1// Copyright (c) 2011, Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8// * Redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer.
10// * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14// * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// safe_readlink.cc: Implement google_breakpad::SafeReadLink.
31// See safe_readlink.h for details.
32
33#include <stddef.h>
34
35#include "third_party/lss/linux_syscall_support.h"
36
37namespace google_breakpad {
38
39bool SafeReadLink(const char* path, char* buffer, size_t buffer_size) {
40 // sys_readlink() does not add a NULL byte to |buffer|. In order to return
41 // a NULL-terminated string in |buffer|, |buffer_size| should be at least
42 // one byte longer than the expected path length. Also, sys_readlink()
43 // returns the actual path length on success, which does not count the
44 // NULL byte, so |result_size| should be less than |buffer_size|.
45 ssize_t result_size = sys_readlink(path, buffer, buffer_size);
46 if (result_size >= 0 && static_cast<size_t>(result_size) < buffer_size) {
47 buffer[result_size] = '\0';
48 return true;
49 }
50 return false;
51}
52
53} // namespace google_breakpad
54