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