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"
26 #include "lib/param/param.h"
27 #include "poll_funcs/poll_funcs_tevent.h"
28 #include "unix_msg/unix_msg.h"
29 #include "librpc/gen_ndr/messaging.h"
31 struct messaging_dgm_context {
32 struct messaging_context *msg_ctx;
33 struct poll_funcs msg_callbacks;
34 struct unix_msg_ctx *dgm_ctx;
39 struct messaging_dgm_hdr {
41 enum messaging_type msg_type;
46 static NTSTATUS messaging_dgm_send(struct messaging_context *msg_ctx,
47 struct server_id pid, int msg_type,
48 const DATA_BLOB *data,
49 struct messaging_backend *backend);
50 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
51 uint8_t *msg, size_t msg_len,
54 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c);
56 static int messaging_dgm_lockfile_create(const char *cache_dir, pid_t pid,
57 int *plockfile_fd, uint64_t unique)
64 struct flock lck = {};
69 dirlen = full_path_tos(cache_dir, "lck", buf, sizeof(buf),
75 ok = directory_create_or_exist_strict(dir, sec_initial_uid(), 0755);
78 DEBUG(1, ("%s: Could not create lock directory: %s\n",
79 __func__, strerror(ret)));
84 lockfile_name = talloc_asprintf(talloc_tos(), "%s/%u", dir,
87 if (lockfile_name == NULL) {
88 DEBUG(1, ("%s: talloc_asprintf failed\n", __func__));
92 /* no O_EXCL, existence check is via the fcntl lock */
94 lockfile_fd = open(lockfile_name, O_NONBLOCK|O_CREAT|O_WRONLY, 0644);
95 if (lockfile_fd == -1) {
97 DEBUG(1, ("%s: open failed: %s\n", __func__, strerror(errno)));
101 lck.l_type = F_WRLCK;
102 lck.l_whence = SEEK_SET;
106 ret = fcntl(lockfile_fd, F_SETLK, &lck);
109 DEBUG(1, ("%s: fcntl failed: %s\n", __func__, strerror(ret)));
113 unique_len = snprintf(buf, sizeof(buf), "%"PRIu64, unique);
115 /* shorten a potentially preexisting file */
117 ret = ftruncate(lockfile_fd, unique_len);
120 DEBUG(1, ("%s: ftruncate failed: %s\n", __func__,
125 written = write(lockfile_fd, buf, unique_len);
126 if (written != unique_len) {
128 DEBUG(1, ("%s: write failed: %s\n", __func__, strerror(ret)));
132 *plockfile_fd = lockfile_fd;
136 unlink(lockfile_name);
140 TALLOC_FREE(lockfile_name);
144 static int messaging_dgm_lockfile_remove(const char *cache_dir, pid_t pid)
148 char *lockfile_name, *to_free;
152 fstr_sprintf(fname, "lck/%u", (unsigned)pid);
154 len = full_path_tos(cache_dir, fname, buf, sizeof(buf),
155 &lockfile_name, &to_free);
160 ret = unlink(lockfile_name);
163 DEBUG(10, ("%s: unlink failed: %s\n", __func__,
166 TALLOC_FREE(to_free);
170 NTSTATUS messaging_dgm_init(struct messaging_context *msg_ctx,
172 struct messaging_backend **presult)
174 struct messaging_backend *result;
175 struct messaging_dgm_context *ctx;
176 struct server_id pid = messaging_server_id(msg_ctx);
179 const char *cache_dir;
180 char *socket_dir, *socket_name;
183 cache_dir = lp_cache_directory();
184 if (cache_dir == NULL) {
185 NTSTATUS status = map_nt_error_from_unix(errno);
189 result = talloc(mem_ctx, struct messaging_backend);
190 if (result == NULL) {
193 ctx = talloc_zero(result, struct messaging_dgm_context);
198 result->private_data = ctx;
199 result->send_fn = messaging_dgm_send;
200 ctx->msg_ctx = msg_ctx;
202 ctx->cache_dir = talloc_strdup(ctx, cache_dir);
203 if (ctx->cache_dir == NULL) {
206 socket_dir = talloc_asprintf(ctx, "%s/msg", cache_dir);
207 if (socket_dir == NULL) {
210 socket_name = talloc_asprintf(ctx, "%s/%u", socket_dir,
212 if (socket_name == NULL) {
218 ret = messaging_dgm_lockfile_create(cache_dir, pid.pid,
219 &ctx->lockfile_fd, pid.unique_id);
221 DEBUG(1, ("%s: messaging_dgm_create_lockfile failed: %s\n",
222 __func__, strerror(ret)));
224 return map_nt_error_from_unix(ret);
227 poll_funcs_init_tevent(&ctx->msg_callbacks, msg_ctx->event_ctx);
229 ok = directory_create_or_exist_strict(socket_dir, sec_initial_uid(),
232 DEBUG(1, ("Could not create socket directory\n"));
234 return NT_STATUS_ACCESS_DENIED;
236 TALLOC_FREE(socket_dir);
240 generate_random_buffer((uint8_t *)&cookie, sizeof(cookie));
242 ret = unix_msg_init(socket_name, &ctx->msg_callbacks, 1024, cookie,
243 messaging_dgm_recv, ctx, &ctx->dgm_ctx);
244 TALLOC_FREE(socket_name);
246 DEBUG(1, ("unix_msg_init failed: %s\n", strerror(ret)));
248 return map_nt_error_from_unix(ret);
250 talloc_set_destructor(ctx, messaging_dgm_context_destructor);
257 return NT_STATUS_NO_MEMORY;
260 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c)
262 struct server_id pid = messaging_server_id(c->msg_ctx);
265 * First delete the socket to avoid races. The lockfile is the
266 * indicator that we're still around.
