LLVM 19.0.0git
Program.inc
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1//===- llvm/Support/Unix/Program.inc ----------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Unix specific portion of the Program class.
10//
11//===----------------------------------------------------------------------===//
12
13//===----------------------------------------------------------------------===//
14//=== WARNING: Implementation here must contain only generic UNIX
15//=== code that is guaranteed to work on *all* UNIX variants.
16//===----------------------------------------------------------------------===//
17
19
20#include "Unix.h"
22#include "llvm/Config/config.h"
25#include "llvm/Support/Errc.h"
27#include "llvm/Support/Path.h"
31#if HAVE_SYS_STAT_H
32#include <sys/stat.h>
33#endif
34#if HAVE_SYS_RESOURCE_H
35#include <sys/resource.h>
36#endif
37#if HAVE_SIGNAL_H
38#include <signal.h>
39#endif
40#if HAVE_FCNTL_H
41#include <fcntl.h>
42#endif
43#if HAVE_UNISTD_H
44#include <unistd.h>
45#endif
46#ifdef HAVE_POSIX_SPAWN
47#include <spawn.h>
48
49#if defined(__APPLE__)
50#include <TargetConditionals.h>
51#endif
52
53#if defined(__APPLE__) && !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE)
54#define USE_NSGETENVIRON 1
55#else
56#define USE_NSGETENVIRON 0
57#endif
58
59#if !USE_NSGETENVIRON
60extern char **environ;
61#else
62#include <crt_externs.h> // _NSGetEnviron
63#endif
64#endif
65
66using namespace llvm;
67using namespace sys;
68
69ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
70
71ErrorOr<std::string> sys::findProgramByName(StringRef Name,
72 ArrayRef<StringRef> Paths) {
73 assert(!Name.empty() && "Must have a name!");
74 // Use the given path verbatim if it contains any slashes; this matches
75 // the behavior of sh(1) and friends.
76 if (Name.contains('/'))
77 return std::string(Name);
78
79 SmallVector<StringRef, 16> EnvironmentPaths;
80 if (Paths.empty())
81 if (const char *PathEnv = std::getenv("PATH")) {
82 SplitString(PathEnv, EnvironmentPaths, ":");
83 Paths = EnvironmentPaths;
84 }
85
86 for (auto Path : Paths) {
87 if (Path.empty())
88 continue;
89
90 // Check to see if this first directory contains the executable...
91 SmallString<128> FilePath(Path);
92 sys::path::append(FilePath, Name);
93 if (sys::fs::can_execute(FilePath.c_str()))
94 return std::string(FilePath); // Found the executable!
95 }
96 return errc::no_such_file_or_directory;
97}
98
99static bool RedirectIO(std::optional<StringRef> Path, int FD, std::string *ErrMsg) {
100 if (!Path) // Noop
101 return false;
102 std::string File;
103 if (Path->empty())
104 // Redirect empty paths to /dev/null
105 File = "/dev/null";
106 else
107 File = std::string(*Path);
108
109 // Open the file
110 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666);
111 if (InFD == -1) {
112 MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for " +
113 (FD == 0 ? "input" : "output"));
114 return true;
115 }
116
117 // Install it as the requested FD
118 if (dup2(InFD, FD) == -1) {
119 MakeErrMsg(ErrMsg, "Cannot dup2");
120 close(InFD);
121 return true;
122 }
123 close(InFD); // Close the original FD
124 return false;
125}
126
127#ifdef HAVE_POSIX_SPAWN
128static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
129 posix_spawn_file_actions_t *FileActions) {
130 if (!Path) // Noop
131 return false;
132 const char *File;
133 if (Path->empty())
134 // Redirect empty paths to /dev/null
135 File = "/dev/null";
136 else
137 File = Path->c_str();
138
139 if (int Err = posix_spawn_file_actions_addopen(
140 FileActions, FD, File, FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
141 return MakeErrMsg(ErrMsg, "Cannot posix_spawn_file_actions_addopen", Err);
142 return false;
143}
144#endif
145
146static void TimeOutHandler(int Sig) {}
147
148static void SetMemoryLimits(unsigned size) {
149#if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
150 struct rlimit r;
151 __typeof__(r.rlim_cur) limit = (__typeof__(r.rlim_cur))(size)*1048576;
152
153 // Heap size
154 getrlimit(RLIMIT_DATA, &r);
155 r.rlim_cur = limit;
156 setrlimit(RLIMIT_DATA, &r);
157#ifdef RLIMIT_RSS
158 // Resident set size.
