source: MondoRescue/branches/3.3/mindi-busybox/archival/tar.c

/* vi: set sw=4 ts=4: */
/*
 * Mini tar implementation for busybox
 *
 * Modified to use common extraction code used by ar, cpio, dpkg-deb, dpkg
 *  by Glenn McGrath
 *
 * Note, that as of BusyBox-0.43, tar has been completely rewritten from the
 * ground up.  It still has remnants of the old code lying about, but it is
 * very different now (i.e., cleaner, less global variables, etc.)
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Based in part in the tar implementation in sash
 *  Copyright (c) 1999 by David I. Bell
 *  Permission is granted to use, distribute, or modify this source,
 *  provided that this copyright notice remains intact.
 *  Permission to distribute sash derived code under GPL has been granted.
 *
 * Based in part on the tar implementation from busybox-0.28
 *  Copyright (C) 1995 Bruce Perens
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/* TODO: security with -C DESTDIR option can be enhanced.
 * Consider tar file created via:
 * $ tar cvf bug.tar anything.txt
 * $ ln -s /tmp symlink
 * $ tar --append -f bug.tar symlink
 * $ rm symlink
 * $ mkdir symlink
 * $ tar --append -f bug.tar symlink/evil.py
 *
 * This will result in an archive which contains:
 * $ tar --list -f bug.tar
 * anything.txt
 * symlink
 * symlink/evil.py
 *
 * Untarring it puts evil.py in '/tmp' even if the -C DESTDIR is given.
 * This doesn't feel right, and IIRC GNU tar doesn't do that.
 */

//config:config TAR
//config:   bool "tar"
//config:   default y
//config:   help
//config:     tar is an archiving program. It's commonly used with gzip to
//config:     create compressed archives. It's probably the most widely used
//config:     UNIX archive program.
//config:
//config:config FEATURE_TAR_CREATE
//config:   bool "Enable archive creation"
//config:   default y
//config:   depends on TAR
//config:   help
//config:     If you enable this option you'll be able to create
//config:     tar archives using the `-c' option.
//config:
//config:config FEATURE_TAR_AUTODETECT
//config:   bool "Autodetect compressed tarballs"
//config:   default y
//config:   depends on TAR && (FEATURE_SEAMLESS_Z || FEATURE_SEAMLESS_GZ || FEATURE_SEAMLESS_BZ2 || FEATURE_SEAMLESS_LZMA || FEATURE_SEAMLESS_XZ)
//config:   help
//config:     With this option tar can automatically detect compressed
//config:     tarballs. Currently it works only on files (not pipes etc).
//config:
//config:config FEATURE_TAR_FROM
//config:   bool "Enable -X (exclude from) and -T (include from) options)"
//config:   default y
//config:   depends on TAR
//config:   help
//config:     If you enable this option you'll be able to specify
//config:     a list of files to include or exclude from an archive.
//config:
//config:config FEATURE_TAR_OLDGNU_COMPATIBILITY
//config:   bool "Support for old tar header format"
//config:   default y
//config:   depends on TAR || DPKG
//config:   help
//config:     This option is required to unpack archives created in
//config:     the old GNU format; help to kill this old format by
//config:     repacking your ancient archives with the new format.
//config:
//config:config FEATURE_TAR_OLDSUN_COMPATIBILITY
//config:   bool "Enable untarring of tarballs with checksums produced by buggy Sun tar"
//config:   default y
//config:   depends on TAR || DPKG
//config:   help
//config:     This option is required to unpack archives created by some old
//config:     version of Sun's tar (it was calculating checksum using signed
//config:     arithmetic). It is said to be fixed in newer Sun tar, but "old"
//config:     tarballs still exist.
//config:
//config:config FEATURE_TAR_GNU_EXTENSIONS
//config:   bool "Support for GNU tar extensions (long filenames)"
//config:   default y
//config:   depends on TAR || DPKG
//config:   help
//config:     With this option busybox supports GNU long filenames and
//config:     linknames.
//config:
//config:config FEATURE_TAR_LONG_OPTIONS
//config:   bool "Enable long options"
//config:   default y
//config:   depends on TAR && LONG_OPTS
//config:   help
//config:     Enable use of long options, increases size by about 400 Bytes
//config:
//config:config FEATURE_TAR_TO_COMMAND
//config:   bool "Support for writing to an external program"
//config:   default y
//config:   depends on TAR && FEATURE_TAR_LONG_OPTIONS
//config:   help
//config:     If you enable this option you'll be able to instruct tar to send
//config:     the contents of each extracted file to the standard input of an
//config:     external program.
//config:
//config:config FEATURE_TAR_UNAME_GNAME
//config:   bool "Enable use of user and group names"
//config:   default y
//config:   depends on TAR
//config:   help
//config:     Enables use of user and group names in tar. This affects contents
//config:     listings (-t) and preserving permissions when unpacking (-p).
//config:     +200 bytes.
//config:
//config:config FEATURE_TAR_NOPRESERVE_TIME
//config:   bool "Enable -m (do not preserve time) option"
//config:   default y
//config:   depends on TAR
//config:   help
//config:     With this option busybox supports GNU tar -m
//config:     (do not preserve time) option.
//config:
//config:config FEATURE_TAR_SELINUX
//config:   bool "Support for extracting SELinux labels"
//config:   default n
//config:   depends on TAR && SELINUX
//config:   help
//config:     With this option busybox supports restoring SELinux labels
//config:     when extracting files from tar archives.

//applet:IF_TAR(APPLET(tar, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_TAR) += tar.o

#include <fnmatch.h>
#include "libbb.h"
#include "common_bufsiz.h"
#include "bb_archive.h"
/* FIXME: Stop using this non-standard feature */
#ifndef FNM_LEADING_DIR
# define FNM_LEADING_DIR 0
#endif

#if 0
# define DBG(fmt, ...) bb_error_msg("%s: " fmt, __func__, ## __VA_ARGS__)
#else
# define DBG(...) ((void)0)
#endif
#define DBG_OPTION_PARSING 0


#define block_buf bb_common_bufsiz1
#define INIT_G() do { setup_common_bufsiz(); } while (0)


#if ENABLE_FEATURE_TAR_CREATE

/*
** writeTarFile(), writeFileToTarball(), and writeTarHeader() are
** the only functions that deal with the HardLinkInfo structure.
** Even these functions use the xxxHardLinkInfo() functions.
*/
typedef struct HardLinkInfo {
    struct HardLinkInfo *next; /* Next entry in list */
    dev_t dev;                 /* Device number */
    ino_t ino;                 /* Inode number */
//  short linkCount;           /* (Hard) Link Count */
    char name[1];              /* Start of filename (must be last) */
} HardLinkInfo;

