path: root/lib/System/Win32/Program.inc

//===- Win32/Program.cpp - Win32 Program Implementation ------- -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 specific implementation of the Program class.
//
//===----------------------------------------------------------------------===//

#include "Win32.h"
#include <cstdio>
#include <malloc.h>
#include <io.h>
#include <fcntl.h>

//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code
//===          and must not be UNIX code
//===----------------------------------------------------------------------===//

namespace llvm {
using namespace sys;

// 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();
  if (temp.canExecute()) // already executable as is
    return temp;

  // At this point, the file name is valid and its not executable.
  // Let Windows search for it.
  char buffer[MAX_PATH];
  char *dummy = NULL;
  DWORD len = SearchPath(NULL, progName.c_str(), ".exe", MAX_PATH,
                         buffer, &dummy);

  // See if it wasn't found.
  if (len == 0)
    return Path();

  // See if we got the entire path.
  if (len < MAX_PATH)
    return Path(buffer);

  // Buffer was too small; grow and retry.
  while (true) {
    char *b = reinterpret_cast<char *>(_alloca(len+1));
    DWORD len2 = SearchPath(NULL, progName.c_str(), ".exe", len+1, b, &dummy);

    // It is unlikely the search failed, but it's always possible some file
    // was added or removed since the last search, so be paranoid...
    if (len2 == 0)
      return Path();
    else if (len2 <= len)
      return Path(b);

    len = len2;
  }
}

static HANDLE RedirectIO(const Path *path, int fd, std::string* ErrMsg) {
  HANDLE h;
  if (path == 0) {
    DuplicateHandle(GetCurrentProcess(), (HANDLE)_get_osfhandle(fd),
                    GetCurrentProcess(), &h,
                    0, TRUE, DUPLICATE_SAME_ACCESS);
    return h;
  }

  const char *fname;
  if (path->isEmpty())
    fname = "NUL";
  else
    fname = path->toString().c_str();

  SECURITY_ATTRIBUTES sa;
  sa.nLength = sizeof(sa);
  sa.lpSecurityDescriptor = 0;
  sa.bInheritHandle = TRUE;

  h = CreateFile(fname, fd ? GENERIC_WRITE : GENERIC_READ, FILE_SHARE_READ,
                 &sa, fd == 0 ? OPEN_EXISTING : CREATE_ALWAYS,
                 FILE_ATTRIBUTE_NORMAL, NULL);
  if (h == INVALID_HANDLE_VALUE) {
    MakeErrMsg(ErrMsg, std::string(fname) + ": Can't open file for " +
        (fd ? "input: " : "output: "));
  }

  return h;
}

#ifdef __MINGW32__
  // Due to unknown reason, mingw32's w32api doesn't have this declaration.
  extern "C"
  BOOL WINAPI SetInformationJobObject(HANDLE hJob,
                                      JOBOBJECTINFOCLASS JobObjectInfoClass,
                                      LPVOID lpJobObjectInfo,
                                      DWORD cbJobObjectInfoLength);
#endif

int
Program::ExecuteAndWait(const Path& path,
                        const char** args,
                        const char** envp,
                        const Path** redirects,
                        unsigned secondsToWait,
                        unsigned memoryLimit,
                        std::string* ErrMsg) {
  if (!path.canExecute()) {
    if (ErrMsg)
      *ErrMsg = "program not executable";
    return -1;
  }

  // Windows wants a command line, not an array of args, to pass to the new
  // process.  We have to concatenate them all, while quoting the args that
  // have embedded spaces.

  // First, determine the length of the command line.
  unsigned len = 0;
  for (unsigned i = 0; args[i]; i++) {
    len += strlen(args[i]) + 1;
    if (strchr(args[i], ' '))
      len += 2;
  }

  // Now build the command line.
  char *command = reinterpret_cast<char *>(_alloca(len+1));
  char *p = command;

  for (unsigned i = 0; args[i]; i++) {
    const char *arg = args[i];
    size_t len = strlen(arg);
    bool needsQuoting = strchr(arg, ' ') != 0;
    if (needsQuoting)
      *p++ = '"';
    memcpy(p, arg, len);
    p += len;
    if (needsQuoting)
      *p++ = '"';
    *p++ = ' ';
  }

  *p = 0;

  // The pointer to the environment block for the new process.
  char *envblock = 0;

  if (envp) {
    // An environment block consists of a null-terminated block of
    // null-terminated strings. Convert the array of environment variables to
    // an environment block by concatenating them.

    // First, determine the length of the environment block.
    len = 0;
    for (unsigned i = 0; envp[i]; i++)
      len += strlen(envp[i]) + 1;

    // Now build the environment block.
    envblock = reinterpret_cast<char *>(_alloca(len+1));
    p = envblock;

    for (unsigned i = 0; envp[i]; i++) {
      const char *ev = envp[i];
      size_t len = strlen(ev) + 1;
      memcpy(p, ev, len);
      p += len;
    }

    *p = 0;
  }

  // Create a child process.
  STARTUPINFO si;
  memset(&si, 0, sizeof(si));
  si.cb = sizeof(si);
  si.hStdInput = INVALID_HANDLE_VALUE;
  si.hStdOutput = INVALID_HANDLE_VALUE;
  si.hStdError = INVALID_HANDLE_VALUE;

  if (redirects) {
    si.dwFlags = STARTF_USESTDHANDLES;

    si.hStdInput = RedirectIO(redirects[0], 0, ErrMsg);
    if (si.hStdInput == INVALID_HANDLE_VALUE) {
      MakeErrMsg(ErrMsg, "can't redirect stdin");
      return -1;
    }
    si.hStdOutput = RedirectIO(redirects[1], 1, ErrMsg);
    if (si.hStdOutput == INVALID_HANDLE_VALUE) {
      CloseHandle(si.hStdInput);
      MakeErrMsg(ErrMsg, "can't redirect stdout");
      return -1;
    }
    if (redirects[1] && redirects[2] && *(redirects[1]) == *(redirects[2])) {
      // If stdout and stderr should go to the same place, redirect stderr
      // to the handle already open for stdout.
      DuplicateHandle(GetCurrentProcess(), si.hStdOutput,
                      GetCurrentProcess(), &si.hStdError,
                      0, TRUE, DUPLICATE_SAME_ACCESS);
    } else {
      // Just redirect stderr
      si.hStdError = RedirectIO(redirects[2], 2, ErrMsg);
      if (si.hStdError == INVALID_HANDLE_VALUE) {
        CloseHandle(si.hStdInput);