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putty-source/unix/uxplink.c
Jacob Nevins 8719f92c14 Revamp SSH authentication code so that user interaction is more 
abstracted out; replace loops structured around a single interaction
per loop with less tortuous code (fixes: `ki-multiprompt-crash',
`ssh1-bad-passphrase-crash'; makes `ssh2-password-expiry' and
`proxy-password-prompt' easier).

The new interaction abstraction has a lot of fields that are unused in
the current code (things like window captions); this is groundwork for
`gui-auth'. However, ssh.c still writes directly to stderr; that may
want to be fixed.

In the GUI apps, user interaction is moved to terminal.c. This should
make it easier to fix things like UTF-8 username entry, although I
haven't attempted to do so. Also, control character filtering can be
tailored to be appropriate for individual front-ends; so far I don't
promise anything other than not having made it any worse.

I've tried to test this fairly exhaustively (although Mac stuff is
untested, as usual). It all seems to basically work, but I bet there
are new bugs. (One I know about is that you can no longer make the
PuTTY window go away with a ^D at the password prompt; this should be
fixed.)

[originally from svn r6437]
[this svn revision also touched putty-wishlist]
2005-10-30 20:24:09 +00:00

1055 lines
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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>
#ifndef HAVE_NO_SYS_SELECT_H
#include <sys/select.h>
#endif
#define PUTTY_DO_GLOBALS /* actually _define_ globals */
#include "putty.h"
#include "storage.h"
#include "tree234.h"
#define MAX_STDIN_BACKLOG 4096
void fatalbox(char *p, ...)
{
va_list ap;
fprintf(stderr, "FATAL ERROR: ");
va_start(ap, p);
vfprintf(stderr, p, ap);
va_end(ap);
fputc('\n', stderr);
cleanup_exit(1);
}
void modalfatalbox(char *p, ...)
{
va_list ap;
fprintf(stderr, "FATAL ERROR: ");
va_start(ap, p);
vfprintf(stderr, p, ap);
va_end(ap);
fputc('\n', stderr);
cleanup_exit(1);
}
void connection_fatal(void *frontend, char *p, ...)
{
va_list ap;
fprintf(stderr, "FATAL ERROR: ");
va_start(ap, p);
vfprintf(stderr, p, ap);
va_end(ap);
fputc('\n', stderr);
cleanup_exit(1);
}
void cmdline_error(char *p, ...)
{
va_list ap;
fprintf(stderr, "plink: ");
va_start(ap, p);
vfprintf(stderr, p, ap);
va_end(ap);
fputc('\n', stderr);
exit(1);
}
static int local_tty = 0; /* do we have a local tty? */
static struct termios orig_termios;
static Backend *back;
static void *backhandle;
static Config cfg;
/*
* Default settings that are specific to pterm.
