lib/Support/Unix/Program.inc - platform/external/llvm - Git at Google

 //===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the Unix specific portion of the Program class.
 //
 //===----------------------------------------------------------------------===//

 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only generic UNIX code that
 //===          is guaranteed to work on *all* UNIX variants.
 //===----------------------------------------------------------------------===//

 #include "Unix.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/FileSystem.h"
 #include <llvm/Config/config.h>
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
 #if HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
 #if HAVE_SIGNAL_H
 #include <signal.h>
 #endif
 #if HAVE_FCNTL_H
 #include <fcntl.h>
 #endif
 #ifdef HAVE_POSIX_SPAWN
 #include <spawn.h>
 #if !defined(__APPLE__)
   extern char **environ;
 #else
 #include <crt_externs.h> // _NSGetEnviron
 #endif
 #endif

 namespace llvm {
 using namespace sys;

 Program::Program() : Data_(0) {}

 Program::~Program() {}

 // This function just uses the PATH environment variable to find the program.
 Path
 Program::FindProgramByName(const std::string& progName) {

   // Check some degenerate cases
   if (progName.length() == 0) // no program
     return Path();
   Path temp;
   if (!temp.set(progName)) // invalid name
     return Path();
   // Use the given path verbatim if it contains any slashes; this matches
   // the behavior of sh(1) and friends.
   if (progName.find('/') != std::string::npos)
     return temp;

   // At this point, the file name is valid and does not contain slashes. Search
   // for it through the directories specified in the PATH environment variable.

   // Get the path. If its empty, we can't do anything to find it.
   const char *PathStr = getenv("PATH");
   if (PathStr == 0)
     return Path();

   // Now we have a colon separated list of directories to search; try them.
   size_t PathLen = strlen(PathStr);
   while (PathLen) {
     // Find the first colon...
     const char *Colon = std::find(PathStr, PathStr+PathLen, ':');

     // Check to see if this first directory contains the executable...
     Path FilePath;
     if (FilePath.set(std::string(PathStr,Colon))) {
       FilePath.appendComponent(progName);
       if (FilePath.canExecute())
         return FilePath;                    // Found the executable!
     }

     // Nope it wasn't in this directory, check the next path in the list!
     PathLen -= Colon-PathStr;
     PathStr = Colon;

     // Advance past duplicate colons
     while (*PathStr == ':') {
       PathStr++;
       PathLen--;
     }
   }
   return Path();
 }

 static bool RedirectIO(const Path *Path, int FD, std::string* ErrMsg) {
   if (Path == 0) // Noop
     return false;
   const char *File;
   if (Path->isEmpty())
     // Redirect empty paths to /dev/null
     File = "/dev/null";
   else
     File = Path->c_str();

   // Open the file
   int InFD = open(File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
   if (InFD == -1) {
     MakeErrMsg(ErrMsg, "Cannot open file '" + std::string(File) + "' for "
               + (FD == 0 ? "input" : "output"));
     return true;
   }

   // Install it as the requested FD
   if (dup2(InFD, FD) == -1) {
     MakeErrMsg(ErrMsg, "Cannot dup2");
     close(InFD);
     return true;
   }
   close(InFD);      // Close the original FD
   return false;
 }

 #ifdef HAVE_POSIX_SPAWN
 static bool RedirectIO_PS(const Path *Path, int FD, std::string *ErrMsg,
                           posix_spawn_file_actions_t *FileActions) {
   if (Path == 0) // Noop
     return false;
   const char *File;
   if (Path->isEmpty())
     // Redirect empty paths to /dev/null
     File = "/dev/null";
   else
     File = Path->c_str();

   if (int Err = posix_spawn_file_actions_addopen(FileActions, FD,
                             File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666))
     return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
   return false;
 }
 #endif

 static void TimeOutHandler(int Sig) {
 }

 static void SetMemoryLimits (unsigned size)
 {
 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
   struct rlimit r;
   __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;

