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4c17b2e3 DC |
1 | /* |
2 | ||
3 | Copyright (C) 2018 Proxmox Server Solutions GmbH | |
4 | ||
f4ced5d2 | 5 | Copyright: qmeventd is under GNU GPL, the GNU General Public License. |
4c17b2e3 DC |
6 | |
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; version 2 dated June, 1991. | |
10 | ||
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. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA | |
19 | 02111-1307, USA. | |
20 | ||
21 | Author: Dominik Csapak <d.csapak@proxmox.com> | |
22 | ||
23 | qmeventd listens on a given socket, and waits for qemu processes | |
24 | to connect | |
25 | ||
26 | it then waits for shutdown events followed by the closing of the socket, | |
27 | it then calls /usr/sbin/qm cleanup with following arguments | |
28 | ||
29 | /usr/sbin/qm cleanup VMID <graceful> <guest> | |
30 | ||
31 | parameter explanation: | |
32 | ||
33 | graceful: | |
34 | 1|0 depending if it saw a shutdown event before the socket closed | |
35 | ||
36 | guest: | |
37 | 1|0 depending if the shutdown was requested from the guest | |
38 | ||
39 | */ | |
40 | ||
41 | #ifndef _GNU_SOURCE | |
42 | #define _GNU_SOURCE | |
43 | #endif | |
44 | ||
45 | #include <errno.h> | |
46 | #include <fcntl.h> | |
47 | #include <json.h> | |
48 | #include <signal.h> | |
49 | #include <stdbool.h> | |
50 | #include <stdio.h> | |
51 | #include <string.h> | |
52 | #include <sys/epoll.h> | |
53 | #include <sys/socket.h> | |
54 | #include <sys/types.h> | |
55 | #include <sys/un.h> | |
56 | #include <sys/wait.h> | |
57 | #include <unistd.h> | |
58 | ||
59 | #include "qmeventd.h" | |
60 | ||
61 | static int verbose = 0; | |
62 | static int epoll_fd = 0; | |
63 | static const char *progname; | |
64 | /* | |
65 | * Helper functions | |
66 | */ | |
67 | ||
68 | static void | |
69 | usage() | |
70 | { | |
71 | fprintf(stderr, "Usage: %s [-f] [-v] PATH\n", progname); | |
72 | fprintf(stderr, " -f run in foreground (default: false)\n"); | |
73 | fprintf(stderr, " -v verbose (default: false)\n"); | |
74 | fprintf(stderr, " PATH use PATH for socket\n"); | |
75 | } | |
76 | ||
77 | static pid_t | |
78 | get_pid_from_fd(int fd) | |
79 | { | |
80 | struct ucred credentials = { .pid = 0, .uid = 0, .gid = 0 }; | |
81 | socklen_t len = sizeof(struct ucred); | |
82 | log_neg(getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &credentials, &len), "getsockopt"); | |
83 | return credentials.pid; | |
84 | } | |
85 | ||
86 | /* | |
87 | * reads the vmid from /proc/<pid>/cmdline | |
88 | * after the '-id' argument | |
89 | */ | |
90 | static unsigned long | |
91 | get_vmid_from_pid(pid_t pid) | |
92 | { | |
93 | char filename[32] = { 0 }; | |
94 | int len = snprintf(filename, sizeof(filename), "/proc/%d/cmdline", pid); | |
95 | if (len < 0) { | |
96 | fprintf(stderr, "error during snprintf for %d: %s\n", pid, | |
97 | strerror(errno)); | |
98 | return 0; | |
99 | } | |
100 | if ((size_t)len >= sizeof(filename)) { | |
101 | fprintf(stderr, "error: pid %d too long\n", pid); | |
102 | return 0; | |
103 | } | |
104 | FILE *fp = fopen(filename, "re"); | |
105 | if (fp == NULL) { | |
106 | fprintf(stderr, "error opening %s: %s\n", filename, strerror(errno)); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | unsigned long vmid = 0; | |
111 | ssize_t rc = 0; | |
