LCOV - code coverage report
Current view: top level - include/linux - tty_ldisc.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 2 2 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : #ifndef _LINUX_TTY_LDISC_H
       2             : #define _LINUX_TTY_LDISC_H
       3             : 
       4             : /*
       5             :  * This structure defines the interface between the tty line discipline
       6             :  * implementation and the tty routines.  The following routines can be
       7             :  * defined; unless noted otherwise, they are optional, and can be
       8             :  * filled in with a null pointer.
       9             :  *
      10             :  * int  (*open)(struct tty_struct *);
      11             :  *
      12             :  *      This function is called when the line discipline is associated
      13             :  *      with the tty.  The line discipline can use this as an
      14             :  *      opportunity to initialize any state needed by the ldisc routines.
      15             :  * 
      16             :  * void (*close)(struct tty_struct *);
      17             :  *
      18             :  *      This function is called when the line discipline is being
      19             :  *      shutdown, either because the tty is being closed or because
      20             :  *      the tty is being changed to use a new line discipline
      21             :  * 
      22             :  * void (*flush_buffer)(struct tty_struct *tty);
      23             :  *
      24             :  *      This function instructs the line discipline to clear its
      25             :  *      buffers of any input characters it may have queued to be
      26             :  *      delivered to the user mode process.
      27             :  * 
      28             :  * ssize_t (*chars_in_buffer)(struct tty_struct *tty);
      29             :  *
      30             :  *      This function returns the number of input characters the line
      31             :  *      discipline may have queued up to be delivered to the user mode
      32             :  *      process.
      33             :  * 
      34             :  * ssize_t (*read)(struct tty_struct * tty, struct file * file,
      35             :  *                 unsigned char * buf, size_t nr);
      36             :  *
      37             :  *      This function is called when the user requests to read from
      38             :  *      the tty.  The line discipline will return whatever characters
      39             :  *      it has buffered up for the user.  If this function is not
      40             :  *      defined, the user will receive an EIO error.
      41             :  * 
      42             :  * ssize_t (*write)(struct tty_struct * tty, struct file * file,
      43             :  *                  const unsigned char * buf, size_t nr);
      44             :  *
      45             :  *      This function is called when the user requests to write to the
      46             :  *      tty.  The line discipline will deliver the characters to the
      47             :  *      low-level tty device for transmission, optionally performing
      48             :  *      some processing on the characters first.  If this function is
      49             :  *      not defined, the user will receive an EIO error.
      50             :  * 
      51             :  * int  (*ioctl)(struct tty_struct * tty, struct file * file,
      52             :  *               unsigned int cmd, unsigned long arg);
      53             :  *
      54             :  *      This function is called when the user requests an ioctl which
      55             :  *      is not handled by the tty layer or the low-level tty driver.
      56             :  *      It is intended for ioctls which affect line discpline
      57             :  *      operation.  Note that the search order for ioctls is (1) tty
      58             :  *      layer, (2) tty low-level driver, (3) line discpline.  So a
      59             :  *      low-level driver can "grab" an ioctl request before the line
      60             :  *      discpline has a chance to see it.
      61             :  * 
      62             :  * long (*compat_ioctl)(struct tty_struct * tty, struct file * file,
      63             :  *                      unsigned int cmd, unsigned long arg);
      64             :  *
      65             :  *      Process ioctl calls from 32-bit process on 64-bit system
      66             :  *
      67             :  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
      68             :  *
      69             :  *      This function notifies the line discpline that a change has
      70             :  *      been made to the termios structure.
      71             :  * 
      72             :  * int  (*poll)(struct tty_struct * tty, struct file * file,
      73             :  *                poll_table *wait);
      74             :  *
      75             :  *      This function is called when a user attempts to select/poll on a
      76             :  *      tty device.  It is solely the responsibility of the line
      77             :  *      discipline to handle poll requests.
      78             :  *
      79             :  * void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
      80             :  *                     char *fp, int count);
      81             :  *
      82             :  *      This function is called by the low-level tty driver to send
      83             :  *      characters received by the hardware to the line discpline for
      84             :  *      processing.  <cp> is a pointer to the buffer of input
      85             :  *      character received by the device.  <fp> is a pointer to a
      86             :  *      pointer of flag bytes which indicate whether a character was
      87             :  *      received with a parity error, etc.
      88             :  * 
      89             :  * void (*write_wakeup)(struct tty_struct *);
      90             :  *
      91             :  *      This function is called by the low-level tty driver to signal
      92             :  *      that line discpline should try to send more characters to the
      93             :  *      low-level driver for transmission.  If the line discpline does
      94             :  *      not have any more data to send, it can just return.
      95             :  *
      96             :  * int (*hangup)(struct tty_struct *)
      97             :  *
      98             :  *      Called on a hangup. Tells the discipline that it should
      99             :  *      cease I/O to the tty driver. Can sleep. The driver should
     100             :  *      seek to perform this action quickly but should wait until
     101             :  *      any pending driver I/O is completed.
     102             :  */
     103             : 
     104             : #include <linux/fs.h>
     105             : #include <linux/wait.h>
     106             : 
     107             : struct tty_ldisc_ops {
     108             :         int     magic;
     109             :         char    *name;
     110             :         int     num;
     111             :         int     flags;
     112             :         
     113             :         /*
     114             :          * The following routines are called from above.
     115             :          */
     116             :         int     (*open)(struct tty_struct *);
     117             :         void    (*close)(struct tty_struct *);
     118             :         void    (*flush_buffer)(struct tty_struct *tty);
     119             :         ssize_t (*chars_in_buffer)(struct tty_struct *tty);
     120             :         ssize_t (*read)(struct tty_struct * tty, struct file * file,
     121             :                         unsigned char __user * buf, size_t nr);
     122             :         ssize_t (*write)(struct tty_struct * tty, struct file * file,
     123             :                          const unsigned char * buf, size_t nr); 
     124             :         int     (*ioctl)(struct tty_struct * tty, struct file * file,
     125             :                          unsigned int cmd, unsigned long arg);
     126             :         long    (*compat_ioctl)(struct tty_struct * tty, struct file * file,
     127             :                                 unsigned int cmd, unsigned long arg);
     128             :         void    (*set_termios)(struct tty_struct *tty, struct ktermios * old);
     129             :         unsigned int (*poll)(struct tty_struct *, struct file *,
     130             :                              struct poll_table_struct *);
     131             :         int     (*hangup)(struct tty_struct *tty);
     132             :         
     133             :         /*
     134             :          * The following routines are called from below.
     135             :          */
     136             :         void    (*receive_buf)(struct tty_struct *, const unsigned char *cp,
     137             :                                char *fp, int count);
     138             :         void    (*write_wakeup)(struct tty_struct *);
     139             : 
     140             :         struct  module *owner;
     141             :         
     142             :         int refcount;
     143             : };
     144           1 : 
     145             : struct tty_ldisc {
     146             :         struct tty_ldisc_ops *ops;
     147             :         atomic_t users;
     148             : };
     149           1 : 
     150             : #define TTY_LDISC_MAGIC 0x5403
     151             : 
     152             : #define LDISC_FLAG_DEFINED      0x00000001
     153             : 
     154             : #define MODULE_ALIAS_LDISC(ldisc) \
     155             :         MODULE_ALIAS("tty-ldisc-" __stringify(ldisc))
     156             : 
     157             : #endif /* _LINUX_TTY_LDISC_H */

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