-/* Attempts to shorten 'name' by opening a file descriptor for the directory
- * part of the name and indirecting through /proc/self/fd/<dirfd>/<basename>.
- * On systems with Linux-like /proc, this works as long as <basename> isn't too
- * long.
- *
- * On success, returns 0 and stores the short name in 'short_name' and a
- * directory file descriptor to eventually be closed in '*dirfpd'. */
-static int
-shorten_name_via_proc(const char *name, char short_name[MAX_UN_LEN + 1],
- int *dirfdp)
-{
- char *dir, *base;
- int dirfd;
- int len;
-
- if (!LINUX_DATAPATH) {
- return ENAMETOOLONG;
- }
-
- dir = dir_name(name);
- dirfd = open(dir, O_DIRECTORY | O_RDONLY);
- if (dirfd < 0) {
- static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
- int error = errno;
-
- VLOG_WARN_RL(&rl, "%s: open failed (%s)", dir, ovs_strerror(error));
- free(dir);
-
- return error;
- }
- free(dir);
-
- base = base_name(name);
- len = snprintf(short_name, MAX_UN_LEN + 1,
- "/proc/self/fd/%d/%s", dirfd, base);
- free(base);
-
- if (len >= 0 && len <= MAX_UN_LEN) {
- *dirfdp = dirfd;
- return 0;
- } else {
- close(dirfd);
- return ENAMETOOLONG;
- }
-}
-
-/* Attempts to shorten 'name' by creating a symlink for the directory part of
- * the name and indirecting through <symlink>/<basename>. This works on
- * systems that support symlinks, as long as <basename> isn't too long.
- *
- * On success, returns 0 and stores the short name in 'short_name' and the
- * symbolic link to eventually delete in 'linkname'. */
-static int
-shorten_name_via_symlink(const char *name, char short_name[MAX_UN_LEN + 1],
- char linkname[MAX_UN_LEN + 1])
-{
- char *abs, *dir, *base;
- const char *tmpdir;
- int error;
- int i;
-
- abs = abs_file_name(NULL, name);
- dir = dir_name(abs);
- base = base_name(abs);
- free(abs);
-
- tmpdir = getenv("TMPDIR");
- if (tmpdir == NULL) {
- tmpdir = "/tmp";
- }
-
- for (i = 0; i < 1000; i++) {
- int len;
-
- len = snprintf(linkname, MAX_UN_LEN + 1,
- "%s/ovs-un-c-%"PRIu32, tmpdir, random_uint32());
- error = (len < 0 || len > MAX_UN_LEN ? ENAMETOOLONG
- : symlink(dir, linkname) ? errno
- : 0);
- if (error != EEXIST) {
- break;
- }
- }
-
- if (!error) {
- int len;
-
- fatal_signal_add_file_to_unlink(linkname);
-
- len = snprintf(short_name, MAX_UN_LEN + 1, "%s/%s", linkname, base);
- if (len < 0 || len > MAX_UN_LEN) {
- fatal_signal_unlink_file_now(linkname);
- error = ENAMETOOLONG;
- }
- }
-
- if (error) {
- linkname[0] = '\0';
- }
- free(dir);
- free(base);
-
- return error;
-}
-
-/* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
- * '*un_len' the size of the sockaddr_un.
- *
- * Returns 0 on success, otherwise a positive errno value.
