idevicebackup: Do not read backup files entirely into memory during restore

1 files changed, 28 insertions, 8 deletions

diff --git a/tools/idevicebackup.c b/tools/idevicebackup.c
index 0d7ba92..e30540e 100644
--- a/tools/idevicebackup.c
+++ b/tools/idevicebackup.c
@@ -1519,13 +1519,37 @@ files_out:
                                                 /* read data from file */
                                                 free(file_info_path);
                                                 file_info_path = mobilebackup_build_path(backup_directory, hash, ".mddata");
-                                                buffer_read_from_filename(file_info_path, &buffer, &length);
+
+                                                /* determine file size */
+#ifdef WIN32
+                                                struct _stati64 fst;
+                                                if (_stati64(file_info_path, &fst) != 0)
+#else
+                                                struct stat fst;
+                                                if (stat(file_info_path, &fst) != 0)
+#endif
+                                                {
+                                                        printf("ERROR: stat() failed for '%s': %s\n", file_info_path, strerror(errno));
+                                                        free(file_info_path);
+                                                        break;
+                                                }
+                                                length = fst.st_size;
+
+                                                FILE *f = fopen(file_info_path, "rb");
+                                                if (!f) {
+                                                        printf("ERROR: could not open local file '%s': %s\n", file_info_path, strerror(errno));
+                                                        free(file_info_path);
+                                                        break;
+                                                }
                                                 free(file_info_path);
 
                                                 /* send DLSendFile messages */
                                                 file_offset = 0;
                                                 do {
-                                                        if ((length-file_offset) <= 8192)
+                                                        char buf[8192];
+                                                        size_t len = fread(buf, 1, sizeof(buf), f);
+
+                                                        if ((length-file_offset) <= sizeof(buf))
                                                                 file_status = DEVICE_LINK_FILE_STATUS_LAST_HUNK;
                                                         else
                                                                 file_status = DEVICE_LINK_FILE_STATUS_HUNK;
@@ -1540,11 +1564,7 @@ files_out:
 
                                                         plist_array_append_item(send_file_node, plist_new_string("DLSendFile"));
 
-                                                        if (file_status == DEVICE_LINK_FILE_STATUS_LAST_HUNK)
-                                                                plist_array_append_item(send_file_node, plist_new_data(buffer+file_offset, length-file_offset));
-                                                        else
-                                                                plist_array_append_item(send_file_node, plist_new_data(buffer+file_offset, 8192));
-
+                                                        plist_array_append_item(send_file_node, plist_new_data(buf, len));
                                                         plist_array_append_item(send_file_node, plist_copy(file_info));
 
                                                         err = mobilebackup_send(mobilebackup, send_file_node);
@@ -1562,7 +1582,7 @@ files_out:
                                                                 }
                                                         }
 
-                                                        file_offset += 8192;
+                                                        file_offset += len;
 
                                                         if (file_status == DEVICE_LINK_FILE_STATUS_LAST_HUNK)
                                                                 printf("DONE\n");