LLVM 19.0.0git
Process.inc
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1//===- Unix/Process.cpp - Unix Process Implementation --------- -*- 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 provides the generic Unix implementation of the Process class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "Unix.h"
14#include "llvm/ADT/Hashing.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/Config/config.h"
17#include <mutex>
18#include <optional>
19#if HAVE_FCNTL_H
20#include <fcntl.h>
21#endif
22#ifdef HAVE_SYS_TIME_H
23#include <sys/time.h>
24#endif
25#ifdef HAVE_SYS_RESOURCE_H
26#include <sys/resource.h>
27#endif
28#ifdef HAVE_SYS_STAT_H
29#include <sys/stat.h>
30#endif
31#if HAVE_SIGNAL_H
32#include <signal.h>
33#endif
34#if defined(HAVE_MALLINFO) || defined(HAVE_MALLINFO2)
35#include <malloc.h>
36#endif
37#if defined(HAVE_MALLCTL)
38#include <malloc_np.h>
39#endif
40#ifdef HAVE_MALLOC_MALLOC_H
41#include <malloc/malloc.h>
42#endif
43#ifdef HAVE_SYS_IOCTL_H
44#include <sys/ioctl.h>
45#endif
46#ifdef HAVE_TERMIOS_H
47#include <termios.h>
48#endif
49
50//===----------------------------------------------------------------------===//
51//=== WARNING: Implementation here must contain only generic UNIX code that
52//=== is guaranteed to work on *all* UNIX variants.
53//===----------------------------------------------------------------------===//
54
55using namespace llvm;
56using namespace sys;
57
58static std::pair<std::chrono::microseconds, std::chrono::microseconds>
59getRUsageTimes() {
60#if defined(HAVE_GETRUSAGE)
61 struct rusage RU;
62 ::getrusage(RUSAGE_SELF, &RU);
63 return {toDuration(RU.ru_utime), toDuration(RU.ru_stime)};
64#else
65#ifndef __MVS__ // Exclude for MVS in case -pedantic is used
66#warning Cannot get usage times on this platform
67#endif
68 return {std::chrono::microseconds::zero(), std::chrono::microseconds::zero()};
69#endif
70}
71
72Process::Pid Process::getProcessId() {
73 static_assert(sizeof(Pid) >= sizeof(pid_t),
74 "Process::Pid should be big enough to store pid_t");
75 return Pid(::getpid());
76}
77
78// On Cygwin, getpagesize() returns 64k(AllocationGranularity) and
79// offset in mmap(3) should be aligned to the AllocationGranularity.
80Expected<unsigned> Process::getPageSize() {
81#if defined(HAVE_GETPAGESIZE)
82 static const int page_size = ::getpagesize();
83#elif defined(HAVE_SYSCONF)
84 static long page_size = ::sysconf(_SC_PAGE_SIZE);
85#else
86#error Cannot get the page size on this machine
87#endif
88 if (page_size == -1)
89 return errorCodeToError(std::error_code(errno, std::generic_category()));
90
91 return static_cast<unsigned>(page_size);
92}
93
94size_t Process::GetMallocUsage() {
95#if defined(HAVE_MALLINFO2)
96 struct mallinfo2 mi;
97 mi = ::mallinfo2();
98 return mi.uordblks;
99#elif defined(HAVE_MALLINFO)
100 struct mallinfo mi;
101 mi = ::mallinfo();
102 return mi.uordblks;
103#elif defined(HAVE_MALLOC_ZONE_STATISTICS) && defined(HAVE_MALLOC_MALLOC_H)
104 malloc_statistics_t Stats;
105 malloc_zone_statistics(malloc_default_zone(), &Stats);
106 return Stats.size_in_use; // darwin
107#elif defined(HAVE_MALLCTL)
108 size_t alloc, sz;
109 sz = sizeof(size_t);
110 if (mallctl("stats.allocated", &alloc, &sz, NULL, 0) == 0)
111 return alloc;
112 return 0;
113#elif defined(HAVE_SBRK)
114 // Note this is only an approximation and more closely resembles
115 // the value returned by mallinfo in the arena field.
116 static char *StartOfMemory = reinterpret_cast<char *>(::sbrk(0));
117 char *EndOfMemory = (char *)sbrk(0);
118 if (EndOfMemory != ((char *)-1) && StartOfMemory != ((char *)-1))
119 return EndOfMemory - StartOfMemory;
120 return 0;
121#else
122#ifndef __MVS__ // Exclude for MVS in case -pedantic is used
123#warning Cannot get malloc info on this platform
124#endif
125 return 0;
126#endif
127}
128
129void Process::GetTimeUsage(TimePoint<> &elapsed,
130 std::chrono::nanoseconds &user_time,
131 std::chrono::nanoseconds &sys_time) {
132 elapsed = std::chrono::system_clock::now();
133 std::tie(user_time, sys_time) = getRUsageTimes();
134}
135
136#if defined(HAVE_MACH_MACH_H) && !defined(__GNU__)
137#include <mach/mach.h>
138#endif
139
140// Some LLVM programs such as bugpoint produce core files as a normal part of
141// their operation. To prevent the disk from filling up, this function
142// does what's necessary to prevent their generation.