   // Heap size
   getrlimit (RLIMIT_DATA, &r);
   r.rlim_cur = limit;
   setrlimit (RLIMIT_DATA, &r);
 #ifdef RLIMIT_RSS
   // Resident set size.
   getrlimit (RLIMIT_RSS, &r);
   r.rlim_cur = limit;
   setrlimit (RLIMIT_RSS, &r);
 #endif
 #ifdef RLIMIT_AS  // e.g. NetBSD doesn't have it.
   // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
   // of virtual memory for shadow memory mapping.
 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
   // Virtual memory.
   getrlimit (RLIMIT_AS, &r);
   r.rlim_cur = limit;
   setrlimit (RLIMIT_AS, &r);
 #endif
 #endif
 #endif
 }

 bool
 Program::Execute(const Path &path, const char **args, const char **envp,
                  const Path **redirects, unsigned memoryLimit,
                   std::string *ErrMsg) {
   // If this OS has posix_spawn and there is no memory limit being implied, use
   // posix_spawn.  It is more efficient than fork/exec.
 #ifdef HAVE_POSIX_SPAWN
   if (memoryLimit == 0) {
     posix_spawn_file_actions_t FileActionsStore;
     posix_spawn_file_actions_t *FileActions = 0;

     if (redirects) {
       FileActions = &FileActionsStore;
       posix_spawn_file_actions_init(FileActions);

       // Redirect stdin/stdout.
       if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) ||
           RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
         return false;
       if (redirects[1] == 0 || redirects[2] == 0 ||
           *redirects[1] != *redirects[2]) {
         // Just redirect stderr
         if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions)) return false;
       } else {
         // If stdout and stderr should go to the same place, redirect stderr
         // to the FD already open for stdout.
         if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
           return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
       }
     }

     if (!envp)
 #if !defined(__APPLE__)
       envp = const_cast<const char **>(environ);
 #else
       // environ is missing in dylibs.
       envp = const_cast<const char **>(*_NSGetEnviron());
 #endif

     // Explicitly initialized to prevent what appears to be a valgrind false
     // positive.
     pid_t PID = 0;
     int Err = posix_spawn(&PID, path.c_str(), FileActions, /*attrp*/0,
                           const_cast<char **>(args), const_cast<char **>(envp));

     if (FileActions)
       posix_spawn_file_actions_destroy(FileActions);

     if (Err)
      return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);

     Data_ = reinterpret_cast<void*>(PID);
     return true;
   }
 #endif

   // Create a child process.
   int child = fork();
   switch (child) {
     // An error occurred:  Return to the caller.
     case -1:
       MakeErrMsg(ErrMsg, "Couldn't fork");
       return false;

     // Child process: Execute the program.
     case 0: {
       // Redirect file descriptors...
       if (redirects) {
         // Redirect stdin
         if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
         // Redirect stdout
         if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
         if (redirects[1] && redirects[2] &&
             *(redirects[1]) == *(redirects[2])) {
           // If stdout and stderr should go to the same place, redirect stderr
           // to the FD already open for stdout.
           if (-1 == dup2(1,2)) {
             MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
             return false;
           }
         } else {
           // Just redirect stderr
           if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
         }
       }

       // Set memory limits
       if (memoryLimit!=0) {
         SetMemoryLimits(memoryLimit);
       }

       // Execute!
       if (envp != 0)
         execve(path.c_str(),
                const_cast<char **>(args),
                const_cast<char **>(envp));
       else
         execv(path.c_str(),
               const_cast<char **>(args));
       // If the execve() failed, we should exit. Follow Unix protocol and
       // return 127 if the executable was not found, and 126 otherwise.
       // Use _exit rather than exit so that atexit functions and static
       // object destructors cloned from the parent process aren't
       // redundantly run, and so that any data buffered in stdio buffers
       // cloned from the parent aren't redundantly written out.
       _exit(errno == ENOENT ? 127 : 126);
     }

     // Parent process: Break out of the switch to do our processing.
     default:
       break;
   }

