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putty-source/unix/uxser.c
Simon Tatham b4e1bca2c3 Change vtable defs to use C99 designated initialisers. 
This is a sweeping change applied across the whole code base by a spot
of Emacs Lisp. Now, everywhere I declare a vtable filled with function
pointers (and the occasional const data member), all the members of
the vtable structure are initialised by name using the '.fieldname =
value' syntax introduced in C99.

We were already using this syntax for a handful of things in the new
key-generation progress report system, so it's not new to the code
base as a whole.

The advantage is that now, when a vtable only declares a subset of the
available fields, I can initialise the rest to NULL or zero just by
leaving them out. This is most dramatic in a couple of the outlying
vtables in things like psocks (which has a ConnectionLayerVtable
containing only one non-NULL method), but less dramatically, it means
that the new 'flags' field in BackendVtable can be completely left out
of every backend definition except for the SUPDUP one which defines it
to a nonzero value. Similarly, the test_for_upstream method only used
by SSH doesn't have to be mentioned in the rest of the backends;
network Plugs for listening sockets don't have to explicitly null out
'receive' and 'sent', and vice versa for 'accepting', and so on.

While I'm at it, I've normalised the declarations so they don't use
the unnecessarily verbose 'struct' keyword. Also a handful of them
weren't const; now they are.
2020-03-10 21:06:29 +00:00

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/*
* Serial back end (Unix-specific).
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include "putty.h"
#include "tree234.h"
#define SERIAL_MAX_BACKLOG 4096
typedef struct Serial Serial;
struct Serial {
Seat *seat;
LogContext *logctx;
int fd;
bool finished;
size_t inbufsize;
bufchain output_data;
Backend backend;
};
/*
* We store our serial backends in a tree sorted by fd, so that
* when we get an uxsel notification we know which backend instance
* is the owner of the serial port that caused it.
*/
static int serial_compare_by_fd(void *av, void *bv)
{
Serial *a = (Serial *)av;
Serial *b = (Serial *)bv;
if (a->fd < b->fd)
return -1;
else if (a->fd > b->fd)
return +1;
return 0;
}
static int serial_find_by_fd(void *av, void *bv)
{
int a = *(int *)av;
Serial *b = (Serial *)bv;
if (a < b->fd)
return -1;
else if (a > b->fd)
return +1;
return 0;
}
static tree234 *serial_by_fd = NULL;
static void serial_select_result(int fd, int event);
static void serial_uxsel_setup(Serial *serial);
static void serial_try_write(Serial *serial);
static const char *serial_configure(Serial *serial, Conf *conf)
{
struct termios options;
int bflag, bval, speed, flow, parity;
const char *str;
if (serial->fd < 0)
return "Unable to reconfigure already-closed serial connection";
tcgetattr(serial->fd, &options);
/*
* Find the appropriate baud rate flag.
*/
speed = conf_get_int(conf, CONF_serspeed);
#define SETBAUD(x) (bflag = B ## x, bval = x)
#define CHECKBAUD(x) do { if (speed >= x) SETBAUD(x); } while (0)
SETBAUD(50);
#ifdef B75
CHECKBAUD(75);
#endif
#ifdef B110
CHECKBAUD(110);
#endif
#ifdef B134
CHECKBAUD(134);
#endif
#ifdef B150
CHECKBAUD(150);
#endif
#ifdef B200
CHECKBAUD(200);
#endif
#ifdef B300
CHECKBAUD(300);
#endif
#ifdef B600
CHECKBAUD(600);
#endif
#ifdef B1200
CHECKBAUD(1200);
#endif
#ifdef B1800
CHECKBAUD(1800);
#endif
#ifdef B2400
CHECKBAUD(2400);
#endif
#ifdef B4800
CHECKBAUD(4800);
#endif
#ifdef B9600
CHECKBAUD(9600);
#endif
#ifdef B19200
CHECKBAUD(19200);
#endif
#ifdef B38400
CHECKBAUD(38400);
#endif
#ifdef B57600
CHECKBAUD(57600);
#endif
#ifdef B76800
CHECKBAUD(76800);
#endif
#ifdef B115200
CHECKBAUD(115200);
#endif
#ifdef B153600
CHECKBAUD(153600);
#endif
#ifdef B230400
CHECKBAUD(230400);
#endif
#ifdef B307200
CHECKBAUD(307200);
#endif
#ifdef B460800
CHECKBAUD(460800);
#endif
#ifdef B500000
CHECKBAUD(500000);
#endif
#ifdef B576000
CHECKBAUD(576000);
#endif
#ifdef B921600
CHECKBAUD(921600);
#endif
#ifdef B1000000
