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Date: Mon, 01 Sep 2014 00:47:46 +0200
From: Jens Gustedt <Jens.Gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: [PATCH 8/9] separate pthread_create and pthread_exit in two
different TU
---
src/thread/pthread_create.c | 124 ++---------------------------------------
src/thread/pthread_exit.c | 130 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 135 insertions(+), 119 deletions(-)
create mode 100644 src/thread/pthread_exit.c
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index c1feb62..7bc7b0f 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -10,102 +10,16 @@ void *__mmap(void *, size_t, int, int, int, off_t);
int __munmap(void *, size_t);
int __mprotect(void *, size_t, int);
_Noreturn void __thrd_exit(int);
+void __thread_enable(void);
+_Noreturn void __pthread_exit(void *);
+void *__copy_tls(unsigned char *);
+extern volatile size_t __pthread_tsd_size;
static void dummy_0()
{
}
weak_alias(dummy_0, __acquire_ptc);
weak_alias(dummy_0, __release_ptc);
-weak_alias(dummy_0, __pthread_tsd_run_dtors);
-weak_alias(dummy_0, __do_private_robust_list);
-weak_alias(dummy_0, __do_orphaned_stdio_locks);
-
-_Noreturn void __pthread_exit(void *result)
-{
- pthread_t self = __pthread_self();
- sigset_t set;
-
- self->result = result;
-
- while (self->cancelbuf) {
- void (*f)(void *) = self->cancelbuf->__f;
- void *x = self->cancelbuf->__x;
- self->cancelbuf = self->cancelbuf->__next;
- f(x);
- }
-
- __pthread_tsd_run_dtors();
-
- __lock(self->exitlock);
-
- /* Mark this thread dead before decrementing count */
- __lock(self->killlock);
- self->dead = 1;
-
- /* Block all signals before decrementing the live thread count.
- * This is important to ensure that dynamically allocated TLS
- * is not under-allocated/over-committed, and possibly for other
- * reasons as well. */
- __block_all_sigs(&set);
-
- /* Wait to unlock the kill lock, which governs functions like
- * pthread_kill which target a thread id, until signals have
- * been blocked. This precludes observation of the thread id
- * as a live thread (with application code running in it) after
- * the thread was reported dead by ESRCH being returned. */
- __unlock(self->killlock);
-
- /* It's impossible to determine whether this is "the last thread"
- * until performing the atomic decrement, since multiple threads
- * could exit at the same time. For the last thread, revert the
- * decrement and unblock signals to give the atexit handlers and
- * stdio cleanup code a consistent state. */
- if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
- libc.threads_minus_1 = 0;
- __restore_sigs(&set);
- exit(0);
- }
-
- if (self->locale != &libc.global_locale) {
- a_dec(&libc.uselocale_cnt);
- if (self->locale->ctype_utf8)
- a_dec(&libc.bytelocale_cnt_minus_1);
- }
-
- __do_private_robust_list();
- __do_orphaned_stdio_locks();
-
- if (self->detached && self->map_base) {
- /* Detached threads must avoid the kernel clear_child_tid
- * feature, since the virtual address will have been
- * unmapped and possibly already reused by a new mapping
- * at the time the kernel would perform the write. In
- * the case of threads that started out detached, the
- * initial clone flags are correct, but if the thread was
- * detached later (== 2), we need to clear it here. */
- if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
-
- /* The following call unmaps the thread's stack mapping
- * and then exits without touching the stack. */
- __unmapself(self->map_base, self->map_size);
- }
-
- for (;;) __syscall(SYS_exit, 0);
-}
-
-void __do_cleanup_push(struct __ptcb *cb)
-{
- if (!libc.has_thread_pointer) return;
- struct pthread *self = __pthread_self();
- cb->__next = self->cancelbuf;
- self->cancelbuf = cb;
-}
-
-void __do_cleanup_pop(struct __ptcb *cb)
-{
- if (!libc.has_thread_pointer) return;
- __pthread_self()->cancelbuf = cb->__next;
-}
static int start(void *p)
{
@@ -135,24 +49,6 @@ static int start_c11(void *p)
#define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
-/* pthread_key_create.c overrides this */
-static volatile size_t dummy = 0;
-weak_alias(dummy, __pthread_tsd_size);
-static void *dummy_tsd[1] = { 0 };
-weak_alias(dummy_tsd, __pthread_tsd_main);
-
-static FILE *volatile dummy_file = 0;
-weak_alias(dummy_file, __stdin_used);
-weak_alias(dummy_file, __stdout_used);
-weak_alias(dummy_file, __stderr_used);
-
-static void init_file_lock(FILE *f)
-{
- if (f && f->lock<0) f->lock = 0;
-}
-
-void *__copy_tls(unsigned char *);
-
int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
{
int ret, c11 = (attrp == __ATTRP_C11_THREAD);
@@ -167,16 +63,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
