u-tools/apps/busybox/archival/libunarchive/get_header_cpio.c

   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
  10 typedef 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
  20 char 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 }