diff options
Diffstat (limited to 'serverloop.c')
| -rw-r--r-- | serverloop.c | 1112 |
1 files changed, 548 insertions, 564 deletions
diff --git a/serverloop.c b/serverloop.c index 9961170a..fc959bae 100644 --- a/serverloop.c +++ b/serverloop.c @@ -1,17 +1,10 @@ /* - -serverloop.c - -Author: Tatu Ylonen <ylo@cs.hut.fi> - -Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland - All rights reserved - -Created: Sun Sep 10 00:30:37 1995 ylo - -Server main loop for handling the interactive session. - -*/ + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * Created: Sun Sep 10 00:30:37 1995 ylo + * Server main loop for handling the interactive session. + */ #include "includes.h" #include "xmalloc.h" @@ -43,603 +36,594 @@ static int max_fd; /* Max file descriptor number for select(). */ /* This SIGCHLD kludge is used to detect when the child exits. The server will exit after that, as soon as forwarded connections have terminated. */ -static int child_pid; /* Pid of the child. */ +static int child_pid; /* Pid of the child. */ static volatile int child_terminated; /* The child has terminated. */ static volatile int child_wait_status; /* Status from wait(). */ -void sigchld_handler(int sig) +void +sigchld_handler(int sig) { - int save_errno = errno; - int wait_pid; - debug("Received SIGCHLD."); - wait_pid = wait((int *)&child_wait_status); - if (wait_pid != -1) - { - if (wait_pid != child_pid) - error("Strange, got SIGCHLD and wait returned pid %d but child is %d", - wait_pid, child_pid); - if (WIFEXITED(child_wait_status) || - WIFSIGNALED(child_wait_status)) - child_terminated = 1; - } - signal(SIGCHLD, sigchld_handler); - errno = save_errno; + int save_errno = errno; + int wait_pid; + debug("Received SIGCHLD."); + wait_pid = wait((int *) &child_wait_status); + if (wait_pid != -1) { + if (wait_pid != child_pid) + error("Strange, got SIGCHLD and wait returned pid %d but child is %d", + wait_pid, child_pid); + if (WIFEXITED(child_wait_status) || + WIFSIGNALED(child_wait_status)) + child_terminated = 1; + } + signal(SIGCHLD, sigchld_handler); + errno = save_errno; } -/* Process any buffered packets that have been received from the client. */ - -void process_buffered_input_packets() +/* + * Process any buffered packets that have been received from the client. + */ +void +process_buffered_input_packets() { - int type; - char *data; - unsigned int data_len; - int row, col, xpixel, ypixel; - int payload_len; - - /* Process buffered packets from the client. */ - while ((type = packet_read_poll(&payload_len)) != SSH_MSG_NONE) - { - switch (type) - { - case SSH_CMSG_STDIN_DATA: - /* Stdin data from the client. Append it to the buffer. */ - if (fdin == -1) - break; /* Ignore any data if the client has closed stdin. */ - data = packet_get_string(&data_len); - packet_integrity_check(payload_len, (4 + data_len), type); - buffer_append(&stdin_buffer, data, data_len); - memset(data, 0, data_len); - xfree(data); - break; - - case SSH_CMSG_EOF: - /* Eof from the client. The stdin descriptor to the program - will be closed when all buffered data has drained. */ - debug("EOF received for stdin."); - packet_integrity_check(payload_len, 0, type); - stdin_eof = 1; - break; - - case SSH_CMSG_WINDOW_SIZE: - debug("Window change received."); - packet_integrity_check(payload_len, 4*4, type); - row = packet_get_int(); - col = packet_get_int(); - xpixel = packet_get_int(); - ypixel = packet_get_int(); - if (fdin != -1) - pty_change_window_size(fdin, row, col, xpixel, ypixel); - break; - - case SSH_MSG_PORT_OPEN: - debug("Received port open request."); - channel_input_port_open(payload_len); - break; - - case SSH_MSG_CHANNEL_OPEN_CONFIRMATION: - debug("Received channel open confirmation."); - packet_integrity_check(payload_len, 4 + 4, type); - channel_input_open_confirmation(); - break; - - case SSH_MSG_CHANNEL_OPEN_FAILURE: - debug("Received channel open failure."); - packet_integrity_check(payload_len, 4, type); - channel_input_open_failure(); - break; - - case SSH_MSG_CHANNEL_DATA: - channel_input_data(payload_len); - break; - - case SSH_MSG_CHANNEL_CLOSE: - debug("Received channel close."); - packet_integrity_check(payload_len, 4, type); - channel_input_close(); - break; - - case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION: - debug("Received channel close confirmation."); - packet_integrity_check(payload_len, 4, type); - channel_input_close_confirmation(); - break; - - default: - /* In this phase, any unexpected messages cause a protocol - error. This is to ease debugging; also, since no - confirmations are sent messages, unprocessed unknown - messages could cause strange problems. Any compatible - protocol extensions must be negotiated before entering the - interactive session. */ - packet_disconnect("Protocol error during session: type %d", - type); + int type; + char *data; + unsigned int data_len; + int row, col, xpixel, ypixel; + int payload_len; + + /* Process buffered packets from the client. */ + while ((type = packet_read_poll(&payload_len)) != SSH_MSG_NONE) { + switch (type) { + case SSH_CMSG_STDIN_DATA: + /* Stdin data from the client. Append it to the buffer. */ + /* Ignore any data if the client has closed stdin. */ + if (fdin == -1) + break; + data = packet_get_string(&data_len); + packet_integrity_check(payload_len, (4 + data_len), type); + buffer_append(&stdin_buffer, data, data_len); + memset(data, 0, data_len); + xfree(data); + break; + + case SSH_CMSG_EOF: + /* Eof from the client. The stdin descriptor to + the program will be closed when all buffered + data has drained. */ + debug("EOF received for stdin."); + packet_integrity_check(payload_len, 0, type); + stdin_eof = 1; + break; + + case SSH_CMSG_WINDOW_SIZE: + debug("Window change received."); + packet_integrity_check(payload_len, 4 * 4, type); + row = packet_get_int(); + col = packet_get_int(); + xpixel = packet_get_int(); + ypixel = packet_get_int(); + if (fdin != -1) + pty_change_window_size(fdin, row, col, xpixel, ypixel); + break; + + case SSH_MSG_PORT_OPEN: + debug("Received port open request."); + channel_input_port_open(payload_len); + break; + + case SSH_MSG_CHANNEL_OPEN_CONFIRMATION: + debug("Received channel open confirmation."); + packet_integrity_check(payload_len, 4 + 4, type); + channel_input_open_confirmation(); + break; + + case SSH_MSG_CHANNEL_OPEN_FAILURE: + debug("Received channel open failure."); + packet_integrity_check(payload_len, 4, type); + channel_input_open_failure(); + break; + + case SSH_MSG_CHANNEL_DATA: + channel_input_data(payload_len); + break; + + case SSH_MSG_CHANNEL_CLOSE: + debug("Received channel close."); + packet_integrity_check(payload_len, 4, type); + channel_input_close(); + break; + + case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION: + debug("Received channel close confirmation."); + packet_integrity_check(payload_len, 4, type); + channel_input_close_confirmation(); + break; + + default: + /* In this phase, any unexpected messages cause a + protocol error. This is to ease debugging; + also, since no confirmations are sent messages, + unprocessed unknown messages could cause + strange problems. Any compatible protocol + extensions must be negotiated before entering + the interactive session. */ + packet_disconnect("Protocol error during session: type %d", + type); + } } - } } -/* Make packets from buffered stderr data, and buffer it for sending - to the client. */ - -void make_packets_from_stderr_data() +/* + * Make packets from buffered stderr data, and buffer it for sending + * to the client. + */ +void +make_packets_from_stderr_data() { - int len; - - /* Send buffered stderr data to the client. */ - while (buffer_len(&stderr_buffer) > 0 && - packet_not_very_much_data_to_write()) - { - len = buffer_len(&stderr_buffer); - if (packet_is_interactive()) - { - if (len > 512) - len = 512; - } - else - { - if (len > packet_get_maxsize()) - len = packet_get_maxsize(); /* Keep the packets at reasonable size. */ + int len; + + /* Send buffered stderr data to the client. */ + while (buffer_len(&stderr_buffer) > 0 && + packet_not_very_much_data_to_write()) { + len = buffer_len(&stderr_buffer); + if (packet_is_interactive()) { + if (len > 512) + len = 512; + } else { + /* Keep the packets at reasonable size. */ + if (len > packet_get_maxsize()) + len = packet_get_maxsize(); + } + packet_start(SSH_SMSG_STDERR_DATA); + packet_put_string(buffer_ptr(&stderr_buffer), len); + packet_send(); + buffer_consume(&stderr_buffer, len); + stderr_bytes += len; } - packet_start(SSH_SMSG_STDERR_DATA); - packet_put_string(buffer_ptr(&stderr_buffer), len); - packet_send(); - buffer_consume(&stderr_buffer, len); - stderr_bytes += len; - } } -/* Make packets from buffered stdout data, and buffer it for sending to the - client. */ - -void make_packets_from_stdout_data() +/* + * Make packets from buffered stdout data, and buffer it for sending to the + * client. + */ +void +make_packets_from_stdout_data() { - int len; - - /* Send buffered stdout data to the client. */ - while (buffer_len(&stdout_buffer) > 0 && - packet_not_very_much_data_to_write()) - { - len = buffer_len(&stdout_buffer); - if (packet_is_interactive()) - { - if (len > 512) - len = 512; - } - else - { - if (len > packet_get_maxsize()) - len = packet_get_maxsize(); /* Keep the packets at reasonable size. */ + int len; + + /* Send buffered stdout data to the client. */ + while (buffer_len(&stdout_buffer) > 0 && + packet_not_very_much_data_to_write()) { + len = buffer_len(&stdout_buffer); + if (packet_is_interactive()) { + if (len > 512) + len = 512; + } else { + /* Keep the packets at reasonable size. */ + if (len > packet_get_maxsize()) + len = packet_get_maxsize(); + } + packet_start(SSH_SMSG_STDOUT_DATA); + packet_put_string(buffer_ptr(&stdout_buffer), len); + packet_send(); + buffer_consume(&stdout_buffer, len); + stdout_bytes += len; } - packet_start(SSH_SMSG_STDOUT_DATA); - packet_put_string(buffer_ptr(&stdout_buffer), len); - packet_send(); - buffer_consume(&stdout_buffer, len); - stdout_bytes += len; - } } -/* Sleep in select() until we can do something. This will initialize the - select masks. Upon return, the masks will indicate which descriptors - have data or can accept data. Optionally, a maximum time can be specified - for the duration of the wait (0 = infinite). */ - -void wait_until_can_do_something(fd_set *readset, fd_set *writeset, - unsigned int max_time_milliseconds) +/* + * Sleep in select() until we can do something. This will initialize the + * select masks. Upon return, the masks will indicate which descriptors + * have data or can accept data. Optionally, a maximum time can be specified + * for the duration of the wait (0 = infinite). + */ +void +wait_until_can_do_something(fd_set * readset, fd_set * writeset, + unsigned int max_time_milliseconds) { - struct timeval tv, *tvp; - int ret; + struct timeval tv, *tvp; + int ret; - /* When select fails we restart from here. */ + /* When select fails we restart from here. */ retry_select: - /* Initialize select() masks. */ - FD_ZERO(readset); - - /* Read packets from the client unless we have too much buffered stdin - or channel data. */ - if (buffer_len(&stdin_buffer) < 4096 && - channel_not_very_much_buffered_data()) - FD_SET(connection_in, readset); - - /* If there is not too much data already buffered going to the client, - try to get some more data from the program. */ - if (packet_not_very_much_data_to_write()) - { - if (!fdout_eof) - FD_SET(fdout, readset); - if (!fderr_eof) - FD_SET(fderr, readset); - } - - FD_ZERO(writeset); - - /* Set masks for channel descriptors. */ - channel_prepare_select(readset, writeset); - - /* If we have buffered packet data going to the client, mark that - descriptor. */ - if (packet_have_data_to_write()) - FD_SET(connection_out, writeset); - - /* If we have buffered data, try to write some of that data to the - program. */ - if (fdin != -1 && buffer_len(&stdin_buffer) > 0) - FD_SET(fdin, writeset); - - /* Update the maximum descriptor number if appropriate. */ - if (channel_max_fd() > max_fd) - max_fd = channel_max_fd(); - - /* If child has terminated and there is enough buffer space to read from - it, then read as much as is available and exit. */ - if (child_terminated && packet_not_very_much_data_to_write()) - if (max_time_milliseconds == 0) - max_time_milliseconds = 100; - - if (max_time_milliseconds == 0) - tvp = NULL; - else - { - tv.tv_sec = max_time_milliseconds / 1000; - tv.tv_usec = 1000 * (max_time_milliseconds % 1000); - tvp = &tv; - } - - /* Wait for something to happen, or the timeout to expire. */ - ret = select(max_fd + 1, readset, writeset, NULL, tvp); - - if (ret < 0) - { - if (errno != EINTR) - error("select: %.100s", strerror(errno)); - else - goto retry_select; - } -} + /* Initialize select() masks. */ + FD_ZERO(readset); + + /* Read packets from the client unless we have too much buffered + stdin or channel data. */ + if (buffer_len(&stdin_buffer) < 4096 && + channel_not_very_much_buffered_data()) + FD_SET(connection_in, readset); + + /* If there is not too much data already buffered going to the + client, try to get some more data from the program. */ + if (packet_not_very_much_data_to_write()) { + if (!fdout_eof) + FD_SET(fdout, readset); + if (!fderr_eof) + FD_SET(fderr, readset); + } + FD_ZERO(writeset); + + /* Set masks for channel descriptors. */ + channel_prepare_select(readset, writeset); + + /* If we have buffered packet data going to the client, mark that + descriptor. */ + if (packet_have_data_to_write()) + FD_SET(connection_out, writeset); + + /* If we have buffered data, try to write some of that data to the + program. */ + if (fdin != -1 && buffer_len(&stdin_buffer) > 0) + FD_SET(fdin, writeset); + + /* Update the maximum descriptor number if appropriate. */ + if (channel_max_fd() > max_fd) + max_fd = channel_max_fd(); + + /* If child has terminated and there is enough buffer space to + read from it, then read as much as is available and exit. */ + if (child_terminated && packet_not_very_much_data_to_write()) + if (max_time_milliseconds == 0) + max_time_milliseconds = 100; + + if (max_time_milliseconds == 0) + tvp = NULL; + else { + tv.tv_sec = max_time_milliseconds / 1000; + tv.tv_usec = 1000 * (max_time_milliseconds % 1000); + tvp = &tv; + } -/* Processes input from the client and the program. Input data is stored - in buffers and processed later. */ + /* Wait for something to happen, or the timeout to expire. */ + ret = select(max_fd + 1, readset, writeset, NULL, tvp); -void process_input(fd_set *readset) -{ - int len; - char buf[16384]; - - /* Read and buffer any input data from the client. */ - if (FD_ISSET(connection_in, readset)) - { - len = read(connection_in, buf, sizeof(buf)); - if (len == 0) - fatal("Connection closed by remote host."); - - /* There is a kernel bug on Solaris that causes select to sometimes - wake up even though there is no data available. */ - if (len < 0 && errno == EAGAIN) - len = 0; - - if (len < 0) - fatal("Read error from remote host: %.100s", strerror(errno)); - - /* Buffer any received data. */ - packet_process_incoming(buf, len); - } - - /* Read and buffer any available stdout data from the program. */ - if (!fdout_eof && FD_ISSET(fdout, readset)) - { - len = read(fdout, buf, sizeof(buf)); - if (len <= 0) - fdout_eof = 1; - else - { - buffer_append(&stdout_buffer, buf, len); - fdout_bytes += len; + if (ret < 0) { + if (errno != EINTR) + error("select: %.100s", strerror(errno)); + else + goto retry_select; } - } - - /* Read and buffer any available stderr data from the program. */ - if (!fderr_eof && FD_ISSET(fderr, readset)) - { - len = read(fderr, buf, sizeof(buf)); - if (len <= 0) - fderr_eof = 1; - else - buffer_append(&stderr_buffer, buf, len); - } } -/* Sends data from internal buffers to client program stdin. */ +/* + * Processes input from the client and the program. Input data is stored + * in buffers and processed later. + */ +void +process_input(fd_set * readset) +{ + int len; + char buf[16384]; + + /* Read and buffer any input data from the client. */ + if (FD_ISSET(connection_in, readset)) { + len = read(connection_in, buf, sizeof(buf)); + if (len == 0) { + verbose("Connection closed by remote host."); + fatal_cleanup(); + } + /* There is a kernel bug on Solaris that causes select to + sometimes wake up even though there is no data + available. */ + if (len < 0 && errno == EAGAIN) + len = 0; + + if (len < 0) { + verbose("Read error from remote host: %.100s", strerror(errno)); + fatal_cleanup(); + } + /* Buffer any received data. */ + packet_process_incoming(buf, len); + } + /* Read and buffer any available stdout data from the program. */ + if (!fdout_eof && FD_ISSET(fdout, readset)) { + len = read(fdout, buf, sizeof(buf)); + if (len <= 0) + fdout_eof = 1; + else { + buffer_append(&stdout_buffer, buf, len); + fdout_bytes += len; + } + } + /* Read and buffer any available stderr data from the program. */ + if (!fderr_eof && FD_ISSET(fderr, readset)) { + len = read(fderr, buf, sizeof(buf)); + if (len <= 0) + fderr_eof = 1; + else + buffer_append(&stderr_buffer, buf, len); + } +} -void process_output(fd_set *writeset) +/* + * Sends data from internal buffers to client program stdin. + */ +void +process_output(fd_set * writeset) { - int len; - - /* Write buffered data to program stdin. */ - if (fdin != -1 && FD_ISSET(fdin, writeset)) - { - len = write(fdin, buffer_ptr(&stdin_buffer), - buffer_len(&stdin_buffer)); - if (len <= 0) - { + int len; + + /* Write buffered data to program stdin. */ + if (fdin != -1 && FD_ISSET(fdin, writeset)) { + len = write(fdin, buffer_ptr(&stdin_buffer), + buffer_len(&stdin_buffer)); + if (len <= 0) { #ifdef USE_PIPES - close(fdin); + close(fdin); #else - if (fdout == -1) - close(fdin); - else - shutdown(fdin, SHUT_WR); /* We will no longer send. */ + if (fdout == -1) + close(fdin); + else + shutdown(fdin, SHUT_WR); /* We will no longer send. */ #endif - fdin = -1; - } - else - { - /* Successful write. Consume the data from the buffer. */ - buffer_consume(&stdin_buffer, len); - /* Update the count of bytes written to the program. */ - stdin_bytes += len; + fdin = -1; + } else { + /* Successful write. Consume the data from the buffer. */ + buffer_consume(&stdin_buffer, len); + /* Update the count of bytes written to the program. */ + stdin_bytes += len; + } } - } - - /* Send any buffered packet data to the client. */ - if (FD_ISSET(connection_out, writeset)) - packet_write_poll(); + /* Send any buffered packet data to the client. */ + if (FD_ISSET(connection_out, writeset)) + packet_write_poll(); } -/* Wait until all buffered output has been sent to the client. - This is used when the program terminates. */ - -void drain_output() +/* + * Wait until all buffered output has been sent to the client. + * This is used when the program terminates. + */ +void +drain_output() { - /* Send any buffered stdout data to the client. */ - if (buffer_len(&stdout_buffer) > 0) - { - packet_start(SSH_SMSG_STDOUT_DATA); - packet_put_string(buffer_ptr(&stdout_buffer), - buffer_len(&stdout_buffer)); - packet_send(); - /* Update the count of sent bytes. */ - stdout_bytes += buffer_len(&stdout_buffer); - } - - /* Send any buffered stderr data to the client. */ - if (buffer_len(&stderr_buffer) > 0) - { - packet_start(SSH_SMSG_STDERR_DATA); - packet_put_string(buffer_ptr(&stderr_buffer), - buffer_len(&stderr_buffer)); - packet_send(); - /* Update the count of sent bytes. */ - stderr_bytes += buffer_len(&stderr_buffer); - } - - /* Wait until all buffered data has been written to the client. */ - packet_write_wait(); + /* Send any buffered stdout data to the client. */ + if (buffer_len(&stdout_buffer) > 0) { + packet_start(SSH_SMSG_STDOUT_DATA); + packet_put_string(buffer_ptr(&stdout_buffer), + buffer_len(&stdout_buffer)); + packet_send(); + /* Update the count of sent bytes. */ + stdout_bytes += buffer_len(&stdout_buffer); + } + /* Send any buffered stderr data to the client. */ + if (buffer_len(&stderr_buffer) > 0) { + packet_start(SSH_SMSG_STDERR_DATA); + packet_put_string(buffer_ptr(&stderr_buffer), + buffer_len(&stderr_buffer)); + packet_send(); + /* Update the count of sent bytes. */ + stderr_bytes += buffer_len(&stderr_buffer); + } + /* Wait until all buffered data has been written to the client. */ + packet_write_wait(); } -/* Performs the interactive session. This handles data transmission between - the client and the program. Note that the notion of stdin, stdout, and - stderr in this function is sort of reversed: this function writes to - stdin (of the child program), and reads from stdout and stderr (of the - child program). */ - -void server_loop(int pid, int fdin_arg, int fdout_arg, int fderr_arg) +/* + * Performs the interactive session. This handles data transmission between + * the client and the program. Note that the notion of stdin, stdout, and + * stderr in this function is sort of reversed: this function writes to + * stdin (of the child program), and reads from stdout and stderr (of the + * child program). + */ +void +server_loop(int pid, int fdin_arg, int fdout_arg, int fderr_arg) { - int wait_status, wait_pid; /* Status and pid returned by wait(). */ - int waiting_termination = 0; /* Have