contrib/libarchive/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 tar.
  28  */
  29
  30 #include "bsdcat_platform.h"
  31 __FBSDID("$FreeBSD$");
  32
  33 #ifdef HAVE_ERRNO_H
  34 #include <errno.h>
  35 #endif
  36 #ifdef HAVE_STDLIB_H
  37 #include <stdlib.h>
  38 #endif
  39 #ifdef HAVE_STRING_H
  40 #include <string.h>
  41 #endif
  42
  43 #include "bsdcat.h"
  44 #include "err.h"
  45
  46 /*
  47  * Short options for tar.  Please keep this sorted.
  48  */
  49 static const char *short_options = "h";
  50
  51 /*
  52  * Long options for tar.  Please keep this list sorted.
  53  *
  54  * The symbolic names for options that lack a short equivalent are
  55  * defined in bsdcat.h.  Also note that so far I've found no need
  56  * to support optional arguments to long options.  That would be
  57  * a small change to the code below.
  58  */
  59
  60 static const struct bsdcat_option {
  61         const char *name;
  62         int required;      /* 1 if this option requires an argument. */
  63         int equivalent;    /* Equivalent short option. */
  64 } tar_longopts[] = {
  65         { "help",                 0, 'h' },
  66         { "version",              0, OPTION_VERSION },
  67         { NULL, 0, 0 }
  68 };
  69
  70 /*
  71  * This getopt implementation has two key features that common
  72  * getopt_long() implementations lack.  Apart from those, it's a
  73  * straightforward option parser, considerably simplified by not
  74  * needing to support the wealth of exotic getopt_long() features.  It
  75  * has, of course, been shamelessly tailored for bsdcat.  (If you're
  76  * looking for a generic getopt_long() implementation for your
  77  * project, I recommend Gregory Pietsch's public domain getopt_long()
  78  * implementation.)  The two additional features are:
  79  *
  80  * Old-style tar arguments: The original tar implementation treated
  81  * the first argument word as a list of single-character option
  82  * letters.  All arguments follow as separate words.  For example,
  83  *    tar xbf 32 /dev/tape
  84  * Here, the "xbf" is three option letters, "32" is the argument for
  85  * "b" and "/dev/tape" is the argument for "f".  We support this usage
  86  * if the first command-line argument does not begin with '-'.  We
  87  * also allow regular short and long options to follow, e.g.,
  88  *    tar xbf 32 /dev/tape -P --format=pax
  89  *
  90  * -W long options: There's an obscure GNU convention (only rarely
  91  * supported even there) that allows "-W option=argument" as an
  92  * alternative way to support long options.  This was supported in
  93  * early bsdcat as a way to access long options on platforms that did
  94  * not support getopt_long() and is preserved here for backwards
  95  * compatibility.  (Of course, if I'd started with a custom
  96  * command-line parser from the beginning, I would have had normal
  97  * long option support on every platform so that hack wouldn't have
  98  * been necessary.  Oh, well.  Some mistakes you just have to live
  99  * with.)
 100  *
 101  * TODO: We should be able to use this to pull files and intermingled
 102  * options (such as -C) from the command line in write mode.  That
 103  * will require a little rethinking of the argument handling in
 104  * bsdcat.c.
 105  *
 106  * TODO: If we want to support arbitrary command-line options from -T
 107  * input (as GNU tar does), we may need to extend this to handle option
 108  * words from sources other than argv/argc.  I'm not really sure if I
 109  * like that feature of GNU tar, so it's certainly not a priority.
 110  */
 111
 112 int
 113 bsdcat_getopt(struct bsdcat *bsdcat)
 114 {
 115         enum { state_start = 0, state_old_tar, state_next_word,
 116                state_short, state_long };
 117
 118         const struct bsdcat_option *popt, *match = NULL, *match2 = NULL;
 119         const char *p, *long_prefix = "--";
 120         size_t optlength;
 121         int opt = '?';
 122         int required = 0;
 123
 124         bsdcat->argument = NULL;
 125
 126         /* First time through, initialize everything. */
 127         if (bsdcat->getopt_state == state_start) {
 128                 /* Skip program name. */
 129                 ++bsdcat->argv;
 130                 --bsdcat->argc;
 131                 if (*bsdcat->argv == NULL)
 132                         return (-1);
 133                 /* Decide between "new style" and "old style" arguments. */
 134                 bsdcat->getopt_state = state_next_word;
 135         }
 136
 137         /*
 138          * We're ready to look at the next word in argv.
 139          */
 140         if (bsdcat->getopt_state == state_next_word) {
 141                 /* No more arguments, so no more options. */
 142                 if (bsdcat->argv[0] == NULL)
 143                         return (-1);
 144                 /* Doesn't start with '-', so no more options. */
 145                 if (bsdcat->argv[0][0] != '-')
 146                         return (-1);
 147                 /* "--" marks end of options; consume it and return. */
 148                 if (strcmp(bsdcat->argv[0], "--") == 0) {
 149                         ++bsdcat->argv;
 150                         --bsdcat->argc;
 151                         return (-1);
 152                 }
 153                 /* Get next word for parsing. */
 154                 bsdcat->getopt_word = *bsdcat->argv++;
 155                 --bsdcat->argc;
 156                 if (bsdcat->getopt_word[1] == '-') {
 157                         /* Set up long option parser. */
 158                         bsdcat->getopt_state = state_long;
 159                         bsdcat->getopt_word += 2; /* Skip leading '--' */
 160                 } else {
 161                         /* Set up short option parser. */
 162                         bsdcat->getopt_state = state_short;
 163                         ++bsdcat->getopt_word;  /* Skip leading '-' */
 164                 }
 165         }
 166
 167         /*
 168          * We're parsing a group of POSIX-style single-character options.
