archival/cpio.c - busybox - Git at Google

 /* vi: set sw=4 ts=4: */
 /*
  * Mini cpio implementation for busybox
  *
  * Copyright (C) 2001 by Glenn McGrath
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  *
  * Limitations:
  * Doesn't check CRC's
  * Only supports new ASCII and CRC formats
  */
 //config:config CPIO
 //config:	bool "cpio (15 kb)"
 //config:	default y
 //config:	help
 //config:	cpio is an archival utility program used to create, modify, and
 //config:	extract contents from archives.
 //config:	cpio has 110 bytes of overheads for every stored file.
 //config:
 //config:	This implementation of cpio can extract cpio archives created in the
 //config:	"newc" or "crc" format.
 //config:
 //config:	Unless you have a specific application which requires cpio, you
 //config:	should probably say N here.
 //config:
 //config:config FEATURE_CPIO_O
 //config:	bool "Support archive creation"
 //config:	default y
 //config:	depends on CPIO
 //config:	help
 //config:	This implementation of cpio can create cpio archives in the "newc"
 //config:	format only.
 //config:
 //config:config FEATURE_CPIO_P
 //config:	bool "Support passthrough mode"
 //config:	default y
 //config:	depends on FEATURE_CPIO_O
 //config:	help
 //config:	Passthrough mode. Rarely used.

 //applet:IF_CPIO(APPLET(cpio, BB_DIR_BIN, BB_SUID_DROP))

 //kbuild:lib-$(CONFIG_CPIO) += cpio.o

 //usage:#define cpio_trivial_usage
 //usage:       "[-dmvu] [-F FILE] [-R USER[:GRP]]" IF_FEATURE_CPIO_O(" [-H newc]")
 //usage:       " [-ti"IF_FEATURE_CPIO_O("o")"]" IF_FEATURE_CPIO_P(" [-p DIR]")
 //usage:       " [EXTR_FILE]..."
 //usage:#define cpio_full_usage "\n\n"
 //usage:       "Extract (-i) or list (-t) files from a cpio archive"
 //usage:	IF_FEATURE_CPIO_O(", or"
 //usage:     "\ntake file list from stdin and create an archive (-o)"
 //usage:                IF_FEATURE_CPIO_P(" or copy files (-p)")
 //usage:	)
 //usage:     "\n"
 //usage:     "\nMain operation mode:"
 //usage:     "\n	-t	List"
 //usage:     "\n	-i	Extract EXTR_FILEs (or all)"
 //usage:	IF_FEATURE_CPIO_O(
 //usage:     "\n	-o	Create (requires -H newc)"
 //usage:	)
 //usage:	IF_FEATURE_CPIO_P(
 //usage:     "\n	-p DIR	Copy files to DIR"
 //usage:	)
 //usage:     "\nOptions:"
 //usage:	IF_FEATURE_CPIO_O(
 //usage:     "\n	-H newc	Archive format"
 //usage:	)
 //usage:     "\n	-d	Make leading directories"
 //usage:     "\n	-m	Preserve mtime"
 //usage:     "\n	-v	Verbose"
 //usage:     "\n	-u	Overwrite"
 //usage:     "\n	-F FILE	Input (-t,-i,-p) or output (-o) file"
 //usage:     "\n	-R USER[:GRP]	Set owner of created files"
 //usage:     "\n	-L	Dereference symlinks"
 //usage:     "\n	-0	Input is separated by NULs"

 /* GNU cpio 2.9 --help (abridged):

  Modes:
   -t, --list                 List the archive
   -i, --extract              Extract files from an archive
   -o, --create               Create the archive
   -p, --pass-through         Copy-pass mode

  Options valid in any mode:
       --block-size=SIZE      I/O block size = SIZE * 512 bytes
   -B                         I/O block size = 5120 bytes
   -c                         Use the old portable (ASCII) archive format
   -C, --io-size=NUMBER       I/O block size in bytes
   -f, --nonmatching          Only copy files that do not match given pattern
   -F, --file=FILE            Use FILE instead of standard input or output
   -H, --format=FORMAT        Use given archive FORMAT
   -M, --message=STRING       Print STRING when the end of a volume of the
                              backup media is reached
   -n, --numeric-uid-gid      If -v, show numeric UID and GID
       --quiet                Do not print the number of blocks copied
       --rsh-command=COMMAND  Use remote COMMAND instead of rsh
   -v, --verbose              Verbosely list the files processed
   -V, --dot                  Print a "." for each file processed
   -W, --warning=FLAG         Control warning display: 'none','truncate','all';
                              multiple options accumulate

  Options valid only in --extract mode:
   -b, --swap                 Swap both halfwords of words and bytes of
                              halfwords in the data (equivalent to -sS)
   -r, --rename               Interactively rename files
   -s, --swap-bytes           Swap the bytes of each halfword in the files
   -S, --swap-halfwords       Swap the halfwords of each word (4 bytes)
       --to-stdout            Extract files to standard output
   -E, --pattern-file=FILE    Read additional patterns specifying filenames to
                              extract or list from FILE
       --only-verify-crc      Verify CRC's, don't actually extract the files

