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mirror of https://git.tartarus.org/simon/putty.git synced 2025-03-15 03:23:02 -05:00
putty-source/rlogin.c
Simon Tatham ad0c502cef Refactor the LogContext type.
LogContext is now the owner of the logevent() function that back ends
and so forth are constantly calling. Previously, logevent was owned by
the Frontend, which would store the message into its list for the GUI
Event Log dialog (or print it to standard error, or whatever) and then
pass it _back_ to LogContext to write to the currently open log file.
Now it's the other way round: LogContext gets the message from the
back end first, writes it to its log file if it feels so inclined, and
communicates it back to the front end.

This means that lots of parts of the back end system no longer need to
have a pointer to a full-on Frontend; the only thing they needed it
for was logging, so now they just have a LogContext (which many of
them had to have anyway, e.g. for logging SSH packets or session
traffic).

LogContext itself also doesn't get a full Frontend pointer any more:
it now talks back to the front end via a little vtable of its own
called LogPolicy, which contains the method that passes Event Log
entries through, the old askappend() function that decides whether to
truncate a pre-existing log file, and an emergency function for
printing an especially prominent message if the log file can't be
created. One minor nice effect of this is that console and GUI apps
can implement that last function subtly differently, so that Unix
console apps can write it with a plain \n instead of the \r\n
(harmless but inelegant) that the old centralised implementation
generated.

One other consequence of this is that the LogContext has to be
provided to backend_init() so that it's available to backends from the
instant of creation, rather than being provided via a separate API
call a couple of function calls later, because backends have typically
started doing things that need logging (like making network
connections) before the call to backend_provide_logctx. Fortunately,
there's no case in the whole code base where we don't already have
logctx by the time we make a backend (so I don't actually remember why
I ever delayed providing one). So that shortens the backend API by one
function, which is always nice.

While I'm tidying up, I've also moved the printf-style logeventf() and
the handy logevent_and_free() into logging.c, instead of having copies
of them scattered around other places. This has also let me remove
some stub functions from a couple of outlying applications like
Pageant. Finally, I've removed the pointless "_tag" at the end of
LogContext's official struct name.
2018-10-10 21:50:50 +01:00

