1 | /* |
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2 | |
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3 | clientloop.c |
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4 | |
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5 | Author: Tatu Ylonen <ylo@cs.hut.fi> |
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6 | |
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7 | Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
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8 | All rights reserved |
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9 | |
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10 | |
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11 | Created: Sat Sep 23 12:23:57 1995 ylo |
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12 | |
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13 | The main loop for the interactive session (client side). |
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14 | |
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15 | */ |
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16 | |
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17 | /* |
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18 | * $Id: clientloop.c,v 1.1.1.2 1999-03-08 17:43:26 danw Exp $ |
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19 | * $Log: not supported by cvs2svn $ |
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20 | * Revision 1.5 1998/05/23 20:21:22 kivinen |
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21 | * Changed () -> (void). |
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22 | * |
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23 | * Revision 1.4 1997/03/26 07:12:28 kivinen |
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24 | * Added HAVE_NO_TZ_IN_GETTIMEOFDAY support. |
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25 | * |
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26 | * Revision 1.3 1996/11/24 08:17:46 kivinen |
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27 | * Added all checks that check EAGAIN to check EWOULDBLOCK too. |
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28 | * |
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29 | * Revision 1.2 1996/04/22 23:45:20 huima |
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30 | * Added support for the revised channel protocol. |
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31 | * |
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32 | * Revision 1.1.1.1 1996/02/18 21:38:12 ylo |
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33 | * Imported ssh-1.2.13. |
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34 | * |
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35 | * Revision 1.1 1995/09/25 00:05:00 ylo |
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36 | * Created. This file contains the client main loop, which used |
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37 | * to be in ssh.c. |
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38 | * |
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39 | * $Endlog$ |
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40 | */ |
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41 | |
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42 | #include "includes.h" |
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43 | #include "xmalloc.h" |
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44 | #include "randoms.h" |
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45 | #include "ssh.h" |
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46 | #include "packet.h" |
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47 | #include "buffer.h" |
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48 | #include "authfd.h" |
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49 | |
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50 | /* Flag indicating whether quiet mode is on. */ |
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51 | extern int quiet_flag; |
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52 | |
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53 | /* Flag indicating that stdin should be redirected from /dev/null. */ |
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54 | extern int stdin_null_flag; |
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55 | |
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56 | /* Name of the host we are connecting to. This is the name given on the |
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57 | command line, or the HostName specified for the user-supplied name |
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58 | in a configuration file. */ |
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59 | extern char *host; |
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60 | |
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61 | #ifdef SIGWINCH |
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62 | /* Flag to indicate that we have received a window change signal which has |
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63 | not yet been processed. This will cause a message indicating the new |
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64 | window size to be sent to the server a little later. This is volatile |
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65 | because this is updated in a signal handler. */ |
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66 | static volatile int received_window_change_signal = 0; |
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67 | #endif /* SIGWINCH */ |
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68 | |
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69 | /* Terminal modes, as saved by enter_raw_mode. */ |
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70 | #ifdef USING_TERMIOS |
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71 | static struct termios saved_tio; |
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72 | #endif |
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73 | #ifdef USING_SGTTY |
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74 | static struct sgttyb saved_tio; |
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75 | #endif |
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76 | |
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77 | /* Flag indicating whether we are in raw mode. This is used by enter_raw_mode |
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78 | and leave_raw_mode. */ |
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79 | static int in_raw_mode = 0; |
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80 | |
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81 | /* Flag indicating whether the user\'s terminal is in non-blocking mode. */ |
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82 | static int in_non_blocking_mode = 0; |
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83 | |
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84 | /* Common data for the client loop code. */ |
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85 | static int escape_pending; /* Last character was the escape character */ |
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86 | static int last_was_cr; /* Last character was a newline. */ |
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87 | static int exit_status; /* Used to store the exit status of the command. */ |
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88 | static int stdin_eof; /* EOF has been encountered on standard error. */ |
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89 | static Buffer stdin_buffer; /* Buffer for stdin data. */ |
