qemu-option.c

   1 /*
   2  * Commandline option parsing functions
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2009 Kevin Wolf <kwolf@redhat.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include "qemu-common.h"
  30 #include "qemu-option.h"
  31
  32 /*
  33  * Extracts the name of an option from the parameter string (p points at the
  34  * first byte of the option name)
  35  *
  36  * The option name is delimited by delim (usually , or =) or the string end
  37  * and is copied into buf. If the option name is longer than buf_size, it is
  38  * truncated. buf is always zero terminated.
  39  *
  40  * The return value is the position of the delimiter/zero byte after the option
  41  * name in p.
  42  */
  43 const char *get_opt_name(char *buf, int buf_size, const char *p, char delim)
  44 {
  45     char *q;
  46
  47     q = buf;
  48     while (*p != '\0' && *p != delim) {
  49         if (q && (q - buf) < buf_size - 1)
  50             *q++ = *p;
  51         p++;
  52     }
  53     if (q)
  54         *q = '\0';
  55
  56     return p;
  57 }
  58
  59 /*
  60  * Extracts the value of an option from the parameter string p (p points at the
  61  * first byte of the option value)
  62  *
  63  * This function is comparable to get_opt_name with the difference that the
  64  * delimiter is fixed to be comma which starts a new option. To specify an
  65  * option value that contains commas, double each comma.
  66  */
  67 const char *get_opt_value(char *buf, int buf_size, const char *p)
  68 {
  69     char *q;
  70
  71     q = buf;
  72     while (*p != '\0') {
  73         if (*p == ',') {
  74             if (*(p + 1) != ',')
  75                 break;
  76             p++;
  77         }
  78         if (q && (q - buf) < buf_size - 1)
  79             *q++ = *p;
  80         p++;
  81     }
  82     if (q)
  83         *q = '\0';
  84
  85     return p;
  86 }
  87
  88 int get_next_param_value(char *buf, int buf_size,
  89                          const char *tag, const char **pstr)
  90 {
  91     const char *p;
  92     char option[128];
  93
  94     p = *pstr;
  95     for(;;) {
  96         p = get_opt_name(option, sizeof(option), p, '=');
  97         if (*p != '=')
  98             break;
  99         p++;
 100         if (!strcmp(tag, option)) {
 101             *pstr = get_opt_value(buf, buf_size, p);
 102             if (**pstr == ',') {
 103                 (*pstr)++;
 104             }
 105             return strlen(buf);
 106         } else {
 107             p = get_opt_value(NULL, 0, p);
 108         }
 109         if (*p != ',')
 110             break;
 111         p++;
 112     }
 113     return 0;
 114 }
 115
 116 int get_param_value(char *buf, int buf_size,
 117                     const char *tag, const char *str)
 118 {
 119     return get_next_param_value(buf, buf_size, tag, &str);
 120 }
 121
 122 int check_params(char *buf, int buf_size,
 123                  const char * const *params, const char *str)
 124 {
 125     const char *p;
 126     int i;
 127
 128     p = str;
 129     while (*p != '\0') {
 130         p = get_opt_name(buf, buf_size, p, '=');
 131         if (*p != '=') {
 132             return -1;
 133         }
 134         p++;
 135         for (i = 0; params[i] != NULL; i++) {
 136             if (!strcmp(params[i], buf)) {
 137                 break;
 138             }
 139         }
 140         if (params[i] == NULL) {
 141             return -1;
 142         }
 143         p = get_opt_value(NULL, 0, p);
 144         if (*p != ',') {
 145             break;
 146         }
 147         p++;
 148     }
 149     return 0;
 150 }
 151
 152 /*
 153  * Searches an option list for an option with the given name
 154  */
 155 QEMUOptionParameter *get_option_parameter(QEMUOptionParameter *list,
 156     const char *name)
 157 {
 158     while (list && list->name) {
 159         if (!strcmp(list->name, name)) {
 160             return list;
 161         }
 162         list++;
 163     }
 164
 165     return NULL;
 166 }
 167
 168 /*
 169  * Sets the value of a parameter in a given option list. The parsing of the
 170  * value depends on the type of option:
 171  *
 172  * OPT_FLAG (uses value.n):
 173  *      If no value is given, the flag is set to 1.
