tar/cmdline.c - third_party/libarchive - Git at Google

 /*-
  * Copyright (c) 2003-2008 Tim Kientzle
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 /*
  * Command line parser for tar.
  */

 #include "bsdtar_platform.h"
 __FBSDID("$FreeBSD$");

 #ifdef HAVE_ERRNO_H
 #include <errno.h>
 #endif
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif
 #ifdef HAVE_STRING_H
 #include <string.h>
 #endif

 #include "bsdtar.h"
 #include "err.h"

 /*
  * Short options for tar.  Please keep this sorted.
  */
 static const char *short_options
 	= "Bb:C:cf:HhI:JjkLlmnOoPpqrSs:T:tUuvW:wX:xyZz";

 /*
  * Long options for tar.  Please keep this list sorted.
  *
  * The symbolic names for options that lack a short equivalent are
  * defined in bsdtar.h.  Also note that so far I've found no need
  * to support optional arguments to long options.  That would be
  * a small change to the code below.
  */

 static struct option {
 	const char *name;
 	int required;      /* 1 if this option requires an argument. */
 	int equivalent;    /* Equivalent short option. */
 } tar_longopts[] = {
 	{ "absolute-paths",       0, 'P' },
 	{ "append",               0, 'r' },
 	{ "block-size",           1, 'b' },
 	{ "bunzip2",              0, 'j' },
 	{ "bzip",                 0, 'j' },
 	{ "bzip2",                0, 'j' },
 	{ "cd",                   1, 'C' },
 	{ "check-links",          0, OPTION_CHECK_LINKS },
 	{ "chroot",               0, OPTION_CHROOT },
 	{ "compress",             0, 'Z' },
 	{ "confirmation",         0, 'w' },
 	{ "create",               0, 'c' },
 	{ "dereference",	  0, 'L' },
 	{ "directory",            1, 'C' },
 	{ "exclude",              1, OPTION_EXCLUDE },
 	{ "exclude-from",         1, 'X' },
 	{ "extract",              0, 'x' },
 	{ "fast-read",            0, 'q' },
 	{ "file",                 1, 'f' },
 	{ "files-from",           1, 'T' },
 	{ "format",               1, OPTION_FORMAT },
 	{ "options",              1, OPTION_OPTIONS },
 	{ "gunzip",               0, 'z' },
 	{ "gzip",                 0, 'z' },
 	{ "help",                 0, OPTION_HELP },
 	{ "include",              1, OPTION_INCLUDE },
 	{ "interactive",          0, 'w' },
 	{ "insecure",             0, 'P' },
 	{ "keep-newer-files",     0, OPTION_KEEP_NEWER_FILES },
 	{ "keep-old-files",       0, 'k' },
 	{ "list",                 0, 't' },
 	{ "lzma",                 0, OPTION_LZMA },
 	{ "modification-time",    0, 'm' },
 	{ "newer",		  1, OPTION_NEWER_CTIME },
 	{ "newer-ctime",	  1, OPTION_NEWER_CTIME },
 	{ "newer-ctime-than",	  1, OPTION_NEWER_CTIME_THAN },
 	{ "newer-mtime",	  1, OPTION_NEWER_MTIME },
 	{ "newer-mtime-than",	  1, OPTION_NEWER_MTIME_THAN },
 	{ "newer-than",		  1, OPTION_NEWER_CTIME_THAN },
 	{ "nodump",               0, OPTION_NODUMP },
 	{ "norecurse",            0, 'n' },
 	{ "no-recursion",         0, 'n' },
 	{ "no-same-owner",	  0, OPTION_NO_SAME_OWNER },
 	{ "no-same-permissions",  0, OPTION_NO_SAME_PERMISSIONS },
 	{ "null",		  0, OPTION_NULL },
 	{ "numeric-owner",	  0, OPTION_NUMERIC_OWNER },
 	{ "one-file-system",	  0, OPTION_ONE_FILE_SYSTEM },
 	{ "posix",		  0, OPTION_POSIX },
 	{ "preserve-permissions", 0, 'p' },
 	{ "read-full-blocks",	  0, 'B' },
 	{ "same-owner",	          0, OPTION_SAME_OWNER },
 	{ "same-permissions",     0, 'p' },
 	{ "strip-components",	  1, OPTION_STRIP_COMPONENTS },
 	{ "to-stdout",            0, 'O' },
 	{ "totals",		  0, OPTION_TOTALS },
 	{ "uncompress",           0, 'Z' },
 	{ "unlink",		  0, 'U' },
 	{ "unlink-first",	  0, 'U' },
 	{ "update",               0, 'u' },
 	{ "use-compress-program", 1, OPTION_USE_COMPRESS_PROGRAM },
 	{ "verbose",              0, 'v' },
 	{ "version",              0, OPTION_VERSION },
 	{ "xz",                   0, 'J' },
 	{ NULL, 0, 0 }
 };

