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  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   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  *  get_config_file_path
  33  *
  34  *  Return the path with '/CONFIG_FILENAME' added to it.
  35  */
  36 static char *get_config_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 = get_config_file_path(path);
  60         if (file_path == NULL) {
  61                 goto error;
  62         }
  63
  64         fp = fopen(file_path, mode);
  65         if (fp == NULL) {
  66                 perror("config file");
  67                 goto error;
  68         }
  69
  70 error:
  71         if (file_path) {
  72                 free(file_path);
  73         }
  74         return fp;
  75 }
  76
  77 /*
  78  *  create_config_file
  79  *
  80  *  Create the empty config file a the path.
  81  */
  82 static int create_config_file(char *path)
  83 {
  84         int ret;
  85         FILE *fp;
  86
  87         fp = open_config(path, "w+");
  88         if (fp == NULL) {
  89                 ERR("Unable to create config file");
  90                 ret = -1;
  91                 goto error;
  92         }
  93
  94         ret = fclose(fp);
  95
  96 error:
  97         return ret;
  98 }
  99
 100 /*
 101  *  create_config_dir
 102  *
 103  *  Create the empty config dir.
 104  */
 105 static int create_config_dir(char *path)
 106 {
 107         int ret;
 108
 109         /* Create session directory .lttng */
 110         ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP);
 111         if (ret < 0) {
 112                 if (errno != EEXIST) {
 113                         perror("mkdir config");
 114                         ERR("Couldn't init config directory at %s", path);
 115                         ret = -errno;
 116                         goto error;
 117                 } else {
 118                         ret = 0;
 119                 }
 120         }
 121
 122 error:
 123         return ret;
 124 }
 125
 126 /*
 127  *  write_config
 128  *
 129  *  Append data to the config file in file_path
 130  */
 131 static void write_config(char *file_path, size_t size, char *data)
 132 {
 133         FILE *fp;
 134
 135         fp = open_config(file_path, "a");
 136         if (fp == NULL) {
 137                 goto error;
 138         }
 139
 140         /* Write session name into config file */
 141         fwrite(data, size, 1, fp);
 142         fclose(fp);
 143
 144 error:
 145         return;
 146 }
 147
 148 /*
 149  *  config_get_default_path
 150  *
 151  *  Return the HOME directory path. The output is dup so the user MUST
 152  *  free(3) the returned string.
 153  */
 154 char *config_get_default_path(void)
 155 {
 156         return strdup(getenv("HOME"));
 157 }
 158
 159 /*
 160  *  config_destroy
 161  *
 162  *  Destroy directory config and file config.
 163  */
 164 void config_destroy(char *path)
 165 {
 166         int ret;
 167         char *config_path;
 168
 169         config_path = get_config_file_path(path);
 170
 171         ret = remove(config_path);
 172         if (ret < 0) {
 173                 perror("remove config file");
 174         }
 175
 176         free(config_path);
 177 }
 178
 179 /*
 180  *  config_read_session_name
 181  *
 182  *  Return sesson name from the config file.
 183  */
 184 char *config_read_session_name(char *path)
 185 {
 186         int ret;
 187         FILE *fp;
 188         char var[NAME_MAX], *session_name;
 189
 190         fp = open_config(path, "r");
 191         if (fp == NULL) {
 192                 ERR("Can't find valid lttng config in %s", path);
 193                 goto error;
 194         }
 195
 196         session_name = malloc(NAME_MAX);
 197         while (!feof(fp)) {
 198                 if ((ret = fscanf(fp, "%[^'=']=%s\n", var, session_name)) != 2) {
 199                         if (ret == -1) {
 200                                 ERR("Missing session=NAME in config file.");
 201                                 goto error;
 202                         }
 203                         continue;
 204                 }
 205
 206                 if (strcmp(var, "session") == 0) {
 207                         goto found;
 208                 }
 209         }
 210
 211         fclose(fp);
 212
 213 error:
 214         return NULL;
 215
 216 found:
 217         fclose(fp);
 218         return session_name;
 219
 220 }
 221
 222 /*
 223  *  config_add_session_name
 224  *
 225  *  Write session name option to the config file.
 226  */
 227 int config_add_session_name(char *path, char *name)
 228 {
 229         int ret;
 230         char session_name[NAME_MAX];
 231
 232         ret = snprintf(session_name, NAME_MAX, "session=%s\n", name);
 233         if (ret < 0) {
 234                 goto error;
 235         }
 236
 237         write_config(path, ret, session_name);
 238         ret = 0;
 239
 240 error:
 241         return ret;
 242 }
 243
 244 /*
 245  *  config_generate_dir_path
 246  *
 247  *  Return allocated path string to path/CONFIG_DIRNAME.
 248  */
 249 char *config_generate_dir_path(char *path)
 250 {
 251         int ret;
 252         char *new_path;
 253
 254         ret = asprintf(&new_path, "%s/%s", path, CONFIG_DIRNAME);
 255         if (ret < 0) {
 256                 perror("config path problem");
 257                 goto error;
 258         }
 259
 260 error:
 261         return new_path;
 262 }
 263
 264 /*
 265  *  config_init
 266  *
 267  *  Init configuration directory and file.
 268  */
 269 int config_init(char *path)
 270 {
 271         int ret;
 272
 273         /* Create config directory (.lttng) */
 274         ret = create_config_dir(path);
 275         if (ret < 0) {
 276                 goto error;
 277         }
 278
 279         /* Create default config file */
 280         ret = create_config_file(path);
 281         if (ret < 0) {
 282                 goto error;
 283         }
 284
 285         DBG("Init config session in %s", path);
 286
 287 error:
 288         return ret;
 289 }