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      1 /*
      2  * getopt.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 <stdint.h>
     12 #include <unistd.h>
     13 #include <string.h>
     14 #include <getopt.h>
     15 
     16 char *optarg;
     17 int optind, opterr, optopt;
     18 static struct getopt_private_state {
     19 	const char *optptr;
     20 	const char *last_optstring;
     21 	char *const *last_argv;
     22 } pvt;
     23 
     24 static inline const char *option_matches(const char *arg_str,
     25 					 const char *opt_name)
     26 {
     27 	while (*arg_str != '\0' && *arg_str != '=') {
     28 		if (*arg_str++ != *opt_name++)
     29 			return NULL;
     30 	}
     31 
     32 	if (*opt_name)
     33 		return NULL;
     34 
     35 	return arg_str;
     36 }
     37 
     38 int getopt_long(int argc, char *const *argv, const char *optstring,
     39 		const struct option *longopts, int *longindex)
     40 {
     41 	const char *carg;
     42 	const char *osptr;
     43 	int opt;
     44 
     45 	/* getopt() relies on a number of different global state
     46 	   variables, which can make this really confusing if there is
     47 	   more than one use of getopt() in the same program.  This
     48 	   attempts to detect that situation by detecting if the
     49 	   "optstring" or "argv" argument have changed since last time
     50 	   we were called; if so, reinitialize the query state. */
     51 
     52 	if (optstring != pvt.last_optstring || argv != pvt.last_argv ||
     53 	    optind < 1 || optind > argc) {
     54 		/* optind doesn't match the current query */
     55 		pvt.last_optstring = optstring;
     56 		pvt.last_argv = argv;
     57 		optind = 1;
     58 		pvt.optptr = NULL;
     59 	}
     60 
     61 	carg = argv[optind];
     62 
     63 	/* First, eliminate all non-option cases */
     64 
     65 	if (!carg || carg[0] != '-' || !carg[1])
     66 		return -1;
     67 
     68 	if (carg[1] == '-') {
     69 		const struct option *lo;
     70 		const char *opt_end = NULL;
     71 
     72 		optind++;
     73 
     74 		/* Either it's a long option, or it's -- */
     75 		if (!carg[2]) {
     76 			/* It's -- */
     77 			return -1;
     78 		}
     79 
     80 		for (lo = longopts; lo->name; lo++) {
     81 			if ((opt_end = option_matches(carg+2, lo->name)))
     82 			    break;
     83 		}
     84 		if (!opt_end)
     85 			return '?';
     86 
     87 		if (longindex)
     88 			*longindex = lo-longopts;
     89 
     90 		if (*opt_end == '=') {
     91 			if (lo->has_arg)
     92 				optarg = (char *)opt_end+1;
     93 			else
     94 				return '?';
     95 		} else if (lo->has_arg == 1) {
     96 			if (!(optarg = argv[optind]))
     97 				return '?';
     98 			optind++;
     99 		}
    100 
    101 		if (lo->flag) {
    102 			*lo->flag = lo->val;
    103 			return 0;
    104 		} else {
    105 			return lo->val;
    106 		}
    107 	}
    108 
    109 	if ((uintptr_t) (pvt.optptr - carg) > (uintptr_t) strlen(carg)) {
    110 		/* Someone frobbed optind, change to new opt. */
    111 		pvt.optptr = carg + 1;
    112 	}
    113 
    114 	opt = *pvt.optptr++;
    115 
    116 	if (opt != ':' && (osptr = strchr(optstring, opt))) {
    117 		if (osptr[1] == ':') {
    118 			if (*pvt.optptr) {
    119 				/* Argument-taking option with attached
    120 				   argument */
    121 				optarg = (char *)pvt.optptr;
    122 				optind++;
    123 			} else {
    124 				/* Argument-taking option with non-attached
    125 				   argument */
    126 				if (argv[optind + 1]) {
    127 					optarg = (char *)argv[optind+1];
    128 					optind += 2;
    129 				} else {
    130 					/* Missing argument */
    131 					optind++;
    132 					return (optstring[0] == ':')
    133 						? ':' : '?';
    134 				}
    135 			}
    136 			return opt;
    137 		} else {
    138 			/* Non-argument-taking option */
    139 			/* pvt.optptr will remember the exact position to
    140 			   resume at */
    141 			if (!*pvt.optptr)
    142 				optind++;
    143 			return opt;
    144 		}
    145 	} else {
    146 		/* Unknown option */
    147 		optopt = opt;
    148 		if (!*pvt.optptr)
    149 			optind++;
    150 		return '?';
    151 	}
    152 }
    153