CHECKBAUD(1000000);
#endif
#ifdef B1152000
CHECKBAUD(1152000);
#endif
#ifdef B1500000
CHECKBAUD(1500000);
#endif
#ifdef B2000000
CHECKBAUD(2000000);
#endif
#ifdef B2500000
CHECKBAUD(2500000);
#endif
#ifdef B3000000
CHECKBAUD(3000000);
#endif
#ifdef B3500000
CHECKBAUD(3500000);
#endif
#ifdef B4000000
CHECKBAUD(4000000);
#endif
#undef CHECKBAUD
#undef SETBAUD
cfsetispeed(&options, bflag);
cfsetospeed(&options, bflag);
logeventf(serial->logctx, "Configuring baud rate %d", bval);
options.c_cflag &= ~CSIZE;
switch (conf_get_int(conf, CONF_serdatabits)) {
case 5: options.c_cflag |= CS5; break;
case 6: options.c_cflag |= CS6; break;
case 7: options.c_cflag |= CS7; break;
case 8: options.c_cflag |= CS8; break;
default: return "Invalid number of data bits (need 5, 6, 7 or 8)";
}
logeventf(serial->logctx, "Configuring %d data bits",
conf_get_int(conf, CONF_serdatabits));
if (conf_get_int(conf, CONF_serstopbits) >= 4) {
options.c_cflag |= CSTOPB;
} else {
options.c_cflag &= ~CSTOPB;
}
logeventf(serial->logctx, "Configuring %s",
(options.c_cflag & CSTOPB ? "2 stop bits" : "1 stop bit"));
options.c_iflag &= ~(IXON|IXOFF);
#ifdef CRTSCTS
options.c_cflag &= ~CRTSCTS;
#endif
#ifdef CNEW_RTSCTS
options.c_cflag &= ~CNEW_RTSCTS;
#endif
flow = conf_get_int(conf, CONF_serflow);
if (flow == SER_FLOW_XONXOFF) {
options.c_iflag |= IXON | IXOFF;
str = "XON/XOFF";
} else if (flow == SER_FLOW_RTSCTS) {
#ifdef CRTSCTS
options.c_cflag |= CRTSCTS;
#endif
#ifdef CNEW_RTSCTS
options.c_cflag |= CNEW_RTSCTS;
#endif
str = "RTS/CTS";
} else
str = "no";
logeventf(serial->logctx, "Configuring %s flow control", str);
/* Parity */
parity = conf_get_int(conf, CONF_serparity);
if (parity == SER_PAR_ODD) {
options.c_cflag |= PARENB;
options.c_cflag |= PARODD;
str = "odd";
} else if (parity == SER_PAR_EVEN) {
options.c_cflag |= PARENB;
options.c_cflag &= ~PARODD;
str = "even";
} else {
options.c_cflag &= ~PARENB;
str = "no";
}
logeventf(serial->logctx, "Configuring %s parity", str);
options.c_cflag |= CLOCAL | CREAD;
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
options.c_iflag &= ~(ISTRIP | IGNCR | INLCR | ICRNL
#ifdef IUCLC
| IUCLC
#endif
);
options.c_oflag &= ~(OPOST
#ifdef ONLCR
| ONLCR
#endif
#ifdef OCRNL
| OCRNL
#endif
#ifdef ONOCR
| ONOCR
#endif
#ifdef ONLRET
| ONLRET
#endif
);
options.c_cc[VMIN] = 1;
options.c_cc[VTIME] = 0;
if (tcsetattr(serial->fd, TCSANOW, &options) < 0)
return "Unable to configure serial port";
return NULL;
}
/*
* Called to set up the serial 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 *serial_init(const BackendVtable *vt, Seat *seat,
Backend **backend_handle, LogContext *logctx,
Conf *conf, const char *host, int port,
char **realhost, bool nodelay, bool keepalive)
{
Serial *serial;
const char *err;
char *line;
/* No local authentication phase in this protocol */
seat_set_trust_status(seat, false);
serial = snew(Serial);
serial->backend.vt = vt;
*backend_handle = &serial->backend;
serial->seat = seat;
serial->logctx = logctx;
serial->finished = false;
serial->inbufsize = 0;
bufchain_init(&serial->output_data);
line = conf_get_str(conf, CONF_serline);
logeventf(serial->logctx, "Opening serial device %s", line);
serial->fd = open(line, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
if (serial->fd < 0)
return "Unable to open serial port";
cloexec(serial->fd);
err = serial_configure(serial, conf);
if (err)
return err;
*realhost = dupstr(line);
if (!serial_by_fd)
serial_by_fd = newtree234(serial_compare_by_fd);
add234(serial_by_fd, serial);
serial_uxsel_setup(serial);
/*
* Specials are always available.
*/
seat_update_specials_menu(serial->seat);
return NULL;
}
static void serial_close(Serial *serial)
{
if (serial->fd >= 0) {
close(serial->fd);
serial->fd = -1;
}
}
static void serial_free(Backend *be)
{
Serial *serial = container_of(be, Serial, backend);
serial_close(serial);
bufchain_clear(&serial->output_data);
sfree(serial);
}
static void serial_reconfig(Backend *be, Conf *conf)
{
Serial *serial = container_of(be, Serial, backend);
/*
* FIXME: what should we do if this returns an error?
