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putty-source/unix/uxplink.c
Simon Tatham 5c926d9ea4 Switch to using poll(2) in place of select(2). 
I've always thought poll was more hassle to set up, because if you
want to reuse part of your pollfds list between calls then you have to
index every fd by its position in the list as well as the fd number
itself, which gives you twice as many indices to keep track of than if
the fd is always its own key.

But the problem is that select is fundamentally limited to the range
of fds that can fit in an fd_set, which is not the range of fds that
can _exist_, so I've had a change of heart and now have to go with
poll.

For the moment, I've surrounded it with a 'pollwrapper' structure that
lets me treat it more or less like select, containing a tree234 that
maps each fd to its location in the list, and also translating between
the simple select r/w/x classification and the richer poll flags.
That's let me do the migration with minimal disruption to the call
sites.

In future perhaps I can start using poll more directly, and/or using
the richer flag system (though the latter might be fiddly because of
sometimes being constrained to use the glib event loop). But this will
do for now.
2019-03-16 12:25:23 +00:00

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/*
* PLink - a command-line (stdin/stdout) variant of PuTTY.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <stdarg.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <pwd.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#define PUTTY_DO_GLOBALS /* actually _define_ globals */
#include "putty.h"
#include "storage.h"
#include "tree234.h"
#define MAX_STDIN_BACKLOG 4096
static LogContext *logctx;
static struct termios orig_termios;
void cmdline_error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
console_print_error_msg_fmt_v("plink", fmt, ap);
va_end(ap);
exit(1);
}
static bool local_tty = false; /* do we have a local tty? */
static Backend *backend;
Conf *conf;
/*
* Default settings that are specific to Unix plink.
*/
char *platform_default_s(const char *name)
{
if (!strcmp(name, "TermType"))
return dupstr(getenv("TERM"));
if (!strcmp(name, "SerialLine"))
return dupstr("/dev/ttyS0");
return NULL;
}
bool platform_default_b(const char *name, bool def)
{
return def;
}
int platform_default_i(const char *name, int def)
{
return def;
}
FontSpec *platform_default_fontspec(const char *name)
{
return fontspec_new("");
}
Filename *platform_default_filename(const char *name)
{
if (!strcmp(name, "LogFileName"))
return filename_from_str("putty.log");
else
return filename_from_str("");
}
char *x_get_default(const char *key)
{
return NULL; /* this is a stub */
}
bool term_ldisc(Terminal *term, int mode)
{
return false;
}
static void plink_echoedit_update(Seat *seat, bool echo, bool edit)
{
/* Update stdin read mode to reflect changes in line discipline. */
struct termios mode;
if (!local_tty) return;
mode = orig_termios;
if (echo)
mode.c_lflag |= ECHO;
else
mode.c_lflag &= ~ECHO;
if (edit) {
mode.c_iflag |= ICRNL;
mode.c_lflag |= ISIG | ICANON;
mode.c_oflag |= OPOST;
} else {
mode.c_iflag &= ~ICRNL;
mode.c_lflag &= ~(ISIG | ICANON);
mode.c_oflag &= ~OPOST;
/* Solaris sets these to unhelpful values */
mode.c_cc[VMIN] = 1;
mode.c_cc[VTIME] = 0;
/* FIXME: perhaps what we do with IXON/IXOFF should be an
* argument to the echoedit_update() method, to allow
* implementation of SSH-2 "xon-xoff" and Rlogin's
* equivalent? */
mode.c_iflag &= ~IXON;
mode.c_iflag &= ~IXOFF;
}
/*
* Mark parity errors and (more important) BREAK on input. This
* is more complex than it need be because POSIX-2001 suggests
* that escaping of valid 0xff in the input stream is dependent on
* IGNPAR being clear even though marking of BREAK isn't. NetBSD
* 2.0 goes one worse and makes it dependent on INPCK too. We
* deal with this by forcing these flags into a useful state and
* then faking the state in which we found them in from_tty() if
* we get passed a parity or framing error.
