llvm-6502/lib/Support/SystemUtils.cpp

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//===- SystemUtils.cpp - Utilities for low-level system tasks -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains functions used to do a variety of low-level, often
// system-specific, tasks.
//
//===----------------------------------------------------------------------===//
#define _POSIX_MAPPED_FILES
#include "llvm/Support/SystemUtils.h"
#include "llvm/Config/fcntl.h"
#include "llvm/Config/pagesize.h"
#include "llvm/Config/unistd.h"
#include "llvm/Config/windows.h"
#include "llvm/Config/sys/mman.h"
#include "llvm/Config/sys/stat.h"
#include "llvm/Config/sys/types.h"
#include "llvm/Config/sys/wait.h"
#include <algorithm>
#include <cerrno>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <signal.h>
using namespace llvm;
/// isExecutableFile - This function returns true if the filename specified
/// exists and is executable.
///
bool llvm::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;
}
/// isStandardOutAConsole - Return true if we can tell that the standard output
/// stream goes to a terminal window or console.
bool llvm::isStandardOutAConsole() {
#if HAVE_ISATTY
return isatty(1);
#endif
// If we don't have isatty, just return false.
return false;
}
/// 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.
///
#undef FindExecutable // needed on windows :(
std::string llvm::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
}
static bool Timeout = false;
static void TimeOutHandler(int Sig) {
Timeout = true;
}
/// 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 by the last argument. 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 llvm::RunProgramWithTimeout(const std::string &ProgramPath,
const char **Args,
const std::string &StdInFile,
const std::string &StdOutFile,
const std::string &StdErrFile,
unsigned NumSeconds) {
#ifdef HAVE_SYS_WAIT_H
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);
if (StdOutFile != StdErrFile)
RedirectFD(StdErrFile, 2);
else
dup2(1, 2);
execv(ProgramPath.c_str(), (char *const *)Args);
std::cerr << "Error executing program: '" << ProgramPath;
for (; *Args; ++Args)
std::cerr << " " << *Args;
std::cerr << "'\n";
exit(1);
default: break;
}
// Make sure all output has been written while waiting
std::cout << std::flush;
// Install a timeout handler.
Timeout = false;
struct sigaction Act, Old;
Act.sa_sigaction = 0;
Act.sa_handler = TimeOutHandler;
sigemptyset(&Act.sa_mask);
Act.sa_flags = 0;
sigaction(SIGALRM, &Act, &Old);
// Set the timeout if one is set.
if (NumSeconds)
alarm(NumSeconds);
int Status;
while (wait(&Status) != Child)
if (errno == EINTR) {
if (Timeout) {
// Kill the child.
kill(Child, SIGKILL);
if (wait(&Status) != Child)
std::cerr << "Something funny happened waiting for the child!\n";
alarm(0);
sigaction(SIGALRM, &Old, 0);
return -1; // Timeout detected
} else {
std::cerr << "Error waiting for child process!\n";
exit(1);
}
}
alarm(0);
sigaction(SIGALRM, &Old, 0);
return Status;
#else
std::cerr << "RunProgramWithTimeout not implemented on this platform!\n";
return -1;
#endif
}
// ExecWait - executes a program with the specified arguments and environment.
// It then waits for the progarm to termiante and then returns to the caller.
//
// Inputs:
// argv - The arguments to the program as an array of C strings. The first
// argument should be the name of the program to execute, and the
// last argument should be a pointer to NULL.
//
// envp - The environment passes to the program as an array of C strings in
// the form of "name=value" pairs. The last element should be a
// pointer to NULL.
//
// Outputs:
// None.
//
// Return value:
// 0 - No errors.
// 1 - The program could not be executed.
// 1 - The program returned a non-zero exit status.
// 1 - The program terminated abnormally.
//
// Notes:
// The program will inherit the stdin, stdout, and stderr file descriptors
// as well as other various configuration settings (umask).
//
// This function should not print anything to stdout/stderr on its own. It is
// a generic library function. The caller or executed program should report
// errors in the way it sees fit.
//
// This function does not use $PATH to find programs.
//
int llvm::ExecWait(const char * const old_argv[],
const char * const old_envp[]) {
#ifdef HAVE_SYS_WAIT_H
// Create local versions of the parameters that can be passed into execve()
// without creating const problems.
char ** const argv = (char ** const) old_argv;
char ** const envp = (char ** const) old_envp;
// Create a child process.
switch (fork()) {
// An error occured: Return to the caller.
case -1:
return 1;
break;
// Child process: Execute the program.
case 0:
execve (argv[0], argv, envp);
// If the execve() failed, we should exit and let the parent pick up
// our non-zero exit status.
exit (1);
// Parent process: Break out of the switch to do our processing.
default:
break;
}
// Parent process: Wait for the child process to terminate.
int status;
if ((wait (&status)) == -1)
return 1;
// If the program exited normally with a zero exit status, return success!
if (WIFEXITED (status) && (WEXITSTATUS(status) == 0))
return 0;
#else
std::cerr << "llvm::ExecWait not implemented on this platform!\n";
#endif
// Otherwise, return failure.
return 1;
}
/// AllocateRWXMemory - Allocate a slab of memory with read/write/execute
/// permissions. This is typically used for JIT applications where we want
/// to emit code to the memory then jump to it. Getting this type of memory
/// is very OS specific.
///
void *llvm::AllocateRWXMemory(unsigned NumBytes) {
if (NumBytes == 0) return 0;
#if defined(HAVE_WINDOWS_H)
// On windows we use VirtualAlloc.
void *P = VirtualAlloc(0, NumBytes, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
if (P == 0) {
std::cerr << "Error allocating executable memory!\n";
abort();
}
return P;
#elif defined(HAVE_MMAP)
static const long pageSize = GetPageSize();
unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
/* FIXME: This should use the proper autoconf flags */
#if defined(i386) || defined(__i386__) || defined(__x86__)
/* Linux and *BSD tend to have these flags named differently. */
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
# define MAP_ANONYMOUS MAP_ANON
#endif /* defined(MAP_ANON) && !defined(MAP_ANONYMOUS) */
#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
/* nothing */
#else
std::cerr << "This architecture has an unknown MMAP implementation!\n";
abort();
return 0;
#endif
int fd = -1;
#if defined(__linux__)
fd = 0;
#endif
unsigned mmapFlags = MAP_PRIVATE|MAP_ANONYMOUS;
#ifdef MAP_NORESERVE
mmapFlags |= MAP_NORESERVE;
#endif
void *pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
mmapFlags, fd, 0);
if (pa == MAP_FAILED) {
perror("mmap");
abort();
}
return pa;
#else
std::cerr << "Do not know how to allocate mem for the JIT without mmap!\n";
abort();
return 0;
#endif
}