Finally get around to implementing pthread_atfork.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@473 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/vg_libpthread.c b/coregrind/vg_libpthread.c
index cca2d88..c3a11b2 100644
--- a/coregrind/vg_libpthread.c
+++ b/coregrind/vg_libpthread.c
@@ -1269,13 +1269,45 @@
MISC
------------------------------------------------ */
+static pthread_mutex_t pthread_atfork_lock
+ = PTHREAD_MUTEX_INITIALIZER;
+
int __pthread_atfork ( void (*prepare)(void),
void (*parent)(void),
void (*child)(void) )
{
- /* We have to do this properly or not at all; faking it isn't an
- option. */
- vgPlain_unimp("__pthread_atfork");
+ int n, res;
+ ForkHandlerEntry entry;
+
+ ensure_valgrind("pthread_atfork");
+ __pthread_mutex_lock(&pthread_atfork_lock);
+
+ /* Fetch old counter */
+ VALGRIND_MAGIC_SEQUENCE(n, -2 /* default */,
+ VG_USERREQ__GET_FHSTACK_USED,
+ 0, 0, 0, 0);
+ my_assert(n >= 0 && n < VG_N_FORKHANDLERSTACK);
+ if (n == VG_N_FORKHANDLERSTACK-1)
+ barf("pthread_atfork: VG_N_FORKHANDLERSTACK is too low; "
+ "increase and recompile");
+
+ /* Add entry */
+ entry.prepare = *prepare;
+ entry.parent = *parent;
+ entry.child = *child;
+ VALGRIND_MAGIC_SEQUENCE(res, -2 /* default */,
+ VG_USERREQ__SET_FHSTACK_ENTRY,
+ n, &entry, 0, 0);
+ my_assert(res == 0);
+
+ /* Bump counter */
+ VALGRIND_MAGIC_SEQUENCE(res, -2 /* default */,
+ VG_USERREQ__SET_FHSTACK_USED,
+ n+1, 0, 0, 0);
+ my_assert(res == 0);
+
+ __pthread_mutex_unlock(&pthread_atfork_lock);
+ return 0;
}
@@ -1560,15 +1592,6 @@
extern
-pid_t __libc_fork(void);
-pid_t __fork(void)
-{
- __my_pthread_testcancel();
- return __libc_fork();
-}
-
-
-extern
pid_t __libc_waitpid(pid_t pid, int *status, int options);
__attribute__((weak))
pid_t waitpid(pid_t pid, int *status, int options)
@@ -1776,6 +1799,80 @@
}
+/*--- fork and its helper ---*/
+
+static
+void run_fork_handlers ( int what )
+{
+ ForkHandlerEntry entry;
+ int n_h, n_handlers, i, res;
+
+ my_assert(what == 0 || what == 1 || what == 2);
+
+ /* Fetch old counter */
+ VALGRIND_MAGIC_SEQUENCE(n_handlers, -2 /* default */,
+ VG_USERREQ__GET_FHSTACK_USED,
+ 0, 0, 0, 0);
+ my_assert(n_handlers >= 0 && n_handlers < VG_N_FORKHANDLERSTACK);
+
+ /* Prepare handlers (what == 0) are called in opposite order of
+ calls to pthread_atfork. Parent and child handlers are called
+ in the same order as calls to pthread_atfork. */
+ if (what == 0)
+ n_h = n_handlers - 1;
+ else
+ n_h = 0;
+
+ for (i = 0; i < n_handlers; i++) {
+ VALGRIND_MAGIC_SEQUENCE(res, -2 /* default */,
+ VG_USERREQ__GET_FHSTACK_ENTRY,
+ n_h, &entry, 0, 0);
+ my_assert(res == 0);
+ switch (what) {
+ case 0: if (entry.prepare) entry.prepare();
+ n_h--; break;
+ case 1: if (entry.parent) entry.parent();
+ n_h++; break;
+ case 2: if (entry.child) entry.child();
+ n_h++; break;
+ default: barf("run_fork_handlers: invalid what");
+ }
+ }
+
+ if (what != 0 /* prepare */) {
+ /* Empty out the stack. */
+ VALGRIND_MAGIC_SEQUENCE(res, -2 /* default */,
+ VG_USERREQ__SET_FHSTACK_USED,
+ 0, 0, 0, 0);
+ my_assert(res == 0);
+ }
+}
+
+extern
+pid_t __libc_fork(void);
+pid_t __fork(void)
+{
+ pid_t pid;
+ __my_pthread_testcancel();
+ __pthread_mutex_lock(&pthread_atfork_lock);
+
+ run_fork_handlers(0 /* prepare */);
+ pid = __libc_fork();
+ if (pid == 0) {
+ /* I am the child */
+ run_fork_handlers(2 /* child */);
+ __pthread_mutex_init(&pthread_atfork_lock, NULL);
+ } else {
+ /* I am the parent */
+ run_fork_handlers(1 /* parent */);
+ __pthread_mutex_unlock(&pthread_atfork_lock);
+ }
+ return pid;
+}
+
+
+
+
/* ---------------------------------------------------------------------
Nonblocking implementations of select() and poll(). This stuff will
surely rot your mind.