1 //===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Unix specific portion of the Program class.
12 //===----------------------------------------------------------------------===//
14 //===----------------------------------------------------------------------===//
15 //=== WARNING: Implementation here must contain only generic UNIX code that
16 //=== is guaranteed to work on *all* UNIX variants.
17 //===----------------------------------------------------------------------===//
20 #include "llvm/Support/Compiler.h"
21 #include "llvm/Support/FileSystem.h"
22 #include <llvm/Config/config.h>
26 #if HAVE_SYS_RESOURCE_H
27 #include <sys/resource.h>
38 #ifdef HAVE_POSIX_SPAWN
40 #if !defined(__APPLE__)
41 extern char **environ;
43 #include <crt_externs.h> // _NSGetEnviron
50 // This function just uses the PATH environment variable to find the program.
52 sys::FindProgramByName(const std::string& progName) {
54 // Check some degenerate cases
55 if (progName.length() == 0) // no program
57 std::string temp = progName;
58 // Use the given path verbatim if it contains any slashes; this matches
59 // the behavior of sh(1) and friends.
60 if (progName.find('/') != std::string::npos)
63 // At this point, the file name is valid and does not contain slashes. Search
64 // for it through the directories specified in the PATH environment variable.
66 // Get the path. If its empty, we can't do anything to find it.
67 const char *PathStr = getenv("PATH");
71 // Now we have a colon separated list of directories to search; try them.
72 size_t PathLen = strlen(PathStr);
74 // Find the first colon...
75 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
77 // Check to see if this first directory contains the executable...
78 SmallString<128> FilePath(PathStr,Colon);
79 sys::path::append(FilePath, progName);
80 if (sys::fs::can_execute(Twine(FilePath)))
81 return FilePath.str(); // Found the executable!
83 // Nope it wasn't in this directory, check the next path in the list!
84 PathLen -= Colon-PathStr;
87 // Advance past duplicate colons
88 while (*PathStr == ':') {
96 static bool RedirectIO(const StringRef *Path, int FD, std::string* ErrMsg) {
97 if (Path == 0) // Noop
101 // Redirect empty paths to /dev/null
107 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
109 MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
110 + (FD == 0 ? "input" : "output"));
114 // Install it as the requested FD
115 if (dup2(InFD, FD) == -1) {
116 MakeErrMsg(ErrMsg, "Cannot dup2");
120 close(InFD); // Close the original FD
124 #ifdef HAVE_POSIX_SPAWN
125 static bool RedirectIO_PS(const StringRef *Path, int FD, std::string *ErrMsg,
126 posix_spawn_file_actions_t *FileActions) {
127 if (Path == 0) // Noop
131 // Redirect empty paths to /dev/null
136 if (int Err = posix_spawn_file_actions_addopen(
137 FileActions, FD, File.c_str(),
138 FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
139 return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
144 static void TimeOutHandler(int Sig) {
147 static void SetMemoryLimits (unsigned size)
149 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
151 __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
154 getrlimit (RLIMIT_DATA, &r);
156 setrlimit (RLIMIT_DATA, &r);
158 // Resident set size.
159 getrlimit (RLIMIT_RSS, &r);
161 setrlimit (RLIMIT_RSS, &r);
163 #ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
164 // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
165 // of virtual memory for shadow memory mapping.
166 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
168 getrlimit (RLIMIT_AS, &r);
170 setrlimit (RLIMIT_AS, &r);
178 static bool Execute(void **Data, StringRef Program, const char **args,
179 const char **envp, const StringRef **redirects,
180 unsigned memoryLimit, std::string *ErrMsg) {
181 // If this OS has posix_spawn and there is no memory limit being implied, use
182 // posix_spawn. It is more efficient than fork/exec.
183 #ifdef HAVE_POSIX_SPAWN
184 if (memoryLimit == 0) {
185 posix_spawn_file_actions_t FileActionsStore;
186 posix_spawn_file_actions_t *FileActions = 0;
189 FileActions = &FileActionsStore;
190 posix_spawn_file_actions_init(FileActions);
192 // Redirect stdin/stdout.
193 if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) ||
194 RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
196 if (redirects[1] == 0 || redirects[2] == 0 ||
197 *redirects[1] != *redirects[2]) {
198 // Just redirect stderr
199 if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions)) return false;
201 // If stdout and stderr should go to the same place, redirect stderr
202 // to the FD already open for stdout.
203 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
204 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
209 #if !defined(__APPLE__)
210 envp = const_cast<const char **>(environ);
212 // environ is missing in dylibs.
213 envp = const_cast<const char **>(*_NSGetEnviron());
216 // Explicitly initialized to prevent what appears to be a valgrind false
219 int Err = posix_spawn(&PID, Program.str().c_str(), FileActions, /*attrp*/0,
220 const_cast<char **>(args), const_cast<char **>(envp));
223 posix_spawn_file_actions_destroy(FileActions);
226 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
229 *Data = reinterpret_cast<void*>(PID);
234 // Create a child process.
