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Commit | Line | Data |
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8e367065 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
6 | #include <unistd.h> | |
7 | #include <stdlib.h> | |
8 | #include <termios.h> | |
9 | #include <pty.h> | |
10 | #include <signal.h> | |
11 | #include <errno.h> | |
12 | #include <string.h> | |
13 | #include <sched.h> | |
14 | #include <sys/socket.h> | |
15 | #include <sys/poll.h> | |
16 | #include "init.h" | |
17 | #include "user.h" | |
18 | #include "kern_util.h" | |
19 | #include "user_util.h" | |
20 | #include "sigio.h" | |
1da177e4 | 21 | #include "os.h" |
c13e5690 | 22 | #include "um_malloc.h" |
1da177e4 | 23 | |
f206aabb | 24 | /* Protected by sigio_lock(), also used by sigio_cleanup, which is an |
1da177e4 LT |
25 | * exitcall. |
26 | */ | |
27 | static int write_sigio_pid = -1; | |
28 | ||
29 | /* These arrays are initialized before the sigio thread is started, and | |
30 | * the descriptors closed after it is killed. So, it can't see them change. | |
31 | * On the UML side, they are changed under the sigio_lock. | |
32 | */ | |
5f4e8fd0 JD |
33 | #define SIGIO_FDS_INIT {-1, -1} |
34 | ||
35 | static int write_sigio_fds[2] = SIGIO_FDS_INIT; | |
36 | static int sigio_private[2] = SIGIO_FDS_INIT; | |
1da177e4 LT |
37 | |
38 | struct pollfds { | |
39 | struct pollfd *poll; | |
40 | int size; | |
41 | int used; | |
42 | }; | |
43 | ||
44 | /* Protected by sigio_lock(). Used by the sigio thread, but the UML thread | |
45 | * synchronizes with it. | |
46 | */ | |
19bdf040 JD |
47 | static struct pollfds current_poll; |
48 | static struct pollfds next_poll; | |
49 | static struct pollfds all_sigio_fds; | |
1da177e4 LT |
50 | |
51 | static int write_sigio_thread(void *unused) | |
52 | { | |
53 | struct pollfds *fds, tmp; | |
54 | struct pollfd *p; | |
55 | int i, n, respond_fd; | |
56 | char c; | |
57 | ||
cd2ee4a3 | 58 | signal(SIGWINCH, SIG_IGN); |
1da177e4 LT |
59 | fds = ¤t_poll; |
60 | while(1){ | |
61 | n = poll(fds->poll, fds->used, -1); | |
62 | if(n < 0){ | |
63 | if(errno == EINTR) continue; | |
64 | printk("write_sigio_thread : poll returned %d, " | |
65 | "errno = %d\n", n, errno); | |
66 | } | |
67 | for(i = 0; i < fds->used; i++){ | |
68 | p = &fds->poll[i]; | |
69 | if(p->revents == 0) continue; | |
70 | if(p->fd == sigio_private[1]){ | |
71 | n = os_read_file(sigio_private[1], &c, sizeof(c)); | |
72 | if(n != sizeof(c)) | |
73 | printk("write_sigio_thread : " | |
19bdf040 JD |
74 | "read on socket failed, " |
75 | "err = %d\n", -n); | |
1da177e4 LT |
76 | tmp = current_poll; |
77 | current_poll = next_poll; | |
78 | next_poll = tmp; | |
79 | respond_fd = sigio_private[1]; | |
80 | } | |
81 | else { | |
82 | respond_fd = write_sigio_fds[1]; | |
83 | fds->used--; | |
84 | memmove(&fds->poll[i], &fds->poll[i + 1], | |
85 | (fds->used - i) * sizeof(*fds->poll)); | |
