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 get_header_cpio(archive_handle_t *archive_handle)
  21 {
  22         static hardlinks_t *saved_hardlinks = NULL;
  23         static hardlinks_t *saved_hardlinks_created = NULL;
  24
  25         file_header_t *file_header = archive_handle->file_header;
  26         char cpio_header[110];
  27         char dummy[16];
  28         int namesize;
  29         int major, minor, nlink, mode, inode;
  30         unsigned size, uid, gid, mtime;
  31
  32         /* There can be padding before archive header */
  33         data_align(archive_handle, 4);
  34
  35         if (archive_xread_all_eof(archive_handle, (unsigned char*)cpio_header, 110) == 0) {
  36                 goto create_hardlinks;
  37         }
  38         archive_handle->offset += 110;
  39
  40         if (strncmp(&cpio_header[0], "07070", 5) != 0
  41          || (cpio_header[5] != '1' && cpio_header[5] != '2')
  42         ) {
  43                 bb_error_msg_and_die("unsupported cpio format, use newc or crc");
  44         }
  45
  46         sscanf(cpio_header + 6,
  47                         "%8x" "%8x" "%8x" "%8x"
  48                         "%8x" "%8x" "%8x" /*maj,min:*/ "%16c"
  49                         /*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum:*/ "%8c",
  50                         &inode, &mode, &uid, &gid,
  51                         &nlink, &mtime, &size, dummy,
  52                         &major, &minor, &namesize, dummy);
  53         file_header->mode = mode;
  54         file_header->uid = uid;
  55         file_header->gid = gid;
  56         file_header->mtime = mtime;
  57         file_header->size = size;
  58
  59         file_header->name = xzalloc(namesize + 1);
  60         /* Read in filename */
  61         xread(archive_handle->src_fd, file_header->name, namesize);
  62         archive_handle->offset += namesize;
  63
  64         /* Update offset amount and skip padding before file contents */
  65         data_align(archive_handle, 4);
  66
  67         if (strcmp(file_header->name, "TRAILER!!!") == 0) {
  68                 /* Always round up. ">> 9" divides by 512 */
  69                 printf("%"OFF_FMT"u blocks\n", (archive_handle->offset + 511) >> 9);
  70                 goto create_hardlinks;
  71         }
  72
  73         if (S_ISLNK(file_header->mode)) {
  74                 file_header->link_target = xzalloc(file_header->size + 1);
  75                 xread(archive_handle->src_fd, file_header->link_target, file_header->size);
  76                 archive_handle->offset += file_header->size;
  77                 file_header->size = 0; /* Stop possible seeks in future */
  78         } else {
  79                 file_header->link_target = NULL;
  80         }
  81
  82 // TODO: data_extract_all can't deal with hardlinks to non-files...
  83 // (should be !S_ISDIR instead of S_ISREG here)
  84
  85         if (nlink > 1 && S_ISREG(file_header->mode)) {
  86                 hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
  87                 new->inode = inode;
  88                 new->mode  = mode ;
  89                 new->mtime = mtime;
  90                 new->uid   = uid  ;
  91                 new->gid   = gid  ;
  92                 strcpy(new->name, file_header->name);
  93                 /* Put file on a linked list for later */
  94                 if (size == 0) {
  95                         new->next = saved_hardlinks;
  96                         saved_hardlinks = new;
  97                         return EXIT_SUCCESS; /* Skip this one */
  98                         /* TODO: this breaks cpio -t (it does not show hardlinks) */
  99                 }
 100                 new->next = saved_hardlinks_created;
 101                 saved_hardlinks_created = new;
 102         }
 103         file_header->device = makedev(major, minor);
 104
 105         if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 106                 archive_handle->action_data(archive_handle);
 107                 archive_handle->action_header(file_header);
 108         } else {
 109                 data_skip(archive_handle);
 110         }
 111
 112         archive_handle->offset += file_header->size;
 113
 114         free(file_header->link_target);
 115         free(file_header->name);
 116         file_header->link_target = NULL;
 117         file_header->name = NULL;
 118
 119         return EXIT_SUCCESS;
 120
 121  create_hardlinks:
 122         free(file_header->link_target);
 123         free(file_header->name);
 124
 125         while (saved_hardlinks) {
 126                 hardlinks_t *cur;
 127                 hardlinks_t *make_me = saved_hardlinks;
 128                 saved_hardlinks = make_me->next;
 129
 130                 memset(file_header, 0, sizeof(*file_header));
 131                 file_header->name = make_me->name;
 132                 file_header->mode = make_me->mode;
 133                 /*file_header->size = 0;*/
 134
 135                 /* Try to find a file we are hardlinked to */
 136                 cur = saved_hardlinks_created;
 137                 while (cur) {
 138                         /* TODO: must match maj/min too! */
 139                         if (cur->inode == make_me->inode) {
 140                                 file_header->link_target = cur->name;
 141                                  /* link_target != NULL, size = 0: "I am a hardlink" */
 142                                 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 143                                         archive_handle->action_data(archive_handle);
 144                                 free(make_me);
 145                                 goto next_link;
 146                         }
 147                 }
 148                 /* Oops... no file with such inode was created... do it now
 149                  * (happens when hardlinked files are empty (zero length)) */
 150                 file_header->mtime = make_me->mtime;
 151                 file_header->uid   = make_me->uid  ;
 152                 file_header->gid   = make_me->gid  ;
 153                 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 154                         archive_handle->action_data(archive_handle);
 155                 /* Move to the list of created hardlinked files */
 156                 make_me->next = saved_hardlinks_created;
 157                 saved_hardlinks_created = make_me;
 158  next_link: ;
 159         }
 160
 161         while (saved_hardlinks_created) {
 162                 hardlinks_t *p = saved_hardlinks_created;
 163                 saved_hardlinks_created = p->next;
 164                 free(p);
 165         }
 166
 167         return EXIT_FAILURE; /* "No more files to process" */
 168 }