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/Support/Allocator.h" 30 #include "llvm/Support/Chrono.h" 31 #include "llvm/Support/DataTypes.h" 32 #include <system_error> 33 34 namespace llvm { 35 template <typename T> class ArrayRef; 36 class StringRef; 37 38 namespace sys { 39 40 41 /// A collection of legacy interfaces for querying information about the 42 /// current executing process. 43 class Process { 44 public: 45 static unsigned getPageSize(); 46 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 51 /// allocated space. 52 static size_t GetMallocUsage(); 53 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 58 /// values. 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); 65 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(); 71 72 /// true if PreventCoreFiles has been called, false otherwise. 73 static bool AreCoreFilesPrevented(); 74 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); 78 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 84 /// considered. 85 static Optional<std::string> FindInEnvPath(StringRef EnvName, 86 StringRef FileName, 87 ArrayRef<std::string> IgnoreList); 88 89 static Optional<std::string> FindInEnvPath(StringRef EnvName, 90 StringRef FileName); 91 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(); 97 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 101 // occurs. 102 // 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); 106 107 /// This function determines if the standard input is connected directly 108 /// to a user's input (keyboard probably), rather than coming from a file 109 /// or pipe. 110 static bool StandardInIsUserInput(); 111 112 /// 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(); 116 117 /// 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(); 121 122 /// 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); 126 127 /// This function determines if the given file descriptor is displayd and 128 /// supports colors. 129 static bool FileDescriptorHasColors(int fd); 130 131 /// 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(); 137 138 /// 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(); 144 145 /// 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(); 149 150 /// 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(); 154 155 /// 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); 160 161 /// Whether changing colors requires the output to be flushed. 162 /// This is needed on systems that don't support escape sequences for 163 /// changing colors. 164 static bool ColorNeedsFlush(); 165 166 /// 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); 172 173 /// Same as OutputColor, but only enables the bold attribute. 174 static const char *OutputBold(bool bg); 175 176 /// This function returns the escape sequence to reverse forground and 177 /// background colors. 178 static const char *OutputReverse(); 179 180 /// Resets the terminals colors, or returns an escape sequence to do so. 181 static const char *ResetColor(); 182 183 /// 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(); 186 }; 187 188 } 189 } 190 191 #endif 192