86 | } | |
87 | ||
88 | n = os_write_file(respond_fd, &c, sizeof(c)); | |
89 | if(n != sizeof(c)) | |
19bdf040 JD |
90 | printk("write_sigio_thread : write on socket " |
91 | "failed, err = %d\n", -n); | |
1da177e4 LT |
92 | } |
93 | } | |
1b57e9c2 JD |
94 | |
95 | return 0; | |
1da177e4 LT |
96 | } |
97 | ||
19bdf040 | 98 | static int need_poll(struct pollfds *polls, int n) |
1da177e4 | 99 | { |
19bdf040 JD |
100 | if(n <= polls->size){ |
101 | polls->used = n; | |
102 | return 0; | |
1da177e4 | 103 | } |
19bdf040 JD |
104 | kfree(polls->poll); |
105 | polls->poll = um_kmalloc_atomic(n * sizeof(struct pollfd)); | |
106 | if(polls->poll == NULL){ | |
1da177e4 | 107 | printk("need_poll : failed to allocate new pollfds\n"); |
19bdf040 JD |
108 | polls->size = 0; |
109 | polls->used = 0; | |
110 | return -ENOMEM; | |
1da177e4 | 111 | } |
19bdf040 JD |
112 | polls->size = n; |
113 | polls->used = n; | |
114 | return 0; | |
1da177e4 LT |
115 | } |
116 | ||
117 | /* Must be called with sigio_lock held, because it's needed by the marked | |
19bdf040 JD |
118 | * critical section. |
119 | */ | |
1da177e4 LT |
120 | static void update_thread(void) |
121 | { | |
122 | unsigned long flags; | |
123 | int n; | |
124 | char c; | |
125 | ||
126 | flags = set_signals(0); | |
127 | n = os_write_file(sigio_private[0], &c, sizeof(c)); | |
128 | if(n != sizeof(c)){ | |
129 | printk("update_thread : write failed, err = %d\n", -n); | |
130 | goto fail; | |
131 | } | |
132 | ||
133 | n = os_read_file(sigio_private[0], &c, sizeof(c)); | |
134 | if(n != sizeof(c)){ | |
135 | printk("update_thread : read failed, err = %d\n", -n); | |
136 | goto fail; | |
137 | } | |
138 | ||
139 | set_signals(flags); | |
140 | return; | |
141 | fail: | |
142 | /* Critical section start */ | |
f206aabb | 143 | if(write_sigio_pid != -1) |
1da177e4 LT |
144 | os_kill_process(write_sigio_pid, 1); |
145 | write_sigio_pid = -1; | |
8e367065 JD |
146 | close(sigio_private[0]); |
147 | close(sigio_private[1]); | |
148 | close(write_sigio_fds[0]); | |
149 | close(write_sigio_fds[1]); | |
1da177e4 LT |
150 | /* Critical section end */ |
151 | set_signals(flags); | |
152 | } | |
153 | ||
19bdf040 | 154 | int add_sigio_fd(int fd) |
1da177e4 | 155 | { |
19bdf040 JD |
156 | struct pollfd *p; |
157 | int err = 0, i, n; | |
1da177e4 LT |
158 | |
159 | sigio_lock(); | |
19bdf040 JD |
160 | for(i = 0; i < all_sigio_fds.used; i++){ |
161 | if(all_sigio_fds.poll[i].fd == fd) | |
162 | break; | |
163 | } | |
164 | if(i == all_sigio_fds.used) | |
165 | goto out; | |
166 | ||
167 | p = &all_sigio_fds.poll[i]; | |
168 | ||
1da177e4 | 169 | for(i = 0; i < current_poll.used; i++){ |
f206aabb | 170 | if(current_poll.poll[i].fd == fd) |
1da177e4 LT |
171 | goto out; |
172 | } | |
173 | ||
174 | n = current_poll.used + 1; | |
19bdf040 | 175 | err = need_poll(&next_poll, n); |
f206aabb | 176 | if(err) |
1da177e4 LT |
177 | goto out; |
