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1/*2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>3 *4 * Permission to use, copy, modify, and distribute this software for any5 * purpose with or without fee is hereby granted, provided that the above6 * copyright notice and this permission notice appear in all copies.7 *8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.15 */16/* Test that /proc/loadavg correctly reports last pid in pid namespace. */17#include <errno.h>18#include <sched.h>19#include <sys/types.h>20#include <sys/stat.h>21#include <fcntl.h>22#include <unistd.h>23#include <sys/wait.h>24 25int main(void)26{27 pid_t pid;28 int wstatus;29 30 if (unshare(CLONE_NEWPID) == -1) {31 if (errno == ENOSYS || errno == EPERM)32 return 4;33 return 1;34 }35 36 pid = fork();37 if (pid == -1)38 return 1;39 if (pid == 0) {40 char buf[128], *p;41 int fd;42 ssize_t rv;43 44 fd = open("/proc/loadavg" , O_RDONLY);45 if (fd == -1)46 return 1;47 rv = read(fd, buf, sizeof(buf));48 if (rv < 3)49 return 1;50 p = buf + rv;51 52 /* pid 1 */53 if (!(p[-3] == ' ' && p[-2] == '1' && p[-1] == '\n'))54 return 1;55 56 pid = fork();57 if (pid == -1)58 return 1;59 if (pid == 0)60 return 0;61 if (waitpid(pid, NULL, 0) == -1)62 return 1;63 64 lseek(fd, 0, SEEK_SET);65 rv = read(fd, buf, sizeof(buf));66 if (rv < 3)67 return 1;68 p = buf + rv;69 70 /* pid 2 */71 if (!(p[-3] == ' ' && p[-2] == '2' && p[-1] == '\n'))72 return 1;73 74 return 0;75 }76 77 if (waitpid(pid, &wstatus, 0) == -1)78 return 1;79 if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0)80 return 0;81 return 1;82}83