Refactor Linux raise implementation (BZ#15368)

This patch changes both the nptl and libc Linux raise implementation
to avoid the issues described in BZ#15368.  The strategy used is
summarized in bug report first comment:

 1. Block all signals (including internal NPTL ones);
 2. Get pid and tid directly from syscall (not relying on cached
    values);
 3. Call tgkill;
 4. Restore old signal mask.

Tested on x86_64 and i686.

	[BZ #15368]
	* sysdeps/unix/sysv/linux/nptl-signals.h
	(__nptl_clear_internal_signals): New function.
	(__libc_signal_block_all): Likewise.
	(__libc_signal_block_app): Likewise.
	(__libc_signal_restore_set): Likewise.
	* sysdeps/unix/sysv/linux/pt-raise.c (raise): Use Linux raise.c
	implementation.
	* sysdeps/unix/sysv/linux/raise.c (raise): Reimplement to not use
	the cached pid/tid value in pthread structure.

1 files changed, 41 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/nptl-signals.h b/sysdeps/unix/sysv/linux/nptl-signals.h
index 01f34c27ec..271015903e 100644
--- a/sysdeps/unix/sysv/linux/nptl-signals.h
+++ b/sysdeps/unix/sysv/linux/nptl-signals.h
@@ -39,5 +39,46 @@ __nptl_is_internal_signal (int sig)
   return (sig == SIGCANCEL) || (sig == SIGTIMER) || (sig == SIGSETXID);
 }
 
+/* Remove internal glibc signal from the mask.  */
+static inline void
+__nptl_clear_internal_signals (sigset_t *set)
+{
+  __sigdelset (set, SIGCANCEL);
+  __sigdelset (set, SIGTIMER);
+  __sigdelset (set, SIGSETXID);
+}
+
+#define SIGALL_SET \
+  ((__sigset_t) { .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 } })
+
+/* Block all signals, including internal glibc ones.  */
+static inline int
+__libc_signal_block_all (sigset_t *set)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
+			   set, _NSIG / 8);
+}
+
+/* Block all application signals (excluding internal glibc ones).  */
+static inline int
+__libc_signal_block_app (sigset_t *set)
+{
+  sigset_t allset = SIGALL_SET;
+  __nptl_clear_internal_signals (&allset);
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
+			   _NSIG / 8);
+}
+
+/* Restore current process signal mask.  */
+static inline int
+__libc_signal_restore_set (const sigset_t *set)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
+			   _NSIG / 8);
+}
+
 /* Used to communicate with signal handler.  */
 extern struct xid_command *__xidcmd attribute_hidden;