/**
* Converts an environment to a string used by CreateProcess().
*
* Converts the environment's contents to the format used by the
* CreateProcess() system call. The returned char* string is
* allocated in dynamic memory; the caller must free it when not
* used any more. This is enforced by the use of a shared pointer.
*
* \return A dynamically allocated char* string that represents
* the environment's content. This string is of the form
* var1=value1\\0var2=value2\\0\\0.
*/
inline boost::shared_array<char> environment_to_win32_strings(const environment &env)
{
boost::shared_array<char> envp;
if (env.empty())
{
envp.reset(new char[2]);
::ZeroMemory(envp.get(), 2);
}
else
{
std::string s;
for (environment::const_iterator it = env.begin(); it != env.end(); ++it)
{
s += it->first + "=" + it->second;
s.push_back(0);
}
envp.reset(new char[s.size() + 1]);
#if defined(__CYGWIN__) || defined(_SCL_SECURE_NO_DEPRECATE)
::memcpy(envp.get(), s.c_str(), s.size() + 1);
#else
::memcpy_s(envp.get(), s.size() + 1, s.c_str(), s.size() + 1);
#endif
}
return envp;
}
/**
* Converts an environment to a char** table as used by execve().
*
* Converts the environment's contents to the format used by the
* execve() system call. The returned char** array is allocated
* in dynamic memory; the caller must free it when not used any
* more. Each entry is also allocated in dynamic memory and is a
* NULL-terminated string of the form var=value; these must also be
* released by the caller.
*
* This operation is only available on POSIX systems.
*
* \return The first argument of the pair is an integer that indicates
* how many strings are stored in the second argument. The
* second argument is a NULL-terminated, dynamically allocated
* array of dynamically allocated strings representing the
* enviroment's content. Each array entry is a NULL-terminated
* string of the form var=value. The caller is responsible for
* freeing them.
*/
inline std::pair<std::size_t, char **>
environment_to_envp(const environment
&env) {
std::size_t nargs = env.size();
char **envp = new char *[nargs + 1];
environment::size_type i = 0;
for (environment::const_iterator it = env.begin(); it != env.end(); ++it) {
std::string s = it->first + "=" + it->second;
envp[i] = new char[s.size() + 1];
std::strncpy(envp[i], s.c_str(), s.size() + 1);
++i;
}
envp[i] = 0;
return std::pair<std::size_t, char **>(nargs, envp);
} // environment_to_envp