   Data_ = reinterpret_cast<void*>(child);

   return true;
 }

 int
 Program::Wait(const sys::Path &path,
               unsigned secondsToWait,
               std::string* ErrMsg)
 {
 #ifdef HAVE_SYS_WAIT_H
   struct sigaction Act, Old;

   if (Data_ == 0) {
     MakeErrMsg(ErrMsg, "Process not started!");
     return -1;
   }

   // Install a timeout handler.  The handler itself does nothing, but the simple
   // fact of having a handler at all causes the wait below to return with EINTR,
   // unlike if we used SIG_IGN.
   if (secondsToWait) {
     memset(&Act, 0, sizeof(Act));
     Act.sa_handler = TimeOutHandler;
     sigemptyset(&Act.sa_mask);
     sigaction(SIGALRM, &Act, &Old);
     alarm(secondsToWait);
   }

   // Parent process: Wait for the child process to terminate.
   int status;
   uint64_t pid = reinterpret_cast<uint64_t>(Data_);
   pid_t child = static_cast<pid_t>(pid);
   while (waitpid(pid, &status, 0) != child)
     if (secondsToWait && errno == EINTR) {
       // Kill the child.
       kill(child, SIGKILL);

       // Turn off the alarm and restore the signal handler
       alarm(0);
       sigaction(SIGALRM, &Old, 0);

       // Wait for child to die
       if (wait(&status) != child)
         MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
       else
         MakeErrMsg(ErrMsg, "Child timed out", 0);

       return -2;   // Timeout detected
     } else if (errno != EINTR) {
       MakeErrMsg(ErrMsg, "Error waiting for child process");
       return -1;
     }

   // We exited normally without timeout, so turn off the timer.
   if (secondsToWait) {
     alarm(0);
     sigaction(SIGALRM, &Old, 0);
   }

   // Return the proper exit status. Detect error conditions
   // so we can return -1 for them and set ErrMsg informatively.
   int result = 0;
   if (WIFEXITED(status)) {
     result = WEXITSTATUS(status);
 #ifdef HAVE_POSIX_SPAWN
     // The posix_spawn child process returns 127 on any kind of error.
     // Following the POSIX convention for command-line tools (which posix_spawn
     // itself apparently does not), check to see if the failure was due to some
     // reason other than the file not existing, and return 126 in this case.
     bool Exists;
     if (result == 127 && !llvm::sys::fs::exists(path.str(), Exists) && Exists)
       result = 126;
 #endif
     if (result == 127) {
       if (ErrMsg)
         *ErrMsg = llvm::sys::StrError(ENOENT);
       return -1;
     }
     if (result == 126) {
       if (ErrMsg)
         *ErrMsg = "Program could not be executed";
       return -1;
     }
   } else if (WIFSIGNALED(status)) {
     if (ErrMsg) {
       *ErrMsg = strsignal(WTERMSIG(status));
 #ifdef WCOREDUMP
       if (WCOREDUMP(status))
         *ErrMsg += " (core dumped)";
 #endif
     }
     // Return a special value to indicate that the process received an unhandled
     // signal during execution as opposed to failing to execute.
     return -2;
   }
   return result;
 #else
   if (ErrMsg)
     *ErrMsg = "Program::Wait is not implemented on this platform yet!";
   return -1;
 #endif
 }

 error_code Program::ChangeStdinToBinary(){
   // Do nothing, as Unix doesn't differentiate between text and binary.
   return make_error_code(errc::success);
 }

 error_code Program::ChangeStdoutToBinary(){
   // Do nothing, as Unix doesn't differentiate between text and binary.
   return make_error_code(errc::success);
 }

 error_code Program::ChangeStderrToBinary(){
   // Do nothing, as Unix doesn't differentiate between text and binary.
   return make_error_code(errc::success);
 }

 }
	//===- llvm/Support/Unix/Program.cpp ------------------------------ C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the Unix specific portion of the Program class.
	//
	//===----------------------------------------------------------------------===//