*/
char *platform_default_s(const char *name)
{
if (!strcmp(name, "TermType"))
return dupstr(getenv("TERM"));
if (!strcmp(name, "UserName"))
return get_username();
return NULL;
}
int platform_default_i(const char *name, int def)
{
if (!strcmp(name, "TermWidth") ||
!strcmp(name, "TermHeight")) {
struct winsize size;
if (ioctl(0, TIOCGWINSZ, (void *)&size) >= 0)
return (!strcmp(name, "TermWidth") ? size.ws_col : size.ws_row);
}
return def;
}
FontSpec platform_default_fontspec(const char *name)
{
FontSpec ret;
*ret.name = '\0';
return ret;
}
Filename platform_default_filename(const char *name)
{
Filename ret;
if (!strcmp(name, "LogFileName"))
strcpy(ret.path, "putty.log");
else
*ret.path = '\0';
return ret;
}
char *x_get_default(const char *key)
{
return NULL; /* this is a stub */
}
int term_ldisc(Terminal *term, int mode)
{
return FALSE;
}
void ldisc_update(void *frontend, int echo, int 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 ldisc_update(), 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(0, 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 dupprintf("");
#endif
return dupprintf("^<%d>", c);
}
char *get_ttymode(void *frontend, 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) { \
int 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
/* 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(0, TCSANOW, &orig_termios);
}
bufchain stdout_data, stderr_data;
void try_output(int is_stderr)
{
bufchain *chain = (is_stderr ? &stderr_data : &stdout_data);
int fd = (is_stderr ? 2 : 1);
void *senddata;
int sendlen, ret;
if (bufchain_size(chain) == 0)
return;
bufchain_prefix(chain, &senddata, &sendlen);
ret = write(fd, senddata, sendlen);
if (ret > 0)
bufchain_consume(chain, ret);
else if (ret < 0) {
perror(is_stderr ? "stderr: write" : "stdout: write");
exit(1);
}
}
int from_backend(void *frontend_handle, int is_stderr,
const char *data, int len)
{
int osize, esize;
if (is_stderr) {
bufchain_add(&stderr_data, data, len);
try_output(1);
} else {
bufchain_add(&stdout_data, data, len);
try_output(0);
}
osize = bufchain_size(&stdout_data);
esize = bufchain_size(&stderr_data);
return osize + esize;
}
int from_backend_untrusted(void *frontend_handle, const char *data, int len)
{
/*
* No "untrusted" output should get here (the way the code is
* currently, it's all diverted by FLAG_STDERR).
*/
assert(!"Unexpected call to from_backend_untrusted()");
return 0; /* not reached */
}
int get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
{
int ret;
ret = cmdline_get_passwd_input(p, in, inlen);
if (ret == -1)
ret = console_get_userpass_input(p, in, inlen);
return ret;
}
/*
* Handle data from a local tty in PARMRK format.
*/
static void from_tty(void *buf, unsigned len)
{
char *p, *q, *end;
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;
back->send(backhandle, p, q - p);
p = q;
}
break;
case FF:
if (*p == '\xff') {
back->send(backhandle, p, 1);
p++;
state = NORMAL;
} else if (*p == '\0') {
p++;
state = FF00;
} else abort();
break;
case FF00:
if (*p == '\0') {
back->special(backhandle, TS_BRK);
} 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;
back->send(backhandle, p, 1);
}
} else {
/* INPCK not set. Assume we got a parity error. */
back->send(backhandle, p, 1);
}
}
p++;
state = NORMAL;
}
}
}
int signalpipe[2];
void sigwinch(int signum)
{
write(signalpipe[1], "x", 1);
}
/*
* In Plink our selects are synchronous, so these functions are
* empty stubs.
*/
int uxsel_input_add(int fd, int rwx) { return 0; }
void uxsel_input_remove(int id) { }
/*
* Short description of parameters.
*/
static void usage(void)
{
printf("PuTTY Link: 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\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("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 authentication\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");
exit(1);
}
static void version(void)
{
printf("plink: %s\n", ver);
exit(1);
}
int main(int argc, char **argv)
{
int sending;
int portnumber = -1;
int *fdlist;
int fd;
int i, fdcount, fdsize, fdstate;
int connopen;
int exitcode;
int errors;
int use_subsystem = 0;
void *ldisc, *logctx;
long now;
fdlist = NULL;
fdcount = 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;
flags = FLAG_STDERR;
/*
* Process the command line.
*/
do_defaults(NULL, &cfg);
loaded_session = FALSE;
default_protocol = cfg.protocol;
default_port = cfg.port;
errors = 0;
{
/*
* Override the default protocol if PLINK_PROTOCOL is set.
