2 * Unix SMB/CIFS implementation.
3 * Samba internal messaging functions
4 * Copyright (C) 2013 by Volker Lendecke
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include "lib/util/data_blob.h"
22 #include "lib/util/debug.h"
23 #include "lib/unix_msg/unix_msg.h"
24 #include "system/filesys.h"
25 #include "lib/messages_dgm.h"
26 #include "lib/param/param.h"
27 #include "poll_funcs/poll_funcs_tevent.h"
28 #include "unix_msg/unix_msg.h"
32 * This will carry enough for a socket path
34 char buf[sizeof(struct sockaddr_un)];
37 struct messaging_dgm_context {
39 struct poll_funcs *msg_callbacks;
41 struct unix_msg_ctx *dgm_ctx;
45 void (*recv_cb)(const uint8_t *msg,
48 void *recv_cb_private_data;
50 bool *have_dgm_context;
53 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
54 uint8_t *msg, size_t msg_len,
57 static int messaging_dgm_lockfile_name(struct sun_path_buf *buf,
58 const char *cache_dir,
63 ret = snprintf(buf->buf, sizeof(buf->buf), "%s/lck/%u", cache_dir,
65 if (ret >= sizeof(buf->buf)) {
71 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c);
73 static int messaging_dgm_lockfile_create(const char *cache_dir,
74 uid_t dir_owner, pid_t pid,
75 int *plockfile_fd, uint64_t unique)
78 struct sun_path_buf dir;
79 struct sun_path_buf lockfile_name;
86 ret = messaging_dgm_lockfile_name(&lockfile_name, cache_dir, pid);
91 /* shorter than lockfile_name, can't overflow */
92 snprintf(dir.buf, sizeof(dir.buf), "%s/lck", cache_dir);
94 ok = directory_create_or_exist_strict(dir.buf, dir_owner, 0755);
97 DEBUG(1, ("%s: Could not create lock directory: %s\n",
98 __func__, strerror(ret)));
102 /* no O_EXCL, existence check is via the fcntl lock */
104 lockfile_fd = open(lockfile_name.buf, O_NONBLOCK|O_CREAT|O_WRONLY,
106 if (lockfile_fd == -1) {
108 DEBUG(1, ("%s: open failed: %s\n", __func__, strerror(errno)));
112 lck = (struct flock) {
117 ret = fcntl(lockfile_fd, F_SETLK, &lck);
120 DEBUG(1, ("%s: fcntl failed: %s\n", __func__, strerror(ret)));
124 unique_len = snprintf(buf, sizeof(buf), "%ju\n", (uintmax_t)unique);
126 /* shorten a potentially preexisting file */
128 ret = ftruncate(lockfile_fd, unique_len);
131 DEBUG(1, ("%s: ftruncate failed: %s\n", __func__,
136 written = write(lockfile_fd, buf, unique_len);
137 if (written != unique_len) {
139 DEBUG(1, ("%s: write failed: %s\n", __func__, strerror(ret)));
143 *plockfile_fd = lockfile_fd;
147 unlink(lockfile_name.buf);
153 static int messaging_dgm_lockfile_remove(const char *cache_dir, pid_t pid)
155 struct sun_path_buf lockfile_name;
158 ret = messaging_dgm_lockfile_name(&lockfile_name, cache_dir, pid);
163 ret = unlink(lockfile_name.buf);
166 DEBUG(10, ("%s: unlink(%s) failed: %s\n", __func__,
167 lockfile_name.buf, strerror(ret)));
173 int messaging_dgm_init(TALLOC_CTX *mem_ctx,
174 struct tevent_context *ev,
175 struct server_id pid,
176 const char *cache_dir,
178 void (*recv_cb)(const uint8_t *msg,
181 void *recv_cb_private_data,
182 struct messaging_dgm_context **pctx)
184 struct messaging_dgm_context *ctx;
188 struct sockaddr_un socket_address;
191 static bool have_dgm_context = false;
193 if (have_dgm_context) {
197 ctx = talloc_zero(mem_ctx, struct messaging_dgm_context);
202 ctx->recv_cb = recv_cb;
203 ctx->recv_cb_private_data = recv_cb_private_data;
205 ctx->cache_dir = talloc_strdup(ctx, cache_dir);
206 if (ctx->cache_dir == NULL) {
209 socket_dir = talloc_asprintf(ctx, "%s/msg", cache_dir);
210 if (socket_dir == NULL) {
214 socket_address = (struct sockaddr_un) { .sun_family = AF_UNIX };
215 sockname_len = snprintf(socket_address.sun_path,
216 sizeof(socket_address.sun_path),
217 "%s/%u", socket_dir, (unsigned)pid.pid);
218 if (sockname_len >= sizeof(socket_address.sun_path)) {
223 ret = messaging_dgm_lockfile_create(cache_dir, dir_owner, pid.pid,
224 &ctx->lockfile_fd, pid.unique_id);
226 DEBUG(1, ("%s: messaging_dgm_create_lockfile failed: %s\n",
227 __func__, strerror(ret)));
232 ctx->msg_callbacks = poll_funcs_init_tevent(ctx);
233 if (ctx->msg_callbacks == NULL) {
237 ctx->tevent_handle = poll_funcs_tevent_register(
238 ctx, ctx->msg_callbacks, ev);
239 if (ctx->tevent_handle == NULL) {
243 ok = directory_create_or_exist_strict(socket_dir, dir_owner, 0700);
245 DEBUG(1, ("Could not create socket directory\n"));
249 TALLOC_FREE(socket_dir);
251 unlink(socket_address.sun_path);
253 generate_random_buffer((uint8_t *)&cookie, sizeof(cookie));
255 ret = unix_msg_init(&socket_address, ctx->msg_callbacks, 1024, cookie,
256 messaging_dgm_recv, ctx, &ctx->dgm_ctx);
258 DEBUG(1, ("unix_msg_init failed: %s\n", strerror(ret)));
262 talloc_set_destructor(ctx, messaging_dgm_context_destructor);
264 ctx->have_dgm_context = &have_dgm_context;
274 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c)
277 * First delete the socket to avoid races. The lockfile is the
278 * indicator that we're still around.
