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_SYSTEM_PROGRAM_H
15#define LLVM_SYSTEM_PROGRAM_H
16
17#include "llvm/Support/Path.h"
18
19namespace llvm {
20namespace sys {
21
22  // TODO: Add operations to communicate with the process, redirect its I/O,
23  // etc.
24
25  /// This class provides an abstraction for programs that are executable by the
26  /// operating system. It provides a platform generic way to find executable
27  /// programs from the path and to execute them in various ways. The sys::Path
28  /// class is used to specify the location of the Program.
29  /// @since 1.4
30  /// @brief An abstraction for finding and executing programs.
31  class Program {
32    /// Opaque handle for target specific data.
33    void *Data_;
34
35    // Noncopyable.
36    Program(const Program& other);
37    Program& operator=(const Program& other);
38
39    /// @name Methods
40    /// @{
41  public:
42
43    Program();
44    ~Program();
45
46    /// Return process ID of this program.
47    unsigned GetPid() const;
48
49    /// This function executes the program using the \p arguments provided.  The
50    /// invoked program will inherit the stdin, stdout, and stderr file
51    /// descriptors, the environment and other configuration settings of the
52    /// invoking program. If Path::executable() does not return true when this
53    /// function is called then a std::string is thrown.
54    /// @returns false in case of error, true otherwise.
55    /// @see FindProgramByName
56    /// @brief Executes the program with the given set of \p args.
57    bool Execute
58    ( const Path& path,  ///< sys::Path object providing the path of the
59      ///< program to be executed. It is presumed this is the result of
60      ///< the FindProgramByName method.
61      const char** args, ///< A vector of strings that are passed to the
62      ///< program.  The first element should be the name of the program.
63      ///< The list *must* be terminated by a null char* entry.
64      const char ** env = 0, ///< An optional vector of strings to use for
65      ///< the program's environment. If not provided, the current program's
66      ///< environment will be used.
67      const sys::Path** redirects = 0, ///< An optional array of pointers to
68      ///< Paths. If the array is null, no redirection is done. The array
69      ///< should have a size of at least three. If the pointer in the array
70      ///< are not null, then the inferior process's stdin(0), stdout(1),
71      ///< and stderr(2) will be redirected to the corresponding Paths.
72      ///< When an empty Path is passed in, the corresponding file
73      ///< descriptor will be disconnected (ie, /dev/null'd) in a portable
74      ///< way.
75      unsigned memoryLimit = 0, ///< If non-zero, this specifies max. amount
76      ///< of memory can be allocated by process. If memory usage will be
77      ///< higher limit, the child is killed and this call returns. If zero
78      ///< - no memory limit.
79      std::string* ErrMsg = 0 ///< If non-zero, provides a pointer to a string
80      ///< instance in which error messages will be returned. If the string
81      ///< is non-empty upon return an error occurred while invoking the
82      ///< program.
83      );
84
85    /// This function waits for the program to exit. This function will block
86    /// the current program until the invoked program exits.
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    /// @see Execute
92    /// @brief Waits for the program to exit.
93    int Wait
94    ( const Path& path, ///< The path to the child process executable.
95      unsigned secondsToWait, ///< If non-zero, this specifies the amount
96      ///< of time to wait for the child process to exit. If the time
97      ///< expires, the child is killed and this call returns. If zero,
98      ///< this function will wait until the child finishes or forever if
99      ///< it doesn't.
100      std::string* ErrMsg ///< If non-zero, provides a pointer to a string
101      ///< instance in which error messages will be returned. If the string
102      ///< is non-empty upon return an error occurred while waiting.
103      );
104
105    /// This function terminates the program.
106    /// @returns true if an error occurred.
107    /// @see Execute
108    /// @brief Terminates the program.
109    bool Kill
110    ( std::string* ErrMsg = 0 ///< If non-zero, provides a pointer to a string
111      ///< instance in which error messages will be returned. If the string
112      ///< is non-empty upon return an error occurred while killing the
113      ///< program.
114      );
115
116    /// This static constructor (factory) will attempt to locate a program in
117    /// the operating system's file system using some pre-determined set of
118    /// locations to search (e.g. the PATH on Unix). Paths with slashes are
119    /// returned unmodified.
120    /// @returns A Path object initialized to the path of the program or a
121    /// Path object that is empty (invalid) if the program could not be found.
122    /// @brief Construct a Program by finding it by name.
123    static Path FindProgramByName(const std::string& name);
124
125    // These methods change the specified standard stream (stdin,
126    // stdout, or stderr) to binary mode. They return true if an error
127    // occurred
128    static bool ChangeStdinToBinary();
129    static bool ChangeStdoutToBinary();
130    static bool ChangeStderrToBinary();
131
132    /// A convenience function equivalent to Program prg; prg.Execute(..);
133    /// prg.Wait(..);
134    /// @see Execute, Wait
135    static int ExecuteAndWait(const Path& path,
136                              const char** args,
137                              const char ** env = 0,
138                              const sys::Path** redirects = 0,
139                              unsigned secondsToWait = 0,
140                              unsigned memoryLimit = 0,
141                              std::string* ErrMsg = 0);
142
143    /// A convenience function equivalent to Program prg; prg.Execute(..);
144    /// @see Execute
145    static void ExecuteNoWait(const Path& path,
146                              const char** args,
147                              const char ** env = 0,
148                              const sys::Path** redirects = 0,
149                              unsigned memoryLimit = 0,
150                              std::string* ErrMsg = 0);
151
152    /// @}
153
154  };
155}
156}
157
158#endif
159