143void Process::PreventCoreFiles() {
144#if HAVE_SETRLIMIT
145 struct rlimit rlim;
146 rlim.rlim_cur = rlim.rlim_max = 0;
147 setrlimit(RLIMIT_CORE, &rlim);
148#endif
149
150#if defined(HAVE_MACH_MACH_H) && !defined(__GNU__)
151 // Disable crash reporting on Mac OS X 10.0-10.4
152
153 // get information about the original set of exception ports for the task
154 mach_msg_type_number_t Count = 0;
155 exception_mask_t OriginalMasks[EXC_TYPES_COUNT];
156 exception_port_t OriginalPorts[EXC_TYPES_COUNT];
157 exception_behavior_t OriginalBehaviors[EXC_TYPES_COUNT];
158 thread_state_flavor_t OriginalFlavors[EXC_TYPES_COUNT];
159 kern_return_t err = task_get_exception_ports(
160 mach_task_self(), EXC_MASK_ALL, OriginalMasks, &Count, OriginalPorts,
161 OriginalBehaviors, OriginalFlavors);
162 if (err == KERN_SUCCESS) {
163 // replace each with MACH_PORT_NULL.
164 for (unsigned i = 0; i != Count; ++i)
165 task_set_exception_ports(mach_task_self(), OriginalMasks[i],
166 MACH_PORT_NULL, OriginalBehaviors[i],
167 OriginalFlavors[i]);
168 }
169
170 // Disable crash reporting on Mac OS X 10.5
171 signal(SIGABRT, _exit);
172 signal(SIGILL, _exit);
173 signal(SIGFPE, _exit);
174 signal(SIGSEGV, _exit);
175 signal(SIGBUS, _exit);
176#endif
177
178 coreFilesPrevented = true;
179}
180
181std::optional<std::string> Process::GetEnv(StringRef Name) {
182 std::string NameStr = Name.str();
183 const char *Val = ::getenv(NameStr.c_str());
184 if (!Val)
185 return std::nullopt;
186 return std::string(Val);
187}
188
189namespace {
190class FDCloser {
191public:
192 FDCloser(int &FD) : FD(FD), KeepOpen(false) {}
193 void keepOpen() { KeepOpen = true; }
194 ~FDCloser() {
195 if (!KeepOpen && FD >= 0)
196 ::close(FD);
197 }
198
199private:
200 FDCloser(const FDCloser &) = delete;
201 void operator=(const FDCloser &) = delete;
202
203 int &FD;
204 bool KeepOpen;
205};
206} // namespace
207
208std::error_code Process::FixupStandardFileDescriptors() {
209 int NullFD = -1;
210 FDCloser FDC(NullFD);
211 const int StandardFDs[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO};
212 for (int StandardFD : StandardFDs) {
213 struct stat st;
214 errno = 0;
215 if (RetryAfterSignal(-1, ::fstat, StandardFD, &st) < 0) {
216 assert(errno && "expected errno to be set if fstat failed!");
217 // fstat should return EBADF if the file descriptor is closed.
218 if (errno != EBADF)
219 return std::error_code(errno, std::generic_category());
220 }
221 // if fstat succeeds, move on to the next FD.
222 if (!errno)
223 continue;
224 assert(errno == EBADF && "expected errno to have EBADF at this point!");
225
226 if (NullFD < 0) {
227 // Call ::open in a lambda to avoid overload resolution in
228 // RetryAfterSignal when open is overloaded, such as in Bionic.
229 auto Open = [&]() { return ::open("/dev/null", O_RDWR); };
230 if ((NullFD = RetryAfterSignal(-1, Open)) < 0)
231 return std::error_code(errno, std::generic_category());
232 }
233
234 if (NullFD == StandardFD)
235 FDC.keepOpen();
236 else if (dup2(NullFD, StandardFD) < 0)
237 return std::error_code(errno, std::generic_category());
238 }
239 return std::error_code();
240}
241
242std::error_code Process::SafelyCloseFileDescriptor(int FD) {
243 // Create a signal set filled with *all* signals.
244 sigset_t FullSet, SavedSet;
245 if (sigfillset(&FullSet) < 0 || sigfillset(&SavedSet) < 0)
246 return std::error_code(errno, std::generic_category());
247
248 // Atomically swap our current signal mask with a full mask.
