lib/libc/stdlib/getopt.c

   1 /*      $NetBSD: getopt.c,v 1.29 2014/06/05 22:00:22 christos Exp $     */
   2
   3 /*
   4  * Copyright (c) 1987, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __RCSID("$NetBSD: getopt.c,v 1.29 2014/06/05 22:00:22 christos Exp $");
  34
  35 #include "namespace.h"
  36
  37 #include <assert.h>
  38 #include <errno.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #ifdef __weak_alias
  45 __weak_alias(getopt,_getopt)
  46 #endif
  47
  48 int     opterr = 1,             /* if error message should be printed */
  49         optind = 1,             /* index into parent argv vector */
  50         optopt,                 /* character checked for validity */
  51         optreset;               /* reset getopt */
  52 char    *optarg;                /* argument associated with option */
  53
  54 #define BADCH   (int)'?'
  55 #define BADARG  (int)':'
  56 #define EMSG    ""
  57
  58 /*
  59  * getopt --
  60  *      Parse argc/argv argument vector.
  61  */
  62 int
  63 getopt(int nargc, char * const nargv[], const char *ostr)
  64 {
  65         static const char *place = EMSG;        /* option letter processing */
  66         char *oli;                              /* option letter list index */
  67
  68         _DIAGASSERT(nargv != NULL);
  69         _DIAGASSERT(ostr != NULL);
  70
  71         if (optreset || *place == 0) {          /* update scanning pointer */
  72                 optreset = 0;
  73                 place = nargv[optind];
  74                 if (optind >= nargc || *place++ != '-') {
  75                         /* Argument is absent or is not an option */
  76                         place = EMSG;
  77                         return (-1);
  78                 }
  79                 optopt = *place++;
  80                 if (optopt == '-' && *place == 0) {
  81                         /* "--" => end of options */
  82                         ++optind;
  83                         place = EMSG;
  84                         return (-1);
  85                 }
  86                 if (optopt == 0) {
  87                         /* Solitary '-', treat as a '-' option
  88                            if the program (eg su) is looking for it. */
  89                         place = EMSG;
  90                         if (strchr(ostr, '-') == NULL)
  91                                 return -1;
  92                         optopt = '-';
  93                 }
  94         } else
  95                 optopt = *place++;
  96
  97         /* See if option letter is one the caller wanted... */
  98         if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
  99                 if (*place == 0)
 100                         ++optind;
 101                 if (opterr && *ostr != ':')
 102                         (void)fprintf(stderr,
 103                             "%s: unknown option -- %c\n", getprogname(),
 104                             optopt);
 105                 return (BADCH);
 106         }
 107
 108         /* Does this option need an argument? */
 109         if (oli[1] != ':') {
 110                 /* don't need argument */
 111                 optarg = NULL;
 112                 if (*place == 0)
 113                         ++optind;
 114         } else {
 115                 /* Option-argument is either the rest of this argument or the
 116                    entire next argument. */
 117                 if (*place)
 118                         optarg = __UNCONST(place);
 119                 else if (oli[2] == ':')
 120                         /*
 121                          * GNU Extension, for optional arguments if the rest of
 122                          * the argument is empty, we return NULL
 123                          */
 124                         optarg = NULL;
 125                 else if (nargc > ++optind)
 126                         optarg = nargv[optind];
 127                 else {
 128                         /* option-argument absent */
 129                         place = EMSG;
 130                         if (*ostr == ':')
 131                                 return (BADARG);
 132                         if (opterr)
 133                                 (void)fprintf(stderr,
 134                                     "%s: option requires an argument -- %c\n",
 135                                     getprogname(), optopt);
 136                         return (BADCH);
 137                 }
 138                 place = EMSG;
 139                 ++optind;
 140         }
 141         return (optopt);                        /* return option letter */
 142 }