1 //===- llvm/Support/Program.h ------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file declares the llvm::sys::Program class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_SUPPORT_PROGRAM_H
14 #define LLVM_SUPPORT_PROGRAM_H
15 
16 #include "llvm/ADT/ArrayRef.h"
17 #include "llvm/ADT/BitVector.h"
18 #include "llvm/ADT/Optional.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/Config/llvm-config.h"
21 #include "llvm/Support/ErrorOr.h"
22 #include "llvm/Support/FileSystem.h"
23 #include <chrono>
24 #include <system_error>
25 
26 namespace llvm {
27 namespace sys {
28 
29   /// This is the OS-specific separator for PATH like environment variables:
30   // a colon on Unix or a semicolon on Windows.
31 #if defined(LLVM_ON_UNIX)
32   const char EnvPathSeparator = ':';
33 #elif defined (_WIN32)
34   const char EnvPathSeparator = ';';
35 #endif
36 
37 #if defined(_WIN32)
38   typedef unsigned long procid_t; // Must match the type of DWORD on Windows.
39   typedef void *process_t;        // Must match the type of HANDLE on Windows.
40 #else
41   typedef ::pid_t procid_t;
42   typedef procid_t process_t;
43 #endif
44 
45   /// This struct encapsulates information about a process.
46   struct ProcessInfo {
47     enum : procid_t { InvalidPid = 0 };
48 
49     procid_t Pid;      /// The process identifier.
50     process_t Process; /// Platform-dependent process object.
51 
52     /// The return code, set after execution.
53     int ReturnCode;
54 
55     ProcessInfo();
56   };
57 
58   /// This struct encapsulates information about a process execution.
59   struct ProcessStatistics {
60     std::chrono::microseconds TotalTime;
61     std::chrono::microseconds UserTime;
62     uint64_t PeakMemory = 0; ///< Maximum resident set size in KiB.
63   };
64 
65   /// Find the first executable file \p Name in \p Paths.
66   ///
67   /// This does not perform hashing as a shell would but instead stats each PATH
68   /// entry individually so should generally be avoided. Core LLVM library
69   /// functions and options should instead require fully specified paths.
70   ///
71   /// \param Name name of the executable to find. If it contains any system
72   ///   slashes, it will be returned as is.
73   /// \param Paths optional list of paths to search for \p Name. If empty it
74   ///   will use the system PATH environment instead.
75   ///
76   /// \returns The fully qualified path to the first \p Name in \p Paths if it
77   ///   exists. \p Name if \p Name has slashes in it. Otherwise an error.
78   ErrorOr<std::string>
79   findProgramByName(StringRef Name, ArrayRef<StringRef> Paths = {});
80 
81   // These functions change the specified standard stream (stdin or stdout) mode
82   // based on the Flags. They return errc::success if the specified stream was
83   // changed. Otherwise, a platform dependent error is returned.
84   std::error_code ChangeStdinMode(fs::OpenFlags Flags);
85   std::error_code ChangeStdoutMode(fs::OpenFlags Flags);
86 
87   // These functions change the specified standard stream (stdin or stdout) to
88   // binary mode. They return errc::success if the specified stream
89   // was changed. Otherwise a platform dependent error is returned.
90   std::error_code ChangeStdinToBinary();
91   std::error_code ChangeStdoutToBinary();
92 
93   /// This function executes the program using the arguments provided.  The
94   /// invoked program will inherit the stdin, stdout, and stderr file
95   /// descriptors, the environment and other configuration settings of the
96   /// invoking program.
97   /// This function waits for the program to finish, so should be avoided in
98   /// library functions that aren't expected to block. Consider using
99   /// ExecuteNoWait() instead.
100   /// \returns an integer result code indicating the status of the program.
101   /// A zero or positive value indicates the result code of the program.
102   /// -1 indicates failure to execute
103   /// -2 indicates a crash during execution or timeout
104   int ExecuteAndWait(
105       StringRef Program, ///< Path of the program to be executed. It is
106       ///< presumed this is the result of the findProgramByName method.
107       ArrayRef<StringRef> Args, ///< An array of strings that are passed to the
108       ///< program.  The first element should be the name of the program.
109       ///< The array should **not** be terminated by an empty StringRef.
110       Optional<ArrayRef<StringRef>> Env = None, ///< An optional vector of
111       ///< strings to use for the program's environment. If not provided, the
112       ///< current program's environment will be used.  If specified, the
113       ///< vector should **not** be terminated by an empty StringRef.
114       ArrayRef<Optional<StringRef>> Redirects = {}, ///<
115       ///< An array of optional paths. Should have a size of zero or three.
116       ///< If the array is empty, no redirections are performed.
117       ///< Otherwise, the inferior process's stdin(0), stdout(1), and stderr(2)
118       ///< will be redirected to the corresponding paths, if the optional path
119       ///< is present (not \c llvm::None).
120       ///< When an empty path is passed in, the corresponding file descriptor
121       ///< will be disconnected (ie, /dev/null'd) in a portable way.
122       unsigned SecondsToWait = 0, ///< If non-zero, this specifies the amount
123       ///< of time to wait for the child process to exit. If the time
124       ///< expires, the child is killed and this call returns. If zero,
125       ///< this function will wait until the child finishes or forever if
126       ///< it doesn't.
