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1 : //===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
2 : //
3 : // The LLVM Compiler Infrastructure
4 : //
5 : // This file is distributed under the University of Illinois Open Source
6 : // License. See LICENSE.TXT for details.
7 : //
8 : //===----------------------------------------------------------------------===//
9 : //
10 : // This file implements the Unix specific portion of the Program class.
11 : //
12 : //===----------------------------------------------------------------------===//
13 :
14 : //===----------------------------------------------------------------------===//
15 : //=== WARNING: Implementation here must contain only generic UNIX code that
16 : //=== is guaranteed to work on *all* UNIX variants.
17 : //===----------------------------------------------------------------------===//
18 :
19 : #include "Unix.h"
20 : #include "llvm/ADT/StringExtras.h"
21 : #include "llvm/Config/config.h"
22 : #include "llvm/Support/Compiler.h"
23 : #include "llvm/Support/Errc.h"
24 : #include "llvm/Support/FileSystem.h"
25 : #include "llvm/Support/Path.h"
26 : #include "llvm/Support/StringSaver.h"
27 : #include "llvm/Support/raw_ostream.h"
28 : #if HAVE_SYS_STAT_H
29 : #include <sys/stat.h>
30 : #endif
31 : #if HAVE_SYS_RESOURCE_H
32 : #include <sys/resource.h>
33 : #endif
34 : #if HAVE_SIGNAL_H
35 : #include <signal.h>
36 : #endif
37 : #if HAVE_FCNTL_H
38 : #include <fcntl.h>
39 : #endif
40 : #if HAVE_UNISTD_H
41 : #include <unistd.h>
42 : #endif
43 : #ifdef HAVE_POSIX_SPAWN
44 : #include <spawn.h>
45 :
46 : #if defined(__APPLE__)
47 : #include <TargetConditionals.h>
48 : #endif
49 :
50 : #if defined(__APPLE__) && !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE)
51 : #define USE_NSGETENVIRON 1
52 : #else
53 : #define USE_NSGETENVIRON 0
54 : #endif
55 :
56 : #if !USE_NSGETENVIRON
57 : extern char **environ;
58 : #else
59 : #include <crt_externs.h> // _NSGetEnviron
60 : #endif
61 : #endif
62 :
63 : namespace llvm {
64 :
65 : using namespace sys;
66 :
67 2898378 : ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
68 :
69 50060 : ErrorOr<std::string> sys::findProgramByName(StringRef Name,
70 : ArrayRef<StringRef> Paths) {
71 : assert(!Name.empty() && "Must have a name!");
72 : // Use the given path verbatim if it contains any slashes; this matches
73 : // the behavior of sh(1) and friends.
74 50060 : if (Name.find('/') != StringRef::npos)
75 4865 : return std::string(Name);
76 :
77 : SmallVector<StringRef, 16> EnvironmentPaths;
78 45195 : if (Paths.empty())
79 45194 : if (const char *PathEnv = std::getenv("PATH")) {
80 45190 : SplitString(PathEnv, EnvironmentPaths, ":");
81 : Paths = EnvironmentPaths;
82 : }
83 :
84 261243 : for (auto Path : Paths) {
85 225357 : if (Path.empty())
86 0 : continue;
87 :
88 : // Check to see if this first directory contains the executable...
89 : SmallString<128> FilePath(Path);
90 225357 : sys::path::append(FilePath, Name);
91 225357 : if (sys::fs::can_execute(FilePath.c_str()))
92 9309 : return std::string(FilePath.str()); // Found the executable!
93 : }
94 : return errc::no_such_file_or_directory;
95 : }
96 :
97 0 : static bool RedirectIO(Optional<StringRef> Path, int FD, std::string* ErrMsg) {
98 0 : if (!Path) // Noop
99 : return false;
100 : std::string File;
101 0 : if (Path->empty())
102 : // Redirect empty paths to /dev/null
103 : File = "/dev/null";
104 : else
105 0 : File = *Path;
106 :
107 : // Open the file
108 0 : int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
109 0 : if (InFD == -1) {
110 0 : MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
111 0 : + (FD == 0 ? "input" : "output"));
112 0 : return true;
113 : }
114 :
115 : // Install it as the requested FD
116 0 : if (dup2(InFD, FD) == -1) {
117 0 : MakeErrMsg(ErrMsg, "Cannot dup2");
118 0 : close(InFD);
119 0 : return true;
120 : }
121 0 : close(InFD); // Close the original FD
122 0 : return false;
123 : }
124 :
125 : #ifdef HAVE_POSIX_SPAWN
126 48 : static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
127 : posix_spawn_file_actions_t *FileActions) {
128 48 : if (!Path) // Noop
129 : return false;
130 : const char *File;
131 31 : if (Path->empty())
132 : // Redirect empty paths to /dev/null
133 : File = "/dev/null";
134 : else
135 : File = Path->c_str();
136 :
137 56 : if (int Err = posix_spawn_file_actions_addopen(
138 : FileActions, FD, File,
139 : FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
140 0 : return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
141 : return false;
142 : }
143 : #endif
144 :
145 1 : static void TimeOutHandler(int Sig) {
146 1 : }
147 :
148 0 : static void SetMemoryLimits(unsigned size) {
149 : #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
150 : struct rlimit r;
151 0 : __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
152 :
153 : // Heap size
154 0 : getrlimit (RLIMIT_DATA, &r);
155 0 : r.rlim_cur = limit;
156 0 : setrlimit (RLIMIT_DATA, &r);
157 : #ifdef RLIMIT_RSS
158 : // Resident set size.