*/
mode.c_iflag = (mode.c_iflag | INPCK | PARMRK) & ~IGNPAR;
tcsetattr(STDIN_FILENO, TCSANOW, &mode);
}
/* Helper function to extract a special character from a termios. */
static char *get_ttychar(struct termios *t, int index)
{
cc_t c = t->c_cc[index];
#if defined(_POSIX_VDISABLE)
if (c == _POSIX_VDISABLE)
return dupstr("");
#endif
return dupprintf("^<%d>", c);
}
static char *plink_get_ttymode(Seat *seat, const char *mode)
{
/*
* Propagate appropriate terminal modes from the local terminal,
* if any.
*/
if (!local_tty) return NULL;
#define GET_CHAR(ourname, uxname) \
do { \
if (strcmp(mode, ourname) == 0) \
return get_ttychar(&orig_termios, uxname); \
} while(0)
#define GET_BOOL(ourname, uxname, uxmemb, transform) \
do { \
if (strcmp(mode, ourname) == 0) { \
bool b = (orig_termios.uxmemb & uxname) != 0; \
transform; \
return dupprintf("%d", b); \
} \
} while (0)
/*
* Modes that want to be the same on all terminal devices involved.
*/
/* All the special characters supported by SSH */
#if defined(VINTR)
GET_CHAR("INTR", VINTR);
#endif
#if defined(VQUIT)
GET_CHAR("QUIT", VQUIT);
#endif
#if defined(VERASE)
GET_CHAR("ERASE", VERASE);
#endif
#if defined(VKILL)
GET_CHAR("KILL", VKILL);
#endif
#if defined(VEOF)
GET_CHAR("EOF", VEOF);
#endif
#if defined(VEOL)
GET_CHAR("EOL", VEOL);
#endif
#if defined(VEOL2)
GET_CHAR("EOL2", VEOL2);
#endif
#if defined(VSTART)
GET_CHAR("START", VSTART);
#endif
#if defined(VSTOP)
GET_CHAR("STOP", VSTOP);
#endif
#if defined(VSUSP)
GET_CHAR("SUSP", VSUSP);
#endif
#if defined(VDSUSP)
GET_CHAR("DSUSP", VDSUSP);
#endif
#if defined(VREPRINT)
GET_CHAR("REPRINT", VREPRINT);
#endif
#if defined(VWERASE)
GET_CHAR("WERASE", VWERASE);
#endif
#if defined(VLNEXT)
GET_CHAR("LNEXT", VLNEXT);
#endif
#if defined(VFLUSH)
GET_CHAR("FLUSH", VFLUSH);
#endif
#if defined(VSWTCH)
GET_CHAR("SWTCH", VSWTCH);
#endif
#if defined(VSTATUS)
GET_CHAR("STATUS", VSTATUS);
#endif
#if defined(VDISCARD)
GET_CHAR("DISCARD", VDISCARD);
#endif
/* Modes that "configure" other major modes. These should probably be
* considered as user preferences. */
/* Configuration of ICANON */
#if defined(ECHOK)
GET_BOOL("ECHOK", ECHOK, c_lflag, );
#endif
#if defined(ECHOKE)
GET_BOOL("ECHOKE", ECHOKE, c_lflag, );
#endif
#if defined(ECHOE)
GET_BOOL("ECHOE", ECHOE, c_lflag, );
#endif
#if defined(ECHONL)
GET_BOOL("ECHONL", ECHONL, c_lflag, );
#endif
#if defined(XCASE)
GET_BOOL("XCASE", XCASE, c_lflag, );
#endif
#if defined(IUTF8)
GET_BOOL("IUTF8", IUTF8, c_iflag, );
#endif
/* Configuration of ECHO */
#if defined(ECHOCTL)
GET_BOOL("ECHOCTL", ECHOCTL, c_lflag, );
#endif
/* Configuration of IXON/IXOFF */
#if defined(IXANY)
GET_BOOL("IXANY", IXANY, c_iflag, );
#endif
/* Configuration of OPOST */
#if defined(OLCUC)
GET_BOOL("OLCUC", OLCUC, c_oflag, );
#endif
#if defined(ONLCR)
GET_BOOL("ONLCR", ONLCR, c_oflag, );
#endif
#if defined(OCRNL)
GET_BOOL("OCRNL", OCRNL, c_oflag, );
#endif
#if defined(ONOCR)
GET_BOOL("ONOCR", ONOCR, c_oflag, );
#endif
#if defined(ONLRET)
GET_BOOL("ONLRET", ONLRET, c_oflag, );
#endif
/*
* Modes that want to be set in only one place, and that we have
* squashed locally.