  Options valid only in --create mode:
   -A, --append               Append to an existing archive
   -O FILE                    File to use instead of standard output

  Options valid only in --pass-through mode:
   -l, --link                 Link files instead of copying them, when possible

  Options valid in --extract and --create modes:
       --absolute-filenames   Do not strip file system prefix components from
                              the file names
       --no-absolute-filenames Create all files relative to the current dir

  Options valid in --create and --pass-through modes:
   -0, --null                 A list of filenames is terminated by a NUL
   -a, --reset-access-time    Reset the access times of files after reading them
   -I FILE                    File to use instead of standard input
   -L, --dereference          Dereference symbolic links (copy the files
                              that they point to instead of copying the links)
   -R, --owner=[USER][:.][GRP] Set owner of created files

  Options valid in --extract and --pass-through modes:
   -d, --make-directories     Create leading directories where needed
   -m, --preserve-modification-time  Retain mtime when creating files
       --no-preserve-owner    Do not change the ownership of the files
       --sparse               Write files with blocks of zeros as sparse files
   -u, --unconditional        Replace all files unconditionally
  */

 #include "libbb.h"
 #include "common_bufsiz.h"
 #include "bb_archive.h"

 enum {
 	OPT_EXTRACT            = (1 << 0),
 	OPT_TEST               = (1 << 1),
 	OPT_NUL_TERMINATED     = (1 << 2),
 	OPT_UNCONDITIONAL      = (1 << 3),
 	OPT_VERBOSE            = (1 << 4),
 	OPT_CREATE_LEADING_DIR = (1 << 5),
 	OPT_PRESERVE_MTIME     = (1 << 6),
 	OPT_DEREF              = (1 << 7),
 	OPT_FILE               = (1 << 8),
 	OPT_OWNER              = (1 << 9),
 	OPTBIT_OWNER = 9,
 	IF_FEATURE_CPIO_O(OPTBIT_CREATE     ,)
 	IF_FEATURE_CPIO_O(OPTBIT_FORMAT     ,)
 	IF_FEATURE_CPIO_P(OPTBIT_PASSTHROUGH,)
 	IF_LONG_OPTS(     OPTBIT_QUIET      ,)
 	IF_LONG_OPTS(     OPTBIT_2STDOUT    ,)
 	OPT_CREATE             = IF_FEATURE_CPIO_O((1 << OPTBIT_CREATE     )) + 0,
 	OPT_FORMAT             = IF_FEATURE_CPIO_O((1 << OPTBIT_FORMAT     )) + 0,
 	OPT_PASSTHROUGH        = IF_FEATURE_CPIO_P((1 << OPTBIT_PASSTHROUGH)) + 0,
 	OPT_QUIET              = IF_LONG_OPTS(     (1 << OPTBIT_QUIET      )) + 0,
 	OPT_2STDOUT            = IF_LONG_OPTS(     (1 << OPTBIT_2STDOUT    )) + 0,
 };

 #define OPTION_STR "it0uvdmLF:R:"

 struct globals {
 	struct bb_uidgid_t owner_ugid;
 } FIX_ALIASING;
 #define G (*(struct globals*)bb_common_bufsiz1)
 void BUG_cpio_globals_too_big(void);
 #define INIT_G() do { \
 	setup_common_bufsiz(); \
 	G.owner_ugid.uid = -1L; \
 	G.owner_ugid.gid = -1L; \
 } while (0)

 #if ENABLE_FEATURE_CPIO_O
 static off_t cpio_pad4(off_t size)
 {
 	int i;

 	i = (- size) & 3;
 	size += i;
 	while (--i >= 0)
 		bb_putchar('\0');
 	return size;
 }

 /* Return value will become exit code.
  * It's ok to exit instead of return. */
 static NOINLINE int cpio_o(void)
 {
 	struct name_s {
 		struct name_s *next;
 		char name[1];
 	};
 	struct inodes_s {
 		struct inodes_s *next;
 		struct name_s *names;
 		struct stat st;
 	};

 	struct inodes_s *links = NULL;
 	off_t bytes = 0; /* output bytes count */

 	while (1) {
 		const char *name;
 		char *line;
 		struct stat st;

 		line = (option_mask32 & OPT_NUL_TERMINATED)
 				? bb_get_chunk_from_file(stdin, NULL)
 				: xmalloc_fgetline(stdin);

 		if (line) {
 			/* Strip leading "./[./]..." from the filename */
 			name = line;
 			while (name[0] == '.' && name[1] == '/') {
 				while (*++name == '/')
 					continue;
 			}
 			if (!*name) { /* line is empty */
 				free(line);
 				continue;
 			}
 			if ((option_mask32 & OPT_DEREF)
 					? stat(name, &st)
 					: lstat(name, &st)
 			) {
  abort_cpio_o:
 				bb_simple_perror_msg_and_die(name);
 			}

 			if (G.owner_ugid.uid != (uid_t)-1L)
 				st.st_uid = G.owner_ugid.uid;
 			if (G.owner_ugid.gid != (gid_t)-1L)
 				st.st_gid = G.owner_ugid.gid;

 			if (!(S_ISLNK(st.st_mode) || S_ISREG(st.st_mode)))
 				st.st_size = 0; /* paranoia */