 174  *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
 175  *
 176  * OPT_STRING (uses value.s):
 177  *      value is strdup()ed and assigned as option value
 178  *
 179  * OPT_SIZE (uses value.n):
 180  *      The value is converted to an integer. Suffixes for kilobytes etc. are
 181  *      allowed (powers of 1024).
 182  *
 183  * Returns 0 on succes, -1 in error cases
 184  */
 185 int set_option_parameter(QEMUOptionParameter *list, const char *name,
 186     const char *value)
 187 {
 188     // Find a matching parameter
 189     list = get_option_parameter(list, name);
 190     if (list == NULL) {
 191         fprintf(stderr, "Unknown option '%s'\n", name);
 192         return -1;
 193     }
 194
 195     // Process parameter
 196     switch (list->type) {
 197     case OPT_FLAG:
 198         if (value != NULL) {
 199             if (!strcmp(value, "on")) {
 200                 list->value.n = 1;
 201             } else if (!strcmp(value, "off")) {
 202                 list->value.n = 0;
 203             } else {
 204                 fprintf(stderr, "Option '%s': Use 'on' or 'off'\n", name);
 205                 return -1;
 206             }
 207         } else {
 208             list->value.n = 1;
 209         }
 210         break;
 211
 212     case OPT_STRING:
 213         if (value != NULL) {
 214             list->value.s = strdup(value);
 215         } else {
 216             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 217             return -1;
 218         }
 219         break;
 220
 221     case OPT_SIZE:
 222         if (value != NULL) {
 223             double sizef = strtod(value, (char**) &value);
 224
 225             switch (*value) {
 226             case 'T':
 227                 sizef *= 1024;
 228             case 'G':
 229                 sizef *= 1024;
 230             case 'M':
 231                 sizef *= 1024;
 232             case 'K':
 233             case 'k':
 234                 sizef *= 1024;
 235             case 'b':
 236             case '\0':
 237                 list->value.n = (uint64_t) sizef;
 238                 break;
 239             default:
 240                 fprintf(stderr, "Option '%s' needs size as parameter\n", name);
 241                 fprintf(stderr, "You may use k, M, G or T suffixes for "
 242                     "kilobytes, megabytes, gigabytes and terabytes.\n");
 243                 return -1;
 244             }
 245         } else {
 246             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 247             return -1;
 248         }
 249         break;
 250     default:
 251         fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
 252         return -1;
 253     }
 254
 255     return 0;
 256 }
 257
 258 /*
 259  * Sets the given parameter to an integer instead of a string.
 260  * This function cannot be used to set string options.
 261  *
 262  * Returns 0 on success, -1 in error cases
 263  */
 264 int set_option_parameter_int(QEMUOptionParameter *list, const char *name,
 265     uint64_t value)
 266 {
 267     // Find a matching parameter
 268     list = get_option_parameter(list, name);
 269     if (list == NULL) {
 270         fprintf(stderr, "Unknown option '%s'\n", name);
 271         return -1;
 272     }
 273
 274     // Process parameter
 275     switch (list->type) {
 276     case OPT_FLAG:
 277     case OPT_NUMBER:
 278     case OPT_SIZE:
 279         list->value.n = value;
 280         break;
 281
 282     default:
 283         return -1;
 284     }
 285
 286     return 0;
 287 }
 288
 289 /*
 290  * Frees a option list. If it contains strings, the strings are freed as well.
 291  */
 292 void free_option_parameters(QEMUOptionParameter *list)
 293 {
 294     QEMUOptionParameter *cur = list;
 295
 296     while (cur && cur->name) {
 297         if (cur->type == OPT_STRING) {
 298             free(cur->value.s);
 299         }
 300         cur++;
 301     }
 302
 303     free(list);
 304 }
 305
 306 /*
 307  * Parses a parameter string (param) into an option list (dest).
