conf.c

   1 /* -*- Mode: C ; c-basic-offset: 2 -*- */
   2 /*
   3  * ALSA SEQ < - > JACK MIDI bridge
   4  *
   5  * Copyright (c) 2008,2009 Nedko Arnaudov <nedko@arnaudov.name>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; version 2 of the License.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  */
  20
  21 #include <sys/stat.h>
  22 #include <stdbool.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <time.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <expat.h>
  29
  30 #include "conf.h"
  31 #include "log.h"
  32 #include "paths.h"
  33
  34 #define A2J_CONF_HEADER_TEXT                            \
  35   "a2jmidid settings.\n"                                \
  36   "You probably don't want to edit this because\n"      \
  37   "it will be overwritten next time a2jmidid saves.\n"
  38
  39 bool
  40 a2j_settings_write_string(int fd, const char * string)
  41 {
  42   size_t len;
  43
  44   len = strlen(string);
  45
  46   if (write(fd, string, len) != len)
  47   {
  48     a2j_error("write() failed to write config file.");
  49     return false;
  50   }
  51
  52   return true;
  53 }
  54
  55 bool
  56 a2j_settings_write_option(
  57   int fd,
  58   const char * name,
  59   const char * content)
  60 {
  61   if (!a2j_settings_write_string(fd, "  "))
  62   {
  63     return false;
  64   }
  65
  66   if (!a2j_settings_write_string(fd, "<option name=\""))
  67   {
  68     return false;
  69   }
  70
  71   if (!a2j_settings_write_string(fd, name))
  72   {
  73     return false;
  74   }
  75
  76   if (!a2j_settings_write_string(fd, "\">"))
  77   {
  78     return false;
  79   }
  80
  81   if (!a2j_settings_write_string(fd, content))
  82   {
  83     return false;
  84   }
  85
  86   if (!a2j_settings_write_string(fd, "</option>\n"))
  87   {
  88     return false;
  89   }
  90
  91   return true;
  92 }
  93
  94 void
  95 a2j_conf_save()
  96 {
  97   int fd;
  98   bool ret;
  99   time_t timestamp;
 100   char timestamp_str[26];
 101
 102   time(&timestamp);
 103   ctime_r(&timestamp, timestamp_str);
 104   timestamp_str[24] = 0;
 105
 106   a2j_info("Saving settings to \"%s\" ...", g_a2j_conf_path);
 107
 108   fd = open(g_a2j_conf_path, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 109   if (fd == -1)
 110   {
 111     a2j_error("open() failed to open conf filename. error is %d (%s)", errno, strerror(errno));
 112     goto exit;
 113   }
 114
 115   if (!a2j_settings_write_string(fd, "<?xml version=\"1.0\"?>\n"))
 116   {
 117     goto exit_close;
 118   }
 119
 120   if (!a2j_settings_write_string(fd, "<!--\n"))
 121   {
 122     goto exit_close;
 123   }
 124
 125   if (!a2j_settings_write_string(fd, A2J_CONF_HEADER_TEXT))
 126   {
 127     goto exit_close;
 128   }
 129
 130   if (!a2j_settings_write_string(fd, "-->\n"))
 131   {
 132     goto exit_close;
 133   }
 134
 135   if (!a2j_settings_write_string(fd, "<!-- "))
 136   {
 137     goto exit_close;
 138   }
 139
 140   if (!a2j_settings_write_string(fd, timestamp_str))
 141   {
 142     goto exit_close;
 143   }
 144
 145   if (!a2j_settings_write_string(fd, " -->\n"))
 146   {
 147     goto exit_close;
 148   }
 149
 150   if (!a2j_settings_write_string(fd, "<a2jmidid>\n"))
 151   {
 152     goto exit_close;
 153   }
 154
 155   if (!a2j_settings_write_option(fd, "jack_server_name", g_a2j_jack_server_name))
 156   {
 157     goto exit_close;
 158   }
 159
 160   if (!a2j_settings_write_option(fd, "export_hw_ports", g_a2j_export_hw_ports ? "true" : "false"))
 161   {