 /*
  * This getopt implementation has two key features that common
  * getopt_long() implementations lack.  Apart from those, it's a
  * straightforward option parser, considerably simplified by not
  * needing to support the wealth of exotic getopt_long() features.  It
  * has, of course, been shamelessly tailored for bsdtar.  (If you're
  * looking for a generic getopt_long() implementation for your
  * project, I recommend Gregory Pietsch's public domain getopt_long()
  * implementation.)  The two additional features are:
  *
  * Old-style tar arguments: The original tar implementation treated
  * the first argument word as a list of single-character option
  * letters.  All arguments follow as separate words.  For example,
  *    tar xbf 32 /dev/tape
  * Here, the "xbf" is three option letters, "32" is the argument for
  * "b" and "/dev/tape" is the argument for "f".  We support this usage
  * if the first command-line argument does not begin with '-'.  We
  * also allow regular short and long options to follow, e.g.,
  *    tar xbf 32 /dev/tape -P --format=pax
  *
  * -W long options: There's an obscure GNU convention (only rarely
  * supported even there) that allows "-W option=argument" as an
  * alternative way to support long options.  This was supported in
  * early bsdtar as a way to access long options on platforms that did
  * not support getopt_long() and is preserved here for backwards
  * compatibility.  (Of course, if I'd started with a custom
  * command-line parser from the beginning, I would have had normal
  * long option support on every platform so that hack wouldn't have
  * been necessary.  Oh, well.  Some mistakes you just have to live
  * with.)
  *
  * TODO: We should be able to use this to pull files and intermingled
  * options (such as -C) from the command line in write mode.  That
  * will require a little rethinking of the argument handling in
  * bsdtar.c.
  *
  * TODO: If we want to support arbitrary command-line options from -T
  * input (as GNU tar does), we may need to extend this to handle option
  * words from sources other than argv/arc.  I'm not really sure if I
  * like that feature of GNU tar, so it's certainly not a priority.
  */

 int
 bsdtar_getopt(struct bsdtar *bsdtar)
 {
 	enum { state_start = 0, state_old_tar, state_next_word,
 	       state_short, state_long };
 	static int state = state_start;
 	static char *opt_word;

 	const struct option *popt, *match = NULL, *match2 = NULL;
 	const char *p, *long_prefix = "--";
 	size_t optlength;
 	int opt = '?';
 	int required = 0;

 	bsdtar->optarg = NULL;

 	/* First time through, initialize everything. */
 	if (state == state_start) {
 		/* Skip program name. */
 		++bsdtar->argv;
 		--bsdtar->argc;
 		if (*bsdtar->argv == NULL)
 			return (-1);
 		/* Decide between "new style" and "old style" arguments. */
 		if (bsdtar->argv[0][0] == '-') {
 			state = state_next_word;
 		} else {
 			state = state_old_tar;
 			opt_word = *bsdtar->argv++;
 			--bsdtar->argc;
 		}
 	}

 	/*
 	 * We're parsing old-style tar arguments
 	 */
 	if (state == state_old_tar) {
 		/* Get the next option character. */
 		opt = *opt_word++;
 		if (opt == '\0') {
 			/* New-style args can follow old-style. */
 			state = state_next_word;
 		} else {
 			/* See if it takes an argument. */
 			p = strchr(short_options, opt);
 			if (p == NULL)
 				return ('?');
 			if (p[1] == ':') {
 				bsdtar->optarg = *bsdtar->argv;
 				if (bsdtar->optarg == NULL) {
 					lafe_warnc(0,
 					    "Option %c requires an argument",
 					    opt);
 					return ('?');
 				}
 				++bsdtar->argv;
 				--bsdtar->argc;
 			}
 		}
 	}

