Add recv fds function to lttng-comm API
[lttng-tools.git] / liblttng-sessiond-comm / lttng-sessiond-comm.c
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1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
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3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
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6 * as published by the Free Software Foundation; only version 2
7 * of the License.
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8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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17 */
18
19#define _GNU_SOURCE
1e307fab 20#include <assert.h>
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21#include <limits.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <sys/socket.h>
26#include <sys/stat.h>
27#include <sys/types.h>
28#include <sys/un.h>
29#include <unistd.h>
30
e88129fc 31#include <lttng-sessiond-comm.h>
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32
33/*
34 * Human readable error message.
35 */
36static const char *lttcomm_readable_code[] = {
37 [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
38 [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
39 [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
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40 [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
41 [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
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42 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
43 [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
e065084a 44 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
f3ed775e 45 [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
ce3d728c 46 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
ca95a216 47 [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
df0da139 48 [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
379473d2 49 [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
520ff687 50 [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
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51 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
52 [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
27673bb6 53 [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
d9800920 54 [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
2b0bf864 55 [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
20fe2104 56 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
7d29a247 57 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
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58 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
59 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
f3ed775e 60 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
26cc6b4e 61 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
d36b8583 62 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
d65106b1 63 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
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64 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
65 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
aaf26714 66 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
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67 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
68 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
69 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
70 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
71 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
72 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
84291629 73 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
2ef84c95 74 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
0177d773 75 [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
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76 [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
77 [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
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78 [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
79 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
80 [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
81 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
82 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
83 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
84 [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
85 [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
86 [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
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87 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
88 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
89 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
90 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
d65106b1 91 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
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92};
93
94/*
95 * lttcom_get_readable_code
96 *
97 * Return ptr to string representing a human readable
98 * error code from the lttcomm_return_code enum.
99 *
100 * These code MUST be negative in other to treat that
101 * as an error value.
102 */
103const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
104{
105 int tmp_code = -code;
106
107 if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
108 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
109 }
110
111 return "Unknown error code";
112}
113
114/*
115 * lttcomm_connect_unix_sock
116 *
117 * Connect to unix socket using the path name.
118 */
119int lttcomm_connect_unix_sock(const char *pathname)
120{
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121 struct sockaddr_un sun;
122 int fd;
a8afeb4a 123 int ret;
fac6795d 124
686204ab 125 fd = socket(PF_UNIX, SOCK_STREAM, 0);
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126 if (fd < 0) {
127 perror("socket");
a8afeb4a 128 ret = fd;
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129 goto error;
130 }
131
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132 memset(&sun, 0, sizeof(sun));
133 sun.sun_family = AF_UNIX;
134 strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0 135 sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d 136
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137 ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
138 if (ret < 0) {
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139 /*
140 * Don't print message on connect error, because connect
141 * is used in normal execution to detect if sessiond is
142 * alive.
143 */
144 goto error_connect;
686204ab 145 }
fac6795d 146
686204ab 147 return fd;
fac6795d 148
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149error_connect:
150 close(fd);
fac6795d 151error:
a8afeb4a 152 return ret;
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153}
154
155/*
156 * lttcomm_accept_unix_sock
157 *
158 * Do an accept(2) on the sock and return the
159 * new file descriptor. The socket MUST be bind(2) before.
160 */
161int lttcomm_accept_unix_sock(int sock)
162{
163 int new_fd;
164 struct sockaddr_un sun;
165 socklen_t len = 0;
166
167 /* Blocking call */
168 new_fd = accept(sock, (struct sockaddr *) &sun, &len);
169 if (new_fd < 0) {
170 perror("accept");
171 goto error;
172 }
173
174 return new_fd;
175
176error:
177 return -1;
178}
179
180/*
181 * lttcomm_create_unix_sock
182 *
183 * Creates a AF_UNIX local socket using pathname
184 * bind the socket upon creation and return the fd.
185 */
186int lttcomm_create_unix_sock(const char *pathname)
187{
188 struct sockaddr_un sun;
189 int fd;
190 int ret = -1;
191
192 /* Create server socket */
193 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
194 perror("socket");
195 goto error;
196 }
197
198 memset(&sun, 0, sizeof(sun));
199 sun.sun_family = AF_UNIX;
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200 strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
201 sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d 202
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203 /* Unlink the old file if present */
204 (void) unlink(pathname);
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205 ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
206 if (ret < 0) {
207 perror("bind");
208 goto error;
209 }
210
211 return fd;
212
213error:
214 return ret;
215}
216
217/*
218 * lttcomm_listen_unix_sock
219 *
220 * Make the socket listen using MAX_LISTEN.
221 */
222int lttcomm_listen_unix_sock(int sock)
223{
224 int ret;
225
226 ret = listen(sock, MAX_LISTEN);
227 if (ret < 0) {
228 perror("listen");
229 }
230
231 return ret;
232}
233
234/*
235 * lttcomm_recv_unix_sock
236 *
237 * Receive data of size len in put that data into
238 * the buf param. Using recvmsg API.
