busybox/archival/libunarchive/get_header_cpio.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify
   3  *  it under the terms of the GNU General Public License as published by
   4  *  the Free Software Foundation; either version 2 of the License, or
   5  *  (at your option) any later version.
   6  *
   7  *  This program is distributed in the hope that it will be useful,
   8  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  *  GNU Library General Public License for more details.
  11  *
  12  *  You should have received a copy of the GNU General Public License
  13  *  along with this program; if not, write to the Free Software
  14  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <unistd.h>
  21 #include <sys/sysmacros.h>     /* major() and minor() */
  22 #include "unarchive.h"
  23 #include "libbb.h"
  24
  25 typedef struct hardlinks_s {
  26         file_header_t *entry;
  27         int inode;
  28         struct hardlinks_s *next;
  29 } hardlinks_t;
  30
  31 extern char get_header_cpio(archive_handle_t *archive_handle)
  32 {
  33         static hardlinks_t *saved_hardlinks = NULL;
  34         static unsigned short pending_hardlinks = 0;
  35         file_header_t *file_header = archive_handle->file_header;
  36         char cpio_header[110];
  37         int namesize;
  38         char dummy[16];
  39         int major, minor, nlink, inode;
  40
  41         if (pending_hardlinks) { /* Deal with any pending hardlinks */
  42                 hardlinks_t *tmp;
  43                 hardlinks_t *oldtmp;
  44
  45                 tmp = saved_hardlinks;
  46                 oldtmp = NULL;
  47
  48                 while (tmp) {
  49                         bb_error_msg_and_die("need to fix this\n");
  50                         if (tmp->entry->link_name) { /* Found a hardlink ready to be extracted */
  51                                 file_header = tmp->entry;
  52                                 if (oldtmp) {
  53                                         oldtmp->next = tmp->next; /* Remove item from linked list */
  54                                 } else {
  55                                         saved_hardlinks = tmp->next;
  56                                 }
  57                                 free(tmp);
  58                                 continue;
  59                         }
  60                         oldtmp = tmp;
  61                         tmp = tmp->next;
  62                 }
  63                 pending_hardlinks = 0; /* No more pending hardlinks, read next file entry */
  64         }
  65
  66         /* There can be padding before archive header */
  67         data_align(archive_handle, 4);
  68
  69         if (archive_xread_all_eof(archive_handle, cpio_header, 110) == 0) {
  70                 return(EXIT_FAILURE);
  71         }
  72         archive_handle->offset += 110;
  73
  74         if ((strncmp(&cpio_header[0], "07070", 5) != 0) || ((cpio_header[5] != '1') && (cpio_header[5] != '2'))) {
  75                 bb_error_msg_and_die("Unsupported cpio format, use newc or crc");
  76         }
  77
  78         {
  79             unsigned long tmpsize;
  80             sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
  81                     dummy, &inode, (unsigned int*)&file_header->mode,
  82                     (unsigned int*)&file_header->uid, (unsigned int*)&file_header->gid,
  83                     &nlink, &file_header->mtime, &tmpsize,
  84                     dummy, &major, &minor, &namesize, dummy);
  85             file_header->size = tmpsize;
  86         }
  87
  88         file_header->name = (char *) xmalloc(namesize + 1);
  89         archive_xread_all(archive_handle, file_header->name, namesize); /* Read in filename */
  90         file_header->name[namesize] = '\0';
  91         archive_handle->offset += namesize;
  92
  93         /* Update offset amount and skip padding before file contents */
  94         data_align(archive_handle, 4);
  95
  96         if (strcmp(file_header->name, "TRAILER!!!") == 0) {
  97                 printf("%d blocks\n", (int) (archive_handle->offset % 512 ? (archive_handle->offset / 512) + 1 : archive_handle->offset / 512)); /* Always round up */
  98                 if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
  99                         hardlinks_t *tmp = saved_hardlinks;
 100                         hardlinks_t *oldtmp = NULL;
 101                         while (tmp) {
 102                                 bb_error_msg("%s not created: cannot resolve hardlink", tmp->entry->name);
 103                                 oldtmp = tmp;
 104                                 tmp = tmp->next;
 105                                 free (oldtmp->entry->name);
 106                                 free (oldtmp->entry);
 107                                 free (oldtmp);
 108                         }
 109                         saved_hardlinks = NULL;
 110                         pending_hardlinks = 0;
 111                 }
 112                 return(EXIT_FAILURE);
 113         }
 114
 115         if (S_ISLNK(file_header->mode)) {
 116                 file_header->link_name = (char *) xmalloc(file_header->size + 1);
 117                 archive_xread_all(archive_handle, file_header->link_name, file_header->size);
 118                 file_header->link_name[file_header->size] = '\0';
 119                 archive_handle->offset += file_header->size;
 120                 file_header->size = 0; /* Stop possible seeks in future */
 121         } else {
 122                 file_header->link_name = NULL;
 123         }
 124         if (nlink > 1 && !S_ISDIR(file_header->mode)) {
 125                 if (file_header->size == 0) { /* Put file on a linked list for later */
 126                         hardlinks_t *new = xmalloc(sizeof(hardlinks_t));
 127                         new->next = saved_hardlinks;
 128                         new->inode = inode;
 129                         new->entry = file_header;
 130                         saved_hardlinks = new;
 131                         return(EXIT_SUCCESS); // Skip this one
 132                 } else { /* Found the file with data in */
 133                         hardlinks_t *tmp = saved_hardlinks;
 134                         pending_hardlinks = 1;
 135                         while (tmp) {
 136                                 if (tmp->inode == inode) {
 137                                         tmp->entry->link_name = bb_xstrdup(file_header->name);
 138                                         nlink--;
 139                                 }
 140                                 tmp = tmp->next;
 141                         }
 142                         if (nlink > 1) {
 143                                 bb_error_msg("error resolving hardlink: did you create the archive with GNU cpio 2.0-2.2?");
 144                         }
 145                 }
 146         }
 147         file_header->device = makedev(major, minor);
 148
 149         if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 150                 archive_handle->action_data(archive_handle);
 151                 archive_handle->action_header(archive_handle->file_header);
 152         } else {
 153                 data_skip(archive_handle);
 154         }
 155
 156         archive_handle->offset += file_header->size;
 157
 158         free(file_header->link_name);
 159
 160         return (EXIT_SUCCESS);
 161 }