michael@0: // Copyright (c) 2011, Google Inc.
michael@0: // All rights reserved.
michael@0: //
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: // notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: // copyright notice, this list of conditions and the following disclaimer
michael@0: // in the documentation and/or other materials provided with the
michael@0: // distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: // contributors may be used to endorse or promote products derived from
michael@0: // this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: // safe_readlink.cc: Implement google_breakpad::SafeReadLink.
michael@0: // See safe_readlink.h for details.
michael@0: 
michael@0: #include <stddef.h>
michael@0: 
michael@0: #include "third_party/lss/linux_syscall_support.h"
michael@0: 
michael@0: namespace google_breakpad {
michael@0: 
michael@0: bool SafeReadLink(const char* path, char* buffer, size_t buffer_size) {
michael@0:   // sys_readlink() does not add a NULL byte to |buffer|. In order to return
michael@0:   // a NULL-terminated string in |buffer|, |buffer_size| should be at least
michael@0:   // one byte longer than the expected path length. Also, sys_readlink()
michael@0:   // returns the actual path length on success, which does not count the
michael@0:   // NULL byte, so |result_size| should be less than |buffer_size|.
michael@0:   ssize_t result_size = sys_readlink(path, buffer, buffer_size);
michael@0:   if (result_size >= 0 && static_cast<size_t>(result_size) < buffer_size) {
michael@0:     buffer[result_size] = '\0';
michael@0:     return true;
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: }  // namespace google_breakpad