*/
#if defined(ISIG)
GET_BOOL("ISIG", ISIG, c_lflag, );
#endif
#if defined(ICANON)
GET_BOOL("ICANON", ICANON, c_lflag, );
#endif
#if defined(ECHO)
GET_BOOL("ECHO", ECHO, c_lflag, );
#endif
#if defined(IXON)
GET_BOOL("IXON", IXON, c_iflag, );
#endif
#if defined(IXOFF)
GET_BOOL("IXOFF", IXOFF, c_iflag, );
#endif
#if defined(OPOST)
GET_BOOL("OPOST", OPOST, c_oflag, );
#endif
/*
* We do not propagate the following modes:
* - Parity/serial settings, which are a local affair and don't
* make sense propagated over SSH's 8-bit byte-stream.
* IGNPAR PARMRK INPCK CS7 CS8 PARENB PARODD
* - Things that want to be enabled in one place that we don't
* squash locally.
* IUCLC
* - Status bits.
* PENDIN
* - Things I don't know what to do with. (FIXME)
* ISTRIP IMAXBEL NOFLSH TOSTOP IEXTEN
* INLCR IGNCR ICRNL
*/
#undef GET_CHAR
#undef GET_BOOL
/* Fall through to here for unrecognised names, or ones that are
* unsupported on this platform */
return NULL;
}
void cleanup_termios(void)
{
if (local_tty)
tcsetattr(STDIN_FILENO, TCSANOW, &orig_termios);
}
bufchain stdout_data, stderr_data;
bufchain_sink stdout_bcs, stderr_bcs;
StripCtrlChars *stdout_scc, *stderr_scc;
BinarySink *stdout_bs, *stderr_bs;
enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;
size_t try_output(bool is_stderr)
{
bufchain *chain = (is_stderr ? &stderr_data : &stdout_data);
int fd = (is_stderr ? STDERR_FILENO : STDOUT_FILENO);
ssize_t ret;
if (bufchain_size(chain) > 0) {
bool prev_nonblock = nonblock(fd);
ptrlen senddata;
do {
senddata = bufchain_prefix(chain);
ret = write(fd, senddata.ptr, senddata.len);
if (ret > 0)
bufchain_consume(chain, ret);
} while (ret == senddata.len && bufchain_size(chain) != 0);
if (!prev_nonblock)
no_nonblock(fd);
if (ret < 0 && errno != EAGAIN) {
perror(is_stderr ? "stderr: write" : "stdout: write");
exit(1);
}
}
if (outgoingeof == EOF_PENDING && bufchain_size(&stdout_data) == 0) {
close(STDOUT_FILENO);
outgoingeof = EOF_SENT;
}
return bufchain_size(&stdout_data) + bufchain_size(&stderr_data);
}
static size_t plink_output(
Seat *seat, bool is_stderr, const void *data, size_t len)
{
assert(is_stderr || outgoingeof == EOF_NO);
BinarySink *bs = is_stderr ? stderr_bs : stdout_bs;
put_data(bs, data, len);
return try_output(is_stderr);
}
static bool plink_eof(Seat *seat)
{
assert(outgoingeof == EOF_NO);
outgoingeof = EOF_PENDING;
try_output(false);
return false; /* do not respond to incoming EOF with outgoing */
}
static int plink_get_userpass_input(Seat *seat, prompts_t *p, bufchain *input)
{
int ret;
ret = cmdline_get_passwd_input(p);
if (ret == -1)
ret = console_get_userpass_input(p);
return ret;
}
static const SeatVtable plink_seat_vt = {
plink_output,
plink_eof,
plink_get_userpass_input,
nullseat_notify_remote_exit,
console_connection_fatal,
nullseat_update_specials_menu,
plink_get_ttymode,
nullseat_set_busy_status,
console_verify_ssh_host_key,
console_confirm_weak_crypto_primitive,
console_confirm_weak_cached_hostkey,
nullseat_is_never_utf8,
plink_echoedit_update,
nullseat_get_x_display,
nullseat_get_windowid,
nullseat_get_window_pixel_size,
console_stripctrl_new,
};
static Seat plink_seat[1] = {{ &plink_seat_vt }};
/*
* Handle data from a local tty in PARMRK format.
