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Commit | Line | Data |
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0ad19a3f | 1 | /* |
2 | * lxc: linux Container library | |
3 | * | |
4 | * (C) Copyright IBM Corp. 2007, 2008 | |
5 | * | |
6 | * Authors: | |
9afe19d6 | 7 | * Daniel Lezcano <daniel.lezcano at free.fr> |
e51d4895 | 8 | * Dwight Engen <dwight.engen@oracle.com> |
0ad19a3f | 9 | * |
10 | * This library is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU Lesser General Public | |
12 | * License as published by the Free Software Foundation; either | |
13 | * version 2.1 of the License, or (at your option) any later version. | |
14 | * | |
15 | * This library is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * Lesser General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU Lesser General Public | |
21 | * License along with this library; if not, write to the Free Software | |
250b1eec | 22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
0ad19a3f | 23 | */ |
e51d4895 | 24 | |
0ad19a3f | 25 | #include <errno.h> |
0ad19a3f | 26 | #include <fcntl.h> |
b45c7011 | 27 | #include <inttypes.h> |
292b1d17 CB |
28 | #include <poll.h> |
29 | #include <stddef.h> | |
b45c7011 | 30 | #include <stdint.h> |
292b1d17 CB |
31 | #include <stdio.h> |
32 | #include <stdlib.h> | |
33 | #include <string.h> | |
34 | #include <unistd.h> | |
35 | #include <net/if.h> | |
36 | #include <netinet/in.h> | |
0ad19a3f | 37 | #include <sys/param.h> |
0ad19a3f | 38 | #include <sys/socket.h> |
292b1d17 CB |
39 | #include <sys/stat.h> |
40 | #include <sys/types.h> | |
e51d4895 | 41 | #include <sys/wait.h> |
b113348e | 42 | |
292b1d17 | 43 | #include "config.h" |
31c53c2e | 44 | #include "af_unix.h" |
292b1d17 | 45 | #include "error.h" |
f2363e38 ÇO |
46 | #include "log.h" |
47 | #include "lxclock.h" | |
f2363e38 | 48 | #include "monitor.h" |
292b1d17 | 49 | #include "state.h" |
f2363e38 | 50 | #include "utils.h" |
36eb9bde | 51 | |
9de31d5a CB |
52 | #ifndef HAVE_STRLCPY |
53 | #include "include/strlcpy.h" | |
54 | #endif | |
55 | ||
36eb9bde | 56 | lxc_log_define(lxc_monitor, lxc); |
0ad19a3f | 57 | |
e51d4895 | 58 | /* routines used by monitor publishers (containers) */ |
9e60f51d DE |
59 | int lxc_monitor_fifo_name(const char *lxcpath, char *fifo_path, size_t fifo_path_sz, |
60 | int do_mkdirp) | |
61 | { | |
62 | int ret; | |
44b9ae4b | 63 | char *rundir; |
9e60f51d DE |
64 | |
65 | rundir = get_rundir(); | |
97a696c6 SG |
66 | if (!rundir) |
67 | return -1; | |
68 | ||
9e60f51d DE |
69 | if (do_mkdirp) { |
70 | ret = snprintf(fifo_path, fifo_path_sz, "%s/lxc/%s", rundir, lxcpath); | |
292b1d17 CB |
71 | if (ret < 0 || (size_t)ret >= fifo_path_sz) { |
72 | ERROR("rundir/lxcpath (%s/%s) too long for monitor fifo.", rundir, lxcpath); | |
44b9ae4b | 73 | free(rundir); |
9e60f51d DE |
74 | return -1; |
75 | } | |
9e60f51d | 76 | ret = mkdir_p(fifo_path, 0755); |
9e60f51d | 77 | if (ret < 0) { |
292b1d17 | 78 | ERROR("Unable to create monitor fifo directory %s.", fifo_path); |
