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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/minmax.h>
7#include <unistd.h>
8#include <errno.h>
9#include <fcntl.h>
10#include <poll.h>
11#include <pty.h>
12#include <sched.h>
13#include <signal.h>
14#include <string.h>
15#include <kern_util.h>
16#include <init.h>
17#include <os.h>
18#include <sigio.h>
19#include <um_malloc.h>
20
21/*
22 * Protected by sigio_lock(), also used by sigio_cleanup, which is an
23 * exitcall.
24 */
25static int write_sigio_pid = -1;
26static unsigned long write_sigio_stack;
27
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 */
33#define SIGIO_FDS_INIT {-1, -1}
34
35static int write_sigio_fds[2] = SIGIO_FDS_INIT;
36static int sigio_private[2] = SIGIO_FDS_INIT;
37
38struct pollfds {
39 struct pollfd *poll;
40 int size;
41 int used;
42};
43
44/*
45 * Protected by sigio_lock(). Used by the sigio thread, but the UML thread
46 * synchronizes with it.
47 */
48static struct pollfds current_poll;
49static struct pollfds next_poll;
50static struct pollfds all_sigio_fds;
51
52static int write_sigio_thread(void *unused)
53{
54 struct pollfds *fds;
55 struct pollfd *p;
56 int i, n, respond_fd;
57 char c;
58
59 os_fix_helper_signals();
60 fds = ¤t_poll;
61 while (1) {
62 n = poll(fds->poll, fds->used, -1);
63 if (n < 0) {
64 if (errno == EINTR)
65 continue;
66 printk(UM_KERN_ERR "write_sigio_thread : poll returned "
67 "%d, errno = %d\n", n, errno);
68 }
69 for (i = 0; i < fds->used; i++) {
70 p = &fds->poll[i];
71 if (p->revents == 0)
72 continue;
73 if (p->fd == sigio_private[1]) {
74 CATCH_EINTR(n = read(sigio_private[1], &c,
75 sizeof(c)));
76 if (n != sizeof(c))
77 printk(UM_KERN_ERR
78 "write_sigio_thread : "
79 "read on socket failed, "
80 "err = %d\n", errno);
81 swap(current_poll, next_poll);
82 respond_fd = sigio_private[1];
83 }
84 else {
85 respond_fd = write_sigio_fds[1];
86 fds->used--;
87 memmove(&fds->poll[i], &fds->poll[i + 1],
88 (fds->used - i) * sizeof(*fds->poll));
89 }
90
91 CATCH_EINTR(n = write(respond_fd, &c, sizeof(c)));
92 if (n != sizeof(c))
93 printk(UM_KERN_ERR "write_sigio_thread : "
94 "write on socket failed, err = %d\n",
95 errno);
96 }
97 }
98
99 return 0;
100}
101
102static int need_poll(struct pollfds *polls, int n)
103{
104 struct pollfd *new;
105
106 if (n <= polls->size)
107 return 0;
108
109 new = uml_kmalloc(n * sizeof(struct pollfd), UM_GFP_ATOMIC);
110 if (new == NULL) {
111 printk(UM_KERN_ERR "need_poll : failed to allocate new "
112 "pollfds\n");
113 return -ENOMEM;
114 }
115
116 memcpy(new, polls->poll, polls->used * sizeof(struct pollfd));
117 kfree(polls->poll);
118
119 polls->poll = new;
120 polls->size = n;
121 return 0;
122}
123
124/*
125 * Must be called with sigio_lock held, because it's needed by the marked
126 * critical section.
127 */
128static void update_thread(void)
129{
130 unsigned long flags;
131 int n;
132 char c;
133
134 flags = um_set_signals_trace(0);
135 CATCH_EINTR(n = write(sigio_private[0], &c, sizeof(c)));
136 if (n != sizeof(c)) {
137 printk(UM_KERN_ERR "update_thread : write failed, err = %d\n",
138 errno);
139 goto fail;
140 }
141
142 CATCH_EINTR(n = read(sigio_private[0], &c, sizeof(c)));
143 if (n != sizeof(c)) {
144 printk(UM_KERN_ERR "update_thread : read failed, err = %d\n",
145 errno);
146 goto fail;
147 }
148
149 um_set_signals_trace(flags);
150 return;
151 fail:
152 /* Critical section start */
153 if (write_sigio_pid != -1) {
154 os_kill_process(write_sigio_pid, 1);
155 free_stack(write_sigio_stack, 0);
156 }
157 write_sigio_pid = -1;
158 close(sigio_private[0]);
159 close(sigio_private[1]);
160 close(write_sigio_fds[0]);
161 close(write_sigio_fds[1]);
162 /* Critical section end */
163 um_set_signals_trace(flags);
164}
165
166int __add_sigio_fd(int fd)
167{
168 struct pollfd *p;
169 int err, i, n;
170
171 for (i = 0; i < all_sigio_fds.used; i++) {
172 if (all_sigio_fds.poll[i].fd == fd)
173 break;
174 }
175 if (i == all_sigio_fds.used)
176 return -ENOSPC;
177
178 p = &all_sigio_fds.poll[i];
179
180 for (i = 0; i < current_poll.used; i++) {
181 if (current_poll.poll[i].fd == fd)
182 return 0;
183 }
184
185 n = current_poll.used;
186 err = need_poll(&next_poll, n + 1);
187 if (err)
188 return err;
189
190 memcpy(next_poll.poll, current_poll.poll,
191 current_poll.used * sizeof(struct pollfd));
192 next_poll.poll[n] = *p;
193 next_poll.used = n + 1;
194 update_thread();
195
196 return 0;
197}
198
199
200int add_sigio_fd(int fd)
201{
202 int err;
203
204 sigio_lock();
205 err = __add_sigio_fd(fd);
206 sigio_unlock();
207
208 return err;
209}
210
211int __ignore_sigio_fd(int fd)
212{
213 struct pollfd *p;
214 int err, i, n = 0;
215
216 /*
217 * This is called from exitcalls elsewhere in UML - if
218 * sigio_cleanup has already run, then update_thread will hang
219 * or fail because the thread is no longer running.
