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e51d4895 DE |
1 | /* |
2 | * lxc: linux Container library | |
3 | * | |
4 | * Copyright © 2012 Oracle. | |
5 | * | |
6 | * Authors: | |
7 | * Dwight Engen <dwight.engen@oracle.com> | |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
250b1eec | 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
e51d4895 DE |
22 | */ |
23 | ||
24 | #define _GNU_SOURCE | |
25 | #include <stdio.h> | |
26 | #include <signal.h> | |
27 | #include <errno.h> | |
28 | #include <unistd.h> | |
29 | #include <string.h> | |
30 | #include <stdlib.h> | |
31 | #include <fcntl.h> | |
2afd1dc0 | 32 | #include <sys/epoll.h> |
e51d4895 DE |
33 | #include <sys/types.h> |
34 | #include <sys/stat.h> | |
35 | #include <sys/param.h> | |
36 | #include <sys/socket.h> | |
37 | #include <sys/un.h> | |
38 | #include <netinet/in.h> | |
39 | #include <net/if.h> | |
40 | ||
f2363e38 ÇO |
41 | #include "af_unix.h" |
42 | #include "log.h" | |
43 | #include "mainloop.h" | |
44 | #include "monitor.h" | |
45 | #include "utils.h" | |
e51d4895 DE |
46 | |
47 | #define CLIENTFDS_CHUNK 64 | |
48 | ||
49 | lxc_log_define(lxc_monitord, lxc); | |
50 | ||
e51d4895 DE |
51 | static void lxc_monitord_cleanup(void); |
52 | ||
53 | /* | |
54 | * Defines the structure to store the monitor information | |
55 | * @lxcpath : the path being monitored | |
56 | * @fifofd : the file descriptor for publishers (containers) to write state | |
57 | * @listenfd : the file descriptor for subscribers (lxc-monitors) to connect | |
58 | * @clientfds : accepted client file descriptors | |
59 | * @clientfds_size : number of file descriptors clientfds can hold | |
60 | * @clientfds_cnt : the count of valid fds in clientfds | |
61 | * @descr : the lxc_mainloop state | |
62 | */ | |
63 | struct lxc_monitor { | |
64 | const char *lxcpath; | |
65 | int fifofd; | |
66 | int listenfd; | |
67 | int *clientfds; | |
68 | int clientfds_size; | |
69 | int clientfds_cnt; | |
70 | struct lxc_epoll_descr descr; | |
71 | }; | |
72 | ||
8f47bc3f | 73 | static struct lxc_monitor mon; |
2afd1dc0 | 74 | static int quit; |
8f47bc3f | 75 | |
e51d4895 DE |
76 | static int lxc_monitord_fifo_create(struct lxc_monitor *mon) |
77 | { | |
8bf1e61e | 78 | struct flock lk; |
e51d4895 DE |
79 | char fifo_path[PATH_MAX]; |
80 | int ret; | |
81 | ||
9e60f51d DE |
82 | ret = lxc_monitor_fifo_name(mon->lxcpath, fifo_path, sizeof(fifo_path), 1); |
83 | if (ret < 0) | |
84 | return ret; | |
e51d4895 DE |
85 | |
86 | ret = mknod(fifo_path, S_IFIFO|S_IRUSR|S_IWUSR, 0); | |
8bf1e61e DE |
87 | if (ret < 0 && errno != EEXIST) { |
88 | INFO("failed to mknod monitor fifo %s %s", fifo_path, strerror(errno)); | |
e51d4895 DE |
89 | return -1; |
90 | } | |
91 | ||
92 | mon->fifofd = open(fifo_path, O_RDWR); | |
93 | if (mon->fifofd < 0) { | |
94 | unlink(fifo_path); | |
95 | ERROR("failed to open monitor fifo"); | |
96 | return -1; | |
97 | } | |
8bf1e61e DE |
98 | |
99 | lk.l_type = F_WRLCK; | |
100 | lk.l_whence = SEEK_SET; | |
101 | lk.l_start = 0; | |
102 | lk.l_len = 0; | |
103 | if (fcntl(mon->fifofd, F_SETLK, &lk) != 0) { | |
104 | /* another lxc-monitord is already running, don't start up */ | |
105 | DEBUG("lxc-monitord already running on lxcpath %s", mon->lxcpath); | |
106 | close(mon->fifofd); | |
107 | return -1; | |
108 | } | |
e51d4895 DE |
109 | return 0; |
110 | } | |
111 | ||
112 | static int lxc_monitord_fifo_delete(struct lxc_monitor *mon) | |
