/* * linux/drivers/char/tty_ioctl.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines * which can be dynamically activated and de-activated by the line * discipline handling modules (like SLIP). */ #include <linux/types.h> #include <linux/termios.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/tty.h> #include <linux/fcntl.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/bitops.h> #include <linux/mutex.h> #include <asm/io.h> #include <asm/uaccess.h> #include <asm/system.h> #undef TTY_DEBUG_WAIT_UNTIL_SENT #undef DEBUG /* * Internal flag options for termios setting behavior */ #define TERMIOS_FLUSH 1 #define TERMIOS_WAIT 2 #define TERMIOS_TERMIO 4 #define TERMIOS_OLD 8 /** * tty_wait_until_sent - wait for I/O to finish * @tty: tty we are waiting for * @timeout: how long we will wait * * Wait for characters pending in a tty driver to hit the wire, or * for a timeout to occur (eg due to flow control) * * Locking: none */ void tty_wait_until_sent(struct tty_struct * tty, long timeout) { #ifdef TTY_DEBUG_WAIT_UNTIL_SENT char buf[64]; printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf)); #endif if (!tty->driver->chars_in_buffer) return; if (!timeout) timeout = MAX_SCHEDULE_TIMEOUT; if (wait_event_interruptible_timeout(tty->write_wait, !tty->driver->chars_in_buffer(tty), timeout)) return; if (tty->driver->wait_until_sent) tty->driver->wait_until_sent(tty, timeout); } EXPORT_SYMBOL(tty_wait_until_sent); static void unset_locked_termios(struct ktermios *termios, struct ktermios *old, struct ktermios *locked) { int i; #define NOSET_MASK(x,y,z) (x = ((x) & ~(z)) | ((y) & (z))) if (!locked) { printk(KERN_WARNING "Warning?!? termios_locked is NULL.\n"); return; } NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag); NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag); NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag); NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag); termios->c_line = locked->c_line ? old->c_line : termios->c_line; for (i=0; i < NCCS; i++) termios->c_cc[i] = locked->c_cc[i] ? old->c_cc[i] : termios->c_cc[i]; /* FIXME: What should we do for i/ospeed */ } /* * Routine which returns the baud rate of the tty * * Note that the baud_table needs to be kept in sync with the * include/asm/termbits.h file. */ static const speed_t baud_table[] = { 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, #ifdef __sparc__ 76800, 153600, 307200, 614400, 921600 #else 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000, 3000000, 3500000, 4000000 #endif }; #ifndef __sparc__ static const tcflag_t baud_bits[] = { B0, B50, B75, B110, B134, B150, B200, B300, B600, B1200, B1800, B2400, B4800, B9600, B19200, B38400, B57600, B115200, B230400, B460800, B500000, B576000, B921600, B1000000, B1152000, B1500000, B2000000, B2500000, B3000000, B3500000, B4000000 }; #else static const tcflag_t baud_bits[] = { B0, B50, B75, B110, B134, B150, B200, B300, B600, B1200, B1800, B2400, B4800, B9600, B19200, B38400, B57600, B115200, B230400, B460800, B76800, B153600, B307200, B614400, B921600 }; #endif static int n_baud_table = ARRAY_SIZE(baud_table); /** * tty_termios_baud_rate * @termios: termios structure * * Convert termios baud rate data into a speed. This should be called * with the termios lock held if this termios is a terminal termios * structure. May change the termios data. Device drivers can call this * function but should use ->c_[io]speed directly as they are updated. * * Locking: none */ speed_t tty_termios_baud_rate(struct ktermios *termios) { unsigned int cbaud; cbaud = termios->c_cflag & CBAUD; #ifdef BOTHER /* Magic token for arbitary speed via c_ispeed/c_ospeed */ if (cbaud == BOTHER) return termios->c_ospeed; #endif if (cbaud & CBAUDEX) { cbaud &= ~CBAUDEX; if (cbaud < 1 || cbaud + 15 > n_baud_table) termios->c_cflag &= ~CBAUDEX; else cbaud += 15; } return baud_table[cbaud]; } EXPORT_SYMBOL(tty_termios_baud_rate); /** * tty_termios_input_baud_rate * @termios: termios structure * * Convert termios baud rate data into a speed. This should be called * with the termios lock held if this termios is a terminal termios * structure. May change the termios data. Device drivers can call this * function but should use ->c_[io]speed directly as they are updated. * * Locking: none */ speed_t tty_termios_input_baud_rate(struct ktermios *termios) { #ifdef IBSHIFT unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD; if (cbaud == B0) return tty_termios_baud_rate(termios); /* Magic token for arbitary speed via c_ispeed*/ if (cbaud == BOTHER) return termios->c_ispeed; if (cbaud & CBAUDEX) { cbaud &= ~CBAUDEX; if (cbaud < 1 || cbaud + 15 > n_baud_table) termios->c_cflag &= ~(CBAUDEX << IBSHIFT); else cbaud += 15; } return baud_table[cbaud]; #else return tty_termios_baud_rate(termios); #endif } EXPORT_SYMBOL(tty_termios_input_baud_rate); #ifdef BOTHER /** * tty_termios_encode_baud_rate * @termios: ktermios structure holding user requested state * @ispeed: input speed * @ospeed: output speed * * Encode the speeds set into the passed termios structure. This is * used as a library helper for drivers os that they can report back * the actual speed selected when it differs from the speed requested * * For maximal back compatibility with legacy SYS5/POSIX *nix behaviour * we need to carefully set the bits when the user does not get the * desired speed. We allow small margins and preserve as much of possible * of the input intent to keep compatiblity. * * Locking: Caller should hold termios lock. This is already held * when calling this function from the driver termios handler. */ void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed_t obaud) { int i = 0; int ifound = -1, ofound = -1; int iclose = ibaud/50, oclose = obaud/50; int ibinput = 0; termios->c_ispeed = ibaud; termios->c_ospeed = obaud; /* If the user asked for a precise weird speed give a precise weird answer. If they asked for a Bfoo speed they many have problems digesting non-exact replies so fuzz a bit */ if ((termios->c_cflag & CBAUD) == BOTHER) oclose = 0; if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER) iclose = 0; if ((termios->c_cflag >> IBSHIFT) & CBAUD) ibinput = 1; /* An input speed was specified */ termios->c_cflag &= ~CBAUD; do { if (obaud - oclose >= baud_table[i] && obaud + oclose <= baud_table[i]) { termios->c_cflag |= baud_bits[i]; ofound = i; } if (ibaud - iclose >= baud_table[i] && ibaud + iclose <= baud_table[i]) { /* For the case input == output don't set IBAUD bits if the user didn't do so */ if (ofound != i || ibinput) termios->c_cflag |= (baud_bits[i] << IBSHIFT); ifound = i; } } while (++i < n_baud_table); if (ofound == -1) termios->c_cflag |= BOTHER; /* Set exact input bits only if the input and output differ or the user already did */ if (ifound == -1 && (ibaud != obaud || ibinput)) termios->c_cflag |= (BOTHER << IBSHIFT); } EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate); #endif /** * tty_get_baud_rate - get tty bit rates * @tty: tty to query * * Returns the baud rate as an integer for this terminal. The * termios lock must be held by the caller and the terminal bit * flags may be updated. * * Locking: none */ speed_t tty_get_baud_rate(struct tty_struct *tty) { speed_t baud = tty_termios_baud_rate(tty->termios); if (baud == 38400 && tty->alt_speed) { if (!tty->warned) { printk(KERN_WARNING "Use of setserial/setrocket to " "set SPD_* flags is deprecated\n"); tty->warned = 1; } baud = tty->alt_speed; } return baud; } EXPORT_SYMBOL(tty_get_baud_rate); /** * change_termios - update termios values * @tty: tty to update * @new_termios: desired new value * * Perform updates to the termios values set on this terminal. There * is a bit of layering violation here with n_tty in terms of the * internal knowledge of this function. * * Locking: termios_sem */ static void change_termios(struct tty_struct * tty, struct ktermios * new_termios) { int canon_change; struct ktermios old_termios = *tty->termios; struct tty_ldisc *ld; /* * Perform the actual termios internal changes under lock. */ /* FIXME: we need to decide on some locking/ordering semantics for the set_termios notification eventually */ mutex_lock(&tty->termios_mutex); *tty->termios = *new_termios; unset_locked_termios(tty->termios, &old_termios, tty->termios_locked); canon_change = (old_termios.c_lflag ^ tty->termios->c_lflag) & ICANON; if (canon_change) { memset(&tty->read_flags, 0, sizeof tty->read_flags); tty->canon_head = tty->read_tail; tty->canon_data = 0; tty->erasing = 0; } if (canon_change && !L_ICANON(tty) && tty->read_cnt) /* Get characters left over from canonical mode. */ wake_up_interruptible(&tty->read_wait); /* See if packet mode change of state. */ if (tty->link && tty->link->packet) { int old_flow = ((old_termios.c_iflag & IXON) && (old_termios.c_cc[VSTOP] == '\023') && (old_termios.c_cc[VSTART] == '\021')); int new_flow = (I_IXON(tty) && STOP_CHAR(tty) == '\023' && START_CHAR(tty) == '\021'); if (old_flow != new_flow) { tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); if (new_flow) tty->ctrl_status |= TIOCPKT_DOSTOP; else tty->ctrl_status |= TIOCPKT_NOSTOP; wake_up_interruptible(&tty->link->read_wait); } } if (tty->driver->set_termios) (*tty->driver->set_termios)(tty, &old_termios); ld = tty_ldisc_ref(tty); if (ld != NULL) { if (ld->set_termios) (ld->set_termios)(tty, &old_termios); tty_ldisc_deref(ld); } mutex_unlock(&tty->termios_mutex); } /** * set_termios - set termios values for a tty * @tty: terminal device * @arg: user data * @opt: option information * * Helper function to prepare termios data and run neccessary other * functions before using change_termios to do the actual changes. * * Locking: * Called functions take ldisc and termios_sem locks */ static int set_termios(struct tty_struct * tty, void __user *arg, int opt) { struct ktermios tmp_termios; struct tty_ldisc *ld; int retval = tty_check_change(tty); if (retval) return retval; memcpy(&tmp_termios, tty->termios, sizeof(struct ktermios)); if (opt & TERMIOS_TERMIO) { if (user_termio_to_kernel_termios(&tmp_termios, (struct termio __user *)arg)) return -EFAULT; #ifdef TCGETS2 } else if (opt & TERMIOS_OLD) { if (user_termios_to_kernel_termios_1(&tmp_termios, (struct termios __user *)arg)) return -EFAULT; } else { if (user_termios_to_kernel_termios(&tmp_termios, (struct termios2 __user *)arg)) return -EFAULT; } #else } else if (user_termios_to_kernel_termios(&tmp_termios, (struct termios __user *)arg)) return -EFAULT; #endif /* If old style Bfoo values are used then load c_ispeed/c_ospeed with the real speed so its unconditionally usable */ tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios); tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios); ld = tty_ldisc_ref(tty); if (ld != NULL) { if ((opt & TERMIOS_FLUSH) && ld->flush_buffer) ld->flush_buffer(tty); tty_ldisc_deref(ld); } if (opt & TERMIOS_WAIT) { tty_wait_until_sent(tty, 0); if (signal_pending(current)) return -EINTR; } change_termios(tty, &tmp_termios); return 0; } static int get_termio(struct tty_struct * tty, struct termio __user * termio) { if (kernel_termios_to_user_termio(termio, tty->termios)) return -EFAULT; return 0; } static unsigned long inq_canon(struct tty_struct * tty) { int nr, head, tail; if (!tty->canon_data || !tty->read_buf) return 0; head = tty->canon_head; tail = tty->read_tail; nr = (head - tail) & (N_TTY_BUF_SIZE-1); /* Skip EOF-chars.. */ while (head != tail) { if (test_bit(tail, tty->read_flags) && tty->read_buf[tail] == __DISABLED_CHAR) nr--; tail = (tail+1) & (N_TTY_BUF_SIZE-1); } return nr; } #ifdef TIOCGETP /* * These are deprecated, but there is limited support.. * * The "sg_flags" translation is a joke.. */ static int get_sgflags(struct tty_struct * tty) { int flags = 0; if (!