127       unsigned MemoryLimit = 0, ///< If non-zero, this specifies max. amount
128       ///< of memory can be allocated by process. If memory usage will be
129       ///< higher limit, the child is killed and this call returns. If zero
130       ///< - no memory limit.
131       std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
132       ///< string instance in which error messages will be returned. If the
133       ///< string is non-empty upon return an error occurred while invoking the
134       ///< program.
135       bool *ExecutionFailed = nullptr,
136       Optional<ProcessStatistics> *ProcStat = nullptr, ///< If non-zero,
137       /// provides a pointer to a structure in which process execution
138       /// statistics will be stored.
139       BitVector *AffinityMask = nullptr ///< CPUs or processors the new
140                                         /// program shall run on.
141   );
142 
143   /// Similar to ExecuteAndWait, but returns immediately.
144   /// @returns The \see ProcessInfo of the newly launched process.
145   /// \note On Microsoft Windows systems, users will need to either call
146   /// \see Wait until the process finished execution or win32 CloseHandle() API
147   /// on ProcessInfo.ProcessHandle to avoid memory leaks.
148   ProcessInfo ExecuteNoWait(StringRef Program, ArrayRef<StringRef> Args,
149                             Optional<ArrayRef<StringRef>> Env,
150                             ArrayRef<Optional<StringRef>> Redirects = {},
151                             unsigned MemoryLimit = 0,
152                             std::string *ErrMsg = nullptr,
153                             bool *ExecutionFailed = nullptr,
154                             BitVector *AffinityMask = nullptr);
155 
156   /// Return true if the given arguments fit within system-specific
157   /// argument length limits.
158   bool commandLineFitsWithinSystemLimits(StringRef Program,
159                                          ArrayRef<StringRef> Args);
160 
161   /// Return true if the given arguments fit within system-specific
162   /// argument length limits.
163   bool commandLineFitsWithinSystemLimits(StringRef Program,
164                                          ArrayRef<const char *> Args);
165 
166   /// File encoding options when writing contents that a non-UTF8 tool will
167   /// read (on Windows systems). For UNIX, we always use UTF-8.
168   enum WindowsEncodingMethod {
169     /// UTF-8 is the LLVM native encoding, being the same as "do not perform
170     /// encoding conversion".
171     WEM_UTF8,
172     WEM_CurrentCodePage,
173     WEM_UTF16
174   };
175 
176   /// Saves the UTF8-encoded \p contents string into the file \p FileName
177   /// using a specific encoding.
178   ///
179   /// This write file function adds the possibility to choose which encoding
180   /// to use when writing a text file. On Windows, this is important when
181   /// writing files with internationalization support with an encoding that is
182   /// different from the one used in LLVM (UTF-8). We use this when writing
183   /// response files, since GCC tools on MinGW only understand legacy code
184   /// pages, and VisualStudio tools only understand UTF-16.
185   /// For UNIX, using different encodings is silently ignored, since all tools
186   /// work well with UTF-8.
187   /// This function assumes that you only use UTF-8 *text* data and will convert
188   /// it to your desired encoding before writing to the file.
189   ///
190   /// FIXME: We use EM_CurrentCodePage to write response files for GNU tools in
191   /// a MinGW/MinGW-w64 environment, which has serious flaws but currently is
192   /// our best shot to make gcc/ld understand international characters. This
193   /// should be changed as soon as binutils fix this to support UTF16 on mingw.
194   ///
195   /// \returns non-zero error_code if failed
196   std::error_code
197   writeFileWithEncoding(StringRef FileName, StringRef Contents,
198                         WindowsEncodingMethod Encoding = WEM_UTF8);
199 
200   /// This function waits for the process specified by \p PI to finish.
201   /// \returns A \see ProcessInfo struct with Pid set to:
202   /// \li The process id of the child process if the child process has changed
203   /// state.
204   /// \li 0 if the child process has not changed state.
205   /// \note Users of this function should always check the ReturnCode member of
206   /// the \see ProcessInfo returned from this function.
207   ProcessInfo Wait(
208       const ProcessInfo &PI,  ///< The child process that should be waited on.
209       unsigned SecondsToWait, ///< If non-zero, this specifies the amount of
210       ///< time to wait for the child process to exit. If the time expires, the
211       ///< child is killed and this function returns. If zero, this function
212       ///< will perform a non-blocking wait on the child process.
213       bool WaitUntilTerminates, ///< If true, ignores \p SecondsToWait and waits
214       ///< until child has terminated.
215       std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
216       ///< string instance in which error messages will be returned. If the
217       ///< string is non-empty upon return an error occurred while invoking the
218       ///< program.
219       Optional<ProcessStatistics> *ProcStat = nullptr ///< If non-zero, provides
220       /// a pointer to a structure in which process execution statistics will be
221       /// stored.
222   );
223 
224   /// Print a command argument, and optionally quote it.
225   void printArg(llvm::raw_ostream &OS, StringRef Arg, bool Quote);
226 
227 #if defined(_WIN32)
228   /// Given a list of command line arguments, quote and escape them as necessary
229   /// to build a single flat command line appropriate for calling CreateProcess
230   /// on
231   /// Windows.
232   ErrorOr<std::wstring> flattenWindowsCommandLine(ArrayRef<StringRef> Args);
233 #endif
234   }
235 }
236 
237 #endif
238