239 * Return the size of received data.
240 */
241ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
242{
159c7ff4 243 struct msghdr msg = { 0 };
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244 struct iovec iov[1];
245 ssize_t ret = -1;
246
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247 iov[0].iov_base = buf;
248 iov[0].iov_len = len;
249 msg.msg_iov = iov;
250 msg.msg_iovlen = 1;
251
252 ret = recvmsg(sock, &msg, 0);
253 if (ret < 0) {
254 perror("recvmsg");
255 }
256
257 return ret;
258}
259
260/*
261 * lttcomm_send_unix_sock
262 *
263 * Send buf data of size len. Using sendmsg API.
264 * Return the size of sent data.
265 */
266ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
267{
159c7ff4 268 struct msghdr msg = { 0 };
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269 struct iovec iov[1];
270 ssize_t ret = -1;
271
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272 iov[0].iov_base = buf;
273 iov[0].iov_len = len;
274 msg.msg_iov = iov;
275 msg.msg_iovlen = 1;
276
277 ret = sendmsg(sock, &msg, 0);
278 if (ret < 0) {
279 perror("sendmsg");
280 }
281
282 return ret;
283}
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284
285/*
286 * lttcomm_close_unix_sock
287 *
288 * Shutdown cleanly a unix socket.
289 */
290int lttcomm_close_unix_sock(int sock)
291{
292 int ret;
293
294 /* Shutdown receptions and transmissions */
295 ret = shutdown(sock, SHUT_RDWR);
296 if (ret < 0) {
297 perror("shutdown");
298 }
299
300 return ret;
301}
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302
303/*
304 * lttcomm_send_fds_unix_sock
305 *
306 * Send multiple fds on a unix socket.
307 */
308ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
309{
159c7ff4 310 struct msghdr msg = { 0 };
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311 struct cmsghdr *cmptr;
312 struct iovec iov[1];
313 ssize_t ret = -1;
314 unsigned int sizeof_fds = nb_fd * sizeof(int);
315 char tmp[CMSG_SPACE(sizeof_fds)];
316
159c7ff4 317 /*
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318 * Note: the consumerd receiver only supports receiving one FD per
319 * message.
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320 */
321 assert(nb_fd == 1);
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322
323 msg.msg_control = (caddr_t)tmp;
324 msg.msg_controllen = CMSG_LEN(sizeof_fds);
325
326 cmptr = CMSG_FIRSTHDR(&msg);
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327 cmptr->cmsg_level = SOL_SOCKET;
328 cmptr->cmsg_type = SCM_RIGHTS;
159c7ff4 329 cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
8c0faa1d 330 memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
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331 /* Sum of the length of all control messages in the buffer: */
332 msg.msg_controllen = cmptr->cmsg_len;
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333
334 iov[0].iov_base = buf;
335 iov[0].iov_len = len;
336 msg.msg_iov = iov;
337 msg.msg_iovlen = 1;
338
339 ret = sendmsg(sock, &msg, 0);
340 if (ret < 0) {
341 perror("sendmsg");
342 }
343
344 return ret;
345}
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346
347/*
348 * Receives a single fd from socket.
349 *
350 * Returns the size of received data
351 */
352ssize_t lttcomm_recv_fds_unix_sock(int sock, void *buf, int *fds,
353 size_t nb_fd, size_t len)
354{
355 struct iovec iov[1];
356 int data_fd, i, ret = 0;
357 struct cmsghdr *cmsg;
358 char recv_fd[CMSG_SPACE(sizeof(int))];
359 struct msghdr msg = { 0 };
360 union {
361 unsigned char vc[4];
362 int vi;
363 } tmp;
364
365 /* Prepare to receive the structures */
366 iov[0].iov_base = &data_fd;
367 iov[0].iov_len = sizeof(data_fd);
368 msg.msg_iov = iov;
369 msg.msg_iovlen = 1;
370 msg.msg_control = recv_fd;
371 msg.msg_controllen = sizeof(recv_fd);
372
373 ret = recvmsg(sock, &msg, 0);
374 if (ret < 0) {
375 perror("recvmsg fds");
376 goto end;
377 }
378
379 if (ret != sizeof(data_fd)) {
380 fprintf(stderr, "Error: Received %d bytes, expected %ld",
381 ret, sizeof(data_fd));
382 goto end;
383 }
384
385 cmsg = CMSG_FIRSTHDR(&msg);
386 if (!cmsg) {
387 fprintf(stderr, "Error: Invalid control message header");
388 ret = -1;
389 goto end;
390 }
391
392 if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
393 fprintf(stderr, "Didn't received any fd");
394 ret = -1;
395 goto end;
396 }
397
398 /* this is our fd */
399 for (i = 0; i < sizeof(int); i++) {
400 tmp.vc[i] = CMSG_DATA(cmsg)[i];
401 }
402
403 ret = tmp.vi;
404
405end:
406 return ret;
407}
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