udhcpc6: add DHCPv6 env helper
[oweals/busybox.git] / networking / slattach.c
index 14e0c1941361ef66b811913271a30d386f21c929..e0a388926bdf5c6ca6293ab4101e79ba63062494 100644 (file)
  *
  * - The -F options allows disabling of RTS/CTS flow control.
  */
+//config:config SLATTACH
+//config:      bool "slattach (6.1 kb)"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:      slattach configures serial line as SLIP network interface.
+
+//applet:IF_SLATTACH(APPLET(slattach, BB_DIR_SBIN, BB_SUID_DROP))
+/* shouldn't be NOEXEC: may sleep indefinitely */
+
+//kbuild:lib-$(CONFIG_SLATTACH) += slattach.o
 
 //usage:#define slattach_trivial_usage
-//usage:       "[-cehmLF] [-s SPEED] [-p PROTOCOL] DEVICE"
+//usage:       "[-ehmLF] [-c SCRIPT] [-s BAUD] [-p PROTOCOL] SERIAL_DEVICE"
 //usage:#define slattach_full_usage "\n\n"
-//usage:       "Attach network interface(s) to serial line(s)\n"
-//usage:     "\n       -p PROT Set protocol (slip, cslip, slip6, clisp6 or adaptive)"
-//usage:     "\n       -s SPD  Set line speed"
-//usage:     "\n       -e      Exit after initializing device"
-//usage:     "\n       -h      Exit when the carrier is lost"
-//usage:     "\n       -c PROG Run PROG when the line is hung up"
-//usage:     "\n       -m      Do NOT initialize the line in raw 8 bits mode"
+//usage:       "Configure serial line as SLIP network interface\n"
+//usage:     "\n       -p PROT Protocol: slip, cslip (default), slip6, clisp6, adaptive"
+//usage:     "\n       -s BAUD Line speed"
+//usage:     "\n       -e      Exit after initialization"
+//usage:     "\n       -h      Exit if carrier is lost (else never exits)"
+//usage:     "\n       -c PROG Run PROG on carrier loss"
+//usage:     "\n       -m      Do NOT set raw 8bit mode"
 //usage:     "\n       -L      Enable 3-wire operation"
 //usage:     "\n       -F      Disable RTS/CTS flow control"
 
 #include "libbb.h"
+#include "common_bufsiz.h"
 #include "libiproute/utils.h" /* invarg_1_to_2() */
 
 struct globals {
-       int handle;
        int saved_disc;
        struct termios saved_state;
 } FIX_ALIASING;
-#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)
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() do { setup_common_bufsiz(); } while (0)
 
+#define serial_fd 3
 
-/*
- * 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)
+static int tcsetattr_serial_or_warn(struct termios *state)
 {
        int ret;
 
-       ret = tcsetattr(handle, TCSANOW, state);
-       if (ret < 0) {
-               bb_perror_msg("set state");
+       ret = tcsetattr(serial_fd, TCSANOW, state);
+       if (ret != 0) {
+               bb_perror_msg("tcsetattr");
                return 1; /* used as exitcode */
        }
-       return 0;
+       return ret; /* 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) {
+       if (ioctl_or_warn(serial_fd, TIOCSETD, &G.saved_disc)) {
                exitcode = 1;
        }
 
        /* Hangup */
-       memcpy(&state, &saved_state, sizeof(state));
+       memcpy(&state, &G.saved_state, sizeof(state));
        cfsetispeed(&state, B0);
        cfsetospeed(&state, B0);
-       if (set_termios_state_or_warn(&state))
-               exitcode = 1;
+       exitcode |= tcsetattr_serial_or_warn(&state);
        sleep(1);
 
        /* Restore line status */
-       if (set_termios_state_or_warn(&saved_state))
+       if (tcsetattr_serial_or_warn(&G.saved_state))
                exit(EXIT_FAILURE);
+
        if (ENABLE_FEATURE_CLEAN_UP)
-               close(handle);
+               close(serial_fd);
 
