Refactoring: use an opaque lttng_tracker_id type
[lttng-tools.git] / src / bin / lttng / conf.c
CommitLineData
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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
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AM
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
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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
6c1c0768 18#define _LGPL_SOURCE
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19#include <limits.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>
1dac0189 26#include <errno.h>
f3ed775e 27
9908810a 28#include <common/common.h>
feb0f3e5 29#include <common/utils.h>
10a8a223 30
beb8c75a 31#include "conf.h"
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32
33/*
28eee19b
FG
34 * Returns the path with '/CONFIG_FILENAME' added to it;
35 * path will be NULL if an error occurs.
f3ed775e 36 */
9b27c721 37char *config_get_file_path(const char *path)
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38{
39 int ret;
40 char *file_path;
41
42 ret = asprintf(&file_path, "%s/%s", path, CONFIG_FILENAME);
43 if (ret < 0) {
44 ERR("Fail allocating config file path");
487b253b 45 file_path = NULL;
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46 }
47
48 return file_path;
49}
50
51/*
28eee19b
FG
52 * Returns an open FILE pointer to the config file;
53 * on error, NULL is returned.
f3ed775e 54 */
9b27c721 55static FILE *open_config(const char *path, const char *mode)
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56{
57 FILE *fp = NULL;
58 char *file_path;
59
58a97671 60 file_path = config_get_file_path(path);
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61 if (file_path == NULL) {
62 goto error;
63 }
64
65 fp = fopen(file_path, mode);
66 if (fp == NULL) {
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67 goto error;
68 }
69
70error:
0e428499 71 free(file_path);
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72 return fp;
73}
74
75/*
28eee19b
FG
76 * Creates the empty config file at the path.
77 * On success, returns 0;
78 * on error, returns -1.
f3ed775e 79 */
4f00620d 80static int create_config_file(const char *path)
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81{
82 int ret;
83 FILE *fp;
84
85 fp = open_config(path, "w+");
86 if (fp == NULL) {
87 ERR("Unable to create config file");
88 ret = -1;
89 goto error;
90 }
91
92 ret = fclose(fp);
93
94error:
95 return ret;
96}
97
f3ed775e 98/*
28eee19b
FG
99 * Append data to the config file in file_path
100 * On success, returns 0;
101 * on error, returns -1.
f3ed775e 102 */
9b27c721 103static int write_config(const char *file_path, size_t size, char *data)
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104{
105 FILE *fp;
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106 size_t len;
107 int ret = 0;
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108
109 fp = open_config(file_path, "a");
110 if (fp == NULL) {
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111 ret = -1;
112 goto end;
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113 }
114
115 /* Write session name into config file */
a079cd4d 116 len = fwrite(data, size, 1, fp);
27089920 117 if (len != 1) {
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118 ret = -1;
119 }
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120 if (fclose(fp)) {
121 PERROR("close write_config");
122 }
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123end:
124 return ret;
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125}
126
f3ed775e 127/*
28eee19b 128 * Destroys directory config and file config.
f3ed775e 129 */
9b27c721 130void config_destroy(const char *path)
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131{
132 int ret;
133 char *config_path;
134
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135 config_path = config_get_file_path(path);
136 if (config_path == NULL) {
137 return;
138 }
f3ed775e 139
d6a07e7d
FG
140 if (!config_exists(config_path)) {
141 goto end;
142 }
143
144 DBG("Removing %s\n", config_path);
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145 ret = remove(config_path);
146 if (ret < 0) {
6f04ed72 147 PERROR("remove config file");
f3ed775e 148 }
d6a07e7d 149end:
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150 free(config_path);
151}
152
d6a07e7d 153/*
28eee19b 154 * Destroys the default config
d6a07e7d 155 */
d6a07e7d
FG
156void config_destroy_default(void)
157{
4f00620d 158 const char *path = utils_get_home_dir();
d6a07e7d
FG
159 if (path == NULL) {
160 return;
161 }
162 config_destroy(path);
163}
164
165/*
28eee19b 166 * Returns 1 if config exists, 0 otherwise
d6a07e7d
FG
167 */
168int config_exists(const char *path)
169{
170 int ret;
171 struct stat info;
172
173 ret = stat(path, &info);
174 if (ret < 0) {
175 return 0;
176 }
177 return S_ISREG(info.st_mode) || S_ISDIR(info.st_mode);