419 lines
10 KiB
C

/*
* Rlogin backend.
*/
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <ctype.h>
#include "putty.h"
#define RLOGIN_MAX_BACKLOG 4096
typedef struct Rlogin Rlogin;
struct Rlogin {
Socket *s;
int closed_on_socket_error;
int bufsize;
int firstbyte;
int cansize;
int term_width, term_height;
Frontend *frontend;
LogContext *logctx;
Conf *conf;
/* In case we need to read a username from the terminal before starting */
prompts_t *prompt;
Plug plug;
Backend backend;
};
static void c_write(Rlogin *rlogin, const void *buf, int len)
{
int backlog = from_backend(rlogin->frontend, 0, buf, len);
sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
}
static void rlogin_log(Plug *plug, int type, SockAddr *addr, int port,
const char *error_msg, int error_code)
{
Rlogin *rlogin = container_of(plug, Rlogin, plug);
backend_socket_log(rlogin->frontend, rlogin->logctx, type, addr, port,
error_msg, error_code,
rlogin->conf, !rlogin->firstbyte);
}
static void rlogin_closing(Plug *plug, const char *error_msg, int error_code,
int calling_back)
{
Rlogin *rlogin = container_of(plug, Rlogin, plug);
/*
* We don't implement independent EOF in each direction for Telnet
* connections; as soon as we get word that the remote side has
* sent us EOF, we wind up the whole connection.
*/
if (rlogin->s) {
sk_close(rlogin->s);
rlogin->s = NULL;
if (error_msg)
rlogin->closed_on_socket_error = TRUE;
notify_remote_exit(rlogin->frontend);
}
if (error_msg) {
/* A socket error has occurred. */
logevent(rlogin->logctx, error_msg);
connection_fatal(rlogin->frontend, "%s", error_msg);
} /* Otherwise, the remote side closed the connection normally. */
}
static void rlogin_receive(Plug *plug, int urgent, char *data, int len)
{
Rlogin *rlogin = container_of(plug, Rlogin, plug);
if (urgent == 2) {
char c;
c = *data++;
len--;
if (c == '\x80') {
rlogin->cansize = 1;
backend_size(&rlogin->backend,
rlogin->term_width, rlogin->term_height);
}
/*
* We should flush everything (aka Telnet SYNCH) if we see
* 0x02, and we should turn off and on _local_ flow control
* on 0x10 and 0x20 respectively. I'm not convinced it's
* worth it...
*/
} else {
/*
* Main rlogin protocol. This is really simple: the first
* byte is expected to be NULL and is ignored, and the rest
* is printed.
*/
if (rlogin->firstbyte) {
if (data[0] == '\0') {
data++;
len--;
}
rlogin->firstbyte = 0;
}
if (len > 0)
c_write(rlogin, data, len);
}
}
static void rlogin_sent(Plug *plug, int bufsize)
{
Rlogin *rlogin = container_of(plug, Rlogin, plug);
rlogin->bufsize = bufsize;
}
static void rlogin_startup(Rlogin *rlogin, const char *ruser)
{
char z = 0;
char *p;
sk_write(rlogin->s, &z, 1);
p = conf_get_str(rlogin->conf, CONF_localusername);
sk_write(rlogin->s, p, strlen(p));
sk_write(rlogin->s, &z, 1);
sk_write(rlogin->s, ruser, strlen(ruser));
sk_write(rlogin->s, &z, 1);
p = conf_get_str(rlogin->conf, CONF_termtype);
sk_write(rlogin->s, p, strlen(p));
sk_write(rlogin->s, "/", 1);
p = conf_get_str(rlogin->conf, CONF_termspeed);
sk_write(rlogin->s, p, strspn(p, "0123456789"));
rlogin->bufsize = sk_write(rlogin->s, &z, 1);
rlogin->prompt = NULL;
}
static const PlugVtable Rlogin_plugvt = {
rlogin_log,
rlogin_closing,
rlogin_receive,
rlogin_sent
};
/*
* Called to set up the rlogin connection.
*
* Returns an error message, or NULL on success.
*
* Also places the canonical host name into `realhost'. It must be
* freed by the caller.
*/
static const char *rlogin_init(Frontend *frontend, Backend **backend_handle,
LogContext *logctx, Conf *conf,
const char *host, int port, char **realhost,
int nodelay, int keepalive)
{
SockAddr *addr;
const char *err;
Rlogin *rlogin;
char *ruser;
int addressfamily;
char *loghost;
rlogin = snew(Rlogin);
rlogin->plug.vt = &Rlogin_plugvt;
rlogin->backend.vt = &rlogin_backend;
rlogin->s = NULL;
rlogin->closed_on_socket_error = FALSE;
rlogin->frontend = frontend;
rlogin->logctx = logctx;
rlogin->term_width = conf_get_int(conf, CONF_width);
rlogin->term_height = conf_get_int(conf, CONF_height);
rlogin->firstbyte = 1;
rlogin->cansize = 0;
rlogin->prompt = NULL;
rlogin->conf = conf_copy(conf);
*backend_handle = &rlogin->backend;
addressfamily = conf_get_int(conf, CONF_addressfamily);
/*
* Try to find host.
*/
addr = name_lookup(host, port, realhost, conf, addressfamily,
rlogin->logctx, "rlogin connection");
if ((err = sk_addr_error(addr)) != NULL) {
sk_addr_free(addr);
return err;
}
if (port < 0)
port = 513; /* default rlogin port */
/*
* Open socket.
*/
rlogin->s = new_connection(addr, *realhost, port, 1, 0,
nodelay, keepalive, &rlogin->plug, conf);
