source: MondoRescue/branches/3.3/mindi-busybox/archival/libarchive/get_header_cpio.c@ 3803

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

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

typedef struct hardlinks_t {
    struct hardlinks_t *next;
    int inode; /* TODO: must match maj/min too! */
    int mode ;
    int mtime; /* These three are useful only in corner case */
    int uid  ; /* of hardlinks with zero size body */
    int gid  ;
    char name[1];
} hardlinks_t;

char FAST_FUNC get_header_cpio(archive_handle_t *archive_handle)
{
    file_header_t *file_header = archive_handle->file_header;
    char cpio_header[110];
    int namesize;
    int major, minor, nlink, mode, inode;
    unsigned size, uid, gid, mtime;

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

    size = full_read(archive_handle->src_fd, cpio_header, 110);
    if (size == 0) {
        goto create_hardlinks;
    }
    if (size != 110) {
        bb_error_msg_and_die("short read");
    }
    archive_handle->offset += 110;

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

    if (sscanf(cpio_header + 6,
            "%8x" "%8x" "%8x" "%8x"
            "%8x" "%8x" "%8x" /*maj,min:*/ "%*16c"
            /*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum: "%*8c"*/,
            &inode, &mode, &uid, &gid,
            &nlink, &mtime, &size,
            &major, &minor, &namesize) != 10)
        bb_error_msg_and_die("damaged cpio file");
    file_header->mode = mode;
    /* "cpio -R USER:GRP" support: */
    if (archive_handle->cpio__owner.uid != (uid_t)-1L)
        uid = archive_handle->cpio__owner.uid;
    if (archive_handle->cpio__owner.gid != (gid_t)-1L)
        gid = archive_handle->cpio__owner.gid;
    file_header->uid = uid;
    file_header->gid = gid;
    file_header->mtime = mtime;
    file_header->size = size;

    namesize &= 0x1fff; /* paranoia: limit names to 8k chars */
    file_header->name = xzalloc(namesize + 1);
    /* Read in filename */
    xread(archive_handle->src_fd, file_header->name, namesize);
    if (file_header->name[0] == '/') {
        /* Testcase: echo /etc/hosts | cpio -pvd /tmp
         * Without this code, it tries to unpack /etc/hosts
         * into "/etc/hosts", not "etc/hosts".
         */
        char *p = file_header->name;
        do p++; while (*p == '/');
        overlapping_strcpy(file_header->name, p);
    }
    archive_handle->offset += namesize;

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

    if (strcmp(file_header->name, cpio_TRAILER) == 0) {
        /* Always round up. ">> 9" divides by 512 */
        archive_handle->cpio__blocks = (uoff_t)(archive_handle->offset + 511) >> 9;
        goto create_hardlinks;
    }

    file_header->link_target = NULL;
    if (S_ISLNK(file_header->mode)) {
        file_header->size &= 0x1fff; /* paranoia: limit names to 8k chars */
        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 */
    }

// TODO: data_extract_all can't deal with hardlinks to non-files...
// when fixed, change S_ISREG to !S_ISDIR here

    if (nlink > 1 && S_ISREG(file_header->mode)) {
        hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
        new->inode = inode;
        new->mode  = mode ;
        new->mtime = mtime;
        new->uid   = uid  ;
        new->gid   = gid  ;
        strcpy(new->name, file_header->name);
        /* Put file on a linked list for later */
        if (size == 0) {
            new->next = archive_handle->cpio__hardlinks_to_create;
            archive_handle->cpio__hardlinks_to_create = new;
            return EXIT_SUCCESS; /* Skip this one */
            /* TODO: this breaks cpio -t (it does not show hardlinks) */
        }
        new->next = archive_handle->cpio__created_hardlinks;
        archive_handle->cpio__created_hardlinks = new;
    }
    file_header->device = makedev(major, minor);

    if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
        archive_handle->action_data(archive_handle);
//TODO: run "echo /etc/hosts | cpio -pv /tmp" twice. On 2nd run:
//cpio: etc/hosts not created: newer or same age file exists
//etc/hosts  <-- should NOT show it
//2 blocks <-- should say "0 blocks"
        archive_handle->action_header(file_header);
    } else {
        data_skip(archive_handle);
    }

    archive_handle->offset += file_header->size;

    free(file_header->link_target);
    free(file_header->name);
    file_header->link_target = NULL;
    file_header->name = NULL;

    return EXIT_SUCCESS;

 create_hardlinks:
    free(file_header->link_target);
    free(file_header->name);

    while (archive_handle->cpio__hardlinks_to_create) {
        hardlinks_t *cur;
        hardlinks_t *make_me = archive_handle->cpio__hardlinks_to_create;

        archive_handle->cpio__hardlinks_to_create = make_me->next;

        memset(file_header, 0, sizeof(*file_header));
        file_header->mtime = make_me->mtime;
        file_header->name = make_me->name;
        file_header->mode = make_me->mode;
        file_header->uid = make_me->uid;
        file_header->gid = make_me->gid;
        /*file_header->size = 0;*/
        /*file_header->link_target = NULL;*/

        /* Try to find a file we are hardlinked to */
        cur = archive_handle->cpio__created_hardlinks;
        while (cur) {
            /* TODO: must match maj/min too! */
            if (cur->inode == make_me->inode) {
                file_header->link_target = cur->name;
                 /* link_target != NULL, size = 0: "I am a hardlink" */
                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
                    archive_handle->action_data(archive_handle);
                free(make_me);
                goto next_link;
            }
            cur = cur->next;
        }
        /* Oops... no file with such inode was created... do it now
         * (happens when hardlinked files are empty (zero length)) */
        if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
            archive_handle->action_data(archive_handle);
        /* Move to the list of created hardlinked files */
        make_me->next = archive_handle->cpio__created_hardlinks;
        archive_handle->cpio__created_hardlinks = make_me;
 next_link: ;
    }

    while (archive_handle->cpio__created_hardlinks) {
        hardlinks_t *p = archive_handle->cpio__created_hardlinks;
        archive_handle->cpio__created_hardlinks = p->next;
        free(p);
    }

    return EXIT_FAILURE; /* "No more files to process" */
}