any data) +{ + GC_push_all_stack((ptr_t)p, (ptr_t)p + size); + return(PCR_ERes_okay); +} + + +void GC_default_push_other_roots GC_PROTO((void)) +{ + /* Traverse data allocated by previous memory managers. */ + { + extern struct PCR_MM_ProcsRep * GC_old_allocator; + + if ((*(GC_old_allocator->mmp_enumerate))(PCR_Bool_false, + GC_push_old_obj, 0) + != PCR_ERes_okay) { + ABORT("Old object enumeration failed"); + } + } + /* Traverse all thread stacks. */ + if (PCR_ERes_IsErr( + PCR_ThCtl_ApplyToAllOtherThreads(GC_push_thread_stack,0)) + || PCR_ERes_IsErr(GC_push_thread_stack(PCR_Th_CurrThread(), 0))) { + ABORT("Thread stack marking failed\n"); + } +} + +# endif /* PCR */ + +# ifdef SRC_M3 + +# ifdef ALL_INTERIOR_POINTERS + --> misconfigured +# endif + +void GC_push_thread_structures GC_PROTO((void)) +{ + /* Not our responsibibility. */ +} + +extern void ThreadF__ProcessStacks(); + +void GC_push_thread_stack(start, stop) +word start, stop; +{ + GC_push_all_stack((ptr_t)start, (ptr_t)stop + sizeof(word)); +} + +/* Push routine with M3 specific calling convention. */ +GC_m3_push_root(dummy1, p, dummy2, dummy3) +word *p; +ptr_t dummy1, dummy2; +int dummy3; +{ + word q = *p; + + GC_PUSH_ONE_STACK(q, p); +} + +/* M3 set equivalent to RTHeap.TracedRefTypes */ +typedef struct { int elts[1]; } RefTypeSet; +RefTypeSet GC_TracedRefTypes = {{0x1}}; + +void GC_default_push_other_roots GC_PROTO((void)) +{ + /* Use the M3 provided routine for finding static roots. */ + /* This is a bit dubious, since it presumes no C roots. */ + /* We handle the collector roots explicitly in GC_push_roots */ + RTMain__GlobalMapProc(GC_m3_push_root, 0, GC_TracedRefTypes); + if (GC_words_allocd > 0) { + ThreadF__ProcessStacks(GC_push_thread_stack); + } + /* Otherwise this isn't absolutely necessary, and we have */ + /* startup ordering problems. */ +} + +# endif /* SRC_M3 */ + +# if defined(GC_SOLARIS_THREADS) || defined(GC_PTHREADS) || \ + defined(GC_WIN32_THREADS) + +extern void GC_push_all_stacks(); + +void GC_default_push_other_roots GC_PROTO((void)) +{ + GC_push_all_stacks(); +} + +# endif /* GC_SOLARIS_THREADS || GC_PTHREADS */ + +void (*GC_push_other_roots) GC_PROTO((void)) = GC_default_push_other_roots; + +#endif /* THREADS */ + +/* + * Routines for accessing dirty bits on virtual pages. + * We plan to eventually implement four strategies for doing so: + * DEFAULT_VDB: A simple dummy implementation that treats every page + * as possibly dirty. This makes incremental collection + * useless, but the implementation is still correct. + * PCR_VDB: Use PPCRs virtual dirty bit facility. + * PROC_VDB: Use the /proc facility for reading dirty bits. Only + * works under some SVR4 variants. Even then, it may be + * too slow to be entirely satisfactory. Requires reading + * dirty bits for entire address space. Implementations tend + * to assume that the client is a (slow) debugger. + * MPROTECT_VDB:Protect pages and then catch the faults to keep track of + * dirtied pages. The implementation (and implementability) + * is highly system dependent. This usually fails when system + * calls write to a protected page. We prevent the read system + * call from doing so. It is the clients responsibility to + * make sure that other system calls are similarly protected + * or write only to the stack. + */ +GC_bool GC_dirty_maintained = FALSE; + +# ifdef DEFAULT_VDB + +/* All of the following assume the allocation lock is held, and */ +/* signals are disabled. */ + +/* The client asserts that unallocated pages in the heap are never */ +/* written. */ + +/* Initialize virtual dirty bit implementation. */ +void GC_dirty_init() +{ +# ifdef PRINTSTATS + GC_printf0("Initializing DEFAULT_VDB...\n"); +# endif + GC_dirty_maintained = TRUE; +} + +/* Retrieve system dirty bits for heap to a local buffer. */ +/* Restore the systems notion of which pages are dirty. */ +void GC_read_dirty() +{} + +/* Is the HBLKSIZE sized page at h marked dirty in the local buffer? */ +/* If the actual page size is different, this returns TRUE if any */ +/* of the pages overlapping h are dirty. This routine may err on the */ +/* side of labelling pages as dirty (and this implementation does). */ +/*ARGSUSED*/ +GC_bool GC_page_was_dirty(h) +struct hblk *h; +{ + return(TRUE); +} + +/* + * The following two routines are typically less crucial. They matter + * most with large dynamic libraries, or if we can't accurately identify + * stacks, e.g. under Solaris 2.X. Otherwise the following default + * versions are adequate. + */ + +/* Could any valid GC heap pointer ever have been written to this page? */ +/*ARGSUSED*/ +GC_bool GC_page_was_ever_dirty(h) +struct hblk *h; +{ + return(TRUE); +} + +/* Reset the n pages starting at h to "was never dirty" status. */ +void GC_is_fresh(h, n) +struct hblk *h; +word n; +{ +} + +/* A call that: */ +/* I) hints that [h, h+nblocks) is about to be written. */ +/* II) guarantees that protection is removed. */ +/* (I) may speed up some dirty bit implementations. */ +/* (II) may be essential if we need to ensure that */ +/* pointer-free system call buffers in the heap are */ +/* not protected. */ +/*ARGSUSED*/ +void GC_remove_protection(h, nblocks, is_ptrfree) +struct hblk *h; +word nblocks; +GC_bool is_ptrfree; +{ +} + +# endif /* DEFAULT_VDB */ + + +# ifdef MPROTECT_VDB + +/* + * See DEFAULT_VDB for interface descriptions. + */ + +/* + * This implementation maintains dirty bits itself by catching write + * faults and keeping track of them. We assume nobody else catches + * SIGBUS or SIGSEGV. We assume no write faults occur in system calls. + * This means that clients must ensure that system calls don't write + * to the write-protected heap. Probably the best way to do this is to + * ensure that system calls write at most to POINTERFREE objects in the + * heap, and do even that only if we are on a platform on which those + * are not protected. Another alternative is to wrap system calls + * (see example for read below), but the current implementation holds + * a lock across blocking calls, making it problematic for multithreaded + * applications. + * We assume the page size is a multiple of HBLKSIZE. + * We prefer them to be the same. We avoid protecting POINTERFREE + * objects only if they are the same. + */ + +# if !defined(MSWIN32) && !defined(MSWINCE) && !defined(DARWIN) + +# include <sys/mman.h> +# include <signal.h> +# include <sys/syscall.h> + +# define PROTECT(addr, len) \ + if (mprotect((caddr_t)(addr), (size_t)(len), \ + PROT_READ | OPT_PROT_EXEC) < 0) { \ + ABORT("mprotect failed"); \ + } +# define UNPROTECT(addr, len) \ + if (mprotect((caddr_t)(addr), (size_t)(len), \ + PROT_WRITE | PROT_READ | OPT_PROT_EXEC ) < 0) { \ + ABORT("un-mprotect failed"); \ + } + +# else + +# ifdef DARWIN + /* Using vm_protect (mach syscall) over mprotect (BSD syscall) seems to + decrease the likelihood of some of the problems described below. */ + #include <mach/vm_map.h> + static mach_port_t GC_task_self; + #define PROTECT(addr,len) \ + if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \ + FALSE,VM_PROT_READ) != KERN_SUCCESS) { \ + ABORT("vm_portect failed"); \ + } + #define UNPROTECT(addr,len) \ + if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \ + FALSE,VM_PROT_READ|VM_PROT_WRITE) != KERN_SUCCESS) { \ + ABORT("vm_portect failed"); \ + } +# else + +# ifndef MSWINCE +# include <signal.h> +# endif + + static DWORD protect_junk; +# define PROTECT(addr, len) \ + if (!VirtualProtect((addr), (len), PAGE_EXECUTE_READ, \ + &protect_junk)) { \ + DWORD last_error = GetLastError(); \ + GC_printf1("Last error code: %lx\n", last_error); \ + ABORT("VirtualProtect failed"); \ + } +# define UNPROTECT(addr, len) \ + if (!VirtualProtect((addr), (len), PAGE_EXECUTE_READWRITE, \ + &protect_junk)) { \ + ABORT("un-VirtualProtect failed"); \ + } +# endif /* !DARWIN */ +# endif /* MSWIN32 || MSWINCE || DARWIN */ + +#if defined(SUNOS4) || (defined(FREEBSD) && !defined(SUNOS5SIGS)) + typedef void (* SIG_PF)(); +#endif /* SUNOS4 || (FREEBSD && !SUNOS5SIGS) */ + +#if defined(SUNOS5SIGS) || defined(OSF1) || defined(LINUX) \ + || defined(HURD) +# ifdef __STDC__ + typedef void (* SIG_PF)(int); +# else + typedef void (* SIG_PF)(); +# endif +#endif /* SUNOS5SIGS || OSF1 || LINUX || HURD */ + +#if defined(MSWIN32) + typedef LPTOP_LEVEL_EXCEPTION_FILTER