280 unix_msg_free(c->dgm_ctx);
282 if (getpid() == c->pid) {
283 (void)messaging_dgm_lockfile_remove(c->cache_dir, c->pid);
285 close(c->lockfile_fd);
287 if (c->have_dgm_context != NULL) {
288 *c->have_dgm_context = false;
294 int messaging_dgm_send(struct messaging_dgm_context *ctx, pid_t pid,
295 const struct iovec *iov, int iovlen)
297 struct sockaddr_un dst;
301 dst = (struct sockaddr_un) { .sun_family = AF_UNIX };
303 dst_pathlen = snprintf(dst.sun_path, sizeof(dst.sun_path),
304 "%s/msg/%u", ctx->cache_dir, (unsigned)pid);
305 if (dst_pathlen >= sizeof(dst.sun_path)) {
309 DEBUG(10, ("%s: Sending message to %u\n", __func__, (unsigned)pid));
311 ret = unix_msg_send(ctx->dgm_ctx, &dst, iov, iovlen);
316 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
317 uint8_t *msg, size_t msg_len,
320 struct messaging_dgm_context *dgm_ctx = talloc_get_type_abort(
321 private_data, struct messaging_dgm_context);
323 dgm_ctx->recv_cb(msg, msg_len, dgm_ctx->recv_cb_private_data);
326 int messaging_dgm_cleanup(struct messaging_dgm_context *ctx, pid_t pid)
328 struct sun_path_buf lockfile_name, socket_name;
330 struct flock lck = {};
332 ret = messaging_dgm_lockfile_name(&lockfile_name, ctx->cache_dir, pid);
337 /* same length as lockfile_name, can't overflow */
338 snprintf(socket_name.buf, sizeof(socket_name.buf), "%s/msg/%u",
339 ctx->cache_dir, (unsigned)pid);
341 fd = open(lockfile_name.buf, O_NONBLOCK|O_WRONLY, 0);
345 DEBUG(10, ("%s: open(%s) failed: %s\n", __func__,
346 lockfile_name.buf, strerror(ret)));
351 lck.l_type = F_WRLCK;
352 lck.l_whence = SEEK_SET;
356 ret = fcntl(fd, F_SETLK, &lck);
359 DEBUG(10, ("%s: Could not get lock: %s\n", __func__,
365 (void)unlink(socket_name.buf);
366 (void)unlink(lockfile_name.buf);
371 int messaging_dgm_wipe(struct messaging_dgm_context *ctx)
373 struct sun_path_buf msgdir_name;
376 pid_t our_pid = getpid();
380 * We scan the socket directory and not the lock directory. Otherwise
381 * we would race against messaging_dgm_lockfile_create's open(O_CREAT)
385 ret = snprintf(msgdir_name.buf, sizeof(msgdir_name.buf),
386 "%s/msg", ctx->cache_dir);
387 if (ret >= sizeof(msgdir_name.buf)) {
391 msgdir = opendir(msgdir_name.buf);
392 if (msgdir == NULL) {
397 while ((dp = readdir(msgdir)) != NULL) {
400 pid = strtoul(dp->d_name, NULL, 10);
403 * . and .. and other malformed entries
407 if (pid == our_pid) {
409 * fcntl(F_GETLK) will succeed for ourselves, we hold
410 * that lock ourselves.
415 ret = messaging_dgm_cleanup(ctx, pid);
416 DEBUG(10, ("messaging_dgm_cleanup(%lu) returned %s\n",
417 pid, ret ? strerror(ret) : "ok"));
424 void *messaging_dgm_register_tevent_context(TALLOC_CTX *mem_ctx,
425 struct messaging_dgm_context *ctx,
426 struct tevent_context *ev)
428 return poll_funcs_tevent_register(mem_ctx, ctx->msg_callbacks, ev);