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 }