--- /dev/null
+/*
+ * 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"
+
+/* Line discipline code table */
+static const char *const proto_names[] = {
+ "slip", /* 0 */
+ "cslip", /* 1 */
+ "slip6", /* 2 */
+ "cslip6", /* 3 */
+ "adaptive", /* 8 */
+ NULL
+};
+
+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 */
+ if (ioctl(handle, TIOCGETD, &saved_disc) < 0)
+ bb_perror_msg_and_die("get discipline");
+}
+
+/*
+ * 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) ATTRIBUTE_NORETURN;
+static void restore_state_and_exit(int exitcode)
+{
+ struct termios state;
+
+ /* Restore line discipline */
+ if (ioctl(handle, TIOCSETD, &saved_disc) < 0) {
+ bb_perror_msg("set discipline");
+ exitcode = 1;
+ }
+
+ /* Hangup */
+ memcpy(&state, &saved_state, sizeof(state));
+ cfsetispeed(&state, B0);
+ cfsetospeed(&state, B0);
+ if (tcsetattr(handle, TCSANOW, &state) < 0) {
+ bb_perror_msg("set state");
+ exitcode = 1;
+ }
+
+ sleep(1);
+
+ /* Restore line status */
+ if (tcsetattr(handle, TCSANOW, &saved_state) < 0) {
+ bb_perror_msg_and_die("set state");
+ }
+
+ 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 (tcsetattr(handle, TCSANOW, state) < 0) {
+ bb_perror_msg("set state");
+ goto bad;
+ }
+
+ /* Set line discliple (N_SLIP always) */
+ disc = N_SLIP;
+ if (ioctl(handle, TIOCSETD, &disc) < 0) {
+ bb_perror_msg("set discipline");
+ goto bad;
+ }
+
+ /* Set encapsulation (SLIP, CSLIP, etc) */
+ if (ioctl(handle, SIOCSIFENCAP, &encap) < 0) {
+ bb_perror_msg("set encapsulation");
+ bad:
+ restore_state_and_exit(1);
+ }
+}
+
+static void sig_handler(int signo)
+{
+ restore_state_and_exit(0);
+}
+
+int slattach_main(int argc, char **argv);
+int slattach_main(int argc, char **argv)
+{
+ 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(argc, argv, "p:s:c:ehmLF", &proto, &baud_str, &extcmd);
+ /*argc -= optind;*/
+ argv += optind;
+
+ if (!*argv)
+ bb_show_usage();
+
+ encap = index_in_str_array(proto_names, proto);
+
+ if (encap < 0)
+ bb_error_msg_and_die("invalid protocol %s", proto);
+ 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)
+ bb_error_msg_and_die("invalid baud rate");
+ }
+
+ /* Trap signals in order to restore tty states upon exit */
+ if (!(opt & OPT_e_quit)) {
+ signal(SIGHUP, sig_handler);
+ signal(SIGINT, sig_handler);
+ signal(SIGQUIT, sig_handler);
+ signal(SIGTERM, sig_handler);
+ }
+
+ /* Open tty */
+ handle = open(*argv, O_RDWR | O_NDELAY);
+ if (handle < 0) {
+ char *buf = xasprintf("/dev/%s", *argv);
+ handle = xopen(buf, O_RDWR | O_NDELAY);
+ /* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
+ free(buf);
+ }
+
+ /* Save current tty state */
+ save_state();
+
+ /* Confgure 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
+ * till 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(0);
+}
projects / oweals / busybox.git / commitdiff