*/
serial_configure(serial, conf);
}
static void serial_select_result(int fd, int event)
{
Serial *serial;
char buf[4096];
int ret;
bool finished = false;
serial = find234(serial_by_fd, &fd, serial_find_by_fd);
if (!serial)
return; /* spurious event; keep going */
if (event == 1) {
ret = read(serial->fd, buf, sizeof(buf));
if (ret == 0) {
/*
* Shouldn't happen on a real serial port, but I'm open
* to the idea that there might be two-way devices we
* can treat _like_ serial ports which can return EOF.
*/
finished = true;
} else if (ret < 0) {
#ifdef EAGAIN
if (errno == EAGAIN)
return; /* spurious */
#endif
#ifdef EWOULDBLOCK
if (errno == EWOULDBLOCK)
return; /* spurious */
#endif
perror("read serial port");
exit(1);
} else if (ret > 0) {
serial->inbufsize = seat_stdout(serial->seat, buf, ret);
serial_uxsel_setup(serial); /* might acquire backlog and freeze */
}
} else if (event == 2) {
/*
* Attempt to send data down the pty.
*/
serial_try_write(serial);
}
if (finished) {
serial_close(serial);
serial->finished = true;
seat_notify_remote_exit(serial->seat);
}
}
static void serial_uxsel_setup(Serial *serial)
{
int rwx = 0;
if (serial->inbufsize <= SERIAL_MAX_BACKLOG)
rwx |= SELECT_R;
if (bufchain_size(&serial->output_data))
rwx |= SELECT_W; /* might also want to write to it */
uxsel_set(serial->fd, rwx, serial_select_result);
}
static void serial_try_write(Serial *serial)
{
ssize_t ret;
assert(serial->fd >= 0);
while (bufchain_size(&serial->output_data) > 0) {
ptrlen data = bufchain_prefix(&serial->output_data);
ret = write(serial->fd, data.ptr, data.len);
if (ret < 0 && (errno == EWOULDBLOCK)) {
/*
* We've sent all we can for the moment.
*/
break;
}
if (ret < 0) {
perror("write serial port");
exit(1);
}
bufchain_consume(&serial->output_data, ret);
}
serial_uxsel_setup(serial);
}
/*
* Called to send data down the serial connection.
*/
static size_t serial_send(Backend *be, const char *buf, size_t len)
{
Serial *serial = container_of(be, Serial, backend);
if (serial->fd < 0)
return 0;
bufchain_add(&serial->output_data, buf, len);
serial_try_write(serial);
return bufchain_size(&serial->output_data);
}
/*
* Called to query the current sendability status.
*/
static size_t serial_sendbuffer(Backend *be)
{
Serial *serial = container_of(be, Serial, backend);
return bufchain_size(&serial->output_data);
}
/*
* Called to set the size of the window
*/
static void serial_size(Backend *be, int width, int height)
{
/* Do nothing! */
return;
}
/*
* Send serial special codes.
*/
static void serial_special(Backend *be, SessionSpecialCode code, int arg)
{
Serial *serial = container_of(be, Serial, backend);
if (serial->fd >= 0 && code == SS_BRK) {
tcsendbreak(serial->fd, 0);
logevent(serial->logctx, "Sending serial break at user request");
}
return;
}
/*
* Return a list of the special codes that make sense in this
* protocol.
*/
static const SessionSpecial *serial_get_specials(Backend *be)
{
static const struct SessionSpecial specials[] = {
{"Break", SS_BRK},
{NULL, SS_EXITMENU}
};
return specials;
}
static bool serial_connected(Backend *be)
{
return true; /* always connected */
}
static bool serial_sendok(Backend *be)
{
return true;
}
static void serial_unthrottle(Backend *be, size_t backlog)
{
Serial *serial = container_of(be, Serial, backend);
serial->inbufsize = backlog;
serial_uxsel_setup(serial);
}
static bool serial_ldisc(Backend *be, int option)
{
/*
* Local editing and local echo are off by default.
*/
return false;
}
static void serial_provide_ldisc(Backend *be, Ldisc *ldisc)
{
/* This is a stub. */
}
static int serial_exitcode(Backend *be)
{
Serial *serial = container_of(be, Serial, backend);
if (serial->fd >= 0)
return -1; /* still connected */
else
/* Exit codes are a meaningless concept with serial ports */
return INT_MAX;
}
/*
* cfg_info for Serial does nothing at all.
*/
static int serial_cfg_info(Backend *be)
{
return 0;
}
const BackendVtable serial_backend = {
.init = serial_init,
.free = serial_free,
.reconfig = serial_reconfig,
.send = serial_send,
.sendbuffer = serial_sendbuffer,
.size = serial_size,
.special = serial_special,
.get_specials = serial_get_specials,
.connected = serial_connected,
.exitcode = serial_exitcode,
.sendok = serial_sendok,
.ldisc_option_state = serial_ldisc,
.provide_ldisc = serial_provide_ldisc,
.unthrottle = serial_unthrottle,
.cfg_info = serial_cfg_info,
.id = "serial",
.displayname = "Serial",
.protocol = PROT_SERIAL,
};
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