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/* vi: set sw=4 ts=4: */
/*
* Stripped down version of net-tools for busybox.
*
* Author: Ignacio Garcia Perez (iggarpe at gmail dot com)
*
* License: GPLv2 or later, see LICENSE file in this tarball.
*
* There are some differences from the standard net-tools slattach:
*
* - The -l option is not supported.
*
* - The -F options allows disabling of RTS/CTS flow control.
*/
#include "libbb.h"
#include "libiproute/utils.h" /* invarg() */
struct globals {
int handle;
int saved_disc;
struct termios saved_state;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define handle (G.handle )
#define saved_disc (G.saved_disc )
#define saved_state (G.saved_state )
#define INIT_G() do { } while (0)
/*
* Save tty state and line discipline
*
* It is fine here to bail out on errors, since we haven modified anything yet
*/
static void save_state(void)
{
/* Save line status */
if (tcgetattr(handle, &saved_state) < 0)
bb_perror_msg_and_die("get state");
/* Save line discipline */
xioctl(handle, TIOCGETD, &saved_disc);
}
static int set_termios_state_or_warn(struct termios *state)
{
int ret;
ret = tcsetattr(handle, TCSANOW, state);
if (ret < 0) {
bb_perror_msg("set state");
return 1; /* used as exitcode */
}
return 0;
}
/*
* Restore state and line discipline for ALL managed ttys
*
* Restoring ALL managed ttys is the only way to have a single
* hangup delay.
*
* Go on after errors: we want to restore as many controlled ttys
* as possible.
*/
static void restore_state_and_exit(int exitcode) NORETURN;
static void restore_state_and_exit(int exitcode)
{
struct termios state;
/* Restore line discipline */
if (ioctl_or_warn(handle, TIOCSETD, &saved_disc) < 0) {
exitcode = 1;
}
/* Hangup */
memcpy(&state, &saved_state, sizeof(state));
cfsetispeed(&state, B0);
cfsetospeed(&state, B0);
if (set_termios_state_or_warn(&state))
exitcode = 1;
sleep(1);
/* Restore line status */
if (set_termios_state_or_warn(&saved_state))
exit(EXIT_FAILURE);
if (ENABLE_FEATURE_CLEAN_UP)
close(handle);
exit(exitcode);
}
/*
* Set tty state, line discipline and encapsulation
*/
static void set_state(struct termios *state, int encap)
{
int disc;
/* Set line status */
if (set_termios_state_or_warn(state))
goto bad;
/* Set line discliple (N_SLIP always) */
disc = N_SLIP;
if (ioctl_or_warn(handle, TIOCSETD, &disc) < 0) {
goto bad;
}
/* Set encapsulation (SLIP, CSLIP, etc) */
if (ioctl_or_warn(handle, SIOCSIFENCAP, &encap) < 0) {
bad:
restore_state_and_exit(EXIT_FAILURE);
}
}
static void sig_handler(int signo UNUSED_PARAM)
{
restore_state_and_exit(EXIT_SUCCESS);
}
int slattach_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int slattach_main(int argc UNUSED_PARAM, char **argv)
{
/* Line discipline code table */
static const char proto_names[] ALIGN1 =
"slip\0" /* 0 */
"cslip\0" /* 1 */
"slip6\0" /* 2 */
"cslip6\0" /* 3 */
"adaptive\0" /* 8 */
;
int i, encap, opt;
struct termios state;
const char *proto = "cslip";
const char *extcmd; /* Command to execute after hangup */
const char *baud_str;
int baud_code = -1; /* Line baud rate (system code) */
enum {
OPT_p_proto = 1 << 0,
OPT_s_baud = 1 << 1,
OPT_c_extcmd = 1 << 2,
OPT_e_quit = 1 << 3,
OPT_h_watch = 1 << 4,
OPT_m_nonraw = 1 << 5,
OPT_L_local = 1 << 6,
OPT_F_noflow = 1 << 7
};
INIT_G();
/* Parse command line options */
opt = getopt32(argv, "p:s:c:ehmLF", &proto, &baud_str, &extcmd);
/*argc -= optind;*/
argv += optind;
if (!*argv)
bb_show_usage();
encap = index_in_strings(proto_names, proto);
if (encap < 0)
invarg(proto, "protocol");
if (encap > 3)
encap = 8;
/* We want to know if the baud rate is valid before we start touching the ttys */
if (opt & OPT_s_baud) {
baud_code = tty_value_to_baud(xatoi(baud_str));
if (baud_code < 0)
invarg(baud_str, "baud rate");
}
/* Trap signals in order to restore tty states upon exit */
if (!(opt & OPT_e_quit)) {
bb_signals(0
+ (1 << SIGHUP)
+ (1 << SIGINT)
+ (1 << SIGQUIT)
+ (1 << SIGTERM)
, sig_handler);
}
/* Open tty */
handle = open(*argv, O_RDWR | O_NDELAY);
if (handle < 0) {
char *buf = concat_path_file("/dev", *argv);
handle = xopen(buf, O_RDWR | O_NDELAY);
/* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
free(buf);
}
/* Save current tty state */
save_state();
/* Configure tty */
memcpy(&state, &saved_state, sizeof(state));
if (!(opt & OPT_m_nonraw)) { /* raw not suppressed */
memset(&state.c_cc, 0, sizeof(state.c_cc));
state.c_cc[VMIN] = 1;
state.c_iflag = IGNBRK | IGNPAR;
state.c_oflag = 0;
state.c_lflag = 0;
state.c_cflag = CS8 | HUPCL | CREAD
| ((opt & OPT_L_local) ? CLOCAL : 0)
| ((opt & OPT_F_noflow) ? 0 : CRTSCTS);
}
if (opt & OPT_s_baud) {
cfsetispeed(&state, baud_code);
cfsetospeed(&state, baud_code);
}
set_state(&state, encap);
/* Exit now if option -e was passed */
if (opt & OPT_e_quit)
return 0;
/* If we're not requested to watch, just keep descriptor open
* until we are killed */
if (!(opt & OPT_h_watch))
while (1)
sleep(24*60*60);
/* Watch line for hangup */
while (1) {
if (ioctl(handle, TIOCMGET, &i) < 0 || !(i & TIOCM_CAR))
goto no_carrier;
sleep(15);
}
no_carrier:
/* Execute command on hangup */
if (opt & OPT_c_extcmd)
system(extcmd);
/* Restore states and exit */
restore_state_and_exit(EXIT_SUCCESS);
}
|
