31d2c6b0 |
1 | /* libltt |
2 | * |
3 | * Linux Trace Toolkit Netlink Control Library |
4 | * |
5 | * Controls the ltt-control kernel module through a netlink socket. |
6 | * |
7 | * Heavily inspired from libipq.c (iptables) made by |
8 | * James Morris <jmorris@intercode.com.au> |
9 | * |
10 | * Copyright 2005 - |
11 | * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
12 | * |
13 | * |
14 | * This program is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * This program is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | */ |
25 | |
264cbffe |
26 | #include <libltt/libltt.h> |
ace0e68d |
27 | #include <errno.h> |
28 | #include <stdio.h> |
31d2c6b0 |
29 | |
c589e8b1 |
30 | |
31d2c6b0 |
31 | /* Private interface */ |
32 | |
33 | enum { |
34 | LTTCTL_ERR_NONE = 0, |
35 | LTTCTL_ERR_IMPL, |
36 | LTTCTL_ERR_HANDLE, |
37 | LTTCTL_ERR_SOCKET, |
38 | LTTCTL_ERR_BIND, |
39 | LTTCTL_ERR_BUFFER, |
40 | LTTCTL_ERR_RECV, |
41 | LTTCTL_ERR_NLEOF, |
42 | LTTCTL_ERR_ADDRLEN, |
43 | LTTCTL_ERR_STRUNC, |
44 | LTTCTL_ERR_RTRUNC, |
45 | LTTCTL_ERR_NLRECV, |
46 | LTTCTL_ERR_SEND, |
47 | LTTCTL_ERR_SUPP, |
48 | LTTCTL_ERR_RECVBUF, |
49 | LTTCTL_ERR_TIMEOUT, |
50 | LTTCTL_ERR_PROTOCOL |
51 | }; |
52 | #define LTTCTL_MAXERR LTTCTL_ERR_PROTOCOL |
53 | |
54 | |
55 | struct lttctl_errmap_t { |
56 | int errcode; |
57 | char *message; |
58 | } lttctl_errmap[] = { |
ace0e68d |
59 | { LTTCTL_ERR_NONE, "Unknown error" }, |
60 | { LTTCTL_ERR_IMPL, "Implementation error" }, |
61 | { LTTCTL_ERR_HANDLE, "Unable to create netlink handle" }, |
62 | { LTTCTL_ERR_SOCKET, "Unable to create netlink socket" }, |
63 | { LTTCTL_ERR_BIND, "Unable to bind netlink socket" }, |
64 | { LTTCTL_ERR_BUFFER, "Unable to allocate buffer" }, |
65 | { LTTCTL_ERR_RECV, "Failed to receive netlink message" }, |
66 | { LTTCTL_ERR_NLEOF, "Received EOF on netlink socket" }, |
67 | { LTTCTL_ERR_ADDRLEN, "Invalid peer address length" }, |
68 | { LTTCTL_ERR_STRUNC, "Sent message truncated" }, |
69 | { LTTCTL_ERR_RTRUNC, "Received message truncated" }, |
70 | { LTTCTL_ERR_NLRECV, "Received error from netlink" }, |
71 | { LTTCTL_ERR_SEND, "Failed to send netlink message" }, |
72 | { LTTCTL_ERR_SUPP, "Operation not supported" }, |
73 | { LTTCTL_ERR_RECVBUF, "Receive buffer size invalid" }, |
74 | { LTTCTL_ERR_TIMEOUT, "Timeout"}, |
75 | { LTTCTL_ERR_PROTOCOL, "Invalid protocol specified" } |
31d2c6b0 |
76 | }; |
77 | |
78 | static int lttctl_errno = LTTCTL_ERR_NONE; |
79 | |
80 | |
81 | static ssize_t lttctl_netlink_sendto(const struct lttctl_handle *h, |
82 | const void *msg, size_t len); |
83 | |
84 | static ssize_t lttctl_netlink_recvfrom(const struct lttctl_handle *h, |
85 | unsigned char *buf, size_t len, |
86 | int timeout); |
87 | |
88 | static ssize_t lttctl_netlink_sendmsg(const struct lttctl_handle *h, |
89 | const struct msghdr *msg, |
90 | unsigned int flags); |
91 | |
92 | static char *lttctl_strerror(int errcode); |
93 | |
ace0e68d |
94 | void lttctl_perror(const char *s); |
95 | |
31d2c6b0 |
96 | static ssize_t lttctl_netlink_sendto(const struct lttctl_handle *h, |
97 | const void *msg, size_t len) |
98 | { |
99 | int status = sendto(h->fd, msg, len, 0, |
100 | (struct sockaddr *)&h->peer, sizeof(h->peer)); |
101 | if (status < 0) |
102 | lttctl_errno = LTTCTL_ERR_SEND; |
ace0e68d |
103 | |
31d2c6b0 |
104 | return status; |
105 | } |
106 | |
107 | static ssize_t lttctl_netlink_sendmsg(const struct lttctl_handle *h, |
108 | const struct msghdr *msg, |
109 | unsigned int flags) |
