Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
| 5 | * Created: Sun Sep 10 00:30:37 1995 ylo |
| 6 | * Server main loop for handling the interactive session. |
| 7 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 8 | |
| 9 | #include "includes.h" |
| 10 | #include "xmalloc.h" |
| 11 | #include "ssh.h" |
| 12 | #include "packet.h" |
| 13 | #include "buffer.h" |
| 14 | #include "servconf.h" |
| 15 | #include "pty.h" |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 16 | #include "channels.h" |
| 17 | |
| 18 | #include "compat.h" |
| 19 | #include "dispatch.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 20 | |
| 21 | static Buffer stdin_buffer; /* Buffer for stdin data. */ |
| 22 | static Buffer stdout_buffer; /* Buffer for stdout data. */ |
| 23 | static Buffer stderr_buffer; /* Buffer for stderr data. */ |
| 24 | static int fdin; /* Descriptor for stdin (for writing) */ |
| 25 | static int fdout; /* Descriptor for stdout (for reading); |
| 26 | May be same number as fdin. */ |
| 27 | static int fderr; /* Descriptor for stderr. May be -1. */ |
| 28 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ |
| 29 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ |
| 30 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ |
| 31 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ |
| 32 | static int stdin_eof = 0; /* EOF message received from client. */ |
| 33 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ |
| 34 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ |
| 35 | static int connection_in; /* Connection to client (input). */ |
| 36 | static int connection_out; /* Connection to client (output). */ |
| 37 | static unsigned int buffer_high;/* "Soft" max buffer size. */ |
| 38 | static int max_fd; /* Max file descriptor number for select(). */ |
| 39 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 40 | /* |
| 41 | * This SIGCHLD kludge is used to detect when the child exits. The server |
| 42 | * will exit after that, as soon as forwarded connections have terminated. |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 43 | * |
| 44 | * After SIGCHLD child_has_selected is set to 1 after the first pass |
| 45 | * through the wait_until_can_do_something() select(). This ensures |
| 46 | * that the child's output gets a chance to drain before it is yanked. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 47 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 48 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 49 | static int child_pid; /* Pid of the child. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 50 | static volatile int child_terminated; /* The child has terminated. */ |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 51 | static volatile int child_has_selected; /* Child has had chance to drain. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 52 | static volatile int child_wait_status; /* Status from wait(). */ |
| 53 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 54 | void server_init_dispatch(void); |
| 55 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 56 | void |
| 57 | sigchld_handler(int sig) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 58 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 59 | int save_errno = errno; |
| 60 | int wait_pid; |
| 61 | debug("Received SIGCHLD."); |
| 62 | wait_pid = wait((int *) &child_wait_status); |
| 63 | if (wait_pid != -1) { |
| 64 | if (wait_pid != child_pid) |
| 65 | error("Strange, got SIGCHLD and wait returned pid %d but child is %d", |
| 66 | wait_pid, child_pid); |
| 67 | if (WIFEXITED(child_wait_status) || |
| 68 | WIFSIGNALED(child_wait_status)) |
| 69 | child_terminated = 1; |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 70 | child_has_selected = 0; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 71 | } |
| 72 | signal(SIGCHLD, sigchld_handler); |
| 73 | errno = save_errno; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 74 | } |
| 75 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 76 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 77 | * Make packets from buffered stderr data, and buffer it for sending |
| 78 | * to the client. |
| 79 | */ |
| 80 | void |
| 81 | make_packets_from_stderr_data() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 82 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 83 | int len; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 84 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 85 | /* Send buffered stderr data to the client. */ |
| 86 | while (buffer_len(&stderr_buffer) > 0 && |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 87 | packet_not_very_much_data_to_write()) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 88 | len = buffer_len(&stderr_buffer); |
