1 //===- SystemUtils.h - Utilities to do low-level system stuff --*- C++ -*--===//
3 // This file contains functions used to do a variety of low-level, often
4 // system-specific, tasks.
6 //===----------------------------------------------------------------------===//
8 #include "Support/SystemUtils.h"
13 #include "Config/sys/types.h"
14 #include "Config/sys/stat.h"
15 #include "Config/fcntl.h"
16 #include "Config/sys/wait.h"
17 #include "Config/unistd.h"
18 #include "Config/errno.h"
20 /// isExecutableFile - This function returns true if the filename specified
21 /// exists and is executable.
23 bool isExecutableFile(const std::string &ExeFileName) {
25 if (stat(ExeFileName.c_str(), &Buf))
26 return false; // Must not be executable!
28 if (!(Buf.st_mode & S_IFREG))
29 return false; // Not a regular file?
31 if (Buf.st_uid == getuid()) // Owner of file?
32 return Buf.st_mode & S_IXUSR;
33 else if (Buf.st_gid == getgid()) // In group of file?
34 return Buf.st_mode & S_IXGRP;
35 else // Unrelated to file?
36 return Buf.st_mode & S_IXOTH;
40 // FindExecutable - Find a named executable, giving the argv[0] of bugpoint.
41 // This assumes the executable is in the same directory as bugpoint itself.
42 // If the executable cannot be found, return an empty string.
44 std::string FindExecutable(const std::string &ExeName,
45 const std::string &BugPointPath) {
46 // First check the directory that bugpoint is in. We can do this if
47 // BugPointPath contains at least one / character, indicating that it is a
48 // relative path to bugpoint itself.
50 std::string Result = BugPointPath;
51 while (!Result.empty() && Result[Result.size()-1] != '/')
52 Result.erase(Result.size()-1, 1);
54 if (!Result.empty()) {
56 if (isExecutableFile(Result)) return Result; // Found it?
59 // Okay, if the path to bugpoint didn't tell us anything, try using the PATH
60 // environment variable.
61 const char *PathStr = getenv("PATH");
62 if (PathStr == 0) return "";
64 // Now we have a colon separated list of directories to search... try them...
65 unsigned PathLen = strlen(PathStr);
67 // Find the first colon...
68 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
70 // Check to see if this first directory contains the executable...
71 std::string FilePath = std::string(PathStr, Colon) + '/' + ExeName;
72 if (isExecutableFile(FilePath))
73 return FilePath; // Found the executable!
75 // Nope it wasn't in this directory, check the next range!
76 PathLen -= Colon-PathStr;
78 while (*PathStr == ':') { // Advance past colons
84 // If we fell out, we ran out of directories in PATH to search, return failure
88 static void RedirectFD(const std::string &File, int FD) {
89 if (File.empty()) return; // Noop
92 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
94 std::cerr << "Error opening file '" << File << "' for "
95 << (FD == 0 ? "input" : "output") << "!\n";
99 dup2(InFD, FD); // Install it as the requested FD
100 close(InFD); // Close the original FD
103 /// RunProgramWithTimeout - This function executes the specified program, with
104 /// the specified null-terminated argument array, with the stdin/out/err fd's
105 /// redirected, with a timeout specified on the commandline. This terminates
106 /// the calling program if there is an error executing the specified program.
107 /// It returns the return value of the program, or -1 if a timeout is detected.
109 int RunProgramWithTimeout(const std::string &ProgramPath, const char **Args,
110 const std::string &StdInFile,
111 const std::string &StdOutFile,
112 const std::string &StdErrFile) {
114 // FIXME: install sigalarm handler here for timeout...
119 std::cerr << "ERROR forking!\n";
122 RedirectFD(StdInFile, 0); // Redirect file descriptors...
123 RedirectFD(StdOutFile, 1);
124 RedirectFD(StdErrFile, 2);
126 execv(ProgramPath.c_str(), (char *const *)Args);
127 std::cerr << "Error executing program '" << ProgramPath;
128 for (; *Args; ++Args)
129 std::cerr << " " << *Args;
135 // Make sure all output has been written while waiting
136 std::cout << std::flush;
139 if (wait(&Status) != Child) {
140 if (errno == EINTR) {
141 static bool FirstTimeout = true;
144 "*** Program execution timed out! This mechanism is designed to handle\n"
145 " programs stuck in infinite loops gracefully. The -timeout option\n"
146 " can be used to change the timeout threshold or disable it completely\n"
147 " (with -timeout=0). This message is only displayed once.\n";
148 FirstTimeout = false;
150 return -1; // Timeout detected
153 std::cerr << "Error waiting for child process!\n";