+ int fd;
+ /* Remove anything from prior partial run. */
+ unlink (BASE "file");
+
+ /* Cannot create directory. */
+ errno = 0;
+ ASSERT (open ("nonexist.ent/", O_CREAT | O_RDONLY, 0600) == -1);
+ ASSERT (errno == ENOTDIR || errno == EISDIR || errno == ENOENT);
+
+ /* Create a regular file. */
+ fd = open (BASE "file", O_CREAT | O_RDONLY, 0600);
+ ASSERT (0 <= fd);
+ ASSERT (close (fd) == 0);
+
+ /* Trailing slash handling. */
+ errno = 0;
+ ASSERT (open (BASE "file/", O_RDONLY) == -1);
+ ASSERT (errno == ENOTDIR || errno == EISDIR);
+
+ /* Directories cannot be opened for writing. */
+ errno = 0;
+ ASSERT (open (".", O_WRONLY) == -1);
+ ASSERT (errno == EISDIR);
+
+ /* /dev/null must exist, and be writable. */
+ fd = open ("/dev/null", O_RDONLY);
+ ASSERT (0 <= fd);
+ {
+ char c;
+ ASSERT (read (fd, &c, 1) == 0);
+ }
+ ASSERT (close (fd) == 0);
+ fd = open ("/dev/null", O_WRONLY);
+ ASSERT (0 <= fd);
+ ASSERT (write (fd, "c", 1) == 1);
+ ASSERT (close (fd) == 0);