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tty: warn on deprecated serial flags

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When somebody calls TIOCSSERIAL ioctl with serial flags to set one of
* ASYNC_SESSION_LOCKOUT
* ASYNC_PGRP_LOCKOUT
* ASYNC_CALLOUT_NOHUP
* ASYNC_AUTOPROBE
nothing happens. We actually ignore the flags for over a decade at
least (I checked 2.6.0).

So start yelling at users who use those flags, that they shouldn't.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2014-11-06 16:56:33 +01:00 committed by Greg Kroah-Hartman
parent d7685ca7c4
commit 8a8ae62f82
2 changed files with 23 additions and 0 deletions
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21
drivers/tty/tty_io.c
View file

@ -2760,6 +2760,24 @@ static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
return 0;
}
static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
{
static DEFINE_RATELIMIT_STATE(depr_flags,
DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
char comm[TASK_COMM_LEN];
int flags;
if (get_user(flags, &ss->flags))
return;
flags &= ASYNC_DEPRECATED;
if (flags && __ratelimit(&depr_flags))
pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
__func__, get_task_comm(comm, current), flags);
}
/*
* if pty, return the slave side (real_tty)
* otherwise, return self
@ -2903,6 +2921,9 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;
}
break;
case TIOCSSERIAL:
tty_warn_deprecated_flags(p);
break;
}
if (tty->ops->ioctl) {
retval = tty->ops->ioctl(tty, cmd, arg);

2
include/uapi/linux/tty_flags.h
View file

@ -64,6 +64,8 @@
#define ASYNC_MAGIC_MULTIPLIER (1U << ASYNCB_MAGIC_MULTIPLIER)
#define ASYNC_FLAGS ((1U << (ASYNCB_LAST_USER + 1)) - 1)
#define ASYNC_DEPRECATED (ASYNC_SESSION_LOCKOUT | ASYNC_PGRP_LOCKOUT | \
ASYNC_CALLOUT_NOHUP | ASYNC_AUTOPROBE)
#define ASYNC_USR_MASK (ASYNC_SPD_MASK|ASYNC_CALLOUT_NOHUP| \
ASYNC_LOW_LATENCY)
#define ASYNC_SPD_CUST (ASYNC_SPD_HI|ASYNC_SPD_VHI)