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         char *name;
  12         int inode;
  13         struct hardlinks_s *next;
  14 } hardlinks_t;
  15
  16 char get_header_cpio(archive_handle_t *archive_handle)
  17 {
  18         static hardlinks_t *saved_hardlinks = NULL;
  19         static unsigned short pending_hardlinks = 0;
  20         static int inode;
  21         file_header_t *file_header = archive_handle->file_header;
  22         char cpio_header[110];
  23         int namesize;
  24         char dummy[16];
  25         int major, minor, nlink;
  26
  27         if (pending_hardlinks) { /* Deal with any pending hardlinks */
  28                 hardlinks_t *tmp, *oldtmp;
  29
  30                 tmp = saved_hardlinks;
  31                 oldtmp = NULL;
  32
  33                 file_header->link_name = file_header->name;
  34                 file_header->size = 0;
  35
  36                 while (tmp) {
  37                         if (tmp->inode != inode) {
  38                                 tmp = tmp->next;
  39                                 continue;
  40                         }
  41
  42                         file_header->name = tmp->name;
  43
  44                         if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
  45                                 archive_handle->action_data(archive_handle);
  46                                 archive_handle->action_header(archive_handle->file_header);
  47                         }
  48
  49                         pending_hardlinks--;
  50
  51                         oldtmp = tmp;
  52                         tmp = tmp->next;
  53                         free(oldtmp->name);
  54                         free(oldtmp);
  55                         if (oldtmp == saved_hardlinks)
  56                                 saved_hardlinks = tmp;
  57                 }
  58
  59                 file_header->name = file_header->link_name;
  60
  61                 if (pending_hardlinks > 1) {
  62                         bb_error_msg("error resolving hardlink: archive made by GNU cpio 2.0-2.2?");
  63                 }
  64
  65                 /* No more pending hardlinks, read next file entry */
  66                 pending_hardlinks = 0;
  67         }
  68
  69         /* There can be padding before archive header */
  70         data_align(archive_handle, 4);
  71
  72         if (archive_xread_all_eof(archive_handle, (unsigned char*)cpio_header, 110) == 0) {
  73                 return EXIT_FAILURE;
  74         }
  75         archive_handle->offset += 110;
  76
  77         if (strncmp(&cpio_header[0], "07070", 5) != 0
  78          || (cpio_header[5] != '1' && cpio_header[5] != '2')
  79         ) {
  80                 bb_error_msg_and_die("unsupported cpio format, use newc or crc");
  81         }
  82
  83         {
  84                 unsigned long tmpsize;
  85                 sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
  86                     dummy, &inode, (unsigned int*)&file_header->mode,
  87                     (unsigned int*)&file_header->uid, (unsigned int*)&file_header->gid,
  88                     &nlink, &file_header->mtime, &tmpsize,
  89                     dummy, &major, &minor, &namesize, dummy);
  90                 file_header->size = tmpsize;
  91         }
  92
  93         free(file_header->name);
  94         file_header->name = xzalloc(namesize + 1);
  95         /* Read in filename */
  96         xread(archive_handle->src_fd, file_header->name, namesize);
  97         archive_handle->offset += namesize;
  98
  99         /* Update offset amount and skip padding before file contents */
 100         data_align(archive_handle, 4);
 101
 102         if (strcmp(file_header->name, "TRAILER!!!") == 0) {
 103                 /* Always round up */
 104                 printf("%d blocks\n", (int) (archive_handle->offset % 512 ?
 105                                              archive_handle->offset / 512 + 1 :
 106                                              archive_handle->offset / 512
 107                                             ));
 108                 if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
 109                         hardlinks_t *tmp = saved_hardlinks;
 110                         hardlinks_t *oldtmp = NULL;
 111                         while (tmp) {
 112                                 bb_error_msg("%s not created: cannot resolve hardlink", tmp->name);
 113                                 oldtmp = tmp;
 114                                 tmp = tmp->next;
 115                                 free(oldtmp->name);
 116                                 free(oldtmp);
 117                         }
 118                         saved_hardlinks = NULL;
 119                         pending_hardlinks = 0;
 120                 }
 121                 return EXIT_FAILURE;
 122         }
 123
 124         if (S_ISLNK(file_header->mode)) {
 125                 file_header->link_name = xzalloc(file_header->size + 1);
 126                 xread(archive_handle->src_fd, file_header->link_name, file_header->size);
 127                 archive_handle->offset += file_header->size;
 128                 file_header->size = 0; /* Stop possible seeks in future */
 129         } else {
 130                 file_header->link_name = NULL;
 131         }
 132         if (nlink > 1 && !S_ISDIR(file_header->mode)) {
 133                 if (file_header->size == 0) { /* Put file on a linked list for later */
 134                         hardlinks_t *new = xmalloc(sizeof(hardlinks_t));
 135                         new->next = saved_hardlinks;
 136                         new->inode = inode;
 137                         /* name current allocated, freed later */
 138                         new->name = file_header->name;
 139                         file_header->name = NULL;
 140                         saved_hardlinks = new;
 141                         return EXIT_SUCCESS; /* Skip this one */
 142                 }
 143                 /* Found the file with data in */
 144                 pending_hardlinks = nlink;
 145         }
 146         file_header->device = makedev(major, minor);
 147
 148         if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 149                 archive_handle->action_data(archive_handle);
 150                 archive_handle->action_header(archive_handle->file_header);
 151         } else {
 152                 data_skip(archive_handle);
 153         }
 154
 155         archive_handle->offset += file_header->size;
 156
 157         free(file_header->link_name);
 158
 159         return EXIT_SUCCESS;
 160 }