internals: -shared/-static heuristics: added slbt_get_lconf_flags().

2 files changed, 198 insertions, 0 deletions

diff --git a/src/internal/slibtool_lconf_impl.c b/src/internal/slibtool_lconf_impl.c
new file mode 100644
index 0000000..9daba91
--- /dev/null
+++ b/src/internal/slibtool_lconf_impl.c
@@ -0,0 +1,185 @@
+/*******************************************************************/
+/*  slibtool: a skinny libtool implementation, written in C        */
+/*  Copyright (C) 2016--2018  Z. Gilboa                            */
+/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */
+/*******************************************************************/
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include "slibtool_lconf_impl.h"
+#include "slibtool_driver_impl.h"
+#include "slibtool_errinfo_impl.h"
+#include "slibtool_symlink_impl.h"
+#include "slibtool_readlink_impl.h"
+
+enum slbt_lconf_opt {
+	SLBT_LCONF_OPT_UNKNOWN,
+	SLBT_LCONF_OPT_NO,
+	SLBT_LCONF_OPT_YES,
+};
+
+static void slbt_lconf_close(int fdcwd, int fdlconfdir)
+{
+	if (fdlconfdir != fdcwd)
+		close(fdlconfdir);
+}
+
+static int slbt_lconf_open(
+	struct slbt_driver_ctx *	dctx,
+	const char *			lconf)
+{
+	int		fdcwd;
+	int		fdlconf;
+	int		fdlconfdir;
+	int		fdparent;
+	struct stat	stcwd;
+	struct stat	stparent;
+
+	fdcwd      = slbt_driver_fdcwd(dctx);
+	fdlconfdir = fdcwd;
+
+	if (lconf)
+		return ((fdlconf = openat(fdcwd,lconf,O_RDONLY,0)) < 0)
+			? SLBT_CUSTOM_ERROR(dctx,SLBT_ERR_LCONF_OPEN)
+			: fdlconf;
+
+	if (fstatat(fdlconfdir,".",&stcwd,0) < 0)
+		return SLBT_SYSTEM_ERROR(dctx);
+
+	fdlconf = openat(fdlconfdir,"libtool",O_RDONLY,0);
+
+	while (fdlconf < 0) {
+		fdparent = openat(fdlconfdir,"../",O_DIRECTORY,0);
+		slbt_lconf_close(fdcwd,fdlconfdir);
+
+		if (fdparent < 0)
+			return SLBT_SYSTEM_ERROR(dctx);
+
+		if (fstat(fdparent,&stparent) < 0)
+			return SLBT_SYSTEM_ERROR(dctx);
+
+		if (stparent.st_dev != stcwd.st_dev)
+			return SLBT_CUSTOM_ERROR(
+				dctx,SLBT_ERR_LCONF_OPEN);
+
+		fdlconfdir = fdparent;
+		fdlconf    = openat(fdlconfdir,"libtool",O_RDONLY,0);
+	}
+
+	return fdlconf;
+}
+
+int slbt_get_lconf_flags(
+	struct slbt_driver_ctx *	dctx,
+	const char *			lconf,
+	uint64_t *			flags)
+{
+	int				fdlconf;
+	struct stat			st;
+	void *				addr;
+	const char *			mark;
+	const char *			cap;
+	uint64_t			optshared;
+	uint64_t			optstatic;
+	int				optlenmax;
+	int				optsharedlen;
+	int				optstaticlen;
+	const char *			optsharedstr;
+	const char *			optstaticstr;
+
+	/* open relative libtool script */
+	if ((fdlconf = slbt_lconf_open(dctx,lconf)) < 0)
+		return SLBT_NESTED_ERROR(dctx);
+
+	if (fdlconf < 0)
+		return SLBT_CUSTOM_ERROR(
+			dctx,SLBT_ERR_LCONF_OPEN);
+
+	/* map relative libtool script */
+	if (fstat(fdlconf,&st) < 0)
+		return SLBT_SYSTEM_ERROR(dctx);
+
+	addr = mmap(
+		0,st.st_size,
+		PROT_READ,MAP_SHARED,
+		fdlconf,0);
+
+	close(fdlconf);
+
+	if (addr == MAP_FAILED)
+		return SLBT_CUSTOM_ERROR(
+			dctx,SLBT_ERR_LCONF_MAP);
+
+	mark = addr;
+	cap  = &mark[st.st_size];
+
+	/* hard-coded options in the generated libtool precede the code */
+	if (st.st_size >= (optlenmax = strlen("build_libtool_libs=yes\n")))
+		cap -= optlenmax;
+
+	/* scan */
+	optshared = 0;
+	optstatic = 0;
+
+	optsharedstr = "build_libtool_libs=";
+	optstaticstr = "build_old_libs=";
+
+	optsharedlen = strlen(optsharedstr);
+	optstaticlen = strlen(optstaticstr);
+
+	for (; mark && mark<cap; ) {
+		if (!strncmp(mark,optsharedstr,optsharedlen)) {
+			mark += optsharedlen;
+
+			if ((mark[0]=='n')
+					&& (mark[1]=='o')
+					&& (mark[2]=='\n'))
+				optshared = SLBT_DRIVER_DISABLE_SHARED;
+
+			if ((mark[0]=='y')
+					&& (mark[1]=='e')
+					&& (mark[2]=='s')
+					&& (mark[3]=='\n'))
+				optshared = SLBT_DRIVER_SHARED;
+
+		} if (!strncmp(mark,optstaticstr,optstaticlen)) {
+			mark += optstaticlen;
+
+			if ((mark[0]=='n')
+					&& (mark[1]=='o')
+					&& (mark[2]=='\n'))
+				optstatic = SLBT_DRIVER_DISABLE_STATIC;
+
+			if ((mark[0]=='y')
+					&& (mark[1]=='e')
+					&& (mark[2]=='s')
+					&& (mark[3]=='\n'))
+				optstatic = SLBT_DRIVER_STATIC;
+		}
+
+		if (optshared && optstatic)
+			mark = 0;
+
+		else {
+			for (; (mark<cap) && (*mark!='\n'); )
+				mark++;
+			mark++;
+		}
+	}
+
+	munmap(addr,st.st_size);
+
+	if (!optshared || !optstatic)
+		return SLBT_CUSTOM_ERROR(
+			dctx,SLBT_ERR_LCONF_PARSE);
+
+	*flags = optshared | optstatic;
+
+	return 0;
+}
diff --git a/src/internal/slibtool_lconf_impl.h b/src/internal/slibtool_lconf_impl.h
new file mode 100644
index 0000000..d2bd44c
--- /dev/null
+++ b/src/internal/slibtool_lconf_impl.h
@@ -0,0 +1,13 @@
+#ifndef SLIBTOOL_LCONF_IMPL_H
+#define SLIBTOOL_LCONF_IMPL_H
+
+#include <stdint.h>
+
+struct slbt_driver_ctx;
+
+int slbt_get_lconf_flags(
+	struct slbt_driver_ctx *	dctx,
+	const char *			lconf,
+	uint64_t *			flags);
+
+#endif