1 /* 2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * 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 25 int 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