source: MondoRescue/branches/2.2.5/mindi-busybox/archival/libunarchive/get_header_ar.c@ 2899

/* vi: set sw=4 ts=4: */
/* Copyright 2001 Glenn McGrath.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

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

char get_header_ar(archive_handle_t *archive_handle)
{
    int err;
    file_header_t *typed = archive_handle->file_header;
    union {
        char raw[60];
        struct {
            char name[16];
            char date[12];
            char uid[6];
            char gid[6];
            char mode[8];
            char size[10];
            char magic[2];
        } formatted;
    } ar;
#if ENABLE_FEATURE_AR_LONG_FILENAMES
    static char *ar_long_names;
    static unsigned ar_long_name_size;
#endif

    /* dont use xread as we want to handle the error ourself */
    if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
        /* End Of File */
        return EXIT_FAILURE;
    }

    /* ar header starts on an even byte (2 byte aligned)
     * '\n' is used for padding
     */
    if (ar.raw[0] == '\n') {
        /* fix up the header, we started reading 1 byte too early */
        memmove(ar.raw, &ar.raw[1], 59);
        ar.raw[59] = xread_char(archive_handle->src_fd);
        archive_handle->offset++;
    }
    archive_handle->offset += 60;

    /* align the headers based on the header magic */
    if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
        bb_error_msg_and_die("invalid ar header");

    /* FIXME: more thorough routine would be in order here */
    /* (we have something like that in tar) */
    /* but for now we are lax. This code works because */
    /* on misformatted numbers bb_strtou returns all-ones */
    typed->mode = err = bb_strtou(ar.formatted.mode, NULL, 8);
    if (err == -1) bb_error_msg_and_die("invalid ar header");
    typed->mtime = err = bb_strtou(ar.formatted.date, NULL, 10);
    if (err == -1) bb_error_msg_and_die("invalid ar header");
    typed->uid = err = bb_strtou(ar.formatted.uid, NULL, 10);
    if (err == -1) bb_error_msg_and_die("invalid ar header");
    typed->gid = err = bb_strtou(ar.formatted.gid, NULL, 10);
    if (err == -1) bb_error_msg_and_die("invalid ar header");
    typed->size = err = bb_strtou(ar.formatted.size, NULL, 10);
    if (err == -1) bb_error_msg_and_die("invalid ar header");

    /* long filenames have '/' as the first character */
    if (ar.formatted.name[0] == '/') {
#if ENABLE_FEATURE_AR_LONG_FILENAMES
        unsigned long_offset;

        if (ar.formatted.name[1] == '/') {
            /* If the second char is a '/' then this entries data section
             * stores long filename for multiple entries, they are stored
             * in static variable long_names for use in future entries */
            ar_long_name_size = typed->size;
            ar_long_names = xmalloc(ar_long_name_size);
            xread(archive_handle->src_fd, ar_long_names, ar_long_name_size);
            archive_handle->offset += ar_long_name_size;
            /* This ar entries data section only contained filenames for other records
             * they are stored in the static ar_long_names for future reference */
            return get_header_ar(archive_handle); /* Return next header */
        }

        if (ar.formatted.name[1] == ' ') {
            /* This is the index of symbols in the file for compilers */
            data_skip(archive_handle);
            archive_handle->offset += typed->size;
            return get_header_ar(archive_handle); /* Return next header */
        }

        /* The number after the '/' indicates the offset in the ar data section
         * (saved in variable long_name) that conatains the real filename */
        long_offset = atoi(&ar.formatted.name[1]);
        if (long_offset >= ar_long_name_size) {
            bb_error_msg_and_die("can't resolve long filename");
        }
        typed->name = xstrdup(ar_long_names + long_offset);
#else
        bb_error_msg_and_die("long filenames not supported");
#endif
    } else {
        /* short filenames */
        typed->name = xstrndup(ar.formatted.name, 16);
    }

    typed->name[strcspn(typed->name, " /")] = '\0';

    if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
        archive_handle->action_header(typed);
        if (archive_handle->sub_archive) {
            while (archive_handle->action_data_subarchive(archive_handle->sub_archive) == EXIT_SUCCESS)
                /* repeat */;
        } else {
            archive_handle->action_data(archive_handle);
        }
    } else {
        data_skip(archive_handle);
    }

    archive_handle->offset += typed->size;
    /* Set the file pointer to the correct spot, we may have been reading a compressed file */
    lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET);

    return EXIT_SUCCESS;
}