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https://github.com/Zenithsiz/ftmemsim-valgrind.git
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74fb3e1c3e
Most of the time, Valgrind masks async signals, and polls for such signals at regular interval. There is a very narrow range of code (around client syscall logic) where such signals are unmasked (as they must be able to interrupt syscalls). This is the only range of code where Valgrind is expecting to receive such a signal. When gdbserver is ptraced invoked, Valgrind is artificially made to jump out of this code portion. Signals are not masked. When ptraceing valgrind, vgdb will get these signals but cannot transmit them immediately, otherwise they arrive in range of code where they are not expected (causing internal error in syscall logic) and/or causing gdbserver syscalls to be interrupted. 3 solutions to solve that were looked at: 1. have the gdbserver code masking signals "as quickly as possible". Easy to implement, but this leaves still a small window of code where signals are not masked and would cause a problem. 2. have vgdb setting the SIGMASK of valgrind before invoking gdbserver. This would be easy to implement, but changing the SIGMASK of the ptrace-d process is only available on very recent kernels. 3. have vgdb queuing signals, and only transmitting them once gdbserver invocation is finished. This 3rd solution has been implemented. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13896
109 lines
4.4 KiB
C
109 lines
4.4 KiB
C
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/*--------------------------------------------------------------------*/
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/*--- Declarations common for vgdb and implementations ---*/
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/*--- of vgdb-invoker. vgdb.h ---*/
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/*--------------------------------------------------------------------*/
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/*
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This file is part of Valgrind, a dynamic binary instrumentation
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framework.
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Copyright (C) 2011-2013 Philippe Waroquiers
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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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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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307, USA.
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The GNU General Public License is contained in the file COPYING.
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*/
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#ifndef __VGDB_H
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#define __VGDB_H
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#include "pub_core_basics.h"
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#include "pub_core_vki.h"
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#include "pub_core_gdbserver.h"
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#include <sys/types.h>
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extern int debuglevel;
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extern struct timeval dbgtv;
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/* if level <= debuglevel, print timestamp, then print provided by debug info */
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#define DEBUG(level, ...) (level <= debuglevel ? \
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gettimeofday(&dbgtv, NULL), \
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fprintf(stderr, "%ld.%6.6ld ", \
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(long int)dbgtv.tv_sec, \
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(long int)dbgtv.tv_usec), \
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fprintf(stderr, __VA_ARGS__),fflush(stderr) \
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: 0)
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/* same as DEBUG but does not print time stamp info */
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#define PDEBUG(level, ...) (level <= debuglevel ? \
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fprintf(stderr, __VA_ARGS__),fflush(stderr) \
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: 0)
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/* if errno != 0,
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report the errno and fprintf the ... varargs on stderr. */
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#define ERROR(errno, ...) ((errno == 0 ? 0 : perror("syscall failed")), \
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fprintf(stderr, __VA_ARGS__), \
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fflush(stderr))
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/* same as ERROR, but also exits with status 1 */
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#define XERROR(errno, ...) ((errno == 0 ? 0 : perror("syscall failed")), \
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fprintf(stderr, __VA_ARGS__), \
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fflush(stderr), \
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exit(1))
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/* Calls malloc (size). Exits if memory can't be allocated. */
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extern void *vmalloc(size_t size);
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/* Calls realloc (size). Exits if memory can't be allocated. */
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extern void *vrealloc(void *ptr,size_t size);
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/* Will be set to True when any condition indicating we have to shutdown
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is encountered. */
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extern Bool shutting_down;
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extern VgdbShared32 *shared32;
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extern VgdbShared64 *shared64;
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/*--------------------------------------------------------------------*/
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/*--- Below is vgdb-invoker interface which must be implemented by ---*/
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/*--- all vgdb-invoker implementations. ---*/
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/*--------------------------------------------------------------------*/
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/* Possibly produces additional usage information documenting the
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invoker restrictions. */
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void invoker_restrictions_msg(void);
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/* Restore the registers to the saved value, then detaches from all threads.
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Used as a cleanup handler for thread cancellation. */
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void invoker_cleanup_restore_and_detach(void *v_pid);
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/* Ensures that the gdbserver code is invoked by pid.
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If an error occurs, resets the valgrind process
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to the state it had before being invoked.
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Returns True if invoke successful, False otherwise. */
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Bool invoker_invoke_gdbserver(pid_t pid);
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/* Called when connection with valgrind is lost. In case we
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have lost the connection, it means that Valgrind has closed the
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connection and is busy exiting. We can't and don't have to stop it in
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this case. */
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void invoker_valgrind_dying(void);
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#endif // __VGDB_H
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/*--------------------------------------------------------------------*/
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/*--- end ---*/
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/*--------------------------------------------------------------------*/
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