	//===----------------------------------------------------------------------===//
	//=== WARNING: Implementation here must contain only generic UNIX code that
	//=== is guaranteed to work on all UNIX variants.
	//===----------------------------------------------------------------------===//

	#include "Unix.h"
	#include "llvm/Support/Compiler.h"
	#include "llvm/Support/FileSystem.h"
	#include <llvm/Config/config.h>
	#if HAVE_SYS_STAT_H
	#include <sys/stat.h>
	#endif
	#if HAVE_SYS_RESOURCE_H
	#include <sys/resource.h>
	#endif
	#if HAVE_SIGNAL_H
	#include <signal.h>
	#endif
	#if HAVE_FCNTL_H
	#include <fcntl.h>
	#endif
	#ifdef HAVE_POSIX_SPAWN
	#include <spawn.h>
	#if !defined(__APPLE__)
	extern char **environ;
	#else
	#include <crt_externs.h> // _NSGetEnviron
	#endif
	#endif

	namespace llvm {
	using namespace sys;

	Program::Program() : Data_(0) {}

	Program::~Program() {}

	// This function just uses the PATH environment variable to find the program.
	Path
	Program::FindProgramByName(const std::string& progName) {

	// Check some degenerate cases
	if (progName.length() == 0) // no program
	return Path();
	Path temp;
	if (!temp.set(progName)) // invalid name
	return Path();
	// Use the given path verbatim if it contains any slashes; this matches
	// the behavior of sh(1) and friends.
	if (progName.find('/') != std::string::npos)
	return temp;

	// At this point, the file name is valid and does not contain slashes. Search
	// for it through the directories specified in the PATH environment variable.

	// Get the path. If its empty, we can't do anything to find it.
	const char *PathStr = getenv("PATH");
	if (PathStr == 0)
	return Path();

	// Now we have a colon separated list of directories to search; try them.
	size_t PathLen = strlen(PathStr);
	while (PathLen) {
	// Find the first colon...
	const char *Colon = std::find(PathStr, PathStr+PathLen, ':');

	// Check to see if this first directory contains the executable...
	Path FilePath;
	if (FilePath.set(std::string(PathStr,Colon))) {
	FilePath.appendComponent(progName);
	if (FilePath.canExecute())
	return FilePath; // Found the executable!
	}

	// Nope it wasn't in this directory, check the next path in the list!
	PathLen -= Colon-PathStr;
	PathStr = Colon;

	// Advance past duplicate colons
	while (*PathStr == ':') {
	PathStr++;
	PathLen--;
	}
	}
	return Path();
	}

	static bool RedirectIO(const Path Path, int FD, std::string ErrMsg) {
	if (Path == 0) // Noop
	return false;
	const char *File;
	if (Path->isEmpty())
	// Redirect empty paths to /dev/null
	File = "/dev/null";
	else
	File = Path->c_str();

	// Open the file
	int InFD = open(File, FD == 0 ? O_RDONLY : O_WRONLY\|O_CREAT, 0666);
	if (InFD == -1) {
	MakeErrMsg(ErrMsg, "Cannot open file '" + std::string(File) + "' for "
	+ (FD == 0 ? "input" : "output"));
	return true;
	}

	// Install it as the requested FD
	if (dup2(InFD, FD) == -1) {
	MakeErrMsg(ErrMsg, "Cannot dup2");
	close(InFD);
	return true;
	}
	close(InFD); // Close the original FD
	return false;
	}

	#ifdef HAVE_POSIX_SPAWN
	static bool RedirectIO_PS(const Path Path, int FD, std::string ErrMsg,
	posix_spawn_file_actions_t *FileActions) {
	if (Path == 0) // Noop
	return false;
	const char *File;
	if (Path->isEmpty())
	// Redirect empty paths to /dev/null
	File = "/dev/null";
	else
	File = Path->c_str();

	if (int Err = posix_spawn_file_actions_addopen(FileActions, FD,
	File, FD == 0 ? O_RDONLY : O_WRONLY\|O_CREAT, 0666))
	return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
	return false;
	}
	#endif

	static void TimeOutHandler(int Sig) {
	}

	static void SetMemoryLimits (unsigned size)
	{
	#if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
	struct rlimit r;
	__typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;

