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If a task exits concurrently, task_pid_nr_ns may return 0. [akpm@linux-foundation.org: coding style tweaks] [adobriyan@gmail.com: test that /proc/*/task doesn't contain "0"] Link: https://lkml.kernel.org/r/YV88AnVzHxPafQ9o@localhost.localdomain Link: https://lkml.kernel.org/r/8735pn5dx7.fsf@oldenburg.str.redhat.com Signed-off-by: Florian Weimer <fweimer@redhat.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
/*
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* Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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// Test that /proc/*/task never contains "0".
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#include <sys/types.h>
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#include <dirent.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <pthread.h>
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static pid_t pid = -1;
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static void atexit_hook(void)
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{
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if (pid > 0) {
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kill(pid, SIGKILL);
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}
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}
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static void *f(void *_)
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{
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return NULL;
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}
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static void sigalrm(int _)
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{
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exit(0);
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}
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int main(void)
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{
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pid = fork();
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if (pid == 0) {
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/* child */
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while (1) {
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pthread_t pth;
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pthread_create(&pth, NULL, f, NULL);
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pthread_join(pth, NULL);
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}
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} else if (pid > 0) {
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/* parent */
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atexit(atexit_hook);
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char buf[64];
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snprintf(buf, sizeof(buf), "/proc/%u/task", pid);
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signal(SIGALRM, sigalrm);
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alarm(1);
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while (1) {
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DIR *d = opendir(buf);
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struct dirent *de;
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while ((de = readdir(d))) {
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if (strcmp(de->d_name, "0") == 0) {
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exit(1);
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}
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}
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closedir(d);
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}
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return 0;
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} else {
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perror("fork");
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return 1;
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}
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}
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