lib/getopt_long.c

   1 /*
   2  * getopt_long.c
   3  *
   4  * getopt_long(), or at least a common subset thereof:
   5  *
   6  * - Option reordering is not supported
   7  * - -W foo is not supported
   8  * - First optstring character "-" not supported.
   9  */
  10
  11 #include "config.h"
  12
  13 char *optarg;
  14 int optind, opterr, optopt;
  15
  16 static struct getopt_private_state {
  17     const char *optptr;
  18     const char *last_optstring;
  19     char *const *last_argv;
  20 } pvt;
  21
  22 static inline const char *option_matches(const char *arg_str,
  23                                          const char *opt_name)
  24 {
  25     while (*arg_str != '\0' && *arg_str != '=') {
  26         if (*arg_str++ != *opt_name++)
  27             return NULL;
  28     }
  29
  30     if (*opt_name)
  31         return NULL;
  32
  33     return arg_str;
  34 }
  35
  36 int getopt_long(int argc, char *const *argv, const char *optstring,
  37                 const struct option *longopts, int *longindex)
  38 {
  39     const char *carg;
  40     const char *osptr;
  41     int opt;
  42
  43     /* getopt() relies on a number of different global state
  44        variables, which can make this really confusing if there is
  45        more than one use of getopt() in the same program.  This
  46        attempts to detect that situation by detecting if the
  47        "optstring" or "argv" argument have changed since last time
  48        we were called; if so, reinitialize the query state. */
  49
  50     if (optstring != pvt.last_optstring || argv != pvt.last_argv ||
  51         optind < 1 || optind > argc) {
  52         /* optind doesn't match the current query */
  53         pvt.last_optstring = optstring;
  54         pvt.last_argv = argv;
  55         optind = 1;
  56         pvt.optptr = NULL;
  57     }
  58
  59     carg = argv[optind];
  60
  61     /* First, eliminate all non-option cases */
  62
  63     if (!carg || carg[0] != '-' || !carg[1])
  64         return -1;
  65
  66     if (carg[1] == '-') {
  67         const struct option *lo;
  68         const char *opt_end = NULL;
  69
  70         optind++;
  71
  72         /* Either it's a long option, or it's -- */
  73         if (!carg[2]) {
  74             /* It's -- */
  75             return -1;
  76         }
  77
  78         for (lo = longopts; lo->name; lo++) {
  79             if ((opt_end = option_matches(carg+2, lo->name)))
  80                 break;
  81         }
  82         if (!opt_end)
  83             return '?';
  84
  85         if (longindex)
  86             *longindex = lo-longopts;
  87
  88         if (*opt_end == '=') {
  89             if (lo->has_arg)
  90                 optarg = (char *)opt_end+1;
  91             else
  92                 return '?';
  93         } else if (lo->has_arg == 1) {
  94             if (!(optarg = argv[optind]))
  95                 return '?';
  96             optind++;
  97         }
  98
  99         if (lo->flag) {
 100             *lo->flag = lo->val;
 101             return 0;
 102         } else {
 103             return lo->val;
 104         }
 105     }
 106
 107     if ((uintptr_t) (pvt.optptr - carg) > (uintptr_t) strlen(carg)) {
 108         /* Someone frobbed optind, change to new opt. */
 109         pvt.optptr = carg + 1;
 110     }
 111
 112     opt = *pvt.optptr++;
 113
 114     if (opt != ':' && (osptr = strchr(optstring, opt))) {
 115         if (osptr[1] == ':') {
 116             if (*pvt.optptr) {
 117                 /* Argument-taking option with attached
 118                    argument */
 119                 optarg = (char *)pvt.optptr;
 120                 optind++;
 121             } else {
 122                 /* Argument-taking option with non-attached
 123                    argument */
 124                 if (argv[optind + 1]) {
 125                     optarg = (char *)argv[optind+1];
 126                     optind += 2;
 127                 } else {
 128                     /* Missing argument */
 129                     optind++;
 130                     return (optstring[0] == ':')
 131                         ? ':' : '?';
 132                 }
 133             }
 134             return opt;
 135         } else {
 136             /* Non-argument-taking option */
 137             /* pvt.optptr will remember the exact position to
 138                resume at */
 139             if (!*pvt.optptr)
 140                 optind++;
 141             return opt;
 142         }
 143     } else {
 144         /* Unknown option */
 145         optopt = opt;
 146         if (!*pvt.optptr)
 147             optind++;
 148         return '?';
 149     }
 150 }