/* Some info to be carried along when creating a new tarball */
typedef struct TarBallInfo {
    int tarFd;                      /* Open-for-write file descriptor
                                     * for the tarball */
    int verboseFlag;                /* Whether to print extra stuff or not */
    const llist_t *excludeList;     /* List of files to not include */
    HardLinkInfo *hlInfoHead;       /* Hard Link Tracking Information */
    HardLinkInfo *hlInfo;           /* Hard Link Info for the current file */
//TODO: save only st_dev + st_ino
    struct stat tarFileStatBuf;     /* Stat info for the tarball, letting
                                     * us know the inode and device that the
                                     * tarball lives, so we can avoid trying
                                     * to include the tarball into itself */
} TarBallInfo;

/* A nice enum with all the possible tar file content types */
enum {
    REGTYPE = '0',      /* regular file */
    REGTYPE0 = '\0',    /* regular file (ancient bug compat) */
    LNKTYPE = '1',      /* hard link */
    SYMTYPE = '2',      /* symbolic link */
    CHRTYPE = '3',      /* character special */
    BLKTYPE = '4',      /* block special */
    DIRTYPE = '5',      /* directory */
    FIFOTYPE = '6',     /* FIFO special */
    CONTTYPE = '7',     /* reserved */
    GNULONGLINK = 'K',  /* GNU long (>100 chars) link name */
    GNULONGNAME = 'L',  /* GNU long (>100 chars) file name */
};

/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
static void addHardLinkInfo(HardLinkInfo **hlInfoHeadPtr,
                    struct stat *statbuf,
                    const char *fileName)
{
    /* Note: hlInfoHeadPtr can never be NULL! */
    HardLinkInfo *hlInfo;

    hlInfo = xmalloc(sizeof(HardLinkInfo) + strlen(fileName));
    hlInfo->next = *hlInfoHeadPtr;
    *hlInfoHeadPtr = hlInfo;
    hlInfo->dev = statbuf->st_dev;
    hlInfo->ino = statbuf->st_ino;
//  hlInfo->linkCount = statbuf->st_nlink;
    strcpy(hlInfo->name, fileName);
}

static void freeHardLinkInfo(HardLinkInfo **hlInfoHeadPtr)
{
    HardLinkInfo *hlInfo;
    HardLinkInfo *hlInfoNext;

    if (hlInfoHeadPtr) {
        hlInfo = *hlInfoHeadPtr;
        while (hlInfo) {
            hlInfoNext = hlInfo->next;
            free(hlInfo);
            hlInfo = hlInfoNext;
        }
        *hlInfoHeadPtr = NULL;
    }
}

/* Might be faster (and bigger) if the dev/ino were stored in numeric order ;) */
static HardLinkInfo *findHardLinkInfo(HardLinkInfo *hlInfo, struct stat *statbuf)
{
    while (hlInfo) {
        if (statbuf->st_ino == hlInfo->ino
         && statbuf->st_dev == hlInfo->dev
        ) {
            DBG("found hardlink:'%s'", hlInfo->name);
            break;
        }
        hlInfo = hlInfo->next;
    }
    return hlInfo;
}

/* Put an octal string into the specified buffer.
 * The number is zero padded and possibly null terminated.
 * Stores low-order bits only if whole value does not fit. */
static void putOctal(char *cp, int len, off_t value)
{
    char tempBuffer[sizeof(off_t)*3 + 1];
    char *tempString = tempBuffer;
    int width;

    width = sprintf(tempBuffer, "%0*"OFF_FMT"o", len, value);
    tempString += (width - len);

    /* If string has leading zeroes, we can drop one */
    /* and field will have trailing '\0' */
    /* (increases chances of compat with other tars) */
    if (tempString[0] == '0')
        tempString++;

    /* Copy the string to the field */
    memcpy(cp, tempString, len);
}
#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))

static void chksum_and_xwrite(int fd, struct tar_header_t* hp)
{
    /* POSIX says that checksum is done on unsigned bytes
     * (Sun and HP-UX gets it wrong... more details in
     * GNU tar source) */
    const unsigned char *cp;
    int chksum, size;

    strcpy(hp->magic, "ustar  ");

    /* Calculate and store the checksum (i.e., the sum of all of the bytes of
     * the header).  The checksum field must be filled with blanks for the
     * calculation.  The checksum field is formatted differently from the
     * other fields: it has 6 digits, a null, then a space -- rather than
     * digits, followed by a null like the other fields... */
    memset(hp->chksum, ' ', sizeof(hp->chksum));
    cp = (const unsigned char *) hp;
    chksum = 0;
    size = sizeof(*hp);
    do { chksum += *cp++; } while (--size);
    putOctal(hp->chksum, sizeof(hp->chksum)-1, chksum);

    /* Now write the header out to disk */
    xwrite(fd, hp, sizeof(*hp));
}

#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
static void writeLongname(int fd, int type, const char *name, int dir)
{
    static const struct {
        char mode[8];             /* 100-107 */
        char uid[8];              /* 108-115 */
        char gid[8];              /* 116-123 */
        char size[12];            /* 124-135 */
        char mtime[12];           /* 136-147 */
    } prefilled = {
        "0000000",
        "0000000",
        "0000000",
        "00000000000",
        "00000000000",
    };
    struct tar_header_t header;
    int size;

    dir = !!dir; /* normalize: 0/1 */
    size = strlen(name) + 1 + dir; /* GNU tar uses strlen+1 */
    /* + dir: account for possible '/' */

    memset(&header, 0, sizeof(header));
    strcpy(header.name, "././@LongLink");
    memcpy(header.mode, prefilled.mode, sizeof(prefilled));
    PUT_OCTAL(header.size, size);
    header.typeflag = type;
    chksum_and_xwrite(fd, &header);

    /* Write filename[/] and pad the block. */
    /* dir=0: writes 'name<NUL>', pads */
    /* dir=1: writes 'name', writes '/<NUL>', pads */
    dir *= 2;
    xwrite(fd, name, size - dir);
    xwrite(fd, "/", dir);
    size = (-size) & (TAR_BLOCK_SIZE-1);
    memset(&header, 0, size);
    xwrite(fd, &header, size);
}
#endif

/* Write out a tar header for the specified file/directory/whatever */
static int writeTarHeader(struct TarBallInfo *tbInfo,
        const char *header_name, const char *fileName, struct stat *statbuf)
{
    struct tar_header_t header;

    memset(&header, 0, sizeof(header));

    strncpy(header.name, header_name, sizeof(header.name));

