/* 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 the 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 tarball for details.
 */

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


//#define DBG(fmt, ...) bb_error_msg("%s: " fmt, __func__, ## __VA_ARGS__)
#define DBG(...) ((void)0)


#define block_buf bb_common_bufsiz1


#if !ENABLE_FEATURE_SEAMLESS_GZ && !ENABLE_FEATURE_SEAMLESS_BZ2
/* Do not pass gzip flag to writeTarFile() */
#define writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude, gzip) \
        writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude)
#endif


#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 */
        PUT_OCTAL(header.mtime, statbuf->st_mtime);

        /* 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)) {
                if (sizeof(statbuf->st_size) > 4
                 && statbuf->st_size > (off_t)0777777777777LL
                ) {
                        bb_error_msg_and_die("can't store file '%s' "
                                "of size %"OFF_FMT"u, aborting",
                                fileName, statbuf->st_size);
                }
                header.typeflag = REGTYPE;
                PUT_OCTAL(header.size, statbuf->st_size);
        } 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 '/' (must be before memorizing hardlink's name) */
        header_name = fileName;
        while (header_name[0] == '/') {
                static smallint warned;

                if (!warned) {
                        bb_error_msg("removing leading '/' from member names");
                        warned = 1;
                }
                header_name++;
        }

        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 ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
# if !(ENABLE_FEATURE_SEAMLESS_GZ && ENABLE_FEATURE_SEAMLESS_BZ2)
#  define vfork_compressor(tar_fd, gzip) vfork_compressor(tar_fd)
# endif
/* Don't inline: vfork scares gcc and pessimizes code */
static void NOINLINE vfork_compressor(int tar_fd, int gzip)
{
        pid_t gzipPid;
# if ENABLE_FEATURE_SEAMLESS_GZ && ENABLE_FEATURE_SEAMLESS_BZ2
        const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
# elif ENABLE_FEATURE_SEAMLESS_GZ
        const char *zip_exec = "gzip";
# else /* only ENABLE_FEATURE_SEAMLESS_BZ2 */
        const char *zip_exec = "bzip2";
# endif
        // 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 */

# if defined(__GNUC__) && __GNUC__
        /* Avoid vfork clobbering */
        (void) &zip_exec;
# endif

        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(zip_exec, zip_exec, "-f", NULL);
                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'", zip_exec);
        }
}
#endif /* ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2 */


/* gcc 4.2.1 inlines it, making code bigger */
static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
        int dereferenceFlag, const llist_t *include,
        const llist_t *exclude, int 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....  */
        if (fstat(tbInfo.tarFd, &tbInfo.tarFileStatBuf) < 0)
                bb_perror_msg_and_die("can't stat tar file");

#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
        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, ACTION_RECURSE |
                                (dereferenceFlag ? ACTION_FOLLOWLINKS : 0),
                                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 ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
        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
int writeTarFile(int tar_fd, int verboseFlag,
        int dereferenceFlag, const llist_t *include,
        const llist_t *exclude, int gzip);
#endif /* FEATURE_TAR_CREATE */

#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_for_read(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(&newlist, line);
                }
                fclose(src_stream);
        }
        return newlist;
}
#else
# define append_file_list_to_list(x) 0
#endif

#if ENABLE_FEATURE_SEAMLESS_Z
static char FAST_FUNC get_header_tar_Z(archive_handle_t *archive_handle)
{
        /* Can't lseek over pipes */
        archive_handle->seek = seek_by_read;

        /* do the decompression, and cleanup */
        if (xread_char(archive_handle->src_fd) != 0x1f
         || xread_char(archive_handle->src_fd) != 0x9d
        ) {
                bb_error_msg_and_die("invalid magic");
        }

        open_transformer(archive_handle->src_fd, unpack_Z_stream, "uncompress");
        archive_handle->offset = 0;
        while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                continue;

        /* Can only do one file at a time */
        return EXIT_FAILURE;
}
#else
# define get_header_tar_Z NULL
#endif

