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_s {
  11         struct hardlinks_s *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         char dummy[16];
  25         int namesize;
  26         int major, minor, nlink, mode, inode;
  27         unsigned size, uid, gid, mtime;
  28
  29 #define saved_hardlinks         (*(hardlinks_t **)(&archive_handle->ah_priv[0]))
  30 #define saved_hardlinks_created (*(hardlinks_t **)(&archive_handle->ah_priv[1]))
  31 //      if (!archive_handle->ah_priv_inited) {
  32 //              archive_handle->ah_priv_inited = 1;
  33 //              saved_hardlinks = NULL;
  34 //              saved_hardlinks_created = NULL;
  35 //      }
  36
  37         /* There can be padding before archive header */
  38         data_align(archive_handle, 4);
  39
  40         if (archive_xread_all_eof(archive_handle, (unsigned char*)cpio_header, 110) == 0) {
  41                 goto create_hardlinks;
  42         }
  43         archive_handle->offset += 110;
  44
  45         if (strncmp(&cpio_header[0], "07070", 5) != 0
  46          || (cpio_header[5] != '1' && cpio_header[5] != '2')
  47         ) {
  48                 bb_error_msg_and_die("unsupported cpio format, use newc or crc");
  49         }
  50
  51         sscanf(cpio_header + 6,
  52                         "%8x" "%8x" "%8x" "%8x"
  53                         "%8x" "%8x" "%8x" /*maj,min:*/ "%16c"
  54                         /*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum:*/ "%8c",
  55                         &inode, &mode, &uid, &gid,
  56                         &nlink, &mtime, &size, dummy,
  57                         &major, &minor, &namesize, dummy);
  58         file_header->mode = mode;
  59         file_header->uid = uid;
  60         file_header->gid = gid;
  61         file_header->mtime = mtime;
  62         file_header->size = size;
  63
  64         file_header->name = xzalloc(namesize + 1);
  65         /* Read in filename */
  66         xread(archive_handle->src_fd, file_header->name, namesize);
  67         archive_handle->offset += namesize;
  68
  69         /* Update offset amount and skip padding before file contents */
  70         data_align(archive_handle, 4);
  71
  72         if (strcmp(file_header->name, "TRAILER!!!") == 0) {
  73                 /* Always round up. ">> 9" divides by 512 */
  74                 printf("%"OFF_FMT"u blocks\n", (archive_handle->offset + 511) >> 9);
  75                 goto create_hardlinks;
  76         }
  77
  78         if (S_ISLNK(file_header->mode)) {
  79                 file_header->link_target = xzalloc(file_header->size + 1);
  80                 xread(archive_handle->src_fd, file_header->link_target, file_header->size);
  81                 archive_handle->offset += file_header->size;
  82                 file_header->size = 0; /* Stop possible seeks in future */
  83         } else {
  84                 file_header->link_target = NULL;
  85         }
  86
  87 // TODO: data_extract_all can't deal with hardlinks to non-files...
  88 // (should be !S_ISDIR instead of S_ISREG here)
  89
  90         if (nlink > 1 && S_ISREG(file_header->mode)) {
  91                 hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
  92                 new->inode = inode;
  93                 new->mode  = mode ;
  94                 new->mtime = mtime;
  95                 new->uid   = uid  ;
  96                 new->gid   = gid  ;
  97                 strcpy(new->name, file_header->name);
  98                 /* Put file on a linked list for later */
  99                 if (size == 0) {
 100                         new->next = saved_hardlinks;
 101                         saved_hardlinks = new;
 102                         return EXIT_SUCCESS; /* Skip this one */
 103                         /* TODO: this breaks cpio -t (it does not show hardlinks) */
 104                 }
 105                 new->next = saved_hardlinks_created;
 106                 saved_hardlinks_created = new;
 107         }
 108         file_header->device = makedev(major, minor);
 109
 110         if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 111                 archive_handle->action_data(archive_handle);
 112                 archive_handle->action_header(file_header);
 113         } else {
 114                 data_skip(archive_handle);
 115         }
 116
 117         archive_handle->offset += file_header->size;
 118
 119         free(file_header->link_target);
 120         free(file_header->name);
 121         file_header->link_target = NULL;
 122         file_header->name = NULL;
 123
 124         return EXIT_SUCCESS;
 125
 126  create_hardlinks:
 127         free(file_header->link_target);
 128         free(file_header->name);
 129
 130         while (saved_hardlinks) {
 131                 hardlinks_t *cur;
 132                 hardlinks_t *make_me = saved_hardlinks;
 133                 saved_hardlinks = make_me->next;
 134
 135                 memset(file_header, 0, sizeof(*file_header));
 136                 file_header->name = make_me->name;
 137                 file_header->mode = make_me->mode;
 138                 /*file_header->size = 0;*/
 139
 140                 /* Try to find a file we are hardlinked to */
 141                 cur = saved_hardlinks_created;
 142                 while (cur) {
 143                         /* TODO: must match maj/min too! */
 144                         if (cur->inode == make_me->inode) {
 145                                 file_header->link_target = cur->name;
 146                                  /* link_target != NULL, size = 0: "I am a hardlink" */
 147                                 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 148                                         archive_handle->action_data(archive_handle);
 149                                 free(make_me);
 150                                 goto next_link;
 151                         }
 152                 }
 153                 /* Oops... no file with such inode was created... do it now
 154                  * (happens when hardlinked files are empty (zero length)) */
 155                 file_header->mtime = make_me->mtime;
 156                 file_header->uid   = make_me->uid  ;
 157                 file_header->gid   = make_me->gid  ;
 158                 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 159                         archive_handle->action_data(archive_handle);
 160                 /* Move to the list of created hardlinked files */
 161                 make_me->next = saved_hardlinks_created;
 162                 saved_hardlinks_created = make_me;
 163  next_link: ;
 164         }
 165
 166         while (saved_hardlinks_created) {
 167                 hardlinks_t *p = saved_hardlinks_created;
 168                 saved_hardlinks_created = p->next;
 169                 free(p);
 170         }
 171
 172         return EXIT_FAILURE; /* "No more files to process" */
 173 }