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 38 namespace 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. 54 bool 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. 58 template <size_t N> 59 bool 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