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90 | static Buffer stdout_buffer; /* Buffer for stdout data. */ |
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91 | static Buffer stderr_buffer; /* Buffer for stderr data. */ |
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92 | static unsigned int buffer_high; /* Soft max buffer size. */ |
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93 | static int max_fd; /* Maximum file descriptor number in select(). */ |
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94 | static int connection_in; /* Connection to server (input). */ |
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95 | static int connection_out; /* Connection to server (output). */ |
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96 | static unsigned long stdin_bytes, stdout_bytes, stderr_bytes; |
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97 | static int quit_pending; /* Set to non-zero to quit the client loop. */ |
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98 | static int escape_char; /* Escape character. */ |
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99 | |
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100 | /* Returns the user\'s terminal to normal mode if it had been put in raw |
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101 | mode. */ |
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102 | |
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103 | void leave_raw_mode(void) |
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104 | { |
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105 | if (!in_raw_mode) |
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106 | return; |
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107 | in_raw_mode = 0; |
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108 | #ifdef USING_TERMIOS |
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109 | if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0) |
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110 | perror("tcsetattr"); |
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111 | #endif /* USING_TERMIOS */ |
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112 | #ifdef USING_SGTTY |
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113 | if (ioctl(fileno(stdin), TIOCSETP, &saved_tio) < 0) |
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114 | perror("ioctl(stdin, TIOCSETP, ...)"); |
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115 | #endif /* USING_SGTTY */ |
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116 | |
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117 | fatal_remove_cleanup((void (*)(void *))leave_raw_mode, NULL); |
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118 | } |
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119 | |
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120 | /* Puts the user\'s terminal in raw mode. */ |
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121 | |
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122 | void enter_raw_mode(void) |
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123 | { |
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124 | #ifdef USING_TERMIOS |
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125 | struct termios tio; |
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126 | |
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127 | if (tcgetattr(fileno(stdin), &tio) < 0) |
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128 | perror("tcgetattr"); |
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129 | saved_tio = tio; |
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130 | tio.c_iflag |= IGNPAR; |
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131 | tio.c_iflag &= ~(ISTRIP|INLCR|IGNCR|ICRNL|IXON|IXANY|IXOFF); |
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132 | tio.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHONL); |
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133 | #ifdef IEXTEN |
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134 | tio.c_lflag &= ~IEXTEN; |
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135 | #endif /* IEXTEN */ |
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136 | tio.c_oflag &= ~OPOST; |
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137 | tio.c_cc[VMIN] = 1; |
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138 | tio.c_cc[VTIME] = 0; |
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139 | if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0) |
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140 | perror("tcsetattr"); |
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141 | in_raw_mode = 1; |
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142 | #endif /* USING_TERMIOS */ |
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143 | #ifdef USING_SGTTY |
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144 | struct sgttyb tio; |
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145 | |
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146 | if (ioctl(fileno(stdin), TIOCGETP, &tio) < 0) |
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147 | perror("ioctl(stdin, TIOCGETP, ...)"); |
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148 | saved_tio = tio; |
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149 | tio.sg_flags &= ~(CBREAK | ECHO | CRMOD | LCASE | TANDEM); |
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150 | tio.sg_flags |= (RAW | ANYP); |
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151 | if (ioctl(fileno(stdin), TIOCSETP, &tio) < 0) |
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152 | perror("ioctl(stdin, TIOCSETP, ...)"); |
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153 | in_raw_mode = 1; |
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154 | #endif /* USING_SGTTY */ |
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155 | |
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156 | fatal_add_cleanup((void (*)(void *))leave_raw_mode, NULL); |
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157 | } |
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158 | |
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159 | /* Puts stdin terminal in non-blocking mode. */ |
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160 | |
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161 | /* Restores stdin to blocking mode. */ |
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162 | |
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163 | void leave_non_blocking(void) |
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164 | { |
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165 | if (in_non_blocking_mode) |
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166 | { |
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167 | (void)fcntl(fileno(stdin), F_SETFL, 0); |
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168 | in_non_blocking_mode = 0; |
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169 | fatal_remove_cleanup((void (*)(void *))leave_non_blocking, NULL); |
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170 | } |
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171 | } |
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172 | |
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173 | void enter_non_blocking(void) |
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174 | { |
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175 | in_non_blocking_mode = 1; |
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176 | #if defined(O_NONBLOCK) && !defined(O_NONBLOCK_BROKEN) |
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177 | (void)fcntl(fileno(stdin), F_SETFL, O_NONBLOCK); |
