mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2025-02-23 13:21:43 +08:00
1d506c26d9
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2022-2024 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU 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, see <http://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <pthread.h>
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#include <unistd.h>
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#include <sys/wait.h>
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static volatile int release_vfork = 0;
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static volatile int release_main = 0;
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static void *
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vforker (void *arg)
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{
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while (!release_vfork)
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usleep (1);
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pid_t pid = vfork ();
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if (pid == 0)
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{
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/* A vfork child is not supposed to mess with the state of the program,
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but it is helpful for the purpose of this test. */
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release_main = 1;
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_exit(7);
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}
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int stat;
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int ret = waitpid (pid, &stat, 0);
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assert (ret == pid);
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assert (WIFEXITED (stat));
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assert (WEXITSTATUS (stat) == 7);
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return NULL;
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}
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static void
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should_break_here (void)
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{}
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int
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main (void)
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{
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pthread_t thread;
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int ret = pthread_create (&thread, NULL, vforker, NULL);
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assert (ret == 0);
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/* We break here first, while the thread is stuck on `!release_fork`. */
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release_vfork = 1;
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/* We set a breakpoint on should_break_here.
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We then set "release_fork" from the debugger and continue. The main
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thread hangs on `!release_main` while the non-main thread vforks. During
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the window of time where the two processes have a shared address space
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(after vfork, before _exit), GDB removes the breakpoints from the address
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space. During that window, only the vfork-ing thread (the non-main
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thread) is frozen by the kernel. The main thread is free to execute. The
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child process sets `release_main`, releasing the main thread. A buggy GDB
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would let the main thread execute during that window, leading to the
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breakpoint on should_break_here being missed. A fixed GDB does not resume
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the threads of the vforking process other than the vforking thread. When
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the vfork child exits, the fixed GDB resumes the main thread, after
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breakpoints are reinserted, so the breakpoint is not missed. */
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while (!release_main)
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usleep (1);
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should_break_here ();
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pthread_join (thread, NULL);
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return 6;
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}
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