*/
char *p = getenv("PLINK_PROTOCOL");
int i;
if (p) {
for (i = 0; backends[i].backend != NULL; i++) {
if (!strcmp(backends[i].name, p)) {
default_protocol = cfg.protocol = backends[i].protocol;
default_port = cfg.port =
backends[i].backend->default_port;
break;
}
}
}
}
while (--argc) {
char *p = *++argv;
if (*p == '-') {
int ret = cmdline_process_param(p, (argc > 1 ? argv[1] : NULL),
1, &cfg);
if (ret == -2) {
fprintf(stderr,
"plink: option \"%s\" requires an argument\n", p);
errors = 1;
} else if (ret == 2) {
--argc, ++argv;
} else if (ret == 1) {
continue;
} else if (!strcmp(p, "-batch")) {
console_batch_mode = 1;
} else if (!strcmp(p, "-s")) {
/* Save status to write to cfg later. */
use_subsystem = 1;
} else if (!strcmp(p, "-V")) {
version();
} 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 = 1;
} else {
--argc;
provide_xrm_string(*++argv);
}
} else {
fprintf(stderr, "plink: unknown option \"%s\"\n", p);
errors = 1;
}
} else if (*p) {
if (!*cfg.host) {
char *q = p;
do_defaults(NULL, &cfg);
/*
* If the hostname starts with "telnet:", set the
* protocol to Telnet and process the string as a
* Telnet URL.
*/
if (!strncmp(q, "telnet:", 7)) {
char c;
q += 7;
if (q[0] == '/' && q[1] == '/')
q += 2;
cfg.protocol = PROT_TELNET;
p = q;
while (*p && *p != ':' && *p != '/')
p++;
c = *p;
if (*p)
*p++ = '\0';
if (c == ':')
cfg.port = atoi(p);
else
cfg.port = -1;
strncpy(cfg.host, q, sizeof(cfg.host) - 1);
cfg.host[sizeof(cfg.host) - 1] = '\0';
} else {
char *r, *user, *host;
/*
* Before we process the [user@]host string, we
* first check for the presence of a protocol
* prefix (a protocol name followed by ",").
*/
r = strchr(p, ',');
if (r) {
int i, j;
for (i = 0; backends[i].backend != NULL; i++) {
j = strlen(backends[i].name);
if (j == r - p &&
!memcmp(backends[i].name, p, j)) {
default_protocol = cfg.protocol =
backends[i].protocol;
portnumber =
backends[i].backend->default_port;
p = r + 1;
break;
}
}
}
/*
* A nonzero length string followed by an @ is treated
* as a username. (We discount an _initial_ @.) The
* rest of the string (or the whole string if no @)
* is treated as a session name and/or hostname.
*/
r = strrchr(p, '@');
if (r == p)
p++, r = NULL; /* discount initial @ */
if (r) {
*r++ = '\0';
user = p, host = r;
} else {
user = NULL, host = p;
}
/*
* Now attempt to load a saved session with the
* same name as the hostname.
*/
{
Config cfg2;
do_defaults(host, &cfg2);
if (loaded_session || cfg2.host[0] == '\0') {
/* No settings for this host; use defaults */
/* (or session was already loaded with -load) */
strncpy(cfg.host, host, sizeof(cfg.host) - 1);
cfg.host[sizeof(cfg.host) - 1] = '\0';
cfg.port = default_port;
} else {
cfg = cfg2;
}
}
if (user) {
/* Patch in specified username. */
strncpy(cfg.username, user,
sizeof(cfg.username) - 1);
cfg.username[sizeof(cfg.username) - 1] = '\0';
}
}
} else {
char *command;
int cmdlen, cmdsize;
cmdlen = cmdsize = 0;
command = NULL;
while (argc) {
while (*p) {
if (cmdlen >= cmdsize) {
cmdsize = cmdlen + 512;
command = sresize(command, cmdsize, char);
}
command[cmdlen++]=*p++;
}
if (cmdlen >= cmdsize) {
cmdsize = cmdlen + 512;
command = sresize(command, cmdsize, char);
}
command[cmdlen++]=' '; /* always add trailing space */
if (--argc) p = *++argv;
}
if (cmdlen) command[--cmdlen]='\0';
/* change trailing blank to NUL */
cfg.remote_cmd_ptr = command;
cfg.remote_cmd_ptr2 = NULL;
cfg.nopty = TRUE; /* command => no terminal */
break; /* done with cmdline */
}
}
}
if (errors)
return 1;
if (!*cfg.host) {
usage();
}
/*
* Trim leading whitespace off the hostname if it's there.