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178 | #else /* O_NONBLOCK && !O_NONBLOCK_BROKEN */ |
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179 | (void)fcntl(fileno(stdin), F_SETFL, O_NDELAY); |
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180 | #endif /* O_NONBLOCK && !O_NONBLOCK_BROKEN */ |
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181 | fatal_add_cleanup((void (*)(void *))leave_non_blocking, NULL); |
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182 | } |
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183 | |
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184 | #ifdef SIGWINCH |
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185 | /* Signal handler for the window change signal (SIGWINCH). This just |
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186 | sets a flag indicating that the window has changed. */ |
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187 | |
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188 | RETSIGTYPE window_change_handler(int sig) |
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189 | { |
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190 | received_window_change_signal = 1; |
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191 | signal(SIGWINCH, window_change_handler); |
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192 | } |
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193 | #endif /* SIGWINCH */ |
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194 | |
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195 | /* Signal handler for signals that cause the program to terminate. These |
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196 | signals must be trapped to restore terminal modes. */ |
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197 | |
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198 | RETSIGTYPE signal_handler(int sig) |
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199 | { |
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200 | if (in_raw_mode) |
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201 | leave_raw_mode(); |
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202 | if (in_non_blocking_mode) |
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203 | leave_non_blocking(); |
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204 | channel_stop_listening(); |
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205 | packet_close(); |
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206 | fatal("Killed by signal %d.", sig); |
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207 | } |
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208 | |
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209 | /* Returns current time in seconds from Jan 1, 1970 with the maximum available |
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210 | resolution. */ |
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211 | |
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212 | double get_current_time(void) |
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213 | { |
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214 | #ifdef HAVE_GETTIMEOFDAY |
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215 | struct timeval tv; |
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216 | #ifdef HAVE_NO_TZ_IN_GETTIMEOFDAY |
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217 | gettimeofday(&tv); |
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218 | #else |
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219 | gettimeofday(&tv, NULL); |
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220 | #endif |
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221 | return (double)tv.tv_sec + (double)tv.tv_usec / 1000000.0; |
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222 | #else /* HAVE_GETTIMEOFDAY */ |
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223 | return (double)time(NULL); |
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224 | #endif /* HAVE_GETTIMEOFDAY */ |
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225 | } |
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226 | |
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227 | /* This is called when the interactive is entered. This checks if there |
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228 | is an EOF coming on stdin. We must check this explicitly, as select() |
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229 | does not appear to wake up when redirecting from /dev/null. */ |
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230 | |
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231 | void client_check_initial_eof_on_stdin(void) |
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232 | { |
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233 | int len; |
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234 | char buf[1]; |
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235 | |
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236 | /* If standard input is to be "redirected from /dev/null", we simply |
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237 | mark that we have seen an EOF and send an EOF message to the server. |
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238 | Otherwise, we try to read a single character; it appears that for some |
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239 | files, such /dev/null, select() never wakes up for read for this |
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240 | descriptor, which means that we never get EOF. This way we will get |
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241 | the EOF if stdin comes from /dev/null or similar. */ |
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242 | if (stdin_null_flag) |
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243 | { |
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244 | /* Fake EOF on stdin. */ |
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245 | debug("Sending eof."); |
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246 | stdin_eof = 1; |
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247 | packet_start(SSH_CMSG_EOF); |
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248 | packet_send(); |
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249 | } |
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250 | else |
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251 | { |
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252 | /* Enter non-blocking mode for stdin. */ |
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253 | enter_non_blocking(); |
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254 | |
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255 | /* Check for immediate EOF on stdin. */ |
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256 | len = read(fileno(stdin), buf, 1); |
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257 | if (len == 0) |
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258 | { |
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259 | /* EOF. Record that we have seen it and send EOF to server. */ |
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260 | debug("Sending eof."); |
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261 | stdin_eof = 1; |
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262 | packet_start(SSH_CMSG_EOF); |
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263 | packet_send(); |
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264 | } |
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265 | else |
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266 | if (len > 0) |
