1//===- llvm/Support/Process.h -----------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9/// \file
10///
11/// Provides a library for accessing information about this process and other
12/// processes on the operating system. Also provides means of spawning
13/// subprocess for commands. The design of this library is modeled after the
14/// proposed design of the Boost.Process library, and is design specifically to
15/// follow the style of standard libraries and potentially become a proposal
16/// for a standard library.
17///
18/// This file declares the llvm::sys::Process class which contains a collection
19/// of legacy static interfaces for extracting various information about the
20/// current process. The goal is to migrate users of this API over to the new
21/// interfaces.
22///
23//===----------------------------------------------------------------------===//
24
25#ifndef LLVM_SUPPORT_PROCESS_H
26#define LLVM_SUPPORT_PROCESS_H
27
28#include "llvm/ADT/ArrayRef.h"
29#include "llvm/ADT/Optional.h"
30#include "llvm/Config/llvm-config.h"
31#include "llvm/Support/Allocator.h"
32#include "llvm/Support/DataTypes.h"
33#include "llvm/Support/TimeValue.h"
34#include <system_error>
35
36namespace llvm {
37class StringRef;
38
39namespace sys {
40
41class self_process;
42
43/// \brief Generic base class which exposes information about an operating
44/// system process.
45///
46/// This base class is the core interface behind any OS process. It exposes
47/// methods to query for generic information about a particular process.
48///
49/// Subclasses implement this interface based on the mechanisms available, and
50/// can optionally expose more interfaces unique to certain process kinds.
51class process {
52protected:
53  /// \brief Only specific subclasses of process objects can be destroyed.
54  virtual ~process();
55
56public:
57  /// \brief Operating system specific type to identify a process.
58  ///
59  /// Note that the windows one is defined to 'unsigned long' as this is the
60  /// documented type for DWORD on windows, and we don't want to pull in the
61  /// Windows headers here.
62#if defined(LLVM_ON_UNIX)
63  typedef pid_t id_type;
64#elif defined(LLVM_ON_WIN32)
65  typedef unsigned long id_type; // Must match the type of DWORD.
66#else
67#error Unsupported operating system.
68#endif
69
70  /// \brief Get the operating system specific identifier for this process.
71  virtual id_type get_id() = 0;
72
73  /// \brief Get the user time consumed by this process.
74  ///
75  /// Note that this is often an approximation and may be zero on platforms
76  /// where we don't have good support for the functionality.
77  virtual TimeValue get_user_time() const = 0;
78
79  /// \brief Get the system time consumed by this process.
80  ///
81  /// Note that this is often an approximation and may be zero on platforms
82  /// where we don't have good support for the functionality.
83  virtual TimeValue get_system_time() const = 0;
84
85  /// \brief Get the wall time consumed by this process.
86  ///
87  /// Note that this is often an approximation and may be zero on platforms
88  /// where we don't have good support for the functionality.
89  virtual TimeValue get_wall_time() const = 0;
90
91  /// \name Static factory routines for processes.
92  /// @{
93
94  /// \brief Get the process object for the current process.
95  static self_process *get_self();
96
97  /// @}
98
99};
100
101/// \brief The specific class representing the current process.
102///
103/// The current process can both specialize the implementation of the routines
104/// and can expose certain information not available for other OS processes.
105class self_process : public process {
106  friend class process;
107
108  /// \brief Private destructor, as users shouldn't create objects of this
109  /// type.
110  virtual ~self_process();
111
112public:
113  id_type get_id() override;
114  TimeValue get_user_time() const override;
115  TimeValue get_system_time() const override;
116  TimeValue get_wall_time() const override;
117
118  /// \name Process configuration (sysconf on POSIX)
119  /// @{
120
121  /// \brief Get the virtual memory page size.
122  ///
123  /// Query the operating system for this process's page size.
124  size_t page_size() const { return PageSize; };
125
126  /// @}
127
128private:
129  /// \name Cached process state.
130  /// @{
131
132  /// \brief Cached page size, this cannot vary during the life of the process.
133  size_t PageSize;
134
135  /// @}
136
137  /// \brief Constructor, used by \c process::get_self() only.
138  self_process();
139};
140
141
142/// \brief A collection of legacy interfaces for querying information about the
143/// current executing process.
144class Process {
145public:
146  /// \brief Return process memory usage.
147  /// This static function will return the total amount of memory allocated
148  /// by the process. This only counts the memory allocated via the malloc,
149  /// calloc and realloc functions and includes any "free" holes in the
150  /// allocated space.
151  static size_t GetMallocUsage();
152
153  /// This static function will set \p user_time to the amount of CPU time
154  /// spent in user (non-kernel) mode and \p sys_time to the amount of CPU
155  /// time spent in system (kernel) mode.  If the operating system does not
156  /// support collection of these metrics, a zero TimeValue will be for both
157  /// values.