 162     goto exit_close;
 163   }
 164
 165   if (!a2j_settings_write_string(fd, "</a2jmidid>\n"))
 166   {
 167     goto exit_close;
 168   }
 169
 170   ret = true;
 171
 172 exit_close:
 173   close(fd);
 174
 175 exit:
 176   return;
 177 }
 178
 179 #define PARSE_CONTEXT_ROOT     0
 180 #define PARSE_CONTEXT_A2J      1
 181 #define PARSE_CONTEXT_OPTION   2
 182
 183 #define MAX_STACK_DEPTH       10
 184 #define MAX_OPTION_LENGTH     100
 185
 186 struct parse_context
 187 {
 188   XML_Bool error;
 189   unsigned int element[MAX_STACK_DEPTH];
 190   signed int depth;
 191   char option[MAX_OPTION_LENGTH+1];
 192   int option_used;
 193   char * name;
 194 };
 195
 196 void
 197 a2j_conf_set_bool_option(
 198   const char * value_str,
 199   bool * value_ptr)
 200 {
 201   if (strcmp(value_str, "true") == 0)
 202   {
 203     *value_ptr = true;
 204   }
 205   else if (strcmp(value_str, "false") == 0)
 206   {
 207     *value_ptr = false;
 208   }
 209   else
 210   {
 211     a2j_error("ignoring unknown bool value \"%s\"", value_str);
 212   }
 213 }
 214
 215 void
 216 a2j_conf_set_string_option(
 217   const char * input,
 218   char ** value)
 219 {
 220   char * dup;
 221
 222   dup = strdup(input);
 223   if (dup == NULL)
 224   {
 225     a2j_error("Out of memory");
 226     return;
 227   }
 228
 229   *value = dup;
 230 }
 231
 232 void
 233 a2j_conf_set_option(
 234   const char * option_name,
 235   const char * option_value)
 236 {
 237   a2j_info("setting option \"%s\" to value \"%s\"", option_name, option_value);
 238
 239   if (strcmp(option_name, "jack_server_name") == 0)
 240   {
 241     a2j_conf_set_string_option(option_value, &g_a2j_jack_server_name);
 242   }
 243   else if (strcmp(option_name, "export_hw_ports") == 0)
 244   {
 245     a2j_conf_set_bool_option(option_value, &g_a2j_export_hw_ports);
 246   }
 247   else
 248   {
 249     a2j_error(
 250       "Unknown parameter \"%s\"",
 251       option_name);
 252     return;
 253   }
 254 }
 255
 256 #define context_ptr ((struct parse_context *)data)
 257
 258 void
 259 a2j_conf_settings_callback_chrdata(void *data, const XML_Char *s, int len)
 260 {
 261   if (context_ptr->error)
 262   {
 263     return;
 264   }
 265
 266   if (context_ptr->element[context_ptr->depth] == PARSE_CONTEXT_OPTION)
 267   {
 268     if (context_ptr->option_used + len >= MAX_OPTION_LENGTH)
 269     {
 270       a2j_error("xml parse max char data length reached");
 271       context_ptr->error = XML_TRUE;
 272       return;
 273     }
 274
 275     memcpy(context_ptr->option + context_ptr->option_used, s, len);
 276     context_ptr->option_used += len;
 277   }
 278 }
 279
 280 void
 281 a2j_conf_settings_callback_elstart(void *data, const char *el, const char **attr)
 282 {
 283   if (context_ptr->error)
 284   {
 285     return;
 286   }
 287
 288   if (context_ptr->depth + 1 >= MAX_STACK_DEPTH)
 289   {
 290     a2j_error("xml parse max stack depth reached");
 291     context_ptr->error = XML_TRUE;
 292     return;
 293   }
 294
 295   if (strcmp(el, "a2jmidid") == 0)
 296   {
 297     //a2j_info("<jack>");
 298     context_ptr->element[++context_ptr->depth] = PARSE_CONTEXT_A2J;
 299     return;
 300   }
 301
 302   if (strcmp(el, "option") == 0)
 303   {
 304     //a2j_info("<option>");
 305     if ((attr[0] == NULL || attr[2] != NULL) || strcmp(attr[0], "name") != 0)
 306     {
 307       a2j_error("<option> XML element must contain exactly one attribute, named \"name\"");
 308       context_ptr->error = XML_TRUE;