178}
179
1dac0189 180static
9b27c721 181int _config_read_session_name(const char *path, char **name)
f3ed775e 182{
1dac0189 183 int ret = 0;
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184 FILE *fp;
185 char var[NAME_MAX], *session_name;
09b72f7a 186
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187#if (NAME_MAX == 255)
188#define NAME_MAX_SCANF_IS_A_BROKEN_API "254"
189#endif
f3ed775e 190
9908810a 191 session_name = zmalloc(NAME_MAX);
27089920 192 if (session_name == NULL) {
1dac0189 193 ret = -ENOMEM;
27089920
TD
194 ERR("Out of memory");
195 goto error;
196 }
197
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198 fp = open_config(path, "r");
199 if (fp == NULL) {
1dac0189 200 ret = -ENOENT;
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201 goto error;
202 }
203
f3ed775e 204 while (!feof(fp)) {
8ab7c0d9
MD
205 if ((ret = fscanf(fp, "%" NAME_MAX_SCANF_IS_A_BROKEN_API
206 "[^'=']=%" NAME_MAX_SCANF_IS_A_BROKEN_API "s\n",
207 var, session_name)) != 2) {
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208 if (ret == -1) {
209 ERR("Missing session=NAME in config file.");
00f36863 210 goto error_close;
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211 }
212 continue;
213 }
214
215 if (strcmp(var, "session") == 0) {
216 goto found;
217 }
218 }
219
00f36863 220error_close:
1dac0189 221 if (fclose(fp) < 0) {
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222 PERROR("close config read session name");
223 }
f3ed775e 224error:
1dac0189
PPM
225 free(session_name);
226 return ret;
f3ed775e 227found:
1dac0189
PPM
228 *name = session_name;
229 if (fclose(fp) < 0) {
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230 PERROR("close config read session name found");
231 }
1dac0189
PPM
232 return ret;
233}
234
235/*
236 * Returns the session name from the config file.
237 *
238 * The caller is responsible for freeing the returned string.
239 * On error, NULL is returned.
240 */
9b27c721 241char *config_read_session_name(const char *path)
1dac0189
PPM
242{
243 int ret;
244 char *name = NULL;
245
246 ret = _config_read_session_name(path, &name);
247 if (ret == -ENOENT) {
248 const char *home_dir = utils_get_home_dir();
249
250 ERR("Can't find valid lttng config %s/.lttngrc", home_dir);
251 MSG("Did you create a session? (lttng create <my_session>)");
252 }
253
254 return name;
255}
256
257/*
258 * Returns the session name from the config file. (no warnings/errors emitted)
259 *
260 * The caller is responsible for freeing the returned string.
261 * On error, NULL is returned.
262 */
9b27c721 263char *config_read_session_name_quiet(const char *path)
1dac0189
PPM
264{
265 char *name = NULL;
f3ed775e 266
1dac0189
PPM
267 (void) _config_read_session_name(path, &name);
268 return name;
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269}
270
271/*
28eee19b
FG
272 * Write session name option to the config file.
273 * On success, returns 0;
274 * on error, returns -1.
f3ed775e 275 */
9b27c721 276int config_add_session_name(const char *path, const char *name)
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277{
278 int ret;
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279 char *attr = "session=";
280 /* Max name len accepted plus attribute's len and the NULL byte. */
281 char session_name[NAME_MAX + strlen(attr) + 1];
f3ed775e 282
27089920
TD
283 /*
284 * With GNU C < 2.1, snprintf returns -1 if the target buffer is too small;
285 * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
286 */
487b253b
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287 ret = snprintf(session_name, sizeof(session_name), "%s%s\n", attr, name);
288 if (ret < 0) {
27089920 289 ret = -1;
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290 goto error;
291 }
a079cd4d 292 ret = write_config(path, ret, session_name);
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293error:
294 return ret;
295}
296
f3ed775e 297/*
28eee19b
FG
298 * Init configuration directory and file.
299 * On success, returns 0;
300 * on error, returns -1.
f3ed775e 301 */
9b27c721 302int config_init(const char *session_name)
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303{
304 int ret;
4f00620d 305 const char *path;
f3ed775e 306
feb0f3e5 307 path = utils_get_home_dir();
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308 if (path == NULL) {
309 ret = -1;
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310 goto error;
311 }
312
313 /* Create default config file */
314 ret = create_config_file(path);
315 if (ret < 0) {
316 goto error;
317 }
318
58a97671
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319 ret = config_add_session_name(path, session_name);
320 if (ret < 0) {
321 goto error;
322 }
323
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324 DBG("Init config session in %s", path);
325
326error:
327 return ret;
328}
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