/* Detect if chown(2) is supported on the target directory. */
static int
is_chown_supported (const char *dir)
{
CLEANUP_FREE char *buf = NULL;
int fd, r, err, saved_errno;
/* Create a randomly named file. */
if (asprintf (&buf, "%s%s/XXXXXXXX.XXX", sysroot, dir) == -1) {
err = errno;
r = cancel_receive ();
errno = err;
reply_with_perror ("asprintf");
return -1;
}
if (random_name (buf) == -1) {
err = errno;
r = cancel_receive ();
errno = err;
reply_with_perror ("random_name");
return -1;
}
/* Maybe 'dir' is not a directory or filesystem not writable? */
fd = open (buf, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0666);
if (fd == -1) {
err = errno;
r = cancel_receive ();
errno = err;
reply_with_perror ("%s", dir);
return -1;
}
/* This is the test. */
r = fchown (fd, 1000, 1000);
saved_errno = errno;
/* Make sure the test file is removed. */
close (fd);
unlink (buf);
if (r == -1 && saved_errno == EPERM) {
/* This means chown is not supported by the filesystem. */
return 0;
}
if (r == -1) {
/* Some other error? */
err = errno;
r = cancel_receive ();
errno = err;
reply_with_perror_errno (saved_errno, "unexpected error in fchown");
return -1;
}
/* Else chown is supported. */
return 1;
}
/* Detect if chown(2) is supported on the target directory. */
static int
is_chown_supported (const char *dir)
{
size_t len = sysroot_len + strlen (dir) + 64;
char buf[len];
int fd, r, saved_errno;
/* Create a randomly named file. */
snprintf (buf, len, "%s%s/XXXXXXXX.XXX", sysroot, dir);
if (random_name (buf) == -1) {
reply_with_perror ("random_name");
return -1;
}
/* Maybe 'dir' is not a directory or filesystem not writable? */
fd = open (buf, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0666);
if (fd == -1) {
reply_with_perror ("%s", dir);
return -1;
}
/* This is the test. */
r = fchown (fd, 1000, 1000);
saved_errno = errno;
/* Make sure the test file is removed. */
close (fd);
unlink (buf);
if (r == -1 && saved_errno == EPERM) {
/* This means chown is not supported by the filesystem. */
return 0;
}
if (r == -1) {
/* Some other error? */
reply_with_perror_errno (saved_errno, "unexpected error in fchown");
return -1;
}
/* Else chown is supported. */
return 1;
}