 	/*
 	 * We're ready to look at the next word in argv.
 	 */
 	if (state == state_next_word) {
 		/* No more arguments, so no more options. */
 		if (bsdtar->argv[0] == NULL)
 			return (-1);
 		/* Doesn't start with '-', so no more options. */
 		if (bsdtar->argv[0][0] != '-')
 			return (-1);
 		/* "--" marks end of options; consume it and return. */
 		if (strcmp(bsdtar->argv[0], "--") == 0) {
 			++bsdtar->argv;
 			--bsdtar->argc;
 			return (-1);
 		}
 		/* Get next word for parsing. */
 		opt_word = *bsdtar->argv++;
 		--bsdtar->argc;
 		if (opt_word[1] == '-') {
 			/* Set up long option parser. */
 			state = state_long;
 			opt_word += 2; /* Skip leading '--' */
 		} else {
 			/* Set up short option parser. */
 			state = state_short;
 			++opt_word;  /* Skip leading '-' */
 		}
 	}

 	/*
 	 * We're parsing a group of POSIX-style single-character options.
 	 */
 	if (state == state_short) {
 		/* Peel next option off of a group of short options. */
 		opt = *opt_word++;
 		if (opt == '\0') {
 			/* End of this group; recurse to get next option. */
 			state = state_next_word;
 			return bsdtar_getopt(bsdtar);
 		}

 		/* Does this option take an argument? */
 		p = strchr(short_options, opt);
 		if (p == NULL)
 			return ('?');
 		if (p[1] == ':')
 			required = 1;

 		/* If it takes an argument, parse that. */
 		if (required) {
 			/* If arg is run-in, opt_word already points to it. */
 			if (opt_word[0] == '\0') {
 				/* Otherwise, pick up the next word. */
 				opt_word = *bsdtar->argv;
 				if (opt_word == NULL) {
 					lafe_warnc(0,
 					    "Option -%c requires an argument",
 					    opt);
 					return ('?');
 				}
 				++bsdtar->argv;
 				--bsdtar->argc;
 			}
 			if (opt == 'W') {
 				state = state_long;
 				long_prefix = "-W "; /* For clearer errors. */
 			} else {
 				state = state_next_word;
 				bsdtar->optarg = opt_word;
 			}
 		}
 	}

 	/* We're reading a long option, including -W long=arg convention. */
 	if (state == state_long) {
 		/* After this long option, we'll be starting a new word. */
 		state = state_next_word;

 		/* Option name ends at '=' if there is one. */
 		p = strchr(opt_word, '=');
 		if (p != NULL) {
 			optlength = (size_t)(p - opt_word);
 			bsdtar->optarg = (char *)(uintptr_t)(p + 1);
 		} else {
 			optlength = strlen(opt_word);
 		}

 		/* Search the table for an unambiguous match. */
 		for (popt = tar_longopts; popt->name != NULL; popt++) {
 			/* Short-circuit if first chars don't match. */
 			if (popt->name[0] != opt_word[0])
 				continue;
 			/* If option is a prefix of name in table, record it.*/
 			if (strncmp(opt_word, popt->name, optlength) == 0) {
 				match2 = match; /* Record up to two matches. */
 				match = popt;
 				/* If it's an exact match, we're done. */
 				if (strlen(popt->name) == optlength) {
 					match2 = NULL; /* Forget the others. */
 					break;
 				}
 			}
 		}

 		/* Fail if there wasn't a unique match. */
 		if (match == NULL) {
 			lafe_warnc(0,
 			    "Option %s%s is not supported",
 			    long_prefix, opt_word);
 			return ('?');
 		}
 		if (match2 != NULL) {
 			lafe_warnc(0,
 			    "Ambiguous option %s%s (matches --%s and --%s)",
 			    long_prefix, opt_word, match->name, match2->name);
 			return ('?');
 		}