 			/* Store hardlinks for later processing, dont output them */
 			if (!S_ISDIR(st.st_mode) && st.st_nlink > 1) {
 				struct name_s *n;
 				struct inodes_s *l;

 				/* Do we have this hardlink remembered? */
 				l = links;
 				while (1) {
 					if (l == NULL) {
 						/* Not found: add new item to "links" list */
 						l = xzalloc(sizeof(*l));
 						l->st = st;
 						l->next = links;
 						links = l;
 						break;
 					}
 					if (l->st.st_ino == st.st_ino) {
 						/* found */
 						break;
 					}
 					l = l->next;
 				}
 				/* Add new name to "l->names" list */
 				n = xmalloc(sizeof(*n) + strlen(name));
 				strcpy(n->name, name);
 				n->next = l->names;
 				l->names = n;

 				free(line);
 				continue;
 			}
 		} else { /* line == NULL: EOF */
  next_link:
 			if (links) {
 				/* Output hardlink's data */
 				st = links->st;
 				name = links->names->name;
 				links->names = links->names->next;
 				/* GNU cpio is reported to emit file data
 				 * only for the last instance. Mimic that. */
 				if (links->names == NULL)
 					links = links->next;
 				else
 					st.st_size = 0;
 				/* NB: we leak links->names and/or links,
 				 * this is intended (we exit soon anyway) */
 			} else {
 				/* If no (more) hardlinks to output,
 				 * output "trailer" entry */
 				name = cpio_TRAILER;
 				/* st.st_size == 0 is a must, but for uniformity
 				 * in the output, we zero out everything */
 				memset(&st, 0, sizeof(st));
 				/* st.st_nlink = 1; - GNU cpio does this */
 			}
 		}

 		bytes += printf("070701"
 				"%08X%08X%08X%08X%08X%08X%08X"
 				"%08X%08X%08X%08X" /* GNU cpio uses uppercase hex */
 				/* strlen+1: */ "%08X"
 				/* chksum: */   "00000000" /* (only for "070702" files) */
 				/* name,NUL: */ "%s%c",
 				(unsigned)(uint32_t) st.st_ino,
 				(unsigned)(uint32_t) st.st_mode,
 				(unsigned)(uint32_t) st.st_uid,
 				(unsigned)(uint32_t) st.st_gid,
 				(unsigned)(uint32_t) st.st_nlink,
 				(unsigned)(uint32_t) st.st_mtime,
 				(unsigned)(uint32_t) st.st_size,
 				(unsigned)(uint32_t) major(st.st_dev),
 				(unsigned)(uint32_t) minor(st.st_dev),
 				(unsigned)(uint32_t) major(st.st_rdev),
 				(unsigned)(uint32_t) minor(st.st_rdev),
 				(unsigned)(strlen(name) + 1),
 				name, '\0');
 		bytes = cpio_pad4(bytes);

 		if (st.st_size) {
 			if (S_ISLNK(st.st_mode)) {
 				char *lpath = xmalloc_readlink_or_warn(name);
 				if (!lpath)
 					goto abort_cpio_o;
 				bytes += printf("%s", lpath);
 				free(lpath);
 			} else { /* S_ISREG */
 				int fd = xopen(name, O_RDONLY);
 				fflush_all();
 				/* We must abort if file got shorter too! */
 				bb_copyfd_exact_size(fd, STDOUT_FILENO, st.st_size);
 				bytes += st.st_size;
 				close(fd);
 			}
 			bytes = cpio_pad4(bytes);
 		}

 		if (!line) {
 			if (name != cpio_TRAILER)
 				goto next_link;
 			/* TODO: GNU cpio pads trailer to 512 bytes, do we want that? */
 			return EXIT_SUCCESS;
 		}

 		free(line);
 	} /* end of "while (1)" */
 }
 #endif

 int cpio_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int cpio_main(int argc UNUSED_PARAM, char **argv)
 {
 	archive_handle_t *archive_handle;
 	char *cpio_filename;
 	char *cpio_owner;
 	IF_FEATURE_CPIO_O(const char *cpio_fmt = "";)
 	unsigned opt;
 #if ENABLE_LONG_OPTS
 	const char *long_opts =
 		"extract\0"      No_argument       "i"
 		"list\0"         No_argument       "t"
 #if ENABLE_FEATURE_CPIO_O
 		"create\0"       No_argument       "o"
 		"format\0"       Required_argument "H"
 #if ENABLE_FEATURE_CPIO_P
 		"pass-through\0" No_argument       "p"
 #endif
 #endif
 		"owner\0"        Required_argument "R"
 		"verbose\0"      No_argument       "v"
 		"null\0"         No_argument       "0"
 		"quiet\0"        No_argument       "\xff"
 		"to-stdout\0"    No_argument       "\xfe"
 		;
 #endif