	// Heap size
	getrlimit (RLIMIT_DATA, &r);
	r.rlim_cur = limit;
	setrlimit (RLIMIT_DATA, &r);
	#ifdef RLIMIT_RSS
	// Resident set size.
	getrlimit (RLIMIT_RSS, &r);
	r.rlim_cur = limit;
	setrlimit (RLIMIT_RSS, &r);
	#endif
	#ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
	// Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
	// of virtual memory for shadow memory mapping.
	#if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
	// Virtual memory.
	getrlimit (RLIMIT_AS, &r);
	r.rlim_cur = limit;
	setrlimit (RLIMIT_AS, &r);
	#endif
	#endif
	#endif
	}

	bool
	Program::Execute(const Path &path, const char args, const char envp,
	const Path **redirects, unsigned memoryLimit,
	std::string *ErrMsg) {
	// If this OS has posix_spawn and there is no memory limit being implied, use
	// posix_spawn. It is more efficient than fork/exec.
	#ifdef HAVE_POSIX_SPAWN
	if (memoryLimit == 0) {
	posix_spawn_file_actions_t FileActionsStore;
	posix_spawn_file_actions_t *FileActions = 0;

	if (redirects) {
	FileActions = &FileActionsStore;
	posix_spawn_file_actions_init(FileActions);

	// Redirect stdin/stdout.
	if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) \|\|
	RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
	return false;
	if (redirects[1] == 0 \|\| redirects[2] == 0 \|\|
	redirects[1] != redirects[2]) {
	// Just redirect stderr
	if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions)) return false;
	} else {
	// If stdout and stderr should go to the same place, redirect stderr
	// to the FD already open for stdout.
	if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
	return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
	}
	}

	if (!envp)
	#if !defined(__APPLE__)
	envp = const_cast<const char **>(environ);
	#else
	// environ is missing in dylibs.
	envp = const_cast<const char *>(_NSGetEnviron());
	#endif

	// Explicitly initialized to prevent what appears to be a valgrind false
	// positive.
	pid_t PID = 0;
	int Err = posix_spawn(&PID, path.c_str(), FileActions, /attrp/0,
	const_cast<char >(args), const_cast<char >(envp));

	if (FileActions)
	posix_spawn_file_actions_destroy(FileActions);

	if (Err)
	return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);

	Data_ = reinterpret_cast<void*>(PID);
	return true;
	}
	#endif

	// Create a child process.
	int child = fork();
	switch (child) {
	// An error occurred: Return to the caller.
	case -1:
	MakeErrMsg(ErrMsg, "Couldn't fork");
	return false;

	// Child process: Execute the program.
	case 0: {
	// Redirect file descriptors...
	if (redirects) {
	// Redirect stdin
	if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
	// Redirect stdout
	if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
	if (redirects[1] && redirects[2] &&
	(redirects[1]) == (redirects[2])) {
	// If stdout and stderr should go to the same place, redirect stderr
	// to the FD already open for stdout.
	if (-1 == dup2(1,2)) {
	MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
	return false;
	}
	} else {
	// Just redirect stderr
	if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
	}
	}

	// Set memory limits
	if (memoryLimit!=0) {
	SetMemoryLimits(memoryLimit);
	}

	// Execute!
	if (envp != 0)
	execve(path.c_str(),
	const_cast<char **>(args),
	const_cast<char **>(envp));
	else
	execv(path.c_str(),
	const_cast<char **>(args));
	// If the execve() failed, we should exit. Follow Unix protocol and
	// return 127 if the executable was not found, and 126 otherwise.
	// Use _exit rather than exit so that atexit functions and static
	// object destructors cloned from the parent process aren't
	// redundantly run, and so that any data buffered in stdio buffers
	// cloned from the parent aren't redundantly written out.
	_exit(errno == ENOENT ? 127 : 126);
	}