159 0 : getrlimit (RLIMIT_RSS, &r);
160 0 : r.rlim_cur = limit;
161 0 : setrlimit (RLIMIT_RSS, &r);
162 : #endif
163 : #endif
164 0 : }
165 :
166 : }
167 :
168 : static std::vector<const char *>
169 19307 : toNullTerminatedCStringArray(ArrayRef<StringRef> Strings, StringSaver &Saver) {
170 : std::vector<const char *> Result;
171 994323 : for (StringRef S : Strings)
172 975016 : Result.push_back(Saver.save(S).data());
173 19307 : Result.push_back(nullptr);
174 19307 : return Result;
175 : }
176 :
177 0 : static bool Execute(ProcessInfo &PI, StringRef Program,
178 : ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
179 : ArrayRef<Optional<StringRef>> Redirects,
180 : unsigned MemoryLimit, std::string *ErrMsg) {
181 0 : if (!llvm::sys::fs::exists(Program)) {
182 0 : if (ErrMsg)
183 0 : *ErrMsg = std::string("Executable \"") + Program.str() +
184 0 : std::string("\" doesn't exist!");
185 0 : return false;
186 : }
187 :
188 0 : BumpPtrAllocator Allocator;
189 : StringSaver Saver(Allocator);
190 : std::vector<const char *> ArgVector, EnvVector;
191 : const char **Argv = nullptr;
192 : const char **Envp = nullptr;
193 0 : ArgVector = toNullTerminatedCStringArray(Args, Saver);
194 0 : Argv = ArgVector.data();
195 0 : if (Env) {
196 0 : EnvVector = toNullTerminatedCStringArray(*Env, Saver);
197 0 : Envp = EnvVector.data();
198 : }
199 :
200 : // If this OS has posix_spawn and there is no memory limit being implied, use
201 : // posix_spawn. It is more efficient than fork/exec.
202 : #ifdef HAVE_POSIX_SPAWN
203 0 : if (MemoryLimit == 0) {
204 : posix_spawn_file_actions_t FileActionsStore;
205 : posix_spawn_file_actions_t *FileActions = nullptr;
206 :
207 : // If we call posix_spawn_file_actions_addopen we have to make sure the
208 : // c strings we pass to it stay alive until the call to posix_spawn,
209 : // so we copy any StringRefs into this variable.
210 0 : std::string RedirectsStorage[3];
211 :
212 0 : if (!Redirects.empty()) {
213 : assert(Redirects.size() == 3);
214 0 : std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
215 0 : for (int I = 0; I < 3; ++I) {
216 0 : if (Redirects[I]) {
217 0 : RedirectsStorage[I] = *Redirects[I];
218 0 : RedirectsStr[I] = &RedirectsStorage[I];
219 : }
220 : }
221 :
222 : FileActions = &FileActionsStore;
223 0 : posix_spawn_file_actions_init(FileActions);
224 :
225 : // Redirect stdin/stdout.
226 0 : if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
227 0 : RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
228 0 : return false;
229 0 : if (!Redirects[1] || !Redirects[2] || *Redirects[1] != *Redirects[2]) {
230 : // Just redirect stderr
231 0 : if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
232 0 : return false;
233 : } else {
234 : // If stdout and stderr should go to the same place, redirect stderr
235 : // to the FD already open for stdout.
236 0 : if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
237 0 : return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
238 : }
239 : }
240 :
241 0 : if (!Envp)
242 : #if !USE_NSGETENVIRON
243 0 : Envp = const_cast<const char **>(environ);
244 : #else
245 : // environ is missing in dylibs.
246 : Envp = const_cast<const char **>(*_NSGetEnviron());
247 : #endif
248 :
249 : // Explicitly initialized to prevent what appears to be a valgrind false
250 : // positive.