(tty->termios->c_lflag & ICANON)) { if (tty->termios->c_lflag & ISIG) flags |= 0x02; /* cbreak */ else flags |= 0x20; /* raw */ } if (tty->termios->c_lflag & ECHO) flags |= 0x08; /* echo */ if (tty->termios->c_oflag & OPOST) if (tty->termios->c_oflag & ONLCR) flags |= 0x10; /* crmod */ return flags; } static int get_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb) { struct sgttyb tmp; mutex_lock(&tty->termios_mutex); tmp.sg_ispeed = tty->termios->c_ispeed; tmp.sg_ospeed = tty->termios->c_ospeed; tmp.sg_erase = tty->termios->c_cc[VERASE]; tmp.sg_kill = tty->termios->c_cc[VKILL]; tmp.sg_flags = get_sgflags(tty); mutex_unlock(&tty->termios_mutex); return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0; } static void set_sgflags(struct ktermios * termios, int flags) { termios->c_iflag = ICRNL | IXON; termios->c_oflag = 0; termios->c_lflag = ISIG | ICANON; if (flags & 0x02) { /* cbreak */ termios->c_iflag = 0; termios->c_lflag &= ~ICANON; } if (flags & 0x08) { /* echo */ termios->c_lflag |= ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN; } if (flags & 0x10) { /* crmod */ termios->c_oflag |= OPOST | ONLCR; } if (flags & 0x20) { /* raw */ termios->c_iflag = 0; termios->c_lflag &= ~(ISIG | ICANON); } if (!(termios->c_lflag & ICANON)) { termios->c_cc[VMIN] = 1; termios->c_cc[VTIME] = 0; } } /** * set_sgttyb - set legacy terminal values * @tty: tty structure * @sgttyb: pointer to old style terminal structure * * Updates a terminal from the legacy BSD style terminal information * structure. * * Locking: termios_sem */ static int set_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb) { int retval; struct sgttyb tmp; struct ktermios termios; retval = tty_check_change(tty); if (retval) return retval; if (copy_from_user(&tmp, sgttyb, sizeof(tmp))) return -EFAULT; mutex_lock(&tty->termios_mutex); termios = *tty->termios; termios.c_cc[VERASE] = tmp.sg_erase; termios.c_cc[VKILL] = tmp.sg_kill; set_sgflags(&termios, tmp.sg_flags); /* Try and encode into Bfoo format */ #ifdef BOTHER tty_termios_encode_baud_rate(&termios, termios.c_ispeed, termios.c_ospeed); #endif mutex_unlock(&tty->termios_mutex); change_termios(tty, &termios); return 0; } #endif #ifdef TIOCGETC static int get_tchars(struct tty_struct * tty, struct tchars __user * tchars) { struct tchars tmp; tmp.t_intrc = tty->termios->c_cc[VINTR]; tmp.t_quitc = tty->termios->c_cc[VQUIT]; tmp.t_startc = tty->termios->c_cc[VSTART]; tmp.t_stopc = tty->termios->c_cc[VSTOP]; tmp.t_eofc = tty->termios->c_cc[VEOF]; tmp.t_brkc = tty->termios->c_cc[VEOL2]; /* what is brkc anyway? */ return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; } static int set_tchars(struct tty_struct * tty, struct tchars __user * tchars) { struct tchars tmp; if (copy_from_user(&tmp, tchars, sizeof(tmp))) return -EFAULT; tty->termios->c_cc[VINTR] = tmp.t_intrc; tty->termios->c_cc[VQUIT] = tmp.t_quitc; tty->termios->c_cc[VSTART] = tmp.t_startc; tty->termios->c_cc[VSTOP] = tmp.t_stopc; tty->termios->c_cc[VEOF] = tmp.t_eofc; tty->termios->c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */ return 0; } #endif #ifdef TIOCGLTC static int get_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars) { struct ltchars tmp; tmp.t_suspc = tty->termios->c_cc[VSUSP]; tmp.t_dsuspc = tty->termios->c_cc[VSUSP]; /* what is dsuspc anyway? */ tmp.t_rprntc = tty->termios->c_cc[VREPRINT]; tmp.t_flushc = tty->termios->c_cc[VEOL2]; /* what is flushc anyway? */ tmp.t_werasc = tty->termios->c_cc[VWERASE]; tmp.t_lnextc = tty->termios->c_cc[VLNEXT]; return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; } static int set_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars) { struct ltchars tmp; if (copy_from_user(&tmp, ltchars, sizeof(tmp))) return -EFAULT; tty->termios->c_cc[VSUSP] = tmp.t_suspc; tty->termios->c_cc[VEOL2] = tmp.t_dsuspc; /* what is dsuspc anyway? */ tty->termios->c_cc[VREPRINT] = tmp.t_rprntc; tty->termios->c_cc[VEOL2] = tmp.t_flushc; /* what is flushc anyway? */ tty->termios->c_cc[VWERASE] = tmp.t_werasc; tty->termios->c_cc[VLNEXT] = tmp.t_lnextc; return 0; } #endif /** * send_prio_char - send priority character * * Send a high priority character to the tty even if stopped * * Locking: none for xchar method, write ordering for write method. */ static int send_prio_char(struct tty_struct *tty, char ch) { int was_stopped = tty->stopped; if (tty->driver->send_xchar) { tty->driver->send_xchar(tty, ch); return 0; } if (tty_write_lock(tty, 0) < 0) return -ERESTARTSYS; if (was_stopped) start_tty(tty); tty->driver->write(tty, &ch, 1); if (was_stopped) stop_tty(tty); tty_write_unlock(tty); return 0; } int n_tty_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg) { struct tty_struct * real_tty; void __user *p = (void __user *)arg; int retval; struct tty_ldisc *ld; if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) real_tty = tty->link; else real_tty = tty; switch (cmd) { #ifdef TIOCGETP case TIOCGETP: return get_sgttyb(real_tty, (struct sgttyb __user *) arg); case TIOCSETP: case TIOCSETN: return set_sgttyb(real_tty, (struct sgttyb __user *) arg); #endif #ifdef TIOCGETC case TIOCGETC: return get_tchars(real_tty, p); case TIOCSETC: return set_tchars(real_tty, p); #endif #ifdef TIOCGLTC case TIOCGLTC: return get_ltchars(real_tty, p); case TIOCSLTC: return set_ltchars(real_tty, p); #endif case TCSETSF: return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD); case TCSETSW: return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD); case TCSETS: return set_termios(real_tty, p, TERMIOS_OLD); #ifndef TCGETS2 case TCGETS: if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios)) return -EFAULT; return 0; #else case TCGETS: if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios)) return -EFAULT; return 0; case TCGETS2: if (kernel_termios_to_user_termios((struct termios2 __user *)arg, real_tty->termios)) return -EFAULT; return 0; case TCSETSF2: return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT); case TCSETSW2: return set_termios(real_tty, p, TERMIOS_WAIT); case TCSETS2: return set_termios(real_tty, p, 0); #endif case TCGETA: return get_termio(real_tty, p); case TCSETAF: return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO); case TCSETAW: return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO); case TCSETA: return set_termios(real_tty, p, TERMIOS_TERMIO); case TCXONC: retval = tty_check_change(tty); if (retval) return retval; switch (arg) { case TCOOFF: if (!tty->flow_stopped) { tty->flow_stopped = 1; stop_tty(tty); } break; case TCOON: if (tty->flow_stopped) { tty->flow_stopped = 0; start_tty(tty); } break; case TCIOFF: if (STOP_CHAR(tty) != __DISABLED_CHAR) return send_prio_char(tty, STOP_CHAR(tty)); break; case TCION: if (START_CHAR(tty) != __DISABLED_CHAR) return send_prio_char(tty, START_CHAR(tty)); break; default: return -EINVAL; } return 0; case TCFLSH: retval = tty_check_change(tty); if (retval) return retval; ld = tty_ldisc_ref(tty); switch (arg) { case TCIFLUSH: if (ld && ld->flush_buffer) ld->flush_buffer(tty); break; case TCIOFLUSH: if (ld && ld->flush_buffer) ld->flush_buffer(tty); /* fall through */ case TCOFLUSH: if (tty->driver->flush_buffer) tty->driver->flush_buffer(tty); break; default: tty_ldisc_deref(ld); return -EINVAL; } tty_ldisc_deref(ld); return 0; case TIOCOUTQ: return put_user(tty->driver->chars_in_buffer ? tty->driver->chars_in_buffer(tty) : 0, (int __user *) arg); case TIOCINQ: retval = tty->read_cnt; if (L_ICANON(tty)) retval = inq_canon(tty); return put_user(retval, (unsigned int __user *) arg); #ifndef TCGETS2 case TIOCGLCKTRMIOS: if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked)) return -EFAULT; return 0; case TIOCSLCKTRMIOS: if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (user_termios_to_kernel_termios(real_tty->termios_locked, (struct termios __user *) arg)) return -EFAULT; return 0; #else case TIOCGLCKTRMIOS: if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios_locked)) return -EFAULT; return 0; case TIOCSLCKTRMIOS: if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (user_termios_to_kernel_termios_1(real_tty->termios_locked, (struct termios __user *) arg)) return -EFAULT; return 0; #endif case TIOCPKT: { int pktmode; if (tty->driver->type != TTY_DRIVER_TYPE_PTY || tty->driver->subtype != PTY_TYPE_MASTER) return -ENOTTY; if (get_user(pktmode, (int __user *) arg)) return -EFAULT; if (pktmode) { if (!tty->packet) { tty->packet = 1; tty->link->ctrl_status = 0; } } else tty->packet = 0; return 0; } case TIOCGSOFTCAR: return put_user(C_CLOCAL(tty) ? 1 : 0, (int __user *)arg); case TIOCSSOFTCAR: if (get_user(arg, (unsigned int __user *) arg)) return -EFAULT; mutex_lock(&tty->termios_mutex); tty->termios->c_cflag = ((tty->termios->c_cflag & ~CLOCAL) | (arg ? CLOCAL : 0)); mutex_unlock(&tty->termios_mutex); return 0; default: return -ENOIOCTLCMD; } } EXPORT_SYMBOL(n_tty_ioctl);