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267 | { |
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268 | /* Got data. We must store the data in the buffer, and also |
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269 | process it as an escape character if appropriate. */ |
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270 | if ((unsigned char)buf[0] == escape_char) |
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271 | escape_pending = 1; |
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272 | else |
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273 | { |
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274 | buffer_append(&stdin_buffer, buf, 1); |
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275 | stdin_bytes += 1; |
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276 | } |
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277 | } |
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278 | |
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279 | /* Leave non-blocking mode. */ |
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280 | leave_non_blocking(); |
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281 | } |
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282 | } |
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283 | |
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284 | /* Get packets from the connection input buffer, and process them as long |
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285 | as there are packets available. */ |
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286 | |
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287 | void client_process_buffered_input_packets(void) |
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288 | { |
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289 | int type; |
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290 | char *data; |
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291 | unsigned int data_len; |
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292 | |
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293 | /* Process any buffered packets from the server. */ |
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294 | while (!quit_pending && (type = packet_read_poll()) != SSH_MSG_NONE) |
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295 | { |
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296 | switch (type) |
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297 | { |
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298 | |
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299 | case SSH_SMSG_STDOUT_DATA: |
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300 | data = packet_get_string(&data_len); |
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301 | buffer_append(&stdout_buffer, data, data_len); |
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302 | stdout_bytes += data_len; |
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303 | memset(data, 0, data_len); |
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304 | xfree(data); |
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305 | break; |
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306 | |
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307 | case SSH_SMSG_STDERR_DATA: |
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308 | data = packet_get_string(&data_len); |
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309 | buffer_append(&stderr_buffer, data, data_len); |
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310 | stdout_bytes += data_len; |
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311 | memset(data, 0, data_len); |
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312 | xfree(data); |
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313 | break; |
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314 | |
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315 | case SSH_SMSG_EXITSTATUS: |
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316 | exit_status = packet_get_int(); |
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317 | /* Acknowledge the exit. */ |
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318 | packet_start(SSH_CMSG_EXIT_CONFIRMATION); |
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319 | packet_send(); |
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320 | /* Must wait for packet to be sent since we are exiting the |
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321 | loop. */ |
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322 | packet_write_wait(); |
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323 | /* Flag that we want to exit. */ |
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324 | quit_pending = 1; |
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325 | break; |
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326 | |
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327 | case SSH_SMSG_X11_OPEN: |
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328 | x11_input_open(); |
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329 | break; |
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330 | |
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331 | case SSH_MSG_PORT_OPEN: |
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332 | channel_input_port_open(); |
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333 | break; |
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334 | |
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335 | case SSH_SMSG_AGENT_OPEN: |
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336 | auth_input_open_request(); |
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337 | break; |
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338 | |
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339 | case SSH_MSG_CHANNEL_OPEN_CONFIRMATION: |
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340 | channel_input_open_confirmation(); |
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341 | break; |
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342 | |
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343 | case SSH_MSG_CHANNEL_OPEN_FAILURE: |
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344 | channel_input_open_failure(); |
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345 | break; |
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346 | |
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347 | case SSH_MSG_CHANNEL_DATA: |
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348 | channel_input_data(); |
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349 | break; |
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350 | |
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351 | #ifdef SUPPORT_OLD_CHANNELS |
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352 | case SSH_MSG_CHANNEL_CLOSE: |
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353 | channel_input_close(); |
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354 | break; |
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355 | |
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356 | case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION: |
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357 | channel_input_close_confirmation(); |
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358 | break; |
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359 | #else |
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360 | case SSH_MSG_CHANNEL_INPUT_EOF: |
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361 | channel_ieof(); |
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362 | break; |