- *
- * Uses '*dirfdp' and 'linkname' to store references to data when the caller no
- * longer needs to use 'un'. On success, freeing these references with
- * free_sockaddr_un() is mandatory to avoid a leak; on failure, freeing them is
- * unnecessary but harmless. */
-static int
-make_sockaddr_un(const char *name, struct sockaddr_un *un, socklen_t *un_len,
- int *dirfdp, char linkname[MAX_UN_LEN + 1])
-{
- char short_name[MAX_UN_LEN + 1];
-
- *dirfdp = -1;
- linkname[0] = '\0';
- if (strlen(name) > MAX_UN_LEN) {
- /* 'name' is too long to fit in a sockaddr_un. Try a workaround. */
- int error = shorten_name_via_proc(name, short_name, dirfdp);
- if (error == ENAMETOOLONG) {
- error = shorten_name_via_symlink(name, short_name, linkname);
- }
- if (error) {
- static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
-
- VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum "
- "%"PRIuSIZE" bytes", name, MAX_UN_LEN);
- return error;
- }
-
- name = short_name;
- }
-
- un->sun_family = AF_UNIX;
- ovs_strzcpy(un->sun_path, name, sizeof un->sun_path);
- *un_len = (offsetof(struct sockaddr_un, sun_path)
- + strlen (un->sun_path) + 1);
- return 0;
-}
-
-/* Clean up after make_sockaddr_un(). */
-static void
-free_sockaddr_un(int dirfd, const char *linkname)
-{
- if (dirfd >= 0) {
- close(dirfd);
- }
- if (linkname[0]) {
- fatal_signal_unlink_file_now(linkname);
- }
-}
-
-/* Binds Unix domain socket 'fd' to a file with permissions 0700. */
-static int
-bind_unix_socket(int fd, struct sockaddr *sun, socklen_t sun_len)
-{
- /* According to _Unix Network Programming_, umask should affect bind(). */
- mode_t old_umask = umask(0077);
- int error = bind(fd, sun, sun_len) ? errno : 0;
- umask(old_umask);
- return error;
-}
-
-/* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
- * SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
- * connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock'
- * is true, the socket is made non-blocking.
- *
- * Returns the socket's fd if successful, otherwise a negative errno value. */
-int
-make_unix_socket(int style, bool nonblock,
- const char *bind_path, const char *connect_path)
-{
- int error;
- int fd;
-
- fd = socket(PF_UNIX, style, 0);
- if (fd < 0) {
- return -errno;
- }
-
- /* Set nonblocking mode right away, if we want it. This prevents blocking
- * in connect(), if connect_path != NULL. (In turn, that's a corner case:
- * it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
- * if a backlog of un-accepted connections has built up in the kernel.) */
- if (nonblock) {
- error = set_nonblocking(fd);
- if (error) {
- goto error;
- }
- }
-
- if (bind_path) {
- char linkname[MAX_UN_LEN + 1];
- struct sockaddr_un un;
- socklen_t un_len;
- int dirfd;
-
- if (unlink(bind_path) && errno != ENOENT) {
- VLOG_WARN("unlinking \"%s\": %s\n",
- bind_path, ovs_strerror(errno));
- }
- fatal_signal_add_file_to_unlink(bind_path);
-
- error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd, linkname);
- if (!error) {
- error = bind_unix_socket(fd, (struct sockaddr *) &un, un_len);
- }
- free_sockaddr_un(dirfd, linkname);
-
- if (error) {
- goto error;
- }
- }
-
- if (connect_path) {
- char linkname[MAX_UN_LEN + 1];
- struct sockaddr_un un;
- socklen_t un_len;
- int dirfd;
-
- error = make_sockaddr_un(connect_path, &un, &un_len, &dirfd, linkname);
- if (!error
- && connect(fd, (struct sockaddr*) &un, un_len)
- && errno != EINPROGRESS) {
- error = errno;
- }
- free_sockaddr_un(dirfd, linkname);
-
- if (error) {
- goto error;
- }
- }
-
- return fd;
-
-error:
- if (error == EAGAIN) {
- error = EPROTO;
- }
- if (bind_path) {
- fatal_signal_unlink_file_now(bind_path);
- }
- close(fd);
- return -error;
-}
-
-int
-get_unix_name_len(socklen_t sun_len)
-{
- return (sun_len >= offsetof(struct sockaddr_un, sun_path)
- ? sun_len - offsetof(struct sockaddr_un, sun_path)
- : 0);
-}
-