| 89 | if (packet_is_interactive()) { |
| 90 | if (len > 512) |
| 91 | len = 512; |
| 92 | } else { |
| 93 | /* Keep the packets at reasonable size. */ |
| 94 | if (len > packet_get_maxsize()) |
| 95 | len = packet_get_maxsize(); |
| 96 | } |
| 97 | packet_start(SSH_SMSG_STDERR_DATA); |
| 98 | packet_put_string(buffer_ptr(&stderr_buffer), len); |
| 99 | packet_send(); |
| 100 | buffer_consume(&stderr_buffer, len); |
| 101 | stderr_bytes += len; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 102 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 103 | } |
| 104 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 105 | /* |
| 106 | * Make packets from buffered stdout data, and buffer it for sending to the |
| 107 | * client. |
| 108 | */ |
| 109 | void |
| 110 | make_packets_from_stdout_data() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 111 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 112 | int len; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 113 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 114 | /* Send buffered stdout data to the client. */ |
| 115 | while (buffer_len(&stdout_buffer) > 0 && |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 116 | packet_not_very_much_data_to_write()) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 117 | len = buffer_len(&stdout_buffer); |
| 118 | if (packet_is_interactive()) { |
| 119 | if (len > 512) |
| 120 | len = 512; |
| 121 | } else { |
| 122 | /* Keep the packets at reasonable size. */ |
| 123 | if (len > packet_get_maxsize()) |
| 124 | len = packet_get_maxsize(); |
| 125 | } |
| 126 | packet_start(SSH_SMSG_STDOUT_DATA); |
| 127 | packet_put_string(buffer_ptr(&stdout_buffer), len); |
| 128 | packet_send(); |
| 129 | buffer_consume(&stdout_buffer, len); |
| 130 | stdout_bytes += len; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 131 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 132 | } |
| 133 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 134 | /* |
| 135 | * Sleep in select() until we can do something. This will initialize the |
| 136 | * select masks. Upon return, the masks will indicate which descriptors |
| 137 | * have data or can accept data. Optionally, a maximum time can be specified |
| 138 | * for the duration of the wait (0 = infinite). |
| 139 | */ |
| 140 | void |
| 141 | wait_until_can_do_something(fd_set * readset, fd_set * writeset, |
| 142 | unsigned int max_time_milliseconds) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 143 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 144 | struct timeval tv, *tvp; |
| 145 | int ret; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 146 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 147 | /* When select fails we restart from here. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 148 | retry_select: |
| 149 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 150 | /* Initialize select() masks. */ |
| 151 | FD_ZERO(readset); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 152 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 153 | /* |
| 154 | * Read packets from the client unless we have too much buffered |
| 155 | * stdin or channel data. |
| 156 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 157 | if (buffer_len(&stdin_buffer) < 4096 && |
| 158 | channel_not_very_much_buffered_data()) |
| 159 | FD_SET(connection_in, readset); |
| 160 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 161 | /* |
| 162 | * If there is not too much data already buffered going to the |
| 163 | * client, try to get some more data from the program. |
| 164 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 165 | if (packet_not_very_much_data_to_write()) { |
| 166 | if (!fdout_eof) |
| 167 | FD_SET(fdout, readset); |
| 168 | if (!fderr_eof) |
| 169 | FD_SET(fderr, readset); |
| 170 | } |
| 171 | FD_ZERO(writeset); |
| 172 | |
| 173 | /* Set masks for channel descriptors. */ |
| 174 | channel_prepare_select(readset, writeset); |
| 175 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 176 | /* |
| 177 | * If we have buffered packet data going to the client, mark that |
| 178 | * descriptor. |
| 179 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 180 | if (packet_have_data_to_write()) |
| 181 | FD_SET(connection_out, writeset); |
| 182 | |
| 183 | /* If we have buffered data, try to write some of that data to the |
| 184 | program. */ |
| 185 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) |
| 186 | FD_SET(fdin, writeset); |
| 187 | |
| 188 | /* Update the maximum descriptor number if appropriate. */ |
| 189 | if (channel_max_fd() > max_fd) |
| 190 | max_fd = channel_max_fd(); |
| 191 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 192 | /* |
