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authorSiddhesh Poyarekar <siddhesh@redhat.com>2015-07-21 07:14:16 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2015-07-21 07:14:17 +0530
commitd72c2763056b9c0de69886f8f3e6c3ed0aaa6dd4 (patch)
treea947c3e64ac3c37cc01dbea0140174ca8e9e5298 /stdlib
parent530deb962fb9c6ccbcf773051ab89569ae1b7d7e (diff)
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Remove Linuxism from tst-tls-atexit
The tst-tls-atexit test case searches for its module in /proc/PID/maps to verify that it is unloaded, which is a Linux-specific test. This patch makes the test generic by looking for the library in the link map list in the _r_debug structure. Verified that the test continues to succeed on x86_64. There is a bug in the test case where it calls dlclose once again, which is actually incorrect but still manages to unload the DSO thanks to an existing bug in __tls_call_dtors. This will be fixed in a later patch which also fixes up the __cxa_thread_atexit_impl implementation. I have added a FIXME comment to that call momentarily, which I will remove when I fix the problem. * stdlib/tst-tls-atexit-lib.c (do_foo): Rename to reg_dtor. * stdlib/tst-tls-atexit.c: (is_loaded): New function. (spawn_thread): New function. (load): Rename to reg_dtor_and_close. Move dlopen to... (do_test): ... here. Use IS_LOADED to test for its availability.
Diffstat (limited to 'stdlib')
-rw-r--r--stdlib/tst-tls-atexit-lib.c2
-rw-r--r--stdlib/tst-tls-atexit.c96
2 files changed, 55 insertions, 43 deletions
diff --git a/stdlib/tst-tls-atexit-lib.c b/stdlib/tst-tls-atexit-lib.c
index 2945379..2478d80 100644
--- a/stdlib/tst-tls-atexit-lib.c
+++ b/stdlib/tst-tls-atexit-lib.c
@@ -31,7 +31,7 @@ void A_dtor (void *obj)
((A *)obj)->val = obj;
}
-void do_foo (void)
+void reg_dtor (void)
{
static __thread A b;
__cxa_thread_atexit_impl (A_dtor, &b, __dso_handle);
diff --git a/stdlib/tst-tls-atexit.c b/stdlib/tst-tls-atexit.c
index 0c6c499..cea655d 100644
--- a/stdlib/tst-tls-atexit.c
+++ b/stdlib/tst-tls-atexit.c
@@ -16,10 +16,12 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* There are two tests in this test case. The first is implicit where it is
- assumed that the destructor call on exit of the LOAD function does not
- segfault. The other is a verification that after the thread has exited, a
- dlclose will unload the DSO. */
+/* This test dynamically loads a DSO and spawns a thread that subsequently
+ calls into the DSO to register a destructor for an object in the DSO and
+ then calls dlclose on the handle for the DSO. When the thread exits, the
+ DSO should not be unloaded or else the destructor called during thread exit
+ will crash. Further in the main thread, the DSO is opened and closed again,
+ at which point the DSO should be unloaded. */
#include <dlfcn.h>
#include <pthread.h>
@@ -27,44 +29,53 @@
#include <unistd.h>
#include <string.h>
#include <errno.h>
+#include <link.h>
-void *handle;
+#define DSO_NAME "$ORIGIN/tst-tls-atexit-lib.so"
-void *
-load (void *u)
+/* Walk through the map in the _r_debug structure to see if our lib is still
+ loaded. */
+static bool
+is_loaded (void)
{
- handle = dlopen ("$ORIGIN/tst-tls-atexit-lib.so", RTLD_LAZY);
- if (handle == NULL)
- {
- printf ("Unable to load DSO: %s\n", dlerror ());
- return (void *) (uintptr_t) 1;
- }
+ struct link_map *lm = (struct link_map *) _r_debug.r_map;
- void (*foo) (void) = (void (*) (void)) dlsym (handle, "do_foo");
+ for (; lm; lm = lm->l_next)
+ if (lm->l_type == lt_loaded && lm->l_name
+ && strcmp (basename (DSO_NAME), basename (lm->l_name)) == 0)
+ return true;
+ return false;
+}
+
+/* Accept a valid handle returned by DLOPEN, load the reg_dtor symbol to
+ register a destructor and then call dlclose on the handle. The dlclose
+ should not unload the DSO since the destructor has not been called yet. */
+static void *
+reg_dtor_and_close (void *h)
+{
+ void (*reg_dtor) (void) = (void (*) (void)) dlsym (h, "reg_dtor");
- if (foo == NULL)
+ if (reg_dtor == NULL)
{
printf ("Unable to find symbol: %s\n", dlerror ());
- exit (1);
+ return (void *) (uintptr_t) 1;
}
- foo ();
+ reg_dtor ();
- /* This should not unload the DSO. If it does, then the thread exit will
- result in a segfault. */
- dlclose (handle);
+ dlclose (h);
return NULL;
}
static int
-do_test (void)
+spawn_thread (void *h)
{
pthread_t t;
int ret;
void *thr_ret;
- if ((ret = pthread_create (&t, NULL, load, NULL)) != 0)
+ if ((ret = pthread_create (&t, NULL, reg_dtor_and_close, h)) != 0)
{
printf ("pthread_create failed: %s\n", strerror (ret));
return 1;
@@ -79,30 +90,31 @@ do_test (void)
if (thr_ret != NULL)
return 1;
- /* Now this should unload the DSO. */
- dlclose (handle);
-
- /* Run through our maps and ensure that the DSO is unloaded. */
- FILE *f = fopen ("/proc/self/maps", "r");
+ return 0;
+}
- if (f == NULL)
+static int
+do_test (void)
+{
+ /* Load the DSO. */
+ void *h1 = dlopen (DSO_NAME, RTLD_LAZY);
+ if (h1 == NULL)
{
- perror ("Failed to open /proc/self/maps");
- fprintf (stderr, "Skipping verification of DSO unload\n");
- return 0;
+ printf ("h1: Unable to load DSO: %s\n", dlerror ());
+ return 1;
}
- char *line = NULL;
- size_t s = 0;
- while (getline (&line, &s, f) > 0)
- {
- if (strstr (line, "tst-tls-atexit-lib.so"))
- {
- printf ("DSO not unloaded yet:\n%s", line);
- return 1;
- }
- }
- free (line);
+ if (spawn_thread (h1) != 0)
+ return 1;
+
+ /* Now this should unload the DSO. FIXME: This is a bug, calling dlclose
+ like this is actually wrong, but it works because cxa_thread_atexit_impl
+ has a bug which results in dlclose allowing this to work. */
+ dlclose (h1);
+
+ /* Check link maps to ensure that the DSO has unloaded. */
+ if (is_loaded ())
+ return 1;
return 0;
}