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
37 namespace google_breakpad {
38
SafeReadLink(const char * path,char * buffer,size_t buffer_size)39 bool 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