112 | char *buf = NULL; | |
113 | size_t buflen = 0; | |
114 | while ((rc = getdelim(&buf, &buflen, '\0', fp)) >= 0) { | |
115 | if (!strcmp(buf, "-id")) { | |
116 | break; | |
117 | } | |
118 | } | |
119 | ||
120 | if (rc < 0) { | |
121 | goto err; | |
122 | } | |
123 | ||
124 | if (getdelim(&buf, &buflen, '\0', fp) >= 0) { | |
125 | if (buf[0] == '-' || buf[0] == '\0') { | |
126 | fprintf(stderr, "invalid vmid %s\n", buf); | |
127 | goto ret; | |
128 | } | |
129 | ||
130 | errno = 0; | |
131 | char *endptr = NULL; | |
132 | vmid = strtoul(buf, &endptr, 10); | |
133 | if (errno != 0) { | |
134 | vmid = 0; | |
135 | goto err; | |
136 | } else if (*endptr != '\0') { | |
137 | fprintf(stderr, "invalid vmid %s\n", buf); | |
138 | vmid = 0; | |
139 | } | |
140 | ||
141 | goto ret; | |
142 | } | |
143 | ||
144 | err: | |
145 | fprintf(stderr, "error parsing vmid for %d: %s\n", pid, strerror(errno)); | |
146 | ||
147 | ret: | |
148 | free(buf); | |
149 | fclose(fp); | |
150 | return vmid; | |
151 | } | |
152 | ||
153 | static bool | |
154 | must_write(int fd, const char *buf, size_t len) | |
155 | { | |
156 | ssize_t wlen; | |
157 | do { | |
158 | wlen = write(fd, buf, len); | |
159 | } while (wlen < 0 && errno == EINTR); | |
160 | ||
161 | return (wlen == (ssize_t)len); | |
162 | } | |
163 | ||
164 | /* | |
165 | * qmp handling functions | |
166 | */ | |
167 | ||
168 | void | |
169 | handle_qmp_handshake(struct Client *client) | |
170 | { | |
171 | VERBOSE_PRINT("%s: got QMP handshake\n", client->vmid); | |
172 | static const char qmp_answer[] = "{\"execute\":\"qmp_capabilities\"}\n"; | |
173 | if (!must_write(client->fd, qmp_answer, sizeof(qmp_answer) - 1)) { | |
174 | fprintf(stderr, "%s: cannot complete handshake\n", client->vmid); | |
175 | cleanup_client(client); | |
176 | } | |
177 | } | |
178 | ||
179 | void | |
180 | handle_qmp_event(struct Client *client, struct json_object *obj) | |
181 | { | |
182 | struct json_object *event; | |
183 | if (!json_object_object_get_ex(obj, "event", &event)) { | |
184 | return; | |
185 | } | |
186 | VERBOSE_PRINT("%s: got QMP event: %s\n", client->vmid, | |
187 | json_object_get_string(event)); | |
188 | // event, check if shutdown and get guest parameter | |
189 | if (!strcmp(json_object_get_string(event), "SHUTDOWN")) { | |
190 | client->graceful = 1; | |
191 | struct json_object *data; | |
192 | struct json_object *guest; | |
193 | if (json_object_object_get_ex(obj, "data", &data) && | |
194 | json_object_object_get_ex(data, "guest", &guest)) | |
195 | { | |
196 | client->guest = (unsigned short)json_object_get_boolean(guest); | |
197 | } | |
198 | } | |
199 | } | |
200 | ||
201 | /* | |
202 | * client management functions | |
203 | */ | |
204 | ||
205 | void | |
206 | add_new_client(int client_fd) | |
207 | { | |
208 | struct Client *client = calloc(sizeof(struct Client), 1); | |
209 | client->fd = client_fd; | |
210 | client->pid = get_pid_from_fd(client_fd); | |
211 | if (client->pid == 0) { | |
212 | fprintf(stderr, "could not get pid from client\n"); | |
213 | goto err; | |
214 | } | |
215 | unsigned long vmid = get_vmid_from_pid(client->pid); | |
216 | int res = snprintf(client->vmid, sizeof(client->vmid), "%lu", vmid); | |
217 | if (vmid == 0 || res < 0 || res >= (int)sizeof(client->vmid)) { | |
