1//===- llvm/Support/Program.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//
10// This file declares the llvm::sys::Program class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_PROGRAM_H
15#define LLVM_SUPPORT_PROGRAM_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/Optional.h"
19#include "llvm/ADT/StringRef.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 (LLVM_ON_WIN32)
31  const char EnvPathSeparator = ';';
32#endif
33
34/// @brief This struct encapsulates information about a process.
35struct ProcessInfo {
36#if defined(LLVM_ON_UNIX)
37  typedef pid_t ProcessId;
38#elif defined(LLVM_ON_WIN32)
39  typedef unsigned long ProcessId; // Must match the type of DWORD on Windows.
40  typedef void * HANDLE; // Must match the type of HANDLE on Windows.
41  /// The handle to the process (available on Windows only).
42  HANDLE ProcessHandle;
43#else
44#error "ProcessInfo is not defined for this platform!"
45#endif
46
47  enum : ProcessId { InvalidPid = 0 };
48
49  /// The process identifier.
50  ProcessId Pid;
51
52  /// The return code, set after execution.
53  int ReturnCode;
54
55  ProcessInfo();
56};
57
58  /// \brief Find the first executable file \p Name in \p Paths.
59  ///
60  /// This does not perform hashing as a shell would but instead stats each PATH
61  /// entry individually so should generally be avoided. Core LLVM library
62  /// functions and options should instead require fully specified paths.
63  ///
64  /// \param Name name of the executable to find. If it contains any system
65  ///   slashes, it will be returned as is.
66  /// \param Paths optional list of paths to search for \p Name. If empty it
67  ///   will use the system PATH environment instead.
68  ///
69  /// \returns The fully qualified path to the first \p Name in \p Paths if it
70  ///   exists. \p Name if \p Name has slashes in it. Otherwise an error.
71  ErrorOr<std::string>
72  findProgramByName(StringRef Name, ArrayRef<StringRef> Paths = {});
73
74  // These functions change the specified standard stream (stdin or stdout) to
75  // binary mode. They return errc::success if the specified stream
76  // was changed. Otherwise a platform dependent error is returned.
77  std::error_code ChangeStdinToBinary();
78  std::error_code ChangeStdoutToBinary();
79
80  /// This function executes the program using the arguments provided.  The
81  /// invoked program will inherit the stdin, stdout, and stderr file
82  /// descriptors, the environment and other configuration settings of the
83  /// invoking program.
84  /// This function waits for the program to finish, so should be avoided in
85  /// library functions that aren't expected to block. Consider using
86  /// ExecuteNoWait() instead.
87  /// \returns an integer result code indicating the status of the program.
88  /// A zero or positive value indicates the result code of the program.
89  /// -1 indicates failure to execute
90  /// -2 indicates a crash during execution or timeout
91  int ExecuteAndWait(
92      StringRef Program, ///< Path of the program to be executed. It is
93      ///< presumed this is the result of the findProgramByName method.
94      const char **Args, ///< A vector of strings that are passed to the
95      ///< program.  The first element should be the name of the program.
96      ///< The list *must* be terminated by a null char* entry.
97      const char **Env = nullptr, ///< An optional vector of strings to use for
98      ///< the program's environment. If not provided, the current program's
99      ///< environment will be used.
100      ArrayRef<Optional<StringRef>> Redirects = {}, ///<
101      ///< An array of optional paths. Should have a size of zero or three.
102      ///< If the array is empty, no redirections are performed.
103      ///< Otherwise, the inferior process's stdin(0), stdout(1), and stderr(2)
104      ///< will be redirected to the corresponding paths, if the optional path
105      ///< is present (not \c llvm::None).
106      ///< When an empty path is passed in, the corresponding file descriptor
107      ///< will be disconnected (ie, /dev/null'd) in a portable way.
108      unsigned SecondsToWait = 0, ///< If non-zero, this specifies the amount
109      ///< of time to wait for the child process to exit. If the time
110      ///< expires, the child is killed and this call returns. If zero,
111      ///< this function will wait until the child finishes or forever if
112      ///< it doesn't.
113      unsigned MemoryLimit = 0, ///< If non-zero, this specifies max. amount
114      ///< of memory can be allocated by process. If memory usage will be
115      ///< higher limit, the child is killed and this call returns. If zero
116      ///< - no memory limit.
117      std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
118      ///< string instance in which error messages will be returned. If the
119      ///< string is non-empty upon return an error occurred while invoking the
120      ///< program.
121      bool *ExecutionFailed = nullptr);
122
123  /// Similar to ExecuteAndWait, but returns immediately.
124  /// @returns The \see ProcessInfo of the newly launced process.
125  /// \note On Microsoft Windows systems, users will need to either call
126  /// \see Wait until the process finished execution or win32 CloseHandle() API
127  /// on ProcessInfo.ProcessHandle to avoid memory leaks.
128  ProcessInfo ExecuteNoWait(StringRef Program, const char **Args,
129                            const char **Env = nullptr,
130                            ArrayRef<Optional<StringRef>> Redirects = {},
131                            unsigned MemoryLimit = 0,
132                            std::string *ErrMsg = nullptr,
133                            bool *ExecutionFailed = nullptr);
134
135  /// Return true if the given arguments fit within system-specific
136  /// argument length limits.
137  bool commandLineFitsWithinSystemLimits(StringRef Program,
138                                         ArrayRef<const char *> Args);
139
140  /// File encoding options when writing contents that a non-UTF8 tool will
141  /// read (on Windows systems). For UNIX, we always use UTF-8.
142  enum WindowsEncodingMethod {
143    /// UTF-8 is the LLVM native encoding, being the same as "do not perform
144    /// encoding conversion".
145    WEM_UTF8,
146    WEM_CurrentCodePage,
147    WEM_UTF16
148  };
149
150  /// Saves the UTF8-encoded \p contents string into the file \p FileName
151  /// using a specific encoding.
152  ///
153  /// This write file function adds the possibility to choose which encoding
154  /// to use when writing a text file. On Windows, this is important when
155  /// writing files with internationalization support with an encoding that is
156  /// different from the one used in LLVM (UTF-8). We use this when writing
157  /// response files, since GCC tools on MinGW only understand legacy code
158  /// pages, and VisualStudio tools only understand UTF-16.
159  /// For UNIX, using different encodings is silently ignored, since all tools
160  /// work well with UTF-8.
161  /// This function assumes that you only use UTF-8 *text* data and will convert
162  /// it to your desired encoding before writing to the file.
163  ///
164  /// FIXME: We use EM_CurrentCodePage to write response files for GNU tools in
165  /// a MinGW/MinGW-w64 environment, which has serious flaws but currently is
166  /// our best shot to make gcc/ld understand international characters. This
167  /// should be changed as soon as binutils fix this to support UTF16 on mingw.
168  ///
169  /// \returns non-zero error_code if failed
170  std::error_code
171  writeFileWithEncoding(StringRef FileName, StringRef Contents,
172                        WindowsEncodingMethod Encoding = WEM_UTF8);
173
174  /// This function waits for the process specified by \p PI to finish.
175  /// \returns A \see ProcessInfo struct with Pid set to:
176  /// \li The process id of the child process if the child process has changed
177  /// state.
178  /// \li 0 if the child process has not changed state.
179  /// \note Users of this function should always check the ReturnCode member of
180  /// the \see ProcessInfo returned from this function.
181  ProcessInfo Wait(
182      const ProcessInfo &PI, ///< The child process that should be waited on.
183      unsigned SecondsToWait, ///< If non-zero, this specifies the amount of
184      ///< time to wait for the child process to exit. If the time expires, the
185      ///< child is killed and this function returns. If zero, this function
186      ///< will perform a non-blocking wait on the child process.
187      bool WaitUntilTerminates, ///< If true, ignores \p SecondsToWait and waits
188      ///< until child has terminated.
189      std::string *ErrMsg = nullptr ///< If non-zero, provides a pointer to a
190      ///< string instance in which error messages will be returned. If the
191      ///< string is non-empty upon return an error occurred while invoking the
192      ///< program.
193      );
194  }
195}
196
197#endif
198