158  /// \param elapsed Returns the TimeValue::now() giving current time
159  /// \param user_time Returns the current amount of user time for the process
160  /// \param sys_time Returns the current amount of system time for the process
161  static void GetTimeUsage(TimeValue &elapsed, TimeValue &user_time,
162                           TimeValue &sys_time);
163
164  /// This function makes the necessary calls to the operating system to
165  /// prevent core files or any other kind of large memory dumps that can
166  /// occur when a program fails.
167  /// @brief Prevent core file generation.
168  static void PreventCoreFiles();
169
170  // This function returns the environment variable \arg name's value as a UTF-8
171  // string. \arg Name is assumed to be in UTF-8 encoding too.
172  static Optional<std::string> GetEnv(StringRef name);
173
174  /// This function searches for an existing file in the list of directories
175  /// in a PATH like environment variable, and returns the first file found,
176  /// according to the order of the entries in the PATH like environment
177  /// variable.
178  static Optional<std::string> FindInEnvPath(const std::string& EnvName,
179                                             const std::string& FileName);
180
181  /// This function returns a SmallVector containing the arguments passed from
182  /// the operating system to the program.  This function expects to be handed
183  /// the vector passed in from main.
184  static std::error_code
185  GetArgumentVector(SmallVectorImpl<const char *> &Args,
186                    ArrayRef<const char *> ArgsFromMain,
187                    SpecificBumpPtrAllocator<char> &ArgAllocator);
188
189  /// This function determines if the standard input is connected directly
190  /// to a user's input (keyboard probably), rather than coming from a file
191  /// or pipe.
192  static bool StandardInIsUserInput();
193
194  /// This function determines if the standard output is connected to a
195  /// "tty" or "console" window. That is, the output would be displayed to
196  /// the user rather than being put on a pipe or stored in a file.
197  static bool StandardOutIsDisplayed();
198
199  /// This function determines if the standard error is connected to a
200  /// "tty" or "console" window. That is, the output would be displayed to
201  /// the user rather than being put on a pipe or stored in a file.
202  static bool StandardErrIsDisplayed();
203
204  /// This function determines if the given file descriptor is connected to
205  /// a "tty" or "console" window. That is, the output would be displayed to
206  /// the user rather than being put on a pipe or stored in a file.
207  static bool FileDescriptorIsDisplayed(int fd);
208
209  /// This function determines if the given file descriptor is displayd and
210  /// supports colors.
211  static bool FileDescriptorHasColors(int fd);
212
213  /// This function determines the number of columns in the window
214  /// if standard output is connected to a "tty" or "console"
215  /// window. If standard output is not connected to a tty or
216  /// console, or if the number of columns cannot be determined,
217  /// this routine returns zero.
218  static unsigned StandardOutColumns();
219
220  /// This function determines the number of columns in the window
221  /// if standard error is connected to a "tty" or "console"
222  /// window. If standard error is not connected to a tty or
223  /// console, or if the number of columns cannot be determined,
224  /// this routine returns zero.
225  static unsigned StandardErrColumns();
226
227  /// This function determines whether the terminal connected to standard
228  /// output supports colors. If standard output is not connected to a
229  /// terminal, this function returns false.
230  static bool StandardOutHasColors();
231
232  /// This function determines whether the terminal connected to standard
233  /// error supports colors. If standard error is not connected to a
234  /// terminal, this function returns false.
235  static bool StandardErrHasColors();
236
237  /// Enables or disables whether ANSI escape sequences are used to output
238  /// colors. This only has an effect on Windows.
239  /// Note: Setting this option is not thread-safe and should only be done
240  /// during initialization.
241  static void UseANSIEscapeCodes(bool enable);
242
243  /// Whether changing colors requires the output to be flushed.
244  /// This is needed on systems that don't support escape sequences for
245  /// changing colors.
246  static bool ColorNeedsFlush();
247
248  /// This function returns the colorcode escape sequences.
249  /// If ColorNeedsFlush() is true then this function will change the colors
250  /// and return an empty escape sequence. In that case it is the
251  /// responsibility of the client to flush the output stream prior to
252  /// calling this function.
253  static const char *OutputColor(char c, bool bold, bool bg);
254
255  /// Same as OutputColor, but only enables the bold attribute.
256  static const char *OutputBold(bool bg);
257
258  /// This function returns the escape sequence to reverse forground and
259  /// background colors.
260  static const char *OutputReverse();
261
262  /// Resets the terminals colors, or returns an escape sequence to do so.
263  static const char *ResetColor();
264
265  /// Get the result of a process wide random number generator. The
266  /// generator will be automatically seeded in non-deterministic fashion.
267  static unsigned GetRandomNumber();
268};
269
270}
271}
272
273#endif
274