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363 | |
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364 | case SSH_MSG_CHANNEL_OUTPUT_CLOSED: |
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365 | channel_oclosed(); |
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366 | break; |
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367 | #endif |
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368 | |
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369 | default: |
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370 | /* Any unknown packets received during the actual session |
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371 | cause the session to terminate. This is intended to make |
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372 | debugging easier since no confirmations are sent. Any |
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373 | compatible protocol extensions must be negotiated during |
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374 | the preparatory phase. */ |
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375 | packet_disconnect("Protocol error during session: type %d", |
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376 | type); |
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377 | } |
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378 | } |
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379 | } |
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380 | |
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381 | /* Make packets from buffered stdin data, and buffer them for sending to |
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382 | the connection. */ |
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383 | |
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384 | void client_make_packets_from_stdin_data(void) |
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385 | { |
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386 | unsigned int len; |
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387 | |
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388 | /* Send buffered stdin data to the server. */ |
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389 | while (buffer_len(&stdin_buffer) > 0 && |
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390 | packet_not_very_much_data_to_write()) |
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391 | { |
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392 | len = buffer_len(&stdin_buffer); |
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393 | if (len > 32768) |
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394 | len = 32768; /* Keep the packets at reasonable size. */ |
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395 | packet_start(SSH_CMSG_STDIN_DATA); |
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396 | packet_put_string(buffer_ptr(&stdin_buffer), len); |
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397 | packet_send(); |
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398 | buffer_consume(&stdin_buffer, len); |
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399 | /* If we have a pending EOF, send it now. */ |
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400 | if (stdin_eof && buffer_len(&stdin_buffer) == 0) |
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401 | { |
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402 | packet_start(SSH_CMSG_EOF); |
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403 | packet_send(); |
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404 | } |
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405 | } |
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406 | } |
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407 | |
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408 | /* Checks if the client window has changed, and sends a packet about it to |
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409 | the server if so. The actual change is detected elsewhere (by a software |
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410 | interrupt on Unix); this just checks the flag and sends a message if |
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411 | appropriate. */ |
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412 | |
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413 | void client_check_window_change(void) |
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414 | { |
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415 | #ifdef SIGWINCH |
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416 | /* Send possible window change message to the server. */ |
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417 | if (received_window_change_signal) |
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418 | { |
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419 | struct winsize ws; |
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420 | |
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421 | /* Clear the window change indicator. */ |
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422 | received_window_change_signal = 0; |
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423 | |
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424 | /* Read new window size. */ |
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425 | if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) >= 0) |
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426 | { |
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427 | /* Successful, send the packet now. */ |
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428 | packet_start(SSH_CMSG_WINDOW_SIZE); |
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429 | packet_put_int(ws.ws_row); |
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430 | packet_put_int(ws.ws_col); |
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431 | packet_put_int(ws.ws_xpixel); |
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432 | packet_put_int(ws.ws_ypixel); |
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433 | packet_send(); |
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434 | } |
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435 | } |
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436 | #endif /* SIGWINCH */ |
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437 | } |
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438 | |
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439 | /* Waits until the client can do something (some data becomes available on |
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440 | one of the file descriptors). */ |
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441 | |
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442 | void client_wait_until_can_do_something(fd_set *readset, fd_set *writeset) |
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443 | { |
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444 | /* Initialize select masks. */ |
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445 | FD_ZERO(readset); |
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446 | |
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447 | /* Read from the connection, unless our buffers are full. */ |
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448 | if (buffer_len(&stdout_buffer) < buffer_high && |
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449 | buffer_len(&stderr_buffer) < buffer_high && |
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450 | channel_not_very_much_buffered_data()) |
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451 | FD_SET(connection_in, readset); |
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452 | |