 	INIT_G();
 	archive_handle = init_handle();
 	/* archive_handle->src_fd = STDIN_FILENO; - done by init_handle */
 	archive_handle->ah_flags = ARCHIVE_EXTRACT_NEWER;

 	/* As of now we do not enforce this: */
 	/* -i,-t,-o,-p are mutually exclusive */
 	/* -u,-d,-m make sense only with -i or -p */
 	/* -L makes sense only with -o or -p */

 #if !ENABLE_FEATURE_CPIO_O
 	opt = getopt32long(argv, OPTION_STR, long_opts, &cpio_filename, &cpio_owner);
 #else
 	opt = getopt32long(argv, OPTION_STR "oH:" IF_FEATURE_CPIO_P("p"), long_opts,
 		       &cpio_filename, &cpio_owner, &cpio_fmt);
 #endif
 	argv += optind;
 	if (opt & OPT_OWNER) { /* -R */
 		parse_chown_usergroup_or_die(&G.owner_ugid, cpio_owner);
 		archive_handle->cpio__owner = G.owner_ugid;
 	}
 #if !ENABLE_FEATURE_CPIO_O
 	if (opt & OPT_FILE) { /* -F */
 		xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
 	}
 #else
 	if ((opt & (OPT_FILE|OPT_CREATE)) == OPT_FILE) { /* -F without -o */
 		xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
 	}
 	if (opt & OPT_PASSTHROUGH) {
 		pid_t pid;
 		struct fd_pair pp;

 		if (argv[0] == NULL)
 			bb_show_usage();
 		if (opt & OPT_CREATE_LEADING_DIR)
 			mkdir(argv[0], 0777);
 		/* Crude existence check:
 		 * close(xopen(argv[0], O_RDONLY | O_DIRECTORY));
 		 * We can also xopen, fstat, IS_DIR, later fchdir.
 		 * This would check for existence earlier and cleaner.
 		 * As it stands now, if we fail xchdir later,
 		 * child dies on EPIPE, unless it caught
 		 * a diffrerent problem earlier.
 		 * This is good enough for now.
 		 */
 #if !BB_MMU
 		pp.rd = 3;
 		pp.wr = 4;
 		if (!re_execed) {
 			close(3);
 			close(4);
 			xpiped_pair(pp);
 		}
 #else
 		xpiped_pair(pp);
 #endif
 		pid = fork_or_rexec(argv - optind);
 		if (pid == 0) { /* child */
 			close(pp.rd);
 			xmove_fd(pp.wr, STDOUT_FILENO);
 			goto dump;
 		}
 		/* parent */
 		USE_FOR_NOMMU(argv[-optind][0] &= 0x7f); /* undo fork_or_rexec() damage */
 		xchdir(*argv++);
 		close(pp.wr);
 		xmove_fd(pp.rd, STDIN_FILENO);
 		//opt &= ~OPT_PASSTHROUGH;
 		opt |= OPT_EXTRACT;
 		goto skip;
 	}
 	/* -o */
 	if (opt & OPT_CREATE) {
 		if (cpio_fmt[0] != 'n') /* we _require_ "-H newc" */
 			bb_show_usage();
 		if (opt & OPT_FILE) {
 			xmove_fd(xopen(cpio_filename, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO);
 		}
  dump:
 		return cpio_o();
 	}
  skip:
 #endif

 	/* One of either extract or test options must be given */
 	if ((opt & (OPT_TEST | OPT_EXTRACT)) == 0) {
 		bb_show_usage();
 	}

 	if (opt & OPT_TEST) {
 		/* if both extract and test options are given, ignore extract option */
 		opt &= ~OPT_EXTRACT;
 		archive_handle->action_header = header_list;
 	}
 	if (opt & OPT_EXTRACT) {
 		archive_handle->action_data = data_extract_all;
 		if (opt & OPT_2STDOUT)
 			archive_handle->action_data = data_extract_to_stdout;
 	}
 	if (opt & OPT_UNCONDITIONAL) {
 		archive_handle->ah_flags |= ARCHIVE_UNLINK_OLD;
 		archive_handle->ah_flags &= ~ARCHIVE_EXTRACT_NEWER;
 	}
 	if (opt & OPT_VERBOSE) {
 		if (archive_handle->action_header == header_list) {
 			archive_handle->action_header = header_verbose_list;
 		} else {
 			archive_handle->action_header = header_list;
 		}
 	}
 	if (opt & OPT_CREATE_LEADING_DIR) {
 		archive_handle->ah_flags |= ARCHIVE_CREATE_LEADING_DIRS;
 	}
 	if (opt & OPT_PRESERVE_MTIME) {
 		archive_handle->ah_flags |= ARCHIVE_RESTORE_DATE;
 	}

 	while (*argv) {
 		archive_handle->filter = filter_accept_list;
 		llist_add_to(&archive_handle->accept, *argv);
 		argv++;
 	}

