From eef2158b0c44baa8cd9855091b1d99a35e16afdb Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Thu, 3 Dec 2020 03:03:31 +0100 Subject: [PATCH] tty: Remove dead termiox code [ Upstream commit e0efb3168d34dc8c8c72718672b8902e40efff8f ] set_termiox() and the TCGETX handler bail out with -EINVAL immediately if ->termiox is NULL, but there are no code paths that can set ->termiox to a non-NULL pointer; and no such code paths seem to have existed since the termiox mechanism was introduced back in commit 1d65b4a088de ("tty: Add termiox") in v2.6.28. Similarly, no driver actually implements .set_termiox; and it looks like no driver ever has. Delete this dead code; but leave the definition of struct termiox in the UAPI headers intact. Signed-off-by: Jann Horn Link: https://lore.kernel.org/r/20201203020331.2394754-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/tty_ioctl.c | 61 ++------------------------------------ include/linux/tty.h | 1 - include/linux/tty_driver.h | 9 ------ 3 files changed, 2 insertions(+), 69 deletions(-) diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c index e18f318586ab..4de1c6ddb8ff 100644 --- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -443,51 +443,6 @@ static int get_termio(struct tty_struct *tty, struct termio __user *termio) return 0; } - -#ifdef TCGETX - -/** - * set_termiox - set termiox fields if possible - * @tty: terminal - * @arg: termiox structure from user - * @opt: option flags for ioctl type - * - * Implement the device calling points for the SYS5 termiox ioctl - * interface in Linux - */ - -static int set_termiox(struct tty_struct *tty, void __user *arg, int opt) -{ - struct termiox tnew; - struct tty_ldisc *ld; - - if (tty->termiox == NULL) - return -EINVAL; - if (copy_from_user(&tnew, arg, sizeof(struct termiox))) - return -EFAULT; - - ld = tty_ldisc_ref(tty); - if (ld != NULL) { - if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer) - ld->ops->flush_buffer(tty); - tty_ldisc_deref(ld); - } - if (opt & TERMIOS_WAIT) { - tty_wait_until_sent(tty, 0); - if (signal_pending(current)) - return -ERESTARTSYS; - } - - down_write(&tty->termios_rwsem); - if (tty->ops->set_termiox) - tty->ops->set_termiox(tty, &tnew); - up_write(&tty->termios_rwsem); - return 0; -} - -#endif - - #ifdef TIOCGETP /* * These are deprecated, but there is limited support.. @@ -815,23 +770,11 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file, return ret; #endif #ifdef TCGETX - case TCGETX: { - struct termiox ktermx; - if (real_tty->termiox == NULL) - return -EINVAL; - down_read(&real_tty->termios_rwsem); - memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox)); - up_read(&real_tty->termios_rwsem); - if (copy_to_user(p, &ktermx, sizeof(struct termiox))) - ret = -EFAULT; - return ret; - } + case TCGETX: case TCSETX: - return set_termiox(real_tty, p, 0); case TCSETXW: - return set_termiox(real_tty, p, TERMIOS_WAIT); case TCSETXF: - return set_termiox(real_tty, p, TERMIOS_FLUSH); + return -EINVAL; #endif case TIOCGSOFTCAR: copy_termios(real_tty, &kterm); diff --git a/include/linux/tty.h b/include/linux/tty.h index bc8caac390fc..5972f43b9d5a 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -303,7 +303,6 @@ struct tty_struct { spinlock_t flow_lock; /* Termios values are protected by the termios rwsem */ struct ktermios termios, termios_locked; - struct termiox *termiox; /* May be NULL for unsupported */ char name[64]; struct pid *pgrp; /* Protected by ctrl lock */ /* diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 7186d77f431e..2f719b471d52 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -224,14 +224,6 @@ * line). See tty_do_resize() if you need to wrap the standard method * in your own logic - the usual case. * - * void (*set_termiox)(struct tty_struct *tty, struct termiox *new); - * - * Called when the device receives a termiox based ioctl. Passes down - * the requested data from user space. This method will not be invoked - * unless the tty also has a valid tty->termiox pointer. - * - * Optional: Called under the termios lock - * * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount); * * Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel @@ -285,7 +277,6 @@ struct tty_operations { int (*tiocmset)(struct tty_struct *tty, unsigned int set, unsigned int clear); int (*resize)(struct tty_struct *tty, struct winsize *ws); - int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew); int (*get_icount)(struct tty_struct *tty, struct serial_icounter_struct *icount); int (*get_serial)(struct tty_struct *tty, struct serial_struct *p);