159 getrlimit(RLIMIT_RSS, &r);
160 r.rlim_cur = limit;
161 setrlimit(RLIMIT_RSS, &r);
162#endif
163#endif
164}
165
166static std::vector<const char *>
167toNullTerminatedCStringArray(ArrayRef<StringRef> Strings, StringSaver &Saver) {
168 std::vector<const char *> Result;
169 for (StringRef S : Strings)
170 Result.push_back(Saver.save(S).data());
171 Result.push_back(nullptr);
172 return Result;
173}
174
175static bool Execute(ProcessInfo &PI, StringRef Program,
176 ArrayRef<StringRef> Args, std::optional<ArrayRef<StringRef>> Env,
177 ArrayRef<std::optional<StringRef>> Redirects,
178 unsigned MemoryLimit, std::string *ErrMsg,
179 BitVector *AffinityMask) {
180 if (!llvm::sys::fs::exists(Program)) {
181 if (ErrMsg)
182 *ErrMsg = std::string("Executable \"") + Program.str() +
183 std::string("\" doesn't exist!");
184 return false;
185 }
186
187 assert(!AffinityMask && "Starting a process with an affinity mask is "
188 "currently not supported on Unix!");
189
191 StringSaver Saver(Allocator);
192 std::vector<const char *> ArgVector, EnvVector;
193 const char **Argv = nullptr;
194 const char **Envp = nullptr;
195 ArgVector = toNullTerminatedCStringArray(Args, Saver);
196 Argv = ArgVector.data();
197 if (Env) {
198 EnvVector = toNullTerminatedCStringArray(*Env, Saver);
199 Envp = EnvVector.data();
200 }
201
202 // If this OS has posix_spawn and there is no memory limit being implied, use
203 // posix_spawn. It is more efficient than fork/exec.
204#ifdef HAVE_POSIX_SPAWN
205 if (MemoryLimit == 0) {
206 posix_spawn_file_actions_t FileActionsStore;
207 posix_spawn_file_actions_t *FileActions = nullptr;
208
209 // If we call posix_spawn_file_actions_addopen we have to make sure the
210 // c strings we pass to it stay alive until the call to posix_spawn,
211 // so we copy any StringRefs into this variable.
212 std::string RedirectsStorage[3];
213
214 if (!Redirects.empty()) {
215 assert(Redirects.size() == 3);
216 std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
217 for (int I = 0; I < 3; ++I) {
218 if (Redirects[I]) {
219 RedirectsStorage[I] = std::string(*Redirects[I]);
220 RedirectsStr[I] = &RedirectsStorage[I];
221 }
222 }
223
224 FileActions = &FileActionsStore;
225 posix_spawn_file_actions_init(FileActions);
226
227 // Redirect stdin/stdout.
228 if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
229 RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
230 return false;
231 if (!Redirects[1] || !Redirects[2] || *Redirects[1] != *Redirects[2]) {
232 // Just redirect stderr
233 if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
234 return false;
235 } else {
236 // If stdout and stderr should go to the same place, redirect stderr
237 // to the FD already open for stdout.
238 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
239 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
240 }
241 }
242
243 if (!Envp)
244#if !USE_NSGETENVIRON
245 Envp = const_cast<const char **>(environ);
246#else
247 // environ is missing in dylibs.
248 Envp = const_cast<const char **>(*_NSGetEnviron());
249#endif
250
251 constexpr int maxRetries = 8;
252 int retries = 0;
253 pid_t PID;
254 int Err;
255 do {
256 PID = 0; // Make Valgrind happy.
257 Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
258 /*attrp*/ nullptr, const_cast<char **>(Argv),
259 const_cast<char **>(Envp));
260 } while (Err == EINTR && ++retries < maxRetries);
261
262 if (FileActions)
263 posix_spawn_file_actions_destroy(FileActions);
264
265 if (Err)
266 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
267
268 PI.Pid = PID;
269 PI.Process = PID;
270
271 return true;
272 }
273#endif
274
275 // Create a child process.
276 int child = fork();
277 switch (child) {
278 // An error occurred: Return to the caller.
279 case -1:
280 MakeErrMsg(ErrMsg, "Couldn't fork");
281 return false;
282
283 // Child process: Execute the program.
284 case 0: {
285 // Redirect file descriptors...
286 if (!Redirects.empty()) {
287 // Redirect stdin
288 if (RedirectIO(Redirects[0], 0, ErrMsg)) {
289 return false;
290 }
291 // Redirect stdout
292 if (RedirectIO(Redirects[1], 1, ErrMsg)) {
293 return false;
294 }
295 if (Redirects[1] && Redirects[2] && *Redirects[1] == *Redirects[2]) {
296 // If stdout and stderr should go to the same place, redirect stderr
297 // to the FD already open for stdout.
