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    Subject[PATCH 05/50] tty_ioctl(): start taking TIOC[SG]SERIAL into separate methods
    Date
    From: Al Viro <viro@zeniv.linux.org.uk>

    ->set_serial() and ->get_serial() resp., both taking tty and
    a kernel pointer to serial_struct.

    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
    ---
    drivers/tty/tty_io.c | 36 ++++++++++++++++++++++++++++++------
    include/linux/tty_driver.h | 3 +++
    2 files changed, 33 insertions(+), 6 deletions(-)

    diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
    index 2b34ccf269e0..91d73732e11c 100644
    --- a/drivers/tty/tty_io.c
    +++ b/drivers/tty/tty_io.c
    @@ -97,6 +97,7 @@
    #include <linux/seq_file.h>
    #include <linux/serial.h>
    #include <linux/ratelimit.h>
    +#include <linux/compat.h>

    #include <linux/uaccess.h>

    @@ -2455,22 +2456,40 @@ 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 int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
    {
    static DEFINE_RATELIMIT_STATE(depr_flags,
    DEFAULT_RATELIMIT_INTERVAL,
    DEFAULT_RATELIMIT_BURST);
    char comm[TASK_COMM_LEN];
    + struct serial_struct v;
    int flags;

    - if (get_user(flags, &ss->flags))
    - return;
    + if (copy_from_user(&v, ss, sizeof(struct serial_struct)))
    + return -EFAULT;

    - flags &= ASYNC_DEPRECATED;
    + flags = v.flags & ASYNC_DEPRECATED;

    if (flags && __ratelimit(&depr_flags))
    pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
    __func__, get_task_comm(comm, current), flags);
    + if (!tty->ops->set_serial)
    + return -ENOIOCTLCMD;
    + return tty->ops->set_serial(tty, &v);
    +}
    +
    +static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
    +{
    + struct serial_struct v;
    + int err;
    + memset(&v, 0, sizeof(struct serial_struct));
    +
    + if (!tty->ops->set_serial)
    + return -ENOIOCTLCMD;
    + err = tty->ops->get_serial(tty, &v);
    + if (!err && copy_to_user(ss, &v, sizeof(struct serial_struct)))
    + err = -EFAULT;
    + return err;
    }

    /*
    @@ -2602,8 +2621,13 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
    }
    break;
    case TIOCSSERIAL:
    - tty_warn_deprecated_flags(p);
    - break;
    + retval = tty_tiocsserial(tty, p);
    + if (retval != -ENOIOCTLCMD)
    + return retval;
    + case TIOCGSERIAL:
    + retval = tty_tiocgserial(tty, p);
    + if (retval != -ENOIOCTLCMD)
    + return retval;
    case TIOCGPTPEER:
    /* Special because the struct file is needed */
    return ptm_open_peer(file, tty, (int)arg);
    diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
    index 71dbc891851a..358446247ccd 100644
    --- a/include/linux/tty_driver.h
    +++ b/include/linux/tty_driver.h
    @@ -249,6 +249,7 @@
    struct tty_struct;
    struct tty_driver;
    struct serial_icounter_struct;
    +struct serial_struct;

    struct tty_operations {
    struct tty_struct * (*lookup)(struct tty_driver *driver,
    @@ -287,6 +288,8 @@ struct tty_operations {
    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);
    + int (*set_serial)(struct tty_struct *tty, struct serial_struct *p);
    void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m);
    #ifdef CONFIG_CONSOLE_POLL
    int (*poll_init)(struct tty_driver *driver, int line, char *options);
    --
    2.11.0
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