 		/* We've found a unique match; does it need an argument? */
 		if (match->required) {
 			/* Argument required: get next word if necessary. */
 			if (bsdtar->optarg == NULL) {
 				bsdtar->optarg = *bsdtar->argv;
 				if (bsdtar->optarg == NULL) {
 					lafe_warnc(0,
 					    "Option %s%s requires an argument",
 					    long_prefix, match->name);
 					return ('?');
 				}
 				++bsdtar->argv;
 				--bsdtar->argc;
 			}
 		} else {
 			/* Argument forbidden: fail if there is one. */
 			if (bsdtar->optarg != NULL) {
 				lafe_warnc(0,
 				    "Option %s%s does not allow an argument",
 				    long_prefix, match->name);
 				return ('?');
 			}
 		}
 		return (match->equivalent);
 	}

 	return (opt);
 }
	/*-
	* Copyright (c) 2003-2008 Tim Kientzle
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	/*
	* Command line parser for tar.
	*/

	#include "bsdtar_platform.h"
	__FBSDID("$FreeBSD$");

	#ifdef HAVE_ERRNO_H
	#include <errno.h>
	#endif
	#ifdef HAVE_STDLIB_H
	#include <stdlib.h>
	#endif
	#ifdef HAVE_STRING_H
	#include <string.h>
	#endif

	#include "bsdtar.h"
	#include "err.h"

	/*
	* Short options for tar. Please keep this sorted.
	*/
	static const char *short_options
	= "Bb:C:cf:HhI:JjkLlmnOoPpqrSs:T:tUuvW:wX:xyZz";

	/*
	* Long options for tar. Please keep this list sorted.
	*
	* The symbolic names for options that lack a short equivalent are
	* defined in bsdtar.h. Also note that so far I've found no need
	* to support optional arguments to long options. That would be
	* a small change to the code below.
	*/

	static struct option {
	const char *name;
	int required; /* 1 if this option requires an argument. */
	int equivalent; /* Equivalent short option. */
	} tar_longopts[] = {
	{ "absolute-paths", 0, 'P' },
	{ "append", 0, 'r' },
	{ "block-size", 1, 'b' },
	{ "bunzip2", 0, 'j' },
	{ "bzip", 0, 'j' },
	{ "bzip2", 0, 'j' },
	{ "cd", 1, 'C' },
	{ "check-links", 0, OPTION_CHECK_LINKS },
	{ "chroot", 0, OPTION_CHROOT },
	{ "compress", 0, 'Z' },
	{ "confirmation", 0, 'w' },
	{ "create", 0, 'c' },
	{ "dereference", 0, 'L' },
	{ "directory", 1, 'C' },
	{ "exclude", 1, OPTION_EXCLUDE },
	{ "exclude-from", 1, 'X' },
	{ "extract", 0, 'x' },
	{ "fast-read", 0, 'q' },
	{ "file", 1, 'f' },
	{ "files-from", 1, 'T' },
	{ "format", 1, OPTION_FORMAT },
	{ "options", 1, OPTION_OPTIONS },
	{ "gunzip", 0, 'z' },
	{ "gzip", 0, 'z' },
	{ "help", 0, OPTION_HELP },
	{ "include", 1, OPTION_INCLUDE },
	{ "interactive", 0, 'w' },
	{ "insecure", 0, 'P' },
	{ "keep-newer-files", 0, OPTION_KEEP_NEWER_FILES },
	{ "keep-old-files", 0, 'k' },
	{ "list", 0, 't' },
	{ "lzma", 0, OPTION_LZMA },
	{ "modification-time", 0, 'm' },
	{ "newer", 1, OPTION_NEWER_CTIME },
	{ "newer-ctime", 1, OPTION_NEWER_CTIME },
	{ "newer-ctime-than", 1, OPTION_NEWER_CTIME_THAN },
	{ "newer-mtime", 1, OPTION_NEWER_MTIME },
	{ "newer-mtime-than", 1, OPTION_NEWER_MTIME_THAN },
	{ "newer-than", 1, OPTION_NEWER_CTIME_THAN },
	{ "nodump", 0, OPTION_NODUMP },
	{ "norecurse", 0, 'n' },
	{ "no-recursion", 0, 'n' },
	{ "no-same-owner", 0, OPTION_NO_SAME_OWNER },
	{ "no-same-permissions", 0, OPTION_NO_SAME_PERMISSIONS },
	{ "null", 0, OPTION_NULL },
	{ "numeric-owner", 0, OPTION_NUMERIC_OWNER },
	{ "one-file-system", 0, OPTION_ONE_FILE_SYSTEM },
	{ "posix", 0, OPTION_POSIX },
	{ "preserve-permissions", 0, 'p' },
	{ "read-full-blocks", 0, 'B' },
	{ "same-owner", 0, OPTION_SAME_OWNER },
	{ "same-permissions", 0, 'p' },
	{ "strip-components", 1, OPTION_STRIP_COMPONENTS },
	{ "to-stdout", 0, 'O' },
	{ "totals", 0, OPTION_TOTALS },
	{ "uncompress", 0, 'Z' },
	{ "unlink", 0, 'U' },
	{ "unlink-first", 0, 'U' },
	{ "update", 0, 'u' },
	{ "use-compress-program", 1, OPTION_USE_COMPRESS_PROGRAM },
	{ "verbose", 0, 'v' },
	{ "version", 0, OPTION_VERSION },
	{ "xz", 0, 'J' },
	{ NULL, 0, 0 }
	};