113 | { | |
114 | char fifo_path[PATH_MAX]; | |
115 | int ret; | |
116 | ||
9e60f51d DE |
117 | ret = lxc_monitor_fifo_name(mon->lxcpath, fifo_path, sizeof(fifo_path), 0); |
118 | if (ret < 0) | |
119 | return ret; | |
120 | ||
e51d4895 DE |
121 | unlink(fifo_path); |
122 | return 0; | |
123 | } | |
124 | ||
125 | static void lxc_monitord_sockfd_remove(struct lxc_monitor *mon, int fd) { | |
126 | int i; | |
127 | ||
128 | if (lxc_mainloop_del_handler(&mon->descr, fd)) | |
129 | CRIT("fd:%d not found in mainloop", fd); | |
130 | close(fd); | |
131 | ||
132 | for (i = 0; i < mon->clientfds_cnt; i++) { | |
133 | if (mon->clientfds[i] == fd) | |
134 | break; | |
135 | } | |
136 | if (i >= mon->clientfds_cnt) { | |
137 | CRIT("fd:%d not found in clients array", fd); | |
138 | lxc_monitord_cleanup(); | |
139 | exit(EXIT_FAILURE); | |
140 | } | |
141 | ||
142 | memmove(&mon->clientfds[i], &mon->clientfds[i+1], | |
143 | (mon->clientfds_cnt - i - 1) * sizeof(mon->clientfds[0])); | |
144 | mon->clientfds_cnt--; | |
145 | } | |
146 | ||
84c92abd | 147 | static int lxc_monitord_sock_handler(int fd, uint32_t events, void *data, |
e51d4895 DE |
148 | struct lxc_epoll_descr *descr) |
149 | { | |
150 | struct lxc_monitor *mon = data; | |
151 | ||
2afd1dc0 DE |
152 | if (events & EPOLLIN) { |
153 | int rc; | |
154 | char buf[4]; | |
155 | ||
156 | rc = read(fd, buf, sizeof(buf)); | |
157 | if (rc > 0 && !strncmp(buf, "quit", 4)) | |
158 | quit = 1; | |
159 | } | |
160 | ||
161 | if (events & EPOLLHUP) | |
162 | lxc_monitord_sockfd_remove(mon, fd); | |
163 | return quit; | |
e51d4895 DE |
164 | } |
165 | ||
84c92abd | 166 | static int lxc_monitord_sock_accept(int fd, uint32_t events, void *data, |
e51d4895 DE |
167 | struct lxc_epoll_descr *descr) |
168 | { | |
169 | int ret,clientfd; | |
170 | struct lxc_monitor *mon = data; | |
171 | struct ucred cred; | |
172 | socklen_t credsz = sizeof(cred); | |
173 | ||
174 | ret = -1; | |
175 | clientfd = accept(fd, NULL, 0); | |
176 | if (clientfd < 0) { | |
177 | SYSERROR("failed to accept connection"); | |
178 | goto out; | |
179 | } | |
180 | ||
181 | if (fcntl(clientfd, F_SETFD, FD_CLOEXEC)) { | |
182 | SYSERROR("failed to set close-on-exec on incoming connection"); | |
183 | goto err1; | |
184 | } | |
185 | ||
186 | if (getsockopt(clientfd, SOL_SOCKET, SO_PEERCRED, &cred, &credsz)) | |
187 | { | |
188 | ERROR("failed to get credentials on socket"); | |
189 | goto err1; | |
190 | } | |
191 | if (cred.uid && cred.uid != geteuid()) { | |
192 | WARN("monitor denied for uid:%d", cred.uid); | |
193 | ret = -EACCES; | |
194 | goto err1; | |
195 | } | |
196 | ||
197 | if (mon->clientfds_cnt + 1 > mon->clientfds_size) { | |
198 | int *clientfds; | |
199 | DEBUG("realloc space for %d clientfds", | |
200 | mon->clientfds_size + CLIENTFDS_CHUNK); | |
201 | clientfds = realloc(mon->clientfds, | |
202 | (mon->clientfds_size + CLIENTFDS_CHUNK) * | |
203 | sizeof(mon->clientfds[0])); | |
204 | if (clientfds == NULL) { | |
205 | ERROR("failed to realloc memory for clientfds"); | |
206 | goto err1; | |
207 | } | |
208 | mon->clientfds = clientfds; | |
209 | mon->clientfds_size += CLIENTFDS_CHUNK; | |
210 | } | |
211 | ||
212 | ret = lxc_mainloop_add_handler(&mon->descr, clientfd, | |
213 | lxc_monitord_sock_handler, mon); | |
214 | if (ret) { | |
215 | ERROR("failed to add socket handler"); | |
216 | goto err1; | |
217 | } | |
218 | ||
219 | mon->clientfds[mon->clientfds_cnt++] = clientfd; | |