*/
{
int space = strspn(cfg.host, " \t");
memmove(cfg.host, cfg.host+space, 1+strlen(cfg.host)-space);
}
/* See if host is of the form user@host */
if (cfg.host[0] != '\0') {
char *atsign = strrchr(cfg.host, '@');
/* Make sure we're not overflowing the user field */
if (atsign) {
if (atsign - cfg.host < sizeof cfg.username) {
strncpy(cfg.username, cfg.host, atsign - cfg.host);
cfg.username[atsign - cfg.host] = '\0';
}
memmove(cfg.host, atsign + 1, 1 + strlen(atsign + 1));
}
}
/*
* Perform command-line overrides on session configuration.
*/
cmdline_run_saved(&cfg);
/*
* Apply subsystem status.
*/
if (use_subsystem)
cfg.ssh_subsys = TRUE;
/*
* Trim a colon suffix off the hostname if it's there.
*/
cfg.host[strcspn(cfg.host, ":")] = '\0';
/*
* Remove any remaining whitespace from the hostname.
*/
{
int p1 = 0, p2 = 0;
while (cfg.host[p2] != '\0') {
if (cfg.host[p2] != ' ' && cfg.host[p2] != '\t') {
cfg.host[p1] = cfg.host[p2];
p1++;
}
p2++;
}
cfg.host[p1] = '\0';
}
if (!cfg.remote_cmd_ptr && !*cfg.remote_cmd)
flags |= FLAG_INTERACTIVE;
/*
* Select protocol. This is farmed out into a table in a
* separate file to enable an ssh-free variant.
*/
{
int i;
back = NULL;
for (i = 0; backends[i].backend != NULL; i++)
if (backends[i].protocol == cfg.protocol) {
back = backends[i].backend;
break;
}
if (back == NULL) {
fprintf(stderr,
"Internal fault: Unsupported protocol found\n");
return 1;
}
}
/*
* Select port.
*/
if (portnumber != -1)
cfg.port = portnumber;
/*
* Set up the pipe we'll use to tell us about SIGWINCH.
*/
if (pipe(signalpipe) < 0) {
perror("pipe");
exit(1);
}
putty_signal(SIGWINCH, sigwinch);
sk_init();
uxsel_init();
/*
* Start up the connection.
*/
logctx = log_init(NULL, &cfg);
console_provide_logctx(logctx);
{
const char *error;
char *realhost;
/* nodelay is only useful if stdin is a terminal device */
int nodelay = cfg.tcp_nodelay && isatty(0);
error = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port,
&realhost, nodelay, cfg.tcp_keepalives);
if (error) {
fprintf(stderr, "Unable to open connection:\n%s\n", error);
return 1;
}
back->provide_logctx(backhandle, logctx);
ldisc = ldisc_create(&cfg, NULL, back, backhandle, NULL);
sfree(realhost);
}
connopen = 1;
/*
* 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(0, &orig_termios) == 0);
atexit(cleanup_termios);
ldisc_update(NULL, 1, 1);
sending = FALSE;
now = GETTICKCOUNT();
while (1) {
fd_set rset, wset, xset;
int maxfd;
int rwx;
int ret;
FD_ZERO(&rset);
FD_ZERO(&wset);
FD_ZERO(&xset);
maxfd = 0;
FD_SET_MAX(signalpipe[0], maxfd, rset);
if (connopen && !sending &&
back->socket(backhandle) != NULL &&
back->sendok(backhandle) &&
back->sendbuffer(backhandle) < MAX_STDIN_BACKLOG) {
/* If we're OK to send, then try to read from stdin. */
FD_SET_MAX(0, maxfd, rset);
}
if (bufchain_size(&stdout_data) > 0) {
/* If we have data for stdout, try to write to stdout. */
FD_SET_MAX(1, maxfd, wset);
}
if (bufchain_size(&stderr_data) > 0) {
/* If we have data for stderr, try to write to stderr. */
FD_SET_MAX(2, maxfd, wset);
}
/* 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. */
if (i > fdsize) {
fdsize = i + 16;
fdlist = sresize(fdlist, fdsize, int);
}
/*
* Add all currently open fds to the select sets, and store
* them in fdlist as well.
