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 static int parse_option_bool(const char *name, const char *value, int *ret)
 169 {
 170     if (value != NULL) {
 171         if (!strcmp(value, "on")) {
 172             *ret = 1;
 173         } else if (!strcmp(value, "off")) {
 174             *ret = 0;
 175         } else {
 176             fprintf(stderr, "Option '%s': Use 'on' or 'off'\n", name);
 177             return -1;
 178         }
 179     } else {
 180         *ret = 1;
 181     }
 182     return 0;
 183 }
 184
 185 /*
 186  * Sets the value of a parameter in a given option list. The parsing of the
 187  * value depends on the type of option:
 188  *
 189  * OPT_FLAG (uses value.n):
 190  *      If no value is given, the flag is set to 1.
 191  *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
 192  *
 193  * OPT_STRING (uses value.s):
 194  *      value is strdup()ed and assigned as option value
 195  *
 196  * OPT_SIZE (uses value.n):
 197  *      The value is converted to an integer. Suffixes for kilobytes etc. are
 198  *      allowed (powers of 1024).
 199  *
 200  * Returns 0 on succes, -1 in error cases
 201  */
 202 int set_option_parameter(QEMUOptionParameter *list, const char *name,
 203     const char *value)
 204 {
 205     int flag;
 206
 207     // Find a matching parameter
 208     list = get_option_parameter(list, name);
 209     if (list == NULL) {
 210         fprintf(stderr, "Unknown option '%s'\n", name);
 211         return -1;
 212     }
 213
 214     // Process parameter
 215     switch (list->type) {
 216     case OPT_FLAG:
 217         if (-1 == parse_option_bool(name, value, &flag))
 218             return -1;
 219         list->value.n = flag;
 220         break;
 221
 222     case OPT_STRING:
 223         if (value != NULL) {
 224             list->value.s = strdup(value);
 225         } else {
 226             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 227             return -1;
 228         }
 229         break;
 230
 231     case OPT_SIZE:
 232         if (value != NULL) {
 233             double sizef = strtod(value, (char**) &value);
 234
 235             switch (*value) {
 236             case 'T':
 237                 sizef *= 1024;
 238             case 'G':
 239                 sizef *= 1024;
 240             case 'M':
 241                 sizef *= 1024;
 242             case 'K':
 243             case 'k':
 244                 sizef *= 1024;
 245             case 'b':
 246             case '\0':
 247                 list->value.n = (uint64_t) sizef;
 248                 break;
 249             default:
 250                 fprintf(stderr, "Option '%s' needs size as parameter\n", name);
 251                 fprintf(stderr, "You may use k, M, G or T suffixes for "
 252                     "kilobytes, megabytes, gigabytes and terabytes.\n");
 253                 return -1;
 254             }
 255         } else {
 256             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 257             return -1;
 258         }
 259         break;
 260     default:
 261         fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
 262         return -1;
 263     }
 264
 265     return 0;
 266 }
 267
 268 /*
 269  * Sets the given parameter to an integer instead of a string.
 270  * This function cannot be used to set string options.
 271  *
 272  * Returns 0 on success, -1 in error cases
 273  */
 274 int set_option_parameter_int(QEMUOptionParameter *list, const char *name,
 275     uint64_t value)
 276 {
 277     // Find a matching parameter
 278     list = get_option_parameter(list, name);
 279     if (list == NULL) {
 280         fprintf(stderr, "Unknown option '%s'\n", name);
 281         return -1;
 282     }
 283
 284     // Process parameter
 285     switch (list->type) {
 286     case OPT_FLAG:
 287     case OPT_NUMBER:
 288     case OPT_SIZE:
 289         list->value.n = value;
 290         break;
 291
 292     default:
 293         return -1;
 294     }
 295
 296     return 0;
 297 }
 298
 299 /*
 300  * Frees a option list. If it contains strings, the strings are freed as well.