44b9ae4b | 79 | free(rundir); |
9e60f51d DE |
80 | return ret; |
81 | } | |
82 | } | |
83 | ret = snprintf(fifo_path, fifo_path_sz, "%s/lxc/%s/monitor-fifo", rundir, lxcpath); | |
292b1d17 CB |
84 | if (ret < 0 || (size_t)ret >= fifo_path_sz) { |
85 | ERROR("rundir/lxcpath (%s/%s) too long for monitor fifo.", rundir, lxcpath); | |
44b9ae4b | 86 | free(rundir); |
9e60f51d DE |
87 | return -1; |
88 | } | |
44b9ae4b | 89 | free(rundir); |
9e60f51d DE |
90 | return 0; |
91 | } | |
92 | ||
e51d4895 | 93 | static void lxc_monitor_fifo_send(struct lxc_msg *msg, const char *lxcpath) |
0ad19a3f | 94 | { |
e51d4895 DE |
95 | int fd,ret; |
96 | char fifo_path[PATH_MAX]; | |
97 | ||
98 | BUILD_BUG_ON(sizeof(*msg) > PIPE_BUF); /* write not guaranteed atomic */ | |
9e60f51d DE |
99 | |
100 | ret = lxc_monitor_fifo_name(lxcpath, fifo_path, sizeof(fifo_path), 0); | |
101 | if (ret < 0) | |
9123e471 | 102 | return; |
80f41298 | 103 | |
292b1d17 CB |
104 | /* Open the fifo nonblock in case the monitor is dead, we don't want the |
105 | * open to wait for a reader since it may never come. | |
8bf1e61e | 106 | */ |
292b1d17 | 107 | fd = open(fifo_path, O_WRONLY | O_NONBLOCK); |
e51d4895 | 108 | if (fd < 0) { |
292b1d17 CB |
109 | /* It is normal for this open() to fail with ENXIO when there is |
110 | * no monitor running, so we don't log it. | |
e51d4895 | 111 | */ |
2469f9b6 | 112 | if (errno == ENXIO || errno == ENOENT) |
292b1d17 CB |
113 | return; |
114 | ||
2469f9b6 | 115 | WARN("%s - Failed to open fifo to send message", strerror(errno)); |
31c53c2e | 116 | return; |
e51d4895 | 117 | } |
0ad19a3f | 118 | |
92ffb6d8 DE |
119 | if (fcntl(fd, F_SETFL, O_WRONLY) < 0) { |
120 | close(fd); | |
8bf1e61e | 121 | return; |
92ffb6d8 | 122 | } |
8bf1e61e | 123 | |
e51d4895 DE |
124 | ret = write(fd, msg, sizeof(*msg)); |
125 | if (ret != sizeof(*msg)) { | |
e8b9ac8f | 126 | close(fd); |
292b1d17 | 127 | SYSERROR("Failed to write to monitor fifo \"%s\".", fifo_path); |
e51d4895 DE |
128 | return; |
129 | } | |
0ad19a3f | 130 | |
131 | close(fd); | |
132 | } | |
133 | ||
292b1d17 CB |
134 | void lxc_monitor_send_state(const char *name, lxc_state_t state, |
135 | const char *lxcpath) | |
eae6543d | 136 | { |
292b1d17 | 137 | struct lxc_msg msg = {.type = lxc_msg_state, .value = state}; |
eae6543d | 138 | |
9de31d5a | 139 | (void)strlcpy(msg.name, name, sizeof(msg.name)); |
e51d4895 | 140 | lxc_monitor_fifo_send(&msg, lxcpath); |
0ad19a3f | 141 | } |
142 | ||
292b1d17 CB |
143 | void lxc_monitor_send_exit_code(const char *name, int exit_code, |
144 | const char *lxcpath) | |
1787abca | 145 | { |
292b1d17 | 146 | struct lxc_msg msg = {.type = lxc_msg_exit_code, .value = exit_code}; |
1787abca | 147 | |
9de31d5a | 148 | (void)strlcpy(msg.name, name, sizeof(msg.name)); |
1787abca JTLB |
149 | lxc_monitor_fifo_send(&msg, lxcpath); |
150 | } | |
151 | ||
e51d4895 DE |
152 | /* routines used by monitor subscribers (lxc-monitor) */ |
153 | int lxc_monitor_close(int fd) | |