| 193 | * If child has terminated and there is enough buffer space to read |
| 194 | * from it, then read as much as is available and exit. |
| 195 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 196 | if (child_terminated && packet_not_very_much_data_to_write()) |
| 197 | if (max_time_milliseconds == 0) |
| 198 | max_time_milliseconds = 100; |
| 199 | |
| 200 | if (max_time_milliseconds == 0) |
| 201 | tvp = NULL; |
| 202 | else { |
| 203 | tv.tv_sec = max_time_milliseconds / 1000; |
| 204 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); |
| 205 | tvp = &tv; |
| 206 | } |
| 207 | |
| 208 | /* Wait for something to happen, or the timeout to expire. */ |
| 209 | ret = select(max_fd + 1, readset, writeset, NULL, tvp); |
| 210 | |
| 211 | if (ret < 0) { |
| 212 | if (errno != EINTR) |
| 213 | error("select: %.100s", strerror(errno)); |
| 214 | else |
| 215 | goto retry_select; |
| 216 | } |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 217 | |
| 218 | if (child_terminated) |
| 219 | child_has_selected = 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 220 | } |
| 221 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 222 | /* |
| 223 | * Processes input from the client and the program. Input data is stored |
| 224 | * in buffers and processed later. |
| 225 | */ |
| 226 | void |
| 227 | process_input(fd_set * readset) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 228 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 229 | int len; |
| 230 | char buf[16384]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 231 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 232 | /* Read and buffer any input data from the client. */ |
| 233 | if (FD_ISSET(connection_in, readset)) { |
| 234 | len = read(connection_in, buf, sizeof(buf)); |
| 235 | if (len == 0) { |
| 236 | verbose("Connection closed by remote host."); |
| 237 | fatal_cleanup(); |
| 238 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 239 | /* |
| 240 | * There is a kernel bug on Solaris that causes select to |
| 241 | * sometimes wake up even though there is no data available. |
| 242 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 243 | if (len < 0 && errno == EAGAIN) |
| 244 | len = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 245 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 246 | if (len < 0) { |
| 247 | verbose("Read error from remote host: %.100s", strerror(errno)); |
| 248 | fatal_cleanup(); |
| 249 | } |
| 250 | /* Buffer any received data. */ |
| 251 | packet_process_incoming(buf, len); |
| 252 | } |
| 253 | /* Read and buffer any available stdout data from the program. */ |
| 254 | if (!fdout_eof && FD_ISSET(fdout, readset)) { |
| 255 | len = read(fdout, buf, sizeof(buf)); |
| 256 | if (len <= 0) |
| 257 | fdout_eof = 1; |
| 258 | else { |
| 259 | buffer_append(&stdout_buffer, buf, len); |
| 260 | fdout_bytes += len; |
| 261 | } |
| 262 | } |
| 263 | /* Read and buffer any available stderr data from the program. */ |
| 264 | if (!fderr_eof && FD_ISSET(fderr, readset)) { |
| 265 | len = read(fderr, buf, sizeof(buf)); |
| 266 | if (len <= 0) |
| 267 | fderr_eof = 1; |
| 268 | else |
| 269 | buffer_append(&stderr_buffer, buf, len); |
| 270 | } |
| 271 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 272 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 273 | /* |
| 274 | * Sends data from internal buffers to client program stdin. |
| 275 | */ |
| 276 | void |
| 277 | process_output(fd_set * writeset) |
| 278 | { |
| 279 | int len; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 280 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 281 | /* Write buffered data to program stdin. */ |
| 282 | if (fdin != -1 && FD_ISSET(fdin, writeset)) { |
| 283 | len = write(fdin, buffer_ptr(&stdin_buffer), |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 284 | buffer_len(&stdin_buffer)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 285 | if (len <= 0) { |
| 286 | #ifdef USE_PIPES |
| 287 | close(fdin); |
| 288 | #else |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 289 | if (fdin != fdout) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 290 | close(fdin); |
| 291 | else |
| 292 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ |
| 293 | #endif |
| 294 | fdin = -1; |
| 295 | } else { |
| 296 | /* Successful write. Consume the data from the buffer. */ |
| 297 | buffer_consume(&stdin_buffer, len); |
| 298 | /* Update the count of bytes written to the program. */ |
| 299 | stdin_bytes += len; |
| 300 | } |
| 301 | } |
| 302 | /* Send any buffered packet data to the client. */ |
| 303 | if (FD_ISSET(connection_out, writeset)) |