*/
static void from_tty(void *vbuf, unsigned len)
{
char *p, *q, *end, *buf = vbuf;
static enum {NORMAL, FF, FF00} state = NORMAL;
p = buf; end = buf + len;
while (p < end) {
switch (state) {
case NORMAL:
if (*p == '\xff') {
p++;
state = FF;
} else {
q = memchr(p, '\xff', end - p);
if (q == NULL) q = end;
backend_send(backend, p, q - p);
p = q;
}
break;
case FF:
if (*p == '\xff') {
backend_send(backend, p, 1);
p++;
state = NORMAL;
} else if (*p == '\0') {
p++;
state = FF00;
} else abort();
break;
case FF00:
if (*p == '\0') {
backend_special(backend, SS_BRK, 0);
} else {
/*
* Pretend that PARMRK wasn't set. This involves
* faking what INPCK and IGNPAR would have done if
* we hadn't overridden them. Unfortunately, we
* can't do this entirely correctly because INPCK
* distinguishes between framing and parity
* errors, but PARMRK format represents both in
* the same way. We assume that parity errors are
* more common than framing errors, and hence
* treat all input errors as being subject to
* INPCK.
*/
if (orig_termios.c_iflag & INPCK) {
/* If IGNPAR is set, we throw away the character. */
if (!(orig_termios.c_iflag & IGNPAR)) {
/* PE/FE get passed on as NUL. */
*p = 0;
backend_send(backend, p, 1);
}
} else {
/* INPCK not set. Assume we got a parity error. */
backend_send(backend, p, 1);
}
}
p++;
state = NORMAL;
}
}
}
int signalpipe[2];
void sigwinch(int signum)
{
if (write(signalpipe[1], "x", 1) <= 0)
/* not much we can do about it */;
}
/*
* In Plink our selects are synchronous, so these functions are
* empty stubs.
*/
uxsel_id *uxsel_input_add(int fd, int rwx) { return NULL; }
void uxsel_input_remove(uxsel_id *id) { }
/*
* Short description of parameters.
*/
static void usage(void)
{
printf("Plink: command-line connection utility\n");
printf("%s\n", ver);
printf("Usage: plink [options] [user@]host [command]\n");
printf(" (\"host\" can also be a PuTTY saved session name)\n");
printf("Options:\n");
printf(" -V print version information and exit\n");
printf(" -pgpfp print PGP key fingerprints and exit\n");
printf(" -v show verbose messages\n");
printf(" -load sessname Load settings from saved session\n");
printf(" -ssh -telnet -rlogin -raw -serial\n");
printf(" force use of a particular protocol\n");
printf(" -P port connect to specified port\n");
printf(" -l user connect with specified username\n");
printf(" -batch disable all interactive prompts\n");
printf(" -proxycmd command\n");
printf(" use 'command' as local proxy\n");
printf(" -sercfg configuration-string (e.g. 19200,8,n,1,X)\n");
printf(" Specify the serial configuration (serial only)\n");
printf("The following options only apply to SSH connections:\n");
printf(" -pw passw login with specified password\n");
printf(" -D [listen-IP:]listen-port\n");
printf(" Dynamic SOCKS-based port forwarding\n");
printf(" -L [listen-IP:]listen-port:host:port\n");
printf(" Forward local port to remote address\n");
printf(" -R [listen-IP:]listen-port:host:port\n");