110 | { |
111 | int status = sendmsg(h->fd, msg, flags); |
112 | if (status < 0) |
113 | lttctl_errno = LTTCTL_ERR_SEND; |
114 | return status; |
115 | } |
116 | |
117 | static ssize_t lttctl_netlink_recvfrom(const struct lttctl_handle *h, |
118 | unsigned char *buf, size_t len, |
119 | int timeout) |
120 | { |
121 | int addrlen, status; |
122 | struct nlmsghdr *nlh; |
123 | |
ace0e68d |
124 | if (len < sizeof(struct nlmsghdr)) { |
31d2c6b0 |
125 | lttctl_errno = LTTCTL_ERR_RECVBUF; |
ace0e68d |
126 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
127 | return -1; |
128 | } |
129 | addrlen = sizeof(h->peer); |
130 | |
131 | if (timeout != 0) { |
132 | int ret; |
133 | struct timeval tv; |
134 | fd_set read_fds; |
135 | |
136 | if (timeout < 0) { |
137 | /* non-block non-timeout */ |
138 | tv.tv_sec = 0; |
139 | tv.tv_usec = 0; |
140 | } else { |
141 | tv.tv_sec = timeout / 1000000; |
142 | tv.tv_usec = timeout % 1000000; |
143 | } |
144 | |
145 | FD_ZERO(&read_fds); |
146 | FD_SET(h->fd, &read_fds); |
147 | ret = select(h->fd+1, &read_fds, NULL, NULL, &tv); |
148 | if (ret < 0) { |
149 | if (errno == EINTR) { |
ace0e68d |
150 | printf("eintr\n"); |
31d2c6b0 |
151 | return 0; |
152 | } else { |
ace0e68d |
153 | lttctl_errno = LTTCTL_ERR_RECV; |
154 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
155 | return -1; |
156 | } |
157 | } |
158 | if (!FD_ISSET(h->fd, &read_fds)) { |
ace0e68d |
159 | lttctl_errno = LTTCTL_ERR_TIMEOUT; |
160 | printf("timeout\n"); |
31d2c6b0 |
161 | return 0; |
162 | } |
163 | } |
164 | status = recvfrom(h->fd, buf, len, 0, |
165 | (struct sockaddr *)&h->peer, &addrlen); |
ace0e68d |
166 | |
31d2c6b0 |
167 | if (status < 0) { |
168 | lttctl_errno = LTTCTL_ERR_RECV; |
ace0e68d |
169 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
170 | return status; |
171 | } |
172 | if (addrlen != sizeof(h->peer)) { |
173 | lttctl_errno = LTTCTL_ERR_RECV; |
ace0e68d |
174 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
175 | return -1; |
176 | } |
177 | if (h->peer.nl_pid != 0) { |
178 | lttctl_errno = LTTCTL_ERR_RECV; |
ace0e68d |
179 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
180 | return -1; |
181 | } |
182 | if (status == 0) { |
183 | lttctl_errno = LTTCTL_ERR_NLEOF; |
ace0e68d |
184 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
185 | return -1; |
186 | } |
187 | nlh = (struct nlmsghdr *)buf; |
188 | if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) { |
189 | lttctl_errno = LTTCTL_ERR_RTRUNC; |
ace0e68d |
190 | lttctl_perror("Netlink recvfrom"); |
31d2c6b0 |
191 | return -1; |
192 | } |
ace0e68d |
193 | |
194 | |
31d2c6b0 |
195 | return status; |
196 | } |
197 | |
198 | |
199 | static char *lttctl_strerror(int errcode) |
200 | { |
201 | if (errcode < 0 || errcode > LTTCTL_MAXERR) |
202 | errcode = LTTCTL_ERR_IMPL; |
203 | return lttctl_errmap[errcode].message; |
204 | } |
205 | |
206 | |
ace0e68d |
207 | char *lttctl_errstr(void) |
208 | { |
209 | return lttctl_strerror(lttctl_errno); |
210 | } |
211 | |
212 | void lttctl_perror(const char *s) |
213 | { |
214 | if (s) |
215 | fputs(s, stderr); |
216 | else |
217 | fputs("ERROR", stderr); |
218 | if (lttctl_errno) |
219 | fprintf(stderr, ": %s", lttctl_errstr()); |
220 | if (errno) |
221 | fprintf(stderr, ": %s", strerror(errno)); |
222 | fputc('\n', stderr); |
223 | } |
31d2c6b0 |
224 | |
225 | /* public interface */ |
226 | |
227 | /* |
228 | * Create and initialise an lttctl handle. |
229 | */ |