| 304 | packet_write_poll(); |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * Wait until all buffered output has been sent to the client. |
| 309 | * This is used when the program terminates. |
| 310 | */ |
| 311 | void |
| 312 | drain_output() |
| 313 | { |
| 314 | /* Send any buffered stdout data to the client. */ |
| 315 | if (buffer_len(&stdout_buffer) > 0) { |
| 316 | packet_start(SSH_SMSG_STDOUT_DATA); |
| 317 | packet_put_string(buffer_ptr(&stdout_buffer), |
| 318 | buffer_len(&stdout_buffer)); |
| 319 | packet_send(); |
| 320 | /* Update the count of sent bytes. */ |
| 321 | stdout_bytes += buffer_len(&stdout_buffer); |
| 322 | } |
| 323 | /* Send any buffered stderr data to the client. */ |
| 324 | if (buffer_len(&stderr_buffer) > 0) { |
| 325 | packet_start(SSH_SMSG_STDERR_DATA); |
| 326 | packet_put_string(buffer_ptr(&stderr_buffer), |
| 327 | buffer_len(&stderr_buffer)); |
| 328 | packet_send(); |
| 329 | /* Update the count of sent bytes. */ |
| 330 | stderr_bytes += buffer_len(&stderr_buffer); |
| 331 | } |
| 332 | /* Wait until all buffered data has been written to the client. */ |
| 333 | packet_write_wait(); |
| 334 | } |
| 335 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 336 | void |
| 337 | process_buffered_input_packets() |
| 338 | { |
| 339 | dispatch_run(DISPATCH_NONBLOCK, NULL); |
| 340 | } |
| 341 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 342 | /* |
| 343 | * Performs the interactive session. This handles data transmission between |
| 344 | * the client and the program. Note that the notion of stdin, stdout, and |
| 345 | * stderr in this function is sort of reversed: this function writes to |
| 346 | * stdin (of the child program), and reads from stdout and stderr (of the |
| 347 | * child program). |
| 348 | */ |
| 349 | void |
| 350 | server_loop(int pid, int fdin_arg, int fdout_arg, int fderr_arg) |
| 351 | { |
| 352 | int wait_status, wait_pid; /* Status and pid returned by wait(). */ |
| 353 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
| 354 | unsigned int max_time_milliseconds; |
| 355 | unsigned int previous_stdout_buffer_bytes; |
| 356 | unsigned int stdout_buffer_bytes; |
| 357 | int type; |
| 358 | |
| 359 | debug("Entering interactive session."); |
| 360 | |
| 361 | /* Initialize the SIGCHLD kludge. */ |
| 362 | child_pid = pid; |
| 363 | child_terminated = 0; |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 364 | child_has_selected = 0; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 365 | signal(SIGCHLD, sigchld_handler); |
| 366 | |
| 367 | /* Initialize our global variables. */ |
| 368 | fdin = fdin_arg; |
| 369 | fdout = fdout_arg; |
| 370 | fderr = fderr_arg; |
| 371 | connection_in = packet_get_connection_in(); |
| 372 | connection_out = packet_get_connection_out(); |
| 373 | |
| 374 | previous_stdout_buffer_bytes = 0; |
| 375 | |
| 376 | /* Set approximate I/O buffer size. */ |
| 377 | if (packet_is_interactive()) |
| 378 | buffer_high = 4096; |
| 379 | else |
| 380 | buffer_high = 64 * 1024; |
| 381 | |
| 382 | /* Initialize max_fd to the maximum of the known file descriptors. */ |
| 383 | max_fd = fdin; |
| 384 | if (fdout > max_fd) |
| 385 | max_fd = fdout; |
| 386 | if (fderr != -1 && fderr > max_fd) |
| 387 | max_fd = fderr; |
| 388 | if (connection_in > max_fd) |
| 389 | max_fd = connection_in; |
| 390 | if (connection_out > max_fd) |
| 391 | max_fd = connection_out; |
| 392 | |
| 393 | /* Initialize Initialize buffers. */ |
| 394 | buffer_init(&stdin_buffer); |
| 395 | buffer_init(&stdout_buffer); |
| 396 | buffer_init(&stderr_buffer); |
| 397 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 398 | /* |
| 399 | * If we have no separate fderr (which is the case when we have a pty |
| 400 | * - there we cannot make difference between data sent to stdout and |
| 401 | * stderr), indicate that we have seen an EOF from stderr. This way |
| 402 | * we don\'t need to check the descriptor everywhere. |
| 403 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 404 | if (fderr == -1) |
| 405 | fderr_eof = 1; |
| 406 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 407 | server_init_dispatch(); |
| 408 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 409 | /* Main loop of the server for the interactive session mode. */ |
| 410 | for (;;) { |
| 411 | fd_set readset, writeset; |
| 412 | |
| 413 | /* Process buffered packets from the client. */ |
| 414 | process_buffered_input_packets(); |
| 415 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 416 | /* |
| 417 | * If we have received eof, and there is no more pending |
| 418 | * input data, cause a real eof by closing fdin. |
| 419 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 420 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
| 421 | #ifdef USE_PIPES |
| 422 | close(fdin); |
