tests/lstat.c

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#include "test_skel.h"

int main(int argc, char *argv[]) {
  int exit_status = 0;

  // Get two unique paths to play with.
  char foo[] = "tempfile.XXXXXX";
  char bar[] = "tempfile.XXXXXX";
  int fd_foo = mkstemp(foo);
  int fd_bar = mkstemp(bar);
  assert(fd_foo != -1);
  assert(fd_bar != -1);

  // Then delete foo.
  assert(sys_unlink(foo) == 0);

  // Now make foo a symlink to bar.
  assert(symlink(bar, foo) == 0);

  // Make sure sys_stat() and sys_lstat() implementation return different
  // information.

  // We need to check our stat syscalls for EOVERFLOW, as sometimes the integer
  // types used in the stat structures are too small to fit the actual value.
  // E.g. on some systems st_ino is 32-bit, but some filesystems have 64-bit
  // inodes.

  struct kernel_stat lstat_info;
  int rc = sys_lstat(foo, &lstat_info);
  if (rc < 0 && errno == EOVERFLOW) {
    // Bail out since we had an overflow in the stat structure.
    exit_status = SKIP_TEST_EXIT_STATUS;
    goto cleanup;
  }
  assert(rc == 0);

  struct kernel_stat stat_info;
  rc = sys_stat(foo, &stat_info);
  if (rc < 0 && errno == EOVERFLOW) {
    // Bail out since we had an overflow in the stat structure.
    exit_status = SKIP_TEST_EXIT_STATUS;
    goto cleanup;
  }
  assert(rc == 0);

  struct kernel_stat bar_stat_info;
  rc = sys_stat(bar, &bar_stat_info);
  if (rc < 0 && errno == EOVERFLOW) {
    // Bail out since we had an overflow in the stat structure.
    exit_status = SKIP_TEST_EXIT_STATUS;
    goto cleanup;
  }
  assert(rc == 0);

  // lstat should produce information about a symlink.
  assert((lstat_info.st_mode & S_IFMT) == S_IFLNK);

  // stat-ing foo and bar should produce the same inode.
  assert(stat_info.st_ino == bar_stat_info.st_ino);

  // lstat-ing foo should give a different inode than stat-ing foo.
  assert(stat_info.st_ino != lstat_info.st_ino);

cleanup:
  sys_unlink(foo);
  sys_unlink(bar);
  return exit_status;
}