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 /*
  89  * Searches an option list for an option with the given name
  90  */
  91 QEMUOptionParameter *get_option_parameter(QEMUOptionParameter *list,
  92     const char *name)
  93 {
  94     while (list && list->name) {
  95         if (!strcmp(list->name, name)) {
  96             return list;
  97         }
  98         list++;
  99     }
 100
 101     return NULL;
 102 }
 103
 104 /*
 105  * Sets the value of a parameter in a given option list. The parsing of the
 106  * value depends on the type of option:
 107  *
 108  * OPT_FLAG (uses value.n):
 109  *      If no value is given, the flag is set to 1.
 110  *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
 111  *
 112  * OPT_STRING (uses value.s):
 113  *      value is strdup()ed and assigned as option value
 114  *
 115  * OPT_SIZE (uses value.n):
 116  *      The value is converted to an integer. Suffixes for kilobytes etc. are
 117  *      allowed (powers of 1024).
 118  *
 119  * Returns 0 on succes, -1 in error cases
 120  */
 121 int set_option_parameter(QEMUOptionParameter *list, const char *name,
 122     const char *value)
 123 {
 124     // Find a matching parameter
 125     list = get_option_parameter(list, name);
 126     if (list == NULL) {
 127         fprintf(stderr, "Unknown option '%s'\n", name);
 128         return -1;
 129     }
 130
 131     // Process parameter
 132     switch (list->type) {
 133     case OPT_FLAG:
 134         if (value != NULL) {
 135             if (!strcmp(value, "on")) {
 136                 list->value.n = 1;
 137             } else if (!strcmp(value, "off")) {
 138                 list->value.n = 0;
 139             } else {
 140                 fprintf(stderr, "Option '%s': Use 'on' or 'off'\n", name);
 141                 return -1;
 142             }
 143         } else {
 144             list->value.n = 1;
 145         }
 146         break;
 147
 148     case OPT_STRING:
 149         if (value != NULL) {
 150             list->value.s = strdup(value);
 151         } else {
 152             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 153             return -1;
 154         }
 155         break;
 156
 157     case OPT_SIZE:
 158         if (value != NULL) {
 159             double sizef = strtod(value, (char**) &value);
 160
 161             switch (*value) {
 162             case 'T':
 163                 sizef *= 1024;
 164             case 'G':
 165                 sizef *= 1024;
 166             case 'M':
 167                 sizef *= 1024;
 168             case 'K':
 169             case 'k':
 170                 sizef *= 1024;
 171             case 'b':
 172             case '\0':
 173                 list->value.n = (uint64_t) sizef;
 174                 break;
 175             default:
 176                 fprintf(stderr, "Option '%s' needs size as parameter\n", name);
 177                 fprintf(stderr, "You may use k, M, G or T suffixes for "
 178                     "kilobytes, megabytes, gigabytes and terabytes.\n");
 179                 return -1;
 180             }
 181         } else {
 182             fprintf(stderr, "Option '%s' needs a parameter\n", name);
 183             return -1;
 184         }
 185         break;
 186     default:
 187         fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
 188         return -1;
 189     }
 190
 191     return 0;
 192 }
 193
 194 /*
 195  * Sets the given parameter to an integer instead of a string.
 196  * This function cannot be used to set string options.
 197  *
 198  * Returns 0 on success, -1 in error cases
 199  */
 200 int set_option_parameter_int(QEMUOptionParameter *list, const char *name,
 201     uint64_t value)
 202 {
 203     // Find a matching parameter
 204     list = get_option_parameter(list, name);
 205     if (list == NULL) {
 206         fprintf(stderr, "Unknown option '%s'\n", name);
 207         return -1;
 208     }
 209
 210     // Process parameter
 211     switch (list->type) {
 212     case OPT_FLAG:
 213     case OPT_NUMBER:
 214     case OPT_SIZE:
 215         list->value.n = value;
 216         break;
 217
 218     default:
 219         return -1;
 220     }
 221
 222     return 0;
 223 }
 224
 225 /*
 226  * Frees a option list. If it contains strings, the strings are freed as well.