    /* POSIX says to mask mode with 07777. */
    PUT_OCTAL(header.mode, statbuf->st_mode & 07777);
    PUT_OCTAL(header.uid, statbuf->st_uid);
    PUT_OCTAL(header.gid, statbuf->st_gid);
    memset(header.size, '0', sizeof(header.size)-1); /* Regular file size is handled later */
    /* users report that files with negative st_mtime cause trouble, so: */
    PUT_OCTAL(header.mtime, statbuf->st_mtime >= 0 ? statbuf->st_mtime : 0);

    /* Enter the user and group names */
    safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
    safe_strncpy(header.gname, get_cached_groupname(statbuf->st_gid), sizeof(header.gname));

    if (tbInfo->hlInfo) {
        /* This is a hard link */
        header.typeflag = LNKTYPE;
        strncpy(header.linkname, tbInfo->hlInfo->name,
                sizeof(header.linkname));
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
        /* Write out long linkname if needed */
        if (header.linkname[sizeof(header.linkname)-1])
            writeLongname(tbInfo->tarFd, GNULONGLINK,
                    tbInfo->hlInfo->name, 0);
#endif
    } else if (S_ISLNK(statbuf->st_mode)) {
        char *lpath = xmalloc_readlink_or_warn(fileName);
        if (!lpath)
            return FALSE;
        header.typeflag = SYMTYPE;
        strncpy(header.linkname, lpath, sizeof(header.linkname));
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
        /* Write out long linkname if needed */
        if (header.linkname[sizeof(header.linkname)-1])
            writeLongname(tbInfo->tarFd, GNULONGLINK, lpath, 0);
#else
        /* If it is larger than 100 bytes, bail out */
        if (header.linkname[sizeof(header.linkname)-1]) {
            free(lpath);
            bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
            return FALSE;
        }
#endif
        free(lpath);
    } else if (S_ISDIR(statbuf->st_mode)) {
        header.typeflag = DIRTYPE;
        /* Append '/' only if there is a space for it */
        if (!header.name[sizeof(header.name)-1])
            header.name[strlen(header.name)] = '/';
    } else if (S_ISCHR(statbuf->st_mode)) {
        header.typeflag = CHRTYPE;
        PUT_OCTAL(header.devmajor, major(statbuf->st_rdev));
        PUT_OCTAL(header.devminor, minor(statbuf->st_rdev));
    } else if (S_ISBLK(statbuf->st_mode)) {
        header.typeflag = BLKTYPE;
        PUT_OCTAL(header.devmajor, major(statbuf->st_rdev));
        PUT_OCTAL(header.devminor, minor(statbuf->st_rdev));
    } else if (S_ISFIFO(statbuf->st_mode)) {
        header.typeflag = FIFOTYPE;
    } else if (S_ISREG(statbuf->st_mode)) {
        /* header.size field is 12 bytes long */
        /* Does octal-encoded size fit? */
        uoff_t filesize = statbuf->st_size;
        if (sizeof(filesize) <= 4
         || filesize <= (uoff_t)0777777777777LL
        ) {
            PUT_OCTAL(header.size, filesize);
        }
        /* Does base256-encoded size fit?
         * It always does unless off_t is wider than 64 bits.
         */
        else if (ENABLE_FEATURE_TAR_GNU_EXTENSIONS
#if ULLONG_MAX > 0xffffffffffffffffLL /* 2^64-1 */
         && (filesize <= 0x3fffffffffffffffffffffffLL)
#endif
        ) {
            /* GNU tar uses "base-256 encoding" for very large numbers.
             * Encoding is binary, with highest bit always set as a marker
             * and sign in next-highest bit:
             * 80 00 .. 00 - zero
             * bf ff .. ff - largest positive number
             * ff ff .. ff - minus 1
             * c0 00 .. 00 - smallest negative number
             */
            char *p8 = header.size + sizeof(header.size);
            do {
                *--p8 = (uint8_t)filesize;
                filesize >>= 8;
            } while (p8 != header.size);
            *p8 |= 0x80;
        } else {
            bb_error_msg_and_die("can't store file '%s' "
                "of size %"OFF_FMT"u, aborting",
                fileName, statbuf->st_size);
        }
        header.typeflag = REGTYPE;
    } else {
        bb_error_msg("%s: unknown file type", fileName);
        return FALSE;
    }

#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
    /* Write out long name if needed */
    /* (we, like GNU tar, output long linkname *before* long name) */
    if (header.name[sizeof(header.name)-1])
        writeLongname(tbInfo->tarFd, GNULONGNAME,
                header_name, S_ISDIR(statbuf->st_mode));
#endif

    /* Now write the header out to disk */
    chksum_and_xwrite(tbInfo->tarFd, &header);

    /* Now do the verbose thing (or not) */
    if (tbInfo->verboseFlag) {
        FILE *vbFd = stdout;

        /* If archive goes to stdout, verbose goes to stderr */
        if (tbInfo->tarFd == STDOUT_FILENO)
            vbFd = stderr;
        /* GNU "tar cvvf" prints "extended" listing a-la "ls -l" */
        /* We don't have such excesses here: for us "v" == "vv" */
        /* '/' is probably a GNUism */
        fprintf(vbFd, "%s%s\n", header_name,
                S_ISDIR(statbuf->st_mode) ? "/" : "");
    }

    return TRUE;
}

#if ENABLE_FEATURE_TAR_FROM
static int exclude_file(const llist_t *excluded_files, const char *file)
{
    while (excluded_files) {
        if (excluded_files->data[0] == '/') {
            if (fnmatch(excluded_files->data, file,
                    FNM_PATHNAME | FNM_LEADING_DIR) == 0)
                return 1;
        } else {
            const char *p;

            for (p = file; p[0] != '\0'; p++) {
                if ((p == file || p[-1] == '/')
                 && p[0] != '/'
                 && fnmatch(excluded_files->data, p,
                        FNM_PATHNAME | FNM_LEADING_DIR) == 0
                ) {
                    return 1;
                }
            }
        }
        excluded_files = excluded_files->link;
    }

    return 0;
}
#else
# define exclude_file(excluded_files, file) 0
#endif

static int FAST_FUNC writeFileToTarball(const char *fileName, struct stat *statbuf,
            void *userData, int depth UNUSED_PARAM)
{
    struct TarBallInfo *tbInfo = (struct TarBallInfo *) userData;
    const char *header_name;
    int inputFileFd = -1;

