/* 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
 *
 */
#include "libbb.h"
#include "archive.h"

//usage:#define cpio_trivial_usage
//usage:       "[-dmvu] [-F FILE]" 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 or list files from a cpio archive"
//usage:        IF_FEATURE_CPIO_O(", or"
//usage:     "\ncreate an archive" IF_FEATURE_CPIO_P(" (-o) or copy files (-p)")
//usage:                " using file list on stdin"
//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:     "\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:        IF_FEATURE_CPIO_O(
//usage:     "\n        -H newc Archive format"
//usage:        )

/* 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][:.][GROUP] 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
 */

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),
        OPTBIT_FILE = 8,
        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:"

#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)
{
        static const char trailer[] ALIGN1 = "TRAILER!!!";
        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 (!(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 = 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 != 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;
        IF_FEATURE_CPIO_O(const char *cpio_fmt = "";)
        unsigned opt;

#if ENABLE_LONG_OPTS
        applet_long_options =
                "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
                "verbose\0"      No_argument       "v"
                "quiet\0"        No_argument       "\xff"
                "to-stdout\0"    No_argument       "\xfe"
                ;
#endif

        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 = getopt32(argv, OPTION_STR, &cpio_filename);
        argv += optind;
        if (opt & OPT_FILE) { /* -F */
                xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
        }
#else
        opt = getopt32(argv, OPTION_STR "oH:" IF_FEATURE_CPIO_P("p"), &cpio_filename, &cpio_fmt);
        argv += optind;
        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 */
                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;

        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;
}