 	/* see get_header_cpio */
 	archive_handle->cpio__blocks = (off_t)-1;
 	while (get_header_cpio(archive_handle) == EXIT_SUCCESS)
 		continue;

 	create_links_from_list(archive_handle->link_placeholders);

 	if (archive_handle->cpio__blocks != (off_t)-1
 	 && !(opt & OPT_QUIET)
 	) {
 		fprintf(stderr, "%"OFF_FMT"u blocks\n", archive_handle->cpio__blocks);
 	}

 	return EXIT_SUCCESS;
 }
	/* vi: set sw=4 ts=4: */
	/*
	* Mini cpio implementation for busybox
	*
	* Copyright (C) 2001 by Glenn McGrath
	*
	* Licensed under GPLv2 or later, see file LICENSE in this source tree.
	*
	* Limitations:
	* Doesn't check CRC's
	* Only supports new ASCII and CRC formats
	*/
	//config:config CPIO
	//config: bool "cpio (15 kb)"
	//config: default y
	//config: help
	//config: cpio is an archival utility program used to create, modify, and
	//config: extract contents from archives.
	//config: cpio has 110 bytes of overheads for every stored file.
	//config:
	//config: This implementation of cpio can extract cpio archives created in the
	//config: "newc" or "crc" format.
	//config:
	//config: Unless you have a specific application which requires cpio, you
	//config: should probably say N here.
	//config:
	//config:config FEATURE_CPIO_O
	//config: bool "Support archive creation"
	//config: default y
	//config: depends on CPIO
	//config: help
	//config: This implementation of cpio can create cpio archives in the "newc"
	//config: format only.
	//config:
	//config:config FEATURE_CPIO_P
	//config: bool "Support passthrough mode"
	//config: default y
	//config: depends on FEATURE_CPIO_O
	//config: help
	//config: Passthrough mode. Rarely used.

	//applet:IF_CPIO(APPLET(cpio, BB_DIR_BIN, BB_SUID_DROP))

	//kbuild:lib-$(CONFIG_CPIO) += cpio.o

	//usage:#define cpio_trivial_usage
	//usage: "[-dmvu] [-F FILE] [-R USER[:GRP]]" IF_FEATURE_CPIO_O(" [-H newc]")
	//usage: " [-ti"IF_FEATURE_CPIO_O("o")"]" IF_FEATURE_CPIO_P(" [-p DIR]")
	//usage: " [EXTR_FILE]..."
	//usage:#define cpio_full_usage "\n\n"
	//usage: "Extract (-i) or list (-t) files from a cpio archive"
	//usage: IF_FEATURE_CPIO_O(", or"
	//usage: "\ntake file list from stdin and create an archive (-o)"
	//usage: IF_FEATURE_CPIO_P(" or copy files (-p)")
	//usage: )
	//usage: "\n"
	//usage: "\nMain operation mode:"
	//usage: "\n -t List"
	//usage: "\n -i Extract EXTR_FILEs (or all)"
	//usage: IF_FEATURE_CPIO_O(
	//usage: "\n -o Create (requires -H newc)"
	//usage: )
	//usage: IF_FEATURE_CPIO_P(
	//usage: "\n -p DIR Copy files to DIR"
	//usage: )
	//usage: "\nOptions:"
	//usage: IF_FEATURE_CPIO_O(
	//usage: "\n -H newc Archive format"
	//usage: )
	//usage: "\n -d Make leading directories"
	//usage: "\n -m Preserve mtime"
	//usage: "\n -v Verbose"
	//usage: "\n -u Overwrite"
	//usage: "\n -F FILE Input (-t,-i,-p) or output (-o) file"
	//usage: "\n -R USER[:GRP] Set owner of created files"
	//usage: "\n -L Dereference symlinks"
	//usage: "\n -0 Input is separated by NULs"

	/* GNU cpio 2.9 --help (abridged):

	Modes:
	-t, --list List the archive
	-i, --extract Extract files from an archive
	-o, --create Create the archive
	-p, --pass-through Copy-pass mode

	Options valid in any mode:
	--block-size=SIZE I/O block size = SIZE * 512 bytes
	-B I/O block size = 5120 bytes
	-c Use the old portable (ASCII) archive format
	-C, --io-size=NUMBER I/O block size in bytes
	-f, --nonmatching Only copy files that do not match given pattern
	-F, --file=FILE Use FILE instead of standard input or output
	-H, --format=FORMAT Use given archive FORMAT
	-M, --message=STRING Print STRING when the end of a volume of the
	backup media is reached
	-n, --numeric-uid-gid If -v, show numeric UID and GID
	--quiet Do not print the number of blocks copied
	--rsh-command=COMMAND Use remote COMMAND instead of rsh
	-v, --verbose Verbosely list the files processed
	-V, --dot Print a "." for each file processed
	-W, --warning=FLAG Control warning display: 'none','truncate','all';
	multiple options accumulate

