1 | /**********************************************************************
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2 | *
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3 | * os_process_unix.cpp -- Unix version of osprocess. See os_process.h
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4 | * for more details
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5 | *
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6 | * Copyright (C) 2010 The New Zealand Digital Library Project
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7 | *
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8 | * A component of the Greenstone digital library software
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9 | * from the New Zealand Digital Library Project at the
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10 | * University of Waikato, New Zealand.
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11 | *
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12 | * This program is free software; you can redistribute it and/or modify
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13 | * it under the terms of the GNU General Public License as published by
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14 | * the Free Software Foundation; either version 2 of the License, or
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15 | * (at your option) any later version.
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16 | *
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17 | * This program is distributed in the hope that it will be useful,
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18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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20 | * GNU General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, write to the Free Software
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24 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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25 | *
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26 | *********************************************************************/
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27 |
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28 | #ifndef __WIN32__ // i.e Unix
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29 |
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30 | #if defined(GSDL_USE_OBJECTSPACE)
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31 | # include <ospace/std/iostream>
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32 | #elif defined(GSDL_USE_IOS_H)
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33 | # include <iostream.h>
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34 | #else
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35 | # include <iostream>
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36 | using namespace std;
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37 | #endif
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38 |
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39 | #include <unistd.h>
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40 | #include <sys/wait.h>
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41 |
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42 | #include "os_process_unix.h"
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43 |
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44 | osprocessunix::osprocessunix(OSProcessPipeMode mode,
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45 | char* prog_name, char* argv[], char* envp[])
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46 | : child_stdout_read_(-1), child_stdin_write_(-1),
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47 | osprocess(mode,prog_name,argv,envp)
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48 | {
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49 |
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50 | // Create a pipe for the child process's STDOUT.
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51 | int stdout_pipe_fd[2];
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52 |
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53 | if (pipe(stdout_pipe_fd)!=0) {
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54 | cerr << "osprocessunix::osprocessunix(): Failed to create stdout pipe for child process" << endl;
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55 | return;
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56 | }
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57 |
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58 | child_stdout_read_ = stdout_pipe_fd[READ_PIPE_INDEX];
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59 | int child_stdout_write = stdout_pipe_fd[WRITE_PIPE_INDEX];
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60 |
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61 |
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62 | // Create a pipe for the child process's STDIN.
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63 | int stdin_pipe_fd[2];
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64 |
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65 | if (pipe(stdin_pipe_fd)!=0) {
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66 | cerr << "osprocessunix::osprocessunix(): Failed to create stdin pipe for child process" << endl;
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67 | return;
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68 | }
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69 |
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70 | int child_stdin_read = stdin_pipe_fd[READ_PIPE_INDEX];
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71 | child_stdin_write_ = stdin_pipe_fd[WRITE_PIPE_INDEX];
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72 |
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73 |
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74 | pid_ = fork();
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75 | if (pid_ < 0) {
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76 | cerr << "osprocessunix::osprocessunix(): Failed to create child process" << endl;
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77 | return;
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78 | }
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79 |
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80 | if (pid_ == 0) {
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81 | // Child process
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82 |
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83 | // Sort out input pipe
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84 | // child has no buisness accessing write end of input pipe => close
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85 | ::close(child_stdin_write_);
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86 | child_stdin_write_=-1;
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87 |
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88 | if ((mode == uniWrite) || (mode == biReadWrite)) {
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89 | // wire up child's stdin read so its input comes from the parent's pipe
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90 | dup2(child_stdin_read, FD_STDIN);
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91 | }
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92 | else {
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93 | // Parent is doing uniRead, which means we're not interested
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94 | // in the child reading any input from the parent
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95 | // => child input remains coming from stdin
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96 | ::close(child_stdin_read);
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97 | }
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98 |
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99 | // Sort out output pipe
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100 | // child has no buisness accessing read end of output pipe => close
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101 | ::close(child_stdout_read_);
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102 | child_stdout_read_=-1;
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103 |
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104 | if ((mode == uniRead) || (mode == biReadWrite)) {
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105 | // wire up child's stdout write so it is send down the pipe to the parent
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106 | dup2(child_stdout_write, FD_STDOUT);
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107 | }
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108 | else {
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109 | // Parent is doing uniWrite, which means we're not interested
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110 | // in any output produced by the child process
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111 | // => child output remains going to stdout
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112 | ::close(child_stdout_write);
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113 | }
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114 |
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115 |
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116 | // Used to be execve(), but this would appear not to search path for
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117 | // 'prog_name'. The alternative execvp() does search PATH and so is
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118 | // more compatible with how CreateProcess works for Windows
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119 |
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120 | // Need to connect envp with externally defined '**environ' ??
