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