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 "system/network.h"
22 #include "system/filesys.h"
23 #include "system/dir.h"
24 #include "lib/util/debug.h"
25 #include "lib/unix_msg/unix_msg.h"
26 #include "lib/messages_dgm.h"
27 #include "poll_funcs/poll_funcs_tevent.h"
28 #include "lib/util/genrand.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;
42 struct sun_path_buf socket_dir;
43 struct sun_path_buf lockfile_dir;
46 void (*recv_cb)(const uint8_t *msg,
51 void *recv_cb_private_data;
53 bool *have_dgm_context;
56 static struct messaging_dgm_context *global_dgm_context;
58 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
59 uint8_t *msg, size_t msg_len,
60 int *fds, size_t num_fds,
63 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c);
65 static int messaging_dgm_lockfile_create(struct messaging_dgm_context *ctx,
66 pid_t pid, int *plockfile_fd,
71 struct sun_path_buf lockfile_name;
77 ret = snprintf(lockfile_name.buf, sizeof(lockfile_name.buf),
78 "%s/%u", ctx->lockfile_dir.buf, (unsigned)pid);
82 if ((unsigned)ret >= sizeof(lockfile_name.buf)) {
86 /* no O_EXCL, existence check is via the fcntl lock */
88 lockfile_fd = open(lockfile_name.buf, O_NONBLOCK|O_CREAT|O_RDWR,
91 if ((lockfile_fd == -1) &&
92 ((errno == ENXIO) /* Linux */ ||
93 (errno == ENODEV) /* Linux kernel bug */ ||
94 (errno == EOPNOTSUPP) /* FreeBSD */)) {
96 * Huh -- a socket? This might be a stale socket from
97 * an upgrade of Samba. Just unlink and retry, nobody
98 * else is supposed to be here at this time.
100 * Yes, this is racy, but I don't see a way to deal
101 * with this properly.
103 unlink(lockfile_name.buf);
105 lockfile_fd = open(lockfile_name.buf,
106 O_NONBLOCK|O_CREAT|O_WRONLY,
110 if (lockfile_fd == -1) {
112 DEBUG(1, ("%s: open failed: %s\n", __func__, strerror(errno)));
116 lck = (struct flock) {
121 ret = fcntl(lockfile_fd, F_SETLK, &lck);
124 DEBUG(1, ("%s: fcntl failed: %s\n", __func__, strerror(ret)));
129 * Directly using the binary value for
130 * SERVERID_UNIQUE_ID_NOT_TO_VERIFY is a layering
131 * violation. But including all of ndr here just for this
132 * seems to be a bit overkill to me. Also, messages_dgm might
133 * be replaced sooner or later by something streams-based,
134 * where unique_id generation will be handled differently.
138 generate_random_buffer((uint8_t *)&unique, sizeof(unique));
139 } while (unique == UINT64_C(0xFFFFFFFFFFFFFFFF));
141 unique_len = snprintf(buf, sizeof(buf), "%ju\n", (uintmax_t)unique);
143 /* shorten a potentially preexisting file */
145 ret = ftruncate(lockfile_fd, unique_len);
148 DEBUG(1, ("%s: ftruncate failed: %s\n", __func__,
153 written = write(lockfile_fd, buf, unique_len);
154 if (written != unique_len) {
156 DEBUG(1, ("%s: write failed: %s\n", __func__, strerror(ret)));
160 *plockfile_fd = lockfile_fd;
165 unlink(lockfile_name.buf);
171 int messaging_dgm_init(struct tevent_context *ev,
173 const char *socket_dir,
174 const char *lockfile_dir,
175 void (*recv_cb)(const uint8_t *msg,
180 void *recv_cb_private_data)
182 struct messaging_dgm_context *ctx;
184 struct sockaddr_un socket_address;
186 static bool have_dgm_context = false;
188 if (have_dgm_context) {
192 ctx = talloc_zero(NULL, struct messaging_dgm_context);
197 ctx->recv_cb = recv_cb;
198 ctx->recv_cb_private_data = recv_cb_private_data;
200 len = strlcpy(ctx->lockfile_dir.buf, lockfile_dir,
201 sizeof(ctx->lockfile_dir.buf));
202 if (len >= sizeof(ctx->lockfile_dir.buf)) {
207 len = strlcpy(ctx->socket_dir.buf, socket_dir,
208 sizeof(ctx->socket_dir.buf));
209 if (len >= sizeof(ctx->socket_dir.buf)) {
214 socket_address = (struct sockaddr_un) { .sun_family = AF_UNIX };
215 len = snprintf(socket_address.sun_path,
216 sizeof(socket_address.sun_path),
217 "%s/%u", socket_dir, (unsigned)ctx->pid);
218 if (len >= sizeof(socket_address.sun_path)) {
223 ret = messaging_dgm_lockfile_create(ctx, ctx->pid, &ctx->lockfile_fd,
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 unlink(socket_address.sun_path);
245 ret = unix_msg_init(&socket_address, ctx->msg_callbacks, 1024,
246 messaging_dgm_recv, ctx, &ctx->dgm_ctx);
248 DEBUG(1, ("unix_msg_init failed: %s\n", strerror(ret)));
252 talloc_set_destructor(ctx, messaging_dgm_context_destructor);
254 ctx->have_dgm_context = &have_dgm_context;
256 global_dgm_context = ctx;
264 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c)
267 * First delete the socket to avoid races. The lockfile is the
268 * indicator that we're still around.