if (!libc.can_do_threads) return ENOSYS;
self = __pthread_self();
- if (!libc.threaded) {
- for (FILE *f=libc.ofl_head; f; f=f->next)
- init_file_lock(f);
- init_file_lock(__stdin_used);
- init_file_lock(__stdout_used);
- init_file_lock(__stderr_used);
- __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
- self->tsd = (void **)__pthread_tsd_main;
- libc.threaded = 1;
- }
+ if (!libc.threaded) __thread_enable();
if (attrp && !c11) attr = *attrp;
__acquire_ptc();
@@ -273,5 +160,4 @@ fail_nomem:
return c11 ? ENOMEM : EAGAIN;
}
-weak_alias(__pthread_exit, pthread_exit);
weak_alias(__pthread_create, pthread_create);
diff --git a/src/thread/pthread_exit.c b/src/thread/pthread_exit.c
new file mode 100644
index 0000000..4f51269
--- /dev/null
+++ b/src/thread/pthread_exit.c
@@ -0,0 +1,130 @@
+#define _GNU_SOURCE
+#include "pthread_impl.h"
+#include "stdio_impl.h"
+#include "libc.h"
+#include <sys/mman.h>
+#include <threads.h>
+
+static void dummy_0()
+{
+}
+weak_alias(dummy_0, __pthread_tsd_run_dtors);
+weak_alias(dummy_0, __do_private_robust_list);
+weak_alias(dummy_0, __do_orphaned_stdio_locks);
+
+_Noreturn void __pthread_exit(void *result)
+{
+ pthread_t self = __pthread_self();
+ sigset_t set;
+
+ self->result = result;
+
+ while (self->cancelbuf) {
+ void (*f)(void *) = self->cancelbuf->__f;
+ void *x = self->cancelbuf->__x;
+ self->cancelbuf = self->cancelbuf->__next;
+ f(x);
+ }
+
+ __pthread_tsd_run_dtors();
+
+ __lock(self->exitlock);
+
+ /* Mark this thread dead before decrementing count */
+ __lock(self->killlock);
+ self->dead = 1;
+
+ /* Block all signals before decrementing the live thread count.
+ * This is important to ensure that dynamically allocated TLS
+ * is not under-allocated/over-committed, and possibly for other
+ * reasons as well. */
+ __block_all_sigs(&set);
+
+ /* Wait to unlock the kill lock, which governs functions like
+ * pthread_kill which target a thread id, until signals have
+ * been blocked. This precludes observation of the thread id
+ * as a live thread (with application code running in it) after
+ * the thread was reported dead by ESRCH being returned. */
+ __unlock(self->killlock);
+
+ /* It's impossible to determine whether this is "the last thread"
+ * until performing the atomic decrement, since multiple threads
+ * could exit at the same time. For the last thread, revert the
+ * decrement and unblock signals to give the atexit handlers and
+ * stdio cleanup code a consistent state. */
+ if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
+ libc.threads_minus_1 = 0;
+ __restore_sigs(&set);
+ exit(0);
+ }
+
+ if (self->locale != &libc.global_locale) {
+ a_dec(&libc.uselocale_cnt);
+ if (self->locale->ctype_utf8)
+ a_dec(&libc.bytelocale_cnt_minus_1);
+ }
+
+ __do_private_robust_list();
+ __do_orphaned_stdio_locks();
+
+ if (self->detached && self->map_base) {
+ /* Detached threads must avoid the kernel clear_child_tid
+ * feature, since the virtual address will have been
+ * unmapped and possibly already reused by a new mapping
+ * at the time the kernel would perform the write. In
+ * the case of threads that started out detached, the
+ * initial clone flags are correct, but if the thread was
+ * detached later (== 2), we need to clear it here. */
+ if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
+
+ /* The following call unmaps the thread's stack mapping
+ * and then exits without touching the stack. */
+ __unmapself(self->map_base, self->map_size);
+ }
+
+ for (;;) __syscall(SYS_exit, 0);
+}
+
+void __do_cleanup_push(struct __ptcb *cb)
+{
+ if (!libc.has_thread_pointer) return;
+ struct pthread *self = __pthread_self();
+ cb->__next = self->cancelbuf;
+ self->cancelbuf = cb;
+}
+
+void __do_cleanup_pop(struct __ptcb *cb)
+{
+ if (!libc.has_thread_pointer) return;
+ __pthread_self()->cancelbuf = cb->__next;
+}
+
+/* pthread_key_create.c overrides this */
+static volatile size_t dummy = 0;
+weak_alias(dummy, __pthread_tsd_size);
+static void *dummy_tsd[1] = { 0 };
+weak_alias(dummy_tsd, __pthread_tsd_main);
+
+static FILE *volatile dummy_file = 0;
+weak_alias(dummy_file, __stdin_used);
+weak_alias(dummy_file, __stdout_used);
+weak_alias(dummy_file, __stderr_used);
+
+static void init_file_lock(FILE *f)
+{
+ if (f && f->lock<0) f->lock = 0;
+}
+
+void __thread_enable(void)
+{
+ for (FILE *f=libc.ofl_head; f; f=f->next)
+ init_file_lock(f);
+ init_file_lock(__stdin_used);
+ init_file_lock(__stdout_used);
+ init_file_lock(__stderr_used);
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
+ __pthread_self()->tsd = (void **)__pthread_tsd_main;
+ libc.threaded = 1;
+}
+
+weak_alias(__pthread_exit, pthread_exit);
--
1.7.10.4
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