safe_readlink.h

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// Copyright (c) 2011, Google Inc.
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// safe_readlink.h: Define the google_breakpad::SafeReadLink function,
// which wraps sys_readlink and gurantees the result is NULL-terminated.

#ifndef COMMON_LINUX_SAFE_READLINK_H_
#define COMMON_LINUX_SAFE_READLINK_H_

#include <stddef.h>

namespace google_breakpad {

// This function wraps sys_readlink() and performs the same functionalty,
// but guarantees |buffer| is NULL-terminated if sys_readlink() returns
// no error. It takes the same arguments as sys_readlink(), but unlike
// sys_readlink(), it returns true on success.
//
// |buffer_size| specifies the size of |buffer| in bytes. As this function
// always NULL-terminates |buffer| on success, |buffer_size| should be
// at least one byte longer than the expected path length (e.g. PATH_MAX,
// which is typically defined as the maximum length of a path name
// including the NULL byte).
//
// The implementation of this function calls sys_readlink() instead of
// readlink(), it can thus be used in the context where calling to libc
// functions is discouraged.
bool SafeReadLink(const char* path, char* buffer, size_t buffer_size);

// Same as the three-argument version of SafeReadLink() but deduces the
// size of |buffer| if it is a char array of known size.
template <size_t N>
bool SafeReadLink(const char* path, char (&buffer)[N]) {
  return SafeReadLink(path, buffer, sizeof(buffer));
}

}  // namespace google_breakpad

#endif  // COMMON_LINUX_SAFE_READLINK_H_