        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);
@@ -143,13 +105,14 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
                "cslip6\0"      /* 3 */
                "adaptive\0"    /* 8 */
                ;
+       static const int int_N_SLIP = N_SLIP;
 
-       int i, encap, opt;
+       int encap, opt, fd;
        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) */
+       int baud_code = baud_code; /* for compiler */
 
        enum {
                OPT_p_proto  = 1 << 0,
@@ -165,15 +128,13 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
        INIT_G();
 
        /* Parse command line options */
-       opt = getopt32(argv, "p:s:c:ehmLF", &proto, &baud_str, &extcmd);
+       opt = getopt32(argv, "^" "p:s:c:ehmLF" "\0" "=1",
+                               &proto, &baud_str, &extcmd
+       );
        /*argc -= optind;*/
        argv += optind;
 
-       if (!*argv)
-               bb_show_usage();
-
        encap = index_in_strings(proto_names, proto);
-
        if (encap < 0)
                invarg_1_to_2(proto, "protocol");
        if (encap > 3)
@@ -186,6 +147,22 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
                        invarg_1_to_2(baud_str, "baud rate");
        }
 
+       /* Open tty */
+       fd = open(*argv, O_RDWR | O_NDELAY);
+       if (fd < 0) {
+               char *buf = concat_path_file("/dev", *argv);
+               fd = xopen(buf, O_RDWR | O_NDELAY);
+               /* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
+               free(buf);
+       }
+       xmove_fd(fd, serial_fd);
+
+       /* Save current tty state */
+       if (tcgetattr(serial_fd, &G.saved_state) != 0)
+               bb_perror_msg_and_die("tcgetattr");
+       /* Save line discipline */
+       xioctl(serial_fd, TIOCGETD, &G.saved_disc);
+
        /* Trap signals in order to restore tty states upon exit */
        if (!(opt & OPT_e_quit)) {
                bb_signals(0
@@ -196,43 +173,37 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
                        , 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));
+       memcpy(&state, &G.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_oflag = 0;*/
+               /*state.c_lflag = 0;*/
                state.c_cflag = CS8 | HUPCL | CREAD
                              | ((opt & OPT_L_local) ? CLOCAL : 0)
                              | ((opt & OPT_F_noflow) ? 0 : CRTSCTS);
-               cfsetispeed(&state, cfgetispeed(&saved_state));
-               cfsetospeed(&state, cfgetospeed(&saved_state));
+               cfsetispeed(&state, cfgetispeed(&G.saved_state));
+               cfsetospeed(&state, cfgetospeed(&G.saved_state));
        }
-
        if (opt & OPT_s_baud) {
                cfsetispeed(&state, baud_code);
                cfsetospeed(&state, baud_code);
        }
-
-       set_state(&state, encap);
+       /* Set line status */
+       if (tcsetattr_serial_or_warn(&state))
+               goto bad;
+       /* Set line disclipline (N_SLIP always) */
+       if (ioctl_or_warn(serial_fd, TIOCSETD, (void*)&int_N_SLIP))
+               goto bad;
+       /* Set encapsulation (SLIP, CSLIP, etc) */
+       if (ioctl_or_warn(serial_fd, SIOCSIFENCAP, &encap))
+               goto bad;
 
        /* Exit now if option -e was passed */
        if (opt & OPT_e_quit)
-               return 0;
+               return EXIT_SUCCESS;
 
        /* If we're not requested to watch, just keep descriptor open
         * until we are killed */
@@ -242,17 +213,20 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
 
        /* Watch line for hangup */
        while (1) {
-               if (ioctl(handle, TIOCMGET, &i) < 0 || !(i & TIOCM_CAR))
-                       goto no_carrier;
+               int modem_stat;
+               if (ioctl(serial_fd, TIOCMGET, &modem_stat))
+                       break;
+               if (!(modem_stat & TIOCM_CAR))
+                       break;
                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);
+ bad:
+       restore_state_and_exit(EXIT_FAILURE);
 }