178 | ||
179 | for(i = 0; i < current_poll.used; i++) | |
180 | next_poll.poll[i] = current_poll.poll[i]; | |
181 | ||
19bdf040 | 182 | next_poll.poll[n - 1] = *p; |
1da177e4 LT |
183 | update_thread(); |
184 | out: | |
185 | sigio_unlock(); | |
19bdf040 | 186 | return err; |
1da177e4 LT |
187 | } |
188 | ||
189 | int ignore_sigio_fd(int fd) | |
190 | { | |
191 | struct pollfd *p; | |
192 | int err = 0, i, n = 0; | |
193 | ||
61232f2f JD |
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. | |
197 | */ | |
198 | if(write_sigio_pid == -1) | |
199 | return -EIO; | |
200 | ||
1da177e4 LT |
201 | sigio_lock(); |
202 | for(i = 0; i < current_poll.used; i++){ | |
203 | if(current_poll.poll[i].fd == fd) break; | |
204 | } | |
205 | if(i == current_poll.used) | |
206 | goto out; | |
f206aabb | 207 | |
19bdf040 | 208 | err = need_poll(&next_poll, current_poll.used - 1); |
1da177e4 LT |
209 | if(err) |
210 | goto out; | |
211 | ||
212 | for(i = 0; i < current_poll.used; i++){ | |
213 | p = ¤t_poll.poll[i]; | |
19bdf040 JD |
214 | if(p->fd != fd) |
215 | next_poll.poll[n++] = *p; | |
1da177e4 LT |
216 | } |
217 | ||
218 | update_thread(); | |
219 | out: | |
220 | sigio_unlock(); | |
61232f2f | 221 | return err; |
1da177e4 LT |
222 | } |
223 | ||
f206aabb | 224 | static struct pollfd *setup_initial_poll(int fd) |
1da177e4 LT |
225 | { |
226 | struct pollfd *p; | |
227 | ||
b6a2b137 PBG |
228 | p = um_kmalloc(sizeof(struct pollfd)); |
229 | if (p == NULL) { | |
1da177e4 | 230 | printk("setup_initial_poll : failed to allocate poll\n"); |
b6a2b137 | 231 | return NULL; |
1da177e4 | 232 | } |
19bdf040 | 233 | *p = ((struct pollfd) { .fd = fd, |
1da177e4 LT |
234 | .events = POLLIN, |
235 | .revents = 0 }); | |
b6a2b137 | 236 | return p; |
1da177e4 LT |
237 | } |
238 | ||
8e64d96a | 239 | static void write_sigio_workaround(void) |
1da177e4 LT |
240 | { |
241 | unsigned long stack; | |
b6a2b137 | 242 | struct pollfd *p; |
1da177e4 | 243 | int err; |
b6a2b137 PBG |
244 | int l_write_sigio_fds[2]; |
245 | int l_sigio_private[2]; | |
246 | int l_write_sigio_pid; | |
1da177e4 | 247 | |
b6a2b137 | 248 | /* We call this *tons* of times - and most ones we must just fail. */ |
1da177e4 | 249 | sigio_lock(); |
b6a2b137 PBG |
250 | l_write_sigio_pid = write_sigio_pid; |
251 | sigio_unlock(); | |
1da177e4 | 252 | |
b6a2b137 PBG |
253 | if (l_write_sigio_pid != -1) |
254 | return; | |
255 | ||
256 | err = os_pipe(l_write_sigio_fds, 1, 1); | |
1da177e4 LT |
257 | if(err < 0){ |
258 | printk("write_sigio_workaround - os_pipe 1 failed, " | |
259 | "err = %d\n", -err); | |
b6a2b137 | 260 | return; |
1da177e4 | 261 | } |
b6a2b137 | 262 | err = os_pipe(l_sigio_private, 1, 1); |
1da177e4 | 263 | if(err < 0){ |
f206aabb | 264 | printk("write_sigio_workaround - os_pipe 2 failed, " |
1da177e4 LT |
265 | "err = %d\n", -err); |
266 | goto out_close1; | |
267 | } | |
b6a2b137 PBG |
268 | |
