int fd_is_fs_type(int fd, statfs_f_type_t magic_value) {
struct statfs s;
if (fstatfs(fd, &s) < 0)
return -errno;
return is_fs_type(&s, magic_value);
}
bool is_network_fs(const struct statfs *s) {
return is_fs_type(s, CIFS_MAGIC_NUMBER) ||
is_fs_type(s, CODA_SUPER_MAGIC) ||
is_fs_type(s, NCP_SUPER_MAGIC) ||
is_fs_type(s, NFS_SUPER_MAGIC) ||
is_fs_type(s, SMB_SUPER_MAGIC) ||
is_fs_type(s, V9FS_MAGIC) ||
is_fs_type(s, AFS_SUPER_MAGIC) ||
is_fs_type(s, OCFS2_SUPER_MAGIC);
}
int fd_is_network_ns(int fd) {
struct statfs s;
int r;
/* Checks whether the specified file descriptor refers to a network namespace. On old kernels there's no nice
* way to detect that, hence on those we'll return a recognizable error (EUCLEAN), so that callers can handle
* this somewhat nicely.
*
* This function returns > 0 if the fd definitely refers to a network namespace, 0 if it definitely does not
* refer to a network namespace, -EUCLEAN if we can't determine, and other negative error codes on error. */
if (fstatfs(fd, &s) < 0)
return -errno;
if (!is_fs_type(&s, NSFS_MAGIC)) {
/* On really old kernels, there was no "nsfs", and network namespace sockets belonged to procfs
* instead. Handle that in a somewhat smart way. */
if (is_fs_type(&s, PROC_SUPER_MAGIC)) {
struct statfs t;
/* OK, so it is procfs. Let's see if our own network namespace is procfs, too. If so, then the
* passed fd might refer to a network namespace, but we can't know for sure. In that case,
* return a recognizable error. */
if (statfs("/proc/self/ns/net", &t) < 0)
return -errno;
if (s.f_type == t.f_type)
return -EUCLEAN; /* It's possible, we simply don't know */
}
return 0; /* No! */
}
r = ioctl(fd, NS_GET_NSTYPE);
if (r < 0) {
if (errno == ENOTTY) /* Old kernels didn't know this ioctl, let's also return a recognizable error in that case */
return -EUCLEAN;
return -errno;
}
return r == CLONE_NEWNET;
}
bool is_temporary_fs(const struct statfs *s) {
return is_fs_type(s, TMPFS_MAGIC) ||
is_fs_type(s, RAMFS_MAGIC);
}