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453 | /* Read from stdin, unless we have seen EOF or have very much buffered |
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454 | data to send to the server. */ |
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455 | if (!stdin_eof && packet_not_very_much_data_to_write()) |
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456 | FD_SET(fileno(stdin), readset); |
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457 | |
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458 | FD_ZERO(writeset); |
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459 | |
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460 | /* Add any selections by the channel mechanism. */ |
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461 | channel_prepare_select(readset, writeset); |
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462 | |
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463 | /* Select server connection if have data to write to the server. */ |
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464 | if (packet_have_data_to_write()) |
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465 | FD_SET(connection_out, writeset); |
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466 | |
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467 | /* Select stdout if have data in buffer. */ |
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468 | if (buffer_len(&stdout_buffer) > 0) |
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469 | FD_SET(fileno(stdout), writeset); |
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470 | |
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471 | /* Select stderr if have data in buffer. */ |
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472 | if (buffer_len(&stderr_buffer) > 0) |
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473 | FD_SET(fileno(stderr), writeset); |
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474 | |
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475 | /* Update maximum file descriptor number, if appropriate. */ |
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476 | if (channel_max_fd() > max_fd) |
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477 | max_fd = channel_max_fd(); |
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478 | |
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479 | /* Wait for something to happen. This will suspend the process until |
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480 | some selected descriptor can be read, written, or has some other |
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481 | event pending. Note: if you want to implement SSH_MSG_IGNORE |
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482 | messages to fool traffic analysis, this might be the place to do |
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483 | it: just have a random timeout for the select, and send a random |
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484 | SSH_MSG_IGNORE packet when the timeout expires. */ |
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485 | if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) |
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486 | { |
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487 | char buf[100]; |
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488 | /* Some systems fail to clear these automatically. */ |
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489 | FD_ZERO(readset); |
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490 | FD_ZERO(writeset); |
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491 | if (errno == EINTR) |
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492 | return; |
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493 | /* Note: we might still have data in the buffers. */ |
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494 | sprintf(buf, "select: %.100s\r\n", strerror(errno)); |
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495 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
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496 | stderr_bytes += strlen(buf); |
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497 | quit_pending = 1; |
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498 | } |
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499 | } |
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500 | |
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501 | void client_suspend_self(void) |
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502 | { |
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503 | #ifdef SIGWINCH |
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504 | struct winsize oldws, newws; |
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505 | #endif /* SIGWINCH */ |
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506 | |
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507 | /* Flush stdout and stderr buffers. */ |
---|
508 | if (buffer_len(&stdout_buffer) > 0) |
---|
509 | write(fileno(stdout), |
---|
510 | buffer_ptr(&stdout_buffer), |
---|
511 | buffer_len(&stdout_buffer)); |
---|
512 | if (buffer_len(&stderr_buffer) > 0) |
---|
513 | write(fileno(stderr), |
---|
514 | buffer_ptr(&stderr_buffer), |
---|
515 | buffer_len(&stderr_buffer)); |
---|
516 | |
---|
517 | /* Leave raw mode. */ |
---|
518 | leave_raw_mode(); |
---|
519 | |
---|
520 | /* Free (and clear) the buffer to reduce the |
---|
521 | amount of data that gets written to swap. */ |
---|
522 | buffer_free(&stdin_buffer); |
---|
523 | buffer_free(&stdout_buffer); |
---|
524 | buffer_free(&stderr_buffer); |
---|
525 | |
---|
526 | #ifdef SIGWINCH |
---|
527 | /* Save old window size. */ |
---|
528 | ioctl(fileno(stdin), TIOCGWINSZ, &oldws); |
---|
529 | #endif /* SIGWINCH */ |
---|
530 | |
---|
531 | /* Send the suspend signal to the program |
---|
532 | itself. */ |
---|
533 | kill(getpid(), SIGTSTP); |
---|
534 | |
---|
535 | #ifdef SIGWINCH |
---|
536 | /* Check if the window size has changed. */ |
---|
537 | if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && |
---|
538 | (oldws.ws_row != newws.ws_row || oldws.ws_col != newws.ws_col || |
---|
539 | oldws.ws_xpixel != newws.ws_xpixel || |
---|
540 | oldws.ws_ypixel != newws.ws_ypixel)) |
---|
541 | received_window_change_signal = 1; |
---|
542 | #endif /* SIGWINCH */ |
---|
543 | |
---|
544 | /* OK, we have been continued by the user. |
---|
545 | Reinitialize buffers. */ |
---|
546 | buffer_init(&stdin_buffer); |
---|
547 | buffer_init(&stdout_buffer); |
---|
548 | buffer_init(&stderr_buffer); |
---|
549 | |
---|
550 | /* Re-enter raw mode. */ |
---|
551 | enter_raw_mode(); |
---|
552 | } |
---|
553 | |
---|
554 | void client_process_input(fd_set *readset) |
---|
555 | { |
---|
556 | int len, pid; |
---|
557 | char buf[8192], *s; |
---|
558 | |
---|
559 | /* Read input from the server, and add any such data to the buffer of the |
---|
560 | packet subsystem. */ |
---|
561 | if (FD_ISSET(connection_in, readset)) |
---|
562 | { |
---|
563 | /* Read as much as possible. */ |
---|
564 | len = read(connection_in, buf, sizeof(buf)); |
---|
565 | if (len == 0) |
---|
566 | { |
---|
567 | /* Received EOF. The remote host has closed the connection. */ |
---|
568 | sprintf(buf, "Connection to %.300s closed by remote host.\r\n", |
---|
569 | host); |
---|
570 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
571 | stderr_bytes += strlen(buf); |
---|
572 | quit_pending = 1; |
---|
573 | return; |
---|
574 | } |
---|
575 | |
---|
576 | /* There is a kernel bug on Solaris that causes select to sometimes |
---|
577 | wake up even though there is no data available. */ |