 169          */
 170         if (bsdcat->getopt_state == state_short) {
 171                 /* Peel next option off of a group of short options. */
 172                 opt = *bsdcat->getopt_word++;
 173                 if (opt == '\0') {
 174                         /* End of this group; recurse to get next option. */
 175                         bsdcat->getopt_state = state_next_word;
 176                         return bsdcat_getopt(bsdcat);
 177                 }
 178
 179                 /* Does this option take an argument? */
 180                 p = strchr(short_options, opt);
 181                 if (p == NULL)
 182                         return ('?');
 183                 if (p[1] == ':')
 184                         required = 1;
 185
 186                 /* If it takes an argument, parse that. */
 187                 if (required) {
 188                         /* If arg is run-in, bsdcat->getopt_word already points to it. */
 189                         if (bsdcat->getopt_word[0] == '\0') {
 190                                 /* Otherwise, pick up the next word. */
 191                                 bsdcat->getopt_word = *bsdcat->argv;
 192                                 if (bsdcat->getopt_word == NULL) {
 193                                         lafe_warnc(0,
 194                                             "Option -%c requires an argument",
 195                                             opt);
 196                                         return ('?');
 197                                 }
 198                                 ++bsdcat->argv;
 199                                 --bsdcat->argc;
 200                         }
 201                         if (opt == 'W') {
 202                                 bsdcat->getopt_state = state_long;
 203                                 long_prefix = "-W "; /* For clearer errors. */
 204                         } else {
 205                                 bsdcat->getopt_state = state_next_word;
 206                                 bsdcat->argument = bsdcat->getopt_word;
 207                         }
 208                 }
 209         }
 210
 211         /* We're reading a long option, including -W long=arg convention. */
 212         if (bsdcat->getopt_state == state_long) {
 213                 /* After this long option, we'll be starting a new word. */
 214                 bsdcat->getopt_state = state_next_word;
 215
 216                 /* Option name ends at '=' if there is one. */
 217                 p = strchr(bsdcat->getopt_word, '=');
 218                 if (p != NULL) {
 219                         optlength = (size_t)(p - bsdcat->getopt_word);
 220                         bsdcat->argument = (char *)(uintptr_t)(p + 1);
 221                 } else {
 222                         optlength = strlen(bsdcat->getopt_word);
 223                 }
 224
 225                 /* Search the table for an unambiguous match. */
 226                 for (popt = tar_longopts; popt->name != NULL; popt++) {
 227                         /* Short-circuit if first chars don't match. */
 228                         if (popt->name[0] != bsdcat->getopt_word[0])
 229                                 continue;
 230                         /* If option is a prefix of name in table, record it.*/
 231                         if (strncmp(bsdcat->getopt_word, popt->name, optlength) == 0) {
 232                                 match2 = match; /* Record up to two matches. */
 233                                 match = popt;
 234                                 /* If it's an exact match, we're done. */
 235                                 if (strlen(popt->name) == optlength) {
 236                                         match2 = NULL; /* Forget the others. */
 237                                         break;
 238                                 }
 239                         }
 240                 }
 241
 242                 /* Fail if there wasn't a unique match. */
 243                 if (match == NULL) {
 244                         lafe_warnc(0,
 245                             "Option %s%s is not supported",
 246                             long_prefix, bsdcat->getopt_word);
 247                         return ('?');
 248                 }
 249                 if (match2 != NULL) {
 250                         lafe_warnc(0,
 251                             "Ambiguous option %s%s (matches --%s and --%s)",
 252                             long_prefix, bsdcat->getopt_word, match->name, match2->name);
 253                         return ('?');
 254                 }
 255
 256                 /* We've found a unique match; does it need an argument? */
 257                 if (match->required) {
 258                         /* Argument required: get next word if necessary. */
 259                         if (bsdcat->argument == NULL) {
 260                                 bsdcat->argument = *bsdcat->argv;
 261                                 if (bsdcat->argument == NULL) {
 262                                         lafe_warnc(0,
 263                                             "Option %s%s requires an argument",
 264                                             long_prefix, match->name);
 265                                         return ('?');
 266                                 }
 267                                 ++bsdcat->argv;
 268                                 --bsdcat->argc;
 269                         }
 270                 } else {
 271                         /* Argument forbidden: fail if there is one. */
 272                         if (bsdcat->argument != NULL) {
 273                                 lafe_warnc(0,
 274                                     "Option %s%s does not allow an argument",
 275                                     long_prefix, match->name);
 276                                 return ('?');
 277                         }
 278                 }
 279                 return (match->equivalent);
 280         }
 281
 282         return (opt);
 283 }