218 | fprintf(stderr, "could not get vmid from pid %d\n", client->pid); | |
219 | goto err; | |
220 | } | |
221 | ||
222 | struct epoll_event ev; | |
223 | ev.events = EPOLLIN; | |
224 | ev.data.ptr = client; | |
225 | res = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client_fd, &ev); | |
226 | if (res < 0) { | |
227 | perror("epoll_ctl client add"); | |
228 | goto err; | |
229 | } | |
230 | ||
231 | VERBOSE_PRINT("added new client, pid: %d, vmid: %s\n", client->pid, | |
232 | client->vmid); | |
233 | ||
234 | return; | |
235 | err: | |
236 | (void)close(client_fd); | |
237 | free(client); | |
238 | } | |
239 | ||
240 | void | |
241 | cleanup_client(struct Client *client) | |
242 | { | |
243 | VERBOSE_PRINT("%s: client exited, status: graceful: %d, guest: %d\n", | |
244 | client->vmid, client->graceful, client->guest); | |
245 | log_neg(epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->fd, NULL), "epoll del"); | |
246 | (void)close(client->fd); | |
247 | ||
248 | unsigned short graceful = client->graceful; | |
249 | unsigned short guest = client->guest; | |
250 | char vmid[sizeof(client->vmid)]; | |
251 | strncpy(vmid, client->vmid, sizeof(vmid)); | |
252 | free(client); | |
253 | VERBOSE_PRINT("%s: executing cleanup\n", vmid); | |
254 | ||
255 | int pid = fork(); | |
256 | if (pid < 0) { | |
257 | fprintf(stderr, "fork failed: %s\n", strerror(errno)); | |
258 | return; | |
259 | } | |
260 | if (pid == 0) { | |
261 | char *script = "/usr/sbin/qm"; | |
262 | ||
263 | char *args[] = { | |
264 | script, | |
265 | "cleanup", | |
266 | vmid, | |
267 | graceful ? "1" : "0", | |
268 | guest ? "1" : "0", | |
269 | NULL | |
270 | }; | |
271 | ||
272 | execvp(script, args); | |
273 | perror("execvp"); | |
274 | _exit(1); | |
275 | } | |
276 | } | |
277 | ||
278 | void | |
279 | handle_client(struct Client *client) | |
280 | { | |
281 | VERBOSE_PRINT("%s: entering handle\n", client->vmid); | |
282 | ssize_t len; | |
283 | do { | |
284 | len = read(client->fd, (client->buf+client->buflen), | |
285 | sizeof(client->buf) - client->buflen); | |
286 | } while (len < 0 && errno == EINTR); | |
287 | ||
288 | if (len < 0) { | |
289 | if (!(errno == EAGAIN || errno == EWOULDBLOCK)) { | |
290 | log_neg((int)len, "read"); | |
291 | cleanup_client(client); | |
292 | } | |
293 | return; | |
294 | } else if (len == 0) { | |
295 | VERBOSE_PRINT("%s: got EOF\n", client->vmid); | |
296 | cleanup_client(client); | |
297 | return; | |
298 | } | |
299 | ||
300 | VERBOSE_PRINT("%s: read %ld bytes\n", client->vmid, len); | |
301 | client->buflen += len; | |
302 | ||
303 | struct json_tokener *tok = json_tokener_new(); | |
304 | struct json_object *jobj = NULL; | |
305 | enum json_tokener_error jerr = json_tokener_success; | |
306 | while (jerr == json_tokener_success && client->buflen != 0) { | |
307 | jobj = json_tokener_parse_ex(tok, client->buf, (int)client->buflen); | |
308 | jerr = json_tokener_get_error(tok); | |
309 | unsigned int offset = (unsigned int)tok->char_offset; | |
310 | switch (jerr) { | |
311 | case json_tokener_success: | |
312 | // move rest from buffer to front | |
313 | memmove(client->buf, client->buf + offset, client->buflen - offset); | |
314 | client->buflen -= offset; | |
315 | if (json_object_is_type(jobj, json_type_object)) { | |
316 | struct json_object *obj; | |
