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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/*
* Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <termios.h>
#include <string.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include "kern_util.h"
#include "user_util.h"
#include "chan_user.h"
#include "user.h"
#include "helper.h"
#include "os.h"
#include "choose-mode.h"
#include "mode.h"
int generic_console_write(int fd, const char *buf, int n, void *unused)
{
struct termios save, new;
int err;
if(isatty(fd)){
CATCH_EINTR(err = tcgetattr(fd, &save));
if (err)
goto error;
new = save;
/* The terminal becomes a bit less raw, to handle \n also as
* "Carriage Return", not only as "New Line". Otherwise, the new
* line won't start at the first column.*/
new.c_oflag |= OPOST;
CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
if (err)
goto error;
}
err = generic_write(fd, buf, n, NULL);
/* Restore raw mode, in any case; we *must* ignore any error apart
* EINTR, except for debug.*/
if(isatty(fd))
CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save));
return(err);
error:
return(-errno);
}
/*
* UML SIGWINCH handling
*
* The point of this is to handle SIGWINCH on consoles which have host ttys and
* relay them inside UML to whatever might be running on the console and cares
* about the window size (since SIGWINCH notifies about terminal size changes).
*
* So, we have a separate thread for each host tty attached to a UML device
* (side-issue - I'm annoyed that one thread can't have multiple controlling
* ttys for purposed of handling SIGWINCH, but I imagine there are other reasons
* that doesn't make any sense).
*
* SIGWINCH can't be received synchronously, so you have to set up to receive it
* as a signal. That being the case, if you are going to wait for it, it is
* convenient to sit in sigsuspend() and wait for the signal to bounce you out of
* it (see below for how we make sure to exit only on SIGWINCH).
*/
static void winch_handler(int sig)
{
}
struct winch_data {
int pty_fd;
int pipe_fd;
int close_me;
};
static int winch_thread(void *arg)
{
struct winch_data *data = arg;
sigset_t sigs;
int pty_fd, pipe_fd;
int count, err;
char c = 1;
os_close_file(data->close_me);
pty_fd = data->pty_fd;
pipe_fd = data->pipe_fd;
count = os_write_file(pipe_fd, &c, sizeof(c));
if(count != sizeof(c))
printk("winch_thread : failed to write synchronization "
"byte, err = %d\n", -count);
/* We are not using SIG_IGN on purpose, so don't fix it as I thought to
* do! If using SIG_IGN, the sigsuspend() call below would not stop on
* SIGWINCH. */
signal(SIGWINCH, winch_handler);
sigfillset(&sigs);
/* Block all signals possible. */
if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
printk("winch_thread : sigprocmask failed, errno = %d\n",
errno);
exit(1);
}
/* In sigsuspend(), block anything else than SIGWINCH. */
sigdelset(&sigs, SIGWINCH);
if(setsid() < 0){
printk("winch_thread : setsid failed, errno = %d\n", errno);
exit(1);
}
err = os_new_tty_pgrp(pty_fd, os_getpid());
if(err < 0){
printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err);
exit(1);
}
/* These are synchronization calls between various UML threads on the
* host - since they are not different kernel threads, we cannot use
* kernel semaphores. We don't use SysV semaphores because they are
* persistant. */
count = os_read_file(pipe_fd, &c, sizeof(c));
if(count != sizeof(c))
printk("winch_thread : failed to read synchronization byte, "
"err = %d\n", -count);
while(1){
/* This will be interrupted by SIGWINCH only, since other signals
* are blocked.*/
sigsuspend(&sigs);
count = os_write_file(pipe_fd, &c, sizeof(c));
if(count != sizeof(c))
printk("winch_thread : write failed, err = %d\n",
-count);
}
}
static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out)
{
struct winch_data data;
unsigned long stack;
int fds[2], n, err;
char c;
err = os_pipe(fds, 1, 1);
if(err < 0){
printk("winch_tramp : os_pipe failed, err = %d\n", -err);
goto out;
}
data = ((struct winch_data) { .pty_fd = fd,
.pipe_fd = fds[1],
.close_me = fds[0] } );
err = run_helper_thread(winch_thread, &data, 0, &stack, 0);
if(err < 0){
printk("fork of winch_thread failed - errno = %d\n", errno);
goto out_close;
}
os_close_file(fds[1]);
*fd_out = fds[0];
n = os_read_file(fds[0], &c, sizeof(c));
if(n != sizeof(c)){
printk("winch_tramp : failed to read synchronization byte\n");
printk("read failed, err = %d\n", -n);
printk("fd %d will not support SIGWINCH\n", fd);
err = -EINVAL;
goto out_close1;
}
return err ;
out_close:
os_close_file(fds[1]);
out_close1:
os_close_file(fds[0]);
out:
return err;
}
void register_winch(int fd, struct tty_struct *tty)
{
int pid, thread, thread_fd = -1;
int count;
char c = 1;
if(!isatty(fd))
return;
pid = tcgetpgrp(fd);
if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd,
tty) && (pid == -1)){
thread = winch_tramp(fd, tty, &thread_fd);
if(thread > 0){
register_winch_irq(thread_fd, fd, thread, tty);
count = os_write_file(thread_fd, &c, sizeof(c));
if(count != sizeof(c))
printk("register_winch : failed to write "
"synchronization byte, err = %d\n",
-count);
}
}
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
|