220 | INFO("accepted client fd:%d clients:%d", clientfd, mon->clientfds_cnt); | |
221 | goto out; | |
222 | ||
223 | err1: | |
224 | close(clientfd); | |
225 | out: | |
226 | return ret; | |
227 | } | |
228 | ||
229 | static int lxc_monitord_sock_create(struct lxc_monitor *mon) | |
230 | { | |
231 | struct sockaddr_un addr; | |
232 | int fd; | |
233 | ||
234 | if (lxc_monitor_sock_name(mon->lxcpath, &addr) < 0) | |
235 | return -1; | |
236 | ||
aae93dd3 | 237 | fd = lxc_abstract_unix_open(addr.sun_path, SOCK_STREAM, O_TRUNC); |
e51d4895 DE |
238 | if (fd < 0) { |
239 | ERROR("failed to open unix socket : %s", strerror(errno)); | |
240 | return -1; | |
241 | } | |
242 | ||
243 | mon->listenfd = fd; | |
244 | return 0; | |
245 | } | |
246 | ||
247 | static int lxc_monitord_sock_delete(struct lxc_monitor *mon) | |
248 | { | |
249 | struct sockaddr_un addr; | |
250 | ||
251 | if (lxc_monitor_sock_name(mon->lxcpath, &addr) < 0) | |
252 | return -1; | |
253 | if (addr.sun_path[0]) | |
254 | unlink(addr.sun_path); | |
255 | return 0; | |
256 | } | |
257 | ||
258 | static int lxc_monitord_create(struct lxc_monitor *mon) | |
259 | { | |
260 | int ret; | |
261 | ||
262 | ret = lxc_monitord_fifo_create(mon); | |
263 | if (ret < 0) | |
264 | return ret; | |
265 | ||
266 | ret = lxc_monitord_sock_create(mon); | |
267 | return ret; | |
268 | } | |
269 | ||
270 | static void lxc_monitord_delete(struct lxc_monitor *mon) | |
271 | { | |
272 | int i; | |
273 | ||
274 | lxc_mainloop_del_handler(&mon->descr, mon->listenfd); | |
275 | close(mon->listenfd); | |
276 | lxc_monitord_sock_delete(mon); | |
277 | ||
278 | lxc_mainloop_del_handler(&mon->descr, mon->fifofd); | |
e51d4895 | 279 | lxc_monitord_fifo_delete(mon); |
8bf1e61e | 280 | close(mon->fifofd); |
e51d4895 DE |
281 | |
282 | for (i = 0; i < mon->clientfds_cnt; i++) { | |
283 | lxc_mainloop_del_handler(&mon->descr, mon->clientfds[i]); | |
284 | close(mon->clientfds[i]); | |
285 | } | |
286 | mon->clientfds_cnt = 0; | |
287 | } | |
288 | ||
84c92abd | 289 | static int lxc_monitord_fifo_handler(int fd, uint32_t events, void *data, |
e51d4895 DE |
290 | struct lxc_epoll_descr *descr) |
291 | { | |
292 | int ret,i; | |
293 | struct lxc_msg msglxc; | |
294 | struct lxc_monitor *mon = data; | |
295 | ||
296 | ret = read(fd, &msglxc, sizeof(msglxc)); | |
297 | if (ret != sizeof(msglxc)) { | |
298 | SYSERROR("read fifo failed : %s", strerror(errno)); | |
299 | return 1; | |
300 | } | |
301 | ||
302 | for (i = 0; i < mon->clientfds_cnt; i++) { | |
303 | DEBUG("writing client fd:%d", mon->clientfds[i]); | |
304 | ret = write(mon->clientfds[i], &msglxc, sizeof(msglxc)); | |
305 | if (ret < 0) { | |
306 | ERROR("write failed to client sock:%d %d %s", | |
307 | mon->clientfds[i], errno, strerror(errno)); | |
308 | } | |
309 | } | |
310 | ||
311 | return 0; | |
312 | } | |
313 | ||
314 | static int lxc_monitord_mainloop_add(struct lxc_monitor *mon) | |
315 | { | |
316 | int ret; | |
317 | ||
318 | ret = lxc_mainloop_add_handler(&mon->descr, mon->fifofd, | |
319 | lxc_monitord_fifo_handler, mon); | |
320 | if (ret < 0) { | |
321 | ERROR("failed to add to mainloop monitor handler for fifo"); | |
322 | return -1; | |
323 | } | |
324 | ||
325 | ret = lxc_mainloop_add_handler(&mon->descr, mon->listenfd, | |
326 | lxc_monitord_sock_accept, mon); | |
327 | if (ret < 0) { | |
328 | ERROR("failed to add to mainloop monitor handler for listen socket"); | |