317 | if (json_object_object_get_ex(jobj, "QMP", &obj)) { | |
318 | handle_qmp_handshake(client); | |
319 | } else if (json_object_object_get_ex(jobj, "event", &obj)) { | |
320 | handle_qmp_event(client, jobj); | |
321 | } // else ignore message | |
322 | } | |
323 | break; | |
324 | case json_tokener_continue: | |
325 | if (client->buflen >= sizeof(client->buf)) { | |
326 | VERBOSE_PRINT("%s, msg too large, discarding buffer\n", | |
327 | client->vmid); | |
328 | memset(client->buf, 0, sizeof(client->buf)); | |
329 | client->buflen = 0; | |
330 | } // else we have enough space try again after next read | |
331 | break; | |
332 | default: | |
333 | VERBOSE_PRINT("%s: parse error: %d, discarding buffer\n", | |
334 | client->vmid, jerr); | |
335 | memset(client->buf, 0, client->buflen); | |
336 | client->buflen = 0; | |
337 | break; | |
338 | } | |
339 | json_object_put(jobj); | |
340 | } | |
341 | json_tokener_free(tok); | |
342 | } | |
343 | ||
344 | ||
345 | int | |
346 | main(int argc, char *argv[]) | |
347 | { | |
348 | int opt; | |
349 | int daemonize = 1; | |
350 | char *socket_path = NULL; | |
351 | progname = argv[0]; | |
352 | ||
353 | while ((opt = getopt(argc, argv, "hfv")) != -1) { | |
354 | switch (opt) { | |
355 | case 'f': | |
356 | daemonize = 0; | |
357 | break; | |
358 | case 'v': | |
359 | verbose = 1; | |
360 | break; | |
361 | case 'h': | |
362 | usage(); | |
363 | exit(EXIT_SUCCESS); | |
364 | break; | |
365 | default: | |
366 | usage(); | |
367 | exit(EXIT_FAILURE); | |
368 | } | |
369 | } | |
370 | ||
371 | if (optind >= argc) { | |
372 | usage(); | |
373 | exit(EXIT_FAILURE); | |
374 | } | |
375 | ||
376 | signal(SIGCHLD, SIG_IGN); | |
377 | ||
378 | socket_path = argv[optind]; | |
379 | ||
380 | int sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
381 | bail_neg(sock, "socket"); | |
382 | ||
383 | struct sockaddr_un addr; | |
384 | memset(&addr, 0, sizeof(addr)); | |
385 | addr.sun_family = AF_UNIX; | |
386 | strncpy(addr.sun_path, socket_path, sizeof(addr.sun_path) - 1); | |
387 | ||
388 | unlink(socket_path); | |
389 | bail_neg(bind(sock, (struct sockaddr*)&addr, sizeof(addr)), "bind"); | |
390 | ||
391 | struct epoll_event ev, events[1]; | |
392 | epoll_fd = epoll_create1(EPOLL_CLOEXEC); | |
393 | bail_neg(epoll_fd, "epoll_create1"); | |
394 | ||
395 | ev.events = EPOLLIN; | |
396 | ev.data.fd = sock; | |
397 | bail_neg(epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev), "epoll_ctl"); | |
398 | ||
399 | bail_neg(listen(sock, 10), "listen"); | |
400 | ||
401 | if (daemonize) { | |
402 | bail_neg(daemon(0, 1), "daemon"); | |
403 | } | |
404 | ||
405 | int nevents; | |
406 | ||
407 | for(;;) { | |
408 | nevents = epoll_wait(epoll_fd, events, 1, -1); | |
409 | if (nevents < 0 && errno == EINTR) { | |
410 | // signal happened, try again | |
411 | continue; | |
412 | } | |
413 | bail_neg(nevents, "epoll_wait"); | |
414 | ||
415 | for (int n = 0; n < nevents; n++) { | |
416 | if (events[n].data.fd == sock) { | |
417 | ||
418 | int conn_sock = accept4(sock, NULL, NULL, | |
419 | SOCK_NONBLOCK | SOCK_CLOEXEC); | |
420 | log_neg(conn_sock, "accept"); | |
421 | if (conn_sock > -1) { | |
422 | add_new_client(conn_sock); | |
423 | } | |
424 | } else { | |
425 | handle_client((struct Client *)events[n].data.ptr); | |
426 | } | |
427 | } | |
428 | } | |
429 | } |