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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