237 // An error occurred: Return to the caller.
239 MakeErrMsg(ErrMsg, "Couldn't fork");
242 // Child process: Execute the program.
244 // Redirect file descriptors...
247 if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
249 if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
250 if (redirects[1] && redirects[2] &&
251 *(redirects[1]) == *(redirects[2])) {
252 // If stdout and stderr should go to the same place, redirect stderr
253 // to the FD already open for stdout.
254 if (-1 == dup2(1,2)) {
255 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
259 // Just redirect stderr
260 if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
265 if (memoryLimit!=0) {
266 SetMemoryLimits(memoryLimit);
270 std::string PathStr = Program;
272 execve(PathStr.c_str(),
273 const_cast<char **>(args),
274 const_cast<char **>(envp));
276 execv(PathStr.c_str(),
277 const_cast<char **>(args));
278 // If the execve() failed, we should exit. Follow Unix protocol and
279 // return 127 if the executable was not found, and 126 otherwise.
280 // Use _exit rather than exit so that atexit functions and static
281 // object destructors cloned from the parent process aren't
282 // redundantly run, and so that any data buffered in stdio buffers
283 // cloned from the parent aren't redundantly written out.
284 _exit(errno == ENOENT ? 127 : 126);
287 // Parent process: Break out of the switch to do our processing.
293 *Data = reinterpret_cast<void*>(child);
298 static int Wait(void *&Data, StringRef Program, unsigned secondsToWait,
299 std::string *ErrMsg) {
300 #ifdef HAVE_SYS_WAIT_H
301 struct sigaction Act, Old;
302 assert(Data && "invalid pid to wait on, process not started?");
304 // Install a timeout handler. The handler itself does nothing, but the simple
305 // fact of having a handler at all causes the wait below to return with EINTR,
306 // unlike if we used SIG_IGN.
308 memset(&Act, 0, sizeof(Act));
309 Act.sa_handler = TimeOutHandler;
310 sigemptyset(&Act.sa_mask);
311 sigaction(SIGALRM, &Act, &Old);
312 alarm(secondsToWait);
315 // Parent process: Wait for the child process to terminate.
317 uint64_t pid = reinterpret_cast<uint64_t>(Data);
318 pid_t child = static_cast<pid_t>(pid);
319 while (waitpid(pid, &status, 0) != child)
320 if (secondsToWait && errno == EINTR) {
322 kill(child, SIGKILL);
324 // Turn off the alarm and restore the signal handler
326 sigaction(SIGALRM, &Old, 0);
328 // Wait for child to die
329 if (wait(&status) != child)
330 MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
332 MakeErrMsg(ErrMsg, "Child timed out", 0);
334 return -2; // Timeout detected
335 } else if (errno != EINTR) {
336 MakeErrMsg(ErrMsg, "Error waiting for child process");
340 // We exited normally without timeout, so turn off the timer.
343 sigaction(SIGALRM, &Old, 0);
346 // Return the proper exit status. Detect error conditions
347 // so we can return -1 for them and set ErrMsg informatively.
349 if (WIFEXITED(status)) {
350 result = WEXITSTATUS(status);
351 #ifdef HAVE_POSIX_SPAWN
352 // The posix_spawn child process returns 127 on any kind of error.
353 // Following the POSIX convention for command-line tools (which posix_spawn
354 // itself apparently does not), check to see if the failure was due to some
355 // reason other than the file not existing, and return 126 in this case.
357 if (result == 127 && !llvm::sys::fs::exists(Program, Exists) && Exists)
362 *ErrMsg = llvm::sys::StrError(ENOENT);
367 *ErrMsg = "Program could not be executed";
370 } else if (WIFSIGNALED(status)) {
372 *ErrMsg = strsignal(WTERMSIG(status));
374 if (WCOREDUMP(status))
375 *ErrMsg += " (core dumped)";
378 // Return a special value to indicate that the process received an unhandled
379 // signal during execution as opposed to failing to execute.
385 *ErrMsg = "Program::Wait is not implemented on this platform yet!";
392 error_code sys::ChangeStdinToBinary(){
393 // Do nothing, as Unix doesn't differentiate between text and binary.
394 return make_error_code(errc::success);
397 error_code sys::ChangeStdoutToBinary(){
398 // Do nothing, as Unix doesn't differentiate between text and binary.
399 return make_error_code(errc::success);
402 error_code sys::ChangeStderrToBinary(){
403 // Do nothing, as Unix doesn't differentiate between text and binary.
404 return make_error_code(errc::success);
407 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
408 static long ArgMax = sysconf(_SC_ARG_MAX);
410 // System says no practical limit.
414 // Conservatively account for space required by environment variables.
417 size_t ArgLength = 0;
418 for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
420 ArgLength += strlen(*I) + 1;
421 if (ArgLength > size_t(ArgMax)) {