source: MondoRescue/branches/3.3/mindi-busybox/archival/ar.c@ 3697

/* vi: set sw=4 ts=4: */
/*
 * Mini ar implementation for busybox
 *
 * Copyright (C) 2000 by Glenn McGrath
 *
 * Based in part on BusyBox tar, Debian dpkg-deb and GNU ar.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 * Archive creation support:
 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
 * Written by Alexander Shishkin.
 *
 * There is no single standard to adhere to so ar may not portable
 * between different systems
 * http://www.unix-systems.org/single_unix_specification_v2/xcu/ar.html
 */

//config:config AR
//config:   bool "ar"
//config:   default n  # needs to be improved to be able to replace binutils ar
//config:   help
//config:     ar is an archival utility program used to create, modify, and
//config:     extract contents from archives. In practice, it is used exclusively
//config:     for object module archives used by compilers.
//config:
//config:     On an x86 system, the ar applet adds about 1K.
//config:
//config:     Unless you have a specific application which requires ar, you should
//config:     probably say N here: most compilers come with their own ar utility.
//config:
//config:config FEATURE_AR_LONG_FILENAMES
//config:   bool "Support for long filenames (not needed for debs)"
//config:   default y
//config:   depends on AR
//config:   help
//config:     By default the ar format can only store the first 15 characters
//config:     of the filename, this option removes that limitation.
//config:     It supports the GNU ar long filename method which moves multiple long
//config:     filenames into a the data section of a new ar entry.
//config:
//config:config FEATURE_AR_CREATE
//config:   bool "Support archive creation"
//config:   default y
//config:   depends on AR
//config:   help
//config:     This enables archive creation (-c and -r) with busybox ar.

//applet:IF_AR(APPLET(ar, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_AR) += ar.o

//usage:#define ar_trivial_usage
//usage:       "[-o] [-v] [-p] [-t] [-x] ARCHIVE FILES"
//usage:#define ar_full_usage "\n\n"
//usage:       "Extract or list FILES from an ar archive\n"
//usage:     "\n    -o  Preserve original dates"
//usage:     "\n    -p  Extract to stdout"
//usage:     "\n    -t  List"
//usage:     "\n    -x  Extract"
//usage:     "\n    -v  Verbose"

#include "libbb.h"
#include "bb_archive.h"
#include "ar.h"

#if ENABLE_FEATURE_AR_CREATE
/* filter out entries with same names as specified on the command line */
static char FAST_FUNC filter_replaceable(archive_handle_t *handle)
{
    if (find_list_entry(handle->accept, handle->file_header->name))
        return EXIT_FAILURE;

    return EXIT_SUCCESS;
}

static void output_ar_header(archive_handle_t *handle)
{
    /* GNU ar 2.19.51.0.14 creates malformed archives
     * if input files are >10G. It also truncates files >4GB
     * (uses "size mod 4G"). We abort in this case:
     * We could add support for up to 10G files, but this is unlikely to be useful.
     * Note that unpacking side limits all fields to "unsigned int" data type,
     * and treats "all ones" as an error indicator. Thus max we allow here is UINT_MAX-1.
     */
    enum {
        /* for 2nd field: mtime */
        MAX11CHARS = UINT_MAX > 0xffffffff ? (unsigned)99999999999 : UINT_MAX-1,
        /* for last field: filesize */
        MAX10CHARS = UINT_MAX > 0xffffffff ? (unsigned)9999999999 : UINT_MAX-1,
    };

    struct file_header_t *fh = handle->file_header;

    if (handle->offset & 1) {
        xwrite(handle->src_fd, "\n", 1);
        handle->offset++;
    }

    /* Careful! The widths should be exact. Fields must be separated */
    if (sizeof(off_t) > 4 && fh->size > (off_t)MAX10CHARS) {
        bb_error_msg_and_die("'%s' is bigger than ar can handle", fh->name);
    }
    fdprintf(handle->src_fd, "%-16.16s%-12lu%-6u%-6u%-8o%-10"OFF_FMT"u`\n",
            fh->name,
            (sizeof(time_t) > 4 && fh->mtime > MAX11CHARS) ? (long)0 : (long)fh->mtime,
            fh->uid > 99999 ? 0 : (int)fh->uid,
            fh->gid > 99999 ? 0 : (int)fh->gid,
            (int)fh->mode & 07777777,
            fh->size
    );

    handle->offset += AR_HEADER_LEN;
}

/*
 * when replacing files in an existing archive, copy from the
 * original archive those files that are to be left intact
 */
static void FAST_FUNC copy_data(archive_handle_t *handle)
{
    archive_handle_t *out_handle = handle->ar__out;
    struct file_header_t *fh = handle->file_header;

    out_handle->file_header = fh;
    output_ar_header(out_handle);

    bb_copyfd_exact_size(handle->src_fd, out_handle->src_fd, fh->size);
    out_handle->offset += fh->size;
}

static int write_ar_header(archive_handle_t *handle)
{
    char *fn;
    char fn_h[17]; /* 15 + "/" + NUL */
    struct stat st;
    int fd;