| 423 | #else |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 424 | if (fdin != fdout) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 425 | close(fdin); |
| 426 | else |
| 427 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ |
| 428 | #endif |
| 429 | fdin = -1; |
| 430 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 431 | /* Make packets from buffered stderr data to send to the client. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 432 | make_packets_from_stderr_data(); |
| 433 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 434 | /* |
| 435 | * Make packets from buffered stdout data to send to the |
| 436 | * client. If there is very little to send, this arranges to |
| 437 | * not send them now, but to wait a short while to see if we |
| 438 | * are getting more data. This is necessary, as some systems |
| 439 | * wake up readers from a pty after each separate character. |
| 440 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 441 | max_time_milliseconds = 0; |
| 442 | stdout_buffer_bytes = buffer_len(&stdout_buffer); |
| 443 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && |
| 444 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { |
| 445 | /* try again after a while */ |
| 446 | max_time_milliseconds = 10; |
| 447 | } else { |
| 448 | /* Send it now. */ |
| 449 | make_packets_from_stdout_data(); |
| 450 | } |
| 451 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); |
| 452 | |
| 453 | /* Send channel data to the client. */ |
| 454 | if (packet_not_very_much_data_to_write()) |
| 455 | channel_output_poll(); |
| 456 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 457 | /* |
| 458 | * Bail out of the loop if the program has closed its output |
| 459 | * descriptors, and we have no more data to send to the |
| 460 | * client, and there is no pending buffered data. |
| 461 | */ |
Damien Miller | b284b54 | 2000-01-17 20:55:18 +1100 | [diff] [blame] | 462 | if (((fdout_eof && fderr_eof) || |
| 463 | (child_terminated && child_has_selected)) && |
| 464 | !packet_have_data_to_write() && |
| 465 | (buffer_len(&stdout_buffer) == 0) && |
| 466 | (buffer_len(&stderr_buffer) == 0)) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 467 | if (!channel_still_open()) |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 468 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 469 | if (!waiting_termination) { |
| 470 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; |
| 471 | char *cp; |
| 472 | waiting_termination = 1; |
| 473 | buffer_append(&stderr_buffer, s, strlen(s)); |
| 474 | |
| 475 | /* Display list of open channels. */ |
| 476 | cp = channel_open_message(); |
| 477 | buffer_append(&stderr_buffer, cp, strlen(cp)); |
| 478 | xfree(cp); |
| 479 | } |
| 480 | } |
| 481 | /* Sleep in select() until we can do something. */ |
| 482 | wait_until_can_do_something(&readset, &writeset, |
| 483 | max_time_milliseconds); |
| 484 | |
| 485 | /* Process any channel events. */ |
| 486 | channel_after_select(&readset, &writeset); |
| 487 | |
| 488 | /* Process input from the client and from program stdout/stderr. */ |
| 489 | process_input(&readset); |
| 490 | |
| 491 | /* Process output to the client and to program stdin. */ |
| 492 | process_output(&writeset); |
| 493 | } |
| 494 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 495 | /* Cleanup and termination code. */ |
| 496 | |
| 497 | /* Wait until all output has been sent to the client. */ |
| 498 | drain_output(); |
| 499 | |
| 500 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
| 501 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); |
| 502 | |
| 503 | /* Free and clear the buffers. */ |
| 504 | buffer_free(&stdin_buffer); |
| 505 | buffer_free(&stdout_buffer); |
| 506 | buffer_free(&stderr_buffer); |
| 507 | |
| 508 | /* Close the file descriptors. */ |
| 509 | if (fdout != -1) |
| 510 | close(fdout); |
| 511 | fdout = -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 512 | fdout_eof = 1; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 513 | if (fderr != -1) |
| 514 | close(fderr); |
| 515 | fderr = -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 516 | fderr_eof = 1; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 517 | if (fdin != -1) |
| 518 | close(fdin); |
| 519 | fdin = -1; |
| 520 | |
| 521 | /* Stop listening for channels; this removes unix domain sockets. */ |
| 522 | channel_stop_listening(); |
| 523 | |
| 524 | /* Wait for the child to exit. Get its exit status. */ |
| 525 | wait_pid = wait(&wait_status); |
| 526 | if (wait_pid < 0) { |
| 527 | /* |
| 528 | * It is possible that the wait was handled by SIGCHLD |
| 529 | * handler. This may result in either: this call |
