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;
39 /// FindExecutable - Find a named executable, giving the argv[0] of program
40 /// being executed. This allows us to find another LLVM tool if it is built
41 /// into the same directory, but that directory is neither the current
42 /// directory, nor in the PATH. If the executable cannot be found, return an
45 std::string FindExecutable(const std::string &ExeName,
46 const std::string &ProgramPath) {
47 // First check the directory that bugpoint is in. We can do this if
48 // BugPointPath contains at least one / character, indicating that it is a
49 // relative path to bugpoint itself.
51 std::string Result = ProgramPath;
52 while (!Result.empty() && Result[Result.size()-1] != '/')
53 Result.erase(Result.size()-1, 1);
55 if (!Result.empty()) {
57 if (isExecutableFile(Result)) return Result; // Found it?
60 // Okay, if the path to the program didn't tell us anything, try using the
61 // PATH environment variable.
62 const char *PathStr = getenv("PATH");
63 if (PathStr == 0) return "";
65 // Now we have a colon separated list of directories to search... try them...
66 unsigned PathLen = strlen(PathStr);
68 // Find the first colon...
69 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
71 // Check to see if this first directory contains the executable...
72 std::string FilePath = std::string(PathStr, Colon) + '/' + ExeName;
73 if (isExecutableFile(FilePath))
74 return FilePath; // Found the executable!
76 // Nope it wasn't in this directory, check the next range!
77 PathLen -= Colon-PathStr;
79 while (*PathStr == ':') { // Advance past colons
85 // If we fell out, we ran out of directories in PATH to search, return failure
89 static void RedirectFD(const std::string &File, int FD) {
90 if (File.empty()) return; // Noop
93 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
95 std::cerr << "Error opening file '" << File << "' for "
96 << (FD == 0 ? "input" : "output") << "!\n";
100 dup2(InFD, FD); // Install it as the requested FD
101 close(InFD); // Close the original FD
104 /// RunProgramWithTimeout - This function executes the specified program, with
105 /// the specified null-terminated argument array, with the stdin/out/err fd's
106 /// redirected, with a timeout specified on the command line. This terminates
107 /// the calling program if there is an error executing the specified program.
108 /// It returns the return value of the program, or -1 if a timeout is detected.
110 int RunProgramWithTimeout(const std::string &ProgramPath, const char **Args,
111 const std::string &StdInFile,
112 const std::string &StdOutFile,
113 const std::string &StdErrFile) {
115 // FIXME: install sigalarm handler here for timeout...
120 std::cerr << "ERROR forking!\n";
123 RedirectFD(StdInFile, 0); // Redirect file descriptors...
124 RedirectFD(StdOutFile, 1);
125 RedirectFD(StdErrFile, 2);
127 execv(ProgramPath.c_str(), (char *const *)Args);
128 std::cerr << "Error executing program '" << ProgramPath;
129 for (; *Args; ++Args)
130 std::cerr << " " << *Args;
136 // Make sure all output has been written while waiting
137 std::cout << std::flush;
140 if (wait(&Status) != Child) {
141 if (errno == EINTR) {
142 static bool FirstTimeout = true;
145 "*** Program execution timed out! This mechanism is designed to handle\n"
146 " programs stuck in infinite loops gracefully. The -timeout option\n"
147 " can be used to change the timeout threshold or disable it completely\n"
148 " (with -timeout=0). This message is only displayed once.\n";
149 FirstTimeout = false;
151 return -1; // Timeout detected
154 std::cerr << "Error waiting for child process!\n";
162 // Function: ExecWait ()
165 // This function executes a program with the specified arguments and
166 // environment. It then waits for the progarm to termiante and then returns
170 // argv - The arguments to the program as an array of C strings. The first
171 // argument should be the name of the program to execute, and the
172 // last argument should be a pointer to NULL.
174 // envp - The environment passes to the program as an array of C strings in
175 // the form of "name=value" pairs. The last element should be a
183 // 1 - The program could not be executed.
184 // 1 - The program returned a non-zero exit status.
185 // 1 - The program terminated abnormally.
188 // The program will inherit the stdin, stdout, and stderr file descriptors
189 // as well as other various configuration settings (umask).
191 // This function should not print anything to stdout/stderr on its own. It is
192 // a generic library function. The caller or executed program should report
193 // errors in the way it sees fit.
195 // This function does not use $PATH to find programs.
198 ExecWait (const char * const old_argv[], const char * const old_envp[])
203 // Status from child process when it exits
207 // Create local versions of the parameters that can be passed into execve()
208 // without creating const problems.
210 char ** const argv = (char ** const) old_argv;
211 char ** const envp = (char ** const) old_envp;
214 // Create a child process.
216 switch (child=fork())
219 // An error occured: Return to the caller.
226 // Child process: Execute the program.
229 execve (argv[0], argv, envp);
232 // If the execve() failed, we should exit and let the parent pick up
233 // our non-zero exit status.
239 // Parent process: Break out of the switch to do our processing.
246 // Parent process: Wait for the child process to termiante.
248 if ((wait (&status)) == -1)
254 // If the program exited normally with a zero exit status, return success!
256 if (WIFEXITED (status) && (WEXITSTATUS(status) == 0))
262 // Otherwise, return failure.