---|
578 | if (len < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) |
---|
579 | len = 0; |
---|
580 | |
---|
581 | if (len < 0) |
---|
582 | { |
---|
583 | /* An error has encountered. Perhaps there is a network |
---|
584 | problem. */ |
---|
585 | sprintf(buf, "Read from remote host %.300s: %.100s\r\n", |
---|
586 | host, strerror(errno)); |
---|
587 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
588 | stderr_bytes += strlen(buf); |
---|
589 | quit_pending = 1; |
---|
590 | return; |
---|
591 | } |
---|
592 | packet_process_incoming(buf, len); |
---|
593 | } |
---|
594 | |
---|
595 | /* Read input from stdin. */ |
---|
596 | if (FD_ISSET(fileno(stdin), readset)) |
---|
597 | { |
---|
598 | /* Read as much as possible. */ |
---|
599 | len = read(fileno(stdin), buf, sizeof(buf)); |
---|
600 | if (len <= 0) |
---|
601 | { |
---|
602 | /* Received EOF or error. They are treated similarly, |
---|
603 | except that an error message is printed if it was |
---|
604 | an error condition. */ |
---|
605 | if (len < 0) |
---|
606 | { |
---|
607 | sprintf(buf, "read: %.100s\r\n", strerror(errno)); |
---|
608 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
609 | stderr_bytes += strlen(buf); |
---|
610 | } |
---|
611 | /* Mark that we have seen EOF. */ |
---|
612 | stdin_eof = 1; |
---|
613 | /* Send an EOF message to the server unless there is data |
---|
614 | in the buffer. If there is data in the buffer, no message |
---|
615 | will be sent now. Code elsewhere will send the EOF |
---|
616 | when the buffer becomes empty if stdin_eof is set. */ |
---|
617 | if (buffer_len(&stdin_buffer) == 0) |
---|
618 | { |
---|
619 | packet_start(SSH_CMSG_EOF); |
---|
620 | packet_send(); |
---|
621 | } |
---|
622 | } |
---|
623 | else |
---|
624 | if (escape_char == -1) |
---|
625 | { |
---|
626 | /* Normal successful read, and no escape character. Just |
---|
627 | append the data to buffer. */ |
---|
628 | buffer_append(&stdin_buffer, buf, len); |
---|
629 | stdin_bytes += len; |
---|
630 | } |
---|
631 | else |
---|
632 | { |
---|
633 | /* Normal, successful read. But we have an escape character |
---|
634 | and have to process the characters one by one. */ |
---|
635 | unsigned int i; |
---|
636 | for (i = 0; i < len; i++) |
---|
637 | { |
---|
638 | unsigned char ch; |
---|
639 | /* Get one character at a time. */ |
---|
640 | ch = buf[i]; |
---|
641 | |
---|
642 | /* Check if we have a pending escape character. */ |
---|
643 | if (escape_pending) |
---|
644 | { |
---|
645 | /* We have previously seen an escape character. */ |
---|
646 | /* Clear the flag now. */ |
---|
647 | escape_pending = 0; |
---|
648 | /* Process the escaped character. */ |
---|
649 | switch (ch) |
---|
650 | { |
---|
651 | case '.': |
---|
652 | /* Terminate the connection. */ |
---|
653 | sprintf(buf, "%c.\r\n", escape_char); |
---|
654 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
655 | stderr_bytes += strlen(buf); |
---|
656 | quit_pending = 1; |
---|
657 | return; |
---|
658 | |
---|
659 | case 'Z' - 64: |
---|
660 | /* Suspend the program. */ |
---|
661 | /* Print a message to that effect to the user. */ |
---|
662 | sprintf(buf, "%c^Z\r\n", escape_char); |
---|
663 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
664 | stderr_bytes += strlen(buf); |
---|
665 | |
---|
666 | /* Restore terminal modes and suspend. */ |
---|
667 | client_suspend_self(); |
---|
668 | |
---|
669 | /* We have been continued. */ |
---|
670 | continue; |
---|
671 | |
---|
672 | case '&': |
---|
673 | /* Detach the program (continue to serve connections, |
---|
674 | but put in background and no more new |
---|
675 | connections). */ |
---|
676 | if (!stdin_eof) |
---|
677 | { |
---|
678 | /* Sending SSH_CMSG_EOF alone does not always |
---|
679 | appear to be enough. So we try to send an |
---|
680 | EOF character first. */ |
---|
681 | packet_start(SSH_CMSG_STDIN_DATA); |
---|
682 | packet_put_string("\004", 1); |
---|
683 | packet_send(); |
---|
684 | /* Close stdin. */ |
---|
685 | stdin_eof = 1; |
---|
686 | if (buffer_len(&stdin_buffer) == 0) |
---|
687 | { |
---|
688 | packet_start(SSH_CMSG_EOF); |
---|
689 | packet_send(); |
---|
690 | } |
---|
691 | } |
---|
692 | /* Restore tty modes. */ |
---|
693 | leave_raw_mode(); |
---|
694 | |
---|
695 | /* Stop listening for new connections. */ |
---|
696 | channel_stop_listening(); |
---|
697 | |
---|
698 | printf("%c& [backgrounded]\n", escape_char); |
---|
699 | |
---|
700 | /* Fork into background. */ |
---|
701 | pid = fork(); |
---|
702 | if (pid < 0) |
---|
703 | { |
---|
704 | error("fork: %.100s", strerror(errno)); |
---|
705 | continue; |
---|
706 | } |
---|
707 | if (pid != 0) |
---|
708 | { /* This is the parent. */ |
---|
709 | /* The parent just exits. */ |
---|
710 | exit(0); |
---|
711 | } |
---|
712 | |
---|
713 | /* The child continues serving connections. */ |
---|
714 | continue; |
---|
715 | |
---|
716 | case '?': |
---|
717 | sprintf(buf, "%c?\r\n\ |
---|
718 | Supported escape sequences:\r\n\ |
---|
719 | ~. - terminate connection\r\n\ |
---|
720 | ~^Z - suspend ssh\r\n\ |
---|
721 | ~# - list forwarded connections\r\n\ |
---|
722 | ~& - background ssh (when waiting for connections to terminate)\r\n\ |
---|
723 | ~? - this message\r\n\ |
---|
724 | ~~ - send the escape character by typing it twice\r\n\ |
---|
725 | (Note that escapes are only recognized immediately after newline.)\r\n", |
---|
726 | escape_char); |
---|
727 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
728 | continue; |
---|
729 | |
---|
730 | case '#': |
---|
731 | sprintf(buf, "%c#\r\n", escape_char); |
---|
732 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
733 | s = channel_open_message(); |
---|
734 | buffer_append(&stderr_buffer, s, strlen(s)); |
---|
735 | xfree(s); |
---|
736 | continue; |
---|
737 | |
---|
738 | default: |
---|
739 | if (ch != escape_char) |
---|
740 | { |
---|
741 | /* Escape character followed by non-special |
---|
742 | character. Append both to the input |
---|
743 | buffer. */ |
---|
744 | buf[0] = escape_char; |
---|
745 | buf[1] = ch; |
---|
746 | buffer_append(&stdin_buffer, buf, 2); |
---|
747 | stdin_bytes += 2; |
---|
748 | continue; |
---|
749 | } |
---|
750 | /* Note that escape character typed twice falls through |
---|
751 | here; the latter gets processed as a normal |
---|
752 | character below. */ |
---|
753 | break; |
---|
754 | } |
---|
755 | } |
---|
756 | else |
---|
757 | { |
---|
758 | /* The previous character was not an escape char. |
---|
759 | Check if this is an escape. */ |
---|
760 | if (last_was_cr && ch == escape_char) |
---|
761 | { |
---|
762 | /* It is. Set the flag and continue to next |
---|
763 | character. */ |
---|
764 | escape_pending = 1; |
---|
765 | continue; |
---|
766 | } |
---|
767 | } |
---|
768 | |
---|
769 | /* Normal character. Record whether it was a newline, |
---|
770 | and append it to the buffer. */ |
---|
771 | last_was_cr = (ch == '\r' || ch == '\n'); |
---|
772 | buf[0] = ch; |
---|
773 | buffer_append(&stdin_buffer, buf, 1); |
---|
774 | stdin_bytes += 1; |
---|
775 | continue; |
---|
776 | } |
---|
777 | } |
---|
778 | } |
---|
779 | } |
---|
780 | |
---|
781 | void client_process_output(fd_set *writeset) |
---|
782 | { |
---|
783 | int len; |
---|
784 | char buf[100]; |
---|
785 | |
---|
786 | /* Write buffered output to stdout. */ |
---|
787 | if (FD_ISSET(fileno(stdout), writeset)) |
---|
788 | { |
---|
789 | /* Write as much data as possible. */ |
---|
790 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), |
---|
791 | buffer_len(&stdout_buffer)); |
---|
792 | if (len <= 0) |
---|
793 | { |
---|
794 | if (errno == EAGAIN || errno == EWOULDBLOCK) |
---|
795 | len = 0; |
---|
796 | else |
---|
797 | { |
---|