printf(" Forward remote port to local address\n");
printf(" -X -x enable / disable X11 forwarding\n");
printf(" -A -a enable / disable agent forwarding\n");
printf(" -t -T enable / disable pty allocation\n");
printf(" -1 -2 force use of particular protocol version\n");
printf(" -4 -6 force use of IPv4 or IPv6\n");
printf(" -C enable compression\n");
printf(" -i key private key file for user authentication\n");
printf(" -noagent disable use of Pageant\n");
printf(" -agent enable use of Pageant\n");
printf(" -noshare disable use of connection sharing\n");
printf(" -share enable use of connection sharing\n");
printf(" -hostkey aa:bb:cc:...\n");
printf(" manually specify a host key (may be repeated)\n");
printf(" -sanitise-stderr, -sanitise-stdout, "
"-no-sanitise-stderr, -no-sanitise-stdout\n");
printf(" do/don't strip control chars from standard "
"output/error\n");
printf(" -m file read remote command(s) from file\n");
printf(" -s remote command is an SSH subsystem (SSH-2 only)\n");
printf(" -N don't start a shell/command (SSH-2 only)\n");
printf(" -nc host:port\n");
printf(" open tunnel in place of session (SSH-2 only)\n");
printf(" -sshlog file\n");
printf(" -sshrawlog file\n");
printf(" log protocol details to a file\n");
printf(" -shareexists\n");
printf(" test whether a connection-sharing upstream exists\n");
exit(1);
}
static void version(void)
{
char *buildinfo_text = buildinfo("\n");
printf("plink: %s\n%s\n", ver, buildinfo_text);
sfree(buildinfo_text);
exit(0);
}
void frontend_net_error_pending(void) {}
const bool share_can_be_downstream = true;
const bool share_can_be_upstream = true;
const bool buildinfo_gtk_relevant = false;
int main(int argc, char **argv)
{
bool sending;
int *fdlist;
int fd;
int i, fdstate;
size_t fdsize;
int exitcode;
bool errors;
enum TriState sanitise_stdout = AUTO, sanitise_stderr = AUTO;
bool use_subsystem = false;
bool just_test_share_exists = false;
unsigned long now;
struct winsize size;
const struct BackendVtable *backvt;
fdlist = NULL;
fdsize = 0;
/*
* Initialise port and protocol to sensible defaults. (These
* will be overridden by more or less anything.)
*/
default_protocol = PROT_SSH;
default_port = 22;
bufchain_init(&stdout_data);
bufchain_init(&stderr_data);
bufchain_sink_init(&stdout_bcs, &stdout_data);
bufchain_sink_init(&stderr_bcs, &stderr_data);
stdout_bs = BinarySink_UPCAST(&stdout_bcs);
stderr_bs = BinarySink_UPCAST(&stderr_bcs);
outgoingeof = EOF_NO;
flags = FLAG_STDERR_TTY;
cmdline_tooltype |=
(TOOLTYPE_HOST_ARG |
TOOLTYPE_HOST_ARG_CAN_BE_SESSION |
TOOLTYPE_HOST_ARG_PROTOCOL_PREFIX |
TOOLTYPE_HOST_ARG_FROM_LAUNCHABLE_LOAD);
stderr_tty_init();
/*
* Process the command line.
*/
conf = conf_new();
do_defaults(NULL, conf);
loaded_session = false;
default_protocol = conf_get_int(conf, CONF_protocol);
default_port = conf_get_int(conf, CONF_port);
errors = false;
{
/*
* Override the default protocol if PLINK_PROTOCOL is set.