251 0 : pid_t PID = 0;
252 0 : int Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
253 : /*attrp*/ nullptr, const_cast<char **>(Argv),
254 : const_cast<char **>(Envp));
255 :
256 0 : if (FileActions)
257 0 : posix_spawn_file_actions_destroy(FileActions);
258 :
259 0 : if (Err)
260 0 : return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
261 :
262 0 : PI.Pid = PID;
263 0 : PI.Process = PID;
264 :
265 0 : return true;
266 : }
267 : #endif
268 :
269 : // Create a child process.
270 0 : int child = fork();
271 0 : switch (child) {
272 : // An error occurred: Return to the caller.
273 : case -1:
274 0 : MakeErrMsg(ErrMsg, "Couldn't fork");
275 0 : return false;
276 :
277 : // Child process: Execute the program.
278 0 : case 0: {
279 : // Redirect file descriptors...
280 0 : if (!Redirects.empty()) {
281 : // Redirect stdin
282 0 : if (RedirectIO(Redirects[0], 0, ErrMsg)) { return false; }
283 : // Redirect stdout
284 0 : if (RedirectIO(Redirects[1], 1, ErrMsg)) { return false; }
285 0 : if (Redirects[1] && Redirects[2] && *Redirects[1] == *Redirects[2]) {
286 : // If stdout and stderr should go to the same place, redirect stderr
287 : // to the FD already open for stdout.
288 0 : if (-1 == dup2(1,2)) {
289 0 : MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
290 0 : return false;
291 : }
292 : } else {
293 : // Just redirect stderr
294 0 : if (RedirectIO(Redirects[2], 2, ErrMsg)) { return false; }
295 : }
296 : }
297 :
298 : // Set memory limits
299 : if (MemoryLimit!=0) {
300 0 : SetMemoryLimits(MemoryLimit);
301 : }
302 :
303 : // Execute!
304 : std::string PathStr = Program;
305 0 : if (Envp != nullptr)
306 0 : execve(PathStr.c_str(), const_cast<char **>(Argv),
307 : const_cast<char **>(Envp));
308 : else
309 0 : execv(PathStr.c_str(), const_cast<char **>(Argv));
310 : // If the execve() failed, we should exit. Follow Unix protocol and
311 : // return 127 if the executable was not found, and 126 otherwise.
312 : // Use _exit rather than exit so that atexit functions and static
313 : // object destructors cloned from the parent process aren't
314 : // redundantly run, and so that any data buffered in stdio buffers
315 : // cloned from the parent aren't redundantly written out.
316 0 : _exit(errno == ENOENT ? 127 : 126);
317 : }
318 :
319 : // Parent process: Break out of the switch to do our processing.
320 : default:
321 : break;
322 : }
323 :
324 0 : PI.Pid = child;
325 0 : PI.Process = child;
326 :
327 0 : return true;
328 : }
329 :
330 : namespace llvm {
331 :
332 2879072 : ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
333 : bool WaitUntilTerminates, std::string *ErrMsg) {
334 : struct sigaction Act, Old;
335 : assert(PI.Pid && "invalid pid to wait on, process not started?");
336 :
337 : int WaitPidOptions = 0;
338 2879072 : pid_t ChildPid = PI.Pid;
339 2879072 : if (WaitUntilTerminates) {
340 : SecondsToWait = 0;
341 2859936 : } else if (SecondsToWait) {
342 : // Install a timeout handler. The handler itself does nothing, but the
343 : // simple fact of having a handler at all causes the wait below to return
344 : // with EINTR, unlike if we used SIG_IGN.
345 166 : memset(&Act, 0, sizeof(Act));
346 166 : Act.sa_handler = TimeOutHandler;
347 166 : sigemptyset(&Act.sa_mask);
348 166 : sigaction(SIGALRM, &Act, &Old);
349 166 : alarm(SecondsToWait);
350 : } else if (SecondsToWait == 0)
351 : WaitPidOptions = WNOHANG;
352 :
353 : // Parent process: Wait for the child process to terminate.
354 : int status;
355 2879072 : ProcessInfo WaitResult;
356 :
357 : do {
358 2879072 : WaitResult.Pid = waitpid(ChildPid, &status, WaitPidOptions);
359 2879072 : } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
360 :
361 2879072 : if (WaitResult.Pid != PI.Pid) {
362 2859770 : if (WaitResult.Pid == 0) {
363 : // Non-blocking wait.
364 2859769 : return WaitResult;
365 : } else {
366 1 : if (SecondsToWait && errno == EINTR) {
367 : // Kill the child.