    DBG("writeFileToTarball('%s')", fileName);

    /* Strip leading '/' and such (must be before memorizing hardlink's name) */
    header_name = strip_unsafe_prefix(fileName);

    if (header_name[0] == '\0')
        return TRUE;

    /* It is against the rules to archive a socket */
    if (S_ISSOCK(statbuf->st_mode)) {
        bb_error_msg("%s: socket ignored", fileName);
        return TRUE;
    }

    /*
     * Check to see if we are dealing with a hard link.
     * If so -
     * Treat the first occurance of a given dev/inode as a file while
     * treating any additional occurances as hard links.  This is done
     * by adding the file information to the HardLinkInfo linked list.
     */
    tbInfo->hlInfo = NULL;
    if (!S_ISDIR(statbuf->st_mode) && statbuf->st_nlink > 1) {
        DBG("'%s': st_nlink > 1", header_name);
        tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf);
        if (tbInfo->hlInfo == NULL) {
            DBG("'%s': addHardLinkInfo", header_name);
            addHardLinkInfo(&tbInfo->hlInfoHead, statbuf, header_name);
        }
    }

    /* It is a bad idea to store the archive we are in the process of creating,
     * so check the device and inode to be sure that this particular file isn't
     * the new tarball */
    if (tbInfo->tarFileStatBuf.st_dev == statbuf->st_dev
     && tbInfo->tarFileStatBuf.st_ino == statbuf->st_ino
    ) {
        bb_error_msg("%s: file is the archive; skipping", fileName);
        return TRUE;
    }

    if (exclude_file(tbInfo->excludeList, header_name))
        return SKIP;

#if !ENABLE_FEATURE_TAR_GNU_EXTENSIONS
    if (strlen(header_name) >= NAME_SIZE) {
        bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
        return TRUE;
    }
#endif

    /* Is this a regular file? */
    if (tbInfo->hlInfo == NULL && S_ISREG(statbuf->st_mode)) {
        /* open the file we want to archive, and make sure all is well */
        inputFileFd = open_or_warn(fileName, O_RDONLY);
        if (inputFileFd < 0) {
            return FALSE;
        }
    }

    /* Add an entry to the tarball */
    if (writeTarHeader(tbInfo, header_name, fileName, statbuf) == FALSE) {
        return FALSE;
    }

    /* If it was a regular file, write out the body */
    if (inputFileFd >= 0) {
        size_t readSize;
        /* Write the file to the archive. */
        /* We record size into header first, */
        /* and then write out file. If file shrinks in between, */
        /* tar will be corrupted. So we don't allow for that. */
        /* NB: GNU tar 1.16 warns and pads with zeroes */
        /* or even seeks back and updates header */
        bb_copyfd_exact_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
        ////off_t readSize;
        ////readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
        ////if (readSize != statbuf->st_size && readSize >= 0) {
        ////    bb_error_msg_and_die("short read from %s, aborting", fileName);
        ////}

        /* Check that file did not grow in between? */
        /* if (safe_read(inputFileFd, 1) == 1) warn but continue? */

        close(inputFileFd);

        /* Pad the file up to the tar block size */
        /* (a few tricks here in the name of code size) */
        readSize = (-(int)statbuf->st_size) & (TAR_BLOCK_SIZE-1);
        memset(block_buf, 0, readSize);
        xwrite(tbInfo->tarFd, block_buf, readSize);
    }

    return TRUE;
}

#if SEAMLESS_COMPRESSION
/* Don't inline: vfork scares gcc and pessimizes code */
static void NOINLINE vfork_compressor(int tar_fd, const char *gzip)
{
    pid_t gzipPid;

    // On Linux, vfork never unpauses parent early, although standard
    // allows for that. Do we want to waste bytes checking for it?
# define WAIT_FOR_CHILD 0
    volatile int vfork_exec_errno = 0;
    struct fd_pair gzipDataPipe;
# if WAIT_FOR_CHILD
    struct fd_pair gzipStatusPipe;
    xpiped_pair(gzipStatusPipe);
# endif
    xpiped_pair(gzipDataPipe);

    signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */

    gzipPid = xvfork();

    if (gzipPid == 0) {
        /* child */
        /* NB: close _first_, then move fds! */
        close(gzipDataPipe.wr);
# if WAIT_FOR_CHILD
        close(gzipStatusPipe.rd);
        /* gzipStatusPipe.wr will close only on exec -
         * parent waits for this close to happen */
        fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
# endif
        xmove_fd(gzipDataPipe.rd, 0);
        xmove_fd(tar_fd, 1);
        /* exec gzip/bzip2 program/applet */
        BB_EXECLP(gzip, gzip, "-f", (char *)0);
        vfork_exec_errno = errno;
        _exit(EXIT_FAILURE);
    }

    /* parent */
    xmove_fd(gzipDataPipe.wr, tar_fd);
    close(gzipDataPipe.rd);
# if WAIT_FOR_CHILD
    close(gzipStatusPipe.wr);
    while (1) {
        char buf;
        int n;

        /* Wait until child execs (or fails to) */
        n = full_read(gzipStatusPipe.rd, &buf, 1);
        if (n < 0 /* && errno == EAGAIN */)
            continue;   /* try it again */
    }
    close(gzipStatusPipe.rd);
# endif
    if (vfork_exec_errno) {
        errno = vfork_exec_errno;
        bb_perror_msg_and_die("can't execute '%s'", gzip);
    }
}
#endif /* SEAMLESS_COMPRESSION */


#if !SEAMLESS_COMPRESSION
/* Do not pass gzip flag to writeTarFile() */
#define writeTarFile(tar_fd, verboseFlag, recurseFlags, include, exclude, gzip) \
    writeTarFile(tar_fd, verboseFlag, recurseFlags, include, exclude)
#endif
/* gcc 4.2.1 inlines it, making code bigger */
static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
    int recurseFlags, const llist_t *include,
    const llist_t *exclude, const char *gzip)
{
    int errorFlag = FALSE;
    struct TarBallInfo tbInfo;

    tbInfo.hlInfoHead = NULL;
    tbInfo.tarFd = tar_fd;
    tbInfo.verboseFlag = verboseFlag;

    /* Store the stat info for the tarball's file, so
     * can avoid including the tarball into itself....  */
    xfstat(tbInfo.tarFd, &tbInfo.tarFileStatBuf, "can't stat tar file");

#if SEAMLESS_COMPRESSION
    if (gzip)
        vfork_compressor(tbInfo.tarFd, gzip);
#endif

    tbInfo.excludeList = exclude;

