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)
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 getrlimit(RLIMIT_CORE, &rlim);
147#ifdef __linux__
148 // On Linux, if the kernel.core_pattern sysctl starts with a '|' (i.e. it
149 // is being piped to a coredump handler such as systemd-coredumpd), the
150 // kernel ignores RLIMIT_CORE (since we aren't creating a file in the file
151 // system) except for the magic value of 1, which disables coredumps when
152 // piping. 1 byte is too small for any kind of valid core dump, so it
153 // also disables coredumps if kernel.core_pattern creates files directly.
154 // While most piped coredump handlers do respect the crashing processes'
155 // RLIMIT_CORE, this is notable not the case for Debian's systemd-coredump
156 // due to a local patch that changes sysctl.d/50-coredump.conf to ignore
157 // the specified limit and instead use RLIM_INFINITY.
158 //
159 // The alternative to using RLIMIT_CORE=1 would be to use prctl() with the
160 // PR_SET_DUMPABLE flag, however that also prevents ptrace(), so makes it
161 // impossible to attach a debugger.
162 rlim.rlim_cur = std::min<rlim_t>(1, rlim.rlim_max);
163#else
164 rlim.rlim_cur = 0;
165#endif
166 setrlimit(RLIMIT_CORE, &rlim);
167#endif
168
169#if defined(HAVE_MACH_MACH_H) && !defined(__GNU__)
170 // Disable crash reporting on Mac OS X 10.0-10.4
171
172 // get information about the original set of exception ports for the task
173 mach_msg_type_number_t Count = 0;
174 exception_mask_t OriginalMasks[EXC_TYPES_COUNT];
175 exception_port_t OriginalPorts[EXC_TYPES_COUNT];
176 exception_behavior_t OriginalBehaviors[EXC_TYPES_COUNT];
177 thread_state_flavor_t OriginalFlavors[EXC_TYPES_COUNT];
178 kern_return_t err = task_get_exception_ports(
179 mach_task_self(), EXC_MASK_ALL, OriginalMasks, &Count, OriginalPorts,
180 OriginalBehaviors, OriginalFlavors);
181 if (err == KERN_SUCCESS) {
182 // replace each with MACH_PORT_NULL.
183 for (unsigned i = 0; i != Count; ++i)
184 task_set_exception_ports(mach_task_self(), OriginalMasks[i],
185 MACH_PORT_NULL, OriginalBehaviors[i],
186 OriginalFlavors[i]);
187 }
188
189 // Disable crash reporting on Mac OS X 10.5
190 signal(SIGABRT, _exit);
191 signal(SIGILL, _exit);
192 signal(SIGFPE, _exit);
193 signal(SIGSEGV, _exit);
194 signal(SIGBUS, _exit);
195#endif
196
197 coreFilesPrevented = true;
198}
199
200std::optional<std::string> Process::GetEnv(StringRef Name) {
201 std::string NameStr = Name.str();
202 const char *Val = ::getenv(NameStr.c_str());
203 if (!Val)
204 return std::nullopt;
205 return std::string(Val);
206}
207
208namespace {
209class FDCloser {
210public:
211 FDCloser(int &FD) : FD(FD), KeepOpen(false) {}
212 void keepOpen() { KeepOpen = true; }
213 ~FDCloser() {
214 if (!KeepOpen && FD >= 0)
215 ::close(FD);
216 }
217
218private:
219 FDCloser(const FDCloser &) = delete;
220 void operator=(const FDCloser &) = delete;
221
222 int &FD;
223 bool KeepOpen;
224};
225} // namespace
226
227std::error_code Process::FixupStandardFileDescriptors() {
228 int NullFD = -1;
229 FDCloser FDC(NullFD);
230 const int StandardFDs[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO};
231 for (int StandardFD : StandardFDs) {
232 struct stat st;
233 errno = 0;
234 if (RetryAfterSignal(-1, ::fstat, StandardFD, &st) < 0) {
235 assert(errno && "expected errno to be set if fstat failed!");
236 // fstat should return EBADF if the file descriptor is closed.
237 if (errno != EBADF)
238 return errnoAsErrorCode();
239 }
240 // if fstat succeeds, move on to the next FD.
241 if (!errno)
242 continue;
243 assert(errno == EBADF && "expected errno to have EBADF at this point!");
244
245 if (NullFD < 0) {
246 // Call ::open in a lambda to avoid overload resolution in
247 // RetryAfterSignal when open is overloaded, such as in Bionic.