798 | /* An error or EOF was encountered. Put an error message |
---|
799 | to stderr buffer. */ |
---|
800 | sprintf(buf, "write stdout: %.50s\r\n", strerror(errno)); |
---|
801 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
802 | stderr_bytes += strlen(buf); |
---|
803 | quit_pending = 1; |
---|
804 | return; |
---|
805 | } |
---|
806 | } |
---|
807 | /* Consume printed data from the buffer. */ |
---|
808 | buffer_consume(&stdout_buffer, len); |
---|
809 | } |
---|
810 | |
---|
811 | /* Write buffered output to stderr. */ |
---|
812 | if (FD_ISSET(fileno(stderr), writeset)) |
---|
813 | { |
---|
814 | /* Write as much data as possible. */ |
---|
815 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), |
---|
816 | buffer_len(&stderr_buffer)); |
---|
817 | if (len <= 0) |
---|
818 | if (errno == EAGAIN || errno == EWOULDBLOCK) |
---|
819 | len = 0; |
---|
820 | else |
---|
821 | { |
---|
822 | /* EOF or error, but can't even print error message. */ |
---|
823 | quit_pending = 1; |
---|
824 | return; |
---|
825 | } |
---|
826 | /* Consume printed characters from the buffer. */ |
---|
827 | buffer_consume(&stderr_buffer, len); |
---|
828 | } |
---|
829 | } |
---|
830 | |
---|
831 | /* Implements the interactive session with the server. This is called |
---|
832 | after the user has been authenticated, and a command has been |
---|
833 | started on the remote host. If escape_char != -1, it is the character |
---|
834 | used as an escape character for terminating or suspending the |
---|
835 | session. */ |
---|
836 | |
---|
837 | int client_loop(int have_pty, int escape_char_arg) |
---|
838 | { |
---|
839 | double start_time, total_time; |
---|
840 | int len; |
---|
841 | char buf[100]; |
---|
842 | |
---|
843 | debug("Entering interactive session."); |
---|
844 | |
---|
845 | start_time = get_current_time(); |
---|
846 | |
---|
847 | /* Initialize variables. */ |
---|
848 | escape_pending = 0; |
---|
849 | last_was_cr = 1; |
---|
850 | exit_status = -1; |
---|
851 | stdin_eof = 0; |
---|
852 | buffer_high = 64 * 1024; |
---|
853 | connection_in = packet_get_connection_in(); |
---|
854 | connection_out = packet_get_connection_out(); |
---|
855 | max_fd = connection_in; |
---|
856 | if (connection_out > max_fd) |
---|
857 | max_fd = connection_out; |
---|
858 | stdin_bytes = 0; |
---|
859 | stdout_bytes = 0; |
---|
860 | stderr_bytes = 0; |
---|
861 | quit_pending = 0; |
---|
862 | escape_char = escape_char_arg; |
---|
863 | |
---|
864 | /* Initialize buffers. */ |
---|
865 | buffer_init(&stdin_buffer); |
---|
866 | buffer_init(&stdout_buffer); |
---|
867 | buffer_init(&stderr_buffer); |
---|
868 | |
---|
869 | /* Set signal handlers to restore non-blocking mode. */ |
---|
870 | signal(SIGINT, signal_handler); |
---|
871 | signal(SIGQUIT, signal_handler); |
---|
872 | signal(SIGTERM, signal_handler); |
---|
873 | signal(SIGPIPE, SIG_IGN); |
---|
874 | #ifdef SIGWINCH |
---|
875 | if (have_pty) |
---|
876 | signal(SIGWINCH, window_change_handler); |
---|
877 | #endif /* SIGWINCH */ |
---|
878 | |
---|
879 | /* Enter raw mode if have a pseudo terminal. */ |
---|
880 | if (have_pty) |
---|
881 | enter_raw_mode(); |
---|
882 | |
---|
883 | /* Check if we should immediately send of on stdin. */ |
---|
884 | client_check_initial_eof_on_stdin(); |
---|
885 | |
---|
886 | /* Main loop of the client for the interactive session mode. */ |
---|
887 | while (!quit_pending) |
---|
888 | { |
---|
889 | fd_set readset, writeset; |
---|
890 | |
---|
891 | /* Precess buffered packets sent by the server. */ |
---|
892 | client_process_buffered_input_packets(); |
---|
893 | |
---|
894 | /* Make packets of buffered stdin data, and buffer them for sending |
---|
895 | to the server. */ |
---|
896 | client_make_packets_from_stdin_data(); |
---|
897 | |
---|
898 | /* Make packets from buffered channel data, and buffer them for sending |
---|
899 | to the server. */ |
---|
900 | if (packet_not_very_much_data_to_write()) |
---|
901 | channel_output_poll(); |
---|
902 | |
---|
903 | /* Check if the window size has changed, and buffer a message about |
---|
904 | it to the server if so. */ |
---|
905 | client_check_window_change(); |
---|
906 | |
---|
907 | if (quit_pending) |
---|
908 | break; |
---|
909 | |
---|
910 | /* Wait until we have something to do (something becomes available |
---|
911 | on one of the descriptors). */ |
---|
912 | client_wait_until_can_do_something(&readset, &writeset); |
---|
913 | |
---|
914 | if (quit_pending) |
---|
915 | break; |
---|
916 | |
---|
917 | /* Do channel operations. */ |
---|
918 | channel_after_select(&readset, &writeset); |
---|
919 | |
---|
920 | /* Process input from the connection and from stdin. Buffer any data |
---|
921 | that is available. */ |
---|
922 | client_process_input(&readset); |
---|
923 | |
---|
924 | /* Process output to stdout and stderr. Output to the connection |
---|
925 | is processed elsewhere (above). */ |
---|
926 | client_process_output(&writeset); |
---|
927 | |
---|
928 | /* Send as much buffered packet data as possible to the sender. */ |
---|
929 | if (FD_ISSET(connection_out, &writeset)) |
---|
930 | packet_write_poll(); |
---|
931 | } |
---|
932 | |
---|
933 | /* Terminate the session. */ |
---|
934 | |
---|
935 | #ifdef SIGWINCH |
---|
936 | /* Stop watching for window change. */ |
---|
937 | if (have_pty) |
---|
938 | signal(SIGWINCH, SIG_DFL); |
---|
939 | #endif /* SIGWINCH */ |
---|
940 | |
---|
941 | /* Stop listening for connections. */ |
---|
942 | channel_stop_listening(); |
---|
943 | |
---|
944 | /* In interactive mode (with pseudo tty) display a message indicating that |
---|
945 | the connection has been closed. */ |
---|
946 | if (have_pty && !quiet_flag) |
---|
947 | { |
---|
948 | sprintf(buf, "Connection to %.64s closed.\r\n", host); |
---|
949 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
---|
950 | stderr_bytes += strlen(buf); |
---|
951 | } |
---|
952 | |
---|
953 | /* Output any buffered data for stdout. */ |
---|
954 | while (buffer_len(&stdout_buffer) > 0) |
---|
955 | { |
---|
956 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), |
---|
957 | buffer_len(&stdout_buffer)); |
---|
958 | if (len <= 0) |
---|
959 | { |
---|
960 | error("Write failed flushing stdout buffer."); |
---|
961 | break; |
---|
962 | } |
---|
963 | buffer_consume(&stdout_buffer, len); |
---|
964 | } |
---|
965 | |
---|
966 | /* Output any buffered data for stderr. */ |
---|
967 | while (buffer_len(&stderr_buffer) > 0) |
---|
968 | { |
---|
969 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), |
---|
970 | buffer_len(&stderr_buffer)); |
---|
971 | if (len <= 0) |
---|
972 | { |
---|
973 | error("Write failed flushing stderr buffer."); |
---|
974 | break; |
---|
975 | } |
---|
976 | buffer_consume(&stderr_buffer, len); |
---|
977 | } |
---|
978 | |
---|
979 | /* Leave raw mode. */ |
---|
980 | if (have_pty) |
---|
981 | leave_raw_mode(); |
---|
982 | |
---|
983 | /* Clear and free any buffers. */ |
---|
984 | memset(buf, 0, sizeof(buf)); |
---|
985 | buffer_free(&stdin_buffer); |
---|
986 | buffer_free(&stdout_buffer); |
---|
987 | buffer_free(&stderr_buffer); |
---|
988 | |
---|
989 | /* Report bytes transferred, and transfer rates. */ |
---|
990 | total_time = get_current_time() - start_time; |
---|
991 | debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", |
---|
992 | stdin_bytes, stdout_bytes, stderr_bytes, total_time); |
---|
993 | if (total_time > 0) |
---|
994 | debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", |
---|
995 | stdin_bytes / total_time, stdout_bytes / total_time, |
---|
996 | stderr_bytes / total_time); |
---|
997 | |
---|
998 | /* Return the exit status of the program. */ |
---|
999 | debug("Exit status %d", exit_status); |
---|
1000 | return exit_status; |
---|
1001 | } |
---|