kernel/tools/testing/selftests/efivarfs/open-unlink.c

   1 #include <stdio.h>
   2 #include <stdint.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8
   9 int main(int argc, char **argv)
  10 {
  11         const char *path;
  12         char buf[5];
  13         int fd, rc;
  14
  15         if (argc < 2) {
  16                 fprintf(stderr, "usage: %s <path>\n", argv[0]);
  17                 return EXIT_FAILURE;
  18         }
  19
  20         path = argv[1];
  21
  22         /* attributes: EFI_VARIABLE_NON_VOLATILE |
  23          *              EFI_VARIABLE_BOOTSERVICE_ACCESS |
  24          *              EFI_VARIABLE_RUNTIME_ACCESS
  25          */
  26         *(uint32_t *)buf = 0x7;
  27         buf[4] = 0;
  28
  29         /* create a test variable */
  30         fd = open(path, O_WRONLY | O_CREAT);
  31         if (fd < 0) {
  32                 perror("open(O_WRONLY)");
  33                 return EXIT_FAILURE;
  34         }
  35
  36         rc = write(fd, buf, sizeof(buf));
  37         if (rc != sizeof(buf)) {
  38                 perror("write");
  39                 return EXIT_FAILURE;
  40         }
  41
  42         close(fd);
  43
  44         fd = open(path, O_RDONLY);
  45         if (fd < 0) {
  46                 perror("open");
  47                 return EXIT_FAILURE;
  48         }
  49
  50         if (unlink(path) < 0) {
  51                 perror("unlink");
  52                 return EXIT_FAILURE;
  53         }
  54
  55         rc = read(fd, buf, sizeof(buf));
  56         if (rc > 0) {
  57                 fprintf(stderr, "reading from an unlinked variable "
  58                                 "shouldn't be possible\n");
  59                 return EXIT_FAILURE;
  60         }
  61
  62         return EXIT_SUCCESS;
  63 }