    /* Read the directory/files and iterate over them one at a time */
    while (include) {
        if (!recursive_action(include->data, recurseFlags,
                writeFileToTarball, writeFileToTarball, &tbInfo, 0)
        ) {
            errorFlag = TRUE;
        }
        include = include->link;
    }
    /* Write two empty blocks to the end of the archive */
    memset(block_buf, 0, 2*TAR_BLOCK_SIZE);
    xwrite(tbInfo.tarFd, block_buf, 2*TAR_BLOCK_SIZE);

    /* To be pedantically correct, we would check if the tarball
     * is smaller than 20 tar blocks, and pad it if it was smaller,
     * but that isn't necessary for GNU tar interoperability, and
     * so is considered a waste of space */

    /* Close so the child process (if any) will exit */
    close(tbInfo.tarFd);

    /* Hang up the tools, close up shop, head home */
    if (ENABLE_FEATURE_CLEAN_UP)
        freeHardLinkInfo(&tbInfo.hlInfoHead);

    if (errorFlag)
        bb_error_msg("error exit delayed from previous errors");

#if SEAMLESS_COMPRESSION
    if (gzip) {
        int status;
        if (safe_waitpid(-1, &status, 0) == -1)
            bb_perror_msg("waitpid");
        else if (!WIFEXITED(status) || WEXITSTATUS(status))
            /* gzip was killed or has exited with nonzero! */
            errorFlag = TRUE;
    }
#endif
    return errorFlag;
}
#else /* !FEATURE_TAR_CREATE */
# define writeTarFile(...) 0
#endif

#if ENABLE_FEATURE_TAR_FROM
static llist_t *append_file_list_to_list(llist_t *list)
{
    FILE *src_stream;
    char *line;
    llist_t *newlist = NULL;

    while (list) {
        src_stream = xfopen_stdin(llist_pop(&list));
        while ((line = xmalloc_fgetline(src_stream)) != NULL) {
            /* kill trailing '/' unless the string is just "/" */
            char *cp = last_char_is(line, '/');
            if (cp > line)
                *cp = '\0';
            llist_add_to_end(&newlist, line);
        }
        fclose(src_stream);
    }
    return newlist;
}
#endif

//usage:#define tar_trivial_usage
//usage:    "-[" IF_FEATURE_TAR_CREATE("c") "xt"
//usage:    IF_FEATURE_SEAMLESS_Z("Z")
//usage:    IF_FEATURE_SEAMLESS_GZ("z")
//usage:    IF_FEATURE_SEAMLESS_XZ("J")
//usage:    IF_FEATURE_SEAMLESS_BZ2("j")
//usage:    IF_FEATURE_SEAMLESS_LZMA("a")
//usage:    IF_FEATURE_TAR_CREATE("h")
//usage:    IF_FEATURE_TAR_NOPRESERVE_TIME("m")
//usage:    "vO] "
//usage:    IF_FEATURE_TAR_FROM("[-X FILE] [-T FILE] ")
//usage:    "[-f TARFILE] [-C DIR] [FILE]..."
//usage:#define tar_full_usage "\n\n"
//usage:    IF_FEATURE_TAR_CREATE("Create, extract, ")
//usage:    IF_NOT_FEATURE_TAR_CREATE("Extract ")
//usage:    "or list files from a tar file\n"
//usage:     "\nOperation:"
//usage:    IF_FEATURE_TAR_CREATE(
//usage:     "\n    c   Create"
//usage:    )
//usage:     "\n    x   Extract"
//usage:     "\n    t   List"
//usage:     "\n    f   Name of TARFILE ('-' for stdin/out)"
//usage:     "\n    C   Change to DIR before operation"
//usage:     "\n    v   Verbose"
//usage:    IF_FEATURE_SEAMLESS_Z(
//usage:     "\n    Z   (De)compress using compress"
//usage:    )
//usage:    IF_FEATURE_SEAMLESS_GZ(
//usage:     "\n    z   (De)compress using gzip"
//usage:    )
//usage:    IF_FEATURE_SEAMLESS_XZ(
//usage:     "\n    J   (De)compress using xz"
//usage:    )
//usage:    IF_FEATURE_SEAMLESS_BZ2(
//usage:     "\n    j   (De)compress using bzip2"
//usage:    )
//usage:    IF_FEATURE_SEAMLESS_LZMA(
//usage:     "\n    a   (De)compress using lzma"
//usage:    )
//usage:     "\n    O   Extract to stdout"
//usage:    IF_FEATURE_TAR_CREATE(
//usage:     "\n    h   Follow symlinks"
//usage:    )
//usage:    IF_FEATURE_TAR_NOPRESERVE_TIME(
//usage:     "\n    m   Don't restore mtime"
//usage:    )
//usage:    IF_FEATURE_TAR_FROM(
//usage:    IF_FEATURE_TAR_LONG_OPTIONS(
//usage:     "\n    exclude File to exclude"
//usage:    )
//usage:     "\n    X   File with names to exclude"
//usage:     "\n    T   File with names to include"
//usage:    )
//usage:
//usage:#define tar_example_usage
//usage:       "$ zcat /tmp/tarball.tar.gz | tar -xf -\n"
//usage:       "$ tar -cf /tmp/tarball.tar /usr/local\n"

// Supported but aren't in --help:
//  o   no-same-owner
//  p   same-permissions
//  k   keep-old
//  no-recursion
//  numeric-owner
//  no-same-permissions
//  overwrite
//IF_FEATURE_TAR_TO_COMMAND(
//  to-command
//)