220 */
221 if (write_sigio_pid == -1)
222 return -EIO;
223
224 for (i = 0; i < current_poll.used; i++) {
225 if (current_poll.poll[i].fd == fd)
226 break;
227 }
228 if (i == current_poll.used)
229 return -ENOENT;
230
231 err = need_poll(&next_poll, current_poll.used - 1);
232 if (err)
233 return err;
234
235 for (i = 0; i < current_poll.used; i++) {
236 p = ¤t_poll.poll[i];
237 if (p->fd != fd)
238 next_poll.poll[n++] = *p;
239 }
240 next_poll.used = current_poll.used - 1;
241
242 update_thread();
243
244 return 0;
245}
246
247int ignore_sigio_fd(int fd)
248{
249 int err;
250
251 sigio_lock();
252 err = __ignore_sigio_fd(fd);
253 sigio_unlock();
254
255 return err;
256}
257
258static struct pollfd *setup_initial_poll(int fd)
259{
260 struct pollfd *p;
261
262 p = uml_kmalloc(sizeof(struct pollfd), UM_GFP_KERNEL);
263 if (p == NULL) {
264 printk(UM_KERN_ERR "setup_initial_poll : failed to allocate "
265 "poll\n");
266 return NULL;
267 }
268 *p = ((struct pollfd) { .fd = fd,
269 .events = POLLIN,
270 .revents = 0 });
271 return p;
272}
273
274static void write_sigio_workaround(void)
275{
276 struct pollfd *p;
277 int err;
278 int l_write_sigio_fds[2];
279 int l_sigio_private[2];
280 int l_write_sigio_pid;
281
282 /* We call this *tons* of times - and most ones we must just fail. */
283 sigio_lock();
284 l_write_sigio_pid = write_sigio_pid;
285 sigio_unlock();
286
287 if (l_write_sigio_pid != -1)
288 return;
289
290 err = os_pipe(l_write_sigio_fds, 1, 1);
291 if (err < 0) {
292 printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 1 failed, "
293 "err = %d\n", -err);
294 return;
295 }
296 err = os_pipe(l_sigio_private, 1, 1);
297 if (err < 0) {
298 printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 2 failed, "
299 "err = %d\n", -err);
300 goto out_close1;
301 }
302
303 p = setup_initial_poll(l_sigio_private[1]);
304 if (!p)
305 goto out_close2;
306
307 sigio_lock();
308
309 /*
310 * Did we race? Don't try to optimize this, please, it's not so likely
311 * to happen, and no more than once at the boot.
