tools/testing/selftests/exec/recursion-depth.c

   1 /*
   2  * Copyright (c) 2019 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 pointing #! script interpreter to self doesn't recurse. */
  17 #include <errno.h>
  18 #include <sched.h>
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23 #include <fcntl.h>
  24 #include <sys/mount.h>
  25 #include <unistd.h>
  26
  27 int main(void)
  28 {
  29         if (unshare(CLONE_NEWNS) == -1) {
  30                 if (errno == ENOSYS || errno == EPERM) {
  31                         fprintf(stderr, "error: unshare, errno %d\n", errno);
  32                         return 4;
  33                 }
  34                 fprintf(stderr, "error: unshare, errno %d\n", errno);
  35                 return 1;
  36         }
  37         if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
  38                 fprintf(stderr, "error: mount '/', errno %d\n", errno);
  39                 return 1;
  40         }
  41         /* Require "exec" filesystem. */
  42         if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1) {
  43                 fprintf(stderr, "error: mount ramfs, errno %d\n", errno);
  44                 return 1;
  45         }
  46
  47 #define FILENAME "/tmp/1"
  48
  49         int fd = creat(FILENAME, 0700);
  50         if (fd == -1) {
  51                 fprintf(stderr, "error: creat, errno %d\n", errno);
  52                 return 1;
  53         }
  54 #define S "#!" FILENAME "\n"
  55         if (write(fd, S, strlen(S)) != strlen(S)) {
  56                 fprintf(stderr, "error: write, errno %d\n", errno);
  57                 return 1;
  58         }
  59         close(fd);
  60
  61         int rv = execve(FILENAME, NULL, NULL);
  62         if (rv == -1 && errno == ELOOP) {
  63                 return 0;
  64         }
  65         fprintf(stderr, "error: execve, rv %d, errno %d\n", rv, errno);
  66         return 1;
  67 }