	/*
	* This getopt implementation has two key features that common
	* getopt_long() implementations lack. Apart from those, it's a
	* straightforward option parser, considerably simplified by not
	* needing to support the wealth of exotic getopt_long() features. It
	* has, of course, been shamelessly tailored for bsdtar. (If you're
	* looking for a generic getopt_long() implementation for your
	* project, I recommend Gregory Pietsch's public domain getopt_long()
	* implementation.) The two additional features are:
	*
	* Old-style tar arguments: The original tar implementation treated
	* the first argument word as a list of single-character option
	* letters. All arguments follow as separate words. For example,
	* tar xbf 32 /dev/tape
	* Here, the "xbf" is three option letters, "32" is the argument for
	* "b" and "/dev/tape" is the argument for "f". We support this usage
	* if the first command-line argument does not begin with '-'. We
	* also allow regular short and long options to follow, e.g.,
	* tar xbf 32 /dev/tape -P --format=pax
	*
	* -W long options: There's an obscure GNU convention (only rarely
	* supported even there) that allows "-W option=argument" as an
	* alternative way to support long options. This was supported in
	* early bsdtar as a way to access long options on platforms that did
	* not support getopt_long() and is preserved here for backwards
	* compatibility. (Of course, if I'd started with a custom
	* command-line parser from the beginning, I would have had normal
	* long option support on every platform so that hack wouldn't have
	* been necessary. Oh, well. Some mistakes you just have to live
	* with.)
	*
	* TODO: We should be able to use this to pull files and intermingled
	* options (such as -C) from the command line in write mode. That
	* will require a little rethinking of the argument handling in
	* bsdtar.c.
	*
	* TODO: If we want to support arbitrary command-line options from -T
	* input (as GNU tar does), we may need to extend this to handle option
	* words from sources other than argv/arc. I'm not really sure if I
	* like that feature of GNU tar, so it's certainly not a priority.
	*/

	int
	bsdtar_getopt(struct bsdtar *bsdtar)
	{
	enum { state_start = 0, state_old_tar, state_next_word,
	state_short, state_long };
	static int state = state_start;
	static char *opt_word;

	const struct option popt, match = NULL, *match2 = NULL;
	const char p, long_prefix = "--";
	size_t optlength;
	int opt = '?';
	int required = 0;

	bsdtar->optarg = NULL;

	/* First time through, initialize everything. */
	if (state == state_start) {
	/* Skip program name. */
	++bsdtar->argv;
	--bsdtar->argc;
	if (*bsdtar->argv == NULL)
	return (-1);
	/* Decide between "new style" and "old style" arguments. */
	if (bsdtar->argv[0][0] == '-') {
	state = state_next_word;
	} else {
	state = state_old_tar;
	opt_word = *bsdtar->argv++;
	--bsdtar->argc;
	}
	}

	/*
	* We're parsing old-style tar arguments
	*/
	if (state == state_old_tar) {
	/* Get the next option character. */
	opt = *opt_word++;
	if (opt == '\0') {
	/* New-style args can follow old-style. */
	state = state_next_word;
	} else {
	/* See if it takes an argument. */
	p = strchr(short_options, opt);
	if (p == NULL)
	return ('?');
	if (p[1] == ':') {
	bsdtar->optarg = *bsdtar->argv;
	if (bsdtar->optarg == NULL) {
	lafe_warnc(0,
	"Option %c requires an argument",
	opt);
	return ('?');
	}
	++bsdtar->argv;
	--bsdtar->argc;
	}
	}
	}