displayed waiting close message. */ - unsigned int max_time_milliseconds; - unsigned int previous_stdout_buffer_bytes; - unsigned int stdout_buffer_bytes; - int type; - - debug("Entering interactive session."); - - /* Initialize the SIGCHLD kludge. */ - child_pid = pid; - child_terminated = 0; - signal(SIGCHLD, sigchld_handler); - - /* Initialize our global variables. */ - fdin = fdin_arg; - fdout = fdout_arg; - fderr = fderr_arg; - connection_in = packet_get_connection_in(); - connection_out = packet_get_connection_out(); - - previous_stdout_buffer_bytes = 0; - - /* Set approximate I/O buffer size. */ - if (packet_is_interactive()) - buffer_high = 4096; - else - buffer_high = 64 * 1024; - - /* Initialize max_fd to the maximum of the known file descriptors. */ - max_fd = fdin; - if (fdout > max_fd) - max_fd = fdout; - if (fderr != -1 && fderr > max_fd) - max_fd = fderr; - if (connection_in > max_fd) - max_fd = connection_in; - if (connection_out > max_fd) - max_fd = connection_out; - - /* Initialize Initialize buffers. */ - buffer_init(&stdin_buffer); - buffer_init(&stdout_buffer); - buffer_init(&stderr_buffer); - - /* If we have no separate fderr (which is the case when we have a pty - there - we cannot make difference between data sent to stdout and stderr), - indicate that we have seen an EOF from stderr. This way we don\'t - need to check the descriptor everywhere. */ - if (fderr == -1) - fderr_eof = 1; - - /* Main loop of the server for the interactive session mode. */ - for (;;) - { - fd_set readset, writeset; - - /* Process buffered packets from the client. */ - process_buffered_input_packets(); - - /* If we have received eof, and there is no more pending input data, - cause a real eof by closing fdin. */ - if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) - { + int wait_status, wait_pid; /* Status and pid returned by wait(). */ + int waiting_termination = 0; /* Have displayed waiting close message. */ + unsigned int max_time_milliseconds; + unsigned int previous_stdout_buffer_bytes; + unsigned int stdout_buffer_bytes; + int type; + + debug("Entering interactive session."); + + /* Initialize the SIGCHLD kludge. */ + child_pid = pid; + child_terminated = 0; + signal(SIGCHLD, sigchld_handler); + + /* Initialize our global variables. */ + fdin = fdin_arg; + fdout = fdout_arg; + fderr = fderr_arg; + connection_in = packet_get_connection_in(); + connection_out = packet_get_connection_out(); + + previous_stdout_buffer_bytes = 0; + + /* Set approximate I/O buffer size. */ + if (packet_is_interactive()) + buffer_high = 4096; + else + buffer_high = 64 * 1024; + + /* Initialize max_fd to the maximum of the known file descriptors. */ + max_fd = fdin; + if (fdout > max_fd) + max_fd = fdout; + if (fderr != -1 && fderr > max_fd) + max_fd = fderr; + if (connection_in > max_fd) + max_fd = connection_in; + if (connection_out > max_fd) + max_fd = connection_out; + + /* Initialize Initialize buffers. */ + buffer_init(&stdin_buffer); + buffer_init(&stdout_buffer); + buffer_init(&stderr_buffer); + + /* If we have no separate fderr (which is the case when we have a + pty - there we cannot make difference between data sent to + stdout and stderr), indicate that we have seen an EOF from + stderr. This way we don\'t need to check the descriptor + everywhere. */ + if (fderr == -1) + fderr_eof = 1; + + /* Main loop of the server for the interactive session mode. */ + for (;;) { + fd_set readset, writeset; + + /* Process buffered packets from the client. */ + process_buffered_input_packets(); + + /* If we have received eof, and there is no more pending + input data, cause a real eof by closing fdin. */ + if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { #ifdef USE_PIPES - close(fdin); + close(fdin); #else - if (fdout == -1) - close(fdin); - else - shutdown(fdin, SHUT_WR); /* We will no longer send. */ + if (fdout == -1) + close(fdin); + else + shutdown(fdin, SHUT_WR); /* We will no longer send. */ #endif - fdin = -1; + fdin = -1; + } + /* Make packets from buffered stderr data to send to the + client. */ + make_packets_from_stderr_data(); + + /* Make packets from buffered stdout data to send to the + client. If there is very little to send, this arranges + to not send them