source: MondoRescue/branches/2.2.5/mindi-busybox/archival/libunarchive/get_header_cpio.c@ 3215

/* vi: set sw=4 ts=4: */
/* Copyright 2002 Laurence Anderson
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

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

typedef struct hardlinks_s {
    char *name;
    int inode;
    struct hardlinks_s *next;
} hardlinks_t;

char get_header_cpio(archive_handle_t *archive_handle)
{
    static hardlinks_t *saved_hardlinks = NULL;
    static unsigned pending_hardlinks = 0;
    static int inode;

    file_header_t *file_header = archive_handle->file_header;
    char cpio_header[110];
    int namesize;
    char dummy[16];
    int major, minor, nlink;

    if (pending_hardlinks) { /* Deal with any pending hardlinks */
        hardlinks_t *tmp, *oldtmp;

        tmp = saved_hardlinks;
        oldtmp = NULL;

        file_header->link_target = file_header->name;
        file_header->size = 0;

        while (tmp) {
            if (tmp->inode != inode) {
                tmp = tmp->next;
                continue;
            }

            file_header->name = tmp->name;

            if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
                archive_handle->action_data(archive_handle);
                archive_handle->action_header(archive_handle->file_header);
            }

            pending_hardlinks--;

            oldtmp = tmp;
            tmp = tmp->next;
            free(oldtmp->name);
            free(oldtmp);
            if (oldtmp == saved_hardlinks)
                saved_hardlinks = tmp;
        }

        file_header->name = file_header->link_target;

        if (pending_hardlinks > 1) {
            bb_error_msg("error resolving hardlink: archive made by GNU cpio 2.0-2.2?");
        }

        /* No more pending hardlinks, read next file entry */
        pending_hardlinks = 0;
    }

    /* There can be padding before archive header */
    data_align(archive_handle, 4);

    if (archive_xread_all_eof(archive_handle, (unsigned char*)cpio_header, 110) == 0) {
        return EXIT_FAILURE;
    }
    archive_handle->offset += 110;

    if (strncmp(&cpio_header[0], "07070", 5) != 0
     || (cpio_header[5] != '1' && cpio_header[5] != '2')
    ) {
        bb_error_msg_and_die("unsupported cpio format, use newc or crc");
    }

    {
        unsigned long tmpsize;
        sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
            dummy, &inode, (unsigned int*)&file_header->mode,
            (unsigned int*)&file_header->uid, (unsigned int*)&file_header->gid,
            &nlink, &file_header->mtime, &tmpsize,
            dummy, &major, &minor, &namesize, dummy);
        file_header->size = tmpsize;
    }

    free(file_header->name);
    file_header->name = xzalloc(namesize + 1);
    /* Read in filename */
    xread(archive_handle->src_fd, file_header->name, namesize);
    archive_handle->offset += namesize;

    /* Update offset amount and skip padding before file contents */
    data_align(archive_handle, 4);

    if (strcmp(file_header->name, "TRAILER!!!") == 0) {
        /* Always round up */
        printf("%d blocks\n", (int) (archive_handle->offset % 512 ?
                                     archive_handle->offset / 512 + 1 :
                                     archive_handle->offset / 512
                                    ));
        if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
            hardlinks_t *tmp = saved_hardlinks;
            hardlinks_t *oldtmp = NULL;
            while (tmp) {
                bb_error_msg("%s not created: cannot resolve hardlink", tmp->name);
                oldtmp = tmp;
                tmp = tmp->next;
                free(oldtmp->name);
                free(oldtmp);
            }
            saved_hardlinks = NULL;
            pending_hardlinks = 0;
        }
        return EXIT_FAILURE;
    }

    if (S_ISLNK(file_header->mode)) {
        file_header->link_target = xzalloc(file_header->size + 1);
        xread(archive_handle->src_fd, file_header->link_target, file_header->size);
        archive_handle->offset += file_header->size;
        file_header->size = 0; /* Stop possible seeks in future */
    } else {
        file_header->link_target = NULL;
    }
    if (nlink > 1 && !S_ISDIR(file_header->mode)) {
        if (file_header->size == 0) { /* Put file on a linked list for later */
            hardlinks_t *new = xmalloc(sizeof(hardlinks_t));
            new->next = saved_hardlinks;
            new->inode = inode;
            /* name current allocated, freed later */
            new->name = file_header->name;
            file_header->name = NULL;
            saved_hardlinks = new;
            return EXIT_SUCCESS; /* Skip this one */
        }
        /* Found the file with data in */
        pending_hardlinks = nlink;
    }
    file_header->device = makedev(major, minor);

    if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
        archive_handle->action_data(archive_handle);
        archive_handle->action_header(archive_handle->file_header);
    } else {
        data_skip(archive_handle);
    }

    archive_handle->offset += file_header->size;

    free(file_header->link_target);

    return EXIT_SUCCESS;
}