Check in LLVM r95781.
diff --git a/lib/System/Unix/Program.inc b/lib/System/Unix/Program.inc
new file mode 100644
index 0000000..e8c2806
--- /dev/null
+++ b/lib/System/Unix/Program.inc
@@ -0,0 +1,331 @@
+//===- llvm/System/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 <llvm/Config/config.h>
+#include "Unix.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
+
+namespace llvm {
+using namespace sys;
+
+Program::Program() : Data_(0) {}
+
+Program::~Program() {}
+
+unsigned Program::GetPid() const {
+  uint64_t pid = reinterpret_cast<uint64_t>(Data_);
+  return static_cast<unsigned>(pid);
+}
+
+// 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 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;
+  std::string File;
+  if (Path->isEmpty())
+    // Redirect empty paths to /dev/null
+    File = "/dev/null";
+  else
+    File = Path->str();
+
+  // Open the file
+  int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
+  if (InFD == -1) {
+    MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
+              + (FD == 0 ? "input" : "output"));
+    return true;
+  }
+
+  // Install it as the requested FD
+  if (-1 == dup2(InFD, FD)) {
+    MakeErrMsg(ErrMsg, "Cannot dup2");
+    return true;
+  }
+  close(InFD);      // Close the original FD
+  return false;
+}
+
+static void TimeOutHandler(int Sig) {
+}
+
+static void SetMemoryLimits (unsigned size)
+{
+#if HAVE_SYS_RESOURCE_H
+  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.
+  // Virtual memory.
+  getrlimit (RLIMIT_AS, &r);
+  r.rlim_cur = limit;
+  setrlimit (RLIMIT_AS, &r);
+#endif
+#endif
+}
+
+bool
+Program::Execute(const Path& path,
+                 const char** args,
+                 const char** envp,
+                 const Path** redirects,
+                 unsigned memoryLimit,
+                 std::string* ErrMsg)
+{
+  if (!path.canExecute()) {
+    if (ErrMsg)
+      *ErrMsg = path.str() + " is not executable";
+    return false;
+  }
+
+  // Create a child process.
+  int child = fork();
+  switch (child) {
+    // An error occured:  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(), (char**)args, (char**)envp);
+      else
+        execv(path.c_str(), (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(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) {
+    Act.sa_sigaction = 0;
+    Act.sa_handler = TimeOutHandler;
+    sigemptyset(&Act.sa_mask);
+    Act.sa_flags = 0;
+    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 -1;   // 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. 0=success, >0 is programs' exit status,
+  // <0 means a signal was returned, -9999999 means the program dumped core.
+  int result = 0;
+  if (WIFEXITED(status))
+    result = WEXITSTATUS(status);
+  else if (WIFSIGNALED(status))
+    result = 0 - WTERMSIG(status);
+#ifdef WCOREDUMP
+  else if (WCOREDUMP(status))
+    result |= 0x01000000;
+#endif
+  return result;
+#else
+  return -99;
+#endif
+
+}
+
+bool
+Program::Kill(std::string* ErrMsg) {
+  if (Data_ == 0) {
+    MakeErrMsg(ErrMsg, "Process not started!");
+    return true;
+  }
+
+  uint64_t pid64 = reinterpret_cast<uint64_t>(Data_);
+  pid_t pid = static_cast<pid_t>(pid64);
+
+  if (kill(pid, SIGKILL) != 0) {
+    MakeErrMsg(ErrMsg, "The process couldn't be killed!");
+    return true;
+  }
+
+  return false;
+}
+
+bool Program::ChangeStdinToBinary(){
+  // Do nothing, as Unix doesn't differentiate between text and binary.
+  return false;
+}
+
+bool Program::ChangeStdoutToBinary(){
+  // Do nothing, as Unix doesn't differentiate between text and binary.
+  return false;
+}
+
+bool Program::ChangeStderrToBinary(){
+  // Do nothing, as Unix doesn't differentiate between text and binary.
+  return false;
+}
+
+}