    fn = llist_pop(&handle->accept);
    if (!fn)
        return -1;

    xstat(fn, &st);

    handle->file_header->mtime = st.st_mtime;
    handle->file_header->uid = st.st_uid;
    handle->file_header->gid = st.st_gid;
    handle->file_header->mode = st.st_mode;
    handle->file_header->size = st.st_size;
    handle->file_header->name = fn_h;
//TODO: if ENABLE_FEATURE_AR_LONG_FILENAMES...
    sprintf(fn_h, "%.15s/", bb_basename(fn));

    output_ar_header(handle);

    fd = xopen(fn, O_RDONLY);
    bb_copyfd_exact_size(fd, handle->src_fd, st.st_size);
    close(fd);
    handle->offset += st.st_size;

    return 0;
}

static int write_ar_archive(archive_handle_t *handle)
{
    struct stat st;
    archive_handle_t *out_handle;

    xfstat(handle->src_fd, &st, handle->ar__name);

    /* if archive exists, create a new handle for output.
     * we create it in place of the old one.
     */
    if (st.st_size != 0) {
        out_handle = init_handle();
        xunlink(handle->ar__name);
        out_handle->src_fd = xopen(handle->ar__name, O_WRONLY | O_CREAT | O_TRUNC);
        out_handle->accept = handle->accept;
    } else {
        out_handle = handle;
    }

    handle->ar__out = out_handle;

    xwrite(out_handle->src_fd, AR_MAGIC "\n", AR_MAGIC_LEN + 1);
    out_handle->offset += AR_MAGIC_LEN + 1;

    /* skip to the end of the archive if we have to append stuff */
    if (st.st_size != 0) {
        handle->filter = filter_replaceable;
        handle->action_data = copy_data;
        unpack_ar_archive(handle);
    }

    while (write_ar_header(out_handle) == 0)
        continue;

    /* optional, since we exit right after we return */
    if (ENABLE_FEATURE_CLEAN_UP) {
        close(handle->src_fd);
        if (out_handle->src_fd != handle->src_fd)
            close(out_handle->src_fd);
    }

    return EXIT_SUCCESS;
}
#endif /* FEATURE_AR_CREATE */

static void FAST_FUNC header_verbose_list_ar(const file_header_t *file_header)
{
    const char *mode = bb_mode_string(file_header->mode);
    char *mtime;

    mtime = ctime(&file_header->mtime);
    mtime[16] = ' ';
    memmove(&mtime[17], &mtime[20], 4);
    mtime[21] = '\0';
    printf("%s %u/%u%7"OFF_FMT"u %s %s\n", &mode[1],
            (int)file_header->uid, (int)file_header->gid,
            file_header->size,
            &mtime[4], file_header->name
    );
}

#define AR_OPT_VERBOSE          (1 << 0)
#define AR_OPT_PRESERVE_DATE    (1 << 1)
/* "ar r" implies create, but warns about it. c suppresses warning.
 * bbox accepts but ignores it: */
#define AR_OPT_CREATE           (1 << 2)

#define AR_CMD_PRINT            (1 << 3)
#define FIRST_CMD               AR_CMD_PRINT
#define AR_CMD_LIST             (1 << 4)
#define AR_CMD_EXTRACT          (1 << 5)
#define AR_CMD_INSERT           (1 << 6)

int ar_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ar_main(int argc UNUSED_PARAM, char **argv)
{
    archive_handle_t *archive_handle;
    unsigned opt, t;

    archive_handle = init_handle();

    /* --: prepend '-' to the first argument if required */
    /* -1: at least one param is reqd */
    /* one of p,t,x[,r] is required */
    opt_complementary = "--:-1:p:t:x"IF_FEATURE_AR_CREATE(":r");
    opt = getopt32(argv, "voc""ptx"IF_FEATURE_AR_CREATE("r"));
    argv += optind;

    t = opt / FIRST_CMD;
    if (t & (t-1)) /* more than one of p,t,x[,r] are specified */
        bb_show_usage();

    if (opt & AR_CMD_PRINT) {
        archive_handle->action_data = data_extract_to_stdout;
    }
    if (opt & AR_CMD_LIST) {
        archive_handle->action_header = header_list;
    }
    if (opt & AR_CMD_EXTRACT) {
        archive_handle->action_data = data_extract_all;
    }
    if (opt & AR_OPT_PRESERVE_DATE) {
        archive_handle->ah_flags |= ARCHIVE_RESTORE_DATE;
    }
    if (opt & AR_OPT_VERBOSE) {
        archive_handle->action_header = header_verbose_list_ar;
    }
#if ENABLE_FEATURE_AR_CREATE
    archive_handle->ar__name = *argv;
#endif
    archive_handle->src_fd = xopen(*argv++,
            (opt & AR_CMD_INSERT)
                ? O_RDWR | O_CREAT
                : O_RDONLY
    );

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

#if ENABLE_FEATURE_AR_CREATE
    if (opt & AR_CMD_INSERT)
        return write_ar_archive(archive_handle);
#endif

    unpack_ar_archive(archive_handle);

    return EXIT_SUCCESS;
}