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