cat/cmdline.c

   1 /*-
   2  * Copyright (c) 2003-2008 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 /*
  27  * Command line parser for bsdcat.
  28  */
  29
  30 #include "bsdcat_platform.h"
  31
  32 #ifdef HAVE_ERRNO_H
  33 #include <errno.h>
  34 #endif
  35 #ifdef HAVE_STDLIB_H
  36 #include <stdlib.h>
  37 #endif
  38 #ifdef HAVE_STRING_H
  39 #include <string.h>
  40 #endif
  41
  42 #include "bsdcat.h"
  43 #include "err.h"
  44
  45 /*
  46  * Short options for bsdcat.  Please keep this sorted.
  47  */
  48 static const char *short_options = "h";
  49
  50 /*
  51  * Long options for bsdcat.  Please keep this list sorted.
  52  *
  53  * The symbolic names for options that lack a short equivalent are
  54  * defined in bsdcat.h.  Also note that so far I've found no need
  55  * to support optional arguments to long options.  That would be
  56  * a small change to the code below.
  57  */
  58
  59 static const struct bsdcat_option {
  60         const char *name;
  61         int required;      /* 1 if this option requires an argument. */
  62         int equivalent;    /* Equivalent short option. */
  63 } bsdcat_longopts[] = {
  64         { "help",                 0, 'h' },
  65         { "version",              0, OPTION_VERSION },
  66         { NULL, 0, 0 }
  67 };
  68
  69 /*
  70  * This getopt implementation has two key features that common
  71  * getopt_long() implementations lack.  Apart from those, it's a
  72  * straightforward option parser, considerably simplified by not
  73  * needing to support the wealth of exotic getopt_long() features.  It
  74  * has, of course, been shamelessly tailored for bsdcat.  (If you're
  75  * looking for a generic getopt_long() implementation for your
  76  * project, I recommend Gregory Pietsch's public domain getopt_long()
  77  * implementation.)  The two additional features are:
  78  *
  79  * Old-style tar arguments: The original tar implementation treated
  80  * the first argument word as a list of single-character option
  81  * letters.  All arguments follow as separate words.  For example,
  82  *    tar xbf 32 /dev/tape
  83  * Here, the "xbf" is three option letters, "32" is the argument for
  84  * "b" and "/dev/tape" is the argument for "f".  We support this usage
  85  * if the first command-line argument does not begin with '-'.  We
  86  * also allow regular short and long options to follow, e.g.,
  87  *    tar xbf 32 /dev/tape -P --format=pax
  88  *
  89  * -W long options: There's an obscure GNU convention (only rarely
  90  * supported even there) that allows "-W option=argument" as an
  91  * alternative way to support long options.  This was supported in
  92  * early bsdtar as a way to access long options on platforms that did
  93  * not support getopt_long() and is preserved here for backwards
  94  * compatibility.  (Of course, if I'd started with a custom
  95  * command-line parser from the beginning, I would have had normal
  96  * long option support on every platform so that hack wouldn't have
  97  * been necessary.  Oh, well.  Some mistakes you just have to live
  98  * with.)
  99  *
 100  * TODO: We should be able to use this to pull files and intermingled
 101  * options (such as -C) from the command line in write mode.  That
 102  * will require a little rethinking of the argument handling in
 103  * bsdcat.c.
 104  *
 105  * TODO: If we want to support arbitrary command-line options from -T
 106  * input (as GNU tar does), we may need to extend this to handle option
 107  * words from sources other than argv/argc.  I'm not really sure if I
 108  * like that feature of GNU tar, so it's certainly not a priority.
 109  */
 110
 111 int
 112 bsdcat_getopt(struct bsdcat *bsdcat)
 113 {
 114         enum { state_start = 0, state_old_tar, state_next_word,
 115                state_short, state_long };
 116
 117         const struct bsdcat_option *popt, *match = NULL, *match2 = NULL;
 118         const char *p, *long_prefix = "--";
 119         size_t optlength;
 120         int opt = '?';
 121         int required = 0;
 122
 123         bsdcat->argument = NULL;
 124
 125         /* First time through, initialize everything. */
 126         if (bsdcat->getopt_state == state_start) {
 127                 /* Skip program name. */
 128                 ++bsdcat->argv;
 129                 --bsdcat->argc;
 130                 if (*bsdcat->argv == NULL)
 131                         return (-1);
 132                 /* Decide between "new style" and "old style" arguments. */
 133                 bsdcat->getopt_state = state_next_word;
 134         }
 135
 136         /*
 137          * We're ready to look at the next word in argv.
 138          */
 139         if (bsdcat->getopt_state == state_next_word) {
 140                 /* No more arguments, so no more options. */
 141                 if (bsdcat->argv[0] == NULL)
 142                         return (-1);
 143                 /* Doesn't start with '-', so no more options. */
 144                 if (bsdcat->argv[0][0] != '-')
 145                         return (-1);
 146                 /* "--" marks end of options; consume it and return. */
 147                 if (strcmp(bsdcat->argv[0], "--") == 0) {
 148                         ++bsdcat->argv;
 149                         --bsdcat->argc;
 150                         return (-1);
 151                 }
 152                 /* Get next word for parsing. */
 153                 bsdcat->getopt_word = *bsdcat->argv++;
 154                 --bsdcat->argc;
 155                 if (bsdcat->getopt_word[1] == '-') {
 156                         /* Set up long option parser. */
 157                         bsdcat->getopt_state = state_long;
 158                         bsdcat->getopt_word += 2; /* Skip leading '--' */
 159                 } else {
 160                         /* Set up short option parser. */
 161                         bsdcat->getopt_state = state_short;
 162                         ++bsdcat->getopt_word;  /* Skip leading '-' */
 163                 }
 164         }
 165
 166         /*
 167          * We're parsing a group of POSIX-style single-character options.
