/* vi: set sw=4 ts=4: */
/*
 *  Common code for gunzip-like applets
 *
 *  Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include "unarchive.h"

enum {
        OPT_STDOUT = 0x1,
        OPT_FORCE = 0x2,
/* gunzip and bunzip2 only: */
        OPT_VERBOSE = 0x4,
        OPT_DECOMPRESS = 0x8,
        OPT_TEST = 0x10,
};

static
int open_to_or_warn(int to_fd, const char *filename, int flags, int mode)
{
        int fd = open3_or_warn(filename, flags, mode);
        if (fd < 0) {
                return 1;
        }
        xmove_fd(fd, to_fd);
        return 0;
}

int FAST_FUNC bbunpack(char **argv,
        char* (*make_new_name)(char *filename),
        IF_DESKTOP(long long) int (*unpacker)(unpack_info_t *info)
)
{
        struct stat stat_buf;
        IF_DESKTOP(long long) int status;
        char *filename, *new_name;
        smallint exitcode = 0;
        unpack_info_t info;

        do {
                /* NB: new_name is *maybe* malloc'ed! */
                new_name = NULL;
                filename = *argv; /* can be NULL - 'streaming' bunzip2 */

                if (filename && LONE_DASH(filename))
                        filename = NULL;

                /* Open src */
                if (filename) {
                        if (stat(filename, &stat_buf) != 0) {
                                bb_simple_perror_msg(filename);
 err:
                                exitcode = 1;
                                goto free_name;
                        }
                        if (open_to_or_warn(STDIN_FILENO, filename, O_RDONLY, 0))
                                goto err;
                }

                /* Special cases: test, stdout */
                if (option_mask32 & (OPT_STDOUT|OPT_TEST)) {
                        if (option_mask32 & OPT_TEST)
                                if (open_to_or_warn(STDOUT_FILENO, bb_dev_null, O_WRONLY, 0))
                                        goto err;
                        filename = NULL;
                }

                /* Open dst if we are going to unpack to file */
                if (filename) {
                        new_name = make_new_name(filename);
                        if (!new_name) {
                                bb_error_msg("%s: unknown suffix - ignored", filename);
                                goto err;
                        }

                        /* -f: overwrite existing output files */
                        if (option_mask32 & OPT_FORCE) {
                                unlink(new_name);
                        }

                        /* O_EXCL: "real" bunzip2 doesn't overwrite files */
                        /* GNU gunzip does not bail out, but goes to next file */
                        if (open_to_or_warn(STDOUT_FILENO, new_name, O_WRONLY | O_CREAT | O_EXCL,
                                        stat_buf.st_mode))
                                goto err;
                }

                /* Check that the input is sane */
                if (isatty(STDIN_FILENO) && (option_mask32 & OPT_FORCE) == 0) {
                        bb_error_msg_and_die("compressed data not read from terminal, "
                                        "use -f to force it");
                }

                /* memset(&info, 0, sizeof(info)); */
                info.mtime = 0; /* so far it has one member only */
                status = unpacker(&info);
                if (status < 0)
                        exitcode = 1;

                if (filename) {
                        char *del = new_name;
                        if (status >= 0) {
                                /* TODO: restore other things? */
                                if (info.mtime) {
                                        struct utimbuf times;

                                        times.actime = info.mtime;
                                        times.modtime = info.mtime;
                                        /* Close first.
                                         * On some systems calling utime
                                         * then closing resets the mtime. */
                                        close(STDOUT_FILENO);
                                        /* Ignoring errors */
                                        utime(new_name, &times);
                                }

                                /* Delete _compressed_ file */
                                del = filename;
                                /* restore extension (unless tgz -> tar case) */
                                if (new_name == filename)
                                        filename[strlen(filename)] = '.';
                        }
                        xunlink(del);

#if 0 /* Currently buggy - wrong name: "a.gz: 261% - replaced with a.gz" */
                        /* Extreme bloat for gunzip compat */
                        if (ENABLE_DESKTOP && (option_mask32 & OPT_VERBOSE) && status >= 0) {
                                fprintf(stderr, "%s: %u%% - replaced with %s\n",
                                        filename, (unsigned)(stat_buf.st_size*100 / (status+1)), new_name);
                        }
#endif

 free_name:
                        if (new_name != filename)
                                free(new_name);
                }
        } while (*argv && *++argv);

        return exitcode;
}

#if ENABLE_BUNZIP2 || ENABLE_UNLZMA || ENABLE_UNCOMPRESS

static
char* make_new_name_generic(char *filename, const char *expected_ext)
{
        char *extension = strrchr(filename, '.');
        if (!extension || strcmp(extension + 1, expected_ext) != 0) {
                /* Mimic GNU gunzip - "real" bunzip2 tries to */
                /* unpack file anyway, to file.out */
                return NULL;
        }
        *extension = '\0';
        return filename;
}