	Options valid only in --extract mode:
	-b, --swap Swap both halfwords of words and bytes of
	halfwords in the data (equivalent to -sS)
	-r, --rename Interactively rename files
	-s, --swap-bytes Swap the bytes of each halfword in the files
	-S, --swap-halfwords Swap the halfwords of each word (4 bytes)
	--to-stdout Extract files to standard output
	-E, --pattern-file=FILE Read additional patterns specifying filenames to
	extract or list from FILE
	--only-verify-crc Verify CRC's, don't actually extract the files

	Options valid only in --create mode:
	-A, --append Append to an existing archive
	-O FILE File to use instead of standard output

	Options valid only in --pass-through mode:
	-l, --link Link files instead of copying them, when possible

	Options valid in --extract and --create modes:
	--absolute-filenames Do not strip file system prefix components from
	the file names
	--no-absolute-filenames Create all files relative to the current dir

	Options valid in --create and --pass-through modes:
	-0, --null A list of filenames is terminated by a NUL
	-a, --reset-access-time Reset the access times of files after reading them
	-I FILE File to use instead of standard input
	-L, --dereference Dereference symbolic links (copy the files
	that they point to instead of copying the links)
	-R, --owner=[USER][:.][GRP] Set owner of created files

	Options valid in --extract and --pass-through modes:
	-d, --make-directories Create leading directories where needed
	-m, --preserve-modification-time Retain mtime when creating files
	--no-preserve-owner Do not change the ownership of the files
	--sparse Write files with blocks of zeros as sparse files
	-u, --unconditional Replace all files unconditionally
	*/

	#include "libbb.h"
	#include "common_bufsiz.h"
	#include "bb_archive.h"

	enum {
	OPT_EXTRACT = (1 << 0),
	OPT_TEST = (1 << 1),
	OPT_NUL_TERMINATED = (1 << 2),
	OPT_UNCONDITIONAL = (1 << 3),
	OPT_VERBOSE = (1 << 4),
	OPT_CREATE_LEADING_DIR = (1 << 5),
	OPT_PRESERVE_MTIME = (1 << 6),
	OPT_DEREF = (1 << 7),
	OPT_FILE = (1 << 8),
	OPT_OWNER = (1 << 9),
	OPTBIT_OWNER = 9,
	IF_FEATURE_CPIO_O(OPTBIT_CREATE ,)
	IF_FEATURE_CPIO_O(OPTBIT_FORMAT ,)
	IF_FEATURE_CPIO_P(OPTBIT_PASSTHROUGH,)
	IF_LONG_OPTS( OPTBIT_QUIET ,)
	IF_LONG_OPTS( OPTBIT_2STDOUT ,)
	OPT_CREATE = IF_FEATURE_CPIO_O((1 << OPTBIT_CREATE )) + 0,
	OPT_FORMAT = IF_FEATURE_CPIO_O((1 << OPTBIT_FORMAT )) + 0,
	OPT_PASSTHROUGH = IF_FEATURE_CPIO_P((1 << OPTBIT_PASSTHROUGH)) + 0,
	OPT_QUIET = IF_LONG_OPTS( (1 << OPTBIT_QUIET )) + 0,
	OPT_2STDOUT = IF_LONG_OPTS( (1 << OPTBIT_2STDOUT )) + 0,
	};

	#define OPTION_STR "it0uvdmLF:R:"

	struct globals {
	struct bb_uidgid_t owner_ugid;
	} FIX_ALIASING;
	#define G ((struct globals)bb_common_bufsiz1)
	void BUG_cpio_globals_too_big(void);
	#define INIT_G() do { \
	setup_common_bufsiz(); \
	G.owner_ugid.uid = -1L; \
	G.owner_ugid.gid = -1L; \
	} while (0)

	#if ENABLE_FEATURE_CPIO_O
	static off_t cpio_pad4(off_t size)
	{
	int i;

	i = (- size) & 3;
	size += i;
	while (--i >= 0)
	bb_putchar('\0');
	return size;
	}

	/* Return value will become exit code.
	* It's ok to exit instead of return. */
	static NOINLINE int cpio_o(void)
	{
	struct name_s {
	struct name_s *next;
	char name[1];
	};
	struct inodes_s {
	struct inodes_s *next;
	struct name_s *names;
	struct stat st;
	};

	struct inodes_s *links = NULL;
	off_t bytes = 0; /* output bytes count */

	while (1) {
	const char *name;
	char *line;
	struct stat st;

	line = (option_mask32 & OPT_NUL_TERMINATED)
	? bb_get_chunk_from_file(stdin, NULL)
	: xmalloc_fgetline(stdin);

	if (line) {
	/* Strip leading "./[./]..." from the filename */
	name = line;
	while (name[0] == '.' && name[1] == '/') {
	while (*++name == '/')
	continue;
	}
	if (!name) { / line is empty */
	free(line);
	continue;
	}
	if ((option_mask32 & OPT_DEREF)
	? stat(name, &st)
	: lstat(name, &st)
	) {
	abort_cpio_o:
	bb_simple_perror_msg_and_die(name);
	}

	if (G.owner_ugid.uid != (uid_t)-1L)
	st.st_uid = G.owner_ugid.uid;
	if (G.owner_ugid.gid != (gid_t)-1L)
	st.st_gid = G.owner_ugid.gid;

	if (!(S_ISLNK(st.st_mode) \|\| S_ISREG(st.st_mode)))
	st.st_size = 0; /* paranoia */

