OSX/libsecurity_utilities/lib/FileLockTransaction.cpp

   1 /*
   2  * Copyright (c) 2015 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include "FileLockTransaction.h"
  25 #include <Security/SecBasePriv.h>
  26 #include <syslog.h>
  27
  28 FileLockTransaction::FileLockTransaction(Security::CssmClient::Db& db)
  29     : mDb(db), mSuccess(false), mFinalized(false), mDeleteOnFailure(false) {
  30     initialize();
  31 }
  32
  33 void FileLockTransaction::initialize() {
  34     mDb->takeFileLock();
  35 }
  36
  37 FileLockTransaction::~FileLockTransaction() {
  38     finalize();
  39 }
  40
  41 void FileLockTransaction::success() {
  42     mSuccess = true;
  43 }
  44
  45 void FileLockTransaction::setDeleteOnFailure() {
  46     mDeleteOnFailure = true;
  47 }
  48
  49 void FileLockTransaction::finalize() {
  50     if(mFinalized) {
  51         return;
  52     }
  53
  54     // if this transaction was a success, commit. Otherwise, roll back.
  55     if(mSuccess) {
  56         mDb->releaseFileLock(true);
  57     } else {
  58         // This is a failure.
  59
  60         // Note that we're likely (but not necessarily) unwinding the stack for an exception right now.
  61         // (If this transaction succeeded, we wouldn't be here. So, it failed, and this code likes to fail with exceptions.)
  62         // If this throws an exception, we might crash the whole process.
  63         // Swallow exceptions whole, but log them aggressively.
  64         try {
  65             if(mDeleteOnFailure) {
  66                 mDb->deleteFile();
  67             }
  68             mDb->releaseFileLock(false);
  69         } catch(CssmError cssme) {
  70             const char* errStr = cssmErrorString(cssme.error);
  71             secnotice("integrity", "caught CssmError during transaction rollback: %d %s", (int) cssme.error, errStr);
  72             syslog(LOG_ERR, "ERROR: failed to rollback keychain transaction: %d %s", (int) cssme.error, errStr);
  73         }
  74     }
  75     mFinalized = true;
  76 }