249#if LLVM_ENABLE_THREADS
250 if (int EC = pthread_sigmask(SIG_SETMASK, &FullSet, &SavedSet))
251 return std::error_code(EC, std::generic_category());
252#else
253 if (sigprocmask(SIG_SETMASK, &FullSet, &SavedSet) < 0)
254 return std::error_code(errno, std::generic_category());
255#endif
256 // Attempt to close the file descriptor.
257 // We need to save the error, if one occurs, because our subsequent call to
258 // pthread_sigmask might tamper with errno.
259 int ErrnoFromClose = 0;
260 if (::close(FD) < 0)
261 ErrnoFromClose = errno;
262 // Restore the signal mask back to what we saved earlier.
263 int EC = 0;
264#if LLVM_ENABLE_THREADS
265 EC = pthread_sigmask(SIG_SETMASK, &SavedSet, nullptr);
266#else
267 if (sigprocmask(SIG_SETMASK, &SavedSet, nullptr) < 0)
268 EC = errno;
269#endif
270 // The error code from close takes precedence over the one from
271 // pthread_sigmask.
272 if (ErrnoFromClose)
273 return std::error_code(ErrnoFromClose, std::generic_category());
274 return std::error_code(EC, std::generic_category());
275}
276
277bool Process::StandardInIsUserInput() {
278 return FileDescriptorIsDisplayed(STDIN_FILENO);
279}
280
281bool Process::StandardOutIsDisplayed() {
282 return FileDescriptorIsDisplayed(STDOUT_FILENO);
283}
284
285bool Process::StandardErrIsDisplayed() {
286 return FileDescriptorIsDisplayed(STDERR_FILENO);
287}
288
289bool Process::FileDescriptorIsDisplayed(int fd) {
290#if HAVE_ISATTY
291 return isatty(fd);
292#else
293 // If we don't have isatty, just return false.
294 return false;
295#endif
296}
297
298static unsigned getColumns() {
299 // If COLUMNS is defined in the environment, wrap to that many columns.
300 if (const char *ColumnsStr = std::getenv("COLUMNS")) {
301 int Columns = std::atoi(ColumnsStr);
302 if (Columns > 0)
303 return Columns;
304 }
305
306 // We used to call ioctl TIOCGWINSZ to determine the width. It is considered
307 // unuseful.
308 return 0;
309}
310
311unsigned Process::StandardOutColumns() {
312 if (!StandardOutIsDisplayed())
313 return 0;
314
315 return getColumns();
316}
317
318unsigned Process::StandardErrColumns() {
319 if (!StandardErrIsDisplayed())
320 return 0;
321
322 return getColumns();
323}
324
325#ifdef LLVM_ENABLE_TERMINFO
326// We manually declare these extern functions because finding the correct
327// headers from various terminfo, curses, or other sources is harder than
328// writing their specs down.
329extern "C" int setupterm(char *term, int filedes, int *errret);
330extern "C" struct term *set_curterm(struct term *termp);
331extern "C" int del_curterm(struct term *termp);
332extern "C" int tigetnum(char *capname);
333#endif
334
335bool checkTerminalEnvironmentForColors() {
336 if (const char *TermStr = std::getenv("TERM")) {
337 return StringSwitch<bool>(TermStr)
338 .Case("ansi", true)
339 .Case("cygwin", true)
340 .Case("linux", true)
341 .StartsWith("screen", true)
342 .StartsWith("xterm", true)
343 .StartsWith("vt100", true)
344 .StartsWith("rxvt", true)
345 .EndsWith("color", true)
346 .Default(false);
347 }
348
349 return false;
350}
351
352static bool terminalHasColors(int fd) {
353#ifdef LLVM_ENABLE_TERMINFO
354 // First, acquire a global lock because these C routines are thread hostile.
355 static std::mutex TermColorMutex;
356 std::lock_guard<std::mutex> G(TermColorMutex);
357
358 struct term *previous_term = set_curterm(nullptr);
359 int errret = 0;
360 if (setupterm(nullptr, fd, &errret) != 0)
361 // Regardless of why, if we can't get terminfo, we shouldn't try to print
362 // colors.
363 return false;
364
365 // Test whether the terminal as set up supports color output. How to do this
366 // isn't entirely obvious. We can use the curses routine 'has_colors' but it
367 // would be nice to avoid a dependency on curses proper when we can make do
368 // with a minimal terminfo parsing library. Also, we don't really care whether
369 // the terminal supports the curses-specific color changing routines, merely
370 // if it will interpret ANSI color escape codes in a reasonable way. Thus, the
371 // strategy here is just to query the baseline colors capability and if it
372 // supports colors at all to assume it will translate the escape codes into
373 // whatever range of colors it does support. We can add more detailed tests
374 // here if users report them as necessary.
375 //
376 // The 'tigetnum' routine returns -2 or -1 on errors, and might return 0 if
377 // the terminfo says that no colors are supported.