SIG_PF; +# undef SIG_DFL +# define SIG_DFL (LPTOP_LEVEL_EXCEPTION_FILTER) (-1) +#endif +#if defined(MSWINCE) + typedef LONG (WINAPI *SIG_PF)(struct _EXCEPTION_POINTERS *); +# undef SIG_DFL +# define SIG_DFL (SIG_PF) (-1) +#endif + +#if defined(IRIX5) || defined(OSF1) || defined(HURD) + typedef void (* REAL_SIG_PF)(int, int, struct sigcontext *); +#endif /* IRIX5 || OSF1 || HURD */ + +#if defined(SUNOS5SIGS) +# if defined(HPUX) || defined(FREEBSD) +# define SIGINFO_T siginfo_t +# else +# define SIGINFO_T struct siginfo +# endif +# ifdef __STDC__ + typedef void (* REAL_SIG_PF)(int, SIGINFO_T *, void *); +# else + typedef void (* REAL_SIG_PF)(); +# endif +#endif /* SUNOS5SIGS */ + +#if defined(LINUX) +# if __GLIBC__ > 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ >= 2 + typedef struct sigcontext s_c; +# else /* glibc < 2.2 */ +# include <linux/version.h> +# if (LINUX_VERSION_CODE >= 0x20100) && !defined(M68K) || defined(ALPHA) || defined(ARM32) + typedef struct sigcontext s_c; +# else + typedef struct sigcontext_struct s_c; +# endif +# endif /* glibc < 2.2 */ +# if defined(ALPHA) || defined(M68K) + typedef void (* REAL_SIG_PF)(int, int, s_c *); +# else +# if defined(IA64) || defined(HP_PA) || defined(X86_64) + typedef void (* REAL_SIG_PF)(int, siginfo_t *, s_c *); + /* FIXME: */ + /* According to SUSV3, the last argument should have type */ + /* void * or ucontext_t * */ +# else + typedef void (* REAL_SIG_PF)(int, s_c); +# endif +# endif +# ifdef ALPHA + /* Retrieve fault address from sigcontext structure by decoding */ + /* instruction. */ + char * get_fault_addr(s_c *sc) { + unsigned instr; + word faultaddr; + + instr = *((unsigned *)(sc->sc_pc)); + faultaddr = sc->sc_regs[(instr >> 16) & 0x1f]; + faultaddr += (word) (((int)instr << 16) >> 16); + return (char *)faultaddr; + } +# endif /* !ALPHA */ +# endif /* LINUX */ + +#ifndef DARWIN +SIG_PF GC_old_bus_handler; +SIG_PF GC_old_segv_handler; /* Also old MSWIN32 ACCESS_VIOLATION filter */ +#endif /* !DARWIN */ + +#if defined(THREADS) +/* We need to lock around the bitmap update in the write fault handler */ +/* in order to avoid the risk of losing a bit. We do this with a */ +/* test-and-set spin lock if we know how to do that. Otherwise we */ +/* check whether we are already in the handler and use the dumb but */ +/* safe fallback algorithm of setting all bits in the word. */ +/* Contention should be very rare, so we do the minimum to handle it */ +/* correctly. */ +#ifdef GC_TEST_AND_SET_DEFINED + static VOLATILE unsigned int fault_handler_lock = 0; + void async_set_pht_entry_from_index(VOLATILE page_hash_table db, int index) { + while (GC_test_and_set(&fault_handler_lock)) {} + /* Could also revert to set_pht_entry_from_index_safe if initial */ + /* GC_test_and_set fails. */ + set_pht_entry_from_index(db, index); + GC_clear(&fault_handler_lock); + } +#else /* !GC_TEST_AND_SET_DEFINED */ + /* THIS IS INCORRECT! The dirty bit vector may be temporarily wrong, */ + /* just before we notice the conflict and correct it. We may end up */ + /* looking at it while it's wrong. But this requires contention */ + /* exactly when a GC is triggered, which seems far less likely to */ + /* fail than the old code, which had no reported failures. Thus we */ + /* leave it this way while we think of something better, or support */ + /* GC_test_and_set on the remaining platforms. */ + static VOLATILE word currently_updating = 0; + void async_set_pht_entry_from_index(VOLATILE page_hash_table db, int index) { + unsigned int update_dummy; + currently_updating = (word)(&update_dummy); + set_pht_entry_from_index(db, index); + /* If we get contention in the 10 or so instruction window here, */ + /* and we get stopped by a GC between the two updates, we lose! */ + if (currently_updating != (word)(&update_dummy)) { + set_pht_entry_from_index_safe(db, index); + /* We claim that if two threads concurrently try to update the */ + /* dirty bit vector, the first one to execute UPDATE_START */ + /* will see it changed when UPDATE_END is executed. (Note that */ + /* &update_dummy must differ in two distinct threads.) It */ + /* will then execute set_pht_entry_from_index_safe, thus */ + /* returning us to a safe state, though not soon enough. */ + } + } +#endif /* !GC_TEST_AND_SET_DEFINED */ +#else /* !THREADS */ +# define async_set_pht_entry_from_index(db, index) \ + set_pht_entry_from_index(db, index) +#endif /* !THREADS */ + +/*ARGSUSED*/ +#if !defined(DARWIN) +# if defined (SUNOS4) || (defined(FREEBSD) && !defined(SUNOS5SIGS)) + void GC_write_fault_handler(sig, code, scp, addr) + int sig, code; + struct sigcontext *scp; + char * addr; +# ifdef SUNOS4 +# define SIG_OK (sig == SIGSEGV || sig == SIGBUS) +# define CODE_OK (FC_CODE(code) == FC_PROT \ + || (FC_CODE(code) == FC_OBJERR \ + && FC_ERRNO(code) == FC_PROT)) +# endif +# ifdef FREEBSD +# define SIG_OK (sig == SIGBUS) +# define CODE_OK TRUE +# endif +# endif /* SUNOS4 || (FREEBSD && !SUNOS5SIGS) */ + +# if defined(IRIX5) || defined(OSF1) || defined(HURD) +# include <errno.h> + void GC_write_fault_handler(int sig, int code, struct sigcontext *scp) +# ifdef OSF1 +# define SIG_OK (sig == SIGSEGV) +# define CODE_OK (code == 2 /* experimentally determined */) +# endif +# ifdef IRIX5 +# define SIG_OK (sig == SIGSEGV) +# define CODE_OK (code == EACCES) +# endif +# ifdef HURD +# define SIG_OK (sig == SIGBUS || sig == SIGSEGV) +# define CODE_OK TRUE +# endif +# endif /* IRIX5 || OSF1 || HURD */ + +# if defined(LINUX) +# if defined(ALPHA) || defined(M68K) + void GC_write_fault_handler(int sig, int code, s_c * sc) +# else +# if defined(IA64) || defined(HP_PA) || defined(X86_64) + void GC_write_fault_handler(int sig, siginfo_t * si, s_c * scp) +# else +# if defined(ARM32) + void GC_write_fault_handler(int sig, int a2, int a3, int a4, s_c sc) +# else + void GC_write_fault_handler(int sig, s_c sc) +# endif +# endif +# endif +# define SIG_OK (sig == SIGSEGV) +# define CODE_OK TRUE + /* Empirically c.trapno == 14, on IA32, but is that useful? */ + /* Should probably consider alignment issues on other */ + /* architectures. */ +# endif /* LINUX */ + +# if defined(SUNOS5SIGS) +# ifdef __STDC__ + void GC_write_fault_handler(int sig, SIGINFO_T *scp, void * context) +# else + void GC_write_fault_handler(sig, scp, context) + int sig; + SIGINFO_T *scp; + void * context; +# endif +# ifdef HPUX +# define SIG_OK (sig == SIGSEGV || sig == SIGBUS) +# define CODE_OK (scp -> si_code == SEGV_ACCERR) \ + || (scp -> si_code == BUS_ADRERR) \ + || (scp -> si_code == BUS_UNKNOWN) \ + || (scp -> si_code == SEGV_UNKNOWN) \ + || (scp -> si_code == BUS_OBJERR) +# else +# ifdef FREEBSD +# define SIG_OK (sig == SIGBUS) +# define CODE_OK (scp -> si_code == BUS_PAGE_FAULT) +# else +# define SIG_OK (sig == SIGSEGV) +# define CODE_OK (scp -> si_code == SEGV_ACCERR) +# endif +# endif +# endif /* SUNOS5SIGS */ + +# if defined(MSWIN32) || defined(MSWINCE) + LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info) +# define SIG_OK (exc_info -> ExceptionRecord -> ExceptionCode == \ + STATUS_ACCESS_VIOLATION) +# define CODE_OK (exc_info -> ExceptionRecord -> ExceptionInformation[0] == 1) + /* Write fault */ +# endif /* MSWIN32 || MSWINCE */ +{ + register unsigned i; +# if defined(HURD) + char *addr = (char *) code; +# endif +# ifdef IRIX5 + char * addr = (char *) (size_t) (scp -> sc_badvaddr); +# endif +# if defined(OSF1) && defined(ALPHA) + char * addr = (char *) (scp -> sc_traparg_a0); +# endif +# ifdef SUNOS5SIGS + char * addr = (char *) (scp -> si_addr); +# endif +# ifdef LINUX +# if defined(I386) + char * addr = (char *) (sc.cr2); +# else +# if defined(M68K) + char * addr = NULL; + + struct sigcontext *scp = (struct sigcontext *)(sc); + + int format = (scp->sc_formatvec >> 12) & 0xf; + unsigned long *framedata = (unsigned long *)(scp + 1); + unsigned long ea; + + if (format == 0xa || format == 0xb) { + /* 68020/030 */ + ea = framedata[2]; + } else if (format == 7) { + /* 68040 */ + ea = framedata[3]; + if (framedata[1] & 0x08000000) { + /* correct addr on misaligned access */ + ea = (ea+4095)&(~4095); + } + } else if (format == 4) { + /* 68060 */ + ea = framedata[0]; + if (framedata[1] & 0x08000000) { + /* correct addr on misaligned access */ + ea = (ea+4095)&(~4095); + } + } + addr = (char *)ea; +# else +# ifdef ALPHA + char * addr = get_fault_addr(sc); +# else +# if defined(IA64) || defined(HP_PA) || defined(X86_64) + char * addr = si -> si_addr; + /* I believe this is claimed to work on all platforms for */ + /* Linux 2.3.47 and later. Hopefully we don't have to */ + /* worry about earlier kernels on IA64. */ +# else +# if defined(POWERPC) + char * addr = (char *) (sc.regs->dar); +# else +# if defined(ARM32) + char * addr = (char *)sc.fault_address; +# else +# if defined(CRIS) + char * addr = (char *)sc.regs.csraddr; +# else + --> architecture not supported +# endif +# endif +# endif +# endif +# endif +# endif +# endif +# endif +# if defined(MSWIN32) || defined(MSWINCE) + char * addr = (char *) (exc_info -> ExceptionRecord + -> ExceptionInformation[1]); +# define sig SIGSEGV +# endif + + if (SIG_OK && CODE_OK) { + register struct hblk * h = + (struct hblk *)((word)addr & ~(GC_page_size-1)); + GC_bool in_allocd_block; + +# ifdef SUNOS5SIGS + /* Address is only within the correct physical page. */ + in_allocd_block = FALSE; + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + if (HDR(h+i) != 0) { + in_allocd_block = TRUE; + } + } +# else + in_allocd_block = (HDR(addr) != 0); +# endif + if (!in_allocd_block) { + /* FIXME - We should make sure that we invoke the */ + /* old handler with the appropriate calling */ + /* sequence, which often depends on SA_SIGINFO. */ + + /* Heap blocks now begin and end on page boundaries */ + SIG_PF old_handler; + + if (sig == SIGSEGV) { + old_handler = GC_old_segv_handler; + } else { + old_handler = GC_old_bus_handler; + } + if (old_handler == SIG_DFL) { +# if !defined(MSWIN32) && !defined(MSWINCE) + GC_err_printf1("Segfault at 0x%lx\n", addr); + ABORT("Unexpected bus error or segmentation fault"); +# else + return(EXCEPTION_CONTINUE_SEARCH); +# endif + } else { +# if defined (SUNOS4) \ + || (defined(FREEBSD) && !defined(SUNOS5SIGS)) + (*old_handler) (sig, code, scp, addr); + return; +# endif +# if defined (SUNOS5SIGS) + /* + * FIXME: For FreeBSD, this code should check if the + * old signal handler used the traditional BSD style and + * if so call it using that style. + */ + (*(REAL_SIG_PF)old_handler) (sig, scp, context); + return; +# endif +# if defined (LINUX) +# if defined(ALPHA) || defined(M68K) + (*(REAL_SIG_PF)old_handler) (sig, code, sc); +# else +# if defined(IA64) || defined(HP_PA) || defined(X86_64) + (*(REAL_SIG_PF)old_handler) (sig, si, scp); +# else + (*(REAL_SIG_PF)old_handler) (sig, sc); +# endif +# endif + return; +# endif +# if defined (IRIX5) || defined(OSF1) || defined(HURD) + (*(REAL_SIG_PF)old_handler) (sig, code, scp); + return; +# endif +# ifdef MSWIN32 + return((*old_handler)(exc_info)); +# endif + } + } + UNPROTECT(h, GC_page_size); + /* We need to make sure that no collection occurs between */ + /* the UNPROTECT and the setting of the dirty bit. Otherwise */ + /* a write by a third thread might go unnoticed. Reversing */ + /* the order is just as bad, since we would end up unprotecting */ + /* a page in a GC cycle during which it's not marked. */ + /* Currently we do this by disabling the thread stopping */ + /* signals while this handler is running. An alternative might */ + /* be to record the fact that we're about to unprotect, or */ + /* have just unprotected a page in the GC's thread structure, */ + /* and then to have the thread stopping code set the dirty */ + /* flag, if necessary. */ + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + register int index = PHT_HASH(h+i); + + async_set_pht_entry_from_index(GC_dirty_pages, index); + } +# if defined(OSF1) + /* These reset the signal handler each time by default. */ + signal(SIGSEGV, (SIG_PF) GC_write_fault_handler); +# endif + /* The write may not take place before dirty bits are read. */ + /* But then we'll fault again ... */ +# if defined(MSWIN32) || defined(MSWINCE) + return(EXCEPTION_CONTINUE_EXECUTION); +# else + return; +# endif + } +#if defined(MSWIN32) || defined(MSWINCE) + return EXCEPTION_CONTINUE_SEARCH; +#else + GC_err_printf1("Segfault at 0x%lx\n", addr); + ABORT("Unexpected bus error or segmentation fault"); +#endif +} +#endif /* !DARWIN */ + +/* + * We hold the allocation lock. We expect block h to be written + * shortly. Ensure that all pages containing any part of the n hblks + * starting at h are no longer protected. If is_ptrfree is false, + * also ensure that they will subsequently appear to be dirty. + */ +void GC_remove_protection(h, nblocks, is_ptrfree) +struct hblk *h; +word nblocks; +GC_bool is_ptrfree; +{ + struct hblk * h_trunc; /* Truncated to page boundary */ + struct hblk * h_end; /* Page boundary following block end */ + struct hblk * current; + GC_bool found_clean; + + if (!GC_dirty_maintained) return; + h_trunc = (struct hblk *)((word)h & ~(GC_page_size-1)); + h_end = (struct hblk *)(((word)(h + nblocks) + GC_page_size-1) + & ~(GC_page_size-1)); + found_clean = FALSE; + for (current = h_trunc; current < h_end; ++current) { + int index = PHT_HASH(current); + + if (!is_ptrfree || current < h || current >= h + nblocks) { + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + } + UNPROTECT(h_trunc, (ptr_t)h_end - (ptr_t)h_trunc); +} + +#if !defined(DARWIN) +void GC_dirty_init() +{ +# if defined(SUNOS5SIGS) || defined(IRIX5) || defined(LINUX) || \ + defined(OSF1) || defined(HURD) + struct sigaction act, oldact; + /* We should probably specify SA_SIGINFO for Linux, and handle */ + /* the different architectures more uniformly. */ +# if defined(IRIX5) || defined(LINUX) && !defined(X86_64) \ + || defined(OSF1) || defined(HURD) + act.sa_flags = SA_RESTART; + act.sa_handler = (SIG_PF)GC_write_fault_handler; +# else + act.sa_flags = SA_RESTART | SA_SIGINFO; + act.sa_sigaction = GC_write_fault_handler; +# endif + (void)sigemptyset(&act.sa_mask); +# ifdef SIG_SUSPEND + /* Arrange to postpone SIG_SUSPEND while we're in a write fault */ + /* handler. This effectively makes the handler atomic w.r.t. */ + /* stopping the world for GC. */ + (void)sigaddset(&act.sa_mask, SIG_SUSPEND); +# endif /* SIG_SUSPEND */ +# endif +# ifdef PRINTSTATS + GC_printf0("Inititalizing mprotect virtual dirty bit implementation\n"); +# endif + GC_dirty_maintained = TRUE; + if (GC_page_size % HBLKSIZE != 0) { + GC_err_printf0("Page size not multiple of HBLKSIZE\n"); + ABORT("Page size not multiple of HBLKSIZE"); + } +# if defined(SUNOS4) || (defined(FREEBSD) && !defined(SUNOS5SIGS)) + GC_old_bus_handler = signal(SIGBUS, GC_write_fault_handler); + if (GC_old_bus_handler == SIG_IGN) { + GC_err_printf0("Previously ignored bus error!?"); + GC_old_bus_handler = SIG_DFL; + } + if (GC_old_bus_handler != SIG_DFL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other SIGBUS handler\n"); +# endif + } +# endif +# if defined(SUNOS4) + GC_old_segv_handler = signal(SIGSEGV, (SIG_PF)GC_write_fault_handler); + if (GC_old_segv_handler == SIG_IGN) { + GC_err_printf0("Previously ignored segmentation violation!?"); + GC_old_segv_handler = SIG_DFL; + } + if (GC_old_segv_handler != SIG_DFL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other SIGSEGV handler\n"); +# endif + } +# endif +# if (defined(SUNOS5SIGS) && !defined(FREEBSD)) || defined(IRIX5) \ + || defined(LINUX) || defined(OSF1) || defined(HURD) + /* SUNOS5SIGS includes HPUX */ +# if defined(GC_IRIX_THREADS) + sigaction(SIGSEGV, 0, &oldact); + sigaction(SIGSEGV, &act, 0); +# else + { + int res = sigaction(SIGSEGV, &act, &oldact); + if (res != 0) ABORT("Sigaction failed"); + } +# endif +# if defined(_sigargs) || defined(HURD) || !defined(SA_SIGINFO) + /* This is Irix 5.x, not 6.x. Irix 5.x does not have */ + /* sa_sigaction. */ + GC_old_segv_handler = oldact.sa_handler; +# else /* Irix 6.x or SUNOS5SIGS or LINUX */ + if (oldact.sa_flags & SA_SIGINFO) { + GC_old_segv_handler = (SIG_PF)(oldact.sa_sigaction); + } else { + GC_old_segv_handler = oldact.sa_handler; + } +# endif + if (GC_old_segv_handler == SIG_IGN) { + GC_err_printf0("Previously ignored segmentation violation!?"); + GC_old_segv_handler = SIG_DFL; + } + if (GC_old_segv_handler != SIG_DFL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other SIGSEGV handler\n"); +# endif + } +# endif /* (SUNOS5SIGS && !FREEBSD) || IRIX5 || LINUX || OSF1 || HURD */ +# if defined(HPUX) || defined(LINUX) || defined(HURD) \ + || (defined(FREEBSD) && defined(SUNOS5SIGS)) + sigaction(SIGBUS, &act, &oldact); + GC_old_bus_handler = oldact.sa_handler; + if (GC_old_bus_handler == SIG_IGN) { + GC_err_printf0("Previously ignored bus error!?"); + GC_old_bus_handler = SIG_DFL; + } + if (GC_old_bus_handler != SIG_DFL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other SIGBUS handler\n"); +# endif + } +# endif /* HPUX || LINUX || HURD || (FREEBSD && SUNOS5SIGS) */ +# if defined(MSWIN32) + GC_old_segv_handler = SetUnhandledExceptionFilter(GC_write_fault_handler); + if (GC_old_segv_handler != NULL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other UnhandledExceptionFilter\n"); +# endif + } else { + GC_old_segv_handler = SIG_DFL; + } +# endif +} +#endif /* !DARWIN */ + +int GC_incremental_protection_needs() +{ + if (GC_page_size == HBLKSIZE) { + return GC_PROTECTS_POINTER_HEAP; + } else { + return GC_PROTECTS_POINTER_HEAP | GC_PROTECTS_PTRFREE_HEAP; + } +} + +#define HAVE_INCREMENTAL_PROTECTION_NEEDS + +#define IS_PTRFREE(hhdr) ((hhdr)->hb_descr == 0) + +#define PAGE_ALIGNED(x) !