| 530 | * returning with EINTR, or: this call returning ECHILD. |
| 531 | */ |
| 532 | if (child_terminated) |
| 533 | wait_status = child_wait_status; |
| 534 | else |
| 535 | packet_disconnect("wait: %.100s", strerror(errno)); |
| 536 | } else { |
| 537 | /* Check if it matches the process we forked. */ |
| 538 | if (wait_pid != pid) |
| 539 | error("Strange, wait returned pid %d, expected %d", |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 540 | wait_pid, pid); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 541 | } |
| 542 | |
| 543 | /* We no longer want our SIGCHLD handler to be called. */ |
| 544 | signal(SIGCHLD, SIG_DFL); |
| 545 | |
| 546 | /* Check if it exited normally. */ |
| 547 | if (WIFEXITED(wait_status)) { |
| 548 | /* Yes, normal exit. Get exit status and send it to the client. */ |
| 549 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); |
| 550 | packet_start(SSH_SMSG_EXITSTATUS); |
| 551 | packet_put_int(WEXITSTATUS(wait_status)); |
| 552 | packet_send(); |
| 553 | packet_write_wait(); |
| 554 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 555 | /* |
| 556 | * Wait for exit confirmation. Note that there might be |
| 557 | * other packets coming before it; however, the program has |
| 558 | * already died so we just ignore them. The client is |
| 559 | * supposed to respond with the confirmation when it receives |
| 560 | * the exit status. |
| 561 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 562 | do { |
| 563 | int plen; |
| 564 | type = packet_read(&plen); |
| 565 | } |
| 566 | while (type != SSH_CMSG_EXIT_CONFIRMATION); |
| 567 | |
| 568 | debug("Received exit confirmation."); |
| 569 | return; |
| 570 | } |
| 571 | /* Check if the program terminated due to a signal. */ |
| 572 | if (WIFSIGNALED(wait_status)) |
| 573 | packet_disconnect("Command terminated on signal %d.", |
| 574 | WTERMSIG(wait_status)); |
| 575 | |
| 576 | /* Some weird exit cause. Just exit. */ |
| 577 | packet_disconnect("wait returned status %04x.", wait_status); |
| 578 | /* NOTREACHED */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 579 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 580 | |
| 581 | void |
| 582 | server_input_stdin_data(int type, int plen) |
| 583 | { |
| 584 | char *data; |
| 585 | unsigned int data_len; |
| 586 | |
| 587 | /* Stdin data from the client. Append it to the buffer. */ |
| 588 | /* Ignore any data if the client has closed stdin. */ |
| 589 | if (fdin == -1) |
| 590 | return; |
| 591 | data = packet_get_string(&data_len); |
| 592 | packet_integrity_check(plen, (4 + data_len), type); |
| 593 | buffer_append(&stdin_buffer, data, data_len); |
| 594 | memset(data, 0, data_len); |
| 595 | xfree(data); |
| 596 | } |
| 597 | |
| 598 | void |
| 599 | server_input_eof(int type, int plen) |
| 600 | { |
| 601 | /* |
| 602 | * Eof from the client. The stdin descriptor to the |
| 603 | * program will be closed when all buffered data has |
| 604 | * drained. |
| 605 | */ |
| 606 | debug("EOF received for stdin."); |
| 607 | packet_integrity_check(plen, 0, type); |
| 608 | stdin_eof = 1; |
| 609 | } |
| 610 | |
| 611 | void |
| 612 | server_input_window_size(int type, int plen) |
| 613 | { |
| 614 | int row = packet_get_int(); |
| 615 | int col = packet_get_int(); |
| 616 | int xpixel = packet_get_int(); |
| 617 | int ypixel = packet_get_int(); |
| 618 | |
| 619 | debug("Window change received."); |
| 620 | packet_integrity_check(plen, 4 * 4, type); |
| 621 | if (fdin != -1) |
| 622 | pty_change_window_size(fdin, row, col, xpixel, ypixel); |
| 623 | } |
| 624 | |
| 625 | void |
| 626 | server_init_dispatch_13() |
| 627 | { |
| 628 | debug("server_init_dispatch_13"); |
| 629 | dispatch_init(NULL); |
| 630 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); |
| 631 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); |
| 632 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); |
| 633 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); |
| 634 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); |
| 635 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); |
| 636 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); |
| 637 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); |
| 638 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); |
| 639 | } |
| 640 | void |
| 641 | server_init_dispatch_15() |
| 642 | { |
| 643 | server_init_dispatch_13(); |
| 644 | debug("server_init_dispatch_15"); |
| 645 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); |
| 646 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); |
| 647 | } |
| 648 | void |
| 649 | server_init_dispatch() |
| 650 | { |
| 651 | if (compat13) |
| 652 | server_init_dispatch_13(); |
| 653 | else |
| 654 | server_init_dispatch_15(); |
| 655 | } |