add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/tty/tty_ioctl.c
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@@ -21,6 +21,7 @@
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 #include <linux/bitops.h>
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 #include <linux/mutex.h>
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 #include <linux/compat.h>
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+#include "tty.h"
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 #include <asm/io.h>
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 #include <linux/uaccess.h>
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@@ -397,21 +398,42 @@
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 	tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
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 	tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
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-	ld = tty_ldisc_ref(tty);
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+	if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) {
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+retry_write_wait:
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+		retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty));
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+		if (retval < 0)
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+			return retval;
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-	if (ld != NULL) {
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-		if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
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-			ld->ops->flush_buffer(tty);
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-		tty_ldisc_deref(ld);
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+		if (tty_write_lock(tty, 0) < 0)
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+			goto retry_write_wait;
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+
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+		/* Racing writer? */
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+		if (tty_chars_in_buffer(tty)) {
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+			tty_write_unlock(tty);
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+			goto retry_write_wait;
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+		}
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+
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+		ld = tty_ldisc_ref(tty);
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+		if (ld != NULL) {
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+			if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
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+				ld->ops->flush_buffer(tty);
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+			tty_ldisc_deref(ld);
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+		}
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+
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+		if ((opt & TERMIOS_WAIT) && tty->ops->wait_until_sent) {
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+			tty->ops->wait_until_sent(tty, 0);
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+			if (signal_pending(current)) {
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+				tty_write_unlock(tty);
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+				return -ERESTARTSYS;
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+			}
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+		}
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+
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+		tty_set_termios(tty, &tmp_termios);
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+
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+		tty_write_unlock(tty);
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+	} else {
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+		tty_set_termios(tty, &tmp_termios);
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 	}
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-
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-	if (opt & TERMIOS_WAIT) {
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-		tty_wait_until_sent(tty, 0);
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-		if (signal_pending(current))
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-			return -ERESTARTSYS;
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-	}
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-
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-	tty_set_termios(tty, &tmp_termios);
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 	/* FIXME: Arguably if tmp_termios == tty->termios AND the
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 	   actual requested termios was not tmp_termios then we may
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@@ -442,51 +464,6 @@
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 		return -EFAULT;
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 	return 0;
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 }
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-
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-
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-#ifdef TCGETX
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-
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-/**
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- *	set_termiox	-	set termiox fields if possible
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- *	@tty: terminal
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- *	@arg: termiox structure from user
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- *	@opt: option flags for ioctl type
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- *
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- *	Implement the device calling points for the SYS5 termiox ioctl
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- *	interface in Linux
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- */
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-
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-static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
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-{
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-	struct termiox tnew;
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-	struct tty_ldisc *ld;
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-
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-	if (tty->termiox == NULL)
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-		return -EINVAL;
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-	if (copy_from_user(&tnew, arg, sizeof(struct termiox)))
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-		return -EFAULT;
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-
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-	ld = tty_ldisc_ref(tty);
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-	if (ld != NULL) {
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-		if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
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-			ld->ops->flush_buffer(tty);
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-		tty_ldisc_deref(ld);
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-	}
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-	if (opt & TERMIOS_WAIT) {
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-		tty_wait_until_sent(tty, 0);
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-		if (signal_pending(current))
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-			return -ERESTARTSYS;
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-	}
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-
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-	down_write(&tty->termios_rwsem);
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-	if (tty->ops->set_termiox)
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-		tty->ops->set_termiox(tty, &tnew);
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-	up_write(&tty->termios_rwsem);
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-	return 0;
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-}
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-
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-#endif
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-
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467
 
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 #ifdef TIOCGETP
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 /*
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@@ -815,24 +792,12 @@
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 		return ret;
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 #endif
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 #ifdef TCGETX
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-	case TCGETX: {
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-		struct termiox ktermx;
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-		if (real_tty->termiox == NULL)
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-			return -EINVAL;
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-		down_read(&real_tty->termios_rwsem);
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-		memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
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-		up_read(&real_tty->termios_rwsem);
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-		if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
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-			ret = -EFAULT;
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-		return ret;
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-	}
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+	case TCGETX:
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 	case TCSETX:
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-		return set_termiox(real_tty, p, 0);
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 	case TCSETXW:
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-		return set_termiox(real_tty, p, TERMIOS_WAIT);
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 	case TCSETXF:
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-		return set_termiox(real_tty, p, TERMIOS_FLUSH);
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-#endif		
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+		return -ENOTTY;
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+#endif
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 	case TIOCGSOFTCAR:
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 		copy_termios(real_tty, &kterm);
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 		ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
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@@ -866,7 +831,7 @@
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 			ld->ops->flush_buffer(tty);
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 			tty_unthrottle(tty);
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 		}
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-		/* fall through */
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+		fallthrough;
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 	case TCOFLUSH:
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 		tty_driver_flush_buffer(tty);
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 		break;
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@@ -941,19 +906,3 @@
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 	}
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 }
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 EXPORT_SYMBOL(n_tty_ioctl_helper);
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-
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-#ifdef CONFIG_COMPAT
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-long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
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-					unsigned int cmd, unsigned long arg)
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-{
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-	switch (cmd) {
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-	case TIOCGLCKTRMIOS:
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-	case TIOCSLCKTRMIOS:
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-		return tty_mode_ioctl(tty, file, cmd, (unsigned long) compat_ptr(arg));
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-	default:
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-		return -ENOIOCTLCMD;
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-	}
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-}
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-EXPORT_SYMBOL(n_tty_compat_ioctl_helper);
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-#endif
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-