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/Support/Allocator.h"
30 #include "llvm/Support/Chrono.h"
31 #include "llvm/Support/DataTypes.h"
32 #include <system_error>
35 template <typename T> class ArrayRef;
41 /// A collection of legacy interfaces for querying information about the
42 /// current executing process.
45 static unsigned getPageSize();
47 /// Return process memory usage.
48 /// This static function will return the total amount of memory allocated
49 /// by the process. This only counts the memory allocated via the malloc,
50 /// calloc and realloc functions and includes any "free" holes in the
52 static size_t GetMallocUsage();
54 /// This static function will set \p user_time to the amount of CPU time
55 /// spent in user (non-kernel) mode and \p sys_time to the amount of CPU
56 /// time spent in system (kernel) mode. If the operating system does not
57 /// support collection of these metrics, a zero duration will be for both
59 /// \param elapsed Returns the system_clock::now() giving current time
60 /// \param user_time Returns the current amount of user time for the process
61 /// \param sys_time Returns the current amount of system time for the process
62 static void GetTimeUsage(TimePoint<> &elapsed,
63 std::chrono::nanoseconds &user_time,
64 std::chrono::nanoseconds &sys_time);
66 /// This function makes the necessary calls to the operating system to
67 /// prevent core files or any other kind of large memory dumps that can
68 /// occur when a program fails.
69 /// Prevent core file generation.
70 static void PreventCoreFiles();
72 /// true if PreventCoreFiles has been called, false otherwise.
73 static bool AreCoreFilesPrevented();
75 // This function returns the environment variable \arg name's value as a UTF-8
76 // string. \arg Name is assumed to be in UTF-8 encoding too.
77 static Optional<std::string> GetEnv(StringRef name);
79 /// This function searches for an existing file in the list of directories
80 /// in a PATH like environment variable, and returns the first file found,
81 /// according to the order of the entries in the PATH like environment
82 /// variable. If an ignore list is specified, then any folder which is in
83 /// the PATH like environment variable but is also in IgnoreList is not
85 static Optional<std::string> FindInEnvPath(StringRef EnvName,
87 ArrayRef<std::string> IgnoreList);
89 static Optional<std::string> FindInEnvPath(StringRef EnvName,
92 // This functions ensures that the standard file descriptors (input, output,
93 // and error) are properly mapped to a file descriptor before we use any of
94 // them. This should only be called by standalone programs, library
95 // components should not call this.
96 static std::error_code FixupStandardFileDescriptors();
98 // This function safely closes a file descriptor. It is not safe to retry
99 // close(2) when it returns with errno equivalent to EINTR; this is because
100 // *nixen cannot agree if the file descriptor is, in fact, closed when this
103 // N.B. Some operating systems, due to thread cancellation, cannot properly
104 // guarantee that it will or will not be closed one way or the other!
105 static std::error_code SafelyCloseFileDescriptor(int FD);
107 /// This function determines if the standard input is connected directly
108 /// to a user's input (keyboard probably), rather than coming from a file
110 static bool StandardInIsUserInput();
112 /// This function determines if the standard output is connected to a
113 /// "tty" or "console" window. That is, the output would be displayed to
114 /// the user rather than being put on a pipe or stored in a file.
115 static bool StandardOutIsDisplayed();
117 /// This function determines if the standard error is connected to a
118 /// "tty" or "console" window. That is, the output would be displayed to
119 /// the user rather than being put on a pipe or stored in a file.
120 static bool StandardErrIsDisplayed();
122 /// This function determines if the given file descriptor is connected to
123 /// a "tty" or "console" window. That is, the output would be displayed to
124 /// the user rather than being put on a pipe or stored in a file.
125 static bool FileDescriptorIsDisplayed(int fd);
127 /// This function determines if the given file descriptor is displayd and
129 static bool FileDescriptorHasColors(int fd);
131 /// This function determines the number of columns in the window
132 /// if standard output is connected to a "tty" or "console"
133 /// window. If standard output is not connected to a tty or
134 /// console, or if the number of columns cannot be determined,
135 /// this routine returns zero.
136 static unsigned StandardOutColumns();
138 /// This function determines the number of columns in the window
139 /// if standard error is connected to a "tty" or "console"
140 /// window. If standard error is not connected to a tty or
141 /// console, or if the number of columns cannot be determined,
142 /// this routine returns zero.
143 static unsigned StandardErrColumns();
145 /// This function determines whether the terminal connected to standard
146 /// output supports colors. If standard output is not connected to a
147 /// terminal, this function returns false.
148 static bool StandardOutHasColors();
150 /// This function determines whether the terminal connected to standard
151 /// error supports colors. If standard error is not connected to a
152 /// terminal, this function returns false.
153 static bool StandardErrHasColors();
155 /// Enables or disables whether ANSI escape sequences are used to output
156 /// colors. This only has an effect on Windows.
157 /// Note: Setting this option is not thread-safe and should only be done
158 /// during initialization.
159 static void UseANSIEscapeCodes(bool enable);
161 /// Whether changing colors requires the output to be flushed.
162 /// This is needed on systems that don't support escape sequences for
164 static bool ColorNeedsFlush();
166 /// This function returns the colorcode escape sequences.
167 /// If ColorNeedsFlush() is true then this function will change the colors
168 /// and return an empty escape sequence. In that case it is the
169 /// responsibility of the client to flush the output stream prior to
170 /// calling this function.
171 static const char *OutputColor(char c, bool bold, bool bg);
173 /// Same as OutputColor, but only enables the bold attribute.
174 static const char *OutputBold(bool bg);
176 /// This function returns the escape sequence to reverse forground and
177 /// background colors.
178 static const char *OutputReverse();
180 /// Resets the terminals colors, or returns an escape sequence to do so.
181 static const char *ResetColor();
183 /// Get the result of a process wide random number generator. The
184 /// generator will be automatically seeded in non-deterministic fashion.
185 static unsigned GetRandomNumber();