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	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.
		
	
		
			
				
	
	
		
			85 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* Special use of signals in NPTL internals.  Linux version.
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|    Copyright (C) 2014-2016 Free Software Foundation, Inc.
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|    This file is part of the GNU C Library.
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| 
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|    The GNU C Library is free software; you can redistribute it and/or
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|    modify it under the terms of the GNU Lesser General Public
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|    License as published by the Free Software Foundation; either
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|    version 2.1 of the License, or (at your option) any later version.
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| 
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|    The GNU C Library is distributed in the hope that it will be useful,
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|    but WITHOUT ANY WARRANTY; without even the implied warranty of
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|    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|    Lesser General Public License for more details.
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| 
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|    You should have received a copy of the GNU Lesser General Public
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|    License along with the GNU C Library; if not, see
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|    <http://www.gnu.org/licenses/>.  */
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| 
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| #include <signal.h>
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| 
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| /* The signal used for asynchronous cancelation.  */
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| #define SIGCANCEL       __SIGRTMIN
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| 
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| 
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| /* Signal needed for the kernel-supported POSIX timer implementation.
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|    We can reuse the cancellation signal since we can distinguish
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|    cancellation from timer expirations.  */
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| #define SIGTIMER        SIGCANCEL
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| 
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| 
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| /* Signal used to implement the setuid et.al. functions.  */
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| #define SIGSETXID       (__SIGRTMIN + 1)
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| 
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| 
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| /* Return is sig is used internally.  */
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| static inline int
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| __nptl_is_internal_signal (int sig)
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| {
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|   return (sig == SIGCANCEL) || (sig == SIGTIMER) || (sig == SIGSETXID);
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| }
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| 
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| /* Remove internal glibc signal from the mask.  */
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| static inline void
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| __nptl_clear_internal_signals (sigset_t *set)
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| {
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|   __sigdelset (set, SIGCANCEL);
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|   __sigdelset (set, SIGTIMER);
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|   __sigdelset (set, SIGSETXID);
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| }
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| 
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| #define SIGALL_SET \
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|   ((__sigset_t) { .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 } })
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| 
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| /* Block all signals, including internal glibc ones.  */
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| static inline int
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| __libc_signal_block_all (sigset_t *set)
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| {
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|   INTERNAL_SYSCALL_DECL (err);
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|   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
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| 			   set, _NSIG / 8);
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| }
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| 
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| /* Block all application signals (excluding internal glibc ones).  */
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| static inline int
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| __libc_signal_block_app (sigset_t *set)
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| {
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|   sigset_t allset = SIGALL_SET;
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|   __nptl_clear_internal_signals (&allset);
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|   INTERNAL_SYSCALL_DECL (err);
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|   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
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| 			   _NSIG / 8);
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| }
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| 
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| /* Restore current process signal mask.  */
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| static inline int
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| __libc_signal_restore_set (const sigset_t *set)
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| {
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|   INTERNAL_SYSCALL_DECL (err);
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|   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
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| 			   _NSIG / 8);
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| }
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| 
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| /* Used to communicate with signal handler.  */
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| extern struct xid_command *__xidcmd attribute_hidden;
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