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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
/*
* CTTY.C - ctty command.
*
* Comments:
*
* Current possible problems: -- 2000/01/14 ska
*
* Problem: Only the first three handles are changed to the passed device.
* -->
* As far as I know to CTTY (Change TTY) it is not sufficient just to
* change the handles 0-2 (stdin, stdout, stderr), but one must inform
* the system that another driver is the default STDIN/OUT device,
* what would include to:
* + return ienabled STDIN/STDOUT bits when the device attributes are
* retreived via IOCTL,
* + change the pointer at LoL+0C.
* My original implication that INT-29 is effected, too, is wrong in
* the Win98 DOSbox.
*
* FreeDOS kernel 2017f passes the DOS1-compatible IO functions to
* the handle based ones, so maybe most simply programs will work?!
*
* 14 Aug 1998 (John P Price)
* - Created dummy command.
*
* 2000/01/14 ska
* + Added to change the first three handles to the given device name
* + Supports only redirection of stdin and stdout, e.g.:
* C:\> CTTY COM1 >file
* -or-
* C:\> echo Hallo | CTTY COM1 | echo du
* The CTTY command effects the commands on the _next_ line.
*/
#include "../config.h"
#include <fcntl.h>
#ifdef DEBUG
#include <dos.h>
#endif
#include <io.h>
#include <stdio.h>
#include "../include/command.h"
#include "../err_fcts.h"
#include "../include/openf.h"
#include "../strings.h"
#ifdef DEBUG
static void devAttr(int fd)
{ int attr;
if((attr = fdattr(fd)) == 0)
{
dprintf(("[Failed to read attributes of fd #%d]\n", fd));
}
else {
dbg_print("[fd #%d is", fd);
if(attr & 0x80) {
if(attr & 7) {
if(attr & 1) dbg_outs(" STDIN");
if(attr & 2) dbg_outs(" STDOUT");
if(attr & 4) dbg_outs(" NUL");
} else dbg_outs(" a device");
} else dbg_outs(" a file");
dbg_outsn("]");
}
}
#endif
int cmd_ctty(char *param)
{ int f, attr, failed;
if(!param || !*param) {
displayString(TEXT_CMDHELP_CTTY);
return 1;
}
#ifdef DEBUG
devAttr(0);
devAttr(1);
devAttr(2);
#endif
if((f = devopen(param, O_RDWR)) < 0) {
error_no_rw_device(param);
return 1;
}
if(((attr = fdattr(f)) & 0x80) == 0
|| write(f, "\r\n", 2) != 2) { /* need \r as in bin mode */
close(f);
error_no_rw_device(param);
return 1;
}
/* Now inform the system that this device is the new console
now; STDIN and STDOUT flag are the most lowest two bits */
fdsetattr(f, (attr & 0xFF) | 0x03);
fflush(stdin); /* prepare asynchroneous changes of internal fd's */
fflush(stdout);
fflush(stderr);
/* Now change the file descriptors:
0 := rdonly
1,2 := wronly
if CTTY is called within a pipe or its I/O is redirected,
oldinfd or oldoutfd is not equal to -1. In such case the
old*fd is modified in order to effect the file descriptor
after the redirections are restored. Otherwise a pipe or
redirection would left CTTY in a half-made status.
*/
failed = dup2(f, 2); /* no redirection support */
if(oldinfd != -1)
close(oldinfd);
oldinfd = f;
if(oldoutfd != -1)
close(oldoutfd);
if((oldoutfd = dup(f)) == -1)
failed = 1;
if(failed)
error_ctty_dup(param);
return failed;
}
|
