Read the shared library cache relative to $ORIGIN instead of reading
from /etc/ld.so.cache. Also arrange so that this cache takes
precedence over RUNPATH.
diff --git a/elf/dl-cache.c b/elf/dl-cache.c
index 93d185e788..e0760a1f40 100644
--- a/elf/dl-cache.c
+++ b/elf/dl-cache.c
@@ -171,6 +171,52 @@ _dl_cache_libcmp (const char *p1, const char *p2)
return *p1 - *p2;
}
+/* Special value representing the lack of an ld.so cache. */
+static const char ld_so_cache_lacking[] = "/ld.so cache is lacking";
+
+/* Return the per-application ld.so cache, relative to $ORIGIN, or NULL if
+ that fails for some reason. Do not return the system-wide LD_SO_CACHE
+ since on a foreign distro it would contain invalid information. */
+static const char *
+ld_so_cache (void)
+{
+ static const char *loader_cache;
+
+ if (loader_cache == NULL)
+ {
+ static const char store[] = @STORE_DIRECTORY@;
+ const char *origin = _dl_get_origin ();
+
+ /* Check whether ORIGIN is something like "/gnu/store/…-foo/bin". */
+ if (origin != (char *) -1 /* _dl_get_origin reported failure */
+ && strncmp (store, origin, strlen (store)) == 0
+ && origin[sizeof store - 1] == '/')
+ {
+ char *store_item_end = strchr (origin + sizeof store, '/');
+
+ if (store_item_end != NULL)
+ {
+ static const char suffix[] = "/etc/ld.so.cache";
+ size_t store_item_len = store_item_end - origin;
+
+ /* Note: We can't use 'malloc' because it can be interposed.
+ Likewise, 'strncpy' is not available. */
+ char *cache = alloca (strlen (origin) + sizeof suffix);
+
+ strcpy (cache, origin);
+ strcpy (cache + store_item_len, suffix);
+
+ loader_cache = __strdup (cache) ?: ld_so_cache_lacking;
+ }
+ else
+ loader_cache = ld_so_cache_lacking;
+ }
+ else
+ loader_cache = ld_so_cache_lacking;
+ }
+
+ return loader_cache;
+}
/* Look up NAME in ld.so.cache and return the file name stored there, or null
if none is found. The cache is loaded if it was not already. If loading
@@ -190,12 +235,15 @@ _dl_load_cache_lookup (const char *name)
/* Print a message if the loading of libs is traced. */
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
- _dl_debug_printf (" search cache=%s\n", LD_SO_CACHE);
+ _dl_debug_printf (" search cache=%s\n", ld_so_cache ());
+
+ if (__glibc_unlikely (ld_so_cache () == ld_so_cache_lacking))
+ return NULL;
if (cache == NULL)
{
/* Read the contents of the file. */
- void *file = _dl_sysdep_read_whole_file (LD_SO_CACHE, &cachesize,
+ void *file = _dl_sysdep_read_whole_file (ld_so_cache (), &cachesize,
PROT_READ);
/* We can handle three different cache file formats here:
diff --git a/elf/dl-load.c b/elf/dl-load.c
index f3201e7c14..a69aec3428 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2152,28 +2152,6 @@ _dl_map_object (struct link_map *loader, const char *name,
loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
LA_SER_LIBPATH, &found_other_class);
- /* Look at the RUNPATH information for this binary. */
- if (fd == -1 && loader != NULL
- && cache_rpath (loader, &loader->l_runpath_dirs,
- DT_RUNPATH, "RUNPATH"))
- fd = open_path (name, namelen, mode,
- &loader->l_runpath_dirs, &realname, &fb, loader,
- LA_SER_RUNPATH, &found_other_class);
-
- if (fd == -1)
- {
- realname = _dl_sysdep_open_object (name, namelen, &fd);
- if (realname != NULL)
- {
- fd = open_verify (realname, fd,
- &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded,
- LA_SER_CONFIG, mode, &found_other_class,
- false);
- if (fd == -1)
- free (realname);
- }
- }
-
#ifdef USE_LDCONFIG
if (fd == -1
&& (__glibc_likely ((mode & __RTLD_SECURE) == 0)
@@ -2232,6 +2210,28 @@ _dl_map_object (struct link_map *loader, const char *name,
}
#endif
+ /* Look at the RUNPATH information for this binary. */
+ if (fd == -1 && loader != NULL
+ && cache_rpath (loader, &loader->l_runpath_dirs,
+ DT_RUNPATH, "RUNPATH"))
+ fd = open_path (name, namelen, mode,
+ &loader->l_runpath_dirs, &realname, &fb, loader,
+ LA_SER_RUNPATH, &found_other_class);
+
+ if (fd == -1)
+ {
+ realname = _dl_sysdep_open_object (name, namelen, &fd);
+ if (realname != NULL)
+ {
+ fd = open_verify (realname, fd,
+ &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded,
+ LA_SER_CONFIG, mode, &found_other_class,
+ false);
+ if (fd == -1)
+ free (realname);
+ }
+ }
+
/* Finally, try the default path. */
if (fd == -1
&& ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL
