packetstorm sync

1 files changed, 1003 insertions, 0 deletions

diff --git a/other/ssharp/serverloop.c b/other/ssharp/serverloop.c
new file mode 100644
index 0000000..21e4918
--- /dev/null
+++ b/other/ssharp/serverloop.c
@@ -0,0 +1,1003 @@
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * Server main loop for handling the interactive session.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ * SSH2 support by Markus Friedl.
+ * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+RCSID("$OpenBSD: serverloop.c,v 1.61 2001/04/13 22:46:54 beck Exp $");
+
+#include "xmalloc.h"
+#include "packet.h"
+#include "buffer.h"
+#include "log.h"
+#include "servconf.h"
+#include "sshpty.h"
+#include "channels.h"
+#include "compat.h"
+#include "ssh1.h"
+#include "ssh2.h"
+#include "auth.h"
+#include "session.h"
+#include "dispatch.h"
+#include "auth-options.h"
+#include "serverloop.h"
+#include "misc.h"
+#include "kex.h"
+
+extern ServerOptions options;
+
+/* XXX */
+extern Kex *xxx_kex;
+
+static Buffer stdin_buffer;     /* Buffer for stdin data. */
+static Buffer stdout_buffer;    /* Buffer for stdout data. */
+static Buffer stderr_buffer;    /* Buffer for stderr data. */
+static int fdin;                /* Descriptor for stdin (for writing) */
+static int fdout;               /* Descriptor for stdout (for reading);
+                                   May be same number as fdin. */
+static int fderr;               /* Descriptor for stderr.  May be -1. */
+static long stdin_bytes = 0;    /* Number of bytes written to stdin. */
+static long stdout_bytes = 0;   /* Number of stdout bytes sent to client. */
+static long stderr_bytes = 0;   /* Number of stderr bytes sent to client. */
+static long fdout_bytes = 0;    /* Number of stdout bytes read from program. */
+static int stdin_eof = 0;       /* EOF message received from client. */
+static int fdout_eof = 0;       /* EOF encountered reading from fdout. */
+static int fderr_eof = 0;       /* EOF encountered readung from fderr. */
+static int fdin_is_tty = 0;     /* fdin points to a tty. */
+static int connection_in;       /* Connection to client (input). */
+static int connection_out;      /* Connection to client (output). */
+static int connection_closed = 0;       /* Connection to client closed. */
+static u_int buffer_high;       /* "Soft" max buffer size. */
+
+/*
+ * 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 pid_t 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    server_init_dispatch(void);
+
+int client_alive_timeouts = 0;
+
+void
+sigchld_handler(int sig)
+{
+        int save_errno = errno;
+        pid_t 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;
+}
+void
+sigchld_handler2(int sig)
+{
+        int save_errno = errno;
+        debug("Received SIGCHLD.");
+        child_terminated = 1;
+        mysignal(SIGCHLD, sigchld_handler2);
+        errno = save_errno;
+}
+
+/*
+ * Make packets from buffered stderr data, and buffer it for sending
+ * to the client.
+ */
+void
+make_packets_from_stderr_data(void)
+{
+        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;
+        }
+}
+
+/*
+ * Make packets from buffered stdout data, and buffer it for sending to the
+ * client.
+ */
+void
+make_packets_from_stdout_data(void)
+{
+        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;
+        }
+}
+
+/*
+ * 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 **readsetp, fd_set **writesetp, int *maxfdp,
+    u_int max_time_milliseconds)
+{
+        struct timeval tv, *tvp;
+        int ret;
+        int client_alive_scheduled = 0;
+
+        /*
+         * if using client_alive, set the max timeout accordingly, 
+         * and indicate that this particular timeout was for client
+         * alive by setting the client_alive_scheduled flag.
+         *
+         * this could be randomized somewhat to make traffic
+         * analysis more difficult, but we're not doing it yet.  
+         */
+        if (max_time_milliseconds == 0 && options.client_alive_interval) {
+                client_alive_scheduled = 1;
+                max_time_milliseconds = options.client_alive_interval * 1000;
+        } else 
+                client_alive_scheduled = 0;
+
+        /* When select fails we restart from here. */
+retry_select:
+
+        /* Allocate and update select() masks for channel descriptors. */
+        channel_prepare_select(readsetp, writesetp, maxfdp, 0);
+
+        if (compat20) {
+                /* wrong: bad condition XXX */
+                if (channel_not_very_much_buffered_data())
+                        FD_SET(connection_in, *readsetp);
+        } else {
+                /*
+                 * Read packets from the client unless we have too much
+                 * buffered stdin or channel data.
+                 */
+                if (buffer_len(&stdin_buffer) < buffer_high &&
+                    channel_not_very_much_buffered_data())
+                        FD_SET(connection_in, *readsetp);
+                /*
+                 * 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, *readsetp);
+                        if (!fderr_eof)
+                                FD_SET(fderr, *readsetp);
+                }
+                /*
+                 * 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, *writesetp);
+        }
+
+        /*
+         * If we have buffered packet data going to the client, mark that
+         * descriptor.
+         */
+        if (packet_have_data_to_write())
+                FD_SET(connection_out, *writesetp);
+
+        /*
+         * 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 || client_alive_scheduled)
+                        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;
+        }
+        if (tvp!=NULL)
+                debug3("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds);
+
+        /* Wait for something to happen, or the timeout to expire. */
+        ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
+
+        if (ret == -1) {
+                if (errno != EINTR)
+                        error("select: %.100s", strerror(errno));
+                else
+                        goto retry_select;
+        }
+        if (ret == 0 && client_alive_scheduled) {
+                /* timeout, check to see how many we have had */
+                client_alive_timeouts++;
+
+                if (client_alive_timeouts > options.client_alive_count_max ) {
+                        packet_disconnect(
+                                "Timeout, your session not responding.");
+                } else {
+                        /*
+                         * send a bogus channel request with "wantreply" 
+                         * we should get back a failure
+                         */
+                        int id;
+                        
+                        id = channel_find_open();
+                        if (id != -1) {
+                                channel_request_start(id,
+                                  "keepalive@openssh.com", 1);
+                                packet_send();
+                        } else 
+                                packet_disconnect(
+                                        "No open channels after timeout!");
+                }
+        } 
+}
+
+/*
+ * 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.");
+                        connection_closed = 1;
+                        if (compat20)
+                                return;
+                        fatal_cleanup();
+                } else if (len < 0) {
+                        if (errno != EINTR && errno != EAGAIN) {
+                                verbose("Read error from remote host: %.100s", strerror(errno));
+                                fatal_cleanup();
+                        }
+                } else {
+                        /* Buffer any received data. */
+                        packet_process_incoming(buf, len);
+                }
+        }
+        if (compat20)
+                return;
+
+        /* 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 && (errno == EINTR || errno == EAGAIN)) {
+                        /* do nothing */
+                } else 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 && (errno == EINTR || errno == EAGAIN)) {
+                        /* do nothing */
+                } else if (len <= 0) {
+                        fderr_eof = 1;
+                } else {
+                        buffer_append(&stderr_buffer, buf, len);
+                }
+        }
+}
+
+/*
+ * Sends data from internal buffers to client program stdin.
+ */
+void
+process_output(fd_set * writeset)
+{
+        struct termios tio;
+        int len;
+
+        /* Write buffered data to program stdin. */
+        if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
+                len = write(fdin, buffer_ptr(&stdin_buffer),
+                    buffer_len(&stdin_buffer));
+                if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+                        /* do nothing */
+                } else if (len <= 0) {
+#ifdef USE_PIPES
+                        close(fdin);
+#else
+                        if (fdin != fdout)
+                                close(fdin);
+                        else
+                                shutdown(fdin, SHUT_WR); /* We will no longer send. */
+#endif
+                        fdin = -1;
+                } else {
+                        /* Successful write. */
+                        if (fdin_is_tty && tcgetattr(fdin, &tio) == 0 &&
+                            !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
+                                /*
+                                 * Simulate echo to reduce the impact of
+                                 * traffic analysis
+                                 */
+                                packet_send_ignore(len);
+                                packet_send();
+                        }
+                        /* 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();
+}
+
+/*
+ * Wait until all buffered output has been sent to the client.
+ * This is used when the program terminates.
+ */
+void
+drain_output(void)
+{
+        /* 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();
+}
+
+void
+process_buffered_input_packets(void)
+{
+        dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
+}
+
+/*
+ * 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(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
+{
+        fd_set *readset = NULL, *writeset = NULL;
+        int max_fd;
+        int wait_status;        /* Status returned by wait(). */
+        pid_t wait_pid;         /* pid returned by wait(). */
+        int waiting_termination = 0;    /* Have displayed waiting close message. */
+        u_int max_time_milliseconds;
+        u_int previous_stdout_buffer_bytes;
+        u_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;
+
+        /* nonblocking IO */
+        set_nonblock(fdin);
+        set_nonblock(fdout);
+        /* we don't have stderr for interactive terminal sessions, see below */
+        if (fderr != -1)
+                set_nonblock(fderr);
+
+        if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
+                fdin_is_tty = 1;
+
+        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 = MAX(fdin, fdout);
+        if (fderr != -1)
+                max_fd = MAX(max_fd, fderr);
+        max_fd = MAX(max_fd, connection_in);
+        max_fd = MAX(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;
+
+        server_init_dispatch();
+
+        /* Main loop of the server for the interactive session mode. */
+        for (;;) {
+
+                /* 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);
+#else
+                        if (fdin != fdout)
+                                close(fdin);
+                        else
+                                shutdown(fdin, SHUT_WR); /* We will no longer send. */
+#endif
+                        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())
+                                break;
+                        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_fd,
+                    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);
+        }
+        if (readset)
+                xfree(readset);
+        if (writeset)
+                xfree(writeset);
+
+        /* 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 == -1) {
+                /*
+                 * 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 */
+}
+
+void
+server_loop2(Authctxt *authctxt)
+{
+        fd_set *readset = NULL, *writeset = NULL;
+        int rekeying = 0, max_fd, status;
+        pid_t pid;
+
+        debug("Entering interactive session for SSH2.");
+
+        mysignal(SIGCHLD, sigchld_handler2);
+        child_terminated = 0;
+        connection_in = packet_get_connection_in();
+        connection_out = packet_get_connection_out();
+
+        max_fd = MAX(connection_in, connection_out);
+
+        server_init_dispatch();
+
+        for (;;) {
+                process_buffered_input_packets();
+
+                rekeying = (xxx_kex != NULL && !xxx_kex->done);
+
+                if (!rekeying && packet_not_very_much_data_to_write())
+                        channel_output_poll();
+                wait_until_can_do_something(&readset, &writeset, &max_fd,
+                    rekeying);
+                if (child_terminated) {
+                        while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+                                session_close_by_pid(pid, status);
+                        child_terminated = 0;
+                }
+                if (!rekeying)
+                        channel_after_select(readset, writeset);
+                process_input(readset);
+                if (connection_closed)
+                        break;
+                process_output(writeset);
+        }
+        if (readset)
+                xfree(readset);
+        if (writeset)
+                xfree(writeset);
+
+        signal(SIGCHLD, SIG_DFL);
+        while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+                session_close_by_pid(pid, status);
+        channel_stop_listening();
+}
+
+void
+server_input_channel_failure(int type, int plen, void *ctxt)
+{
+        debug("Got CHANNEL_FAILURE for keepalive");
+        /* 
+         * reset timeout, since we got a sane answer from the client.
+         * even if this was generated by something other than
+         * the bogus CHANNEL_REQUEST we send for keepalives.
+         */
+        client_alive_timeouts = 0; 
+}
+
+
+void
+server_input_stdin_data(int type, int plen, void *ctxt)
+{
+        char *data;
+        u_int data_len;
+
+        /* Stdin data from the client.  Append it to the buffer. */
+        /* Ignore any data if the client has closed stdin. */
+        if (fdin == -1)
+                return;
+        data = packet_get_string(&data_len);
+        packet_integrity_check(plen, (4 + data_len), type);
+        buffer_append(&stdin_buffer, data, data_len);
+        memset(data, 0, data_len);
+        xfree(data);
+}
+
+void
+server_input_eof(int type, int plen, void *ctxt)
+{
+        /*
+         * 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(plen, 0, type);
+        stdin_eof = 1;
+}
+
+void
+server_input_window_size(int type, int plen, void *ctxt)
+{
+        int row = packet_get_int();
+        int col = packet_get_int();
+        int xpixel = packet_get_int();
+        int ypixel = packet_get_int();
+
+        debug("Window change received.");
+        packet_integrity_check(plen, 4 * 4, type);
+        if (fdin != -1)
+                pty_change_window_size(fdin, row, col, xpixel, ypixel);
+}
+
+Channel *
+server_request_direct_tcpip(char *ctype)
+{
+        int sock, newch;
+        char *target, *originator;
+        int target_port, originator_port;
+
+        target = packet_get_string(NULL);
+        target_port = packet_get_int();
+        originator = packet_get_string(NULL);
+        originator_port = packet_get_int();
+        packet_done();
+
+        debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
+           originator, originator_port, target, target_port);
+
+        /* XXX check permission */
+        sock = channel_connect_to(target, target_port);
+        xfree(target);
+        xfree(originator);
+        if (sock < 0)
+                return NULL;
+        newch = channel_new(ctype, SSH_CHANNEL_CONNECTING,
+            sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
+            CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1);
+        return (newch >= 0) ? channel_lookup(newch) : NULL;
+}
+
+Channel *
+server_request_session(char *ctype)
+{
+        int newch;
+
+        debug("input_session_request");
+        packet_done();
+        /*
+         * A server session has no fd to read or write until a
+         * CHANNEL_REQUEST for a shell is made, so we set the type to
+         * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
+         * CHANNEL_REQUEST messages is registered.
+         */
+        newch = channel_new(ctype, SSH_CHANNEL_LARVAL,
+            -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT,
+            0, xstrdup("server-session"), 1);
+        if (session_open(newch) == 1) {
+                channel_register_callback(newch, SSH2_MSG_CHANNEL_REQUEST,
+                    session_input_channel_req, (void *)0);
+                channel_register_cleanup(newch, session_close_by_channel);
+                return channel_lookup(newch);
+        } else {
+                debug("session open failed, free channel %d", newch);
+                channel_free(newch);
+        }
+        return NULL;
+}
+
+void
+server_input_channel_open(int type, int plen, void *ctxt)
+{
+        Channel *c = NULL;
+        char *ctype;
+        u_int len;
+        int rchan;
+        int rmaxpack;
+        int rwindow;
+
+        ctype = packet_get_string(&len);
+        rchan = packet_get_int();
+        rwindow = packet_get_int();
+        rmaxpack = packet_get_int();
+
+        debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
+            ctype, rchan, rwindow, rmaxpack);
+
+        if (strcmp(ctype, "session") == 0) {
+                c = server_request_session(ctype);
+        } else if (strcmp(ctype, "direct-tcpip") == 0) {
+                c = server_request_direct_tcpip(ctype);
+        }
+        if (c != NULL) {
+                debug("server_input_channel_open: confirm %s", ctype);
+                c->remote_id = rchan;
+                c->remote_window = rwindow;
+                c->remote_maxpacket = rmaxpack;
+
+                packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
+                packet_put_int(c->remote_id);
+                packet_put_int(c->self);
+                packet_put_int(c->local_window);
+                packet_put_int(c->local_maxpacket);
+                packet_send();
+        } else {
+                debug("server_input_channel_open: failure %s", ctype);
+                packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
+                packet_put_int(rchan);
+                packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
+                packet_put_cstring("bla bla");
+                packet_put_cstring("");
+                packet_send();
+        }
+        xfree(ctype);
+}
+
+void
+server_input_global_request(int type, int plen, void *ctxt)
+{
+        char *rtype;
+        int want_reply;
+        int success = 0;
+
+        rtype = packet_get_string(NULL);
+        want_reply = packet_get_char();
+        debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
+
+        /* -R style forwarding */
+        if (strcmp(rtype, "tcpip-forward") == 0) {
+                char *listen_address;
+                u_short listen_port;
+
+                listen_address = packet_get_string(NULL); /* XXX currently ignored */
+                listen_port = (u_short)packet_get_int();
+                debug("server_input_global_request: tcpip-forward listen %s port %d",
+                    listen_address, listen_port);
+
+                /* check permissions */
+                if (!options.allow_tcp_forwarding ||
+                    no_port_forwarding_flag ||
+                    (listen_port < IPPORT_RESERVED)) {
+                        success = 0;
+                        packet_send_debug("Server has disabled port forwarding.");
+                } else {
+                        /* Start listening on the port */
+                        success = channel_request_forwarding(
+                            listen_address, listen_port,
+                            /*unspec host_to_connect*/ "<unspec host>",
+                            /*unspec port_to_connect*/ 0,
+                            options.gateway_ports, /*remote*/ 1);
+                }
+                xfree(listen_address);
+        }
+        if (want_reply) {
+                packet_start(success ?
+                    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
+                packet_send();
+                packet_write_wait();
+        }
+        xfree(rtype);
+}
+
+void
+server_init_dispatch_20(void)
+{
+        debug("server_init_dispatch_20");
+        dispatch_init(&dispatch_protocol_error);
+        dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
+        dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
+        dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
+        dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
+        dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
+        dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
+        dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
+        dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
+        dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
+        dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
+        /* client_alive */
+        dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_channel_failure);
+        /* rekeying */
+        dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
+}
+void
+server_init_dispatch_13(void)
+{
+        debug("server_init_dispatch_13");
+        dispatch_init(NULL);
+        dispatch_set(SSH_CMSG_EOF, &server_input_eof);
+        dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
+        dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
+        dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
+        dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
+        dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
+        dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
+        dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
+        dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
+}
+void
+server_init_dispatch_15(void)
+{
+        server_init_dispatch_13();
+        debug("server_init_dispatch_15");
+        dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
+        dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
+}
+void
+server_init_dispatch(void)
+{
+        if (compat20)
+                server_init_dispatch_20();
+        else if (compat13)
+                server_init_dispatch_13();
+        else
+                server_init_dispatch_15();
+}
+