 308  *
 309  * list is the templace is. If dest is NULL, a new copy of list is created for
 310  * it. If list is NULL, this function fails.
 311  *
 312  * A parameter string consists of one or more parameters, separated by commas.
 313  * Each parameter consists of its name and possibly of a value. In the latter
 314  * case, the value is delimited by an = character. To specify a value which
 315  * contains commas, double each comma so it won't be recognized as the end of
 316  * the parameter.
 317  *
 318  * For more details of the parsing see above.
 319  *
 320  * Returns a pointer to the first element of dest (or the newly allocated copy)
 321  * or NULL in error cases
 322  */
 323 QEMUOptionParameter *parse_option_parameters(const char *param,
 324     QEMUOptionParameter *list, QEMUOptionParameter *dest)
 325 {
 326     QEMUOptionParameter *cur;
 327     QEMUOptionParameter *allocated = NULL;
 328     char name[256];
 329     char value[256];
 330     char *param_delim, *value_delim;
 331     char next_delim;
 332     size_t num_options;
 333
 334     if (list == NULL) {
 335         return NULL;
 336     }
 337
 338     if (dest == NULL) {
 339         // Count valid options
 340         num_options = 0;
 341         cur = list;
 342         while (cur->name) {
 343             num_options++;
 344             cur++;
 345         }
 346
 347         // Create a copy of the option list to fill in values
 348         dest = qemu_mallocz((num_options + 1) * sizeof(QEMUOptionParameter));
 349         allocated = dest;
 350         memcpy(dest, list, (num_options + 1) * sizeof(QEMUOptionParameter));
 351     }
 352
 353     while (*param) {
 354
 355         // Find parameter name and value in the string
 356         param_delim = strchr(param, ',');
 357         value_delim = strchr(param, '=');
 358
 359         if (value_delim && (value_delim < param_delim || !param_delim)) {
 360             next_delim = '=';
 361         } else {
 362             next_delim = ',';
 363             value_delim = NULL;
 364         }
 365
 366         param = get_opt_name(name, sizeof(name), param, next_delim);
 367         if (value_delim) {
 368             param = get_opt_value(value, sizeof(value), param + 1);
 369         }
 370         if (*param != '\0') {
 371             param++;
 372         }
 373
 374         // Set the parameter
 375         if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
 376             goto fail;
 377         }
 378     }
 379
 380     return dest;
 381
 382 fail:
 383     // Only free the list if it was newly allocated
 384     free_option_parameters(allocated);
 385     return NULL;
 386 }
 387
 388 /*
 389  * Prints all options of a list that have a value to stdout
 390  */
 391 void print_option_parameters(QEMUOptionParameter *list)
 392 {
 393     while (list && list->name) {
 394         switch (list->type) {
 395             case OPT_STRING:
 396                  if (list->value.s != NULL) {
 397                      printf("%s='%s' ", list->name, list->value.s);
 398                  }
 399                 break;
 400             case OPT_FLAG:
 401                 printf("%s=%s ", list->name, list->value.n ? "on" : "off");
 402                 break;
 403             case OPT_SIZE:
 404             case OPT_NUMBER:
 405                 printf("%s=%" PRId64 " ", list->name, list->value.n);
 406                 break;
 407             default:
 408                 printf("%s=(unkown type) ", list->name);
 409                 break;
 410         }
 411         list++;
 412     }
 413 }
 414
 415 /*
 416  * Prints an overview of all available options
 417  */
 418 void print_option_help(QEMUOptionParameter *list)
 419 {
 420     printf("Supported options:\n");
 421     while (list && list->name) {
 422         printf("%-16s %s\n", list->name,
 423             list->help ? list->help : "No description available");
 424         list++;
 425     }
 426 }