269 | p = setup_initial_poll(l_sigio_private[1]); | |
270 | if(!p) | |
1da177e4 LT |
271 | goto out_close2; |
272 | ||
b6a2b137 PBG |
273 | sigio_lock(); |
274 | ||
275 | /* Did we race? Don't try to optimize this, please, it's not so likely | |
276 | * to happen, and no more than once at the boot. */ | |
277 | if(write_sigio_pid != -1) | |
5f4e8fd0 | 278 | goto out_free; |
1da177e4 | 279 | |
5f4e8fd0 JD |
280 | current_poll = ((struct pollfds) { .poll = p, |
281 | .used = 1, | |
282 | .size = 1 }); | |
1da177e4 | 283 | |
b6a2b137 | 284 | if (write_sigio_irq(l_write_sigio_fds[0])) |
5f4e8fd0 | 285 | goto out_clear_poll; |
1da177e4 | 286 | |
b6a2b137 PBG |
287 | memcpy(write_sigio_fds, l_write_sigio_fds, sizeof(l_write_sigio_fds)); |
288 | memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private)); | |
289 | ||
5f4e8fd0 JD |
290 | write_sigio_pid = run_helper_thread(write_sigio_thread, NULL, |
291 | CLONE_FILES | CLONE_VM, &stack, 0); | |
b6a2b137 | 292 | |
5f4e8fd0 JD |
293 | if (write_sigio_pid < 0) |
294 | goto out_clear; | |
1da177e4 | 295 | |
b6a2b137 | 296 | sigio_unlock(); |
5f4e8fd0 | 297 | return; |
b6a2b137 | 298 | |
5f4e8fd0 | 299 | out_clear: |
b6a2b137 | 300 | write_sigio_pid = -1; |
5f4e8fd0 JD |
301 | write_sigio_fds[0] = -1; |
302 | write_sigio_fds[1] = -1; | |
303 | sigio_private[0] = -1; | |
304 | sigio_private[1] = -1; | |
305 | out_clear_poll: | |
306 | current_poll = ((struct pollfds) { .poll = NULL, | |
307 | .size = 0, | |
308 | .used = 0 }); | |
309 | out_free: | |
5f4e8fd0 | 310 | sigio_unlock(); |
e6fb54ab | 311 | kfree(p); |
5f4e8fd0 | 312 | out_close2: |
8e367065 JD |
313 | close(l_sigio_private[0]); |
314 | close(l_sigio_private[1]); | |
5f4e8fd0 | 315 | out_close1: |
8e367065 JD |
316 | close(l_write_sigio_fds[0]); |
317 | close(l_write_sigio_fds[1]); | |
1da177e4 LT |
318 | } |
319 | ||
8e64d96a JD |
320 | void maybe_sigio_broken(int fd, int read) |
321 | { | |
19bdf040 JD |
322 | int err; |
323 | ||
8e64d96a JD |
324 | if(!isatty(fd)) |
325 | return; | |
326 | ||
327 | if((read || pty_output_sigio) && (!read || pty_close_sigio)) | |
328 | return; | |
329 | ||
330 | write_sigio_workaround(); | |
19bdf040 JD |
331 | |
332 | sigio_lock(); | |
333 | err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1); | |
334 | if(err){ | |
335 | printk("maybe_sigio_broken - failed to add pollfd\n"); | |
336 | goto out; | |
337 | } | |
338 | all_sigio_fds.poll[all_sigio_fds.used++] = | |
339 | ((struct pollfd) { .fd = fd, | |
340 | .events = read ? POLLIN : POLLOUT, | |
341 | .revents = 0 }); | |
342 | out: | |
343 | sigio_unlock(); | |
8e64d96a JD |
344 | } |
345 | ||
29ac1c21 | 346 | static void sigio_cleanup(void) |
1da177e4 | 347 | { |
f206aabb | 348 | if(write_sigio_pid != -1){ |
1da177e4 LT |
349 | os_kill_process(write_sigio_pid, 1); |
350 | write_sigio_pid = -1; | |
351 | } | |
352 | } | |
29ac1c21 JD |
353 | |
354 | __uml_exitcall(sigio_cleanup); |