7337d92cade22a4b143ad57932390cd5ad779cea
[lttng-tools.git] / lttng / conf.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 as published by
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 along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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/stat.h>
25 #include <sys/types.h>
26 #include <unistd.h>
27
28 #include "conf.h"
29 #include "lttngerr.h"
30
31 /*
32 * config_get_file_path
33 *
34 * Return the path with '/CONFIG_FILENAME' added to it.
35 */
36 char *config_get_file_path(char *path)
37 {
38 int ret;
39 char *file_path;
40
41 ret = asprintf(&file_path, "%s/%s", path, CONFIG_FILENAME);
42 if (ret < 0) {
43 ERR("Fail allocating config file path");
44 }
45
46 return file_path;
47 }
48
49 /*
50 * open_config
51 *
52 * Return an open FILE pointer to the config file.
53 */
54 static FILE *open_config(char *path, const char *mode)
55 {
56 FILE *fp = NULL;
57 char *file_path;
58
59 file_path = config_get_file_path(path);
60 if (file_path == NULL) {
61 goto error;
62 }
63
64 fp = fopen(file_path, mode);
65 if (fp == NULL) {
66 goto error;
67 }
68
69 error:
70 if (file_path) {
71 free(file_path);
72 }
73 return fp;
74 }
75
76 /*
77 * create_config_file
78 *
79 * Create the empty config file a the path.
80 */
81 static int create_config_file(char *path)
82 {
83 int ret;
84 FILE *fp;
85
86 fp = open_config(path, "w+");
87 if (fp == NULL) {
88 ERR("Unable to create config file");
89 ret = -1;
90 goto error;
91 }
92
93 ret = fclose(fp);
94
95 error:
96 return ret;
97 }
98
99 /*
100 * write_config
101 *
102 * Append data to the config file in file_path
103 */
104 static int write_config(char *file_path, size_t size, char *data)
105 {
106 FILE *fp;
107 size_t len;
108 int ret = 0;
109
110 fp = open_config(file_path, "a");
111 if (fp == NULL) {
112 ret = -1;
113 goto end;
114 }
115
116 /* Write session name into config file */
117 len = fwrite(data, size, 1, fp);
118 if (len < 1) {
119 ret = -1;
120 }
121 fclose(fp);
122 end:
123 return ret;
124 }
125
126 /*
127 * config_get_default_path
128 *
129 * Return the HOME directory path. Caller MUST NOT free(3) the return pointer.
130 */
131 char *config_get_default_path(void)
132 {
133 return getenv("HOME");
134 }
135
136 /*
137 * config_destroy
138 *
139 * Destroy directory config and file config.
140 */
141 void config_destroy(char *path)
142 {
143 int ret;
144 char *config_path;
145
146 config_path = config_get_file_path(path);
147 if (config_path == NULL) {
148 return;
149 }
150
151 ret = remove(config_path);
152 if (ret < 0) {
153 perror("remove config file");
154 }
155
156 free(config_path);
157 }
158
159 /*
160 * config_read_session_name
161 *
162 * Return sesson name from the config file.
163 */
164 char *config_read_session_name(char *path)
165 {
166 int ret;
167 FILE *fp;
168 char var[NAME_MAX], *session_name;
169
170 fp = open_config(path, "r");
171 if (fp == NULL) {
172 ERR("Can't find valid lttng config %s/.lttngrc", path);
173 MSG("Did you create a session? (lttng create <my_sesion>)");
174 goto error;
175 }
176
177 session_name = malloc(NAME_MAX);
178 while (!feof(fp)) {
179 if ((ret = fscanf(fp, "%[^'=']=%s\n", var, session_name)) != 2) {
180 if (ret == -1) {
181 ERR("Missing session=NAME in config file.");
182 goto error;
183 }
184 continue;
185 }
186
187 if (strcmp(var, "session") == 0) {
188 goto found;
189 }
190 }
191
192 fclose(fp);
193
194 error:
195 return NULL;
196
197 found:
198 fclose(fp);
199 return session_name;
200
201 }
202
203 /*
204 * config_add_session_name
205 *
206 * Write session name option to the config file.
207 */
208 int config_add_session_name(char *path, char *name)
209 {
210 int ret;
211 char session_name[NAME_MAX];
212
213 ret = snprintf(session_name, NAME_MAX, "session=%s\n", name);
214 if (ret < 0) {
215 goto error;
216 }
217 ret = write_config(path, ret, session_name);
218 error:
219 return ret;
220 }
221
222 /*
223 * config_init
224 *
225 * Init configuration directory and file.
226 */
227 int config_init(char *session_name)
228 {
229 int ret;
230 char *path;
231
232 path = config_get_default_path();
233 if (path == NULL) {
234 ret = -1;
235 goto error;
236 }
237
238 /* Create default config file */
239 ret = create_config_file(path);
240 if (ret < 0) {
241 goto error;
242 }
243
244 ret = config_add_session_name(path, session_name);
245 if (ret < 0) {
246 goto error;
247 }
248
249 DBG("Init config session in %s", path);
250
251 error:
252 return ret;
253 }
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