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authorMike Frysinger <vapier@gentoo.org>2009-10-26 02:32:16 -0400
committerMike Frysinger <vapier@gentoo.org>2009-10-26 02:45:04 -0400
commit180958291462f38154916103a6a4bdeb852e6cc3 (patch)
treeb2d1a521f50905b620349bf373722469ce233446 /libsandbox
parenttests: add reverse lookup funcs (diff)
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libsandbox: rewrite RTLD_NEXT handling
The commit 0a539b142f24 tried to fix RTLD_NEXT issues seen under certain kernel/glibc combos, but in reality all it did was force dlopening of the C library for every symbol lookup. So rewrite the code to handle things on the fly as needed -- if RTLD_NEXT returned a bum symbol, load the C library and try again. URL: http://bugs.gentoo.org/202765 URL: http://bugs.gentoo.org/206678 Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'libsandbox')
-rw-r--r--libsandbox/wrappers.c54
1 files changed, 33 insertions, 21 deletions
diff --git a/libsandbox/wrappers.c b/libsandbox/wrappers.c
index 6094f51..f587614 100644
--- a/libsandbox/wrappers.c
+++ b/libsandbox/wrappers.c
@@ -19,33 +19,33 @@
# define USE_RTLD_NEXT
#endif
-static void *libc_handle = NULL;
+static void *libc_handle;
+
+static void load_libc_handle(void)
+{
+ save_errno(); /* #260765 */
+ libc_handle = dlopen(LIBC_VERSION, RTLD_LAZY);
+ restore_errno();
+
+ if (!libc_handle) {
+ fprintf(stderr, "libsandbox: Can't dlopen libc: %s\n",
+ dlerror());
+ exit(EXIT_FAILURE);
+ }
+}
static void *get_dlsym(const char *symname, const char *symver)
{
- void *symaddr = NULL;
+ void *symaddr;
-#if defined(USE_RTLD_NEXT)
- libc_handle = RTLD_NEXT;
+ if (!libc_handle) {
+#ifdef USE_RTLD_NEXT
+ libc_handle = RTLD_NEXT;
+ try_again: ;
+#else
+ load_libc_handle();
#endif
-
- /* Checking for -1UL is significant on hardened!
- * USE_RTLD_NEXT returns it as a sign of being unusable.
- * However using !x or NULL checks does NOT pick it up!
- * That is also why we need to save/restore errno #260765.
- */
-#define INVALID_LIBC_HANDLE(x) (!x || NULL == x || (void *)-1UL == x)
- if (INVALID_LIBC_HANDLE(libc_handle)) {
- save_errno();
- libc_handle = dlopen(LIBC_VERSION, RTLD_LAZY);
- restore_errno();
- if (INVALID_LIBC_HANDLE(libc_handle)) {
- fprintf(stderr, "libsandbox: Can't dlopen libc: %s\n",
- dlerror());
- exit(EXIT_FAILURE);
- }
}
-#undef INVALID_LIBC_HANDLE
if (NULL == symver)
symaddr = dlsym(libc_handle, symname);
@@ -53,6 +53,18 @@ static void *get_dlsym(const char *symname, const char *symver)
symaddr = dlvsym(libc_handle, symname, symver);
if (!symaddr) {
+#ifdef USE_RTLD_NEXT
+ /* Maybe RTLD_NEXT is broken for some screwed up reason as
+ * can be seen with some specific glibc/kernel versions.
+ * Recover dynamically so that we can be deployed easily
+ * via binpkgs and upgrades #202765 #206678
+ */
+ if (libc_handle == RTLD_NEXT) {
+ load_libc_handle();
+ goto try_again;
+ }
+#endif
+
fprintf(stderr, "libsandbox: Can't resolve %s: %s\n",
symname, dlerror());
exit(EXIT_FAILURE);