298 if (-1 == dup2(1, 2)) {
299 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
300 return false;
301 }
302 } else {
303 // Just redirect stderr
304 if (RedirectIO(Redirects[2], 2, ErrMsg)) {
305 return false;
306 }
307 }
308 }
309
310 // Set memory limits
311 if (MemoryLimit != 0) {
312 SetMemoryLimits(MemoryLimit);
313 }
314
315 // Execute!
316 std::string PathStr = std::string(Program);
317 if (Envp != nullptr)
318 execve(PathStr.c_str(), const_cast<char **>(Argv),
319 const_cast<char **>(Envp));
320 else
321 execv(PathStr.c_str(), const_cast<char **>(Argv));
322 // If the execve() failed, we should exit. Follow Unix protocol and
323 // return 127 if the executable was not found, and 126 otherwise.
324 // Use _exit rather than exit so that atexit functions and static
325 // object destructors cloned from the parent process aren't
326 // redundantly run, and so that any data buffered in stdio buffers
327 // cloned from the parent aren't redundantly written out.
328 _exit(errno == ENOENT ? 127 : 126);
329 }
330
331 // Parent process: Break out of the switch to do our processing.
332 default:
333 break;
334 }
335
336 PI.Pid = child;
337 PI.Process = child;
338
339 return true;
340}
341
342namespace llvm {
343namespace sys {
344
345#if defined(_AIX)
346static pid_t(wait4)(pid_t pid, int *status, int options, struct rusage *usage);
347#elif !defined(__Fuchsia__)
348using ::wait4;
349#endif
350
351} // namespace sys
352} // namespace llvm
353
354#ifdef _AIX
355#ifndef _ALL_SOURCE
356extern "C" pid_t(wait4)(pid_t pid, int *status, int options,
357 struct rusage *usage);
358#endif
359pid_t(llvm::sys::wait4)(pid_t pid, int *status, int options,
360 struct rusage *usage) {
361 assert(pid > 0 && "Only expecting to handle actual PID values!");
362 assert((options & ~WNOHANG) == 0 && "Expecting WNOHANG at most!");
363 assert(usage && "Expecting usage collection!");
364
365 // AIX wait4 does not work well with WNOHANG.
366 if (!(options & WNOHANG))
367 return ::wait4(pid, status, options, usage);
368
369 // For WNOHANG, we use waitid (which supports WNOWAIT) until the child process
370 // has terminated.
371 siginfo_t WaitIdInfo;
372 WaitIdInfo.si_pid = 0;
373 int WaitIdRetVal =
374 waitid(P_PID, pid, &WaitIdInfo, WNOWAIT | WEXITED | options);
375
376 if (WaitIdRetVal == -1 || WaitIdInfo.si_pid == 0)
377 return WaitIdRetVal;
378
379 assert(WaitIdInfo.si_pid == pid);
380
381 // The child has already terminated, so a blocking wait on it is okay in the
382 // absence of indiscriminate `wait` calls from the current process (which
383 // would cause the call here to fail with ECHILD).
384 return ::wait4(pid, status, options & ~WNOHANG, usage);
385}
386#endif
387
389 std::optional<unsigned> SecondsToWait,
390 std::string *ErrMsg,
391 std::optional<ProcessStatistics> *ProcStat,
392 bool Polling) {
393 struct sigaction Act, Old;
394 assert(PI.Pid && "invalid pid to wait on, process not started?");
395
396 int WaitPidOptions = 0;
397 pid_t ChildPid = PI.Pid;
398 bool WaitUntilTerminates = false;
399 if (!SecondsToWait) {
400 WaitUntilTerminates = true;
401 } else {
402 if (*SecondsToWait == 0)
403 WaitPidOptions = WNOHANG;
404
405 // Install a timeout handler. The handler itself does nothing, but the
406 // simple fact of having a handler at all causes the wait below to return
407 // with EINTR, unlike if we used SIG_IGN.
408 memset(&Act, 0, sizeof(Act));
409 Act.sa_handler = TimeOutHandler;
410 sigemptyset(&Act.sa_mask);
411 sigaction(SIGALRM, &Act, &Old);
412 // FIXME The alarm signal may be delivered to another thread.
413 alarm(*SecondsToWait);
414 }
415
416 // Parent process: Wait for the child process to terminate.
