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.h: Define the google_breakpad::SafeReadLink function, 31// which wraps sys_readlink and gurantees the result is NULL-terminated. 32 33#ifndef COMMON_LINUX_SAFE_READLINK_H_ 34#define COMMON_LINUX_SAFE_READLINK_H_ 35 36#include <stddef.h> 37 38namespace google_breakpad { 39 40// This function wraps sys_readlink() and performs the same functionalty, 41// but guarantees |buffer| is NULL-terminated if sys_readlink() returns 42// no error. It takes the same arguments as sys_readlink(), but unlike 43// sys_readlink(), it returns true on success. 44// 45// |buffer_size| specifies the size of |buffer| in bytes. As this function 46// always NULL-terminates |buffer| on success, |buffer_size| should be 47// at least one byte longer than the expected path length (e.g. PATH_MAX, 48// which is typically defined as the maximum length of a path name 49// including the NULL byte). 50// 51// The implementation of this function calls sys_readlink() instead of 52// readlink(), it can thus be used in the context where calling to libc 53// functions is discouraged. 54bool SafeReadLink(const char* path, char* buffer, size_t buffer_size); 55 56// Same as the three-argument version of SafeReadLink() but deduces the 57// size of |buffer| if it is a char array of known size. 58template <size_t N> 59bool SafeReadLink(const char* path, char (&buffer)[N]) { 60 return SafeReadLink(path, buffer, sizeof(buffer)); 61} 62 63} // namespace google_breakpad 64 65#endif // COMMON_LINUX_SAFE_READLINK_H_ 66