230 | struct lttctl_handle *lttctl_create_handle(void) |
231 | { |
232 | int status; |
233 | struct lttctl_handle *h; |
234 | |
235 | h = (struct lttctl_handle *)malloc(sizeof(struct lttctl_handle)); |
236 | if (h == NULL) { |
ace0e68d |
237 | lttctl_errno = LTTCTL_ERR_HANDLE; |
238 | lttctl_perror("Create handle"); |
239 | goto alloc_error; |
31d2c6b0 |
240 | } |
241 | |
242 | memset(h, 0, sizeof(struct lttctl_handle)); |
243 | |
244 | h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_LTT); |
245 | |
246 | if (h->fd == -1) { |
247 | lttctl_errno = LTTCTL_ERR_SOCKET; |
ace0e68d |
248 | lttctl_perror("Create handle"); |
249 | goto socket_error; |
31d2c6b0 |
250 | } |
251 | memset(&h->local, 0, sizeof(struct sockaddr_nl)); |
252 | h->local.nl_family = AF_NETLINK; |
253 | h->local.nl_pid = getpid(); |
254 | h->local.nl_groups = 0; |
255 | status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local)); |
256 | if (status == -1) { |
257 | lttctl_errno = LTTCTL_ERR_BIND; |
ace0e68d |
258 | lttctl_perror("Create handle"); |
259 | goto bind_error; |
31d2c6b0 |
260 | } |
261 | memset(&h->peer, 0, sizeof(struct sockaddr_nl)); |
262 | h->peer.nl_family = AF_NETLINK; |
263 | h->peer.nl_pid = 0; |
264 | h->peer.nl_groups = 0; |
265 | return h; |
ace0e68d |
266 | |
267 | /* Error condition */ |
268 | bind_error: |
269 | socket_error: |
270 | close(h->fd); |
271 | alloc_error: |
272 | free(h); |
273 | return NULL; |
31d2c6b0 |
274 | } |
275 | |
276 | /* |
277 | * No error condition is checked here at this stage, but it may happen |
278 | * if/when reliable messaging is implemented. |
279 | */ |
280 | int lttctl_destroy_handle(struct lttctl_handle *h) |
281 | { |
282 | if (h) { |
283 | close(h->fd); |
284 | free(h); |
285 | } |
286 | return 0; |
287 | } |
288 | |
289 | |
ace0e68d |
290 | int lttctl_create_trace(const struct lttctl_handle *h, |
31d2c6b0 |
291 | char *name, enum trace_mode mode) |
292 | { |
ace0e68d |
293 | int err; |
294 | |
31d2c6b0 |
295 | struct { |
296 | struct nlmsghdr nlh; |
297 | lttctl_peer_msg_t msg; |
298 | } req; |
ace0e68d |
299 | struct { |
300 | struct nlmsghdr nlh; |
301 | struct nlmsgerr nlerr; |
302 | lttctl_peer_msg_t msg; |
303 | } ack; |
31d2c6b0 |
304 | |
305 | memset(&req, 0, sizeof(req)); |
ace0e68d |
306 | req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); |
307 | req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK; |
31d2c6b0 |
308 | req.nlh.nlmsg_type = LTTCTLM_CONTROL; |
309 | req.nlh.nlmsg_pid = h->local.nl_pid; |
ace0e68d |
310 | req.nlh.nlmsg_seq = 0; |
31d2c6b0 |
311 | |
312 | strncpy(req.msg.trace_name, name, NAME_MAX); |
313 | req.msg.op = OP_CREATE; |
314 | req.msg.args.mode = mode; |
315 | |
ace0e68d |
316 | err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); |
317 | if(err < 0) goto senderr; |
318 | |
319 | err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); |
320 | if(err < 0) goto senderr; |
321 | |
322 | err = ack.nlerr.error; |
323 | if(err != 0) { |
324 | errno = err; |
325 | lttctl_perror("Create Trace Error"); |
326 | return -1; |
327 | } |
328 | |
329 | return 0; |
330 | |
331 | senderr: |
332 | lttctl_perror("Create Trace Error"); |
333 | return err; |
31d2c6b0 |
334 | } |
335 | |
ace0e68d |
336 | int lttctl_destroy_trace(const struct lttctl_handle *h, |
31d2c6b0 |
337 | char *name) |
338 | { |
339 | struct { |
340 | struct nlmsghdr nlh; |
341 | lttctl_peer_msg_t msg; |
342 | } req; |
ace0e68d |
343 | struct { |
344 | struct nlmsghdr nlh; |
345 | struct nlmsgerr nlerr; |
