From 2ac88eecc57ff00e0b5ff803ebcc3465d2d640dd Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri, 22 Apr 2016 09:25:20 -0300
Subject: 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.
---
sysdeps/unix/sysv/linux/nptl-signals.h | 41 ++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
(limited to 'sysdeps/unix/sysv/linux/nptl-signals.h')
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;
--
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