 168          */
 169         if (bsdcat->getopt_state == state_short) {
 170                 /* Peel next option off of a group of short options. */
 171                 opt = *bsdcat->getopt_word++;
 172                 if (opt == '\0') {
 173                         /* End of this group; recurse to get next option. */
 174                         bsdcat->getopt_state = state_next_word;
 175                         return bsdcat_getopt(bsdcat);
 176                 }
 177
 178                 /* Does this option take an argument? */
 179                 p = strchr(short_options, opt);
 180                 if (p == NULL)
 181                         return ('?');
 182                 if (p[1] == ':')
 183                         required = 1;
 184
 185                 /* If it takes an argument, parse that. */
 186                 if (required) {
 187                         /* If arg is run-in, bsdcat->getopt_word already points to it. */
 188                         if (bsdcat->getopt_word[0] == '\0') {
 189                                 /* Otherwise, pick up the next word. */
 190                                 bsdcat->getopt_word = *bsdcat->argv;
 191                                 if (bsdcat->getopt_word == NULL) {
 192                                         lafe_warnc(0,
 193                                             "Option -%c requires an argument",
 194                                             opt);
 195                                         return ('?');
 196                                 }
 197                                 ++bsdcat->argv;
 198                                 --bsdcat->argc;
 199                         }
 200                         if (opt == 'W') {
 201                                 bsdcat->getopt_state = state_long;
 202                                 long_prefix = "-W "; /* For clearer errors. */
 203                         } else {
 204                                 bsdcat->getopt_state = state_next_word;
 205                                 bsdcat->argument = bsdcat->getopt_word;
 206                         }
 207                 }
 208         }
 209
 210         /* We're reading a long option, including -W long=arg convention. */
 211         if (bsdcat->getopt_state == state_long) {
 212                 /* After this long option, we'll be starting a new word. */
 213                 bsdcat->getopt_state = state_next_word;
 214
 215                 /* Option name ends at '=' if there is one. */
 216                 p = strchr(bsdcat->getopt_word, '=');
 217                 if (p != NULL) {
 218                         optlength = (size_t)(p - bsdcat->getopt_word);
 219                         bsdcat->argument = (char *)(uintptr_t)(p + 1);
 220                 } else {
 221                         optlength = strlen(bsdcat->getopt_word);
 222                 }
 223
 224                 /* Search the table for an unambiguous match. */
 225                 for (popt = bsdcat_longopts; popt->name != NULL; popt++) {
 226                         /* Short-circuit if first chars don't match. */
 227                         if (popt->name[0] != bsdcat->getopt_word[0])
 228                                 continue;
 229                         /* If option is a prefix of name in table, record it.*/
 230                         if (strncmp(bsdcat->getopt_word, popt->name, optlength) == 0) {
 231                                 match2 = match; /* Record up to two matches. */
 232                                 match = popt;
 233                                 /* If it's an exact match, we're done. */
 234                                 if (strlen(popt->name) == optlength) {
 235                                         match2 = NULL; /* Forget the others. */
 236                                         break;
 237                                 }
 238                         }
 239                 }
 240
 241                 /* Fail if there wasn't a unique match. */
 242                 if (match == NULL) {
 243                         lafe_warnc(0,
 244                             "Option %s%s is not supported",
 245                             long_prefix, bsdcat->getopt_word);
 246                         return ('?');
 247                 }
 248                 if (match2 != NULL) {
 249                         lafe_warnc(0,
 250                             "Ambiguous option %s%s (matches --%s and --%s)",
 251                             long_prefix, bsdcat->getopt_word, match->name, match2->name);
 252                         return ('?');
 253                 }
 254
 255                 /* We've found a unique match; does it need an argument? */
 256                 if (match->required) {
 257                         /* Argument required: get next word if necessary. */
 258                         if (bsdcat->argument == NULL) {
 259                                 bsdcat->argument = *bsdcat->argv;
 260                                 if (bsdcat->argument == NULL) {
 261                                         lafe_warnc(0,
 262                                             "Option %s%s requires an argument",
 263                                             long_prefix, match->name);
 264                                         return ('?');
 265                                 }
 266                                 ++bsdcat->argv;
 267                                 --bsdcat->argc;
 268                         }
 269                 } else {
 270                         /* Argument forbidden: fail if there is one. */
 271                         if (bsdcat->argument != NULL) {
 272                                 lafe_warnc(0,
 273                                     "Option %s%s does not allow an argument",
 274                                     long_prefix, match->name);
 275                                 return ('?');
 276                         }
 277                 }
 278                 return (match->equivalent);
 279         }
 280
 281         return (opt);
 282 }