0ad19a3f | 154 | { |
dd1d77f9 | 155 | return close(fd); |
e51d4895 DE |
156 | } |
157 | ||
fcaef9c7 CB |
158 | /* Enforces \0-termination for the abstract unix socket. This is not required |
159 | * but allows us to print it out. | |
160 | * | |
161 | * Older version of liblxc only allowed for 105 bytes to be used for the | |
162 | * abstract unix domain socket name because the code for our abstract unix | |
163 | * socket handling performed invalid checks. Since we \0-terminate we could now | |
164 | * have a maximum of 106 chars. But to not break backwards compatibility we keep | |
165 | * the limit at 105. | |
166 | */ | |
e51d4895 DE |
167 | int lxc_monitor_sock_name(const char *lxcpath, struct sockaddr_un *addr) { |
168 | size_t len; | |
169 | int ret; | |
073135ba | 170 | char *path; |
b45c7011 | 171 | uint64_t hash; |
e51d4895 | 172 | |
b45c7011 DE |
173 | /* addr.sun_path is only 108 bytes, so we hash the full name and |
174 | * then append as much of the name as we can fit. | |
9123e471 | 175 | */ |
e51d4895 DE |
176 | memset(addr, 0, sizeof(*addr)); |
177 | addr->sun_family = AF_UNIX; | |
292b1d17 | 178 | |
fcaef9c7 | 179 | /* strlen("lxc/") + strlen("/monitor-sock") + 1 = 18 */ |
073135ba SH |
180 | len = strlen(lxcpath) + 18; |
181 | path = alloca(len); | |
182 | ret = snprintf(path, len, "lxc/%s/monitor-sock", lxcpath); | |
292b1d17 | 183 | if (ret < 0 || (size_t)ret >= len) { |
fcaef9c7 | 184 | ERROR("failed to create name for monitor socket"); |
9e60f51d DE |
185 | return -1; |
186 | } | |
9e60f51d | 187 | |
fcaef9c7 CB |
188 | /* Note: snprintf() will \0-terminate addr->sun_path on the 106th byte |
189 | * and so the abstract socket name has 105 "meaningful" characters. This | |
190 | * is absolutely intentional. For further info read the comment for this | |
191 | * function above! | |
192 | */ | |
073135ba | 193 | len = sizeof(addr->sun_path) - 1; |
b45c7011 | 194 | hash = fnv_64a_buf(path, ret, FNV1A_64_INIT); |
fcaef9c7 CB |
195 | ret = snprintf(addr->sun_path, len, "@lxc/%016" PRIx64 "/%s", hash, lxcpath); |
196 | if (ret < 0) { | |
197 | ERROR("failed to create hashed name for monitor socket"); | |
9123e471 | 198 | return -1; |
fcaef9c7 | 199 | } |
292b1d17 | 200 | |
fcaef9c7 CB |
201 | /* replace @ with \0 */ |
202 | addr->sun_path[0] = '\0'; | |
203 | INFO("using monitor socket name \"%s\" (length of socket name %zu must be <= %zu)", &addr->sun_path[1], strlen(&addr->sun_path[1]), sizeof(addr->sun_path) - 3); | |
292b1d17 | 204 | |
e51d4895 DE |
205 | return 0; |
206 | } | |
0ad19a3f | 207 | |
e51d4895 DE |
208 | int lxc_monitor_open(const char *lxcpath) |
209 | { | |
210 | struct sockaddr_un addr; | |
292b1d17 CB |
211 | int fd; |
212 | size_t retry; | |
aae93dd3 | 213 | size_t len; |
fcaef9c7 | 214 | int backoff_ms[] = {10, 50, 100}; |
e51d4895 DE |
215 | |
216 | if (lxc_monitor_sock_name(lxcpath, &addr) < 0) | |
217 | return -1; | |
218 | ||
fcaef9c7 CB |
219 | len = strlen(&addr.sun_path[1]); |
220 | DEBUG("opening monitor socket %s with len %zu", &addr.sun_path[1], len); | |