 301  */
 302 void free_option_parameters(QEMUOptionParameter *list)
 303 {
 304     QEMUOptionParameter *cur = list;
 305
 306     while (cur && cur->name) {
 307         if (cur->type == OPT_STRING) {
 308             free(cur->value.s);
 309         }
 310         cur++;
 311     }
 312
 313     free(list);
 314 }
 315
 316 /*
 317  * Parses a parameter string (param) into an option list (dest).
 318  *
 319  * list is the templace is. If dest is NULL, a new copy of list is created for
 320  * it. If list is NULL, this function fails.
 321  *
 322  * A parameter string consists of one or more parameters, separated by commas.
 323  * Each parameter consists of its name and possibly of a value. In the latter
 324  * case, the value is delimited by an = character. To specify a value which
 325  * contains commas, double each comma so it won't be recognized as the end of
 326  * the parameter.
 327  *
 328  * For more details of the parsing see above.
 329  *
 330  * Returns a pointer to the first element of dest (or the newly allocated copy)
 331  * or NULL in error cases
 332  */
 333 QEMUOptionParameter *parse_option_parameters(const char *param,
 334     QEMUOptionParameter *list, QEMUOptionParameter *dest)
 335 {
 336     QEMUOptionParameter *cur;
 337     QEMUOptionParameter *allocated = NULL;
 338     char name[256];
 339     char value[256];
 340     char *param_delim, *value_delim;
 341     char next_delim;
 342     size_t num_options;
 343
 344     if (list == NULL) {
 345         return NULL;
 346     }
 347
 348     if (dest == NULL) {
 349         // Count valid options
 350         num_options = 0;
 351         cur = list;
 352         while (cur->name) {
 353             num_options++;
 354             cur++;
 355         }
 356
 357         // Create a copy of the option list to fill in values
 358         dest = qemu_mallocz((num_options + 1) * sizeof(QEMUOptionParameter));
 359         allocated = dest;
 360         memcpy(dest, list, (num_options + 1) * sizeof(QEMUOptionParameter));
 361     }
 362
 363     while (*param) {
 364
 365         // Find parameter name and value in the string
 366         param_delim = strchr(param, ',');
 367         value_delim = strchr(param, '=');
 368
 369         if (value_delim && (value_delim < param_delim || !param_delim)) {
 370             next_delim = '=';
 371         } else {
 372             next_delim = ',';
 373             value_delim = NULL;
 374         }
 375
 376         param = get_opt_name(name, sizeof(name), param, next_delim);
 377         if (value_delim) {
 378             param = get_opt_value(value, sizeof(value), param + 1);
 379         }
 380         if (*param != '\0') {
 381             param++;
 382         }
 383
 384         // Set the parameter
 385         if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
 386             goto fail;
 387         }
 388     }
 389
 390     return dest;
 391
 392 fail:
 393     // Only free the list if it was newly allocated
 394     free_option_parameters(allocated);
 395     return NULL;
 396 }
 397
 398 /*
 399  * Prints all options of a list that have a value to stdout
 400  */
 401 void print_option_parameters(QEMUOptionParameter *list)
 402 {
 403     while (list && list->name) {
 404         switch (list->type) {
 405             case OPT_STRING:
 406                  if (list->value.s != NULL) {
 407                      printf("%s='%s' ", list->name, list->value.s);
 408                  }
 409                 break;
 410             case OPT_FLAG:
 411                 printf("%s=%s ", list->name, list->value.n ? "on" : "off");
 412                 break;
 413             case OPT_SIZE:
 414             case OPT_NUMBER:
 415                 printf("%s=%" PRId64 " ", list->name, list->value.n);
 416                 break;
 417             default:
 418                 printf("%s=(unkown type) ", list->name);
 419                 break;
 420         }
 421         list++;
 422     }
 423 }
 424
 425 /*
 426  * Prints an overview of all available options
 427  */
 428 void print_option_help(QEMUOptionParameter *list)
 429 {
 430     printf("Supported options:\n");
 431     while (list && list->name) {
 432         printf("%-16s %s\n", list->name,
 433             list->help ? list->help : "No description available");
 434         list++;
 435     }
 436 }