((word)(x) & (GC_page_size - 1)) +void GC_protect_heap() +{ + ptr_t start; + word len; + struct hblk * current; + struct hblk * current_start; /* Start of block to be protected. */ + struct hblk * limit; + unsigned i; + GC_bool protect_all = + (0 != (GC_incremental_protection_needs() & GC_PROTECTS_PTRFREE_HEAP)); + for (i = 0; i < GC_n_heap_sects; i++) { + start = GC_heap_sects[i].hs_start; + len = GC_heap_sects[i].hs_bytes; + if (protect_all) { + PROTECT(start, len); + } else { + GC_ASSERT(PAGE_ALIGNED(len)) + GC_ASSERT(PAGE_ALIGNED(start)) + current_start = current = (struct hblk *)start; + limit = (struct hblk *)(start + len); + while (current < limit) { + hdr * hhdr; + word nhblks; + GC_bool is_ptrfree; + + GC_ASSERT(PAGE_ALIGNED(current)); + GET_HDR(current, hhdr); + if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) { + /* This can happen only if we're at the beginning of a */ + /* heap segment, and a block spans heap segments. */ + /* We will handle that block as part of the preceding */ + /* segment. */ + GC_ASSERT(current_start == current); + current_start = ++current; + continue; + } + if (HBLK_IS_FREE(hhdr)) { + GC_ASSERT(PAGE_ALIGNED(hhdr -> hb_sz)); + nhblks = divHBLKSZ(hhdr -> hb_sz); + is_ptrfree = TRUE; /* dirty on alloc */ + } else { + nhblks = OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz); + is_ptrfree = IS_PTRFREE(hhdr); + } + if (is_ptrfree) { + if (current_start < current) { + PROTECT(current_start, (ptr_t)current - (ptr_t)current_start); + } + current_start = (current += nhblks); + } else { + current += nhblks; + } + } + if (current_start < current) { + PROTECT(current_start, (ptr_t)current - (ptr_t)current_start); + } + } + } +} + +/* We assume that either the world is stopped or its OK to lose dirty */ +/* bits while this is happenning (as in GC_enable_incremental). */ +void GC_read_dirty() +{ + BCOPY((word *)GC_dirty_pages, GC_grungy_pages, + (sizeof GC_dirty_pages)); + BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages)); + GC_protect_heap(); +} + +GC_bool GC_page_was_dirty(h) +struct hblk * h; +{ + register word index = PHT_HASH(h); + + return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index)); +} + +/* + * Acquiring the allocation lock here is dangerous, since this + * can be called from within GC_call_with_alloc_lock, and the cord + * package does so. On systems that allow nested lock acquisition, this + * happens to work. + * On other systems, SET_LOCK_HOLDER and friends must be suitably defined. + */ + +static GC_bool syscall_acquired_lock = FALSE; /* Protected by GC lock. */ + +void GC_begin_syscall() +{ + if (!I_HOLD_LOCK()) { + LOCK(); + syscall_acquired_lock = TRUE; + } +} + +void GC_end_syscall() +{ + if (syscall_acquired_lock) { + syscall_acquired_lock = FALSE; + UNLOCK(); + } +} + +void GC_unprotect_range(addr, len) +ptr_t addr; +word len; +{ + struct hblk * start_block; + struct hblk * end_block; + register struct hblk *h; + ptr_t obj_start; + + if (!GC_dirty_maintained) return; + obj_start = GC_base(addr); + if (obj_start == 0) return; + if (GC_base(addr + len - 1) != obj_start) { + ABORT("GC_unprotect_range(range bigger than object)"); + } + start_block = (struct hblk *)((word)addr & ~(GC_page_size - 1)); + end_block = (struct hblk *)((word)(addr + len - 1) & ~(GC_page_size - 1)); + end_block += GC_page_size/HBLKSIZE - 1; + for (h = start_block; h <= end_block; h++) { + register word index = PHT_HASH(h); + + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + UNPROTECT(start_block, + ((ptr_t)end_block - (ptr_t)start_block) + HBLKSIZE); +} + +#if 0 + +/* We no longer wrap read by default, since that was causing too many */ +/* problems. It is preferred that the client instead avoids writing */ +/* to the write-protected heap with a system call. */ +/* This still serves as sample code if you do want to wrap system calls.*/ + +#if !defined(MSWIN32) && !defined(MSWINCE) && !defined(GC_USE_LD_WRAP) +/* Replacement for UNIX system call. */ +/* Other calls that write to the heap should be handled similarly. */ +/* Note that this doesn't work well for blocking reads: It will hold */ +/* the allocation lock for the entire duration of the call. Multithreaded */ +/* clients should really ensure that it won't block, either by setting */ +/* the descriptor nonblocking, or by calling select or poll first, to */ +/* make sure that input is available. */ +/* Another, preferred alternative is to ensure that system calls never */ +/* write to the protected heap (see above). */ +# if defined(__STDC__) && !defined(SUNOS4) +# include <unistd.h> +# include <sys/uio.h> + ssize_t read(int fd, void *buf, size_t nbyte) +# else +# ifndef LINT + int read(fd, buf, nbyte) +# else + int GC_read(fd, buf, nbyte) +# endif + int fd; + char *buf; + int nbyte; +# endif +{ + int result; + + GC_begin_syscall(); + GC_unprotect_range(buf, (word)nbyte); +# if defined(IRIX5) || defined(GC_LINUX_THREADS) + /* Indirect system call may not always be easily available. */ + /* We could call _read, but that would interfere with the */ + /* libpthread interception of read. */ + /* On Linux, we have to be careful with the linuxthreads */ + /* read interception. */ + { + struct iovec iov; + + iov.iov_base = buf; + iov.iov_len = nbyte; + result = readv(fd, &iov, 1); + } +# else +# if defined(HURD) + result = __read(fd, buf, nbyte); +# else + /* The two zero args at the end of this list are because one + IA-64 syscall() implementation actually requires six args + to be passed, even though they aren't always used. */ + result = syscall(SYS_read, fd, buf, nbyte, 0, 0); +# endif /* !HURD */ +# endif + GC_end_syscall(); + return(result); +} +#endif /* !MSWIN32 && !MSWINCE && !GC_LINUX_THREADS */ + +#if defined(GC_USE_LD_WRAP) && !defined(THREADS) + /* We use the GNU ld call wrapping facility. */ + /* This requires that the linker be invoked with "--wrap read". */ + /* This can be done by passing -Wl,"--wrap read" to gcc. */ + /* I'm not sure that this actually wraps whatever version of read */ + /* is called by stdio. That code also mentions __read. */ +# include <unistd.h> + ssize_t __wrap_read(int fd, void *buf, size_t nbyte) + { + int result; + + GC_begin_syscall(); + GC_unprotect_range(buf, (word)nbyte); + result = __real_read(fd, buf, nbyte); + GC_end_syscall(); + return(result); + } + + /* We should probably also do this for __read, or whatever stdio */ + /* actually calls. */ +#endif + +#endif /* 0 */ + +/*ARGSUSED*/ +GC_bool GC_page_was_ever_dirty(h) +struct hblk *h; +{ + return(TRUE); +} + +/* Reset the n pages starting at h to "was never dirty" status. */ +/*ARGSUSED*/ +void GC_is_fresh(h, n) +struct hblk *h; +word n; +{ +} + +# endif /* MPROTECT_VDB */ + +# ifdef PROC_VDB + +/* + * See DEFAULT_VDB for interface descriptions. + */ + +/* + * This implementaion assumes a Solaris 2.X like /proc pseudo-file-system + * from which we can read page modified bits. This facility is far from + * optimal (e.g. we would like to get the info for only some of the + * address space), but it avoids intercepting system calls. + */ + +#include <errno.h> +#include <sys/types.h> +#include <sys/signal.h> +#include <sys/fault.h> +#include <sys/syscall.h> +#include <sys/procfs.h> +#include <sys/stat.h> + +#define INITIAL_BUF_SZ 16384 +word GC_proc_buf_size = INITIAL_BUF_SZ; +char *GC_proc_buf; + +#ifdef GC_SOLARIS_THREADS +/* We don't have exact sp values for threads. So we count on */ +/* occasionally declaring stack pages to be fresh. Thus we */ +/* need a real implementation of GC_is_fresh. We can't clear */ +/* entries in GC_written_pages, since that would declare all */ +/* pages with the given hash address to be fresh. */ +# define MAX_FRESH_PAGES 8*1024 /* Must be power of 2 */ + struct hblk ** GC_fresh_pages; /* A direct mapped cache. */ + /* Collisions are dropped. */ + +# define FRESH_PAGE_SLOT(h) (divHBLKSZ((word)(h)) & (MAX_FRESH_PAGES-1)) +# define ADD_FRESH_PAGE(h) \ + GC_fresh_pages[FRESH_PAGE_SLOT(h)] = (h) +# define PAGE_IS_FRESH(h) \ + (GC_fresh_pages[FRESH_PAGE_SLOT(h)] == (h) && (h) != 0) +#endif + +/* Add all pages in pht2 to pht1 */ +void GC_or_pages(pht1, pht2) +page_hash_table pht1, pht2; +{ + register int i; + + for (i = 0; i < PHT_SIZE; i++) pht1[i] |= pht2[i]; +} + +int GC_proc_fd; + +void GC_dirty_init() +{ + int fd; + char buf[30]; + + GC_dirty_maintained = TRUE; + if (GC_words_allocd != 0 || GC_words_allocd_before_gc != 0) { + register int i; + + for (i = 0; i < PHT_SIZE; i++) GC_written_pages[i] = (word)(-1); +# ifdef PRINTSTATS + GC_printf1("Allocated words:%lu:all pages may have been written\n", + (unsigned long) + (GC_words_allocd + GC_words_allocd_before_gc)); +# endif + } + sprintf(buf, "/proc/%d", getpid()); + fd = open(buf, O_RDONLY); + if (fd < 0) { + ABORT("/proc open failed"); + } + GC_proc_fd = syscall(SYS_ioctl, fd, PIOCOPENPD, 0); + close(fd); + syscall(SYS_fcntl, GC_proc_fd, F_SETFD, FD_CLOEXEC); + if (GC_proc_fd < 0) { + ABORT("/proc ioctl failed"); + } + GC_proc_buf = GC_scratch_alloc(GC_proc_buf_size); +# ifdef GC_SOLARIS_THREADS + GC_fresh_pages = (struct hblk **) + GC_scratch_alloc(MAX_FRESH_PAGES * sizeof (struct hblk *)); + if (GC_fresh_pages == 0) { + GC_err_printf0("No space for fresh pages\n"); + EXIT(); + } + BZERO(GC_fresh_pages, MAX_FRESH_PAGES * sizeof (struct hblk *)); +# endif +} + +/* Ignore write hints. They don't help us here. */ +/*ARGSUSED*/ +void GC_remove_protection(h, nblocks, is_ptrfree) +struct hblk *h; +word nblocks; +GC_bool is_ptrfree; +{ +} + +#ifdef GC_SOLARIS_THREADS +# define READ(fd,buf,nbytes) syscall(SYS_read, fd, buf, nbytes) +#else +# define READ(fd,buf,nbytes) read(fd, buf, nbytes) +#endif + +void GC_read_dirty() +{ + unsigned long ps, np; + int nmaps; + ptr_t vaddr; + struct prasmap * map; + char * bufp; + ptr_t current_addr, limit; + int i; +int dummy; + + BZERO(GC_grungy_pages, (sizeof GC_grungy_pages)); + + bufp = GC_proc_buf; + if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) { +# ifdef PRINTSTATS + GC_printf1("/proc read failed: GC_proc_buf_size = %lu\n", + GC_proc_buf_size); +# endif + { + /* Retry with larger buffer. */ + word new_size = 2 * GC_proc_buf_size; + char * new_buf = GC_scratch_alloc(new_size); + + if (new_buf != 0) { + GC_proc_buf = bufp = new_buf; + GC_proc_buf_size = new_size; + } + if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) { + WARN("Insufficient space for /proc read\n", 0); + /* Punt: */ + memset(GC_grungy_pages, 0xff, sizeof (page_hash_table)); + memset(GC_written_pages, 0xff, sizeof(page_hash_table)); +# ifdef GC_SOLARIS_THREADS + BZERO(GC_fresh_pages, + MAX_FRESH_PAGES * sizeof (struct hblk *)); +# endif + return; + } + } + } + /* Copy dirty bits into GC_grungy_pages */ + nmaps = ((struct prpageheader *)bufp) -> pr_nmap; + /* printf( "nmaps = %d, PG_REFERENCED = %d, PG_MODIFIED = %d\n", + nmaps, PG_REFERENCED, PG_MODIFIED); */ + bufp = bufp + sizeof(struct prpageheader); + for (i = 0; i < nmaps; i++) { + map = (struct prasmap *)bufp; + vaddr = (ptr_t)(map -> pr_vaddr); + ps = map -> pr_pagesize; + np = map -> pr_npage; + /* printf("vaddr = 0x%X, ps = 0x%X, np = 0x%X\n", vaddr, ps, np); */ + limit = vaddr + ps * np; + bufp += sizeof (struct prasmap); + for (current_addr = vaddr; + current_addr < limit; current_addr += ps){ + if ((*bufp++) & PG_MODIFIED) { + register struct hblk * h = (struct hblk *) current_addr; + + while ((ptr_t)h < current_addr + ps) { + register word index = PHT_HASH(h); + + set_pht_entry_from_index(GC_grungy_pages, index); +# ifdef GC_SOLARIS_THREADS + { + register int slot = FRESH_PAGE_SLOT(h); + + if (GC_fresh_pages[slot] == h) { + GC_fresh_pages[slot] = 0; + } + } +# endif + h++; + } + } + } + bufp += sizeof(long) - 1; + bufp = (char *)((unsigned long)bufp & ~(sizeof(long)-1)); + } + /* Update GC_written_pages. */ + GC_or_pages(GC_written_pages, GC_grungy_pages); +# ifdef GC_SOLARIS_THREADS + /* Make sure that old stacks are considered completely clean */ + /* unless written again. */ + GC_old_stacks_are_fresh(); +# endif +} + +#undef READ + +GC_bool GC_page_was_dirty(h) +struct hblk *h; +{ + register word index = PHT_HASH(h); + register GC_bool result; + + result = get_pht_entry_from_index(GC_grungy_pages, index); +# ifdef GC_SOLARIS_THREADS + if (result && PAGE_IS_FRESH(h)) result = FALSE; + /* This happens only if page was declared fresh since */ + /* the read_dirty call, e.g. because it's in an unused */ + /* thread stack. It's OK to treat it as clean, in */ + /* that case. And it's consistent with */ + /* GC_page_was_ever_dirty. */ +# endif + return(result); +} + +GC_bool GC_page_was_ever_dirty(h) +struct hblk *h; +{ + register word index = PHT_HASH(h); + register GC_bool result; + + result = get_pht_entry_from_index(GC_written_pages, index); +# ifdef GC_SOLARIS_THREADS + if (result && PAGE_IS_FRESH(h)) result = FALSE; +# endif + return(result); +} + +/* Caller holds allocation lock. */ +void GC_is_fresh(h, n) +struct hblk *h; +word n; +{ + + register word index; + +# ifdef GC_SOLARIS_THREADS + register word i; + + if (GC_fresh_pages != 0) { + for (i = 0; i < n; i++) { + ADD_FRESH_PAGE(h + i); + } + } +# endif +} + +# endif /* PROC_VDB */ + + +# ifdef PCR_VDB + +# include "vd/PCR_VD.h" + +# define NPAGES (32*1024) /* 128 MB */ + +PCR_VD_DB GC_grungy_bits[NPAGES]; + +ptr_t GC_vd_base; /* Address corresponding to GC_grungy_bits[0] */ + /* HBLKSIZE aligned. */ + +void GC_dirty_init() +{ + GC_dirty_maintained = TRUE; + /* For the time being, we assume the heap generally grows up */ + GC_vd_base = GC_heap_sects[0].hs_start; + if (GC_vd_base == 0) { + ABORT("Bad initial heap segment"); + } + if (PCR_VD_Start(HBLKSIZE, GC_vd_base, NPAGES*HBLKSIZE) + != PCR_ERes_okay) { + ABORT("dirty bit initialization failed"); + } +} + +void GC_read_dirty() +{ + /* lazily enable dirty bits on newly added heap sects */ + { + static int onhs = 0; + int nhs = GC_n_heap_sects; + for( ; onhs < nhs; onhs++ ) { + PCR_VD_WriteProtectEnable( + GC_heap_sects[onhs].hs_start, + GC_heap_sects[onhs].hs_bytes ); + } + } + + + if (PCR_VD_Clear(GC_vd_base, NPAGES*HBLKSIZE, GC_grungy_bits) + != PCR_ERes_okay) { + ABORT("dirty bit read failed"); + } +} + +GC_bool GC_page_was_dirty(h) +struct hblk *h; +{ + if((ptr_t)h < GC_vd_base || (ptr_t)h >= GC_vd_base + NPAGES*HBLKSIZE) { + return(TRUE); + } + return(GC_grungy_bits[h - (struct hblk *)GC_vd_base] & PCR_VD_DB_dirtyBit); +} + +/*ARGSUSED*/ +void GC_remove_protection(h, nblocks, is_ptrfree) +struct hblk *h; +word nblocks; +GC_bool is_ptrfree; +{ + PCR_VD_WriteProtectDisable(h, nblocks*HBLKSIZE); + PCR_VD_WriteProtectEnable(h, nblocks*HBLKSIZE); +} + +# endif /* PCR_VDB */ + +#if defined(MPROTECT_VDB) && defined(DARWIN) +/* The following sources were used as a *reference* for this exception handling + code: + 1. Apple's mach/xnu documentation + 2. Timothy J. Wood's "Mach Exception Handlers 101" post to the + omnigroup's macosx-dev list. + www.omnigroup.com/mailman/archive/macosx-dev/2000-June/014178.html + 3. macosx-nat.c from Apple's GDB source code. +*/ + +/* The bug that caused all this trouble should now be fixed. This should + eventually be removed if all goes well. */ +/* define BROKEN_EXCEPTION_HANDLING */ + +#include <mach/mach.h> +#include <mach/mach_error.h> +#include <mach/thread_status.h> +#include <mach/exception.h> +#include <mach/task.h> +#include <pthread.h> + +/* These are not defined in any header, although they are documented */ +extern boolean_t exc_server(mach_msg_header_t *,mach_msg_header_t *); +extern kern_return_t exception_raise( + mach_port_t,mach_port_t,mach_port_t, + exception_type_t,exception_data_t,mach_msg_type_number_t); +extern kern_return_t