- Merged very large OpenBSD source code reformat
- OpenBSD CVS updates
- [channels.c cipher.c compat.c log-client.c scp.c serverloop.c]
[ssh.h sshd.8 sshd.c]
syslog changes:
* Unified Logmessage for all auth-types, for success and for failed
* Standard connections get only ONE line in the LOG when level==LOG:
Auth-attempts are logged only, if authentication is:
a) successfull or
b) with passwd or
c) we had more than AUTH_FAIL_LOG failues
* many log() became verbose()
* old behaviour with level=VERBOSE
- [readconf.c readconf.h ssh.1 ssh.h sshconnect.c sshd.c]
tranfer s/key challenge/response data in SSH_SMSG_AUTH_TIS_CHALLENGE
messages. allows use of s/key in windows (ttssh, securecrt) and
ssh-1.2.27 clients without 'ssh -v', ok: niels@
- [sshd.8]
-V, for fallback to openssh in SSH2 compatibility mode
- [sshd.c]
fix sigchld race; cjc5@po.cwru.edu
diff --git a/serverloop.c b/serverloop.c
index 9961170..fc959ba 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 @@
/* 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;
+ 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;
+ /* 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_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_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_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_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_CHANNEL_CLOSE_CONFIRMATION:
- debug("Received channel close confirmation.");
- packet_integrity_check(payload_len, 4, type);
- channel_input_close_confirmation();
- break;
+ case SSH_MSG_PORT_OPEN:
+ debug("Received port open request.");
+ channel_input_port_open(payload_len);
+ 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);
+ 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;
+ 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;
+ /* 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;
}
- else
- {
- if (len > packet_get_maxsize())
- len = packet_get_maxsize(); /* Keep the packets at reasonable size. */
- }
- 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;
+ 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;
+ /* 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;
}
- else
- {
- if (len > packet_get_maxsize())
- len = packet_get_maxsize(); /* Keep the packets at reasonable size. */
- }
- 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;
- }
+ /* Initialize select() masks. */
+ FD_ZERO(readset);
- /* 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;
- }
+ /* 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;
+ }
}
-/* Processes input from the client and the program. Input data is stored
- in buffers and processed later. */
-
-void process_input(fd_set *readset)
+/*
+ * 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];
+ 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.");
+ /* 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;
- /* 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);
+ }
+}
- if (len < 0)
- fatal("Read error from remote host: %.100s", strerror(errno));
+/*
+ * Sends data from internal buffers to client program stdin.
+ */
+void
+process_output(fd_set * writeset)
+{
+ int len;
- /* 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)
+ /* 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);
+#else
+ 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;
+ }
+ }
+ /* 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()
+{
+ /* 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)
+{
+ 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);
+#else
+ if (fdout == -1)
+ 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())
+ 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);
+ }
+
+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;
- 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)
+ if (fderr != -1)
+ close(fderr);
+ fderr = -1;
fderr_eof = 1;
- else
- buffer_append(&stderr_buffer, buf, len);
- }
+ 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 */
}
-
-/* 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)
- {
-#ifdef USE_PIPES
- close(fdin);
-#else
- 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;
- }
- }
-
- /* 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()
-{
- /* 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)
-{
- 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);
-#else
- if (fdout == -1)
- 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)
- 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);
- }
- }
-
- /* 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);
-
- 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*/
-}
-