Fix recursive dlopen.

The ability to recursively call dlopen is useful for malloc
implementations that wish to load other dynamic modules that
implement reentrant/AS-safe functions to use in their own
implementation.

Given that a user malloc implementation may be called by an
ongoing dlopen to allocate memory the user malloc
implementation interrupts dlopen and if it calls dlopen again
that's a reentrant call.

This patch fixes the issues with the ld.so.cache mapping
and the _r_debug assertion which prevent this from working
as expected.

See:
https://sourceware.org/ml/libc-alpha/2014-12/msg00446.html

1 files changed, 19 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 030491a..d83be7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,22 @@
+2015-01-21  Carlos O'Donell  <carlos@redhat.com>
+
+	[BZ #17702]
+	* dlfcn/Makefile (tests): Add tst-rec-dlopen.
+	(modules-names): Add moddummy1 and moddummy2.
+	($(objpfx)tst-rec-dlopen): Define.
+	* dlfcn/moddummy1.c: New file.
+	* dlfcn/moddummy2.c: New file.
+	* dlfcn/tst-rec-dlopen.c: New file.
+	* elf/dl-cache.c (_dl_load_cache_lookup):
+	Return char*. Copy result with alloca/strcpy/strdup.
+	* elf/dl-load.c (_dl_map_object): _dl_load_cached_lookup
+	returns char*. Free cached. If not saving realname
+	free cached.
+	* elf/dl-open.c (dl_open_worker): Do not assert that
+	_r_debug->r_state is RT_CONSISTENT.
+	* sysdeps/generic/ldsodefs.h: _dl_load_cache_lookup
+	returns char*.
+
 2015-01-21  Torvald Riegel  <triegel@redhat.com>
 	    Carlos O'Donell  <carlos@redhat.com>