if ((err = sk_socket_error(rlogin->s)) != NULL)
return err;
loghost = conf_get_str(conf, CONF_loghost);
if (*loghost) {
char *colon;
sfree(*realhost);
*realhost = dupstr(loghost);
colon = host_strrchr(*realhost, ':');
if (colon)
*colon++ = '\0';
}
/*
* Send local username, remote username, terminal type and
* terminal speed - unless we don't have the remote username yet,
* in which case we prompt for it and may end up deferring doing
* anything else until the local prompt mechanism returns.
*/
if ((ruser = get_remote_username(conf)) != NULL) {
rlogin_startup(rlogin, ruser);
sfree(ruser);
} else {
int ret;
rlogin->prompt = new_prompts(rlogin->frontend);
rlogin->prompt->to_server = TRUE;
rlogin->prompt->name = dupstr("Rlogin login name");
add_prompt(rlogin->prompt, dupstr("rlogin username: "), TRUE);
ret = get_userpass_input(rlogin->prompt, NULL);
if (ret >= 0) {
rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
}
}
return NULL;
}
static void rlogin_free(Backend *be)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
if (rlogin->prompt)
free_prompts(rlogin->prompt);
if (rlogin->s)
sk_close(rlogin->s);
conf_free(rlogin->conf);
sfree(rlogin);
}
/*
* Stub routine (we don't have any need to reconfigure this backend).
*/
static void rlogin_reconfig(Backend *be, Conf *conf)
{
}
/*
* Called to send data down the rlogin connection.
*/
static int rlogin_send(Backend *be, const char *buf, int len)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
bufchain bc;
if (rlogin->s == NULL)
return 0;
bufchain_init(&bc);
bufchain_add(&bc, buf, len);
if (rlogin->prompt) {
/*
* We're still prompting for a username, and aren't talking
* directly to the network connection yet.
*/
int ret = get_userpass_input(rlogin->prompt, &bc);
if (ret >= 0) {
rlogin_startup(rlogin, rlogin->prompt->prompts[0]->result);
/* that nulls out rlogin->prompt, so then we'll start sending
* data down the wire in the obvious way */
}
}
if (!rlogin->prompt) {
while (bufchain_size(&bc) > 0) {
void *data;
int len;
bufchain_prefix(&bc, &data, &len);
rlogin->bufsize = sk_write(rlogin->s, data, len);
bufchain_consume(&bc, len);
}
}
bufchain_clear(&bc);
return rlogin->bufsize;
}
/*
* Called to query the current socket sendability status.
*/
static int rlogin_sendbuffer(Backend *be)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
return rlogin->bufsize;
}
/*
* Called to set the size of the window
*/
static void rlogin_size(Backend *be, int width, int height)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
char b[12] = { '\xFF', '\xFF', 0x73, 0x73, 0, 0, 0, 0, 0, 0, 0, 0 };
rlogin->term_width = width;
rlogin->term_height = height;
if (rlogin->s == NULL || !rlogin->cansize)
return;
b[6] = rlogin->term_width >> 8;
b[7] = rlogin->term_width & 0xFF;
b[4] = rlogin->term_height >> 8;
b[5] = rlogin->term_height & 0xFF;
rlogin->bufsize = sk_write(rlogin->s, b, 12);
return;
}
/*
* Send rlogin special codes.
*/
static void rlogin_special(Backend *be, SessionSpecialCode code, int arg)
{
/* Do nothing! */
return;
}
/*
* Return a list of the special codes that make sense in this
* protocol.
*/
static const SessionSpecial *rlogin_get_specials(Backend *be)
{
return NULL;
}
static int rlogin_connected(Backend *be)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
return rlogin->s != NULL;
}
static int rlogin_sendok(Backend *be)
{
/* Rlogin *rlogin = container_of(be, Rlogin, backend); */
return 1;
}
static void rlogin_unthrottle(Backend *be, int backlog)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
sk_set_frozen(rlogin->s, backlog > RLOGIN_MAX_BACKLOG);
}
static int rlogin_ldisc(Backend *be, int option)
{
/* Rlogin *rlogin = container_of(be, Rlogin, backend); */
return 0;
}
static void rlogin_provide_ldisc(Backend *be, Ldisc *ldisc)
{
/* This is a stub. */
}
static int rlogin_exitcode(Backend *be)
{
Rlogin *rlogin = container_of(be, Rlogin, backend);
if (rlogin->s != NULL)
return -1; /* still connected */
else if (rlogin->closed_on_socket_error)
return INT_MAX; /* a socket error counts as an unclean exit */
else
/* If we ever implement RSH, we'll probably need to do this properly */
return 0;
}
/*
* cfg_info for rlogin does nothing at all.
*/
static int rlogin_cfg_info(Backend *be)
{
return 0;
}
const struct BackendVtable rlogin_backend = {
rlogin_init,
rlogin_free,
rlogin_reconfig,
rlogin_send,
rlogin_sendbuffer,
rlogin_size,
rlogin_special,
rlogin_get_specials,
rlogin_connected,
rlogin_exitcode,
rlogin_sendok,
rlogin_ldisc,
rlogin_provide_ldisc,
rlogin_unthrottle,
rlogin_cfg_info,
NULL /* test_for_upstream */,
"rlogin",
PROT_RLOGIN,
513
};