aae93dd3 | 221 | if (len >= sizeof(addr.sun_path) - 1) { |
aae93dd3 | 222 | errno = ENAMETOOLONG; |
fcaef9c7 | 223 | ERROR("name of monitor socket too long (%zu bytes): %s", len, strerror(errno)); |
c8dcf778 | 224 | return -1; |
aae93dd3 ÇO |
225 | } |
226 | ||
292b1d17 | 227 | for (retry = 0; retry < sizeof(backoff_ms) / sizeof(backoff_ms[0]); retry++) { |
fcaef9c7 | 228 | fd = lxc_abstract_unix_connect(addr.sun_path); |
94bc08e9 | 229 | if (fd != -1 || errno != ECONNREFUSED) |
e51d4895 | 230 | break; |
fcaef9c7 | 231 | ERROR("Failed to connect to monitor socket. Retrying in %d ms: %s", backoff_ms[retry], strerror(errno)); |
e51d4895 | 232 | usleep(backoff_ms[retry] * 1000); |
0ad19a3f | 233 | } |
234 | ||
fcaef9c7 | 235 | if (fd < 0) { |
292b1d17 | 236 | ERROR("Failed to connect to monitor socket: %s.", strerror(errno)); |
c8dcf778 | 237 | return -1; |
e51d4895 | 238 | } |
292b1d17 | 239 | |
0ad19a3f | 240 | return fd; |
241 | } | |
242 | ||
2366b8a7 | 243 | int lxc_monitor_read_fdset(struct pollfd *fds, nfds_t nfds, struct lxc_msg *msg, |
8d06bd13 | 244 | int timeout) |
0ad19a3f | 245 | { |
2366b8a7 SH |
246 | long i; |
247 | int ret; | |
0ad19a3f | 248 | |
2366b8a7 | 249 | ret = poll(fds, nfds, timeout * 1000); |
8d06bd13 | 250 | if (ret == -1) |
75b1e198 | 251 | return -1; |
8d06bd13 | 252 | else if (ret == 0) |
1a0e70ac | 253 | return -2; /* timed out */ |
8d06bd13 | 254 | |
292b1d17 CB |
255 | /* Only read from the first ready fd, the others will remain ready for |
256 | * when this routine is called again. | |
8d06bd13 DE |
257 | */ |
258 | for (i = 0; i < nfds; i++) { | |
2366b8a7 SH |
259 | if (fds[i].revents != 0) { |
260 | fds[i].revents = 0; | |
261 | ret = recv(fds[i].fd, msg, sizeof(*msg), 0); | |
8d06bd13 | 262 | if (ret <= 0) { |
292b1d17 | 263 | SYSERROR("Failed to receive message. Did monitord die?: %s.", strerror(errno)); |
8d06bd13 DE |
264 | return -1; |
265 | } | |
266 | return ret; | |
267 | } | |
0ad19a3f | 268 | } |
292b1d17 CB |
269 | |
270 | SYSERROR("No ready fd found."); | |
271 | ||
8d06bd13 DE |
272 | return -1; |
273 | } | |
274 | ||
275 | int lxc_monitor_read_timeout(int fd, struct lxc_msg *msg, int timeout) | |
276 | { | |
2366b8a7 | 277 | struct pollfd fds; |
8d06bd13 | 278 | |
2366b8a7 SH |
279 | fds.fd = fd; |
280 | fds.events = POLLIN | POLLPRI; | |
281 | fds.revents = 0; | |
8d06bd13 | 282 | |
2366b8a7 | 283 | return lxc_monitor_read_fdset(&fds, 1, msg, timeout); |
0ad19a3f | 284 | } |
285 | ||
72d0e1cb SG |
286 | int lxc_monitor_read(int fd, struct lxc_msg *msg) |
287 | { | |
288 | return lxc_monitor_read_timeout(fd, msg, -1); | |
289 | } | |
290 | ||
45e854dc | 291 | #define LXC_MONITORD_PATH LIBEXECDIR "/lxc/lxc-monitord" |
e51d4895 | 292 | |
292b1d17 CB |
293 | /* Used to spawn a monitord either on startup of a daemon container, or when |
294 | * lxc-monitor starts. | |
e51d4895 DE |
295 | */ |
296 | int lxc_monitord_spawn(const char *lxcpath) | |
0ad19a3f | 297 | { |
487b14b6 | 298 | int ret; |