exception_raise_state( + mach_port_t,mach_port_t,mach_port_t, + exception_type_t,exception_data_t,mach_msg_type_number_t, + thread_state_flavor_t*,thread_state_t,mach_msg_type_number_t, + thread_state_t,mach_msg_type_number_t*); +extern kern_return_t exception_raise_state_identity( + mach_port_t,mach_port_t,mach_port_t, + exception_type_t,exception_data_t,mach_msg_type_number_t, + thread_state_flavor_t*,thread_state_t,mach_msg_type_number_t, + thread_state_t,mach_msg_type_number_t*); + + +#define MAX_EXCEPTION_PORTS 16 + +static struct { + mach_msg_type_number_t count; + exception_mask_t masks[MAX_EXCEPTION_PORTS]; + exception_handler_t ports[MAX_EXCEPTION_PORTS]; + exception_behavior_t behaviors[MAX_EXCEPTION_PORTS]; + thread_state_flavor_t flavors[MAX_EXCEPTION_PORTS]; +} GC_old_exc_ports; + +static struct { + mach_port_t exception; +#if defined(THREADS) + mach_port_t reply; +#endif +} GC_ports; + +typedef struct { + mach_msg_header_t head; +} GC_msg_t; + +typedef enum { + GC_MP_NORMAL, GC_MP_DISCARDING, GC_MP_STOPPED +} GC_mprotect_state_t; + +/* FIXME: 1 and 2 seem to be safe to use in the msgh_id field, + but it isn't documented. Use the source and see if they + should be ok. */ +#define ID_STOP 1 +#define ID_RESUME 2 + +/* These values are only used on the reply port */ +#define ID_ACK 3 + +#if defined(THREADS) + +GC_mprotect_state_t GC_mprotect_state; + +/* The following should ONLY be called when the world is stopped */ +static void GC_mprotect_thread_notify(mach_msg_id_t id) { + struct { + GC_msg_t msg; + mach_msg_trailer_t trailer; + } buf; + mach_msg_return_t r; + /* remote, local */ + buf.msg.head.msgh_bits = + MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND,0); + buf.msg.head.msgh_size = sizeof(buf.msg); + buf.msg.head.msgh_remote_port = GC_ports.exception; + buf.msg.head.msgh_local_port = MACH_PORT_NULL; + buf.msg.head.msgh_id = id; + + r = mach_msg( + &buf.msg.head, + MACH_SEND_MSG|MACH_RCV_MSG|MACH_RCV_LARGE, + sizeof(buf.msg), + sizeof(buf), + GC_ports.reply, + MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + if(r != MACH_MSG_SUCCESS) + ABORT("mach_msg failed in GC_mprotect_thread_notify"); + if(buf.msg.head.msgh_id != ID_ACK) + ABORT("invalid ack in GC_mprotect_thread_notify"); +} + +/* Should only be called by the mprotect thread */ +static void GC_mprotect_thread_reply() { + GC_msg_t msg; + mach_msg_return_t r; + /* remote, local */ + msg.head.msgh_bits = + MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND,0); + msg.head.msgh_size = sizeof(msg); + msg.head.msgh_remote_port = GC_ports.reply; + msg.head.msgh_local_port = MACH_PORT_NULL; + msg.head.msgh_id = ID_ACK; + + r = mach_msg( + &msg.head, + MACH_SEND_MSG, + sizeof(msg), + 0, + MACH_PORT_NULL, + MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + if(r != MACH_MSG_SUCCESS) + ABORT("mach_msg failed in GC_mprotect_thread_reply"); +} + +void GC_mprotect_stop() { + GC_mprotect_thread_notify(ID_STOP); +} +void GC_mprotect_resume() { + GC_mprotect_thread_notify(ID_RESUME); +} + +#else /* !THREADS */ +/* The compiler should optimize away any GC_mprotect_state computations */ +#define GC_mprotect_state GC_MP_NORMAL +#endif + +static void *GC_mprotect_thread(void *arg) { + mach_msg_return_t r; + /* These two structures contain some private kernel data. We don't need to + access any of it so we don't bother defining a proper struct. The + correct definitions are in the xnu source code. */ + struct { + mach_msg_header_t head; + char data[256]; + } reply; + struct { + mach_msg_header_t head; + mach_msg_body_t msgh_body; + char data[1024]; + } msg; + + mach_msg_id_t id; + + GC_darwin_register_mach_handler_thread(mach_thread_self()); + + for(;;) { + r = mach_msg( + &msg.head, + MACH_RCV_MSG|MACH_RCV_LARGE| + (GC_mprotect_state == GC_MP_DISCARDING ? MACH_RCV_TIMEOUT : 0), + 0, + sizeof(msg), + GC_ports.exception, + GC_mprotect_state == GC_MP_DISCARDING ? 0 : MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + + id = r == MACH_MSG_SUCCESS ? msg.head.msgh_id : -1; + +#if defined(THREADS) + if(GC_mprotect_state == GC_MP_DISCARDING) { + if(r == MACH_RCV_TIMED_OUT) { + GC_mprotect_state = GC_MP_STOPPED; + GC_mprotect_thread_reply(); + continue; + } + if(r == MACH_MSG_SUCCESS && (id == ID_STOP || id == ID_RESUME)) + ABORT("out of order mprotect thread request"); + } +#endif + + if(r != MACH_MSG_SUCCESS) { + GC_err_printf2("mach_msg failed with %d %s\n", + (int)r,mach_error_string(r)); + ABORT("mach_msg failed"); + } + + switch(id) { +#if defined(THREADS) + case ID_STOP: + if(GC_mprotect_state != GC_MP_NORMAL) + ABORT("Called mprotect_stop when state wasn't normal"); + GC_mprotect_state = GC_MP_DISCARDING; + break; + case ID_RESUME: + if(GC_mprotect_state != GC_MP_STOPPED) + ABORT("Called mprotect_resume when state wasn't stopped"); + GC_mprotect_state = GC_MP_NORMAL; + GC_mprotect_thread_reply(); + break; +#endif /* THREADS */ + default: + /* Handle the message (calls catch_exception_raise) */ + if(!exc_server(&msg.head,&reply.head)) + ABORT("exc_server failed"); + /* Send the reply */ + r = mach_msg( + &reply.head, + MACH_SEND_MSG, + reply.head.msgh_size, + 0, + MACH_PORT_NULL, + MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + if(r != MACH_MSG_SUCCESS) { + /* This will fail if the thread dies, but the thread shouldn't + die... */ + #ifdef BROKEN_EXCEPTION_HANDLING + GC_err_printf2( + "mach_msg failed with %d %s while sending exc reply\n", + (int)r,mach_error_string(r)); + #else + ABORT("mach_msg failed while sending exception reply"); + #endif + } + } /* switch */ + } /* for(;;) */ + /* NOT REACHED */ + return NULL; +} + +/* All this SIGBUS code shouldn't be necessary. All protection faults should + be going throught the mach exception handler. However, it seems a SIGBUS is + occasionally sent for some unknown reason. Even more odd, it seems to be + meaningless and safe to ignore. */ +#ifdef BROKEN_EXCEPTION_HANDLING + +typedef void (* SIG_PF)(); +static SIG_PF GC_old_bus_handler; + +/* Updates to this aren't atomic, but the SIGBUSs seem pretty rare. + Even if this doesn't get updated property, it isn't really a problem */ +static int GC_sigbus_count; + +static void GC_darwin_sigbus(int num,siginfo_t *sip,void *context) { + if(num != SIGBUS) ABORT("Got a non-sigbus signal in the sigbus handler"); + + /* Ugh... some seem safe to ignore, but too many in a row probably means + trouble. GC_sigbus_count is reset for each mach exception that is + handled */ + if(GC_sigbus_count >= 8) { + ABORT("Got more than 8 SIGBUSs in a row!"); + } else { + GC_sigbus_count++; + GC_err_printf0("GC: WARNING: Ignoring SIGBUS.\n"); + } +} +#endif /* BROKEN_EXCEPTION_HANDLING */ + +void GC_dirty_init() { + kern_return_t r; + mach_port_t me; + pthread_t thread; + pthread_attr_t attr; + exception_mask_t mask; + +# ifdef PRINTSTATS + GC_printf0("Inititalizing mach/darwin mprotect virtual dirty bit " + "implementation\n"); +# endif +# ifdef BROKEN_EXCEPTION_HANDLING + GC_err_printf0("GC: WARNING: Enabling workarounds for various darwin " + "exception handling bugs.\n"); +# endif + GC_dirty_maintained = TRUE; + if (GC_page_size % HBLKSIZE != 0) { + GC_err_printf0("Page size not multiple of HBLKSIZE\n"); + ABORT("Page size not multiple of HBLKSIZE"); + } + + GC_task_self = me = mach_task_self(); + + r = mach_port_allocate(me,MACH_PORT_RIGHT_RECEIVE,&GC_ports.exception); + if(r != KERN_SUCCESS) ABORT("mach_port_allocate failed (exception port)"); + + r = mach_port_insert_right(me,GC_ports.exception,GC_ports.exception, + MACH_MSG_TYPE_MAKE_SEND); + if(r != KERN_SUCCESS) + ABORT("mach_port_insert_right failed (exception port)"); + + #if defined(THREADS) + r = mach_port_allocate(me,MACH_PORT_RIGHT_RECEIVE,&GC_ports.reply); + if(r != KERN_SUCCESS) ABORT("mach_port_allocate failed (reply port)"); + #endif + + /* The exceptions we want to catch */ + mask = EXC_MASK_BAD_ACCESS; + + r = task_get_exception_ports( + me, + mask, + GC_old_exc_ports.masks, + &GC_old_exc_ports.count, + GC_old_exc_ports.ports, + GC_old_exc_ports.behaviors, + GC_old_exc_ports.flavors + ); + if(r != KERN_SUCCESS) ABORT("task_get_exception_ports failed"); + + r = task_set_exception_ports( + me, + mask, + GC_ports.exception, + EXCEPTION_DEFAULT, + GC_MACH_THREAD_STATE + ); + if(r != KERN_SUCCESS) ABORT("task_set_exception_ports failed"); + + if(pthread_attr_init(&attr) != 