*/
char *p = getenv("PLINK_PROTOCOL");
if (p) {
const struct BackendVtable *vt = backend_vt_from_name(p);
if (vt) {
default_protocol = vt->protocol;
default_port = vt->default_port;
conf_set_int(conf, CONF_protocol, default_protocol);
conf_set_int(conf, CONF_port, default_port);
}
}
}
while (--argc) {
char *p = *++argv;
int ret = cmdline_process_param(p, (argc > 1 ? argv[1] : NULL),
1, conf);
if (ret == -2) {
fprintf(stderr,
"plink: option \"%s\" requires an argument\n", p);
errors = true;
} else if (ret == 2) {
--argc, ++argv;
} else if (ret == 1) {
continue;
} else if (!strcmp(p, "-batch")) {
console_batch_mode = true;
} else if (!strcmp(p, "-s")) {
/* Save status to write to conf later. */
use_subsystem = true;
} else if (!strcmp(p, "-V") || !strcmp(p, "--version")) {
version();
} else if (!strcmp(p, "--help")) {
usage();
exit(0);
} else if (!strcmp(p, "-pgpfp")) {
pgp_fingerprints();
exit(1);
} else if (!strcmp(p, "-o")) {
if (argc <= 1) {
fprintf(stderr,
"plink: option \"-o\" requires an argument\n");
errors = true;
} else {
--argc;
provide_xrm_string(*++argv);
}
} else if (!strcmp(p, "-shareexists")) {
just_test_share_exists = true;
} else if (!strcmp(p, "-fuzznet")) {
conf_set_int(conf, CONF_proxy_type, PROXY_FUZZ);
conf_set_str(conf, CONF_proxy_telnet_command, "%host");
} else if (!strcmp(p, "-sanitise-stdout") ||
!strcmp(p, "-sanitize-stdout")) {
sanitise_stdout = FORCE_ON;
} else if (!strcmp(p, "-no-sanitise-stdout") ||
!strcmp(p, "-no-sanitize-stdout")) {
sanitise_stdout = FORCE_OFF;
} else if (!strcmp(p, "-sanitise-stderr") ||
!strcmp(p, "-sanitize-stderr")) {
sanitise_stderr = FORCE_ON;
} else if (!strcmp(p, "-no-sanitise-stderr") ||
!strcmp(p, "-no-sanitize-stderr")) {
sanitise_stderr = FORCE_OFF;
} else if (*p != '-') {
strbuf *cmdbuf = strbuf_new();
while (argc > 0) {
if (cmdbuf->len > 0)
put_byte(cmdbuf, ' '); /* add space separator */
put_datapl(cmdbuf, ptrlen_from_asciz(p));
if (--argc > 0)
p = *++argv;
}
conf_set_str(conf, CONF_remote_cmd, cmdbuf->s);
conf_set_str(conf, CONF_remote_cmd2, "");
conf_set_bool(conf, CONF_nopty, true); /* command => no tty */
strbuf_free(cmdbuf);
break; /* done with cmdline */
} else {
fprintf(stderr, "plink: unknown option \"%s\"\n", p);
errors = true;
}
}
if (errors)
return 1;
if (!cmdline_host_ok(conf)) {
usage();
}
prepare_session(conf);
/*
* Perform command-line overrides on session configuration.
*/
cmdline_run_saved(conf);
/*
* If we have no better ideas for the remote username, use the local
* one, as 'ssh' does.
*/
if (conf_get_str(conf, CONF_username)[0] == '\0') {
char *user = get_username();
if (user) {
conf_set_str(conf, CONF_username, user);
sfree(user);
}
}
/*
* Apply subsystem status.
*/
if (use_subsystem)
conf_set_bool(conf, CONF_ssh_subsys, true);
if (!*conf_get_str(conf, CONF_remote_cmd) &&
!*conf_get_str(conf, CONF_remote_cmd2) &&
!*conf_get_str(conf, CONF_ssh_nc_host))
flags |= FLAG_INTERACTIVE;
/*
* Select protocol. This is farmed out into a table in a
* separate file to enable an ssh-free variant.
*/
backvt = backend_vt_from_proto(conf_get_int(conf, CONF_protocol));
if (!backvt) {
fprintf(stderr,
"Internal fault: Unsupported protocol found\n");
return 1;
}
/*
* Block SIGPIPE, so that we'll get EPIPE individually on
* particular network connections that go wrong.
*/
putty_signal(SIGPIPE, SIG_IGN);
/*
* Set up the pipe we'll use to tell us about SIGWINCH.
*/
if (pipe(signalpipe) < 0) {
perror("pipe");
exit(1);
}
/* We don't want the signal handler to block if the pipe's full. */
nonblock(signalpipe[0]);
nonblock(signalpipe[1]);
cloexec(signalpipe[0]);
cloexec(signalpipe[1]);
putty_signal(SIGWINCH, sigwinch);
/*
* Now that we've got the SIGWINCH handler installed, try to find
* out the initial terminal size.
