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//===- llvm/System/Unix/Program.cpp -----------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and 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"
#include <iostream>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SIGNAL_H
#include <signal.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
extern char** environ;
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.setFile(progName)) // invalid name
return Path();
// FIXME: have to check for absolute filename - we cannot assume anything
// about "." being in $PATH
if (temp.canExecute()) // already executable as is
return temp;
// At this point, the file name is valid and its not executable
// 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.
unsigned 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.setDirectory(std::string(PathStr,Colon))) {
FilePath.appendFile(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 void RedirectFD(const std::string &File, int FD) {
if (File.empty()) return; // Noop
// Open the file
int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
if (InFD == -1) {
ThrowErrno("Cannot open file '" + File + "' for "
+ (FD == 0 ? "input" : "output") + "!\n");
}
dup2(InFD, FD); // Install it as the requested FD
close(InFD); // Close the original FD
}
static bool Timeout = false;
static void TimeOutHandler(int Sig) {
Timeout = true;
}
int
Program::ExecuteAndWait(const Path& path,
const char** args,
const char** envp,
const Path** redirects,
unsigned secondsToWait
) {
if (!path.canExecute())
throw path.toString() + " is not executable";
#ifdef HAVE_SYS_WAIT_H
// Create a child process.
int child = fork();
switch (child) {
// An error occured: Return to the caller.
case -1:
ThrowErrno(std::string("Couldn't execute program '") + path.toString() +
"'");
break;
// Child process: Execute the program.
case 0: {
// Redirect file descriptors...
if (redirects) {
if (redirects[0])
if (redirects[0]->isEmpty())
RedirectFD("/dev/null",0);
else
RedirectFD(redirects[0]->toString(), 0);
if (redirects[1])
if (redirects[1]->isEmpty())
RedirectFD("/dev/null",1);
else
RedirectFD(redirects[1]->toString(), 1);
if (redirects[1] && redirects[2] &&
*(redirects[1]) != *(redirects[2])) {
if (redirects[2]->isEmpty())
RedirectFD("/dev/null",2);
else
RedirectFD(redirects[2]->toString(), 2);
} else {
dup2(1, 2);
}
}
// Set up the environment
char** env = environ;
if (envp != 0)
env = (char**) envp;
// Execute!
execve (path.c_str(), (char** const)args, env);
// If the execve() failed, we should exit and let the parent pick up
// our non-zero exit status.
exit (errno);
}
// Parent process: Break out of the switch to do our processing.
default:
break;
}
// Make sure stderr and stdout have been flushed
std::cerr << std::flush;
std::cout << std::flush;
fsync(1);
fsync(2);
struct sigaction Act, Old;
// Install a timeout handler.
if (secondsToWait) {
Timeout = false;
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;
while (wait(&status) != 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)
ThrowErrno("Child timedout but wouldn't die");
return -1; // Timeout detected
} else {
ThrowErrno("Error waiting for child process");
}
// We exited normally without timeout, so turn off the timer.
if (secondsToWait) {
alarm(0);
sigaction(SIGALRM, &Old, 0);
}
// If the program exited normally with a zero exit status, return success!
if (WIFEXITED (status))
return WEXITSTATUS(status);
else if (WIFSIGNALED(status))
return 1;
#else
throw std::string(
"Program::ExecuteAndWait not implemented on this platform!\n");
#endif
return 0;
}
}
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