e51d4895 | 299 | int pipefd[2]; |
eab15c1e | 300 | char pipefd_str[LXC_NUMSTRLEN64]; |
487b14b6 | 301 | pid_t pid1, pid2; |
e51d4895 | 302 | |
292b1d17 CB |
303 | char *const args[] = { |
304 | LXC_MONITORD_PATH, | |
305 | (char *)lxcpath, | |
306 | pipefd_str, | |
307 | NULL, | |
e51d4895 DE |
308 | }; |
309 | ||
310 | /* double fork to avoid zombies when monitord exits */ | |
311 | pid1 = fork(); | |
312 | if (pid1 < 0) { | |
292b1d17 | 313 | SYSERROR("Failed to fork()."); |
e51d4895 DE |
314 | return -1; |
315 | } | |
316 | ||
317 | if (pid1) { | |
292b1d17 | 318 | DEBUG("Going to wait for pid %d.", pid1); |
f2bbe86d DE |
319 | if (waitpid(pid1, NULL, 0) != pid1) |
320 | return -1; | |
487b14b6 | 321 | DEBUG("Finished waiting on pid %d.", pid1); |
e51d4895 DE |
322 | return 0; |
323 | } | |
324 | ||
325 | if (pipe(pipefd) < 0) { | |
292b1d17 | 326 | SYSERROR("Failed to create pipe."); |
e51d4895 DE |
327 | exit(EXIT_FAILURE); |
328 | } | |
329 | ||
330 | pid2 = fork(); | |
331 | if (pid2 < 0) { | |
292b1d17 | 332 | SYSERROR("Failed to fork()."); |
e51d4895 DE |
333 | exit(EXIT_FAILURE); |
334 | } | |
292b1d17 | 335 | |
e51d4895 | 336 | if (pid2) { |
5cc0f22d | 337 | DEBUG("Trying to sync with child process."); |
e51d4895 | 338 | char c; |
292b1d17 | 339 | /* Wait for daemon to create socket. */ |
e51d4895 | 340 | close(pipefd[1]); |
292b1d17 CB |
341 | |
342 | /* Sync with child, we're ignoring the return from read | |
e51d4895 DE |
343 | * because regardless if it works or not, either way we've |
344 | * synced with the child process. the if-empty-statement | |
345 | * construct is to quiet the warn-unused-result warning. | |
346 | */ | |
8f47bc3f SG |
347 | if (read(pipefd[0], &c, 1)) |
348 | ; | |
292b1d17 | 349 | |
e51d4895 | 350 | close(pipefd[0]); |
292b1d17 | 351 | |
073000e2 | 352 | DEBUG("Successfully synced with child process."); |
e51d4895 DE |
353 | exit(EXIT_SUCCESS); |
354 | } | |
355 | ||
e51d4895 | 356 | if (setsid() < 0) { |
292b1d17 | 357 | SYSERROR("Failed to setsid()."); |
e51d4895 DE |
358 | exit(EXIT_FAILURE); |
359 | } | |
292b1d17 | 360 | |
47a46cf1 | 361 | lxc_check_inherited(NULL, true, &pipefd[1], 1); |
aec1ea62 CB |
362 | if (null_stdfds() < 0) { |
363 | SYSERROR("Failed to dup2() standard file descriptors to /dev/null."); | |
69aeabac | 364 | exit(EXIT_FAILURE); |
aec1ea62 | 365 | } |
292b1d17 | 366 | |
e51d4895 | 367 | close(pipefd[0]); |
292b1d17 | 368 | |
eab15c1e CB |
369 | ret = snprintf(pipefd_str, LXC_NUMSTRLEN64, "%d", pipefd[1]); |
370 | if (ret < 0 || ret >= LXC_NUMSTRLEN64) { | |
aec1ea62 | 371 | ERROR("Failed to create pid argument to pass to monitord."); |
487b14b6 | 372 | exit(EXIT_FAILURE); |
aec1ea62 | 373 | } |
487b14b6 CB |
374 | |
375 | DEBUG("Using pipe file descriptor %d for monitord.", pipefd[1]); | |
292b1d17 | 376 | |
e51d4895 | 377 | execvp(args[0], args); |
00cccc8b | 378 | SYSERROR("failed to exec lxc-monitord"); |
292b1d17 | 379 | |
e51d4895 | 380 | exit(EXIT_FAILURE); |
0ad19a3f | 381 | } |