#ifdef CHECK_FOR_CHILD_EXITCODE
/* Looks like it isn't needed - tar detects malformed (truncated)
 * archive if e.g. bunzip2 fails */
static int child_error;

static void handle_SIGCHLD(int status)
{
        /* Actually, 'status' is a signo. We reuse it for other needs */

        /* Wait for any child without blocking */
        if (wait_any_nohang(&status) < 0)
                /* wait failed?! I'm confused... */
                return;

        if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
                /* child exited with 0 */
                return;
        /* Cannot happen?
        if (!WIFSIGNALED(status) && !WIFEXITED(status)) return; */
        child_error = 1;
}
#endif

//usage:#define tar_trivial_usage
//usage:       "-[" IF_FEATURE_TAR_CREATE("c") "xt" IF_FEATURE_SEAMLESS_GZ("z")
//usage:        IF_FEATURE_SEAMLESS_BZ2("j") IF_FEATURE_SEAMLESS_LZMA("a")
//usage:        IF_FEATURE_SEAMLESS_Z("Z") IF_FEATURE_TAR_NOPRESERVE_TIME("m") "vO] "
//usage:        IF_FEATURE_TAR_FROM("[-X 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:     "\nOptions:"
//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_GZ(
//usage:     "\n        z       (De)compress using gzip"
//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:        IF_FEATURE_SEAMLESS_Z(
//usage:     "\n        Z       (De)compress using compress"
//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
//      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_Z(   OPTBIT_COMPRESS    ,) // 16th bit
        IF_FEATURE_TAR_NOPRESERVE_TIME(OPTBIT_NOPRESERVE_TIME,)
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
        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_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_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
};
#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_Z
        "compress\0"            No_argument       "Z"
# endif
# if ENABLE_FEATURE_TAR_NOPRESERVE_TIME
        "touch\0"               No_argument       "m"
# endif
# 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)
{
        char FAST_FUNC (*get_header_ptr)(archive_handle_t *) = get_header_tar;
        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

        /* 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
                "?:" // bail out with usage instead of error return
                "X::T::" // cumulative lists
#if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
                "\xff::" // cumulative lists for --exclude
#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
        applet_long_options = tar_longopts;
#endif
#if ENABLE_DESKTOP
        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_Z(   "Z"   )
                IF_FEATURE_TAR_NOPRESERVE_TIME("m")
                , &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_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
                );
        //bb_error_msg("opt:%08x", opt);
        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 (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_GZIP)
                get_header_ptr = get_header_tar_gz;

        if (opt & OPT_BZIP2)
                get_header_ptr = get_header_tar_bz2;

        if (opt & OPT_LZMA)
                get_header_ptr = get_header_tar_lzma;

        if (opt & OPT_COMPRESS)
                get_header_ptr = get_header_tar_Z;

        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) {
                                get_header_ptr = get_header_tar;
                                tar_handle->src_fd = open_zipped(tar_filename);
                                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);

#ifdef CHECK_FOR_CHILD_EXITCODE
        /* We need to know whether child (gzip/bzip/etc) exits abnormally */
        signal(SIGCHLD, handle_SIGCHLD);
#endif

        /* Create an archive */
        if (opt & OPT_CREATE) {
#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
                int zipMode = 0;
                if (ENABLE_FEATURE_SEAMLESS_GZ && (opt & OPT_GZIP))
                        zipMode = 1;
                if (ENABLE_FEATURE_SEAMLESS_BZ2 && (opt & OPT_BZIP2))
                        zipMode = 2;
#endif
                /* NB: writeTarFile() closes tar_handle->src_fd */
                return writeTarFile(tar_handle->src_fd, verboseFlag, opt & OPT_DEREFERENCE,
                                tar_handle->accept,
                                tar_handle->reject, zipMode);
        }

        while (get_header_ptr(tar_handle) == EXIT_SUCCESS)
                continue;

        /* 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);

        return EXIT_SUCCESS;
}