wimlib.net Git - wimlib/blob - src/export_image.c

   1 /*
   2  * export_image.c
   3  */
   4
   5 /*
   6  * Copyright (C) 2012-2016 Eric Biggers
   7  *
   8  * This file is free software; you can redistribute it and/or modify it under
   9  * the terms of the GNU Lesser General Public License as published by the Free
  10  * Software Foundation; either version 3 of the License, or (at your option) any
  11  * later version.
  12  *
  13  * This file is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  15  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this file; if not, see http://www.gnu.org/licenses/.
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #  include "config.h"
  24 #endif
  25
  26 #include "wimlib.h"
  27 #include "wimlib/blob_table.h"
  28 #include "wimlib/error.h"
  29 #include "wimlib/inode.h"
  30 #include "wimlib/metadata.h"
  31 #include "wimlib/xml.h"
  32
  33 static int
  34 blob_set_not_exported(struct blob_descriptor *blob, void *_ignore)
  35 {
  36         blob->out_refcnt = 0;
  37         blob->was_exported = 0;
  38         return 0;
  39 }
  40
  41 static int
  42 blob_rollback_export(struct blob_descriptor *blob, void *_blob_table)
  43 {
  44         struct blob_table *blob_table = _blob_table;
  45
  46         blob->refcnt -= blob->out_refcnt;
  47         if (blob->was_exported) {
  48                 blob_table_unlink(blob_table, blob);
  49                 free_blob_descriptor(blob);
  50         }
  51         return 0;
  52 }
  53
  54 static int
  55 inode_export_blobs(struct wim_inode *inode, struct blob_table *src_blob_table,
  56                    struct blob_table *dest_blob_table, bool gift)
  57 {
  58         unsigned i;
  59         const u8 *hash;
  60         struct blob_descriptor *src_blob, *dest_blob;
  61
  62         for (i = 0; i < inode->i_num_streams; i++) {
  63
  64                 /* Retrieve SHA-1 message digest of blob to export.  */
  65                 hash = stream_hash(&inode->i_streams[i]);
  66                 if (is_zero_hash(hash))  /* Empty stream?  */
  67                         continue;
  68
  69                 /* Search for the blob (via SHA-1 message digest) in the
  70                  * destination WIM.  */
  71                 dest_blob = lookup_blob(dest_blob_table, hash);
  72                 if (!dest_blob) {
  73                         /* Blob not yet present in destination WIM.  Search for
  74                          * it in the source WIM, then export it into the
  75                          * destination WIM.  */
  76                         src_blob = stream_blob(&inode->i_streams[i],
  77                                                src_blob_table);
  78                         if (!src_blob)
  79                                 return blob_not_found_error(inode, hash);
  80
  81                         if (gift) {
  82                                 dest_blob = src_blob;
  83                                 blob_table_unlink(src_blob_table, src_blob);
  84                         } else {
  85                                 dest_blob = clone_blob_descriptor(src_blob);
  86                                 if (!dest_blob)
  87                                         return WIMLIB_ERR_NOMEM;
  88                         }
  89                         dest_blob->refcnt = 0;
  90                         dest_blob->out_refcnt = 0;
  91                         dest_blob->was_exported = 1;
  92                         blob_table_insert(dest_blob_table, dest_blob);
  93                 }
  94
  95                 /* Blob is present in destination WIM (either pre-existing,
  96                  * already exported, or just exported above).  Increment its
  97                  * reference count appropriately.   Note: we use 'refcnt' for
  98                  * the raw reference count, but 'out_refcnt' for references
  99                  * arising just from the export operation; this is used to roll
 100                  * back a failed export if needed.  */
 101                 dest_blob->refcnt += inode->i_nlink;
 102                 dest_blob->out_refcnt += inode->i_nlink;
 103         }
 104         return 0;
 105 }
 106
 107 /* API function documented in wimlib.h  */
 108 WIMLIBAPI int
 109 wimlib_export_image(WIMStruct *src_wim,
 110                     int src_image,
 111                     WIMStruct *dest_wim,
 112                     const tchar *dest_name,
 113                     const tchar *dest_description,
 114                     int export_flags)
 115 {
 116         int ret;
 117         int start_src_image;
 118         int end_src_image;
 119         int orig_dest_image_count;
 120         int image;
 121         bool all_images = (src_image == WIMLIB_ALL_IMAGES);
 122
 123         /* Check for sane parameters.  */
 124         if (export_flags & ~(WIMLIB_EXPORT_FLAG_BOOT |
 125                              WIMLIB_EXPORT_FLAG_NO_NAMES |
 126                              WIMLIB_EXPORT_FLAG_NO_DESCRIPTIONS |
 127                              WIMLIB_EXPORT_FLAG_GIFT |
 128                              WIMLIB_EXPORT_FLAG_WIMBOOT))
 129                 return WIMLIB_ERR_INVALID_PARAM;
 130
 131         if (!src_wim || !dest_wim)
 132                 return WIMLIB_ERR_INVALID_PARAM;
 133
 134         if (!wim_has_metadata(src_wim) || !wim_has_metadata(dest_wim))
 135                 return WIMLIB_ERR_METADATA_NOT_FOUND;
 136
 137         if (all_images) {
 138                 /* Multi-image export.  */
 139                 if ((!(export_flags & WIMLIB_EXPORT_FLAG_NO_NAMES) &&
 140                         dest_name) ||
 141                     (!(export_flags & WIMLIB_EXPORT_FLAG_NO_DESCRIPTIONS) &&
 142                         dest_description))
 143                 {
 144                         ERROR("Image name and description must be "
 145                               "left NULL for multi-image export");
 146                         return WIMLIB_ERR_INVALID_PARAM;
 147                 }
 148                 start_src_image = 1;
 149                 end_src_image = src_wim->hdr.image_count;
 150         } else {
 151                 start_src_image = src_image;
 152                 end_src_image = src_image;
 153         }
 154         orig_dest_image_count = dest_wim->hdr.image_count;
 155
 156         /* We don't yet support having a single WIMStruct contain duplicate
 157          * 'image_metadata' structures, so we must forbid this from happening.
