#include "bus-socket.h"
#include "fd-util.h"
#include "format-util.h"
+#include "fs-util.h"
#include "hexdecoct.h"
+#include "io-util.h"
#include "macro.h"
#include "missing.h"
+#include "path-util.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "stdio-util.h"
return bus_socket_start_auth_client(b);
}
+static int bus_socket_inotify_setup(sd_bus *b) {
+ _cleanup_free_ int *new_watches = NULL;
+ _cleanup_free_ char *absolute = NULL;
+ size_t n_allocated = 0, n = 0, done = 0, i;
+ unsigned max_follow = 32;
+ const char *p;
+ int wd, r;
+
+ assert(b);
+ assert(b->watch_bind);
+ assert(b->sockaddr.sa.sa_family == AF_UNIX);
+ assert(b->sockaddr.un.sun_path[0] != 0);
+
+ /* Sets up an inotify fd in case watch_bind is enabled: wait until the configured AF_UNIX file system socket
+ * appears before connecting to it. The implemented is pretty simplistic: we just subscribe to relevant changes
+ * to all prefix components of the path, and every time we get an event for that we try to reconnect again,
+ * without actually caring what precisely the event we got told us. If we still can't connect we re-subscribe
+ * to all relevant changes of anything in the path, so that our watches include any possibly newly created path
+ * components. */
+
+ if (b->inotify_fd < 0) {
+ b->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+ if (b->inotify_fd < 0)
+ return -errno;
+ }
+
+ /* Make sure the path is NUL terminated */
+ p = strndupa(b->sockaddr.un.sun_path, sizeof(b->sockaddr.un.sun_path));
+
+ /* Make sure the path is absolute */
+ r = path_make_absolute_cwd(p, &absolute);
+ if (r < 0)
+ goto fail;
+
+ /* Watch all parent directories, and don't mind any prefix that doesn't exist yet. For the innermost directory
+ * that exists we want to know when files are created or moved into it. For all parents of it we just care if
+ * they are removed or renamed. */
+
+ if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ /* Start with the top-level directory, which is a bit simpler than the rest, since it can't be a symlink, and
+ * always exists */
+ wd = inotify_add_watch(b->inotify_fd, "/", IN_CREATE|IN_MOVED_TO);
+ if (wd < 0) {
+ r = log_debug_errno(errno, "Failed to add inotify watch on /: %m");
+ goto fail;
+ } else
+ new_watches[n++] = wd;
+
+ for (;;) {
+ _cleanup_free_ char *component = NULL, *prefix = NULL, *destination = NULL;
+ size_t n_slashes, n_component;
+ char *c = NULL;
+
+ n_slashes = strspn(absolute + done, "/");
+ n_component = n_slashes + strcspn(absolute + done + n_slashes, "/");
+
+ if (n_component == 0) /* The end */
+ break;
+
+ component = strndup(absolute + done, n_component);
+ if (!component) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ /* A trailing slash? That's a directory, and not a socket then */
+ if (path_equal(component, "/")) {
+ r = -EISDIR;
+ goto fail;
+ }
+
+ /* A single dot? Let's eat this up */
+ if (path_equal(component, "/.")) {
+ done += n_component;
+ continue;
+ }
+
+ prefix = strndup(absolute, done + n_component);
+ if (!prefix) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ wd = inotify_add_watch(b->inotify_fd, prefix, IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO|IN_DONT_FOLLOW);
+ log_debug("Added inotify watch for %s on bus %s: %i", prefix, strna(b->description), wd);
+
+ if (wd < 0) {
+ if (IN_SET(errno, ENOENT, ELOOP))
+ break; /* This component doesn't exist yet, or the path contains a cyclic symlink right now */
+
+ r = log_debug_errno(errno, "Failed to add inotify watch on %s: %m", isempty(prefix) ? "/" : prefix);
+ goto fail;
+ } else
+ new_watches[n++] = wd;
+
+ /* Check if this is possibly a symlink. If so, let's follow it and watch it too. */
+ r = readlink_malloc(prefix, &destination);
+ if (r == -EINVAL) { /* not a symlink */
+ done += n_component;
+ continue;
+ }
+ if (r < 0)
+ goto fail;
+
+ if (isempty(destination)) { /* Empty symlink target? Yuck! */
+ r = -EINVAL;
+ goto fail;
+ }
+
+ if (max_follow <= 0) { /* Let's make sure we don't follow symlinks forever */
+ r = -ELOOP;
+ goto fail;
+ }
+
+ if (path_is_absolute(destination)) {
+ /* For absolute symlinks we build the new path and start anew */
+ c = strjoin(destination, absolute + done + n_component);
