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;
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;
76 ret = snprintf(lockfile_name.buf, sizeof(lockfile_name.buf),
77 "%s/%u", ctx->lockfile_dir.buf, (int)pid);
78 if (ret >= sizeof(lockfile_name.buf)) {
82 /* no O_EXCL, existence check is via the fcntl lock */
84 lockfile_fd = open(lockfile_name.buf, O_NONBLOCK|O_CREAT|O_WRONLY,
86 if (lockfile_fd == -1) {
88 DEBUG(1, ("%s: open failed: %s\n", __func__, strerror(errno)));
92 lck = (struct flock) {
97 ret = fcntl(lockfile_fd, F_SETLK, &lck);
100 DEBUG(1, ("%s: fcntl failed: %s\n", __func__, strerror(ret)));
104 unique_len = snprintf(buf, sizeof(buf), "%ju\n", (uintmax_t)unique);
106 /* shorten a potentially preexisting file */
108 ret = ftruncate(lockfile_fd, unique_len);
111 DEBUG(1, ("%s: ftruncate failed: %s\n", __func__,
116 written = write(lockfile_fd, buf, unique_len);
117 if (written != unique_len) {
119 DEBUG(1, ("%s: write failed: %s\n", __func__, strerror(ret)));
123 *plockfile_fd = lockfile_fd;
127 unlink(lockfile_name.buf);
133 int messaging_dgm_init(struct tevent_context *ev,
135 const char *socket_dir,
136 const char *lockfile_dir,
137 void (*recv_cb)(const uint8_t *msg,
142 void *recv_cb_private_data)
144 struct messaging_dgm_context *ctx;
146 struct sockaddr_un socket_address;
149 static bool have_dgm_context = false;
151 if (have_dgm_context) {
155 ctx = talloc_zero(NULL, struct messaging_dgm_context);
160 ctx->recv_cb = recv_cb;
161 ctx->recv_cb_private_data = recv_cb_private_data;
163 len = strlcpy(ctx->lockfile_dir.buf, lockfile_dir,
164 sizeof(ctx->lockfile_dir.buf));
165 if (len >= sizeof(ctx->lockfile_dir.buf)) {
170 len = strlcpy(ctx->socket_dir.buf, socket_dir,
171 sizeof(ctx->socket_dir.buf));
172 if (len >= sizeof(ctx->socket_dir.buf)) {
177 socket_address = (struct sockaddr_un) { .sun_family = AF_UNIX };
178 len = snprintf(socket_address.sun_path,
179 sizeof(socket_address.sun_path),
180 "%s/%u", socket_dir, (unsigned)ctx->pid);
181 if (len >= sizeof(socket_address.sun_path)) {
186 ret = messaging_dgm_lockfile_create(ctx, ctx->pid, &ctx->lockfile_fd,
189 DEBUG(1, ("%s: messaging_dgm_create_lockfile failed: %s\n",
190 __func__, strerror(ret)));
195 ctx->msg_callbacks = poll_funcs_init_tevent(ctx);
196 if (ctx->msg_callbacks == NULL) {
200 ctx->tevent_handle = poll_funcs_tevent_register(
201 ctx, ctx->msg_callbacks, ev);
202 if (ctx->tevent_handle == NULL) {
206 unlink(socket_address.sun_path);
208 generate_random_buffer((uint8_t *)&cookie, sizeof(cookie));
210 ret = unix_msg_init(&socket_address, ctx->msg_callbacks, 1024, cookie,
211 messaging_dgm_recv, ctx, &ctx->dgm_ctx);
213 DEBUG(1, ("unix_msg_init failed: %s\n", strerror(ret)));
217 talloc_set_destructor(ctx, messaging_dgm_context_destructor);
219 ctx->have_dgm_context = &have_dgm_context;
221 global_dgm_context = ctx;
229 static int messaging_dgm_context_destructor(struct messaging_dgm_context *c)
232 * First delete the socket to avoid races. The lockfile is the
233 * indicator that we're still around.
