5ca92d8d14a87049a743f375c5efaa55bb82e3bc
[lttng-tools.git] / src / bin / lttng / commands / start.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 modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _GNU_SOURCE
19 #include <popt.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <sys/stat.h>
24 #include <sys/types.h>
25 #include <unistd.h>
26
27 #include <common/sessiond-comm/sessiond-comm.h>
28 #include <common/mi-lttng.h>
29
30 #include "../command.h"
31
32
33 static char *opt_session_name;
34 static struct mi_writer *writer;
35
36 enum {
37 OPT_HELP = 1,
38 OPT_LIST_OPTIONS,
39 };
40
41 static struct poptOption long_options[] = {
42 /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
43 {"help", 'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
44 {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
45 {0, 0, 0, 0, 0, 0, 0}
46 };
47
48 /*
49 * usage
50 */
51 static void usage(FILE *ofp)
52 {
53 fprintf(ofp, "usage: lttng start [NAME] [OPTIONS]\n");
54 fprintf(ofp, "\n");
55 fprintf(ofp, "Where NAME is an optional session name. If not specified, lttng will\n");
56 fprintf(ofp, "get it from the configuration directory (.lttng).\n");
57 fprintf(ofp, "\n");
58 fprintf(ofp, "Options:\n");
59 fprintf(ofp, " -h, --help Show this help\n");
60 fprintf(ofp, " --list-options Simple listing of options\n");
61 fprintf(ofp, "\n");
62 }
63
64 static int mi_print_session(char *session_name, int enabled)
65 {
66 int ret;
67
68 /* Open session element */
69 ret = mi_lttng_writer_open_element(writer, config_element_session);
70 if (ret) {
71 goto end;
72 }
73
74 /* Print session name element */
75 ret = mi_lttng_writer_write_element_string(writer, config_element_name,
76 session_name);
77 if (ret) {
78 goto end;
79 }
80
81 ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
82 enabled);
83 if (ret) {
84 goto end;
85 }
86
87 /* Close session element */
88 ret = mi_lttng_writer_close_element(writer);
89
90 end:
91 return ret;
92 }
93
94 /*
95 * start_tracing
96 *
97 * Start tracing for all trace of the session.
98 */
99 static int start_tracing(void)
100 {
101 int ret;
102 char *session_name;
103
104 if (opt_session_name == NULL) {
105 session_name = get_session_name();
106 if (session_name == NULL) {
107 ret = CMD_ERROR;
108 goto error;
109 }
110 } else {
111 session_name = opt_session_name;
112 }
113
114 DBG("Starting tracing for session %s", session_name);
115
116 ret = lttng_start_tracing(session_name);
117 if (ret < 0) {
118 switch (-ret) {
119 case LTTNG_ERR_TRACE_ALREADY_STARTED:
120 WARN("Tracing already started for session %s", session_name);
121 break;
122 default:
123 ERR("%s", lttng_strerror(ret));
124 break;
125 }
126 goto free_name;
127 }
128
129 ret = CMD_SUCCESS;
130
131 MSG("Tracing started for session %s", session_name);
132 if (lttng_opt_mi) {
133 ret = mi_print_session(session_name, 1);
134 if (ret) {
135 ret = CMD_ERROR;
136 goto free_name;
137 }
138 }
139
140 free_name:
141 if (opt_session_name == NULL) {
142 free(session_name);
143 }
144 error:
145 return ret;
146 }
147
148 /*
149 * cmd_start
150 *
151 * The 'start <options>' first level command
152 */
153 int cmd_start(int argc, const char **argv)
154 {
155 int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
156 static poptContext pc;
157
158 pc = poptGetContext(NULL, argc, argv, long_options, 0);
159 poptReadDefaultConfig(pc, 0);
160
161 while ((opt = poptGetNextOpt(pc)) != -1) {
162 switch (opt) {
163 case OPT_HELP:
164 usage(stdout);
165 goto end;
166 case OPT_LIST_OPTIONS:
167 list_cmd_options(stdout, long_options);
168 goto end;
169 default:
170 usage(stderr);
171 ret = CMD_UNDEFINED;
172 goto end;
173 }
174 }
175
176 opt_session_name = (char*) poptGetArg(pc);
177
178 /* Mi check */
179 if (lttng_opt_mi) {
180 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
181 if (!writer) {
182 ret = -LTTNG_ERR_NOMEM;
183 goto end;
184 }
185
186 /* Open command element */
187 ret = mi_lttng_writer_command_open(writer,
188 mi_lttng_element_command_start);
189 if (ret) {
190 ret = CMD_ERROR;
191 goto end;
192 }
193
194 /* Open output element */
195 ret = mi_lttng_writer_open_element(writer,
196 mi_lttng_element_command_output);
197 if (ret) {
198 ret = CMD_ERROR;
199 goto end;
200 }
201
202 /*
203 * Open sessions element
204 * For validation purpose
205 */
206 ret = mi_lttng_writer_open_element(writer,
207 config_element_sessions);
208 if (ret) {
209 ret = CMD_ERROR;
210 goto end;
211 }
212 }
213
214 command_ret = start_tracing();
215 if (command_ret) {
216 success = 0;
217 }
218
219 /* Mi closing */
220 if (lttng_opt_mi) {
221 /* Close sessions and output element */
222 ret = mi_lttng_close_multi_element(writer, 2);
223 if (ret) {
224 ret = CMD_ERROR;
225 goto end;
226 }
227
228 /* Success ? */
229 ret = mi_lttng_writer_write_element_bool(writer,
230 mi_lttng_element_command_success, success);
231 if (ret) {
232 ret = CMD_ERROR;
233 goto end;
234 }
235
236 /* Command element close */
237 ret = mi_lttng_writer_command_close(writer);
238 if (ret) {
239 ret = CMD_ERROR;
240 goto end;
241 }
242 }
243
244 end:
245 /* Mi clean-up */
246 if (writer && mi_lttng_writer_destroy(writer)) {
247 /* Preserve original error code */
248 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
249 }
250
251 /* Overwrite ret if an error occurred with start_tracing */
252 ret = command_ret ? command_ret : ret;
253 poptFreeContext(pc);
254 return ret;
255 }
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