268 unix_msg_free(c->dgm_ctx);
270 if (getpid() == pid.pid) {
271 (void)messaging_dgm_lockfile_remove(c->cache_dir, pid.pid);
273 close(c->lockfile_fd);
277 static NTSTATUS messaging_dgm_send(struct messaging_context *msg_ctx,
278 struct server_id pid, int msg_type,
279 const DATA_BLOB *data,
280 struct messaging_backend *backend)
282 struct messaging_dgm_context *ctx = talloc_get_type_abort(
283 backend->private_data, struct messaging_dgm_context);
286 char *dst_sock, *to_free;
287 struct messaging_dgm_hdr hdr;
292 fstr_sprintf(pid_str, "msg/%u", (unsigned)pid.pid);
294 pathlen = full_path_tos(ctx->cache_dir, pid_str, buf, sizeof(buf),
295 &dst_sock, &to_free);
297 return NT_STATUS_NO_MEMORY;
300 hdr.msg_version = MESSAGE_VERSION;
301 hdr.msg_type = msg_type & MSG_TYPE_MASK;
303 hdr.src = msg_ctx->id;
305 DEBUG(10, ("%s: Sending message 0x%x len %u to %s\n", __func__,
306 (unsigned)hdr.msg_type, (unsigned)data->length,
307 server_id_str(talloc_tos(), &pid)));
309 iov[0].iov_base = &hdr;
310 iov[0].iov_len = sizeof(hdr);
311 iov[1].iov_base = data->data;
312 iov[1].iov_len = data->length;
315 ret = unix_msg_send(ctx->dgm_ctx, dst_sock, iov, ARRAY_SIZE(iov));
318 TALLOC_FREE(to_free);
321 return map_nt_error_from_unix(ret);
326 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
327 uint8_t *msg, size_t msg_len,
330 struct messaging_dgm_context *dgm_ctx = talloc_get_type_abort(
331 private_data, struct messaging_dgm_context);
332 struct messaging_dgm_hdr *hdr;
333 struct messaging_rec rec;
335 if (msg_len < sizeof(*hdr)) {
336 DEBUG(1, ("message too short: %u\n", (unsigned)msg_len));
341 * unix_msg guarantees alignment, so we can cast here
343 hdr = (struct messaging_dgm_hdr *)msg;
345 rec.msg_version = hdr->msg_version;
346 rec.msg_type = hdr->msg_type;
349 rec.buf.data = msg + sizeof(*hdr);
350 rec.buf.length = msg_len - sizeof(*hdr);
352 DEBUG(10, ("%s: Received message 0x%x len %u from %s\n", __func__,
353 (unsigned)hdr->msg_type, (unsigned)rec.buf.length,
354 server_id_str(talloc_tos(), &rec.src)));
356 messaging_dispatch_rec(dgm_ctx->msg_ctx, &rec);
359 NTSTATUS messaging_dgm_cleanup(struct messaging_context *msg_ctx, pid_t pid)
361 struct messaging_dgm_context *ctx = talloc_get_type_abort(
362 msg_ctx->local->private_data, struct messaging_dgm_context);
363 char *lockfile_name, *socket_name;
365 struct flock lck = {};
366 NTSTATUS status = NT_STATUS_OK;
368 lockfile_name = talloc_asprintf(talloc_tos(), "%s/lck/%u",
369 ctx->cache_dir, (unsigned)pid);
370 if (lockfile_name == NULL) {
371 return NT_STATUS_NO_MEMORY;
373 socket_name = talloc_asprintf(lockfile_name, "%s/msg/%u",
374 ctx->cache_dir, (unsigned)pid);
375 if (socket_name == NULL) {
376 TALLOC_FREE(lockfile_name);
377 return NT_STATUS_NO_MEMORY;
380 fd = open(lockfile_name, O_NONBLOCK|O_WRONLY, 0);
382 status = map_nt_error_from_unix(errno);
383 DEBUG(10, ("%s: open(%s) failed: %s\n", __func__,
384 lockfile_name, strerror(errno)));
388 lck.l_type = F_WRLCK;
389 lck.l_whence = SEEK_SET;
393 ret = fcntl(fd, F_SETLK, &lck);
395 status = map_nt_error_from_unix(errno);
396 DEBUG(10, ("%s: Could not get lock: %s\n", __func__,
398 TALLOC_FREE(lockfile_name);
403 (void)unlink(socket_name);
404 (void)unlink(lockfile_name);
407 TALLOC_FREE(lockfile_name);
411 NTSTATUS messaging_dgm_wipe(struct messaging_context *msg_ctx)
413 struct messaging_dgm_context *ctx = talloc_get_type_abort(
414 msg_ctx->local->private_data, struct messaging_dgm_context);
418 pid_t our_pid = getpid();
421 * We scan the socket directory and not the lock directory. Otherwise
422 * we would race against messaging_dgm_lockfile_create's open(O_CREAT)
426 msgdir_name = talloc_asprintf(talloc_tos(), "%s/msg", ctx->cache_dir);
427 if (msgdir_name == NULL) {
428 return NT_STATUS_NO_MEMORY;
431 msgdir = opendir(msgdir_name);
432 TALLOC_FREE(msgdir_name);
433 if (msgdir == NULL) {
434 return map_nt_error_from_unix(errno);
437 while ((dp = readdir(msgdir)) != NULL) {
441 pid = strtoul(dp->d_name, NULL, 10);
444 * . and .. and other malformed entries
448 if (pid == our_pid) {
450 * fcntl(F_GETLK) will succeed for ourselves, we hold
451 * that lock ourselves.
456 status = messaging_dgm_cleanup(msg_ctx, pid);
457 DEBUG(10, ("messaging_dgm_cleanup(%lu) returned %s\n",
458 pid, nt_errstr(status)));