enum {
    OPTBIT_KEEP_OLD = 8,
    IF_FEATURE_TAR_CREATE(   OPTBIT_CREATE      ,)
    IF_FEATURE_TAR_CREATE(   OPTBIT_DEREFERENCE ,)
    IF_FEATURE_SEAMLESS_BZ2( OPTBIT_BZIP2       ,)
    IF_FEATURE_SEAMLESS_LZMA(OPTBIT_LZMA        ,)
    IF_FEATURE_TAR_FROM(     OPTBIT_INCLUDE_FROM,)
    IF_FEATURE_TAR_FROM(     OPTBIT_EXCLUDE_FROM,)
    IF_FEATURE_SEAMLESS_GZ(  OPTBIT_GZIP        ,)
    IF_FEATURE_SEAMLESS_XZ(  OPTBIT_XZ          ,) // 16th bit
    IF_FEATURE_SEAMLESS_Z(   OPTBIT_COMPRESS    ,)
    IF_FEATURE_TAR_NOPRESERVE_TIME(OPTBIT_NOPRESERVE_TIME,)
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
    OPTBIT_STRIP_COMPONENTS,
    OPTBIT_NORECURSION,
    IF_FEATURE_TAR_TO_COMMAND(OPTBIT_2COMMAND   ,)
    OPTBIT_NUMERIC_OWNER,
    OPTBIT_NOPRESERVE_PERM,
    OPTBIT_OVERWRITE,
#endif
    OPT_TEST         = 1 << 0, // t
    OPT_EXTRACT      = 1 << 1, // x
    OPT_BASEDIR      = 1 << 2, // C
    OPT_TARNAME      = 1 << 3, // f
    OPT_2STDOUT      = 1 << 4, // O
    OPT_NOPRESERVE_OWNER = 1 << 5, // o == no-same-owner
    OPT_P            = 1 << 6, // p
    OPT_VERBOSE      = 1 << 7, // v
    OPT_KEEP_OLD     = 1 << 8, // k
    OPT_CREATE       = IF_FEATURE_TAR_CREATE(   (1 << OPTBIT_CREATE      )) + 0, // c
    OPT_DEREFERENCE  = IF_FEATURE_TAR_CREATE(   (1 << OPTBIT_DEREFERENCE )) + 0, // h
    OPT_BZIP2        = IF_FEATURE_SEAMLESS_BZ2( (1 << OPTBIT_BZIP2       )) + 0, // j
    OPT_LZMA         = IF_FEATURE_SEAMLESS_LZMA((1 << OPTBIT_LZMA        )) + 0, // a
    OPT_INCLUDE_FROM = IF_FEATURE_TAR_FROM(     (1 << OPTBIT_INCLUDE_FROM)) + 0, // T
    OPT_EXCLUDE_FROM = IF_FEATURE_TAR_FROM(     (1 << OPTBIT_EXCLUDE_FROM)) + 0, // X
    OPT_GZIP         = IF_FEATURE_SEAMLESS_GZ(  (1 << OPTBIT_GZIP        )) + 0, // z
    OPT_XZ           = IF_FEATURE_SEAMLESS_XZ(  (1 << OPTBIT_XZ          )) + 0, // J
    OPT_COMPRESS     = IF_FEATURE_SEAMLESS_Z(   (1 << OPTBIT_COMPRESS    )) + 0, // Z
    OPT_NOPRESERVE_TIME  = IF_FEATURE_TAR_NOPRESERVE_TIME((1 << OPTBIT_NOPRESERVE_TIME)) + 0, // m
    OPT_STRIP_COMPONENTS = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_STRIP_COMPONENTS)) + 0, // strip-components
    OPT_NORECURSION      = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_NORECURSION    )) + 0, // no-recursion
    OPT_2COMMAND         = IF_FEATURE_TAR_TO_COMMAND(  (1 << OPTBIT_2COMMAND       )) + 0, // to-command
    OPT_NUMERIC_OWNER    = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_NUMERIC_OWNER  )) + 0, // numeric-owner
    OPT_NOPRESERVE_PERM  = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_NOPRESERVE_PERM)) + 0, // no-same-permissions
    OPT_OVERWRITE        = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_OVERWRITE      )) + 0, // overwrite

    OPT_ANY_COMPRESS = (OPT_BZIP2 | OPT_LZMA | OPT_GZIP | OPT_XZ | OPT_COMPRESS),
};
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
static const char tar_longopts[] ALIGN1 =
    "list\0"                No_argument       "t"
    "extract\0"             No_argument       "x"
    "directory\0"           Required_argument "C"
    "file\0"                Required_argument "f"
    "to-stdout\0"           No_argument       "O"
    /* do not restore owner */
    /* Note: GNU tar handles 'o' as no-same-owner only on extract,
     * on create, 'o' is --old-archive. We do not support --old-archive. */
    "no-same-owner\0"       No_argument       "o"
    "same-permissions\0"    No_argument       "p"
    "verbose\0"             No_argument       "v"
    "keep-old\0"            No_argument       "k"
# if ENABLE_FEATURE_TAR_CREATE
    "create\0"              No_argument       "c"
    "dereference\0"         No_argument       "h"
# endif
# if ENABLE_FEATURE_SEAMLESS_BZ2
    "bzip2\0"               No_argument       "j"
# endif
# if ENABLE_FEATURE_SEAMLESS_LZMA
    "lzma\0"                No_argument       "a"
# endif
# if ENABLE_FEATURE_TAR_FROM
    "files-from\0"          Required_argument "T"
    "exclude-from\0"        Required_argument "X"
# endif
# if ENABLE_FEATURE_SEAMLESS_GZ
    "gzip\0"                No_argument       "z"
# endif
# if ENABLE_FEATURE_SEAMLESS_XZ
    "xz\0"                  No_argument       "J"
# endif
# if ENABLE_FEATURE_SEAMLESS_Z
    "compress\0"            No_argument       "Z"
# endif
# if ENABLE_FEATURE_TAR_NOPRESERVE_TIME
    "touch\0"               No_argument       "m"
# endif
    "strip-components\0"    Required_argument "\xf9"
    "no-recursion\0"    No_argument       "\xfa"
# if ENABLE_FEATURE_TAR_TO_COMMAND
    "to-command\0"      Required_argument "\xfb"
# endif
    /* use numeric uid/gid from tar header, not textual */
    "numeric-owner\0"       No_argument       "\xfc"
    /* do not restore mode */
    "no-same-permissions\0" No_argument       "\xfd"
    /* on unpack, open with O_TRUNC and !O_EXCL */
    "overwrite\0"           No_argument       "\xfe"
    /* --exclude takes next bit position in option mask, */
    /* therefore we have to put it _after_ --no-same-permissions */
# if ENABLE_FEATURE_TAR_FROM
    "exclude\0"             Required_argument "\xff"
# endif
    ;
#endif

int tar_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tar_main(int argc UNUSED_PARAM, char **argv)
{
    archive_handle_t *tar_handle;
    char *base_dir = NULL;
    const char *tar_filename = "-";
    unsigned opt;
    int verboseFlag = 0;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
    llist_t *excludes = NULL;
#endif
    INIT_G();

    /* Initialise default values */
    tar_handle = init_handle();
    tar_handle->ah_flags = ARCHIVE_CREATE_LEADING_DIRS
                         | ARCHIVE_RESTORE_DATE
                         | ARCHIVE_UNLINK_OLD;