417 int status = 0;
418 ProcessInfo WaitResult;
419#ifndef __Fuchsia__
420 rusage Info;
421 if (ProcStat)
422 ProcStat->reset();
423
424 do {
425 WaitResult.Pid = sys::wait4(ChildPid, &status, WaitPidOptions, &Info);
426 } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
427#endif
428
429 if (WaitResult.Pid != PI.Pid) {
430 if (WaitResult.Pid == 0) {
431 // Non-blocking wait.
432 return WaitResult;
433 } else {
434 if (SecondsToWait && errno == EINTR && !Polling) {
435 // Kill the child.
436 kill(PI.Pid, SIGKILL);
437
438 // Turn off the alarm and restore the signal handler
439 alarm(0);
440 sigaction(SIGALRM, &Old, nullptr);
441
442 // Wait for child to die
443 // FIXME This could grab some other child process out from another
444 // waiting thread and then leave a zombie anyway.
445 if (wait(&status) != ChildPid)
446 MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
447 else
448 MakeErrMsg(ErrMsg, "Child timed out", 0);
449
450 WaitResult.ReturnCode = -2; // Timeout detected
451 return WaitResult;
452 } else if (errno != EINTR) {
453 MakeErrMsg(ErrMsg, "Error waiting for child process");
454 WaitResult.ReturnCode = -1;
455 return WaitResult;
456 }
457 }
458 }
459
460 // We exited normally without timeout, so turn off the timer.
461 if (SecondsToWait && !WaitUntilTerminates) {
462 alarm(0);
463 sigaction(SIGALRM, &Old, nullptr);
464 }
465
466#ifndef __Fuchsia__
467 if (ProcStat) {
468 std::chrono::microseconds UserT = toDuration(Info.ru_utime);
469 std::chrono::microseconds KernelT = toDuration(Info.ru_stime);
470 uint64_t PeakMemory = 0;
471#if !defined(__HAIKU__) && !defined(__MVS__)
472 PeakMemory = static_cast<uint64_t>(Info.ru_maxrss);
473#endif
474 *ProcStat = ProcessStatistics{UserT + KernelT, UserT, PeakMemory};
475 }
476#endif
477
478 // Return the proper exit status. Detect error conditions
479 // so we can return -1 for them and set ErrMsg informatively.
480 int result = 0;
481 if (WIFEXITED(status)) {
482 result = WEXITSTATUS(status);
483 WaitResult.ReturnCode = result;
484
485 if (result == 127) {
486 if (ErrMsg)
487 *ErrMsg = llvm::sys::StrError(ENOENT);
488 WaitResult.ReturnCode = -1;
489 return WaitResult;
490 }
491 if (result == 126) {
492 if (ErrMsg)
493 *ErrMsg = "Program could not be executed";
494 WaitResult.ReturnCode = -1;
495 return WaitResult;
496 }
497 } else if (WIFSIGNALED(status)) {
498 if (ErrMsg) {
499 *ErrMsg = strsignal(WTERMSIG(status));
500#ifdef WCOREDUMP
501 if (WCOREDUMP(status))
502 *ErrMsg += " (core dumped)";
503#endif
504 }
505 // Return a special value to indicate that the process received an unhandled
506 // signal during execution as opposed to failing to execute.
507 WaitResult.ReturnCode = -2;
508 }
509 return WaitResult;
510}
511
512std::error_code llvm::sys::ChangeStdinMode(fs::OpenFlags Flags) {
513 if (!(Flags & fs::OF_Text))
514 return ChangeStdinToBinary();
515 return std::error_code();
516}
517
518std::error_code llvm::sys::ChangeStdoutMode(fs::OpenFlags Flags) {
519 if (!(Flags & fs::OF_Text))
520 return ChangeStdoutToBinary();
521 return std::error_code();
522}
523
524std::error_code llvm::sys::ChangeStdinToBinary() {
525#ifdef __MVS__
526 return disableAutoConversion(STDIN_FILENO);
527#else
528 // Do nothing, as Unix doesn't differentiate between text and binary.
529 return std::error_code();
530#endif
531}
532
533std::error_code llvm::sys::ChangeStdoutToBinary() {
534 // Do nothing, as Unix doesn't differentiate between text and binary.
535 return std::error_code();
536}
537
538std::error_code
540 WindowsEncodingMethod Encoding /*unused*/) {
541 std::error_code EC;
542 llvm::raw_fd_ostream OS(FileName, EC,
544
545 if (EC)
546 return EC;
547
548 OS << Contents;
549
550 if (OS.has_error())
551 return make_error_code(errc::io_error);
552
553 return EC;
554}
555
557 ArrayRef<StringRef> Args) {
558 static long ArgMax = sysconf(_SC_ARG_MAX);
559 // POSIX requires that _POSIX_ARG_MAX is 4096, which is the lowest possible
560 // value for ARG_MAX on a POSIX compliant system.