	/*
	* We're ready to look at the next word in argv.
	*/
	if (state == state_next_word) {
	/* No more arguments, so no more options. */
	if (bsdtar->argv[0] == NULL)
	return (-1);
	/* Doesn't start with '-', so no more options. */
	if (bsdtar->argv[0][0] != '-')
	return (-1);
	/* "--" marks end of options; consume it and return. */
	if (strcmp(bsdtar->argv[0], "--") == 0) {
	++bsdtar->argv;
	--bsdtar->argc;
	return (-1);
	}
	/* Get next word for parsing. */
	opt_word = *bsdtar->argv++;
	--bsdtar->argc;
	if (opt_word[1] == '-') {
	/* Set up long option parser. */
	state = state_long;
	opt_word += 2; /* Skip leading '--' */
	} else {
	/* Set up short option parser. */
	state = state_short;
	++opt_word; /* Skip leading '-' */
	}
	}

	/*
	* We're parsing a group of POSIX-style single-character options.
	*/
	if (state == state_short) {
	/* Peel next option off of a group of short options. */
	opt = *opt_word++;
	if (opt == '\0') {
	/* End of this group; recurse to get next option. */
	state = state_next_word;
	return bsdtar_getopt(bsdtar);
	}

	/* Does this option take an argument? */
	p = strchr(short_options, opt);
	if (p == NULL)
	return ('?');
	if (p[1] == ':')
	required = 1;

	/* If it takes an argument, parse that. */
	if (required) {
	/* If arg is run-in, opt_word already points to it. */
	if (opt_word[0] == '\0') {
	/* Otherwise, pick up the next word. */
	opt_word = *bsdtar->argv;
	if (opt_word == NULL) {
	lafe_warnc(0,
	"Option -%c requires an argument",
	opt);
	return ('?');
	}
	++bsdtar->argv;
	--bsdtar->argc;
	}
	if (opt == 'W') {
	state = state_long;
	long_prefix = "-W "; /* For clearer errors. */
	} else {
	state = state_next_word;
	bsdtar->optarg = opt_word;
	}
	}
	}

	/* We're reading a long option, including -W long=arg convention. */
	if (state == state_long) {
	/* After this long option, we'll be starting a new word. */
	state = state_next_word;

	/* Option name ends at '=' if there is one. */
	p = strchr(opt_word, '=');
	if (p != NULL) {
	optlength = (size_t)(p - opt_word);
	bsdtar->optarg = (char *)(uintptr_t)(p + 1);
	} else {
	optlength = strlen(opt_word);
	}

	/* Search the table for an unambiguous match. */
	for (popt = tar_longopts; popt->name != NULL; popt++) {
	/* Short-circuit if first chars don't match. */
	if (popt->name[0] != opt_word[0])
	continue;
	/* If option is a prefix of name in table, record it.*/
	if (strncmp(opt_word, popt->name, optlength) == 0) {
	match2 = match; /* Record up to two matches. */
	match = popt;
	/* If it's an exact match, we're done. */
	if (strlen(popt->name) == optlength) {
	match2 = NULL; /* Forget the others. */
	break;
	}
	}
	}

	/* Fail if there wasn't a unique match. */
	if (match == NULL) {
	lafe_warnc(0,
	"Option %s%s is not supported",
	long_prefix, opt_word);
	return ('?');
	}
	if (match2 != NULL) {
	lafe_warnc(0,
	"Ambiguous option %s%s (matches --%s and --%s)",
	long_prefix, opt_word, match->name, match2->name);
	return ('?');
	}

	/* We've found a unique match; does it need an argument? */
	if (match->required) {
	/* Argument required: get next word if necessary. */
	if (bsdtar->optarg == NULL) {
	bsdtar->optarg = *bsdtar->argv;
	if (bsdtar->optarg == NULL) {
	lafe_warnc(0,
	"Option %s%s requires an argument",
	long_prefix, match->name);
	return ('?');
	}
	++bsdtar->argv;
	--bsdtar->argc;
	}
	} else {
	/* Argument forbidden: fail if there is one. */
	if (bsdtar->optarg != NULL) {
	lafe_warnc(0,
	"Option %s%s does not allow an argument",
	long_prefix, match->name);
	return ('?');
	}
	}
	return (match->equivalent);
	}

	return (opt);
	}