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.h: Define the google_breakpad::SafeReadLink function,
michael@0: // which wraps sys_readlink and gurantees the result is NULL-terminated.
michael@0: 
michael@0: #ifndef COMMON_LINUX_SAFE_READLINK_H_
michael@0: #define COMMON_LINUX_SAFE_READLINK_H_
michael@0: 
michael@0: #include <stddef.h>
michael@0: 
michael@0: namespace google_breakpad {
michael@0: 
michael@0: // This function wraps sys_readlink() and performs the same functionalty,
michael@0: // but guarantees |buffer| is NULL-terminated if sys_readlink() returns
michael@0: // no error. It takes the same arguments as sys_readlink(), but unlike
michael@0: // sys_readlink(), it returns true on success.
michael@0: //
michael@0: // |buffer_size| specifies the size of |buffer| in bytes. As this function
michael@0: // always NULL-terminates |buffer| on success, |buffer_size| should be
michael@0: // at least one byte longer than the expected path length (e.g. PATH_MAX,
michael@0: // which is typically defined as the maximum length of a path name
michael@0: // including the NULL byte).
michael@0: //
michael@0: // The implementation of this function calls sys_readlink() instead of
michael@0: // readlink(), it can thus be used in the context where calling to libc
michael@0: // functions is discouraged.
michael@0: bool SafeReadLink(const char* path, char* buffer, size_t buffer_size);
michael@0: 
michael@0: // Same as the three-argument version of SafeReadLink() but deduces the
michael@0: // size of |buffer| if it is a char array of known size.
michael@0: template <size_t N>
michael@0: bool SafeReadLink(const char* path, char (&buffer)[N]) {
michael@0:   return SafeReadLink(path, buffer, sizeof(buffer));
michael@0: }
michael@0: 
michael@0: }  // namespace google_breakpad
michael@0: 
michael@0: #endif  // COMMON_LINUX_SAFE_READLINK_H_