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#include <errno.h>
#include "runtime.h"
#include "malloc.h"
#ifndef MAP_ANON
#ifdef MAP_ANONYMOUS
#define MAP_ANON MAP_ANONYMOUS
#else
#define USE_DEV_ZERO
#define MAP_ANON 0
#endif
#endif
#ifdef USE_DEV_ZERO
static int dev_zero = -1;
#endif
void*
runtime_SysAlloc(uintptr n)
{
void *p;
int fd = -1;
mstats.sys += n;
#ifdef USE_DEV_ZERO
if (dev_zero == -1) {
dev_zero = open("/dev/zero", O_RDONLY);
if (dev_zero < 0) {
printf("open /dev/zero: errno=%d\n", errno);
exit(2);
}
}
fd = dev_zero;
#endif
p = runtime_mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, fd, 0);
if (p == MAP_FAILED) {
if(errno == EACCES) {
printf("mmap: access denied\n");
printf("If you're running SELinux, enable execmem for this process.\n");
} else {
printf("mmap: errno=%d\n", errno);
}
exit(2);
}
return p;
}
void
runtime_SysUnused(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call madvise MADV_DONTNEED
}
void
runtime_SysFree(void *v, uintptr n)
{
mstats.sys -= n;
runtime_munmap(v, n);
}
void
runtime_SysMemInit(void)
{
// Code generators assume that references to addresses
// on the first page will fault. Map the page explicitly with
// no permissions, to head off possible bugs like the system
// allocating that page as the virtual address space fills.
// Ignore any error, since other systems might be smart
// enough to never allow anything there.
runtime_mmap(nil, 4096, PROT_NONE, MAP_FIXED|MAP_ANON|MAP_PRIVATE, -1, 0);
}
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