378 int colors_ti = tigetnum(const_cast<char *>("colors"));
379 bool HasColors =
380 colors_ti >= 0 ? colors_ti : checkTerminalEnvironmentForColors();
381
382 // Now extract the structure allocated by setupterm and free its memory
383 // through a really silly dance.
384 struct term *termp = set_curterm(previous_term);
385 (void)del_curterm(termp); // Drop any errors here.
386
387 // Return true if we found a color capabilities for the current terminal.
388 return HasColors;
389#else
390 // When the terminfo database is not available, check if the current terminal
391 // is one of terminals that are known to support ANSI color escape codes.
392 return checkTerminalEnvironmentForColors();
393#endif
394}
395
396bool Process::FileDescriptorHasColors(int fd) {
397 // A file descriptor has colors if it is displayed and the terminal has
398 // colors.
399 return FileDescriptorIsDisplayed(fd) && terminalHasColors(fd);
400}
401
402bool Process::StandardOutHasColors() {
403 return FileDescriptorHasColors(STDOUT_FILENO);
404}
405
406bool Process::StandardErrHasColors() {
407 return FileDescriptorHasColors(STDERR_FILENO);
408}
409
410void Process::UseANSIEscapeCodes(bool /*enable*/) {
411 // No effect.
412}
413
414bool Process::ColorNeedsFlush() {
415 // No, we use ANSI escape sequences.
416 return false;
417}
418
419const char *Process::OutputColor(char code, bool bold, bool bg) {
420 return colorcodes[bg ? 1 : 0][bold ? 1 : 0][code & 15];
421}
422
423const char *Process::OutputBold(bool bg) { return "\033[1m"; }
424
425const char *Process::OutputReverse() { return "\033[7m"; }
426
427const char *Process::ResetColor() { return "\033[0m"; }
428
429#if !HAVE_DECL_ARC4RANDOM
430static unsigned GetRandomNumberSeed() {
431 // Attempt to get the initial seed from /dev/urandom, if possible.
432 int urandomFD = open("/dev/urandom", O_RDONLY);
433
434 if (urandomFD != -1) {
435 unsigned seed;
436 // Don't use a buffered read to avoid reading more data
437 // from /dev/urandom than we need.
438 int count = read(urandomFD, (void *)&seed, sizeof(seed));
439
440 close(urandomFD);
441
442 // Return the seed if the read was successful.
443 if (count == sizeof(seed))
444 return seed;
445 }
446
447 // Otherwise, swizzle the current time and the process ID to form a reasonable
448 // seed.
449 const auto Now = std::chrono::high_resolution_clock::now();
450 return hash_combine(Now.time_since_epoch().count(), ::getpid());
451}
452#endif
453
455#if HAVE_DECL_ARC4RANDOM
456 return arc4random();
457#else
458 static int x = (static_cast<void>(::srand(GetRandomNumberSeed())), 0);
459 (void)x;
460 return ::rand();
461#endif
462}
463
464[[noreturn]] void Process::ExitNoCleanup(int RetCode) { _Exit(RetCode); }
std::string Name
#define G(x, y, z)
Definition: MD5.cpp:56
block placement Basic Block Placement Stats
static bool coreFilesPrevented
Definition: Process.cpp:107
static const char colorcodes[2][2][16][11]
Definition: Process.cpp:99
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Tagged union holding either a T or a Error.
Definition: Error.h:474
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
A switch()-like statement whose cases are string literals.
Definition: StringSwitch.h:44
StringSwitch & Case(StringLiteral S, T Value)
Definition: StringSwitch.h:69
R Default(T Value)
Definition: StringSwitch.h:182
StringSwitch & StartsWith(StringLiteral S, T Value)
Definition: StringSwitch.h:83
StringSwitch & EndsWith(StringLiteral S, T Value)
Definition: StringSwitch.h:76
static unsigned GetRandomNumber()
Get the result of a process wide random number generator.
value_type read(const void *memory, endianness endian)
Read a value of a particular endianness from memory.
Definition: Endian.h:58
decltype(auto) RetryAfterSignal(const FailT &Fail, const Fun &F, const Args &... As)
Definition: Errno.h:32
std::chrono::nanoseconds toDuration(FILETIME Time)
std::chrono::time_point< std::chrono::system_clock, D > TimePoint
A time point on the system clock.
Definition: Chrono.h:34
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
auto count(R &&Range, const E &Element)
Wrapper function around std::count to count the number of times an element Element occurs in the give...
Definition: STLExtras.h:1923
Error errorCodeToError(std::error_code EC)
Helper for converting an std::error_code to a Error.
Definition: Error.cpp:103
hash_code hash_combine(const Ts &...args)
Combine values into a single hash_code.
Definition: Hashing.h:613