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