	// Parent process: Break out of the switch to do our processing.
	default:
	break;
	}

	Data_ = reinterpret_cast<void*>(child);

	return true;
	}

	int
	Program::Wait(const sys::Path &path,
	unsigned secondsToWait,
	std::string* ErrMsg)
	{
	#ifdef HAVE_SYS_WAIT_H
	struct sigaction Act, Old;

	if (Data_ == 0) {
	MakeErrMsg(ErrMsg, "Process not started!");
	return -1;
	}

	// Install a timeout handler. The handler itself does nothing, but the simple
	// fact of having a handler at all causes the wait below to return with EINTR,
	// unlike if we used SIG_IGN.
	if (secondsToWait) {
	memset(&Act, 0, sizeof(Act));
	Act.sa_handler = TimeOutHandler;
	sigemptyset(&Act.sa_mask);
	sigaction(SIGALRM, &Act, &Old);
	alarm(secondsToWait);
	}

	// Parent process: Wait for the child process to terminate.
	int status;
	uint64_t pid = reinterpret_cast<uint64_t>(Data_);
	pid_t child = static_cast<pid_t>(pid);
	while (waitpid(pid, &status, 0) != child)
	if (secondsToWait && errno == EINTR) {
	// Kill the child.
	kill(child, SIGKILL);

	// Turn off the alarm and restore the signal handler
	alarm(0);
	sigaction(SIGALRM, &Old, 0);

	// Wait for child to die
	if (wait(&status) != child)
	MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
	else
	MakeErrMsg(ErrMsg, "Child timed out", 0);

	return -2; // Timeout detected
	} else if (errno != EINTR) {
	MakeErrMsg(ErrMsg, "Error waiting for child process");
	return -1;
	}

	// We exited normally without timeout, so turn off the timer.
	if (secondsToWait) {
	alarm(0);
	sigaction(SIGALRM, &Old, 0);
	}

	// Return the proper exit status. Detect error conditions
	// so we can return -1 for them and set ErrMsg informatively.
	int result = 0;
	if (WIFEXITED(status)) {
	result = WEXITSTATUS(status);
	#ifdef HAVE_POSIX_SPAWN
	// The posix_spawn child process returns 127 on any kind of error.
	// Following the POSIX convention for command-line tools (which posix_spawn
	// itself apparently does not), check to see if the failure was due to some
	// reason other than the file not existing, and return 126 in this case.
	bool Exists;
	if (result == 127 && !llvm::sys::fs::exists(path.str(), Exists) && Exists)
	result = 126;
	#endif
	if (result == 127) {
	if (ErrMsg)
	*ErrMsg = llvm::sys::StrError(ENOENT);
	return -1;
	}
	if (result == 126) {
	if (ErrMsg)
	*ErrMsg = "Program could not be executed";
	return -1;
	}
	} else if (WIFSIGNALED(status)) {
	if (ErrMsg) {
	*ErrMsg = strsignal(WTERMSIG(status));
	#ifdef WCOREDUMP
	if (WCOREDUMP(status))
	*ErrMsg += " (core dumped)";
	#endif
	}
	// Return a special value to indicate that the process received an unhandled
	// signal during execution as opposed to failing to execute.
	return -2;
	}
	return result;
	#else
	if (ErrMsg)
	*ErrMsg = "Program::Wait is not implemented on this platform yet!";
	return -1;
	#endif
	}

	error_code Program::ChangeStdinToBinary(){
	// Do nothing, as Unix doesn't differentiate between text and binary.
	return make_error_code(errc::success);
	}

	error_code Program::ChangeStdoutToBinary(){
	// Do nothing, as Unix doesn't differentiate between text and binary.
	return make_error_code(errc::success);
	}

	error_code Program::ChangeStderrToBinary(){
	// Do nothing, as Unix doesn't differentiate between text and binary.
	return make_error_code(errc::success);
	}

	}