561 static long ArgMin = _POSIX_ARG_MAX;
562
563 // This the same baseline used by xargs.
564 long EffectiveArgMax = 128 * 1024;
565
566 if (EffectiveArgMax > ArgMax)
567 EffectiveArgMax = ArgMax;
568 else if (EffectiveArgMax < ArgMin)
569 EffectiveArgMax = ArgMin;
570
571 // System says no practical limit.
572 if (ArgMax == -1)
573 return true;
574
575 // Conservatively account for space required by environment variables.
576 long HalfArgMax = EffectiveArgMax / 2;
577
578 size_t ArgLength = Program.size() + 1;
579 for (StringRef Arg : Args) {
580 // Ensure that we do not exceed the MAX_ARG_STRLEN constant on Linux, which
581 // does not have a constant unlike what the man pages would have you
582 // believe. Since this limit is pretty high, perform the check
583 // unconditionally rather than trying to be aggressive and limiting it to
584 // Linux only.
585 if (Arg.size() >= (32 * 4096))
586 return false;
587
588 ArgLength += Arg.size() + 1;
589 if (ArgLength > size_t(HalfArgMax)) {
590 return false;
591 }
592 }
593
594 return true;
595}
Analysis containing CSE Info
Definition: CSEInfo.cpp:27
std::string Name
#define I(x, y, z)
Definition: MD5.cpp:58
static bool Execute(ProcessInfo &PI, StringRef Program, ArrayRef< StringRef > Args, std::optional< ArrayRef< StringRef > > Env, ArrayRef< std::optional< StringRef > > Redirects, unsigned MemoryLimit, std::string *ErrMsg, BitVector *AffinityMask)
Basic Register Allocator
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
raw_pwrite_stream & OS
This file contains some functions that are useful when dealing with strings.
static bool MakeErrMsg(std::string *ErrMsg, const std::string &prefix, int errnum=-1)
This function builds an error message into ErrMsg using the prefix string and the Unix error number g...
Definition: Unix.h:59
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:160
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:66
Represents either an error or a value T.
Definition: ErrorOr.h:56
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:26
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1209
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
std::string str() const
str - Get the contents as an std::string.
Definition: StringRef.h:222
constexpr size_t size() const
size - Get the string size.
Definition: StringRef.h:137
constexpr const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:131
Saves strings in the provided stable storage and returns a StringRef with a stable character pointer.
Definition: StringSaver.h:21
StringRef save(const char *S)
Definition: StringSaver.h:30
A raw_ostream that writes to a file descriptor.
Definition: raw_ostream.h:470
std::vector< std::string > ArgVector
LVOptions & options()
Definition: LVOptions.h:445
std::error_code status(const Twine &path, file_status &result, bool follow=true)
Get file status as if by POSIX stat().
bool exists(const basic_file_status &status)
Does file exist?
Definition: Path.cpp:1079
@ OF_TextWithCRLF
The file should be opened in text mode and use a carriage linefeed '\r '.
Definition: FileSystem.h:768
std::chrono::nanoseconds toDuration(FILETIME Time)
std::string StrError()
Returns a string representation of the errno value, using whatever thread-safe variant of strerror() ...
std::error_code ChangeStdinMode(fs::OpenFlags Flags)
std::error_code ChangeStdinToBinary()
ProcessInfo Wait(const ProcessInfo &PI, std::optional< unsigned > SecondsToWait, std::string *ErrMsg=nullptr, std::optional< ProcessStatistics > *ProcStat=nullptr, bool Polling=false)
This function waits for the process specified by PI to finish.
bool commandLineFitsWithinSystemLimits(StringRef Program, ArrayRef< StringRef > Args)
Return true if the given arguments fit within system-specific argument length limits.
std::error_code ChangeStdoutMode(fs::OpenFlags Flags)
WindowsEncodingMethod
File encoding options when writing contents that a non-UTF8 tool will read (on Windows systems).
Definition: Program.h:169
std::error_code ChangeStdoutToBinary()
std::error_code writeFileWithEncoding(StringRef FileName, StringRef Contents, WindowsEncodingMethod Encoding=WEM_UTF8)
Saves the UTF8-encoded contents string into the file FileName using a specific encoding.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
std::error_code make_error_code(BitcodeError E)
This struct encapsulates information about a process.
Definition: Program.h:46
process_t Process
The process identifier.
Definition: Program.h:50
int ReturnCode
Platform-dependent process object.
Definition: Program.h:53
This struct encapsulates information about a process execution.
Definition: Program.h:59