LXR busybox/archival/libunarchive/get_header

   1/* vi: set sw=4 ts=4: */
   2/* Copyright 2002 Laurence Anderson
   3 *
   4 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   5 */
   6
   7#include "libbb.h"
   8#include "unarchive.h"
   9
  10typedef struct hardlinks_t {
  11        struct hardlinks_t *next;
  12        int inode; /* TODO: must match maj/min too! */
  13        int mode ;
  14        int mtime; /* These three are useful only in corner case */
  15        int uid  ; /* of hardlinks with zero size body */
  16        int gid  ;
  17        char name[1];
  18} hardlinks_t;
  19
  20char FAST_FUNC get_header_cpio(archive_handle_t *archive_handle)
  21{
  22        file_header_t *file_header = archive_handle->file_header;
  23        char cpio_header[110];
  24        int namesize;
  25        int major, minor, nlink, mode, inode;
  26        unsigned size, uid, gid, mtime;
  27
  28#define hardlinks_to_create (*(hardlinks_t **)(&archive_handle->ah_priv[0]))
  29#define created_hardlinks   (*(hardlinks_t **)(&archive_handle->ah_priv[1]))
  30#define block_count         (archive_handle->ah_priv[2])
  31//      if (!archive_handle->ah_priv_inited) {
  32//              archive_handle->ah_priv_inited = 1;
  33//              hardlinks_to_create = NULL;
  34//              created_hardlinks = NULL;
  35//      }
  36
  37        /* There can be padding before archive header */
  38        data_align(archive_handle, 4);
  39
  40        size = full_read(archive_handle->src_fd, cpio_header, 110);
  41        if (size == 0) {
  42                goto create_hardlinks;
  43        }
  44        if (size != 110) {
  45                bb_error_msg_and_die("short read");
  46        }
  47        archive_handle->offset += 110;
  48
  49        if (strncmp(&cpio_header[0], "07070", 5) != 0
  50         || (cpio_header[5] != '1' && cpio_header[5] != '2')
  51        ) {
  52                bb_error_msg_and_die("unsupported cpio format, use newc or crc");
  53        }
  54
  55        if (sscanf(cpio_header + 6,
  56                        "%8x" "%8x" "%8x" "%8x"
  57                        "%8x" "%8x" "%8x" /*maj,min:*/ "%*16c"
  58                        /*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum: "%*8c"*/,
  59                        &inode, &mode, &uid, &gid,
  60                        &nlink, &mtime, &size,
  61                        &major, &minor, &namesize) != 10)
  62                bb_error_msg_and_die("damaged cpio file");
  63        file_header->mode = mode;
  64        file_header->uid = uid;
  65        file_header->gid = gid;
  66        file_header->mtime = mtime;
  67        file_header->size = size;
  68
  69        namesize &= 0x1fff; /* paranoia: limit names to 8k chars */
  70        file_header->name = xzalloc(namesize + 1);
  71        /* Read in filename */
  72        xread(archive_handle->src_fd, file_header->name, namesize);
  73        archive_handle->offset += namesize;
  74
  75        /* Update offset amount and skip padding before file contents */
  76        data_align(archive_handle, 4);
  77
  78        if (strcmp(file_header->name, "TRAILER!!!") == 0) {
  79                /* Always round up. ">> 9" divides by 512 */
  80                block_count = (void*)(ptrdiff_t) ((archive_handle->offset + 511) >> 9);
  81                goto create_hardlinks;
  82        }
  83
  84        file_header->link_target = NULL;
  85        if (S_ISLNK(file_header->mode)) {
  86                file_header->size &= 0x1fff; /* paranoia: limit names to 8k chars */
  87                file_header->link_target = xzalloc(file_header->size + 1);
  88                xread(archive_handle->src_fd, file_header->link_target, file_header->size);
  89                archive_handle->offset += file_header->size;
  90                file_header->size = 0; /* Stop possible seeks in future */
  91        }
  92
  93// TODO: data_extract_all can't deal with hardlinks to non-files...
  94// when fixed, change S_ISREG to !S_ISDIR here
  95
  96        if (nlink > 1 && S_ISREG(file_header->mode)) {
  97                hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
  98                new->inode = inode;
  99                new->mode  = mode ;
 100                new->mtime = mtime;
 101                new->uid   = uid  ;
 102                new->gid   = gid  ;
 103                strcpy(new->name, file_header->name);
 104                /* Put file on a linked list for later */
 105                if (size == 0) {
 106                        new->next = hardlinks_to_create;
 107                        hardlinks_to_create = new;
 108                        return EXIT_SUCCESS; /* Skip this one */
 109                        /* TODO: this breaks cpio -t (it does not show hardlinks) */
 110                }
 111                new->next = created_hardlinks;
 112                created_hardlinks = new;
 113        }
 114        file_header->device = makedev(major, minor);
 115
 116        if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 117                archive_handle->action_data(archive_handle);
 118                archive_handle->action_header(file_header);
 119        } else {
 120                data_skip(archive_handle);
 121        }
 122
 123        archive_handle->offset += file_header->size;
 124
 125        free(file_header->link_target);
 126        free(file_header->name);
 127        file_header->link_target = NULL;
 128        file_header->name = NULL;
 129
 130        return EXIT_SUCCESS;
 131
 132 create_hardlinks:
 133        free(file_header->link_target);
 134        free(file_header->name);
 135
 136        while (hardlinks_to_create) {
 137                hardlinks_t *cur;
 138                hardlinks_t *make_me = hardlinks_to_create;
 139
 140                hardlinks_to_create = make_me->next;
 141
 142                memset(file_header, 0, sizeof(*file_header));
 143                file_header->mtime = make_me->mtime;
 144                file_header->name = make_me->name;
 145                file_header->mode = make_me->mode;
 146                file_header->uid = make_me->uid;
 147                file_header->gid = make_me->gid;
 148                /*file_header->size = 0;*/
 149                /*file_header->link_target = NULL;*/
 150
 151                /* Try to find a file we are hardlinked to */
 152                cur = created_hardlinks;
 153                while (cur) {
 154                        /* TODO: must match maj/min too! */
 155                        if (cur->inode == make_me->inode) {
 156                                file_header->link_target = cur->name;
 157                                 /* link_target != NULL, size = 0: "I am a hardlink" */
 158                                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 159                                        archive_handle->action_data(archive_handle);
 160                                free(make_me);
 161                                goto next_link;
 162                        }
 163                        cur = cur->next;
 164                }
 165                /* Oops... no file with such inode was created... do it now
 166                 * (happens when hardlinked files are empty (zero length)) */
 167                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 168                        archive_handle->action_data(archive_handle);
 169                /* Move to the list of created hardlinked files */
 170                make_me->next = created_hardlinks;
 171                created_hardlinks = make_me;
 172 next_link: ;
 173        }
 174
 175        while (created_hardlinks) {
 176                hardlinks_t *p = created_hardlinks;
 177                created_hardlinks = p->next;
 178                free(p);
 179        }
 180
 181        return EXIT_FAILURE; /* "No more files to process" */
 182}
 183