 227  */
 228 void free_option_parameters(QEMUOptionParameter *list)
 229 {
 230     QEMUOptionParameter *cur = list;
 231
 232     while (cur && cur->name) {
 233         if (cur->type == OPT_STRING) {
 234             free(cur->value.s);
 235         }
 236         cur++;
 237     }
 238
 239     free(list);
 240 }
 241
 242 /*
 243  * Parses a parameter string (param) into an option list (dest).
 244  *
 245  * list is the templace is. If dest is NULL, a new copy of list is created for
 246  * it. If list is NULL, this function fails.
 247  *
 248  * A parameter string consists of one or more parameters, separated by commas.
 249  * Each parameter consists of its name and possibly of a value. In the latter
 250  * case, the value is delimited by an = character. To specify a value which
 251  * contains commas, double each comma so it won't be recognized as the end of
 252  * the parameter.
 253  *
 254  * For more details of the parsing see above.
 255  *
 256  * Returns a pointer to the first element of dest (or the newly allocated copy)
 257  * or NULL in error cases
 258  */
 259 QEMUOptionParameter *parse_option_parameters(const char *param,
 260     QEMUOptionParameter *list, QEMUOptionParameter *dest)
 261 {
 262     QEMUOptionParameter *cur;
 263     QEMUOptionParameter *allocated = NULL;
 264     char name[256];
 265     char value[256];
 266     char *param_delim, *value_delim;
 267     char next_delim;
 268     size_t num_options;
 269
 270     if (list == NULL) {
 271         return NULL;
 272     }
 273
 274     if (dest == NULL) {
 275         // Count valid options
 276         num_options = 0;
 277         cur = list;
 278         while (cur->name) {
 279             num_options++;
 280             cur++;
 281         }
 282
 283         // Create a copy of the option list to fill in values
 284         dest = qemu_mallocz((num_options + 1) * sizeof(QEMUOptionParameter));
 285         allocated = dest;
 286         memcpy(dest, list, (num_options + 1) * sizeof(QEMUOptionParameter));
 287     }
 288
 289     while (*param) {
 290
 291         // Find parameter name and value in the string
 292         param_delim = strchr(param, ',');
 293         value_delim = strchr(param, '=');
 294
 295         if (value_delim && (value_delim < param_delim || !param_delim)) {
 296             next_delim = '=';
 297         } else {
 298             next_delim = ',';
 299             value_delim = NULL;
 300         }
 301
 302         param = get_opt_name(name, sizeof(name), param, next_delim);
 303         if (value_delim) {
 304             param = get_opt_value(value, sizeof(value), param + 1);
 305         }
 306         if (*param != '\0') {
 307             param++;
 308         }
 309
 310         // Set the parameter
 311         if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
 312             goto fail;
 313         }
 314     }
 315
 316     return dest;
 317
 318 fail:
 319     // Only free the list if it was newly allocated
 320     free_option_parameters(allocated);
 321     return NULL;
 322 }
 323
 324 /*
 325  * Prints all options of a list that have a value to stdout
 326  */
 327 void print_option_parameters(QEMUOptionParameter *list)
 328 {
 329     while (list && list->name) {
 330         switch (list->type) {
 331             case OPT_STRING:
 332                  if (list->value.s != NULL) {
 333                      printf("%s='%s' ", list->name, list->value.s);
 334                  }
 335                 break;
 336             case OPT_FLAG:
 337                 printf("%s=%s ", list->name, list->value.n ? "on" : "off");
 338                 break;
 339             case OPT_SIZE:
 340             case OPT_NUMBER:
 341                 printf("%s=%" PRId64 " ", list->name, list->value.n);
 342                 break;
 343             default:
 344                 printf("%s=(unkown type) ", list->name);
 345                 break;
 346         }
 347         list++;
 348     }
 349 }
 350
 351 /*
 352  * Prints an overview of all available options
 353  */
 354 void print_option_help(QEMUOptionParameter *list)
 355 {
 356     printf("Supported options:\n");
 357     while (list && list->name) {
 358         printf("%-16s %s\n", list->name,
 359             list->help ? list->help : "No description available");
 360         list++;
 361     }
 362 }