process.cpp

来自「功能强大的开源加密软件。使用最新ieee-p1619标准」· C++ 代码 · 共 185 行

/*
 Copyright (c) 2008 TrueCrypt Foundation. All rights reserved.

 Governed by the TrueCrypt License 2.4 the full text of which is contained
 in the file License.txt included in TrueCrypt binary and source code
 distribution packages.
*/

#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include "Process.h"
#include "Platform/Exception.h"
#include "Platform/FileStream.h"
#include "Platform/ForEach.h"
#include "Platform/MemoryStream.h"
#include "Platform/SystemException.h"
#include "Platform/StringConverter.h"
#include "Platform/Unix/Pipe.h"
#include "Platform/Unix/Poller.h"

namespace TrueCrypt
{
	string Process::Execute (const string &processName, const list <string> &arguments, int timeOut, ProcessExecFunctor *execFunctor)
	{
		char *args[32];
		if (array_capacity (args) <= arguments.size())
			throw ParameterTooLarge (SRC_POS);

#if 0
		stringstream dbg;
		dbg << "exec " << processName;
		foreach (const string &at, arguments)
			dbg << " " << at;
		trace_msg (dbg.str());
#endif

		Pipe outPipe, errPipe, exceptionPipe;

		int forkedPid = fork();
		throw_sys_if (forkedPid == -1);

		if (forkedPid == 0)
		{
			try
			{
				try
				{
					int argIndex = 0;
					if (!execFunctor)
						args[argIndex++] = const_cast <char*> (processName.c_str());

					foreach (const string &arg, arguments)
					{
						args[argIndex++] = const_cast <char*> (arg.c_str());
					}
					args[argIndex] = nullptr;

					int f = open ("/dev/null", 0);
					throw_sys_sub_if (f == -1, "/dev/null");
					throw_sys_if (dup2 (f, STDIN_FILENO) == -1);
					throw_sys_if (dup2 (outPipe.GetWriteFD(), STDOUT_FILENO) == -1);
					throw_sys_if (dup2 (errPipe.GetWriteFD(), STDERR_FILENO) == -1);
					exceptionPipe.GetWriteFD();

					if (execFunctor)
					{
						(*execFunctor)(argIndex, args);
					}
					else
					{
						execvp (args[0], args);
						throw SystemException (SRC_POS, args[0]);
					}
				}
				catch (Exception &)
				{
					throw;
				}
				catch (exception &e)
				{
					throw ExternalException (SRC_POS, StringConverter::ToExceptionString (e));
				}
				catch (...)
				{
					throw UnknownException (SRC_POS);
				}
			}
			catch (Exception &e)
			{
				try
				{
					shared_ptr <Stream> outputStream (new FileStream (exceptionPipe.GetWriteFD()));
					e.Serialize (outputStream);
				}
				catch (...) { }
			}

			_exit (1);
		}

		throw_sys_if (fcntl (outPipe.GetReadFD(), F_SETFL, O_NONBLOCK) == -1);
		throw_sys_if (fcntl (errPipe.GetReadFD(), F_SETFL, O_NONBLOCK) == -1);
		throw_sys_if (fcntl (exceptionPipe.GetReadFD(), F_SETFL, O_NONBLOCK) == -1);

		vector <char> buffer (4096), stdOutput (4096), errOutput (4096), exOutput (4096);
		buffer.clear ();
		stdOutput.clear ();
		errOutput.clear ();
		exOutput.clear ();

		Poller poller (outPipe.GetReadFD(), errPipe.GetReadFD(), exceptionPipe.GetReadFD());
		int status, waitRes;

		int timeTaken = 0;
		do
		{
			const int pollTimeout = 200;
			try
			{
				ssize_t bytesRead = 0;
				foreach (int fd, poller.WaitForData (pollTimeout))
				{
					bytesRead = read (fd, &buffer[0], buffer.capacity());
					if (bytesRead > 0)
					{
						if (fd == outPipe.GetReadFD())
							stdOutput.insert (stdOutput.end(), buffer.begin(), buffer.begin() + bytesRead);
						else if (fd == errPipe.GetReadFD())
							errOutput.insert (errOutput.end(), buffer.begin(), buffer.begin() + bytesRead);
						else if (fd == exceptionPipe.GetReadFD())
							exOutput.insert (exOutput.end(), buffer.begin(), buffer.begin() + bytesRead);
					}
				}

				if (bytesRead == 0)
				{
					waitRes = waitpid (forkedPid, &status, 0);
					break;
				}
			}
			catch (TimeOut&)
			{
				timeTaken += pollTimeout;
				if (timeOut >= 0 && timeTaken >= timeOut)
					throw;
			}
		} while ((waitRes = waitpid (forkedPid, &status, WNOHANG)) == 0);
		throw_sys_if (waitRes == -1);

		stdOutput.push_back (0);
		errOutput.push_back (0);

		if (!exOutput.empty())
		{
			auto_ptr <Serializable> deserializedObject;
			Exception *deserializedException = nullptr;

			try
			{
				shared_ptr <Stream> stream (new MemoryStream (ConstBufferPtr ((byte *) &exOutput[0], exOutput.size())));
				deserializedObject.reset (Serializable::DeserializeNew (stream));
				deserializedException = dynamic_cast <Exception*> (deserializedObject.get());
			}
			catch (...)	{ }

			if (deserializedException)
				deserializedException->Throw();
		}

		int exitCode = (WIFEXITED (status) ? WEXITSTATUS (status) : 1);
		if (exitCode != 0)
		{
			string strErrOutput;
			strErrOutput.insert (strErrOutput.begin(), errOutput.begin(), errOutput.end());
			throw ExecutedProcessFailed (SRC_POS, processName, exitCode, strErrOutput);
		}

		string strOutput;
		strOutput.insert (strOutput.begin(), stdOutput.begin(), stdOutput.end());
		return strOutput;
	}
}