Fix handling of sessiond respawn after a SIGKILL
[lttng-tools.git] / liblttsessiondcomm / liblttsessiondcomm.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
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
6 * as published by the Free Software Foundation; only version 2
7 * of the License.
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.
17 */
18
19 #define _GNU_SOURCE
20 #include <limits.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/socket.h>
25 #include <sys/stat.h>
26 #include <sys/types.h>
27 #include <sys/un.h>
28 #include <unistd.h>
29 #include <assert.h>
30
31 #include "liblttsessiondcomm.h"
32
33 /*
34 * Human readable error message.
35 */
36 static 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",
40 [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
41 [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
42 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
43 [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
44 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
45 [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
46 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
47 [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
48 [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
49 [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
50 [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
51 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
52 [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
53 [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
54 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
55 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
56 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
57 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
58 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
59 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
60 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
61 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
62 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
63 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
64 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
65 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
66 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
67 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
68 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
69 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
70 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
71 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
72 [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
73 [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
74 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
75 [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
76 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
77 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
78 [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
79 [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
80 [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
81 [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
82 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
83 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
84 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
85 [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
86 [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
87 };
88
89 /*
90 * lttcom_get_readable_code
91 *
92 * Return ptr to string representing a human readable
93 * error code from the lttcomm_return_code enum.
94 *
95 * These code MUST be negative in other to treat that
96 * as an error value.
97 */
98 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
99 {
100 int tmp_code = -code;
101
102 if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
103 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
104 }
105
106 return "Unknown error code";
107 }
108
109 /*
110 * lttcomm_connect_unix_sock
111 *
112 * Connect to unix socket using the path name.
113 */
114 int lttcomm_connect_unix_sock(const char *pathname)
115 {
116 struct sockaddr_un sun;
117 int fd;
118 int ret = 1;
119
120 fd = socket(PF_UNIX, SOCK_STREAM, 0);
121 if (fd < 0) {
122 perror("socket");
123 goto error;
124 }
125
126 memset(&sun, 0, sizeof(sun));
127 sun.sun_family = AF_UNIX;
128 strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
129
130 ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
131 if (ret < 0) {
132 perror("connect");
133 goto error;
134 }
135
136 return fd;
137
138 error:
139 return -1;
140 }
141
142 /*
143 * lttcomm_accept_unix_sock
144 *
145 * Do an accept(2) on the sock and return the
146 * new file descriptor. The socket MUST be bind(2) before.
147 */
148 int lttcomm_accept_unix_sock(int sock)
149 {
150 int new_fd;
151 struct sockaddr_un sun;
152 socklen_t len = 0;
153
154 /* Blocking call */
155 new_fd = accept(sock, (struct sockaddr *) &sun, &len);
156 if (new_fd < 0) {
157 perror("accept");
158 goto error;
159 }
160
161 return new_fd;
162
163 error:
164 return -1;
165 }
166
167 /*
168 * lttcomm_create_unix_sock
169 *
170 * Creates a AF_UNIX local socket using pathname
171 * bind the socket upon creation and return the fd.
172 */
173 int lttcomm_create_unix_sock(const char *pathname)
174 {
175 struct sockaddr_un sun;
176 int fd;
177 int ret = -1;
178
179 /* Create server socket */
180 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
181 perror("socket");
182 goto error;
183 }
184
185 memset(&sun, 0, sizeof(sun));
186 sun.sun_family = AF_UNIX;
187 strncpy(sun.sun_path, pathname, strlen(pathname));
188
189 /* Unlink the old file if present */
190 (void) unlink(pathname);
191 ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
192 if (ret < 0) {
193 perror("bind");
194 goto error;
195 }
196
197 return fd;
198
199 error:
200 return ret;
201 }
202
203 /*
204 * lttcomm_listen_unix_sock
205 *
206 * Make the socket listen using MAX_LISTEN.
207 */
208 int lttcomm_listen_unix_sock(int sock)
209 {
210 int ret;
211
212 ret = listen(sock, MAX_LISTEN);
213 if (ret < 0) {
214 perror("listen");
215 }
216
217 return ret;
218 }
219
220 /*
221 * lttcomm_recv_unix_sock
222 *
223 * Receive data of size len in put that data into
224 * the buf param. Using recvmsg API.
225 * Return the size of received data.
226 */
227 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
228 {
229 struct msghdr msg = { 0 };
230 struct iovec iov[1];
231 ssize_t ret = -1;
232
233 iov[0].iov_base = buf;
234 iov[0].iov_len = len;
235 msg.msg_iov = iov;
236 msg.msg_iovlen = 1;
237
238 ret = recvmsg(sock, &msg, 0);
239 if (ret < 0) {
240 perror("recvmsg");
241 }
242
243 return ret;
244 }
245
246 /*
247 * lttcomm_send_unix_sock
248 *
249 * Send buf data of size len. Using sendmsg API.
250 * Return the size of sent data.
251 */
252 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
253 {
254 struct msghdr msg = { 0 };
255 struct iovec iov[1];
256 ssize_t ret = -1;
257
258 iov[0].iov_base = buf;
259 iov[0].iov_len = len;
260 msg.msg_iov = iov;
261 msg.msg_iovlen = 1;
262
263 ret = sendmsg(sock, &msg, 0);
264 if (ret < 0) {
265 perror("sendmsg");
266 }
267
268 return ret;
269 }
270
271 /*
272 * lttcomm_close_unix_sock
273 *
274 * Shutdown cleanly a unix socket.
275 */
276 int lttcomm_close_unix_sock(int sock)
277 {
278 int ret;
279
280 /* Shutdown receptions and transmissions */
281 ret = shutdown(sock, SHUT_RDWR);
282 if (ret < 0) {
283 perror("shutdown");
284 }
285
286 return ret;
287 }
288
289 /*
290 * lttcomm_send_fds_unix_sock
291 *
292 * Send multiple fds on a unix socket.
293 */
294 ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
295 {
296 struct msghdr msg = { 0 };
297 struct cmsghdr *cmptr;
298 struct iovec iov[1];
299 ssize_t ret = -1;
300 unsigned int sizeof_fds = nb_fd * sizeof(int);
301 char tmp[CMSG_SPACE(sizeof_fds)];
302
303 /*
304 * Note: the consumerd receiver only supports receiving one FD per
305 * message.
306 */
307 assert(nb_fd == 1);
308
309 msg.msg_control = (caddr_t)tmp;
310 msg.msg_controllen = CMSG_LEN(sizeof_fds);
311
312 cmptr = CMSG_FIRSTHDR(&msg);
313 cmptr->cmsg_level = SOL_SOCKET;
314 cmptr->cmsg_type = SCM_RIGHTS;
315 cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
316 memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
317 /* Sum of the length of all control messages in the buffer: */
318 msg.msg_controllen = cmptr->cmsg_len;
319
320 iov[0].iov_base = buf;
321 iov[0].iov_len = len;
322 msg.msg_iov = iov;
323 msg.msg_iovlen = 1;
324
325 ret = sendmsg(sock, &msg, 0);
326 if (ret < 0) {
327 perror("sendmsg");
328 }
329
330 return ret;
331 }
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