xserver-multidpi/glx/glthread.c
Rami Ylimaki 5b9a52be7e os: Prevent core dump from being truncated.
The problem fixed by this patch can be reproduced on Linux with the
following steps.
- Access NULL pointer intentionally in ProcessOtherEvent on key press.
- Instead of saving core dump to a file, write it into a pipe.
  echo "|/usr/sbin/my-core-dumper" > /proc/sys/kernel/core_pattern
- Dump the core by pressing a key.

While the core is being dumped into the pipe, the smart schedule timer
will cause a pending SIGALRM. Linux kernel stops writing data to the
pipe when there are pending signals. This causes the core dump to be
truncated. On my system I'm expecting a 6 MB dump but the size will be
60 kB instead. The problem is solved if we block the SIGALRM caused by
expired smart schedule timer.

I haven't been able to reproduce this problem in the following cases.
- Save core dump to a file instead of a pipe.
- kill -SEGV `pidof Xorg`
- Press a key to dump core while gdb is attached to Xorg.
- Give option -dumbSched to Xorg.

Also note that the fix works only when NoTrapSignals has the default
value FALSE. The problem can still be reproduced if error signals
aren't trapped. In addition to pending SIGALRM, there is a similar
problem with pending SIGIO from the keyboard driver during core dump.

Signed-off-by: Rami Ylimaki <ext-rami.ylimaki@nokia.com>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2010-02-17 23:20:52 -08:00

381 lines
7.4 KiB
C

/*
* Mesa 3-D graphics library
* Version: 6.5.1
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* XXX There's probably some work to do in order to make this file
* truly reusable outside of Mesa.
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#include <X11/Xfuncproto.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include "glthread.h"
/*
* This file should still compile even when THREADS is not defined.
* This is to make things easier to deal with on the makefile scene..
*/
#ifdef THREADS
#include <errno.h>
/*
* Error messages
*/
#define INIT_TSD_ERROR "_glthread_: failed to allocate key for thread specific data"
#define GET_TSD_ERROR "_glthread_: failed to get thread specific data"
#define SET_TSD_ERROR "_glthread_: thread failed to set thread specific data"
/*
* Magic number to determine if a TSD object has been initialized.
* Kind of a hack but there doesn't appear to be a better cross-platform
* solution.
*/
#define INIT_MAGIC 0xff8adc98
/*
* POSIX Threads -- The best way to go if your platform supports them.
* Solaris >= 2.5 have POSIX threads, IRIX >= 6.4 reportedly
* has them, and many of the free Unixes now have them.
* Be sure to use appropriate -mt or -D_REENTRANT type
* compile flags when building.
*/
#ifdef PTHREADS
_X_EXPORT unsigned long
_glthread_GetID(void)
{
return (unsigned long) pthread_self();
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
if (pthread_key_create(&tsd->key, NULL/*free*/) != 0) {
perror(INIT_TSD_ERROR);
exit(-1);
}
tsd->initMagic = INIT_MAGIC;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
if (tsd->initMagic != (int) INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
return pthread_getspecific(tsd->key);
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
if (tsd->initMagic != (int) INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
if (pthread_setspecific(tsd->key, ptr) != 0) {
perror(SET_TSD_ERROR);
exit(-1);
}
}
#endif /* PTHREADS */
/*
* Solaris/Unix International Threads -- Use only if POSIX threads
* aren't available on your Unix platform. Solaris 2.[34] are examples
* of platforms where this is the case. Be sure to use -mt and/or
* -D_REENTRANT when compiling.
*/
#ifdef SOLARIS_THREADS
#define USE_LOCK_FOR_KEY /* undef this to try a version without
lock for the global key... */
_X_EXPORT unsigned long
_glthread_GetID(void)
{
OsAbort(); /* XXX not implemented yet */
return (unsigned long) 0;
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
if ((errno = mutex_init(&tsd->keylock, 0, NULL)) != 0 ||
(errno = thr_keycreate(&(tsd->key), free)) != 0) {
perror(INIT_TSD_ERROR);
exit(-1);
}
tsd->initMagic = INIT_MAGIC;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
void* ret;
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
#ifdef USE_LOCK_FOR_KEY
mutex_lock(&tsd->keylock);
thr_getspecific(tsd->key, &ret);
mutex_unlock(&tsd->keylock);
#else
if ((errno = thr_getspecific(tsd->key, &ret)) != 0) {
perror(GET_TSD_ERROR);
exit(-1);
}
#endif
return ret;
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
if ((errno = thr_setspecific(tsd->key, ptr)) != 0) {
perror(SET_TSD_ERROR);
exit(-1);
}
}
#undef USE_LOCK_FOR_KEY
#endif /* SOLARIS_THREADS */
/*
* Win32 Threads. The only available option for Windows 95/NT.
* Be sure that you compile using the Multithreaded runtime, otherwise
* bad things will happen.
*/
#ifdef WIN32_THREADS
void FreeTSD(_glthread_TSD *p)
{
if (p->initMagic==INIT_MAGIC) {
TlsFree(p->key);
p->initMagic=0;
}
}
void InsteadOf_exit(int nCode)
{
DWORD dwErr=GetLastError();
}
unsigned long
_glthread_GetID(void)
{
return GetCurrentThreadId();
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
tsd->key = TlsAlloc();
if (tsd->key == TLS_OUT_OF_INDEXES) {
perror("Mesa:_glthread_InitTSD");
InsteadOf_exit(-1);
}
tsd->initMagic = INIT_MAGIC;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
return TlsGetValue(tsd->key);
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
/* the following code assumes that the _glthread_TSD has been initialized
to zero at creation */
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
if (TlsSetValue(tsd->key, ptr) == 0) {
perror("Mesa:_glthread_SetTSD");
InsteadOf_exit(-1);
}
}
#endif /* WIN32_THREADS */
/*
* XFree86 has its own thread wrapper, Xthreads.h
* We wrap it again for GL.
*/
#ifdef USE_XTHREADS
_X_EXPORT unsigned long
_glthread_GetID(void)
{
return (unsigned long) xthread_self();
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
if (xthread_key_create(&tsd->key, NULL) != 0) {
perror(INIT_TSD_ERROR);
exit(-1);
}
tsd->initMagic = INIT_MAGIC;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
void *ptr;
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
xthread_get_specific(tsd->key, &ptr);
return ptr;
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
if (tsd->initMagic != INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
xthread_set_specific(tsd->key, ptr);
}
#endif /* XTHREAD */
/*
* BeOS threads
*/
#ifdef BEOS_THREADS
unsigned long
_glthread_GetID(void)
{
return (unsigned long) find_thread(NULL);
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
tsd->key = tls_allocate();
tsd->initMagic = INIT_MAGIC;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
if (tsd->initMagic != (int) INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
return tls_get(tsd->key);
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
if (tsd->initMagic != (int) INIT_MAGIC) {
_glthread_InitTSD(tsd);
}
tls_set(tsd->key, ptr);
}
#endif /* BEOS_THREADS */
#else /* THREADS */
/*
* no-op functions
*/
_X_EXPORT unsigned long
_glthread_GetID(void)
{
return 0;
}
void
_glthread_InitTSD(_glthread_TSD *tsd)
{
(void) tsd;
}
void *
_glthread_GetTSD(_glthread_TSD *tsd)
{
(void) tsd;
return NULL;
}
void
_glthread_SetTSD(_glthread_TSD *tsd, void *ptr)
{
(void) tsd;
(void) ptr;
}
#endif /* THREADS */