*/
if (ioctl(STDIN_FILENO, TIOCGWINSZ, &size) >= 0) {
conf_set_int(conf, CONF_width, size.ws_col);
conf_set_int(conf, CONF_height, size.ws_row);
}
/*
* Decide whether to sanitise control sequences out of standard
* output and standard error.
*
* If we weren't given a command-line override, we do this if (a)
* the fd in question is pointing at a terminal, and (b) we aren't
* trying to allocate a terminal as part of the session.
*
* (Rationale: the risk of control sequences is that they cause
* confusion when sent to a local terminal, so if there isn't one,
* no problem. Also, if we allocate a remote terminal, then we
* sent a terminal type, i.e. we told it what kind of escape
* sequences we _like_, i.e. we were expecting to receive some.)
*/
if (sanitise_stdout == FORCE_ON ||
(sanitise_stdout == AUTO && isatty(STDOUT_FILENO) &&
conf_get_bool(conf, CONF_nopty))) {
stdout_scc = stripctrl_new(stdout_bs, true, L'\0');
stdout_bs = BinarySink_UPCAST(stdout_scc);
}
if (sanitise_stderr == FORCE_ON ||
(sanitise_stderr == AUTO && isatty(STDERR_FILENO) &&
conf_get_bool(conf, CONF_nopty))) {
stderr_scc = stripctrl_new(stderr_bs, true, L'\0');
stderr_bs = BinarySink_UPCAST(stderr_scc);
}
sk_init();
uxsel_init();
/*
* Plink doesn't provide any way to add forwardings after the
* connection is set up, so if there are none now, we can safely set
* the "simple" flag.
*/
if (conf_get_int(conf, CONF_protocol) == PROT_SSH &&
!conf_get_bool(conf, CONF_x11_forward) &&
!conf_get_bool(conf, CONF_agentfwd) &&
!conf_get_str_nthstrkey(conf, CONF_portfwd, 0))
conf_set_bool(conf, CONF_ssh_simple, true);
if (just_test_share_exists) {
if (!backvt->test_for_upstream) {
fprintf(stderr, "Connection sharing not supported for connection "
"type '%s'\n", backvt->name);
return 1;
}
if (backvt->test_for_upstream(conf_get_str(conf, CONF_host),
conf_get_int(conf, CONF_port), conf))
return 0;
else
return 1;
}
/*
* Start up the connection.
*/
logctx = log_init(default_logpolicy, conf);
{
const char *error;
char *realhost;
/* nodelay is only useful if stdin is a terminal device */
bool nodelay = conf_get_bool(conf, CONF_tcp_nodelay) && isatty(0);
/* This is a good place for a fuzzer to fork us. */
#ifdef __AFL_HAVE_MANUAL_CONTROL
__AFL_INIT();
#endif
error = backend_init(backvt, plink_seat, &backend, logctx, conf,
conf_get_str(conf, CONF_host),
conf_get_int(conf, CONF_port),
&realhost, nodelay,
conf_get_bool(conf, CONF_tcp_keepalives));
if (error) {
fprintf(stderr, "Unable to open connection:\n%s\n", error);
return 1;
}
ldisc_create(conf, NULL, backend, plink_seat);
sfree(realhost);
}
/*
* Set up the initial console mode. We don't care if this call
* fails, because we know we aren't necessarily running in a
* console.
*/
local_tty = (tcgetattr(STDIN_FILENO, &orig_termios) == 0);
atexit(cleanup_termios);
seat_echoedit_update(plink_seat, 1, 1);
sending = false;
now = GETTICKCOUNT();
pollwrapper *pw = pollwrap_new();
while (1) {
int rwx;
int ret;
unsigned long next;
pollwrap_clear(pw);
pollwrap_add_fd_rwx(pw, signalpipe[0], SELECT_R);
if (!sending &&
backend_connected(backend) &&
backend_sendok(backend) &&
backend_sendbuffer(backend) < MAX_STDIN_BACKLOG) {
/* If we're OK to send, then try to read from stdin. */
pollwrap_add_fd_rwx(pw, STDIN_FILENO, SELECT_R);
}
if (bufchain_size(&stdout_data) > 0) {
/* If we have data for stdout, try to write to stdout. */
pollwrap_add_fd_rwx(pw, STDOUT_FILENO, SELECT_W);
}
if (bufchain_size(&stderr_data) > 0) {
/* If we have data for stderr, try to write to stderr. */
pollwrap_add_fd_rwx(pw, STDERR_FILENO, SELECT_W);
}
/* Count the currently active fds. */
i = 0;
for (fd = first_fd(&fdstate, &rwx); fd >= 0;
fd = next_fd(&fdstate, &rwx)) i++;
/* Expand the fdlist buffer if necessary. */
sgrowarray(fdlist, fdsize, i);
/*
* Add all currently open fds to pw, and store them in fdlist
* as well.
