2 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
14 #include <sys/socket.h>
18 #include "kern_util.h"
19 #include "user_util.h"
23 /* Protected by sigio_lock(), also used by sigio_cleanup, which is an
26 static int write_sigio_pid
= -1;
28 /* These arrays are initialized before the sigio thread is started, and
29 * the descriptors closed after it is killed. So, it can't see them change.
30 * On the UML side, they are changed under the sigio_lock.
32 #define SIGIO_FDS_INIT {-1, -1}
34 static int write_sigio_fds
[2] = SIGIO_FDS_INIT
;
35 static int sigio_private
[2] = SIGIO_FDS_INIT
;
43 /* Protected by sigio_lock(). Used by the sigio thread, but the UML thread
44 * synchronizes with it.
46 static struct pollfds current_poll
= {
52 static struct pollfds next_poll
= {
58 static int write_sigio_thread(void *unused
)
60 struct pollfds
*fds
, tmp
;
65 signal(SIGWINCH
, SIG_IGN
);
68 n
= poll(fds
->poll
, fds
->used
, -1);
70 if(errno
== EINTR
) continue;
71 printk("write_sigio_thread : poll returned %d, "
72 "errno = %d\n", n
, errno
);
74 for(i
= 0; i
< fds
->used
; i
++){
76 if(p
->revents
== 0) continue;
77 if(p
->fd
== sigio_private
[1]){
78 n
= os_read_file(sigio_private
[1], &c
, sizeof(c
));
80 printk("write_sigio_thread : "
81 "read failed, err = %d\n", -n
);
83 current_poll
= next_poll
;
85 respond_fd
= sigio_private
[1];
88 respond_fd
= write_sigio_fds
[1];
90 memmove(&fds
->poll
[i
], &fds
->poll
[i
+ 1],
91 (fds
->used
- i
) * sizeof(*fds
->poll
));
94 n
= os_write_file(respond_fd
, &c
, sizeof(c
));
96 printk("write_sigio_thread : write failed, "
104 static int need_poll(int n
)
106 if(n
<= next_poll
.size
){
110 kfree(next_poll
.poll
);
111 next_poll
.poll
= um_kmalloc_atomic(n
* sizeof(struct pollfd
));
112 if(next_poll
.poll
== NULL
){
113 printk("need_poll : failed to allocate new pollfds\n");
123 /* Must be called with sigio_lock held, because it's needed by the marked
124 * critical section. */
125 static void update_thread(void)
131 flags
= set_signals(0);
132 n
= os_write_file(sigio_private
[0], &c
, sizeof(c
));
134 printk("update_thread : write failed, err = %d\n", -n
);
138 n
= os_read_file(sigio_private
[0], &c
, sizeof(c
));
140 printk("update_thread : read failed, err = %d\n", -n
);
147 /* Critical section start */
148 if(write_sigio_pid
!= -1)
149 os_kill_process(write_sigio_pid
, 1);
150 write_sigio_pid
= -1;
151 close(sigio_private
[0]);
152 close(sigio_private
[1]);
153 close(write_sigio_fds
[0]);
154 close(write_sigio_fds
[1]);
155 /* Critical section end */
159 static int add_sigio_fd(int fd
, int read
)
161 int err
= 0, i
, n
, events
;
164 for(i
= 0; i
< current_poll
.used
; i
++){
165 if(current_poll
.poll
[i
].fd
== fd
)
169 n
= current_poll
.used
+ 1;
174 for(i
= 0; i
< current_poll
.used
; i
++)
175 next_poll
.poll
[i
] = current_poll
.poll
[i
];
177 if(read
) events
= POLLIN
;
178 else events
= POLLOUT
;
180 next_poll
.poll
[n
- 1] = ((struct pollfd
) { .fd
= fd
,
189 int ignore_sigio_fd(int fd
)
192 int err
= 0, i
, n
= 0;
194 /* This is called from exitcalls elsewhere in UML - if
195 * sigio_cleanup has already run, then update_thread will hang
196 * or fail because the thread is no longer running.
198 if(write_sigio_pid
== -1)
202 for(i
= 0; i
< current_poll
.used
; i
++){
203 if(current_poll
.poll
[i
].fd
== fd
) break;
205 if(i
== current_poll
.used
)
208 err
= need_poll(current_poll
.used
- 1);
212 for(i
= 0; i
< current_poll
.used
; i
++){
213 p
= ¤t_poll
.poll
[i
];
214 if(p
->fd
!= fd
) next_poll
.poll
[n
++] = current_poll
.poll
[i
];
217 printk("ignore_sigio_fd : fd %d not found\n", fd
);
228 static struct pollfd
*setup_initial_poll(int fd
)
232 p
= um_kmalloc(sizeof(struct pollfd
));
234 printk("setup_initial_poll : failed to allocate poll\n");
237 *p
= ((struct pollfd
) { .fd
= fd
,
243 static void write_sigio_workaround(void)
248 int l_write_sigio_fds
[2];
249 int l_sigio_private
[2];
250 int l_write_sigio_pid
;
252 /* We call this *tons* of times - and most ones we must just fail. */
254 l_write_sigio_pid
= write_sigio_pid
;
257 if (l_write_sigio_pid
!= -1)
260 err
= os_pipe(l_write_sigio_fds
, 1, 1);
262 printk("write_sigio_workaround - os_pipe 1 failed, "
266 err
= os_pipe(l_sigio_private
, 1, 1);
268 printk("write_sigio_workaround - os_pipe 2 failed, "
273 p
= setup_initial_poll(l_sigio_private
[1]);
279 /* Did we race? Don't try to optimize this, please, it's not so likely
280 * to happen, and no more than once at the boot. */
281 if(write_sigio_pid
!= -1)
284 current_poll
= ((struct pollfds
) { .poll
= p
,
288 if (write_sigio_irq(l_write_sigio_fds
[0]))
291 memcpy(write_sigio_fds
, l_write_sigio_fds
, sizeof(l_write_sigio_fds
));
292 memcpy(sigio_private
, l_sigio_private
, sizeof(l_sigio_private
));
294 write_sigio_pid
= run_helper_thread(write_sigio_thread
, NULL
,
295 CLONE_FILES
| CLONE_VM
, &stack
, 0);
297 if (write_sigio_pid
< 0)
304 write_sigio_pid
= -1;
305 write_sigio_fds
[0] = -1;
306 write_sigio_fds
[1] = -1;
307 sigio_private
[0] = -1;
308 sigio_private
[1] = -1;
310 current_poll
= ((struct pollfds
) { .poll
= NULL
,
317 close(l_sigio_private
[0]);
318 close(l_sigio_private
[1]);
320 close(l_write_sigio_fds
[0]);
321 close(l_write_sigio_fds
[1]);
324 void maybe_sigio_broken(int fd
, int read
)
329 if((read
|| pty_output_sigio
) && (!read
|| pty_close_sigio
))
332 write_sigio_workaround();
333 add_sigio_fd(fd
, read
);
336 static void sigio_cleanup(void)
338 if(write_sigio_pid
!= -1){
339 os_kill_process(write_sigio_pid
, 1);
340 write_sigio_pid
= -1;
344 __uml_exitcall(sigio_cleanup
);