1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#include <syscall.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <stdio.h>
static int (*u_fcn)(); /* user functions to process read */
static int u_fd; /* fd to be monitored */
/* NOTIFY_READ -- This is a customized version of the SunView 3.2 notify_read
* primitive, the notifier's version of the UNIX read() system call (when
* the notifier is used, read() is a high level function, not a system call).
* The function of this special version of notify_read is to intercept kernel
* read calls made by the notifier for the purposes of monitoring, and
* possibly filtering, low level input from a file descriptor.
*/
notify_read (fd, buf, maxch)
int fd;
char *buf;
int maxch;
{
register int n;
/* This is a bit of a kludge, but lacking the shelltool source it
* was difficult to do better. The 18 is the size of the tty packet
* echoed by the driver when a character is typed; this is not part
* of the normal output stream so we exclude these events. The buf+1
* business is to hide the packet mode nature of the stream from the
* gtermio code; the first byte of each packet indicates the packet
* type. These details could change in a future Sun release in which
* case this code would have to be modified.
*/
if (u_fcn && fd == u_fd && maxch != 18) {
n = syscall (SYS_read, fd, buf, maxch);
if (n > 0 && *buf == TIOCPKT_DATA)
return ((*u_fcn)(buf+1, n-1, maxch-1) + 1);
else
return (n);
} else
return (syscall (SYS_read, fd, buf, maxch));
}
/* READV -- This is a customized version of the readv system call, used in
* the Release 3.4 version of ttysw to read from the pty. Usage is (appears
* to be) identical to the old notify_read, except that the TIOCPKT byte is
* returned separately from the data.
*/
readv (fd, iov, iovcnt)
register int fd;
register struct iovec *iov;
int iovcnt;
{
register int n;
if (u_fcn && fd == u_fd && iovcnt == 2 && iov[0].iov_len == 1) {
n = syscall (SYS_readv, fd, iov, iovcnt);
if (n > 0 && *(iov[0].iov_base) == TIOCPKT_DATA)
return ((*u_fcn)(iov[1].iov_base, n-1, iov[1].iov_len) + 1);
else
return (n);
} else
return (syscall (SYS_readv, fd, iov, iovcnt));
}
/* NOTIFY_READ_POST_MONITOR_FCN -- Post a user data monitor/filter function
* to process the input on the specified file descriptor. Only one file
* descriptor can be monitored at present.
*/
notify_read_post_monitor_fcn (fd, fcn)
int fd;
int (*fcn)();
{
if (u_fcn && !fcn)
return (-1);
else {
u_fcn = fcn;
u_fd = fd;
return (0);
}
}
|