0) ABORT("pthread_attr_init failed"); + if(pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED) != 0) + ABORT("pthread_attr_setdetachedstate failed"); + +# undef pthread_create + /* This will call the real pthread function, not our wrapper */ + if(pthread_create(&thread,&attr,GC_mprotect_thread,NULL) != 0) + ABORT("pthread_create failed"); + pthread_attr_destroy(&attr); + + /* Setup the sigbus handler for ignoring the meaningless SIGBUSs */ + #ifdef BROKEN_EXCEPTION_HANDLING + { + struct sigaction sa, oldsa; + sa.sa_handler = (SIG_PF)GC_darwin_sigbus; + sigemptyset(&sa.sa_mask); + sa.sa_flags = SA_RESTART|SA_SIGINFO; + if(sigaction(SIGBUS,&sa,&oldsa) < 0) ABORT("sigaction"); + GC_old_bus_handler = (SIG_PF)oldsa.sa_handler; + if (GC_old_bus_handler != SIG_DFL) { +# ifdef PRINTSTATS + GC_err_printf0("Replaced other SIGBUS handler\n"); +# endif + } + } + #endif /* BROKEN_EXCEPTION_HANDLING */ +} + +/* The source code for Apple's GDB was used as a reference for the exception + forwarding code. This code is similar to be GDB code only because there is + only one way to do it. */ +static kern_return_t GC_forward_exception( + mach_port_t thread, + mach_port_t task, + exception_type_t exception, + exception_data_t data, + mach_msg_type_number_t data_count +) { + int i; + kern_return_t r; + mach_port_t port; + exception_behavior_t behavior; + thread_state_flavor_t flavor; + + thread_state_t thread_state; + mach_msg_type_number_t thread_state_count = THREAD_STATE_MAX; + + for(i=0;i<GC_old_exc_ports.count;i++) + if(GC_old_exc_ports.masks[i] & (1 << exception)) + break; + if(i==GC_old_exc_ports.count) ABORT("No handler for exception!"); + + port = GC_old_exc_ports.ports[i]; + behavior = GC_old_exc_ports.behaviors[i]; + flavor = GC_old_exc_ports.flavors[i]; + + if(behavior != EXCEPTION_DEFAULT) { + r = thread_get_state(thread,flavor,thread_state,&thread_state_count); + if(r != KERN_SUCCESS) + ABORT("thread_get_state failed in forward_exception"); + } + + switch(behavior) { + case EXCEPTION_DEFAULT: + r = exception_raise(port,thread,task,exception,data,data_count); + break; + case EXCEPTION_STATE: + r = exception_raise_state(port,thread,task,exception,data, + data_count,&flavor,thread_state,thread_state_count, + thread_state,&thread_state_count); + break; + case EXCEPTION_STATE_IDENTITY: + r = exception_raise_state_identity(port,thread,task,exception,data, + data_count,&flavor,thread_state,thread_state_count, + thread_state,&thread_state_count); + break; + default: + r = KERN_FAILURE; /* make gcc happy */ + ABORT("forward_exception: unknown behavior"); + break; + } + + if(behavior != EXCEPTION_DEFAULT) { + r = thread_set_state(thread,flavor,thread_state,thread_state_count); + if(r != KERN_SUCCESS) + ABORT("thread_set_state failed in forward_exception"); + } + + return r; +} + +#define FWD() GC_forward_exception(thread,task,exception,code,code_count) + +/* This violates the namespace rules but there isn't anything that can be done + about it. The exception handling stuff is hard coded to call this */ +kern_return_t +catch_exception_raise( + mach_port_t exception_port,mach_port_t thread,mach_port_t task, + exception_type_t exception,exception_data_t code, + mach_msg_type_number_t code_count +) { + kern_return_t r; + char *addr; + struct hblk *h; + int i; +# if defined(POWERPC) +# if CPP_WORDSZ == 32 + thread_state_flavor_t flavor = PPC_EXCEPTION_STATE; + mach_msg_type_number_t exc_state_count = PPC_EXCEPTION_STATE_COUNT; + ppc_exception_state_t exc_state; +# else + thread_state_flavor_t flavor = PPC_EXCEPTION_STATE64; + mach_msg_type_number_t exc_state_count = PPC_EXCEPTION_STATE64_COUNT; + ppc_exception_state64_t exc_state; +# endif +# elif defined(I386) || defined(X86_64) +# if CPP_WORDSZ == 32 + thread_state_flavor_t flavor = x86_EXCEPTION_STATE32; + mach_msg_type_number_t exc_state_count = x86_EXCEPTION_STATE32_COUNT; + x86_exception_state32_t exc_state; +# else + thread_state_flavor_t flavor = x86_EXCEPTION_STATE64; + mach_msg_type_number_t exc_state_count = x86_EXCEPTION_STATE64_COUNT; + x86_exception_state64_t exc_state; +# endif +# else +# error FIXME for non-ppc darwin +# endif + + + if(exception != EXC_BAD_ACCESS || code[0] != KERN_PROTECTION_FAILURE) { + #ifdef DEBUG_EXCEPTION_HANDLING + /* We aren't interested, pass it on to the old handler */ + GC_printf3("Exception: 0x%x Code: 0x%x 0x%x in catch....\n", + exception, + code_count > 0 ? code[0] : -1, + code_count > 1 ? code[1] : -1); + #endif + return FWD(); + } + + r = thread_get_state(thread,flavor, + (natural_t*)&exc_state,&exc_state_count); + if(r != KERN_SUCCESS) { + /* The thread is supposed to be suspended while the exception handler + is called. This shouldn't fail. */ + #ifdef BROKEN_EXCEPTION_HANDLING + GC_err_printf0("thread_get_state failed in " + "catch_exception_raise\n"); + return KERN_SUCCESS; + #else + ABORT("thread_get_state failed in catch_exception_raise"); + #endif + } + + /* This is the address that caused the fault */ +#if defined(POWERPC) + addr = (char*) exc_state. THREAD_FLD(dar); +#elif defined (I386) || defined (X86_64) + addr = (char*) exc_state. THREAD_FLD(faultvaddr); +#else +# error FIXME for non POWERPC/I386 +#endif + + if((HDR(addr)) == 0) { + /* Ugh... just like the SIGBUS problem above, it seems we get a bogus + KERN_PROTECTION_FAILURE every once and a while. We wait till we get + a bunch in a row before doing anything about it. If a "real" fault + ever occurres it'll just keep faulting over and over and we'll hit + the limit pretty quickly. */ + #ifdef BROKEN_EXCEPTION_HANDLING + static char *last_fault; + static int last_fault_count; + + if(addr != last_fault) { + last_fault = addr; + last_fault_count = 0; + } + if(++last_fault_count < 32) { + if(last_fault_count == 1) + GC_err_printf1( + "GC: WARNING: Ignoring KERN_PROTECTION_FAILURE at %p\n", + addr); + return KERN_SUCCESS; + } + + GC_err_printf1("Unexpected KERN_PROTECTION_FAILURE at %p\n",addr); + /* Can't pass it along to the signal handler because that is + ignoring SIGBUS signals. We also shouldn't call ABORT here as + signals don't always work too well from the exception handler. */ + GC_err_printf0("Aborting\n"); + exit(EXIT_FAILURE); + #else /* BROKEN_EXCEPTION_HANDLING */ + /* Pass it along to the next exception handler + (which should call SIGBUS/SIGSEGV) */ + return FWD(); + #endif /* !BROKEN_EXCEPTION_HANDLING */ + } + + #ifdef BROKEN_EXCEPTION_HANDLING + /* Reset the number of consecutive SIGBUSs */ + GC_sigbus_count = 0; + #endif + + if(GC_mprotect_state == GC_MP_NORMAL) { /* common case */ + h = (struct hblk*)((word)addr & ~(GC_page_size-1)); + UNPROTECT(h, GC_page_size); + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + register int index = PHT_HASH(h+i); + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + } else if(GC_mprotect_state == GC_MP_DISCARDING) { + /* Lie to the thread for now. No sense UNPROTECT()ing the memory + when we're just going to PROTECT() it again later. The thread + will just fault again once it resumes */ + } else { + /* Shouldn't happen, i don't think */ + GC_printf0("KERN_PROTECTION_FAILURE while world is stopped\n"); + return FWD(); + } + return KERN_SUCCESS; +} +#undef FWD + +/* These should never be called, but just in case... */ +kern_return_t catch_exception_raise_state(mach_port_name_t exception_port, + int exception, exception_data_t code, mach_msg_type_number_t codeCnt, + int flavor, thread_state_t old_state, int old_stateCnt, + thread_state_t new_state, int new_stateCnt) +{ + ABORT("catch_exception_raise_state"); + return(KERN_INVALID_ARGUMENT); +} +kern_return_t catch_exception_raise_state_identity( + mach_port_name_t exception_port, mach_port_t thread, mach_port_t task, + int exception, exception_data_t code, mach_msg_type_number_t codeCnt, + int flavor, thread_state_t old_state, int old_stateCnt, + thread_state_t new_state, int new_stateCnt) +{ + ABORT("catch_exception_raise_state_identity"); + return(KERN_INVALID_ARGUMENT); +} + + +#endif /* DARWIN && MPROTECT_VDB */ + +# ifndef HAVE_INCREMENTAL_PROTECTION_NEEDS + int GC_incremental_protection_needs() + { + return GC_PROTECTS_NONE; + } +# endif /* !HAVE_INCREMENTAL_PROTECTION_NEEDS */ + +/* + * Call stack save code for debugging. + * Should probably be in mach_dep.c, but that requires reorganization. + */ + +/* I suspect the following works for most X86 *nix variants, so */ +/* long as the frame pointer is explicitly stored. In the case of gcc, */ +/* compiler flags (e.g. -fomit-frame-pointer) determine whether it is. */ +#if defined(I386) && defined(LINUX) && defined(SAVE_CALL_CHAIN) +# include <features.h> + + struct frame { + struct frame *fr_savfp; + long fr_savpc; + long fr_arg[NARGS]; /* All the arguments go here. */ + }; +#endif + +#if defined(SPARC) +# if defined(LINUX) +# include <features.h> + + struct frame { + long fr_local[8]; + long fr_arg[6]; + struct frame *fr_savfp; + long fr_savpc; +# ifndef __arch64__ + char *fr_stret; +# endif + long fr_argd[6]; + long fr_argx[0]; + }; +# else +# if defined(SUNOS4) +# include <machine/frame.h> +# else +# if defined (DRSNX) +# include <sys/sparc/frame.h> +# else +# if defined(OPENBSD) +# include <frame.h> +# else +# if defined(FREEBSD) || defined(NETBSD) +# include <machine/frame.h> +# else +# include <sys/frame.h> +# endif +# endif +# endif +# endif +# endif +# if NARGS > 6 + --> We only know how to to get the first 6 arguments +# endif +#endif /* SPARC */ + +#ifdef NEED_CALLINFO +/* Fill in the pc and argument information for up to NFRAMES of my */ +/* callers. Ignore my frame and my callers frame. */ + +#ifdef LINUX +# include <unistd.h> +#endif + +#endif /* NEED_CALLINFO */ + +#if defined(GC_HAVE_BUILTIN_BACKTRACE) +# include <execinfo.h> +#endif + +#ifdef SAVE_CALL_CHAIN + +#if NARGS == 0 && NFRAMES % 2 == 0 /* No padding */ \ + && defined(GC_HAVE_BUILTIN_BACKTRACE) + +#ifdef REDIRECT_MALLOC + /* Deal with possible malloc calls in backtrace by omitting */ + /* the infinitely recursing backtrace. */ +# ifdef THREADS + __thread /* If your compiler doesn't understand this */ + /* you could use something like pthread_getspecific. */ +# endif + GC_in_save_callers = FALSE; +#endif + +void GC_save_callers (info) +struct callinfo info[NFRAMES]; +{ + void * tmp_info[NFRAMES + 1]; + int npcs, i; +# define IGNORE_FRAMES 1 + + /* We retrieve NFRAMES+1 pc values, but discard the first, since it */ + /* points to our own frame. */ +# ifdef REDIRECT_MALLOC + if (GC_in_save_callers) { + info[0].ci_pc = (word)(&GC_save_callers); + for (i = 1; i < NFRAMES; ++i) info[i].ci_pc = 0; + return; + } + GC_in_save_callers = TRUE; +# endif + GC_ASSERT(sizeof(struct callinfo) == sizeof(void *)); + npcs = backtrace((void **)tmp_info, NFRAMES + IGNORE_FRAMES); + BCOPY(tmp_info+IGNORE_FRAMES, info, (npcs - IGNORE_FRAMES) * sizeof(void *)); + for (i = npcs - IGNORE_FRAMES; i < NFRAMES; ++i) info[i].ci_pc = 0; +# ifdef REDIRECT_MALLOC + GC_in_save_callers = FALSE; +# endif +} + +#else /* No builtin backtrace; do it ourselves */ + +#if (defined(OPENBSD) || defined(NETBSD) || defined(FREEBSD)) && defined(SPARC) +# define FR_SAVFP fr_fp +# define FR_SAVPC fr_pc +#else +# define FR_SAVFP fr_savfp +# define FR_SAVPC fr_savpc +#endif + +#if defined(SPARC) && (defined(__arch64__) || defined(__sparcv9)) +# define BIAS 2047 +#else +# define BIAS 0 +#endif + +void GC_save_callers (info) +struct callinfo info[NFRAMES]; +{ + struct frame *frame; + struct frame *fp; + int nframes = 0; +# ifdef I386 + /* We assume this is turned on only with gcc as the compiler. */ + asm("movl %%ebp,%0" : "=r"(frame)); + fp = frame; +# else + frame = (struct frame *) GC_save_regs_in_stack (); + fp = (struct frame *)((long) frame -> FR_SAVFP + BIAS); +#endif + + for (; (!(fp HOTTER_THAN frame) && !(GC_stackbottom HOTTER_THAN (ptr_t)fp) + && (nframes < NFRAMES)); + fp = (struct frame *)((long) fp -> FR_SAVFP + BIAS), nframes++) { + register int i; + + info[nframes].ci_pc = fp->FR_SAVPC; +# if NARGS > 0 + for (i = 0; i < NARGS; i++) { + info[nframes].ci_arg[i] = ~(fp->fr_arg[i]); + } +# endif /* NARGS > 0 */ + } + if (nframes < NFRAMES) info[nframes].ci_pc = 0; +} + +#endif /* No builtin backtrace */ + +#endif /* SAVE_CALL_CHAIN */ + +#ifdef NEED_CALLINFO + +/* Print info to stderr. We do NOT hold the allocation lock */ +void GC_print_callers (info) +struct callinfo info[NFRAMES]; +{ + register int i; + static int reentry_count = 0; + GC_bool stop = FALSE; + + /* FIXME: This should probably use a different lock, so that we */ + /* become callable with or without the allocation lock. */ + LOCK(); + ++reentry_count; + UNLOCK(); + +# if NFRAMES == 1 + GC_err_printf0("\tCaller at allocation:\n"); +# else + GC_err_printf0("\tCall chain at allocation:\n"); +# endif + for (i = 0; i < NFRAMES && !stop ; i++) { + if (info[i].ci_pc == 0) break; +# if NARGS > 0 + { + int j; + + GC_err_printf0("\t\targs: "); + for (j = 0; j < NARGS; j++) { + if (j != 0) GC_err_printf0(", "); + GC_err_printf2("%d (0x%X)", ~(info[i].ci_arg[j]), + ~(info[i].ci_arg[j])); + } + GC_err_printf0("\n"); + } +# endif + if (reentry_count > 1) { + /* We were called during an allocation during */ + /* a previous GC_print_callers call; punt. */ + GC_err_printf1("\t\t##PC##= 0x%lx\n", info[i].ci_pc); + continue; + } + { +# ifdef LINUX + FILE *pipe; +# endif +# if defined(GC_HAVE_BUILTIN_BACKTRACE) \ + && !defined(GC_BACKTRACE_SYMBOLS_BROKEN) + char **sym_name = + backtrace_symbols((void **)(&(info[i].ci_pc)), 1); + char *name = sym_name[0]; +# else + char buf[40]; + char *name = buf; + sprintf(buf, "##PC##= 0x%lx", info[i].ci_pc); +# endif +# if defined(LINUX) && !defined(SMALL_CONFIG) + /* Try for a line number. */ + { +# define EXE_SZ 100 + static char exe_name[EXE_SZ]; +# define CMD_SZ 200 + char cmd_buf[CMD_SZ]; +# define RESULT_SZ 200 + static char result_buf[RESULT_SZ]; + size_t result_len; + char *old_preload; +# define PRELOAD_SZ 200 + char preload_buf[PRELOAD_SZ]; + static GC_bool found_exe_name = FALSE; + static GC_bool will_fail = FALSE; + int ret_code; + /* Try to get it via a hairy and expensive scheme. */ + /* First we get the name of the executable: */ + if (will_fail) goto out; + if (!found_exe_name) { + ret_code = readlink("/proc/self/exe", exe_name, EXE_SZ); + if (ret_code < 0 || ret_code >= EXE_SZ + || exe_name[0] != '/') { + will_fail = TRUE; /* Dont try again. */ + goto out; + } + exe_name[ret_code] = '\0'; + found_exe_name = TRUE; + } + /* Then we use popen to start addr2line -e <exe> <addr> */ + /* There are faster ways to do this, but hopefully this */ + /* isn't time critical. */ + sprintf(cmd_buf, "/usr/bin/addr2line -f -e %s 0x%lx", exe_name, + (unsigned long)info[i].ci_pc); + old_preload = getenv ("LD_PRELOAD"); + if (0 != old_preload) { + if (strlen (old_preload) >= PRELOAD_SZ) { + will_fail = TRUE; + goto out; + } + strcpy (preload_buf, old_preload); + unsetenv ("LD_PRELOAD"); + } + pipe = popen(cmd_buf, "r"); + if (0 != old_preload + && 0 != setenv ("LD_PRELOAD", preload_buf, 0)) { + WARN("Failed to reset LD_PRELOAD\n", 0); + } + if (pipe == NULL + || (result_len = fread(result_buf, 1, RESULT_SZ - 1, pipe)) + == 0) { + if (pipe != NULL) pclose(pipe); + will_fail = TRUE; + goto out; + } + if (result_buf[result_len - 1] == '\n') --result_len; + result_buf[result_len] = 0; + if (result_buf[0] == '?' + || result_buf[result_len-2] == ':' + && result_buf[result_len-1] == '0') { + pclose(pipe); + goto out; + } + /* Get rid of embedded newline, if any. Test for "main" */ + { + char * nl = strchr(result_buf, '\n'); + if (nl != NULL && nl < result_buf + result_len) { + *nl = ':'; + } + if (strncmp(result_buf, "main", nl - result_buf) == 0) { + stop = TRUE; + } + } + if (result_len < RESULT_SZ - 25) { + /* Add in hex address */ + sprintf(result_buf + result_len, " [0x%lx]", + (unsigned long)info[i].ci_pc); + } + name = result_buf; + pclose(pipe); + out:; + } +# endif /* LINUX */ + GC_err_printf1("\t\t%s\n", name); +# if defined(GC_HAVE_BUILTIN_BACKTRACE) \ + && !defined(GC_BACKTRACE_SYMBOLS_BROKEN) + free(sym_name); /* May call GC_free; that's OK */ +# endif + } + } + LOCK(); + --reentry_count; + UNLOCK(); +} + +#endif /* NEED_CALLINFO */ + + + +#if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG) + +/* Dump /proc/self/maps to GC_stderr, to enable looking up names for + addresses in FIND_LEAK output. */ + +static word dump_maps(char *maps) +{ + GC_err_write(maps, strlen(maps)); + return 1; +} + +void GC_print_address_map() +{ + GC_err_printf0("---------- Begin address map ----------\n"); + GC_apply_to_maps(dump_maps); + GC_err_printf0("---------- End address map ----------\n"); +} + +#endif + + |