*/
fdcount = 0;
for (fd = first_fd(&fdstate, &rwx); fd >= 0;
fd = next_fd(&fdstate, &rwx)) {
fdlist[fdcount++] = fd;
if (rwx & 1)
FD_SET_MAX(fd, maxfd, rset);
if (rwx & 2)
FD_SET_MAX(fd, maxfd, wset);
if (rwx & 4)
FD_SET_MAX(fd, maxfd, xset);
}
do {
long next, ticks;
struct timeval tv, *ptv;
if (run_timers(now, &next)) {
ticks = next - GETTICKCOUNT();
if (ticks < 0) ticks = 0; /* just in case */
tv.tv_sec = ticks / 1000;
tv.tv_usec = ticks % 1000 * 1000;
ptv = &tv;
} else {
ptv = NULL;
}
ret = select(maxfd, &rset, &wset, &xset, ptv);
if (ret == 0)
now = next;
else {
long newnow = GETTICKCOUNT();
/*
* Check to see whether the system clock has
* changed massively during the select.
*/
if (newnow - now < 0 || newnow - now > next - now) {
/*
* If so, look at the elapsed time in the
* select and use it to compute a new
* tickcount_offset.
*/
long othernow = now + tv.tv_sec * 1000 + tv.tv_usec / 1000;
/* So we'd like GETTICKCOUNT to have returned othernow,
* but instead it return newnow. Hence ... */
tickcount_offset += othernow - newnow;
now = othernow;
} else {
now = newnow;
}
}
} while (ret < 0 && errno == EINTR);
if (ret < 0) {
perror("select");
exit(1);
}
for (i = 0; i < fdcount; i++) {
fd = fdlist[i];
/*
* We must process exceptional notifications before
* ordinary readability ones, or we may go straight
* past the urgent marker.
*/
if (FD_ISSET(fd, &xset))
select_result(fd, 4);
if (FD_ISSET(fd, &rset))
select_result(fd, 1);
if (FD_ISSET(fd, &wset))
select_result(fd, 2);
}
if (FD_ISSET(signalpipe[0], &rset)) {
char c[1];
struct winsize size;
read(signalpipe[0], c, 1); /* ignore its value; it'll be `x' */
if (ioctl(0, TIOCGWINSZ, (void *)&size) >= 0)
back->size(backhandle, size.ws_col, size.ws_row);
}
if (FD_ISSET(0, &rset)) {
char buf[4096];
int ret;
if (connopen && back->socket(backhandle) != NULL) {
ret = read(0, buf, sizeof(buf));
if (ret < 0) {
perror("stdin: read");
exit(1);
} else if (ret == 0) {
back->special(backhandle, TS_EOF);
sending = FALSE; /* send nothing further after this */
} else {
if (local_tty)
from_tty(buf, ret);
else
back->send(backhandle, buf, ret);
}
}
}
if (FD_ISSET(1, &wset)) {
try_output(0);
}
if (FD_ISSET(2, &wset)) {
try_output(1);
}
if ((!connopen || back->socket(backhandle) == NULL) &&
bufchain_size(&stdout_data) == 0 &&
bufchain_size(&stderr_data) == 0)
break; /* we closed the connection */
}
exitcode = back->exitcode(backhandle);
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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