	/* Store hardlinks for later processing, dont output them */
	if (!S_ISDIR(st.st_mode) && st.st_nlink > 1) {
	struct name_s *n;
	struct inodes_s *l;

	/* Do we have this hardlink remembered? */
	l = links;
	while (1) {
	if (l == NULL) {
	/* Not found: add new item to "links" list */
	l = xzalloc(sizeof(*l));
	l->st = st;
	l->next = links;
	links = l;
	break;
	}
	if (l->st.st_ino == st.st_ino) {
	/* found */
	break;
	}
	l = l->next;
	}
	/* Add new name to "l->names" list */
	n = xmalloc(sizeof(*n) + strlen(name));
	strcpy(n->name, name);
	n->next = l->names;
	l->names = n;

	free(line);
	continue;
	}
	} else { /* line == NULL: EOF */
	next_link:
	if (links) {
	/* Output hardlink's data */
	st = links->st;
	name = links->names->name;
	links->names = links->names->next;
	/* GNU cpio is reported to emit file data
	* only for the last instance. Mimic that. */
	if (links->names == NULL)
	links = links->next;
	else
	st.st_size = 0;
	/* NB: we leak links->names and/or links,
	* this is intended (we exit soon anyway) */
	} else {
	/* If no (more) hardlinks to output,
	* output "trailer" entry */
	name = cpio_TRAILER;
	/* st.st_size == 0 is a must, but for uniformity
	* in the output, we zero out everything */
	memset(&st, 0, sizeof(st));
	/* st.st_nlink = 1; - GNU cpio does this */
	}
	}

	bytes += printf("070701"
	"%08X%08X%08X%08X%08X%08X%08X"
	"%08X%08X%08X%08X" /* GNU cpio uses uppercase hex */
	/* strlen+1: */ "%08X"
	/* chksum: / "00000000" / (only for "070702" files) */
	/* name,NUL: */ "%s%c",
	(unsigned)(uint32_t) st.st_ino,
	(unsigned)(uint32_t) st.st_mode,
	(unsigned)(uint32_t) st.st_uid,
	(unsigned)(uint32_t) st.st_gid,
	(unsigned)(uint32_t) st.st_nlink,
	(unsigned)(uint32_t) st.st_mtime,
	(unsigned)(uint32_t) st.st_size,
	(unsigned)(uint32_t) major(st.st_dev),
	(unsigned)(uint32_t) minor(st.st_dev),
	(unsigned)(uint32_t) major(st.st_rdev),
	(unsigned)(uint32_t) minor(st.st_rdev),
	(unsigned)(strlen(name) + 1),
	name, '\0');
	bytes = cpio_pad4(bytes);

	if (st.st_size) {
	if (S_ISLNK(st.st_mode)) {
	char *lpath = xmalloc_readlink_or_warn(name);
	if (!lpath)
	goto abort_cpio_o;
	bytes += printf("%s", lpath);
	free(lpath);
	} else { /* S_ISREG */
	int fd = xopen(name, O_RDONLY);
	fflush_all();
	/* We must abort if file got shorter too! */
	bb_copyfd_exact_size(fd, STDOUT_FILENO, st.st_size);
	bytes += st.st_size;
	close(fd);
	}
	bytes = cpio_pad4(bytes);
	}

	if (!line) {
	if (name != cpio_TRAILER)
	goto next_link;
	/* TODO: GNU cpio pads trailer to 512 bytes, do we want that? */
	return EXIT_SUCCESS;
	}

	free(line);
	} /* end of "while (1)" */
	}
	#endif

	int cpio_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int cpio_main(int argc UNUSED_PARAM, char **argv)
	{
	archive_handle_t *archive_handle;
	char *cpio_filename;
	char *cpio_owner;
	IF_FEATURE_CPIO_O(const char *cpio_fmt = "";)
	unsigned opt;
	#if ENABLE_LONG_OPTS
	const char *long_opts =
	"extract\0" No_argument "i"
	"list\0" No_argument "t"
	#if ENABLE_FEATURE_CPIO_O
	"create\0" No_argument "o"
	"format\0" Required_argument "H"
	#if ENABLE_FEATURE_CPIO_P
	"pass-through\0" No_argument "p"
	#endif
	#endif
	"owner\0" Required_argument "R"
	"verbose\0" No_argument "v"
	"null\0" No_argument "0"
	"quiet\0" No_argument "\xff"
	"to-stdout\0" No_argument "\xfe"
	;
	#endif

	INIT_G();
	archive_handle = init_handle();
	/* archive_handle->src_fd = STDIN_FILENO; - done by init_handle */
	archive_handle->ah_flags = ARCHIVE_EXTRACT_NEWER;