248 auto Open = [&]() { return ::open("/dev/null", O_RDWR); };
249 if ((NullFD = RetryAfterSignal(-1, Open)) < 0)
250 return errnoAsErrorCode();
251 }
252
253 if (NullFD == StandardFD)
254 FDC.keepOpen();
255 else if (dup2(NullFD, StandardFD) < 0)
256 return errnoAsErrorCode();
257 }
258 return std::error_code();
259}
260
261std::error_code Process::SafelyCloseFileDescriptor(int FD) {
262 // Create a signal set filled with *all* signals.
263 sigset_t FullSet, SavedSet;
264 if (sigfillset(&FullSet) < 0 || sigfillset(&SavedSet) < 0)
265 return errnoAsErrorCode();
266
267 // Atomically swap our current signal mask with a full mask.
268#if LLVM_ENABLE_THREADS
269 if (int EC = pthread_sigmask(SIG_SETMASK, &FullSet, &SavedSet))
270 return std::error_code(EC, std::generic_category());
271#else
272 if (sigprocmask(SIG_SETMASK, &FullSet, &SavedSet) < 0)
273 return errnoAsErrorCode();
274#endif
275 // Attempt to close the file descriptor.
276 // We need to save the error, if one occurs, because our subsequent call to
277 // pthread_sigmask might tamper with errno.
278 int ErrnoFromClose = 0;
279 if (::close(FD) < 0)
280 ErrnoFromClose = errno;
281 // Restore the signal mask back to what we saved earlier.
282 int EC = 0;
283#if LLVM_ENABLE_THREADS
284 EC = pthread_sigmask(SIG_SETMASK, &SavedSet, nullptr);
285#else
286 if (sigprocmask(SIG_SETMASK, &SavedSet, nullptr) < 0)
287 EC = errno;
288#endif
289 // The error code from close takes precedence over the one from
290 // pthread_sigmask.
291 if (ErrnoFromClose)
292 return std::error_code(ErrnoFromClose, std::generic_category());
293 return std::error_code(EC, std::generic_category());
294}
295
296bool Process::StandardInIsUserInput() {
297 return FileDescriptorIsDisplayed(STDIN_FILENO);
298}
299
300bool Process::StandardOutIsDisplayed() {
301 return FileDescriptorIsDisplayed(STDOUT_FILENO);
302}
303
304bool Process::StandardErrIsDisplayed() {
305 return FileDescriptorIsDisplayed(STDERR_FILENO);
306}
307
308bool Process::FileDescriptorIsDisplayed(int fd) {
309#if HAVE_ISATTY
310 return isatty(fd);
311#else
312 // If we don't have isatty, just return false.
313 return false;
314#endif
315}
316
317static unsigned getColumns() {
318 // If COLUMNS is defined in the environment, wrap to that many columns.
319 if (const char *ColumnsStr = std::getenv("COLUMNS")) {
320 int Columns = std::atoi(ColumnsStr);
321 if (Columns > 0)
322 return Columns;
323 }
324
325 // We used to call ioctl TIOCGWINSZ to determine the width. It is considered
326 // unuseful.
327 return 0;
328}
329
330unsigned Process::StandardOutColumns() {
331 if (!StandardOutIsDisplayed())
332 return 0;
333
334 return getColumns();
335}
336
337unsigned Process::StandardErrColumns() {
338 if (!StandardErrIsDisplayed())
339 return 0;
340
341 return getColumns();
342}
343
344#ifdef LLVM_ENABLE_TERMINFO
345// We manually declare these extern functions because finding the correct
346// headers from various terminfo, curses, or other sources is harder than
347// writing their specs down.
348extern "C" int setupterm(char *term, int filedes, int *errret);
349extern "C" struct term *set_curterm(struct term *termp);
350extern "C" int del_curterm(struct term *termp);
351extern "C" int tigetnum(char *capname);
352#endif
353
354bool checkTerminalEnvironmentForColors() {
355 if (const char *TermStr = std::getenv("TERM")) {
356 return StringSwitch<bool>(TermStr)
357 .Case("ansi", true)
358 .Case("cygwin", true)
359 .Case("linux", true)
360 .StartsWith("screen", true)
361 .StartsWith("xterm", true)
362 .StartsWith("vt100", true)
363 .StartsWith("rxvt", true)
364 .EndsWith("color", true)
365 .Default(false);
366 }
367
368 return false;
369}
370
371static bool terminalHasColors(int fd) {
372#ifdef LLVM_ENABLE_TERMINFO
373 // First, acquire a global lock because these C routines are thread hostile.
