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authorEric Andersen <andersen@codepoet.org>2004-05-06 09:16:11 +0000
committerEric Andersen <andersen@codepoet.org>2004-05-06 09:16:11 +0000
commit201ca767d53f035f6cb6b1eaeee7b32a2f2f029c (patch)
treee2c5fcd74ebcfd0613ef81360aa26e2401774d72
parentc5fc2713c16d80be5c766460e22d7d2fc6c8c516 (diff)
Alexandre Oliva writes:
The vfork() wrapper defined in libpthread, that's used to run pthread_atfork()-registered handlers, is not only a very bad idea, it's broken and useless. Here's the rationale: [---------snip----------] Since the implementation as it stands is broken (linking a program that vfork()s and exec()s on the child and wait()s on the parent works unless you happen to link with libpthread), and I can't think of any workable solution, I suggest that we simply remove the vfork() overrider in the non-MMU case. Yes, we might lose some small amount of functionality here, but it's not like people running uClinux expect anything resembling actual fork() to work.
-rw-r--r--libpthread/linuxthreads/ptfork.c37
1 files changed, 16 insertions, 21 deletions
diff --git a/libpthread/linuxthreads/ptfork.c b/libpthread/linuxthreads/ptfork.c
index 364db7e69..eb544f34b 100644
--- a/libpthread/linuxthreads/ptfork.c
+++ b/libpthread/linuxthreads/ptfork.c
@@ -17,6 +17,9 @@
/* The "atfork" stuff */
#include <errno.h>
+
+#ifdef __ARCH_HAS_MMU__
+
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
@@ -74,7 +77,7 @@ static inline void pthread_call_handlers(struct handler_list * list)
{
for (/*nothing*/; list != NULL; list = list->next) (list->handler)();
}
-#ifdef __ARCH_HAS_MMU__
+
extern int __libc_fork(void);
pid_t __fork(void)
@@ -105,27 +108,19 @@ pid_t __vfork(void)
return __fork();
}
weak_alias (__vfork, vfork);
+
#else
-pid_t __vfork(void)
-{
- pid_t pid;
- struct handler_list * prepare, * child, * parent;
- pthread_mutex_lock(&pthread_atfork_lock);
- prepare = pthread_atfork_prepare;
- child = pthread_atfork_child;
- parent = pthread_atfork_parent;
- pthread_mutex_unlock(&pthread_atfork_lock);
- pthread_call_handlers(prepare);
- pid = __libc_vfork();
- if (pid == 0) {
- __pthread_reset_main_thread();
- __fresetlockfiles();
- pthread_call_handlers(child);
- } else {
- pthread_call_handlers(parent);
- }
- return pid;
+/* We can't support pthread_atfork without MMU, since we don't have
+ fork(), and we can't offer the correct semantics for vfork(). */
+int pthread_atfork(void (*prepare)(void),
+ void (*parent)(void),
+ void (*child)(void))
+{
+ /* ENOMEM is probably pushing it a little bit.
+ Take it as `no *virtual* memory' :-) */
+ errno = ENOMEM;
+ return -1;
}
-weak_alias (__vfork, vfork);
+
#endif