	/* As of now we do not enforce this: */
	/* -i,-t,-o,-p are mutually exclusive */
	/* -u,-d,-m make sense only with -i or -p */
	/* -L makes sense only with -o or -p */

	#if !ENABLE_FEATURE_CPIO_O
	opt = getopt32long(argv, OPTION_STR, long_opts, &cpio_filename, &cpio_owner);
	#else
	opt = getopt32long(argv, OPTION_STR "oH:" IF_FEATURE_CPIO_P("p"), long_opts,
	&cpio_filename, &cpio_owner, &cpio_fmt);
	#endif
	argv += optind;
	if (opt & OPT_OWNER) { /* -R */
	parse_chown_usergroup_or_die(&G.owner_ugid, cpio_owner);
	archive_handle->cpio__owner = G.owner_ugid;
	}
	#if !ENABLE_FEATURE_CPIO_O
	if (opt & OPT_FILE) { /* -F */
	xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
	}
	#else
	if ((opt & (OPT_FILE\|OPT_CREATE)) == OPT_FILE) { /* -F without -o */
	xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
	}
	if (opt & OPT_PASSTHROUGH) {
	pid_t pid;
	struct fd_pair pp;

	if (argv[0] == NULL)
	bb_show_usage();
	if (opt & OPT_CREATE_LEADING_DIR)
	mkdir(argv[0], 0777);
	/* Crude existence check:
	* close(xopen(argv[0], O_RDONLY \| O_DIRECTORY));
	* We can also xopen, fstat, IS_DIR, later fchdir.
	* This would check for existence earlier and cleaner.
	* As it stands now, if we fail xchdir later,
	* child dies on EPIPE, unless it caught
	* a diffrerent problem earlier.
	* This is good enough for now.
	*/
	#if !BB_MMU
	pp.rd = 3;
	pp.wr = 4;
	if (!re_execed) {
	close(3);
	close(4);
	xpiped_pair(pp);
	}
	#else
	xpiped_pair(pp);
	#endif
	pid = fork_or_rexec(argv - optind);
	if (pid == 0) { /* child */
	close(pp.rd);
	xmove_fd(pp.wr, STDOUT_FILENO);
	goto dump;
	}
	/* parent */
	USE_FOR_NOMMU(argv[-optind][0] &= 0x7f); /* undo fork_or_rexec() damage */
	xchdir(*argv++);
	close(pp.wr);
	xmove_fd(pp.rd, STDIN_FILENO);
	//opt &= ~OPT_PASSTHROUGH;
	opt \|= OPT_EXTRACT;
	goto skip;
	}
	/* -o */
	if (opt & OPT_CREATE) {
	if (cpio_fmt[0] != 'n') /* we _require_ "-H newc" */
	bb_show_usage();
	if (opt & OPT_FILE) {
	xmove_fd(xopen(cpio_filename, O_WRONLY \| O_CREAT \| O_TRUNC), STDOUT_FILENO);
	}
	dump:
	return cpio_o();
	}
	skip:
	#endif

	/* One of either extract or test options must be given */
	if ((opt & (OPT_TEST \| OPT_EXTRACT)) == 0) {
	bb_show_usage();
	}

	if (opt & OPT_TEST) {
	/* if both extract and test options are given, ignore extract option */
	opt &= ~OPT_EXTRACT;
	archive_handle->action_header = header_list;
	}
	if (opt & OPT_EXTRACT) {
	archive_handle->action_data = data_extract_all;
	if (opt & OPT_2STDOUT)
	archive_handle->action_data = data_extract_to_stdout;
	}
	if (opt & OPT_UNCONDITIONAL) {
	archive_handle->ah_flags \|= ARCHIVE_UNLINK_OLD;
	archive_handle->ah_flags &= ~ARCHIVE_EXTRACT_NEWER;
	}
	if (opt & OPT_VERBOSE) {
	if (archive_handle->action_header == header_list) {
	archive_handle->action_header = header_verbose_list;
	} else {
	archive_handle->action_header = header_list;
	}
	}
	if (opt & OPT_CREATE_LEADING_DIR) {
	archive_handle->ah_flags \|= ARCHIVE_CREATE_LEADING_DIRS;
	}
	if (opt & OPT_PRESERVE_MTIME) {
	archive_handle->ah_flags \|= ARCHIVE_RESTORE_DATE;
	}

	while (*argv) {
	archive_handle->filter = filter_accept_list;
	llist_add_to(&archive_handle->accept, *argv);
	argv++;
	}

	/* see get_header_cpio */
	archive_handle->cpio__blocks = (off_t)-1;
	while (get_header_cpio(archive_handle) == EXIT_SUCCESS)
	continue;

	create_links_from_list(archive_handle->link_placeholders);

	if (archive_handle->cpio__blocks != (off_t)-1
	&& !(opt & OPT_QUIET)
	) {
	fprintf(stderr, "%"OFF_FMT"u blocks\n", archive_handle->cpio__blocks);
	}

	return EXIT_SUCCESS;
	}