 309       return;
 310     }
 311
 312     context_ptr->name = strdup(attr[1]);
 313     if (context_ptr->name == NULL)
 314     {
 315       a2j_error("strdup() failed");
 316       context_ptr->error = XML_TRUE;
 317       return;
 318     }
 319
 320     context_ptr->element[++context_ptr->depth] = PARSE_CONTEXT_OPTION;
 321     context_ptr->option_used = 0;
 322     return;
 323   }
 324
 325   a2j_error("unknown element \"%s\"", el);
 326   context_ptr->error = XML_TRUE;
 327 }
 328
 329 void
 330 a2j_conf_settings_callback_elend(void *data, const char *el)
 331 {
 332   if (context_ptr->error)
 333   {
 334     return;
 335   }
 336
 337   //a2j_info("element end (depth = %d, element = %u)", context_ptr->depth, context_ptr->element[context_ptr->depth]);
 338
 339   if (context_ptr->element[context_ptr->depth] == PARSE_CONTEXT_OPTION)
 340   {
 341     context_ptr->option[context_ptr->option_used] = 0;
 342
 343     if (context_ptr->depth == 1 &&
 344         context_ptr->element[0] == PARSE_CONTEXT_A2J)
 345     {
 346       a2j_conf_set_option(context_ptr->name, context_ptr->option);
 347     }
 348   }
 349
 350   context_ptr->depth--;
 351
 352   if (context_ptr->name != NULL)
 353   {
 354     free(context_ptr->name);
 355     context_ptr->name = NULL;
 356   }
 357 }
 358
 359 #undef context_ptr
 360
 361 void
 362 a2j_conf_load()
 363 {
 364   XML_Parser parser;
 365   int bytes_read;
 366   void *buffer;
 367   struct stat st;
 368   int fd;
 369   enum XML_Status xmls;
 370   struct parse_context context;
 371
 372   a2j_info("Loading settings from \"%s\" using %s ...", g_a2j_conf_path, XML_ExpatVersion());
 373
 374   if (stat(g_a2j_conf_path, &st) != 0)
 375   {
 376     if (errno == ENOENT)
 377     {
 378       a2j_info("No conf file found, using defaults...");
 379       return;
 380     }
 381
 382     a2j_error("failed to stat \"%s\", error is %d (%s)", g_a2j_conf_path, errno, strerror(errno));
 383   }
 384
 385   fd = open(g_a2j_conf_path, O_RDONLY);
 386   if (fd == -1)
 387   {
 388     a2j_error("open() failed to open conf filename.");
 389     goto exit;
 390   }
 391
 392   parser = XML_ParserCreate(NULL);
 393   if (parser == NULL)
 394   {
 395     a2j_error("XML_ParserCreate() failed to create parser object.");
 396     goto exit_close_file;
 397   }
 398
 399   //a2j_info("conf file size is %llu bytes", (unsigned long long)st.st_size);
 400
 401   /* we are expecting that conf file has small enough size to fit in memory */
 402
 403   buffer = XML_GetBuffer(parser, st.st_size);
 404   if (buffer == NULL)
 405   {
 406     a2j_error("XML_GetBuffer() failed.");
 407     goto exit_free_parser;
 408   }
 409
 410   bytes_read = read(fd, buffer, st.st_size);
 411   if (bytes_read != st.st_size)
 412   {
 413     a2j_error("read() returned unexpected result.");
 414     goto exit_free_parser;
 415   }
 416
 417   context.error = XML_FALSE;
 418   context.depth = -1;
 419   context.name = NULL;
 420
 421   XML_SetElementHandler(parser, a2j_conf_settings_callback_elstart, a2j_conf_settings_callback_elend);
 422   XML_SetCharacterDataHandler(parser, a2j_conf_settings_callback_chrdata);
 423   XML_SetUserData(parser, &context);
 424
 425   xmls = XML_ParseBuffer(parser, bytes_read, XML_TRUE);
 426   if (xmls == XML_STATUS_ERROR)
 427   {
 428     a2j_error("XML_ParseBuffer() failed.");
 429     goto exit_free_parser;
 430   }
 431
 432 exit_free_parser:
 433   XML_ParserFree(parser);
 434
 435 exit_close_file:
 436   close(fd);
 437
 438 exit:
 439   return;
 440 }