329 | return -1; | |
330 | } | |
331 | ||
332 | return 0; | |
333 | } | |
334 | ||
335 | static void lxc_monitord_cleanup(void) | |
336 | { | |
337 | lxc_monitord_delete(&mon); | |
338 | } | |
339 | ||
340 | static void lxc_monitord_sig_handler(int sig) | |
341 | { | |
342 | INFO("caught signal %d", sig); | |
343 | lxc_monitord_cleanup(); | |
344 | exit(EXIT_SUCCESS); | |
345 | } | |
346 | ||
347 | int main(int argc, char *argv[]) | |
348 | { | |
349 | int ret,pipefd; | |
350 | char *lxcpath = argv[1]; | |
351 | char logpath[PATH_MAX]; | |
352 | sigset_t mask; | |
353 | ||
354 | if (argc != 3) { | |
355 | fprintf(stderr, | |
356 | "Usage: lxc-monitord lxcpath sync-pipe-fd\n\n" | |
357 | "NOTE: lxc-monitord is intended for use by lxc internally\n" | |
358 | " and does not need to be run by hand\n\n"); | |
359 | exit(EXIT_FAILURE); | |
360 | } | |
361 | ||
362 | ret = snprintf(logpath, sizeof(logpath), "%s/lxc-monitord.log", | |
6a7f2dcd | 363 | (strcmp(LXCPATH, lxcpath) ? lxcpath : LOGPATH ) ); |
e51d4895 DE |
364 | if (ret < 0 || ret >= sizeof(logpath)) |
365 | return EXIT_FAILURE; | |
366 | ||
ab1bf971 | 367 | ret = lxc_log_init(NULL, logpath, "NOTICE", "lxc-monitord", 0, lxcpath); |
e51d4895 | 368 | if (ret) |
b336d724 | 369 | INFO("Failed to open log file %s, log will be lost", lxcpath); |
6edbfc86 | 370 | lxc_log_options_no_override(); |
e51d4895 DE |
371 | |
372 | pipefd = atoi(argv[2]); | |
373 | ||
374 | if (sigfillset(&mask) || | |
375 | sigdelset(&mask, SIGILL) || | |
376 | sigdelset(&mask, SIGSEGV) || | |
377 | sigdelset(&mask, SIGBUS) || | |
378 | sigdelset(&mask, SIGTERM) || | |
379 | sigprocmask(SIG_BLOCK, &mask, NULL)) { | |
380 | SYSERROR("failed to set signal mask"); | |
13bc2fd2 | 381 | return 1; |
e51d4895 DE |
382 | } |
383 | ||
384 | signal(SIGILL, lxc_monitord_sig_handler); | |
385 | signal(SIGSEGV, lxc_monitord_sig_handler); | |
386 | signal(SIGBUS, lxc_monitord_sig_handler); | |
387 | signal(SIGTERM, lxc_monitord_sig_handler); | |
388 | ||
389 | ret = EXIT_FAILURE; | |
390 | memset(&mon, 0, sizeof(mon)); | |
391 | mon.lxcpath = lxcpath; | |
392 | if (lxc_mainloop_open(&mon.descr)) { | |
393 | ERROR("failed to create mainloop"); | |
394 | goto out; | |
395 | } | |
396 | ||
397 | if (lxc_monitord_create(&mon)) { | |
398 | goto out; | |
399 | } | |
400 | ||
401 | /* sync with parent, we're ignoring the return from write | |
402 | * because regardless if it works or not, the following | |
403 | * close will sync us with the parent process. the | |
404 | * if-empty-statement construct is to quiet the | |
405 | * warn-unused-result warning. | |
406 | */ | |
8f47bc3f SG |
407 | if (write(pipefd, "S", 1)) |
408 | ; | |
e51d4895 DE |
409 | close(pipefd); |
410 | ||
411 | if (lxc_monitord_mainloop_add(&mon)) { | |
412 | ERROR("failed to add mainloop handlers"); | |
413 | goto out; | |
414 | } | |
415 | ||
8bf1e61e | 416 | NOTICE("pid:%d monitoring lxcpath %s", getpid(), mon.lxcpath); |
e51d4895 DE |
417 | for(;;) { |
418 | ret = lxc_mainloop(&mon.descr, 1000 * 30); | |
419 | if (mon.clientfds_cnt <= 0) | |
420 | { | |
2afd1dc0 | 421 | NOTICE("no remaining clients, exiting"); |
e51d4895 DE |
422 | break; |
423 | } | |
424 | } | |
425 | ||
426 | lxc_mainloop_close(&mon.descr); | |
427 | lxc_monitord_cleanup(); | |
428 | ret = EXIT_SUCCESS; | |
429 | NOTICE("monitor exiting"); | |
430 | out: | |
13bc2fd2 SH |
431 | if (ret == 0) |
432 | return 0; | |
433 | return 1; | |
e51d4895 | 434 | } |