now, but to wait a short while to see + if we are getting more data. This is necessary, as some + systems wake up readers from a pty after each separate + character. */ + max_time_milliseconds = 0; + stdout_buffer_bytes = buffer_len(&stdout_buffer); + if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && + stdout_buffer_bytes != previous_stdout_buffer_bytes) { + /* try again after a while */ + max_time_milliseconds = 10; + } else { + /* Send it now. */ + make_packets_from_stdout_data(); + } + previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); + + /* Send channel data to the client. */ + if (packet_not_very_much_data_to_write()) + channel_output_poll(); + + /* Bail out of the loop if the program has closed its + output descriptors, and we have no more data to send to + the client, and there is no pending buffered data. */ + if (fdout_eof && fderr_eof && !packet_have_data_to_write() && + buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { + if (!channel_still_open()) + goto quit; + if (!waiting_termination) { + const char *s = "Waiting for forwarded connections to terminate...\r\n"; + char *cp; + waiting_termination = 1; + buffer_append(&stderr_buffer, s, strlen(s)); + + /* Display list of open channels. */ + cp = channel_open_message(); + buffer_append(&stderr_buffer, cp, strlen(cp)); + xfree(cp); + } + } + /* Sleep in select() until we can do something. */ + wait_until_can_do_something(&readset, &writeset, + max_time_milliseconds); + + /* Process any channel events. */ + channel_after_select(&readset, &writeset); + + /* Process input from the client and from program stdout/stderr. */ + process_input(&readset); + + /* Process output to the client and to program stdin. */ + process_output(&writeset); } - /* Make packets from buffered stderr data to send to the client. */ - make_packets_from_stderr_data(); - - /* Make packets from buffered stdout data to send to the client. - If there is very little to send, this arranges to not send them - now, but to wait a short while to see if we are getting more data. - This is necessary, as some systems wake up readers from a pty after - each separate character. */ - max_time_milliseconds = 0; - stdout_buffer_bytes = buffer_len(&stdout_buffer); - if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && - stdout_buffer_bytes != previous_stdout_buffer_bytes) - max_time_milliseconds = 10; /* try again after a while */ - else - make_packets_from_stdout_data(); /* Send it now. */ - previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); - - /* Send channel data to the client. */ - if (packet_not_very_much_data_to_write()) - channel_output_poll(); - - /* Bail out of the loop if the program has closed its output descriptors, - and we have no more data to send to the client, and there is no - pending buffered data. */ - if (fdout_eof && fderr_eof && !packet_have_data_to_write() && - buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) - { - if (!channel_still_open()) - goto quit; - if (!waiting_termination) - { - const char *s = - "Waiting for forwarded connections to terminate...\r\n"; - char *cp; - waiting_termination = 1; - buffer_append(&stderr_buffer, s, strlen(s)); - - /* Display list of open channels. */ - cp = channel_open_message(); - buffer_append(&stderr_buffer, cp, strlen(cp)); - xfree(cp); - } - } +quit: + /* Cleanup and termination code. */ - /* Sleep in select() until we can do something. */ - wait_until_can_do_something(&readset, &writeset, - max_time_milliseconds); - - /* Process any channel events. */ - channel_after_select(&readset, &writeset); - - /* Process input from the client and from program stdout/stderr. */ - process_input(&readset); - - /* Process output to the client and to program stdin. */ - process_output(&writeset); - } - - quit: - /* Cleanup and termination code. */ - - /* Wait until all output has been sent to the client. */ - drain_output(); - - debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", - stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); - - /* Free and clear the buffers. */ - buffer_free(&stdin_buffer); - buffer_free(&stdout_buffer); - buffer_free(&stderr_buffer); - - /* Close the file descriptors. */ - if (fdout != -1) - close(fdout); - fdout = -1; - fdout_eof = 1; - if (fderr != -1) - close(fderr); - fderr = -1; - fderr_eof = 1; - if (fdin != -1) - close(fdin); - fdin = -1; - - /* Stop listening for channels; this removes unix domain sockets. */ - channel_stop_listening(); - - /* Wait for the child to exit. Get its exit status. */ - wait_pid = wait(&wait_status); - if (wait_pid < 0) - { - /* It is possible that the wait was handled by SIGCHLD handler. This - may result in either: this call returning with EINTR, or: this - call returning ECHILD. */ - if (child_terminated) - wait_status = child_wait_status; - else - packet_disconnect("wait: %.100s", strerror(errno)); - } - else - { - /* Check if it matches the process we forked. */ - if (wait_pid != pid) - error("Strange, wait returned pid %d, expected %d", wait_pid, pid); - } - - /* We no longer want our SIGCHLD handler to be called. */ - signal(SIGCHLD, SIG_DFL); - - /* Check if it exited normally. */ - if (WIFEXITED(wait_status)) - { - /* Yes, normal exit. Get exit status and send it to the client. */ - debug("Command exited with status %d.", WEXITSTATUS(wait_status)); - packet_start(SSH_SMSG_EXITSTATUS); - packet_put_int(WEXITSTATUS(wait_status)); - packet_send(); - packet_write_wait(); - - /* Wait for exit confirmation. Note that there might be other - packets coming before it; however, the program has already died - so we just ignore them. The client is supposed to respond with - the confirmation when it receives the exit status. */ - do - { - int plen; - type = packet_read(&plen); - } - while (type != SSH_CMSG_EXIT_CONFIRMATION); + /* Wait until all output has been sent to the client. */ + drain_output(); - debug("Received exit confirmation."); - return; - } + debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", + stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); - /* Check if the program terminated due to a signal. */ - if (WIFSIGNALED(wait_status)) - packet_disconnect("Command terminated on signal %d.", - WTERMSIG(wait_status)); + /* Free and clear the buffers. */ + buffer_free(&stdin_buffer); + buffer_free(&stdout_buffer); + buffer_free(&stderr_buffer); - /* Some weird exit cause. Just exit. */ - packet_disconnect("wait returned status %04x.", wait_status); - /*NOTREACHED*/ -} + /* Close the file descriptors. */ + if (fdout != -1) + close(fdout); + fdout = -1; + fdout_eof = 1; + if (fderr != -1) + close(fderr); + fderr = -1; + fderr_eof = 1; + if (fdin != -1) + close(fdin); + fdin = -1; + + /* Stop listening for channels; this removes unix domain sockets. */ + channel_stop_listening(); + + /* Wait for the child to exit. Get its exit status. */ + wait_pid = wait(&wait_status); + if (wait_pid < 0) { + /* + * It is possible that the wait was handled by SIGCHLD + * handler. This may result in either: this call + * returning with EINTR, or: this call returning ECHILD. + */ + if (child_terminated) + wait_status = child_wait_status; + else + packet_disconnect("wait: %.100s", strerror(errno)); + } else { + /* Check if it matches the process we forked. */ + if (wait_pid != pid) + error("Strange, wait returned pid %d, expected %d", + wait_pid, pid); + } + /* We no longer want our SIGCHLD handler to be called. */ + signal(SIGCHLD, SIG_DFL); + + /* Check if it exited normally. */ + if (WIFEXITED(wait_status)) { + /* Yes, normal exit. Get exit status and send it to the client. */ + debug("Command exited with status %d.", WEXITSTATUS(wait_status)); + packet_start(SSH_SMSG_EXITSTATUS); + packet_put_int(WEXITSTATUS(wait_status)); + packet_send(); + packet_write_wait(); + + /* Wait for exit confirmation. Note that there might be + other packets coming before it; however, the program + has already died so we just ignore them. The client is + supposed to respond with the confirmation when it + receives the exit status. */ + do { + int plen; + type = packet_read(&plen); + } + while (type != SSH_CMSG_EXIT_CONFIRMATION); + + debug("Received exit confirmation."); + return; + } + /* Check if the program terminated due to a signal. */ + if (WIFSIGNALED(wait_status)) + packet_disconnect("Command terminated on signal %d.", + WTERMSIG(wait_status)); + + /* Some weird exit cause. Just exit. */ + packet_disconnect("wait returned status %04x.", wait_status); + /* NOTREACHED */ +} |