#endif


/*
 *  Modified for busybox by Glenn McGrath
 *  Added support output to stdout by Thomas Lundquist <thomasez@zelow.no>
 *
 *  Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#if ENABLE_BUNZIP2

static
char* make_new_name_bunzip2(char *filename)
{
        return make_new_name_generic(filename, "bz2");
}

static
IF_DESKTOP(long long) int unpack_bunzip2(unpack_info_t *info UNUSED_PARAM)
{
        return unpack_bz2_stream_prime(STDIN_FILENO, STDOUT_FILENO);
}

int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int bunzip2_main(int argc UNUSED_PARAM, char **argv)
{
        getopt32(argv, "cfvdt");
        argv += optind;
        if (applet_name[2] == 'c')
                option_mask32 |= OPT_STDOUT;

        return bbunpack(argv, make_new_name_bunzip2, unpack_bunzip2);
}

#endif


/*
 * Gzip implementation for busybox
 *
 * Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
 *
 * Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
 * based on gzip sources
 *
 * Adjusted further by Erik Andersen <andersen@codepoet.org> to support files as
 * well as stdin/stdout, and to generally behave itself wrt command line
 * handling.
 *
 * General cleanup to better adhere to the style guide and make use of standard
 * busybox functions by Glenn McGrath
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * The unzip code was written and put in the public domain by Mark Adler.
 * Portions of the lzw code are derived from the public domain 'compress'
 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
 * Ken Turkowski, Dave Mack and Peter Jannesen.
 *
 * See the license_msg below and the file COPYING for the software license.
 * See the file algorithm.doc for the compression algorithms and file formats.
 */

#if ENABLE_GUNZIP

static
char* make_new_name_gunzip(char *filename)
{
        char *extension = strrchr(filename, '.');

        if (!extension)
                return NULL;

        extension++;
        if (strcmp(extension, "tgz" + 1) == 0
#if ENABLE_FEATURE_SEAMLESS_Z
         || (extension[0] == 'Z' && extension[1] == '\0')
#endif
        ) {
                extension[-1] = '\0';
        } else if (strcmp(extension, "tgz") == 0) {
                filename = xstrdup(filename);
                extension = strrchr(filename, '.');
                extension[2] = 'a';
                extension[3] = 'r';
        } else {
                return NULL;
        }
        return filename;
}

static
IF_DESKTOP(long long) int unpack_gunzip(unpack_info_t *info)
{
        IF_DESKTOP(long long) int status = -1;

        /* do the decompression, and cleanup */
        if (xread_char(STDIN_FILENO) == 0x1f) {
                unsigned char magic2;

                magic2 = xread_char(STDIN_FILENO);
                if (ENABLE_FEATURE_SEAMLESS_Z && magic2 == 0x9d) {
                        status = unpack_Z_stream(STDIN_FILENO, STDOUT_FILENO);
                } else if (magic2 == 0x8b) {
                        status = unpack_gz_stream_with_info(STDIN_FILENO, STDOUT_FILENO, info);
                } else {
                        goto bad_magic;
                }
                if (status < 0) {
                        bb_error_msg("error inflating");
                }
        } else {
 bad_magic:
                bb_error_msg("invalid magic");
                /* status is still == -1 */
        }
        return status;
}

/*
 * Linux kernel build uses gzip -d -n. We accept and ignore it.
 * Man page says:
 * -n --no-name
 * gzip: do not save the original file name and time stamp.
 * (The original name is always saved if the name had to be truncated.)
 * gunzip: do not restore the original file name/time even if present
 * (remove only the gzip suffix from the compressed file name).
 * This option is the default when decompressing.
 * -N --name
 * gzip: always save the original file name and time stamp (this is the default)
 * gunzip: restore the original file name and time stamp if present.
 */

int gunzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int gunzip_main(int argc UNUSED_PARAM, char **argv)
{
        getopt32(argv, "cfvdtn");
        argv += optind;
        /* if called as zcat */
        if (applet_name[1] == 'c')
                option_mask32 |= OPT_STDOUT;

        return bbunpack(argv, make_new_name_gunzip, unpack_gunzip);
}

#endif


/*
 * Small lzma deflate implementation.
 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
 *
 * Based on bunzip.c from busybox
 *
 * Licensed under GPL v2, see file LICENSE in this tarball for details.
 */

#if ENABLE_UNLZMA

static
char* make_new_name_unlzma(char *filename)
{
        return make_new_name_generic(filename, "lzma");
}

static
IF_DESKTOP(long long) int unpack_unlzma(unpack_info_t *info UNUSED_PARAM)
{
        return unpack_lzma_stream(STDIN_FILENO, STDOUT_FILENO);
}

int unlzma_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unlzma_main(int argc UNUSED_PARAM, char **argv)
{
        getopt32(argv, "cf");
        argv += optind;
        /* lzmacat? */
        if (applet_name[4] == 'c')
                option_mask32 |= OPT_STDOUT;

        return bbunpack(argv, make_new_name_unlzma, unpack_unlzma);
}

#endif


/*
 *      Uncompress applet for busybox (c) 2002 Glenn McGrath
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#if ENABLE_UNCOMPRESS

static
char* make_new_name_uncompress(char *filename)
{
        return make_new_name_generic(filename, "Z");
}

static
IF_DESKTOP(long long) int unpack_uncompress(unpack_info_t *info UNUSED_PARAM)
{
        IF_DESKTOP(long long) int status = -1;

        if ((xread_char(STDIN_FILENO) != 0x1f) || (xread_char(STDIN_FILENO) != 0x9d)) {
                bb_error_msg("invalid magic");
        } else {
                status = unpack_Z_stream(STDIN_FILENO, STDOUT_FILENO);
        }
        return status;
}

int uncompress_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int uncompress_main(int argc UNUSED_PARAM, char **argv)
{
        getopt32(argv, "cf");
        argv += optind;

        return bbunpack(argv, make_new_name_uncompress, unpack_uncompress);
}

#endif