Handle inconsistent uncompressed resources in same way as WIMGAPI
authorEric Biggers <ebiggers3@gmail.com>
Sun, 27 Apr 2014 05:03:51 +0000 (00:03 -0500)
committerEric Biggers <ebiggers3@gmail.com>
Sun, 27 Apr 2014 05:11:11 +0000 (00:11 -0500)
src/lookup_table.c
src/resource.c

index 2cca979..1058bf2 100644 (file)
@@ -684,9 +684,27 @@ read_wim_lookup_table(WIMStruct *wim)
                if (!(reshdr.flags & (WIM_RESHDR_FLAG_PACKED_STREAMS |
                                      WIM_RESHDR_FLAG_COMPRESSED))) {
                        if (reshdr.uncompressed_size != reshdr.size_in_wim) {
-                               ERROR("Invalid resource entry!");
-                               ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
-                               goto err;
+                               /* So ... This is an uncompressed resource, but
+                                * its uncompressed size is NOT the same as its
+                                * "compressed" size (size_in_wim).  What to do
+                                * with it?
+                                *
+                                * Based on a simple test, WIMGAPI seems to
+                                * handle this as follows:
+                                *
+                                * if (size_in_wim > uncompressed_size) {
+                                *      Ignore uncompressed_size; use
+                                *      size_in_wim instead.
+                                * } else {
+                                *      Honor uncompressed_size, but treat the
+                                *      part of the file data above size_in_wim
+                                *      as all zeros.
+                                * }
+                                *
+                                * So we will do the same.
+                                */
+                               if (reshdr.size_in_wim > reshdr.uncompressed_size)
+                                       reshdr.uncompressed_size = reshdr.size_in_wim;
                        }
                }
 
index b45db59..b5db145 100644 (file)
@@ -562,6 +562,28 @@ read_error:
        goto out_free_memory;
 }
 
+static int
+fill_zeroes(u64 size, consume_data_callback_t cb, void *cb_ctx)
+{
+       if (unlikely(size)) {
+               u8 buf[min(size, BUFFER_SIZE)];
+
+               memset(buf, 0, sizeof(buf));
+
+               do {
+                       size_t len;
+                       int ret;
+
+                       len = min(size, BUFFER_SIZE);
+                       ret = cb(buf, len, cb_ctx);
+                       if (ret)
+                               return ret;
+                       size -= len;
+               } while (size);
+       }
+       return 0;
+}
+
 /* Read raw data from a file descriptor at the specified offset, feeding the
  * data it in chunks into the specified callback function.  */
 static int
@@ -654,11 +676,37 @@ read_partial_wim_resource(const struct wim_resource_spec *rspec,
                return read_compressed_wim_resource(rspec, &range, 1,
                                                    cb, cb_ctx);
        } else {
-               return read_raw_file_data(&rspec->wim->in_fd,
-                                         rspec->offset_in_wim + offset,
-                                         size,
-                                         cb,
-                                         cb_ctx);
+               /* Reading uncompressed resource.  For completeness, handle the
+                * weird case where size_in_wim < uncompressed_size.  */
+
+               u64 read_size;
+               u64 zeroes_size;
+               int ret;
+
+               if (likely(offset + size <= rspec->size_in_wim) ||
+                   rspec->is_pipable)
+               {
+                       read_size = size;
+                       zeroes_size = 0;
+               } else {
+                       if (offset >= rspec->size_in_wim) {
+                               read_size = 0;
+                               zeroes_size = size;
+                       } else {
+                               read_size = rspec->size_in_wim - offset;
+                               zeroes_size = offset + size - rspec->size_in_wim;
+                       }
+               }
+
+               ret = read_raw_file_data(&rspec->wim->in_fd,
+                                        rspec->offset_in_wim + offset,
+                                        read_size,
+                                        cb,
+                                        cb_ctx);
+               if (ret)
+                       return ret;
+
+               return fill_zeroes(zeroes_size, cb, cb_ctx);
        }
 }