+2003-12-20 Ulrich Drepper <drepper@redhat.com>
+
+ * elf/rtld.c (dl_main): Optimize order or subexpressions in if().
+
2003-12-18 Ulrich Drepper <drepper@redhat.com>
* stdio-common/printf_fp.c: Add support to use alternative decimal
* sysdeps/unix/sysv/linux/Makefile (CFLAGS-getpid.c): Define.
* sysdeps/unix/sysv/linux/getpid.c: New file.
+ * pthread_cancel.c: Add comment explaining use of PID field.
+ * sysdeps/unix/sysv/linux/pthread_kill.c: Likewise.
+ * pthread_getattr_np.c: Use abs() when comparing PID and TID fields.
+ * sysdeps/unix/sysv/linux/fork.c: Negate PID field of parent
+ temporarily to signal the field must not be relied on and updated
+ by getpid().
+ * sysdeps/unix/sysv/linux/pt-raise.c: Handle case where PID is
+ temporarily negative.
+ * sysdeps/unix/sysv/linux/raise.c: Likewise.
2003-12-19 Ulrich Drepper <drepper@redhat.com>
thread as canceled. */
INTERNAL_SYSCALL_DECL (err);
+ /* One comment: The PID field in the TCB can temporarily be
+ changed (in fork). But this must not affect this code
+ here. Since this function would have to be called while
+ the thread is executing fork, it would have to happen in
+ a signal handler. But this is no allowed, pthread_cancel
+ is not guaranteed to be async-safe. */
int val;
#if __ASSUME_TGKILL
val = INTERNAL_SYSCALL (tgkill, err, 3,
{
/* No stack information available. This must be for the initial
thread. Get the info in some magical way. */
- assert (thread->pid == thread->tid);
+ assert (abs (thread->pid) == thread->tid);
/* Defined in ld.so. */
extern void *__libc_stack_end;
pid_t ppid = THREAD_GETMEM (THREAD_SELF, tid);
#endif
+ /* We need to prevent the getpid() code to update the PID field so
+ that, if a signal arrives in the child very early and the signal
+ handler uses getpid(), the value returned is correct. */
+ pid_t parentpid = THREAD_GETMEM (THREAD_SELF, pid);
+ THREAD_SETMEM (THREAD_SELF, pid, -parentpid);
+
#ifdef ARCH_FORK
pid = ARCH_FORK ();
#else
*__fork_generation_pointer += 4;
/* Adjust the PID field for the new process. */
- self->pid = self->tid;
+ THREAD_SETMEM (self, pid, THREAD_GETMEM (self, tid));
#if HP_TIMING_AVAIL
/* The CPU clock of the thread and process have to be set to zero. */
{
assert (THREAD_GETMEM (THREAD_SELF, tid) == ppid);
+ /* Restore the PID value. */
+ THREAD_SETMEM (THREAD_SELF, pid, parentpid);
+
/* We execute this even if the 'fork' call failed. */
_IO_list_unlock ();
#include <sysdep.h>
+#ifndef NOT_IN_libc
+static pid_t really_getpid (pid_t oldval);
+#endif
+
+
pid_t
__getpid (void)
{
- pid_t result;
#ifndef NOT_IN_libc
- result = THREAD_GETMEM (THREAD_SELF, pid);
- if (__builtin_expect (result == 0, 0))
+ pid_t result = THREAD_GETMEM (THREAD_SELF, pid);
+ if (__builtin_expect (result <= 0, 0))
+ result = really_getpid (result);
+ return result;
+}
+
+static pid_t
+really_getpid (pid_t oldval)
+{
#endif
- {
- INTERNAL_SYSCALL_DECL (err);
- result = INTERNAL_SYSCALL (getpid, err, 0);
+ INTERNAL_SYSCALL_DECL (err);
+ pid_t result = INTERNAL_SYSCALL (getpid, err, 0);
#ifndef NOT_IN_libc
- THREAD_SETMEM (THREAD_SELF, pid, result);
+ if (oldval == 0)
+ THREAD_SETMEM (THREAD_SELF, pid, result);
#endif
- }
return result;
}
libc_hidden_def (__getpid)
raise (sig)
int sig;
{
+#if __ASSUME_TGKILL || defined __NR_tgkill
+ /* raise is an async-safe function. It could be called while the
+ fork function temporarily invalidated the PID field. Adjust for
+ that. */
+ pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
+ if (__builtin_expect (pid < 0, 0))
+ pid = -pid;
+#endif
+
#if __ASSUME_TGKILL
- return INLINE_SYSCALL (tgkill, 3, THREAD_GETMEM (THREAD_SELF, pid),
- THREAD_GETMEM (THREAD_SELF, tid), sig);
+ return INLINE_SYSCALL (tgkill, 3, pid, THREAD_GETMEM (THREAD_SELF, tid),
+ sig);
#else
# ifdef __NR_tgkill
- int res = INLINE_SYSCALL (tgkill, 3, THREAD_GETMEM (THREAD_SELF, pid),
- THREAD_GETMEM (THREAD_SELF, tid), sig);
+ int res = INLINE_SYSCALL (tgkill, 3, pid, THREAD_GETMEM (THREAD_SELF, tid),
+ sig);
if (res != -1 || errno != ENOSYS)
return res;
# endif
/* We have a special syscall to do the work. */
INTERNAL_SYSCALL_DECL (err);
+ /* One comment: The PID field in the TCB can temporarily be changed
+ (in fork). But this must not affect this code here. Since this
+ function would have to be called while the thread is executing
+ fork, it would have to happen in a signal handler. But this is
+ no allowed, pthread_kill is not guaranteed to be async-safe. */
int val;
#if __ASSUME_TGKILL
val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
int sig;
{
struct pthread *pd = THREAD_SELF;
+#if __ASSUME_TGKILL || defined __NR_tgkill
+ pid_t pid = THREAD_GETMEM (pd, pid);
+#endif
pid_t selftid = THREAD_GETMEM (pd, tid);
if (selftid == 0)
{
#endif
THREAD_SETMEM (pd, tid, selftid);
- /* In this case the TID and PID are the same. */
- THREAD_SETMEM (pd, pid, selftid);
+ /* We do not set the PID field in the TID here since we might be
+ called from a signal handler while the thread executes fork. */
+ pid = selftid;
}
+#if __ASSUME_TGKILL || defined __NR_tgkill
+ else
+ /* raise is an async-safe function. It could be called while the
+ fork function temporarily invalidated the PID field. Adjust for
+ that. */
+ if (__builtin_expect (pid < 0, 0))
+ pid = -pid;
+#endif
#if __ASSUME_TGKILL
- return INLINE_SYSCALL (tgkill, 3, THREAD_GETMEM (pd, pid), selftid, sig);
+ return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
#else
# ifdef __NR_tgkill
- int res = INLINE_SYSCALL (tgkill, 3, THREAD_GETMEM (pd, pid), selftid, sig);
+ int res = INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
if (res != -1 || errno != ENOSYS)
return res;
# endif
git://sourceware.org / glibc.git / commitdiff