 158          * A duplication is possible if 'src_wim == dest_wim', if the same image
 159          * is exported to the same destination WIMStruct multiple times, or if
 160          * an image is exported in an A => B => A manner.  */
 161         for (src_image = start_src_image;
 162              src_image <= end_src_image; src_image++)
 163         {
 164                 const struct wim_image_metadata *src_imd =
 165                                 src_wim->image_metadata[src_image - 1];
 166                 for (int i = 0; i < dest_wim->hdr.image_count; i++)
 167                         if (dest_wim->image_metadata[i] == src_imd)
 168                                 return WIMLIB_ERR_DUPLICATE_EXPORTED_IMAGE;
 169         }
 170
 171         /* Blob checksums must be known before proceeding.  */
 172         ret = wim_checksum_unhashed_blobs(src_wim);
 173         if (ret)
 174                 return ret;
 175         ret = wim_checksum_unhashed_blobs(dest_wim);
 176         if (ret)
 177                 return ret;
 178
 179         /* Enable rollbacks  */
 180         for_blob_in_table(dest_wim->blob_table, blob_set_not_exported, NULL);
 181
 182         /* Export each requested image.  */
 183         for (src_image = start_src_image;
 184              src_image <= end_src_image;
 185              src_image++)
 186         {
 187                 const tchar *next_dest_name, *next_dest_description;
 188                 struct wim_image_metadata *src_imd;
 189                 struct wim_inode *inode;
 190
 191                 /* Determine destination image name and description.  */
 192
 193                 if (export_flags & WIMLIB_EXPORT_FLAG_NO_NAMES)
 194                         next_dest_name = NULL;
 195                 else if (dest_name)
 196                         next_dest_name = dest_name;
 197                 else
 198                         next_dest_name = wimlib_get_image_name(src_wim, src_image);
 199
 200                 if (export_flags & WIMLIB_EXPORT_FLAG_NO_DESCRIPTIONS)
 201                         next_dest_description = NULL;
 202                 else if (dest_description)
 203                         next_dest_description = dest_description;
 204                 else
 205                         next_dest_description = wimlib_get_image_description(src_wim, src_image);
 206
 207                 /* Check for name conflict.  */
 208                 if (wimlib_image_name_in_use(dest_wim, next_dest_name)) {
 209                         ERROR("There is already an image named \"%"TS"\" "
 210                               "in the destination WIM", next_dest_name);
 211                         ret = WIMLIB_ERR_IMAGE_NAME_COLLISION;
 212                         goto out_rollback;
 213                 }
 214
 215                 /* Load metadata for source image into memory.  */
 216                 ret = select_wim_image(src_wim, src_image);
 217                 if (ret)
 218                         goto out_rollback;
 219
 220                 src_imd = wim_get_current_image_metadata(src_wim);
 221
 222                 /* Iterate through inodes in the source image and export their
 223                  * blobs into the destination WIM.  */
 224                 image_for_each_inode(inode, src_imd) {
 225                         ret = inode_export_blobs(inode,
 226                                                  src_wim->blob_table,
 227                                                  dest_wim->blob_table,
 228                                                  export_flags & WIMLIB_EXPORT_FLAG_GIFT);
 229                         if (ret)
 230                                 goto out_rollback;
 231                 }
 232
 233                 /* Export XML information into the destination WIM.  */
 234                 ret = xml_export_image(src_wim->xml_info, src_image,
 235                                        dest_wim->xml_info, next_dest_name,
 236                                        next_dest_description,
 237                                        export_flags & WIMLIB_EXPORT_FLAG_WIMBOOT);
 238                 if (ret)
 239                         goto out_rollback;
 240
 241                 /* Reference the source image metadata from the destination WIM.
 242                  */
 243                 ret = append_image_metadata(dest_wim, src_imd);
 244                 if (ret)
 245                         goto out_rollback;
 246                 src_imd->refcnt++;
 247         }
 248
 249         /* Image export complete.  Finish by setting any needed special metadata
 250          * on the destination WIM.  */
 251
 252         if (src_wim->hdr.flags & WIM_HDR_FLAG_RP_FIX)
 253                 dest_wim->hdr.flags |= WIM_HDR_FLAG_RP_FIX;
 254
 255         for (src_image = start_src_image;
 256              src_image <= end_src_image;
 257              src_image++)
 258         {
 259                 int dst_image = orig_dest_image_count + 1 +
 260                                 (src_image - start_src_image);
 261
 262                 if ((export_flags & WIMLIB_EXPORT_FLAG_BOOT) &&
 263                     (!all_images || src_image == src_wim->hdr.boot_idx))
 264                         dest_wim->hdr.boot_idx = dst_image;
 265         }
 266
 267         return 0;
 268
 269 out_rollback:
 270         while ((image = xml_get_image_count(dest_wim->xml_info))
 271                > orig_dest_image_count)
 272         {
 273                 xml_delete_image(dest_wim->xml_info, image);
 274         }
 275         while (dest_wim->hdr.image_count > orig_dest_image_count)
 276         {
 277                 put_image_metadata(dest_wim->image_metadata[
 278                                         --dest_wim->hdr.image_count]);
 279         }
 280         for_blob_in_table(dest_wim->blob_table, blob_rollback_export,
 281                           dest_wim->blob_table);
 282         return ret;
 283 }