368 1 : kill(PI.Pid, SIGKILL);
369 :
370 : // Turn off the alarm and restore the signal handler
371 1 : alarm(0);
372 1 : sigaction(SIGALRM, &Old, nullptr);
373 :
374 : // Wait for child to die
375 1 : if (wait(&status) != ChildPid)
376 0 : MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
377 : else
378 2 : MakeErrMsg(ErrMsg, "Child timed out", 0);
379 :
380 1 : WaitResult.ReturnCode = -2; // Timeout detected
381 1 : return WaitResult;
382 0 : } else if (errno != EINTR) {
383 0 : MakeErrMsg(ErrMsg, "Error waiting for child process");
384 0 : WaitResult.ReturnCode = -1;
385 0 : return WaitResult;
386 : }
387 : }
388 : }
389 :
390 : // We exited normally without timeout, so turn off the timer.
391 19302 : if (SecondsToWait && !WaitUntilTerminates) {
392 165 : alarm(0);
393 165 : sigaction(SIGALRM, &Old, nullptr);
394 : }
395 :
396 : // Return the proper exit status. Detect error conditions
397 : // so we can return -1 for them and set ErrMsg informatively.
398 : int result = 0;
399 19302 : if (WIFEXITED(status)) {
400 19216 : result = WEXITSTATUS(status);
401 19216 : WaitResult.ReturnCode = result;
402 :
403 19216 : if (result == 127) {
404 0 : if (ErrMsg)
405 0 : *ErrMsg = llvm::sys::StrError(ENOENT);
406 0 : WaitResult.ReturnCode = -1;
407 0 : return WaitResult;
408 : }
409 19216 : if (result == 126) {
410 0 : if (ErrMsg)
411 : *ErrMsg = "Program could not be executed";
412 0 : WaitResult.ReturnCode = -1;
413 0 : return WaitResult;
414 : }
415 86 : } else if (WIFSIGNALED(status)) {
416 86 : if (ErrMsg) {
417 86 : *ErrMsg = strsignal(WTERMSIG(status));
418 : #ifdef WCOREDUMP
419 86 : if (WCOREDUMP(status))
420 : *ErrMsg += " (core dumped)";
421 : #endif
422 : }
423 : // Return a special value to indicate that the process received an unhandled
424 : // signal during execution as opposed to failing to execute.
425 86 : WaitResult.ReturnCode = -2;
426 : }
427 19302 : return WaitResult;
428 : }
429 :
430 95825 : std::error_code sys::ChangeStdinToBinary() {
431 : // Do nothing, as Unix doesn't differentiate between text and binary.
432 95825 : return std::error_code();
433 : }
434 :
435 29825 : std::error_code sys::ChangeStdoutToBinary() {
436 : // Do nothing, as Unix doesn't differentiate between text and binary.
437 29825 : return std::error_code();
438 : }
439 :
440 : std::error_code
441 2 : llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
442 : WindowsEncodingMethod Encoding /*unused*/) {
443 : std::error_code EC;
444 4 : llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::OpenFlags::F_Text);
445 :
446 2 : if (EC)
447 0 : return EC;
448 :
449 2 : OS << Contents;
450 :
451 2 : if (OS.has_error())
452 : return make_error_code(errc::io_error);
453 :
454 2 : return EC;
455 : }
456 :
457 13562 : bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
458 : ArrayRef<StringRef> Args) {
459 13562 : static long ArgMax = sysconf(_SC_ARG_MAX);
460 : // POSIX requires that _POSIX_ARG_MAX is 4096, which is the lowest possible
461 : // value for ARG_MAX on a POSIX compliant system.
462 : static long ArgMin = _POSIX_ARG_MAX;
463 :
464 : // This the same baseline used by xargs.
465 : long EffectiveArgMax = 128 * 1024;
466 :
467 13562 : if (EffectiveArgMax > ArgMax)
468 : EffectiveArgMax = ArgMax;
469 13562 : else if (EffectiveArgMax < ArgMin)
470 : EffectiveArgMax = ArgMin;
471 :
472 : // System says no practical limit.
473 13562 : if (ArgMax == -1)
474 : return true;
475 :
476 : // Conservatively account for space required by environment variables.
477 13562 : long HalfArgMax = EffectiveArgMax / 2;
478 :
479 13562 : size_t ArgLength = Program.size() + 1;
480 962812 : for (StringRef Arg : Args) {
481 : // Ensure that we do not exceed the MAX_ARG_STRLEN constant on Linux, which
482 : // does not have a constant unlike what the man pages would have you
483 : // believe. Since this limit is pretty high, perform the check
484 : // unconditionally rather than trying to be aggressive and limiting it to
485 : // Linux only.
486 949252 : if (Arg.size() >= (32 * 4096))
487 : return false;
488 :
489 949251 : ArgLength += Arg.size() + 1;
490 949251 : if (ArgLength > size_t(HalfArgMax)) {
491 : return false;
492 : }
493 : }
494 :
495 13560 : return true;
496 : }
497 : }
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