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/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>
43 /// \brief Generic base class which exposes information about an operating
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.
49 /// Subclasses implement this interface based on the mechanisms available, and
50 /// can optionally expose more interfaces unique to certain process kinds.
53 /// \brief Only specific subclasses of process objects can be destroyed.
57 /// \brief Operating system specific type to identify a process.
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.
67 #error Unsupported operating system.
70 /// \brief Get the operating system specific identifier for this process.
71 virtual id_type get_id() = 0;
73 /// \brief Get the user time consumed by this process.
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;
79 /// \brief Get the system time consumed by this process.
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;
85 /// \brief Get the wall time consumed by this process.
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;
91 /// \name Static factory routines for processes.
94 /// \brief Get the process object for the current process.
95 static self_process *get_self();
101 /// \brief The specific class representing the current process.
103 /// The current process can both specialize the implementation of the routines
104 /// and can expose certain information not available for other OS processes.
105 class self_process : public process {
106 friend class process;
108 /// \brief Private destructor, as users shouldn't create objects of this
110 virtual ~self_process();
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;
118 /// \name Process configuration (sysconf on POSIX)
121 /// \brief Get the virtual memory page size.
123 /// Query the operating system for this process's page size.
124 size_t page_size() const { return PageSize; };
129 /// \name Cached process state.
132 /// \brief Cached page size, this cannot vary during the life of the process.
137 /// \brief Constructor, used by \c process::get_self() only.
142 /// \brief A collection of legacy interfaces for querying information about the
143 /// current executing process.
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
151 static size_t GetMallocUsage();
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
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);
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();
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);
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
178 static Optional<std::string> FindInEnvPath(const std::string& EnvName,
179 const std::string& FileName);
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);
189 // This functions ensures that the standard file descriptors (input, output,
190 // and error) are properly mapped to a file descriptor before we use any of
191 // them. This should only be called by standalone programs, library
192 // components should not call this.
193 static std::error_code FixupStandardFileDescriptors();
195 /// This function determines if the standard input is connected directly
196 /// to a user's input (keyboard probably), rather than coming from a file
198 static bool StandardInIsUserInput();
200 /// This function determines if the standard output is connected to a
201 /// "tty" or "console" window. That is, the output would be displayed to
202 /// the user rather than being put on a pipe or stored in a file.
203 static bool StandardOutIsDisplayed();
205 /// This function determines if the standard error is connected to a
206 /// "tty" or "console" window. That is, the output would be displayed to
207 /// the user rather than being put on a pipe or stored in a file.
208 static bool StandardErrIsDisplayed();
210 /// This function determines if the given file descriptor is connected to
211 /// a "tty" or "console" window. That is, the output would be displayed to
212 /// the user rather than being put on a pipe or stored in a file.
213 static bool FileDescriptorIsDisplayed(int fd);
215 /// This function determines if the given file descriptor is displayd and
217 static bool FileDescriptorHasColors(int fd);
219 /// This function determines the number of columns in the window
220 /// if standard output is connected to a "tty" or "console"
221 /// window. If standard output is not connected to a tty or
222 /// console, or if the number of columns cannot be determined,
223 /// this routine returns zero.
224 static unsigned StandardOutColumns();
226 /// This function determines the number of columns in the window
227 /// if standard error is connected to a "tty" or "console"
228 /// window. If standard error is not connected to a tty or
229 /// console, or if the number of columns cannot be determined,
230 /// this routine returns zero.
231 static unsigned StandardErrColumns();
233 /// This function determines whether the terminal connected to standard
234 /// output supports colors. If standard output is not connected to a
235 /// terminal, this function returns false.
236 static bool StandardOutHasColors();
238 /// This function determines whether the terminal connected to standard
239 /// error supports colors. If standard error is not connected to a
240 /// terminal, this function returns false.
241 static bool StandardErrHasColors();
243 /// Enables or disables whether ANSI escape sequences are used to output
244 /// colors. This only has an effect on Windows.
245 /// Note: Setting this option is not thread-safe and should only be done
246 /// during initialization.
247 static void UseANSIEscapeCodes(bool enable);
249 /// Whether changing colors requires the output to be flushed.
250 /// This is needed on systems that don't support escape sequences for
252 static bool ColorNeedsFlush();
254 /// This function returns the colorcode escape sequences.
255 /// If ColorNeedsFlush() is true then this function will change the colors
256 /// and return an empty escape sequence. In that case it is the
257 /// responsibility of the client to flush the output stream prior to
258 /// calling this function.
259 static const char *OutputColor(char c, bool bold, bool bg);
261 /// Same as OutputColor, but only enables the bold attribute.
262 static const char *OutputBold(bool bg);
264 /// This function returns the escape sequence to reverse forground and
265 /// background colors.
266 static const char *OutputReverse();
268 /// Resets the terminals colors, or returns an escape sequence to do so.
269 static const char *ResetColor();
271 /// Get the result of a process wide random number generator. The
272 /// generator will be automatically seeded in non-deterministic fashion.
273 static unsigned GetRandomNumber();