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121 |
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122 | execvp(prog_name,argv);
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123 |
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124 | }
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125 | else {
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126 | // Parent process
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127 |
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128 | // Sort out input pipe
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129 | // parent has no buisness accessing read end of input pipe => close
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130 | ::close(child_stdin_read);
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131 |
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132 | // Sort out output pipe
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133 | // parent has no buisness accessing write end of output pipe => close
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134 | ::close(child_stdout_write);
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135 |
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136 |
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137 | switch(mode)
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138 | {
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139 | case uniRead:
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140 | ::close(child_stdin_write_);
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141 | child_stdin_write_ = -1;
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142 | break;
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143 | case uniWrite:
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144 | ::close(child_stdout_read_);
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145 | child_stdout_read_ = -1;
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146 | break;
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147 | case biReadWrite:
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148 | // nothing to do
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149 | // the pipes are set up just the way we want them
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150 | break;
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151 | }
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152 | }
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153 | }
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154 |
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155 | osprocessunix::~osprocessunix()
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156 | {
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157 | // close any file handles that are still open
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158 | close();
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159 | }
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160 |
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161 |
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162 | int osprocessunix::write(char* buffer, const int buffer_len)
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163 | {
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164 |
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165 | int actual_write_len = ::write(child_stdin_write_, buffer, buffer_len);
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166 |
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167 | if (actual_write_len<0) {
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168 | cerr << "osproessunix::write() Error: failed to write data" << endl;
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169 | }
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170 |
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171 | return actual_write_len;
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172 | }
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173 |
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174 | int osprocessunix::read(char* buffer, const int buffer_len)
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175 | {
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176 | int actual_read_len = ::read(child_stdout_read_, buffer, buffer_len);
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177 |
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178 | if (actual_read_len<0) {
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179 | cerr << "osproessunix::read() Error: failed to read data" << endl;
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180 | }
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181 |
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182 | return actual_read_len;
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183 | }
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184 |
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185 |
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186 | void osprocessunix::wait()
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187 | {
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188 | int child_status;
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189 | //cerr << "**** waiting ..." << endl;
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190 | ::waitpid(pid_,&child_status,0);
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191 |
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192 | //cerr << "*** exit status = " << WEXITSTATUS(child_status) << endl;
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193 |
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194 | //cerr << "**** done" << endl;
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195 | }
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196 |
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197 |
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198 | bool osprocessunix::close_write_pipe(OSProcessWarnStatus warn_status)
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199 | {
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200 | int write_close_rv = 0;
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201 |
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202 | if (child_stdin_write_ != -1) {
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203 | write_close_rv = ::close(child_stdin_write_);
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204 | child_stdin_write_ = -1;
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205 | }
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206 | else if (warn_status == withWarning) {
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207 | cerr << "osprocessunix::close_write_pipe(): Warning - Tried to close already closed pipe" << endl;
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208 | }
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209 |
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210 | return (write_close_rv==0);
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211 | }
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212 |
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213 |
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214 | bool osprocessunix::close_read_pipe(OSProcessWarnStatus warn_status)
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215 | {
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216 | int read_close_rv = 0;
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217 |
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218 | if (child_stdout_read_ != -1) {
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219 | read_close_rv = ::close(child_stdout_read_);
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220 | child_stdout_read_ = -1;
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221 | }
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222 | else if (warn_status == withWarning) {
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223 | cerr << "osprocessunix::close_read_pipe(): Warning - Tried to close already closed pipe" << endl;
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224 | }
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225 |
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226 | return (read_close_rv==0);
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227 | }
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228 |
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229 |
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230 |
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231 |
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232 |
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233 |
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234 | #endif
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