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//===- SystemUtils.h - Utilities to do low-level system stuff --*- C++ -*--===//
//
// This file contains functions used to do a variety of low-level, often
// system-specific, tasks.
//
//===----------------------------------------------------------------------===//
#include "Support/SystemUtils.h"
#include <algorithm>
#include <fstream>
#include <iostream>
#include <cstdlib>
#include "Config/sys/types.h"
#include "Config/sys/stat.h"
#include "Config/fcntl.h"
#include "Config/sys/wait.h"
#include "Config/unistd.h"
#include "Config/errno.h"
/// isExecutableFile - This function returns true if the filename specified
/// exists and is executable.
///
bool isExecutableFile(const std::string &ExeFileName) {
struct stat Buf;
if (stat(ExeFileName.c_str(), &Buf))
return false; // Must not be executable!
if (!(Buf.st_mode & S_IFREG))
return false; // Not a regular file?
if (Buf.st_uid == getuid()) // Owner of file?
return Buf.st_mode & S_IXUSR;
else if (Buf.st_gid == getgid()) // In group of file?
return Buf.st_mode & S_IXGRP;
else // Unrelated to file?
return Buf.st_mode & S_IXOTH;
}
/// FindExecutable - Find a named executable, giving the argv[0] of program
/// being executed. This allows us to find another LLVM tool if it is built into
/// the same directory, but that directory is neither the current directory, nor
/// in the PATH. If the executable cannot be found, return an empty string.
///
std::string FindExecutable(const std::string &ExeName,
const std::string &ProgramPath) {
// First check the directory that bugpoint is in. We can do this if
// BugPointPath contains at least one / character, indicating that it is a
// relative path to bugpoint itself.
//
std::string Result = ProgramPath;
while (!Result.empty() && Result[Result.size()-1] != '/')
Result.erase(Result.size()-1, 1);
if (!Result.empty()) {
Result += ExeName;
if (isExecutableFile(Result)) return Result; // Found it?
}
// Okay, if the path to the program didn't tell us anything, try using the
// PATH environment variable.
const char *PathStr = getenv("PATH");
if (PathStr == 0) return "";
// 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...
std::string FilePath = std::string(PathStr, Colon) + '/' + ExeName;
if (isExecutableFile(FilePath))
return FilePath; // Found the executable!
// Nope it wasn't in this directory, check the next range!
PathLen -= Colon-PathStr;
PathStr = Colon;
while (*PathStr == ':') { // Advance past colons
PathStr++;
PathLen--;
}
}
// If we fell out, we ran out of directories in PATH to search, return failure
return "";
}
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) {
std::cerr << "Error opening file '" << File << "' for "
<< (FD == 0 ? "input" : "output") << "!\n";
exit(1);
}
dup2(InFD, FD); // Install it as the requested FD
close(InFD); // Close the original FD
}
/// RunProgramWithTimeout - This function executes the specified program, with
/// the specified null-terminated argument array, with the stdin/out/err fd's
/// redirected, with a timeout specified on the commandline. This terminates
/// the calling program if there is an error executing the specified program.
/// It returns the return value of the program, or -1 if a timeout is detected.
///
int RunProgramWithTimeout(const std::string &ProgramPath, const char **Args,
const std::string &StdInFile,
const std::string &StdOutFile,
const std::string &StdErrFile) {
// FIXME: install sigalarm handler here for timeout...
int Child = fork();
switch (Child) {
case -1:
std::cerr << "ERROR forking!\n";
exit(1);
case 0: // Child
RedirectFD(StdInFile, 0); // Redirect file descriptors...
RedirectFD(StdOutFile, 1);
RedirectFD(StdErrFile, 2);
execv(ProgramPath.c_str(), (char *const *)Args);
std::cerr << "Error executing program '" << ProgramPath;
for (; *Args; ++Args)
std::cerr << " " << *Args;
exit(1);
default: break;
}
// Make sure all output has been written while waiting
std::cout << std::flush;
int Status;
if (wait(&Status) != Child) {
if (errno == EINTR) {
static bool FirstTimeout = true;
if (FirstTimeout) {
std::cout <<
"*** Program execution timed out! This mechanism is designed to handle\n"
" programs stuck in infinite loops gracefully. The -timeout option\n"
" can be used to change the timeout threshold or disable it completely\n"
" (with -timeout=0). This message is only displayed once.\n";
FirstTimeout = false;
}
return -1; // Timeout detected
}
std::cerr << "Error waiting for child process!\n";
exit(1);
}
return Status;
}
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