+ done = 0;
+ } else {
+ _cleanup_free_ char *t = NULL;
+
+ /* For relative symlinks we replace the last component, and try again */
+ t = strndup(absolute, done);
+ if (!t)
+ return -ENOMEM;
+
+ c = strjoin(t, "/", destination, absolute + done + n_component);
+ }
+ if (!c) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ free(absolute);
+ absolute = c;
+
+ max_follow--;
+ }
+
+ /* And now, let's remove all watches from the previous iteration we don't need anymore */
+ for (i = 0; i < b->n_inotify_watches; i++) {
+ bool found = false;
+ size_t j;
+
+ for (j = 0; j < n; j++)
+ if (new_watches[j] == b->inotify_watches[i]) {
+ found = true;
+ break;
+ }
+
+ if (found)
+ continue;
+
+ (void) inotify_rm_watch(b->inotify_fd, b->inotify_watches[i]);
+ }
+
+ free_and_replace(b->inotify_watches, new_watches);
+ b->n_inotify_watches = n;
+
+ return 0;
+
+fail:
+ bus_close_inotify_fd(b);
+ return r;
+}
+
int bus_socket_connect(sd_bus *b) {
+ bool inotify_done = false;
int r;
assert(b);
- assert(b->input_fd < 0);
- assert(b->output_fd < 0);
- assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
- b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
- if (b->input_fd < 0)
- return -errno;
+ for (;;) {
+ assert(b->input_fd < 0);
+ assert(b->output_fd < 0);
+ assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
- b->output_fd = b->input_fd;
+ b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (b->input_fd < 0)
+ return -errno;
- bus_socket_setup(b);
+ b->output_fd = b->input_fd;
+ bus_socket_setup(b);
- r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
- if (r < 0) {
- if (errno == EINPROGRESS)
- return 1;
+ if (connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size) < 0) {
+ if (errno == EINPROGRESS) {
- return -errno;
+ /* If we have any inotify watches open, close them now, we don't need them anymore, as
+ * we have successfully initiated a connection */
+ bus_close_inotify_fd(b);
+
+ /* Note that very likely we are already in BUS_OPENING state here, as we enter it when
+ * we start parsing the address string. The only reason we set the state explicitly
+ * here, is to undo BUS_WATCH_BIND, in case we did the inotify magic. */
+ b->state = BUS_OPENING;
+ return 1;
+ }
+
+ if (IN_SET(errno, ENOENT, ECONNREFUSED) && /* ENOENT → unix socket doesn't exist at all; ECONNREFUSED → unix socket stale */
+ b->watch_bind &&
+ b->sockaddr.sa.sa_family == AF_UNIX &&
+ b->sockaddr.un.sun_path[0] != 0) {
+
+ /* This connection attempt failed, let's release the socket for now, and start with a
+ * fresh one when reconnecting. */
+ bus_close_io_fds(b);
+
+ if (inotify_done) {
+ /* inotify set up already, don't do it again, just return now, and remember
+ * that we are waiting for inotify events now. */
+ b->state = BUS_WATCH_BIND;
+ return 1;
+ }
+
+ /* This is a file system socket, and the inotify logic is enabled. Let's create the necessary inotify fd. */
+ r = bus_socket_inotify_setup(b);
+ if (r < 0)
+ return r;
+
+ /* Let's now try to connect a second time, because in theory there's otherwise a race
+ * here: the socket might have been created in the time between our first connect() and
+ * the time we set up the inotify logic. But let's remember that we set up inotify now,
+ * so that we don't do the connect() more than twice. */
+ inotify_done = true;
+
+ } else
+ return -errno;
+ } else
+ break;
}
+ /* Yay, established, we don't need no inotify anymore! */
+ bus_close_inotify_fd(b);
+
return bus_socket_start_auth(b);
}
return bus_socket_read_auth(b);
}
+
+int bus_socket_process_watch_bind(sd_bus *b) {
+ int r, q;
+
+ assert(b);
+ assert(b->state == BUS_WATCH_BIND);
+ assert(b->inotify_fd >= 0);
+
+ r = flush_fd(b->inotify_fd);
+ if (r <= 0)
+ return r;
+
+ log_debug("Got inotify event on bus %s.", strna(b->description));
+
+ /* We flushed events out of the inotify fd. In that case, maybe the socket is valid now? Let's try to connect
+ * to it again */
+
+ r = bus_socket_connect(b);
+ if (r < 0)
+ return r;
+
+ q = bus_attach_io_events(b);
+ if (q < 0)
+ return q;
+
+ q = bus_attach_inotify_event(b);
+ if (q < 0)
+ return q;
+
+ return r;
+}
projects / thirdparty / systemd.git / blobdiff