1 //===- SystemUtils.h - Utilities to do low-level system stuff --*- C++ -*--===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains functions used to do a variety of low-level, often
11 // system-specific, tasks.
13 //===----------------------------------------------------------------------===//
15 #include "Support/SystemUtils.h"
16 #include "Config/sys/types.h"
17 #include "Config/sys/stat.h"
18 #include "Config/fcntl.h"
19 #include "Config/sys/wait.h"
20 #include "Config/unistd.h"
21 #include "Config/config.h"
29 /// isExecutableFile - This function returns true if the filename specified
30 /// exists and is executable.
32 bool llvm::isExecutableFile(const std::string &ExeFileName) {
34 if (stat(ExeFileName.c_str(), &Buf))
35 return false; // Must not be executable!
37 if (!(Buf.st_mode & S_IFREG))
38 return false; // Not a regular file?
40 if (Buf.st_uid == getuid()) // Owner of file?
41 return Buf.st_mode & S_IXUSR;
42 else if (Buf.st_gid == getgid()) // In group of file?
43 return Buf.st_mode & S_IXGRP;
44 else // Unrelated to file?
45 return Buf.st_mode & S_IXOTH;
48 /// isStandardOutAConsole - Return true if we can tell that the standard output
49 /// stream goes to a terminal window or console.
50 bool llvm::isStandardOutAConsole() {
54 // If we don't have isatty, just return false.
59 /// FindExecutable - Find a named executable, giving the argv[0] of program
60 /// being executed. This allows us to find another LLVM tool if it is built
61 /// into the same directory, but that directory is neither the current
62 /// directory, nor in the PATH. If the executable cannot be found, return an
65 std::string llvm::FindExecutable(const std::string &ExeName,
66 const std::string &ProgramPath) {
67 // First check the directory that bugpoint is in. We can do this if
68 // BugPointPath contains at least one / character, indicating that it is a
69 // relative path to bugpoint itself.
71 std::string Result = ProgramPath;
72 while (!Result.empty() && Result[Result.size()-1] != '/')
73 Result.erase(Result.size()-1, 1);
75 if (!Result.empty()) {
77 if (isExecutableFile(Result)) return Result; // Found it?
80 // Okay, if the path to the program didn't tell us anything, try using the
81 // PATH environment variable.
82 const char *PathStr = getenv("PATH");
83 if (PathStr == 0) return "";
85 // Now we have a colon separated list of directories to search... try them...
86 unsigned PathLen = strlen(PathStr);
88 // Find the first colon...
89 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
91 // Check to see if this first directory contains the executable...
92 std::string FilePath = std::string(PathStr, Colon) + '/' + ExeName;
93 if (isExecutableFile(FilePath))
94 return FilePath; // Found the executable!
96 // Nope it wasn't in this directory, check the next range!
97 PathLen -= Colon-PathStr;
99 while (*PathStr == ':') { // Advance past colons
105 // If we fell out, we ran out of directories in PATH to search, return failure
109 static void RedirectFD(const std::string &File, int FD) {
110 if (File.empty()) return; // Noop
113 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
115 std::cerr << "Error opening file '" << File << "' for "
116 << (FD == 0 ? "input" : "output") << "!\n";
120 dup2(InFD, FD); // Install it as the requested FD
121 close(InFD); // Close the original FD
124 /// RunProgramWithTimeout - This function executes the specified program, with
125 /// the specified null-terminated argument array, with the stdin/out/err fd's
126 /// redirected, with a timeout specified on the command line. This terminates
127 /// the calling program if there is an error executing the specified program.
128 /// It returns the return value of the program, or -1 if a timeout is detected.
130 int llvm::RunProgramWithTimeout(const std::string &ProgramPath,
132 const std::string &StdInFile,
133 const std::string &StdOutFile,
134 const std::string &StdErrFile) {
135 // FIXME: install sigalarm handler here for timeout...
137 #ifdef HAVE_SYS_WAIT_H
141 std::cerr << "ERROR forking!\n";
144 RedirectFD(StdInFile, 0); // Redirect file descriptors...
145 RedirectFD(StdOutFile, 1);
146 if (StdOutFile != StdErrFile)
147 RedirectFD(StdErrFile, 2);
151 execv(ProgramPath.c_str(), (char *const *)Args);
152 std::cerr << "Error executing program: '" << ProgramPath;
153 for (; *Args; ++Args)
154 std::cerr << " " << *Args;
161 // Make sure all output has been written while waiting
162 std::cout << std::flush;
165 if (wait(&Status) != Child) {
166 if (errno == EINTR) {
167 static bool FirstTimeout = true;
170 "*** Program execution timed out! This mechanism is designed to handle\n"
171 " programs stuck in infinite loops gracefully. The -timeout option\n"
172 " can be used to change the timeout threshold or disable it completely\n"
173 " (with -timeout=0). This message is only displayed once.\n";
174 FirstTimeout = false;
176 return -1; // Timeout detected
179 std::cerr << "Error waiting for child process!\n";
185 std::cerr << "RunProgramWithTimeout not implemented on this platform!\n";
192 // Function: ExecWait ()
195 // This function executes a program with the specified arguments and
196 // environment. It then waits for the progarm to termiante and then returns
200 // argv - The arguments to the program as an array of C strings. The first
201 // argument should be the name of the program to execute, and the
202 // last argument should be a pointer to NULL.
204 // envp - The environment passes to the program as an array of C strings in
205 // the form of "name=value" pairs. The last element should be a
213 // 1 - The program could not be executed.
214 // 1 - The program returned a non-zero exit status.
215 // 1 - The program terminated abnormally.
218 // The program will inherit the stdin, stdout, and stderr file descriptors
219 // as well as other various configuration settings (umask).
221 // This function should not print anything to stdout/stderr on its own. It is
222 // a generic library function. The caller or executed program should report
223 // errors in the way it sees fit.
225 // This function does not use $PATH to find programs.
227 int llvm::ExecWait(const char * const old_argv[],
228 const char * const old_envp[]) {
229 #ifdef HAVE_SYS_WAIT_H
231 // Create local versions of the parameters that can be passed into execve()
232 // without creating const problems.
234 char ** const argv = (char ** const) old_argv;
235 char ** const envp = (char ** const) old_envp;
237 // Create a child process.
239 // An error occured: Return to the caller.
244 // Child process: Execute the program.
246 execve (argv[0], argv, envp);
247 // If the execve() failed, we should exit and let the parent pick up
248 // our non-zero exit status.
251 // Parent process: Break out of the switch to do our processing.
256 // Parent process: Wait for the child process to termiante.
258 if ((wait (&status)) == -1)
261 // If the program exited normally with a zero exit status, return success!
262 if (WIFEXITED (status) && (WEXITSTATUS(status) == 0))
265 std::cerr << "llvm::ExecWait not implemented on this platform!\n";
268 // Otherwise, return failure.