374 static std::mutex TermColorMutex;
375 std::lock_guard<std::mutex> G(TermColorMutex);
376
377 struct term *previous_term = set_curterm(nullptr);
378 int errret = 0;
379 if (setupterm(nullptr, fd, &errret) != 0)
380 // Regardless of why, if we can't get terminfo, we shouldn't try to print
381 // colors.
382 return false;
383
384 // Test whether the terminal as set up supports color output. How to do this
385 // isn't entirely obvious. We can use the curses routine 'has_colors' but it
386 // would be nice to avoid a dependency on curses proper when we can make do
387 // with a minimal terminfo parsing library. Also, we don't really care whether
388 // the terminal supports the curses-specific color changing routines, merely
389 // if it will interpret ANSI color escape codes in a reasonable way. Thus, the
390 // strategy here is just to query the baseline colors capability and if it
391 // supports colors at all to assume it will translate the escape codes into
392 // whatever range of colors it does support. We can add more detailed tests
393 // here if users report them as necessary.
394 //
395 // The 'tigetnum' routine returns -2 or -1 on errors, and might return 0 if
396 // the terminfo says that no colors are supported.
397 int colors_ti = tigetnum(const_cast<char *>("colors"));
398 bool HasColors =
399 colors_ti >= 0 ? colors_ti : checkTerminalEnvironmentForColors();
400
401 // Now extract the structure allocated by setupterm and free its memory
402 // through a really silly dance.
403 struct term *termp = set_curterm(previous_term);
404 (void)del_curterm(termp); // Drop any errors here.
405
406 // Return true if we found a color capabilities for the current terminal.
407 return HasColors;
408#else
409 // When the terminfo database is not available, check if the current terminal
410 // is one of terminals that are known to support ANSI color escape codes.
411 return checkTerminalEnvironmentForColors();
412#endif
413}
414
415bool Process::FileDescriptorHasColors(int fd) {
416 // A file descriptor has colors if it is displayed and the terminal has
417 // colors.
418 return FileDescriptorIsDisplayed(fd) && terminalHasColors(fd);
419}
420
421bool Process::StandardOutHasColors() {
422 return FileDescriptorHasColors(STDOUT_FILENO);
423}
424
425bool Process::StandardErrHasColors() {
426 return FileDescriptorHasColors(STDERR_FILENO);
427}
428
429void Process::UseANSIEscapeCodes(bool /*enable*/) {
430 // No effect.
431}
432
433bool Process::ColorNeedsFlush() {
434 // No, we use ANSI escape sequences.
435 return false;
436}
437
438const char *Process::OutputColor(char code, bool bold, bool bg) {
439 return colorcodes[bg ? 1 : 0][bold ? 1 : 0][code & 15];
440}
441
442const char *Process::OutputBold(bool bg) { return "\033[1m"; }
443
444const char *Process::OutputReverse() { return "\033[7m"; }
445
446const char *Process::ResetColor() { return "\033[0m"; }
447
448#if !HAVE_DECL_ARC4RANDOM
449static unsigned GetRandomNumberSeed() {
450 // Attempt to get the initial seed from /dev/urandom, if possible.
451 int urandomFD = open("/dev/urandom", O_RDONLY);
452
453 if (urandomFD != -1) {
454 unsigned seed;
455 // Don't use a buffered read to avoid reading more data
456 // from /dev/urandom than we need.
457 int count = read(urandomFD, (void *)&seed, sizeof(seed));
458
459 close(urandomFD);
460
461 // Return the seed if the read was successful.
462 if (count == sizeof(seed))
463 return seed;
464 }
465
466 // Otherwise, swizzle the current time and the process ID to form a reasonable
467 // seed.
468 const auto Now = std::chrono::high_resolution_clock::now();
469 return hash_combine(Now.time_since_epoch().count(), ::getpid());
470}
471#endif
472
474#if HAVE_DECL_ARC4RANDOM
475 return arc4random();
476#else
477 static int x = (static_cast<void>(::srand(GetRandomNumberSeed())), 0);
478 (void)x;
479 return ::rand();
480#endif
481}
482
483[[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
std::error_code errnoAsErrorCode()
Helper to get errno as an std::error_code.
Definition: Error.h:1193