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/Optional.h" 29 #include "llvm/Config/llvm-config.h" 30 #include "llvm/Support/Allocator.h" 31 #include "llvm/Support/Chrono.h" 32 #include "llvm/Support/DataTypes.h" 33 #include <system_error> 34 35 namespace llvm { 36 template <typename T> class ArrayRef; 37 class StringRef; 38 39 namespace sys { 40 41 42 /// \brief A collection of legacy interfaces for querying information about the 43 /// current executing process. 44 class Process { 45 public: 46 static unsigned getPageSize(); 47 48 /// \brief Return process memory usage. 49 /// This static function will return the total amount of memory allocated 50 /// by the process. This only counts the memory allocated via the malloc, 51 /// calloc and realloc functions and includes any "free" holes in the 52 /// allocated space. 53 static size_t GetMallocUsage(); 54 55 /// This static function will set \p user_time to the amount of CPU time 56 /// spent in user (non-kernel) mode and \p sys_time to the amount of CPU 57 /// time spent in system (kernel) mode. If the operating system does not 58 /// support collection of these metrics, a zero duration will be for both 59 /// values. 60 /// \param elapsed Returns the system_clock::now() giving current time 61 /// \param user_time Returns the current amount of user time for the process 62 /// \param sys_time Returns the current amount of system time for the process 63 static void GetTimeUsage(TimePoint<> &elapsed, 64 std::chrono::nanoseconds &user_time, 65 std::chrono::nanoseconds &sys_time); 66 67 /// This function makes the necessary calls to the operating system to 68 /// prevent core files or any other kind of large memory dumps that can 69 /// occur when a program fails. 70 /// @brief Prevent core file generation. 71 static void PreventCoreFiles(); 72 73 /// \brief true if PreventCoreFiles has been called, false otherwise. 74 static bool AreCoreFilesPrevented(); 75 76 // This function returns the environment variable \arg name's value as a UTF-8 77 // string. \arg Name is assumed to be in UTF-8 encoding too. 78 static Optional<std::string> GetEnv(StringRef name); 79 80 /// This function searches for an existing file in the list of directories 81 /// in a PATH like environment variable, and returns the first file found, 82 /// according to the order of the entries in the PATH like environment 83 /// variable. 84 static Optional<std::string> FindInEnvPath(const std::string& EnvName, 85 const std::string& FileName); 86 87 /// This function returns a SmallVector containing the arguments passed from 88 /// the operating system to the program. This function expects to be handed 89 /// the vector passed in from main. 90 static std::error_code 91 GetArgumentVector(SmallVectorImpl<const char *> &Args, 92 ArrayRef<const char *> ArgsFromMain, 93 SpecificBumpPtrAllocator<char> &ArgAllocator); 94 95 // This functions ensures that the standard file descriptors (input, output, 96 // and error) are properly mapped to a file descriptor before we use any of 97 // them. This should only be called by standalone programs, library 98 // components should not call this. 99 static std::error_code FixupStandardFileDescriptors(); 100 101 // This function safely closes a file descriptor. It is not safe to retry 102 // close(2) when it returns with errno equivalent to EINTR; this is because 103 // *nixen cannot agree if the file descriptor is, in fact, closed when this 104 // occurs. 105 // 106 // N.B. Some operating systems, due to thread cancellation, cannot properly 107 // guarantee that it will or will not be closed one way or the other! 108 static std::error_code SafelyCloseFileDescriptor(int FD); 109 110 /// This function determines if the standard input is connected directly 111 /// to a user's input (keyboard probably), rather than coming from a file 112 /// or pipe. 113 static bool StandardInIsUserInput(); 114 115 /// This function determines if the standard output is connected to a 116 /// "tty" or "console" window. That is, the output would be displayed to 117 /// the user rather than being put on a pipe or stored in a file. 118 static bool StandardOutIsDisplayed(); 119 120 /// This function determines if the standard error is connected to a 121 /// "tty" or "console" window. That is, the output would be displayed to 122 /// the user rather than being put on a pipe or stored in a file. 123 static bool StandardErrIsDisplayed(); 124 125 /// This function determines if the given file descriptor is connected to 126 /// a "tty" or "console" window. That is, the output would be displayed to 127 /// the user rather than being put on a pipe or stored in a file. 128 static bool FileDescriptorIsDisplayed(int fd); 129 130 /// This function determines if the given file descriptor is displayd and 131 /// supports colors. 132 static bool FileDescriptorHasColors(int fd); 133 134 /// This function determines the number of columns in the window 135 /// if standard output is connected to a "tty" or "console" 136 /// window. If standard output is not connected to a tty or 137 /// console, or if the number of columns cannot be determined, 138 /// this routine returns zero. 139 static unsigned StandardOutColumns(); 140 141 /// This function determines the number of columns in the window 142 /// if standard error is connected to a "tty" or "console" 143 /// window. If standard error is not connected to a tty or 144 /// console, or if the number of columns cannot be determined, 145 /// this routine returns zero. 146 static unsigned StandardErrColumns(); 147 148 /// This function determines whether the terminal connected to standard 149 /// output supports colors. If standard output is not connected to a 150 /// terminal, this function returns false. 151 static bool StandardOutHasColors(); 152 153 /// This function determines whether the terminal connected to standard 154 /// error supports colors. If standard error is not connected to a 155 /// terminal, this function returns false. 156 static bool StandardErrHasColors(); 157 158 /// Enables or disables whether ANSI escape sequences are used to output 159 /// colors. This only has an effect on Windows. 160 /// Note: Setting this option is not thread-safe and should only be done 161 /// during initialization. 162 static void UseANSIEscapeCodes(bool enable); 163 164 /// Whether changing colors requires the output to be flushed. 165 /// This is needed on systems that don't support escape sequences for 166 /// changing colors. 167 static bool ColorNeedsFlush(); 168 169 /// This function returns the colorcode escape sequences. 170 /// If ColorNeedsFlush() is true then this function will change the colors 171 /// and return an empty escape sequence. In that case it is the 172 /// responsibility of the client to flush the output stream prior to 173 /// calling this function. 174 static const char *OutputColor(char c, bool bold, bool bg); 175 176 /// Same as OutputColor, but only enables the bold attribute. 177 static const char *OutputBold(bool bg); 178 179 /// This function returns the escape sequence to reverse forground and 180 /// background colors. 181 static const char *OutputReverse(); 182 183 /// Resets the terminals colors, or returns an escape sequence to do so. 184 static const char *ResetColor(); 185 186 /// Get the result of a process wide random number generator. The 187 /// generator will be automatically seeded in non-deterministic fashion. 188 static unsigned GetRandomNumber(); 189 }; 190 191 } 192 } 193 194 #endif 195