    /* Apparently only root's tar preserves perms (see bug 3844) */
    if (getuid() != 0)
        tar_handle->ah_flags |= ARCHIVE_DONT_RESTORE_PERM;

    /* Prepend '-' to the first argument if required */
    opt_complementary = "--:" // first arg is options
        "tt:vv:" // count -t,-v
        IF_FEATURE_TAR_FROM("X::T::") // cumulative lists
#if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
        "\xff::" // --exclude=PATTERN is a list
#endif
        IF_FEATURE_TAR_CREATE("c:") "t:x:" // at least one of these is reqd
        IF_FEATURE_TAR_CREATE("c--tx:t--cx:x--ct") // mutually exclusive
        IF_NOT_FEATURE_TAR_CREATE("t--x:x--t") // mutually exclusive
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
        ":\xf9+" // --strip-components=NUM
#endif
    ;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
    applet_long_options = tar_longopts;
#endif
#if ENABLE_DESKTOP
    /* Lie to buildroot when it starts asking stupid questions. */
    if (argv[1] && strcmp(argv[1], "--version") == 0) {
        // Output of 'tar --version' examples:
        // tar (GNU tar) 1.15.1
        // tar (GNU tar) 1.25
        // bsdtar 2.8.3 - libarchive 2.8.3
        puts("tar (busybox) " BB_VER);
        return 0;
    }
    if (argv[1] && argv[1][0] != '-') {
        /* Compat:
         * 1st argument without dash handles options with parameters
         * differently from dashed one: it takes *next argv[i]*
         * as paramenter even if there are more chars in 1st argument:
         *  "tar fx TARFILE" - "x" is not taken as f's param
         *  but is interpreted as -x option
         *  "tar -xf TARFILE" - dashed equivalent of the above
         *  "tar -fx ..." - "x" is taken as f's param
         * getopt32 wouldn't handle 1st command correctly.
         * Unfortunately, people do use such commands.
         * We massage argv[1] to work around it by moving 'f'
         * to the end of the string.
         * More contrived "tar fCx TARFILE DIR" still fails,
         * but such commands are much less likely to be used.
         */
        char *f = strchr(argv[1], 'f');
        if (f) {
            while (f[1] != '\0') {
                *f = f[1];
                f++;
            }
            *f = 'f';
        }
    }
#endif
    opt = getopt32(argv,
        "txC:f:Oopvk"
        IF_FEATURE_TAR_CREATE(   "ch"  )
        IF_FEATURE_SEAMLESS_BZ2( "j"   )
        IF_FEATURE_SEAMLESS_LZMA("a"   )
        IF_FEATURE_TAR_FROM(     "T:X:")
        IF_FEATURE_SEAMLESS_GZ(  "z"   )
        IF_FEATURE_SEAMLESS_XZ(  "J"   )
        IF_FEATURE_SEAMLESS_Z(   "Z"   )
        IF_FEATURE_TAR_NOPRESERVE_TIME("m")
        IF_FEATURE_TAR_LONG_OPTIONS("\xf9:") // --strip-components
        , &base_dir // -C dir
        , &tar_filename // -f filename
        IF_FEATURE_TAR_FROM(, &(tar_handle->accept)) // T
        IF_FEATURE_TAR_FROM(, &(tar_handle->reject)) // X
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
        , &tar_handle->tar__strip_components // --strip-components
#endif
        IF_FEATURE_TAR_TO_COMMAND(, &(tar_handle->tar__to_command)) // --to-command
#if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
        , &excludes // --exclude
#endif
        , &verboseFlag // combined count for -t and -v
        , &verboseFlag // combined count for -t and -v
        );
#if DBG_OPTION_PARSING
    bb_error_msg("opt: 0x%08x", opt);
# define showopt(o) bb_error_msg("opt & %s(%x): %x", #o, o, opt & o);
    showopt(OPT_TEST            );
    showopt(OPT_EXTRACT         );
    showopt(OPT_BASEDIR         );
    showopt(OPT_TARNAME         );
    showopt(OPT_2STDOUT         );
    showopt(OPT_NOPRESERVE_OWNER);
    showopt(OPT_P               );
    showopt(OPT_VERBOSE         );
    showopt(OPT_KEEP_OLD        );
    showopt(OPT_CREATE          );
    showopt(OPT_DEREFERENCE     );
    showopt(OPT_BZIP2           );
    showopt(OPT_LZMA            );
    showopt(OPT_INCLUDE_FROM    );
    showopt(OPT_EXCLUDE_FROM    );
    showopt(OPT_GZIP            );
    showopt(OPT_XZ              );
    showopt(OPT_COMPRESS        );
    showopt(OPT_NOPRESERVE_TIME );
    showopt(OPT_STRIP_COMPONENTS);
    showopt(OPT_NORECURSION     );
    showopt(OPT_2COMMAND        );
    showopt(OPT_NUMERIC_OWNER   );
    showopt(OPT_NOPRESERVE_PERM );
    showopt(OPT_OVERWRITE       );
    showopt(OPT_ANY_COMPRESS    );
    bb_error_msg("base_dir:'%s'", base_dir);
    bb_error_msg("tar_filename:'%s'", tar_filename);
    bb_error_msg("verboseFlag:%d", verboseFlag);
    bb_error_msg("tar_handle->tar__to_command:'%s'", tar_handle->tar__to_command);
    bb_error_msg("tar_handle->tar__strip_components:%u", tar_handle->tar__strip_components);
    return 0;
# undef showopt
#endif
    argv += optind;

    if (verboseFlag)
        tar_handle->action_header = header_verbose_list;
    if (verboseFlag == 1)
        tar_handle->action_header = header_list;

    if (opt & OPT_EXTRACT)
        tar_handle->action_data = data_extract_all;

    if (opt & OPT_2STDOUT)
        tar_handle->action_data = data_extract_to_stdout;

    if (opt & OPT_2COMMAND) {
        putenv((char*)"TAR_FILETYPE=f");
        signal(SIGPIPE, SIG_IGN);
        tar_handle->action_data = data_extract_to_command;
        IF_FEATURE_TAR_TO_COMMAND(tar_handle->tar__to_command_shell = xstrdup(get_shell_name());)
    }

    if (opt & OPT_KEEP_OLD)
        tar_handle->ah_flags &= ~ARCHIVE_UNLINK_OLD;

    if (opt & OPT_NUMERIC_OWNER)
        tar_handle->ah_flags |= ARCHIVE_NUMERIC_OWNER;

    if (opt & OPT_NOPRESERVE_OWNER)
        tar_handle->ah_flags |= ARCHIVE_DONT_RESTORE_OWNER;

    if (opt & OPT_NOPRESERVE_PERM)
        tar_handle->ah_flags |= ARCHIVE_DONT_RESTORE_PERM;

    if (opt & OPT_OVERWRITE) {
        tar_handle->ah_flags &= ~ARCHIVE_UNLINK_OLD;
        tar_handle->ah_flags |= ARCHIVE_O_TRUNC;
    }

    if (opt & OPT_NOPRESERVE_TIME)
        tar_handle->ah_flags &= ~ARCHIVE_RESTORE_DATE;