346 | lttctl_peer_msg_t msg; |
347 | } ack; |
348 | int err; |
31d2c6b0 |
349 | |
350 | memset(&req, 0, sizeof(req)); |
ace0e68d |
351 | req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); |
31d2c6b0 |
352 | req.nlh.nlmsg_flags = NLM_F_REQUEST; |
353 | req.nlh.nlmsg_type = LTTCTLM_CONTROL; |
354 | req.nlh.nlmsg_pid = h->local.nl_pid; |
355 | |
356 | strncpy(req.msg.trace_name, name, NAME_MAX); |
357 | req.msg.op = OP_DESTROY; |
358 | |
ace0e68d |
359 | err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); |
360 | if(err < 0) goto senderr; |
361 | |
362 | err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); |
363 | if(err < 0) goto senderr; |
364 | |
365 | err = ack.nlerr.error; |
366 | if(err != 0) { |
367 | errno = err; |
368 | lttctl_perror("Destroy Trace Channels Error"); |
369 | return -1; |
370 | } |
371 | |
372 | return 0; |
373 | |
374 | senderr: |
375 | lttctl_perror("Destroy Trace Channels Error"); |
376 | return err; |
377 | |
31d2c6b0 |
378 | } |
379 | |
ace0e68d |
380 | int lttctl_start(const struct lttctl_handle *h, |
31d2c6b0 |
381 | char *name) |
382 | { |
383 | struct { |
384 | struct nlmsghdr nlh; |
385 | lttctl_peer_msg_t msg; |
386 | } req; |
ace0e68d |
387 | struct { |
388 | struct nlmsghdr nlh; |
389 | struct nlmsgerr nlerr; |
390 | lttctl_peer_msg_t msg; |
391 | } ack; |
392 | |
393 | int err; |
31d2c6b0 |
394 | |
395 | memset(&req, 0, sizeof(req)); |
ace0e68d |
396 | req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); |
31d2c6b0 |
397 | req.nlh.nlmsg_flags = NLM_F_REQUEST; |
398 | req.nlh.nlmsg_type = LTTCTLM_CONTROL; |
399 | req.nlh.nlmsg_pid = h->local.nl_pid; |
400 | |
401 | strncpy(req.msg.trace_name, name, NAME_MAX); |
402 | req.msg.op = OP_START; |
403 | |
ace0e68d |
404 | err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); |
405 | if(err < 0) goto senderr; |
406 | |
407 | err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); |
408 | if(err < 0) goto senderr; |
409 | |
410 | err = ack.nlerr.error; |
411 | if(err != 0) { |
412 | errno = err; |
413 | lttctl_perror("Start Trace Error"); |
414 | return -1; |
415 | } |
416 | |
417 | return 0; |
418 | |
419 | senderr: |
420 | lttctl_perror("Start Trace Error"); |
421 | return err; |
422 | |
31d2c6b0 |
423 | } |
424 | |
ace0e68d |
425 | int lttctl_stop(const struct lttctl_handle *h, |
31d2c6b0 |
426 | char *name) |
427 | { |
428 | struct { |
429 | struct nlmsghdr nlh; |
430 | lttctl_peer_msg_t msg; |
431 | } req; |
ace0e68d |
432 | struct { |
433 | struct nlmsghdr nlh; |
434 | struct nlmsgerr nlerr; |
435 | lttctl_peer_msg_t msg; |
436 | } ack; |
437 | int err; |
31d2c6b0 |
438 | |
439 | memset(&req, 0, sizeof(req)); |
ace0e68d |
440 | req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); |
31d2c6b0 |
441 | req.nlh.nlmsg_flags = NLM_F_REQUEST; |
442 | req.nlh.nlmsg_type = LTTCTLM_CONTROL; |
443 | req.nlh.nlmsg_pid = h->local.nl_pid; |
444 | |
445 | strncpy(req.msg.trace_name, name, NAME_MAX); |
446 | req.msg.op = OP_STOP; |
447 | |
ace0e68d |
448 | err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); |
449 | if(err < 0) goto senderr; |
450 | |
451 | err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); |
452 | if(err < 0) goto senderr; |
453 | |
454 | err = ack.nlerr.error; |
455 | if(err != 0) { |
456 | errno = err; |
457 | lttctl_perror("Stop Trace Error"); |
458 | return -1; |
459 | } |
460 | |
461 | return 0; |
462 | |
463 | senderr: |
464 | lttctl_perror("Stop Trace Error"); |
465 | return err; |
31d2c6b0 |
466 | } |