Wed Jul 17 21:53:45 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>

	* elf/Makefile (dl-routines): Add dl-cache.
	* elf/dl-cache.c: New file.
	* elf/dl-load.c (_dl_map_object): Check cache before default path.

1 files changed, 85 insertions, 0 deletions

diff --git a/elf/dl-cache.c b/elf/dl-cache.c
new file mode 100644
index 0000000000..a282d313cf
--- /dev/null
+++ b/elf/dl-cache.c
@@ -0,0 +1,85 @@
+/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
+Copyright (C) 1996 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <link.h>
+#include <sys/mman.h>
+
+/* System-dependent function to read a file's whole contents
+   in the most convenient manner available.  */
+extern void *_dl_sysdep_read_whole_file (const char *filename,
+					 size_t *filesize_ptr,
+					 int mmap_prot);
+
+#define CACHEMAGIC "ld.so-1.7.0"
+
+struct cache_file
+  {
+    char magic[sizeof CACHEMAGIC - 1];
+    unsigned int nlibs;
+    struct
+      {
+	int flags;		/* This is 1 for an ELF library.  */
+	unsigned int key, value; /* String table indices.  */
+      } libs[0];
+  };
+
+/* Look up NAME in ld.so.cache and return the file name stored there,
+   or null if none is found.  */
+
+const char *
+_dl_load_cache_lookup (const char *name)
+{
+  static struct cache_file *cache;
+  static size_t cachesize;
+  unsigned int i;
+
+  if (cache == (void *) -1)
+    /* Previously looked for the cache file and didn't find it.  */
+    return NULL;
+
+  if (cache == NULL)
+    {
+      /* Read the contents of the file.  */
+      void *file = _dl_sysdep_read_whole_file ("/etc/ld.so.cache", &cachesize,
+					       PROT_READ);
+      if (file && cachesize > sizeof *cache &&
+	  !memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1))
+	/* Looks ok.  */
+	cache = file;
+      else
+	{
+	  if (file)
+	    __munmap (file, cachesize);
+	  cache = (void *) -1;
+	  return NULL;
+	}
+    }
+
+  for (i = 0; i < cache->nlibs; ++i)
+    if (cache->libs[i].flags == 1 && /* ELF library entry.  */
+	/* Make sure string table indices are not bogus before using them.  */
+	cache->libs[i].key < cachesize - sizeof *cache &&
+	cache->libs[i].value < cachesize - sizeof *cache &&
+	/* Does the name match?  */
+	! strcmp (name, ((const char *) &cache->libs[cache->nlibs] +
+			 cache->libs[i].key)))
+      return (const char *) &cache->libs[cache->nlibs] + cache->libs[i].value;
+
+  return NULL;
+}