270 unix_msg_free(c->dgm_ctx);
272 if (getpid() == c->pid) {
273 struct sun_path_buf name;
276 ret = snprintf(name.buf, sizeof(name.buf), "%s/%u",
277 c->lockfile_dir.buf, (unsigned)c->pid);
278 if ((ret < 0) || ((size_t)ret >= sizeof(name.buf))) {
280 * We've checked the length when creating, so this
281 * should never happen
287 close(c->lockfile_fd);
289 if (c->have_dgm_context != NULL) {
290 *c->have_dgm_context = false;
296 void messaging_dgm_destroy(void)
298 TALLOC_FREE(global_dgm_context);
301 int messaging_dgm_send(pid_t pid,
302 const struct iovec *iov, int iovlen,
303 const int *fds, size_t num_fds)
305 struct messaging_dgm_context *ctx = global_dgm_context;
306 struct sockaddr_un dst;
314 dst = (struct sockaddr_un) { .sun_family = AF_UNIX };
316 dst_pathlen = snprintf(dst.sun_path, sizeof(dst.sun_path),
317 "%s/%u", ctx->socket_dir.buf, (unsigned)pid);
318 if (dst_pathlen < 0) {
321 if ((size_t)dst_pathlen >= sizeof(dst.sun_path)) {
325 DEBUG(10, ("%s: Sending message to %u\n", __func__, (unsigned)pid));
327 ret = unix_msg_send(ctx->dgm_ctx, &dst, iov, iovlen, fds, num_fds);
332 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
333 uint8_t *msg, size_t msg_len,
334 int *fds, size_t num_fds,
337 struct messaging_dgm_context *dgm_ctx = talloc_get_type_abort(
338 private_data, struct messaging_dgm_context);
340 dgm_ctx->recv_cb(msg, msg_len, fds, num_fds,
341 dgm_ctx->recv_cb_private_data);
344 static int messaging_dgm_read_unique(int fd, uint64_t *punique)
348 unsigned long long unique;
351 rw_ret = pread(fd, buf, sizeof(buf)-1, 0);
357 unique = strtoull(buf, &endptr, 10);
358 if ((unique == 0) && (errno == EINVAL)) {
361 if ((unique == ULLONG_MAX) && (errno == ERANGE)) {
364 if (endptr[0] != '\n') {
371 int messaging_dgm_get_unique(pid_t pid, uint64_t *unique)
373 struct messaging_dgm_context *ctx = global_dgm_context;
374 struct sun_path_buf lockfile_name;
381 if (pid == getpid()) {
383 * Protect against losing our own lock
385 return messaging_dgm_read_unique(ctx->lockfile_fd, unique);
388 ret = snprintf(lockfile_name.buf, sizeof(lockfile_name.buf),
389 "%s/%u", ctx->lockfile_dir.buf, (int)pid);
393 if ((size_t)ret >= sizeof(lockfile_name.buf)) {
397 fd = open(lockfile_name.buf, O_NONBLOCK|O_RDONLY, 0);
402 ret = messaging_dgm_read_unique(fd, unique);
407 int messaging_dgm_cleanup(pid_t pid)
409 struct messaging_dgm_context *ctx = global_dgm_context;
410 struct sun_path_buf lockfile_name, socket_name;
412 struct flock lck = {};
418 len = snprintf(socket_name.buf, sizeof(socket_name.buf), "%s/%u",
419 ctx->socket_dir.buf, (unsigned)pid);
423 if ((size_t)len >= sizeof(socket_name.buf)) {
427 len = snprintf(lockfile_name.buf, sizeof(lockfile_name.buf), "%s/%u",
428 ctx->lockfile_dir.buf, (unsigned)pid);
432 if ((size_t)len >= sizeof(lockfile_name.buf)) {
436 fd = open(lockfile_name.buf, O_NONBLOCK|O_WRONLY, 0);
440 DEBUG(10, ("%s: open(%s) failed: %s\n", __func__,
441 lockfile_name.buf, strerror(ret)));
446 lck.l_type = F_WRLCK;
447 lck.l_whence = SEEK_SET;
451 ret = fcntl(fd, F_SETLK, &lck);
454 if ((ret != EACCES) && (ret != EAGAIN)) {
455 DEBUG(10, ("%s: Could not get lock: %s\n", __func__,
462 DEBUG(10, ("%s: Cleaning up : %s\n", __func__, strerror(ret)));
464 (void)unlink(socket_name.buf);
465 (void)unlink(lockfile_name.buf);
470 int messaging_dgm_wipe(void)
472 struct messaging_dgm_context *ctx = global_dgm_context;
475 pid_t our_pid = getpid();
483 * We scan the socket directory and not the lock directory. Otherwise
484 * we would race against messaging_dgm_lockfile_create's open(O_CREAT)
488 msgdir = opendir(ctx->socket_dir.buf);
489 if (msgdir == NULL) {
493 while ((dp = readdir(msgdir)) != NULL) {
496 pid = strtoul(dp->d_name, NULL, 10);
499 * . and .. and other malformed entries
503 if ((pid_t)pid == our_pid) {
505 * fcntl(F_GETLK) will succeed for ourselves, we hold
506 * that lock ourselves.
511 ret = messaging_dgm_cleanup(pid);
512 DEBUG(10, ("messaging_dgm_cleanup(%lu) returned %s\n",
513 pid, ret ? strerror(ret) : "ok"));
520 void *messaging_dgm_register_tevent_context(TALLOC_CTX *mem_ctx,
521 struct tevent_context *ev)
523 struct messaging_dgm_context *ctx = global_dgm_context;
528 return poll_funcs_tevent_register(mem_ctx, ctx->msg_callbacks, ev);