235 unix_msg_free(c->dgm_ctx);
237 if (getpid() == c->pid) {
238 struct sun_path_buf name;
241 ret = snprintf(name.buf, sizeof(name.buf), "%s/%u",
242 c->lockfile_dir.buf, (unsigned)c->pid);
243 if (ret >= sizeof(name.buf)) {
245 * We've checked the length when creating, so this
246 * should never happen
252 close(c->lockfile_fd);
254 if (c->have_dgm_context != NULL) {
255 *c->have_dgm_context = false;
261 void messaging_dgm_destroy(void)
263 TALLOC_FREE(global_dgm_context);
266 int messaging_dgm_send(pid_t pid,
267 const struct iovec *iov, int iovlen,
268 const int *fds, size_t num_fds)
270 struct messaging_dgm_context *ctx = global_dgm_context;
271 struct sockaddr_un dst;
279 dst = (struct sockaddr_un) { .sun_family = AF_UNIX };
281 dst_pathlen = snprintf(dst.sun_path, sizeof(dst.sun_path),
282 "%s/%u", ctx->socket_dir.buf, (unsigned)pid);
283 if (dst_pathlen >= sizeof(dst.sun_path)) {
287 DEBUG(10, ("%s: Sending message to %u\n", __func__, (unsigned)pid));
289 ret = unix_msg_send(ctx->dgm_ctx, &dst, iov, iovlen, fds, num_fds);
294 static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
295 uint8_t *msg, size_t msg_len,
296 int *fds, size_t num_fds,
299 struct messaging_dgm_context *dgm_ctx = talloc_get_type_abort(
300 private_data, struct messaging_dgm_context);
302 dgm_ctx->recv_cb(msg, msg_len, fds, num_fds,
303 dgm_ctx->recv_cb_private_data);
306 int messaging_dgm_cleanup(pid_t pid)
308 struct messaging_dgm_context *ctx = global_dgm_context;
309 struct sun_path_buf lockfile_name, socket_name;
311 struct flock lck = {};
317 len = snprintf(socket_name.buf, sizeof(socket_name.buf), "%s/%u",
318 ctx->socket_dir.buf, (unsigned)pid);
319 if (len >= sizeof(socket_name.buf)) {
323 len = snprintf(lockfile_name.buf, sizeof(lockfile_name.buf), "%s/%u",
324 ctx->lockfile_dir.buf, (unsigned)pid);
325 if (len >= sizeof(lockfile_name.buf)) {
329 fd = open(lockfile_name.buf, O_NONBLOCK|O_WRONLY, 0);
333 DEBUG(10, ("%s: open(%s) failed: %s\n", __func__,
334 lockfile_name.buf, strerror(ret)));
339 lck.l_type = F_WRLCK;
340 lck.l_whence = SEEK_SET;
344 ret = fcntl(fd, F_SETLK, &lck);
347 if ((ret != EACCES) && (ret != EAGAIN)) {
348 DEBUG(10, ("%s: Could not get lock: %s\n", __func__,
355 DEBUG(10, ("%s: Cleaning up : %s\n", __func__, strerror(ret)));
357 (void)unlink(socket_name.buf);
358 (void)unlink(lockfile_name.buf);
363 int messaging_dgm_wipe(void)
365 struct messaging_dgm_context *ctx = global_dgm_context;
368 pid_t our_pid = getpid();
376 * We scan the socket directory and not the lock directory. Otherwise
377 * we would race against messaging_dgm_lockfile_create's open(O_CREAT)
381 msgdir = opendir(ctx->socket_dir.buf);
382 if (msgdir == NULL) {
386 while ((dp = readdir(msgdir)) != NULL) {
389 pid = strtoul(dp->d_name, NULL, 10);
392 * . and .. and other malformed entries
396 if (pid == our_pid) {
398 * fcntl(F_GETLK) will succeed for ourselves, we hold
399 * that lock ourselves.
404 ret = messaging_dgm_cleanup(pid);
405 DEBUG(10, ("messaging_dgm_cleanup(%lu) returned %s\n",
406 pid, ret ? strerror(ret) : "ok"));
413 void *messaging_dgm_register_tevent_context(TALLOC_CTX *mem_ctx,
414 struct tevent_context *ev)
416 struct messaging_dgm_context *ctx = global_dgm_context;
421 return poll_funcs_tevent_register(mem_ctx, ctx->msg_callbacks, ev);