#if ENABLE_FEATURE_TAR_FROM
    tar_handle->reject = append_file_list_to_list(tar_handle->reject);
# if ENABLE_FEATURE_TAR_LONG_OPTIONS
    /* Append excludes to reject */
    while (excludes) {
        llist_t *next = excludes->link;
        excludes->link = tar_handle->reject;
        tar_handle->reject = excludes;
        excludes = next;
    }
# endif
    tar_handle->accept = append_file_list_to_list(tar_handle->accept);
#endif

    /* Setup an array of filenames to work with */
    /* TODO: This is the same as in ar, make a separate function? */
    while (*argv) {
        /* kill trailing '/' unless the string is just "/" */
        char *cp = last_char_is(*argv, '/');
        if (cp > *argv)
            *cp = '\0';
        llist_add_to_end(&tar_handle->accept, *argv);
        argv++;
    }

    if (tar_handle->accept || tar_handle->reject)
        tar_handle->filter = filter_accept_reject_list;

    /* Open the tar file */
    {
        int tar_fd = STDIN_FILENO;
        int flags = O_RDONLY;

        if (opt & OPT_CREATE) {
            /* Make sure there is at least one file to tar up */
            if (tar_handle->accept == NULL)
                bb_error_msg_and_die("empty archive");

            tar_fd = STDOUT_FILENO;
            /* Mimicking GNU tar 1.15.1: */
            flags = O_WRONLY | O_CREAT | O_TRUNC;
        }

        if (LONE_DASH(tar_filename)) {
            tar_handle->src_fd = tar_fd;
            tar_handle->seek = seek_by_read;
        } else {
            if (ENABLE_FEATURE_TAR_AUTODETECT
             && flags == O_RDONLY
             && !(opt & OPT_ANY_COMPRESS)
            ) {
                tar_handle->src_fd = open_zipped(tar_filename, /*fail_if_not_compressed:*/ 0);
                if (tar_handle->src_fd < 0)
                    bb_perror_msg_and_die("can't open '%s'", tar_filename);
            } else {
                tar_handle->src_fd = xopen(tar_filename, flags);
            }
        }
    }

    if (base_dir)
        xchdir(base_dir);

    //if (SEAMLESS_COMPRESSION)
    //  /* We need to know whether child (gzip/bzip/etc) exits abnormally */
    //  signal(SIGCHLD, check_errors_in_children);

#if ENABLE_FEATURE_TAR_CREATE
    /* Create an archive */
    if (opt & OPT_CREATE) {
# if SEAMLESS_COMPRESSION
        const char *zipMode = NULL;
        if (opt & OPT_COMPRESS)
            zipMode = "compress";
        if (opt & OPT_GZIP)
            zipMode = "gzip";
        if (opt & OPT_BZIP2)
            zipMode = "bzip2";
        if (opt & OPT_LZMA)
            zipMode = "lzma";
        if (opt & OPT_XZ)
            zipMode = "xz";
# endif
        /* NB: writeTarFile() closes tar_handle->src_fd */
        return writeTarFile(tar_handle->src_fd, verboseFlag,
                (opt & OPT_DEREFERENCE ? ACTION_FOLLOWLINKS : 0)
                | (opt & OPT_NORECURSION ? 0 : ACTION_RECURSE),
                tar_handle->accept,
                tar_handle->reject, zipMode);
    }
#endif

    if (opt & OPT_ANY_COMPRESS) {
        USE_FOR_MMU(IF_DESKTOP(long long) int FAST_FUNC (*xformer)(transformer_state_t *xstate);)
        USE_FOR_NOMMU(const char *xformer_prog;)

        if (opt & OPT_COMPRESS)
            USE_FOR_MMU(xformer = unpack_Z_stream;)
            USE_FOR_NOMMU(xformer_prog = "uncompress";)
        if (opt & OPT_GZIP)
            USE_FOR_MMU(xformer = unpack_gz_stream;)
            USE_FOR_NOMMU(xformer_prog = "gunzip";)
        if (opt & OPT_BZIP2)
            USE_FOR_MMU(xformer = unpack_bz2_stream;)
            USE_FOR_NOMMU(xformer_prog = "bunzip2";)
        if (opt & OPT_LZMA)
            USE_FOR_MMU(xformer = unpack_lzma_stream;)
            USE_FOR_NOMMU(xformer_prog = "unlzma";)
        if (opt & OPT_XZ)
            USE_FOR_MMU(xformer = unpack_xz_stream;)
            USE_FOR_NOMMU(xformer_prog = "unxz";)

        fork_transformer_with_sig(tar_handle->src_fd, xformer, xformer_prog);
        /* Can't lseek over pipes */
        tar_handle->seek = seek_by_read;
        /*tar_handle->offset = 0; - already is */
    }

    /* Zero processed headers (== empty file) is not a valid tarball.
     * We (ab)use bb_got_signal as exitcode here,
     * because check_errors_in_children() uses _it_ as error indicator.
     */
    bb_got_signal = EXIT_FAILURE;

    while (get_header_tar(tar_handle) == EXIT_SUCCESS)
        bb_got_signal = EXIT_SUCCESS; /* saw at least one header, good */

    /* Check that every file that should have been extracted was */
    while (tar_handle->accept) {
        if (!find_list_entry(tar_handle->reject, tar_handle->accept->data)
         && !find_list_entry(tar_handle->passed, tar_handle->accept->data)
        ) {
            bb_error_msg_and_die("%s: not found in archive",
                tar_handle->accept->data);
        }
        tar_handle->accept = tar_handle->accept->link;
    }
    if (ENABLE_FEATURE_CLEAN_UP /* && tar_handle->src_fd != STDIN_FILENO */)
        close(tar_handle->src_fd);

    if (SEAMLESS_COMPRESSION || OPT_COMPRESS) {
        /* Set bb_got_signal to 1 if a child died with !0 exitcode */
        check_errors_in_children(0);
    }

    return bb_got_signal;
}