*/
int fdcount = 0;
for (fd = first_fd(&fdstate, &rwx); fd >= 0;
fd = next_fd(&fdstate, &rwx)) {
fdlist[fdcount++] = fd;
pollwrap_add_fd_rwx(pw, fd, rwx);
}
if (toplevel_callback_pending()) {
ret = pollwrap_poll_instant(pw);
} else if (run_timers(now, &next)) {
do {
unsigned long then;
long ticks;
then = now;
now = GETTICKCOUNT();
if (now - then > next - then)
ticks = 0;
else
ticks = next - now;
bool overflow = false;
if (ticks > INT_MAX) {
ticks = INT_MAX;
overflow = true;
}
ret = pollwrap_poll_timeout(pw, ticks);
if (ret == 0 && !overflow)
now = next;
else
now = GETTICKCOUNT();
} while (ret < 0 && errno == EINTR);
} else {
ret = pollwrap_poll_endless(pw);
}
if (ret < 0 && errno == EINTR)
continue;
if (ret < 0) {
perror("poll");
exit(1);
}
for (i = 0; i < fdcount; i++) {
fd = fdlist[i];
int rwx = pollwrap_get_fd_rwx(pw, fd);
/*
* We must process exceptional notifications before
* ordinary readability ones, or we may go straight
* past the urgent marker.
*/
if (rwx & SELECT_X)
select_result(fd, SELECT_X);
if (rwx & SELECT_R)
select_result(fd, SELECT_R);
if (rwx & SELECT_W)
select_result(fd, SELECT_W);
}
if (pollwrap_check_fd_rwx(pw, signalpipe[0], SELECT_R)) {
char c[1];
struct winsize size;
if (read(signalpipe[0], c, 1) <= 0)
/* ignore error */;
/* ignore its value; it'll be `x' */
if (ioctl(STDIN_FILENO, TIOCGWINSZ, (void *)&size) >= 0)
backend_size(backend, size.ws_col, size.ws_row);
}
if (pollwrap_check_fd_rwx(pw, STDIN_FILENO, SELECT_R)) {
char buf[4096];
int ret;
if (backend_connected(backend)) {
ret = read(STDIN_FILENO, buf, sizeof(buf));
noise_ultralight(NOISE_SOURCE_IOLEN, ret);
if (ret < 0) {
perror("stdin: read");
exit(1);
} else if (ret == 0) {
backend_special(backend, SS_EOF, 0);
sending = false; /* send nothing further after this */
} else {
if (local_tty)
from_tty(buf, ret);
else
backend_send(backend, buf, ret);
}
}
}
if (pollwrap_check_fd_rwx(pw, STDOUT_FILENO, SELECT_W)) {
backend_unthrottle(backend, try_output(false));
}
if (pollwrap_check_fd_rwx(pw, STDERR_FILENO, SELECT_W)) {
backend_unthrottle(backend, try_output(true));
}
run_toplevel_callbacks();
if (!backend_connected(backend) &&
bufchain_size(&stdout_data) == 0 &&
bufchain_size(&stderr_data) == 0)
break; /* we closed the connection */
}
exitcode = backend_exitcode(backend);
if (exitcode < 0) {
fprintf(stderr, "Remote process exit code unavailable\n");
exitcode = 1; /* this is an error condition */
}
cleanup_exit(exitcode);
return exitcode; /* shouldn't happen, but placates gcc */
}
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