/* * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* Test that /proc/loadavg correctly reports last pid in pid namespace. */ #define _GNU_SOURCE #include <errno.h> #include <sched.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <sys/wait.h> int main(void) { pid_t pid; int wstatus; if (unshare(CLONE_NEWPID) == -1) { if (errno == ENOSYS || errno == EPERM) return 2; return 1; } pid = fork(); if (pid == -1) return 1; if (pid == 0) { char buf[128], *p; int fd; ssize_t rv; fd = open("/proc/loadavg" , O_RDONLY); if (fd == -1) return 1; rv = read(fd, buf, sizeof(buf)); if (rv < 3) return 1; p = buf + rv; /* pid 1 */ if (!(p[-3] == ' ' && p[-2] == '1' && p[-1] == '\n')) return 1; pid = fork(); if (pid == -1) return 1; if (pid == 0) return 0; if (waitpid(pid, NULL, 0) == -1) return 1; lseek(fd, 0, SEEK_SET); rv = read(fd, buf, sizeof(buf)); if (rv < 3) return 1; p = buf + rv; /* pid 2 */ if (!(p[-3] == ' ' && p[-2] == '2' && p[-1] == '\n')) return 1; return 0; } if (waitpid(pid, &wstatus, 0) == -1) return 1; if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) return 0; return 1; }