1 //===- llvm/Support/Process.h -----------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
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
23 //===----------------------------------------------------------------------===//
25 #ifndef LLVM_SUPPORT_PROCESS_H
26 #define LLVM_SUPPORT_PROCESS_H
28 #include "llvm/ADT/Optional.h"
29 #include "llvm/Config/llvm-config.h"
30 #include "llvm/Support/DataTypes.h"
31 #include "llvm/Support/TimeValue.h"
40 /// \brief Generic base class which exposes information about an operating
43 /// This base class is the core interface behind any OS process. It exposes
44 /// methods to query for generic information about a particular process.
46 /// Subclasses implement this interface based on the mechanisms available, and
47 /// can optionally expose more interfaces unique to certain process kinds.
50 /// \brief Only specific subclasses of process objects can be destroyed.
54 /// \brief Operating system specific type to identify a process.
56 /// Note that the windows one is defined to 'unsigned long' as this is the
57 /// documented type for DWORD on windows, and we don't want to pull in the
58 /// Windows headers here.
59 #if defined(LLVM_ON_UNIX)
60 typedef pid_t id_type;
61 #elif defined(LLVM_ON_WIN32)
62 typedef unsigned long id_type; // Must match the type of DWORD.
64 #error Unsupported operating system.
67 /// \brief Get the operating system specific identifier for this process.
68 virtual id_type get_id() = 0;
70 /// \brief Get the user time consumed by this process.
72 /// Note that this is often an approximation and may be zero on platforms
73 /// where we don't have good support for the functionality.
74 virtual TimeValue get_user_time() const = 0;
76 /// \brief Get the system time consumed by this process.
78 /// Note that this is often an approximation and may be zero on platforms
79 /// where we don't have good support for the functionality.
80 virtual TimeValue get_system_time() const = 0;
82 /// \brief Get the wall time consumed by this process.
84 /// Note that this is often an approximation and may be zero on platforms
85 /// where we don't have good support for the functionality.
86 virtual TimeValue get_wall_time() const = 0;
88 /// \name Static factory routines for processes.
91 /// \brief Get the process object for the current process.
92 static self_process *get_self();
98 /// \brief The specific class representing the current process.
100 /// The current process can both specialize the implementation of the routines
101 /// and can expose certain information not available for other OS processes.
102 class self_process : public process {
103 friend class process;
105 /// \brief Private destructor, as users shouldn't create objects of this
107 virtual ~self_process();
110 virtual id_type get_id();
111 virtual TimeValue get_user_time() const;
112 virtual TimeValue get_system_time() const;
113 virtual TimeValue get_wall_time() const;
115 /// \name Process configuration (sysconf on POSIX)
118 /// \brief Get the virtual memory page size.
120 /// Query the operating system for this process's page size.
121 size_t page_size() const { return PageSize; };
126 /// \name Cached process state.
129 /// \brief Cached page size, this cannot vary during the life of the process.
134 /// \brief Constructor, used by \c process::get_self() only.
139 /// \brief A collection of legacy interfaces for querying information about the
140 /// current executing process.
143 /// \brief Return process memory usage.
144 /// This static function will return the total amount of memory allocated
145 /// by the process. This only counts the memory allocated via the malloc,
146 /// calloc and realloc functions and includes any "free" holes in the
148 static size_t GetMallocUsage();
150 /// This static function will set \p user_time to the amount of CPU time
151 /// spent in user (non-kernel) mode and \p sys_time to the amount of CPU
152 /// time spent in system (kernel) mode. If the operating system does not
153 /// support collection of these metrics, a zero TimeValue will be for both
155 /// \param elapsed Returns the TimeValue::now() giving current time
156 /// \param user_time Returns the current amount of user time for the process
157 /// \param sys_time Returns the current amount of system time for the process
158 static void GetTimeUsage(TimeValue &elapsed, TimeValue &user_time,
159 TimeValue &sys_time);
161 /// This function makes the necessary calls to the operating system to
162 /// prevent core files or any other kind of large memory dumps that can
163 /// occur when a program fails.
164 /// @brief Prevent core file generation.
165 static void PreventCoreFiles();
167 // This function returns the environment variable \arg name's value as a UTF-8
168 // string. \arg Name is assumed to be in UTF-8 encoding too.
169 static Optional<std::string> GetEnv(StringRef name);
171 /// This function determines if the standard input is connected directly
172 /// to a user's input (keyboard probably), rather than coming from a file
174 static bool StandardInIsUserInput();
176 /// This function determines if the standard output is connected to a
177 /// "tty" or "console" window. That is, the output would be displayed to
178 /// the user rather than being put on a pipe or stored in a file.
179 static bool StandardOutIsDisplayed();
181 /// This function determines if the standard error is connected to a
182 /// "tty" or "console" window. That is, the output would be displayed to
183 /// the user rather than being put on a pipe or stored in a file.
184 static bool StandardErrIsDisplayed();
186 /// This function determines if the given file descriptor is connected to
187 /// a "tty" or "console" window. That is, the output would be displayed to
188 /// the user rather than being put on a pipe or stored in a file.
189 static bool FileDescriptorIsDisplayed(int fd);
191 /// This function determines if the given file descriptor is displayd and
193 static bool FileDescriptorHasColors(int fd);
195 /// This function determines the number of columns in the window
196 /// if standard output is connected to a "tty" or "console"
197 /// window. If standard output is not connected to a tty or
198 /// console, or if the number of columns cannot be determined,
199 /// this routine returns zero.
200 static unsigned StandardOutColumns();
202 /// This function determines the number of columns in the window
203 /// if standard error is connected to a "tty" or "console"
204 /// window. If standard error is not connected to a tty or
205 /// console, or if the number of columns cannot be determined,
206 /// this routine returns zero.
207 static unsigned StandardErrColumns();
209 /// This function determines whether the terminal connected to standard
210 /// output supports colors. If standard output is not connected to a
211 /// terminal, this function returns false.
212 static bool StandardOutHasColors();
214 /// This function determines whether the terminal connected to standard
215 /// error supports colors. If standard error is not connected to a
216 /// terminal, this function returns false.
217 static bool StandardErrHasColors();
219 /// Enables or disables whether ANSI escape sequences are used to output
220 /// colors. This only has an effect on Windows.
221 /// Note: Setting this option is not thread-safe and should only be done
222 /// during initialization.
223 static void UseANSIEscapeCodes(bool enable);
225 /// Whether changing colors requires the output to be flushed.
226 /// This is needed on systems that don't support escape sequences for
228 static bool ColorNeedsFlush();
230 /// This function returns the colorcode escape sequences.
231 /// If ColorNeedsFlush() is true then this function will change the colors
232 /// and return an empty escape sequence. In that case it is the
233 /// responsibility of the client to flush the output stream prior to
234 /// calling this function.
235 static const char *OutputColor(char c, bool bold, bool bg);
237 /// Same as OutputColor, but only enables the bold attribute.
238 static const char *OutputBold(bool bg);
240 /// This function returns the escape sequence to reverse forground and
241 /// background colors.
242 static const char *OutputReverse();
244 /// Resets the terminals colors, or returns an escape sequence to do so.
245 static const char *ResetColor();
247 /// Get the result of a process wide random number generator. The
248 /// generator will be automatically seeded in non-deterministic fashion.
249 static unsigned GetRandomNumber();