/**
* 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
inline
pid_t
posix_start(const Executable& exe,
const Arguments& args,
const environment& env,
info_map& infoin,
info_map& infoout,
const posix_setup& setup)
{
pid_t pid = ::fork();
if (pid == -1) {
boost::throw_exception
(system_error("boost::process::detail::posix_start",
"fork(2) failed", errno));
} else if (pid == 0) {
#if defined(F_MAXFD)
int maxdescs = std::max(::fcntl(0, F_MAXFD), 128); // XXX
#else
int maxdescs = 128; // XXX
#endif
try {
boost::scoped_array< bool > closeflags(new bool[maxdescs]);
for (int i = 0; i < maxdescs; i++)
closeflags.get()[i] = true;
setup_input(infoin, closeflags.get(), maxdescs);
setup_output(infoout, closeflags.get(), maxdescs);
for (int i = 0; i < maxdescs; i++)
if (closeflags.get()[i])
::close(i);
setup();
} catch (const system_error& e) {
::write(STDERR_FILENO, e.what(), std::strlen(e.what()));
::write(STDERR_FILENO, "\n", 1);
::exit(EXIT_FAILURE);
}
std::pair< std::size_t, char** > argcv =
collection_to_posix_argv(args);
char** envp = environment_to_envp(env);
::execve(exe.c_str(), argcv.second, envp);
system_error e("boost::process::detail::posix_start",
"execve(2) failed", errno);
for (std::size_t i = 0; i < argcv.first; i++)
delete [] argcv.second[i];
delete [] argcv.second;
for (std::size_t i = 0; i < env.size(); i++)
delete [] envp[i];
delete [] envp;
::write(STDERR_FILENO, e.what(), std::strlen(e.what()));
::write(STDERR_FILENO, "\n", 1);
::exit(EXIT_FAILURE);
}
BOOST_ASSERT(pid > 0);
for (info_map::iterator iter = infoin.begin();
iter != infoin.end(); iter++) {
stream_info& si = (*iter).second;
if (si.m_type == stream_info::use_pipe)
si.m_pipe->rend().close();
}
for (info_map::iterator iter = infoout.begin();
iter != infoout.end(); iter++) {
stream_info& si = (*iter).second;
if (si.m_type == stream_info::use_pipe)
si.m_pipe->wend().close();
}
return pid;
}