312 */
313 if (write_sigio_pid != -1)
314 goto out_free;
315
316 current_poll = ((struct pollfds) { .poll = p,
317 .used = 1,
318 .size = 1 });
319
320 if (write_sigio_irq(l_write_sigio_fds[0]))
321 goto out_clear_poll;
322
323 memcpy(write_sigio_fds, l_write_sigio_fds, sizeof(l_write_sigio_fds));
324 memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private));
325
326 write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
327 CLONE_FILES | CLONE_VM,
328 &write_sigio_stack);
329
330 if (write_sigio_pid < 0)
331 goto out_clear;
332
333 sigio_unlock();
334 return;
335
336out_clear:
337 write_sigio_pid = -1;
338 write_sigio_fds[0] = -1;
339 write_sigio_fds[1] = -1;
340 sigio_private[0] = -1;
341 sigio_private[1] = -1;
342out_clear_poll:
343 current_poll = ((struct pollfds) { .poll = NULL,
344 .size = 0,
345 .used = 0 });
346out_free:
347 sigio_unlock();
348 kfree(p);
349out_close2:
350 close(l_sigio_private[0]);
351 close(l_sigio_private[1]);
352out_close1:
353 close(l_write_sigio_fds[0]);
354 close(l_write_sigio_fds[1]);
355}
356
357void sigio_broken(int fd)
358{
359 int err;
360
361 write_sigio_workaround();
362
363 sigio_lock();
364 err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1);
365 if (err) {
366 printk(UM_KERN_ERR "maybe_sigio_broken - failed to add pollfd "
367 "for descriptor %d\n", fd);
368 goto out;
369 }
370
371 all_sigio_fds.poll[all_sigio_fds.used++] =
372 ((struct pollfd) { .fd = fd,
373 .events = POLLIN,
374 .revents = 0 });
375out:
376 sigio_unlock();
377}
378
379/* Changed during early boot */
380static int pty_output_sigio;
381
382void maybe_sigio_broken(int fd)
383{
384 if (!isatty(fd))
385 return;
386
387 if (pty_output_sigio)
388 return;
389
390 sigio_broken(fd);
391}
392
393static void sigio_cleanup(void)
394{
395 if (write_sigio_pid == -1)
396 return;
397
398 os_kill_process(write_sigio_pid, 1);
399 free_stack(write_sigio_stack, 0);
400 write_sigio_pid = -1;
401}
402
403__uml_exitcall(sigio_cleanup);
404
405/* Used as a flag during SIGIO testing early in boot */
406static int got_sigio;
407
408static void __init handler(int sig)
409{
410 got_sigio = 1;
411}
412
413struct openpty_arg {
414 int master;
415 int slave;
416 int err;
417};
418
419static void openpty_cb(void *arg)
420{
421 struct openpty_arg *info = arg;
422
423 info->err = 0;
424 if (openpty(&info->master, &info->slave, NULL, NULL, NULL))
425 info->err = -errno;
426}
427
428static int async_pty(int master, int slave)
429{
430 int flags;
431
432 flags = fcntl(master, F_GETFL);
433 if (flags < 0)
434 return -errno;
435
436 if ((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
437 (fcntl(master, F_SETOWN, os_getpid()) < 0))
438 return -errno;
439
440 if ((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
441 return -errno;
442
443 return 0;
444}
445
446static void __init check_one_sigio(void (*proc)(int, int))
447{
448 struct sigaction old, new;
449 struct openpty_arg pty = { .master = -1, .slave = -1 };
450 int master, slave, err;
451
452 initial_thread_cb(openpty_cb, &pty);
453 if (pty.err) {
454 printk(UM_KERN_ERR "check_one_sigio failed, errno = %d\n",
455 -pty.err);
456 return;
457 }
458
459 master = pty.master;
460 slave = pty.slave;
461
462 if ((master == -1) || (slave == -1)) {
463 printk(UM_KERN_ERR "check_one_sigio failed to allocate a "
464 "pty\n");
465 return;
466 }
467
468 /* Not now, but complain so we now where we failed. */
469 err = raw(master);
470 if (err < 0) {
471 printk(UM_KERN_ERR "check_one_sigio : raw failed, errno = %d\n",
472 -err);
473 return;
474 }
475
476 err = async_pty(master, slave);
477 if (err < 0) {
478 printk(UM_KERN_ERR "check_one_sigio : sigio_async failed, "
479 "err = %d\n", -err);
480 return;
481 }
482
483 if (sigaction(SIGIO, NULL, &old) < 0) {
484 printk(UM_KERN_ERR "check_one_sigio : sigaction 1 failed, "
485 "errno = %d\n", errno);
486 return;
487 }
488
489 new = old;
490 new.sa_handler = handler;
491 if (sigaction(SIGIO, &new, NULL) < 0) {
492 printk(UM_KERN_ERR "check_one_sigio : sigaction 2 failed, "
493 "errno = %d\n", errno);
494 return;
495 }
496
497 got_sigio = 0;
498 (*proc)(master, slave);
499
500 close(master);
501 close(slave);
502
503 if (sigaction(SIGIO, &old, NULL) < 0)
504 printk(UM_KERN_ERR "check_one_sigio : sigaction 3 failed, "
505 "errno = %d\n", errno);
506}
507
508static void tty_output(int master, int slave)
509{
510 int n;
511 char buf[512];
512
513 printk(UM_KERN_INFO "Checking that host ptys support output SIGIO...");
514
515 memset(buf, 0, sizeof(buf));
516
517 while (write(master, buf, sizeof(buf)) > 0) ;
518 if (errno != EAGAIN)
519 printk(UM_KERN_ERR "tty_output : write failed, errno = %d\n",
520 errno);
521 while (((n = read(slave, buf, sizeof(buf))) > 0) &&
522 !({ barrier(); got_sigio; }))
523 ;
524
525 if (got_sigio) {
526 printk(UM_KERN_CONT "Yes\n");
527 pty_output_sigio = 1;
528 } else if (n == -EAGAIN)
529 printk(UM_KERN_CONT "No, enabling workaround\n");
530 else
531 printk(UM_KERN_CONT "tty_output : read failed, err = %d\n", n);
532}
533
534static void __init check_sigio(void)
535{
536 if ((access("/dev/ptmx", R_OK) < 0) &&
537 (access("/dev/ptyp0", R_OK) < 0)) {
538 printk(UM_KERN_WARNING "No pseudo-terminals available - "
539 "skipping pty SIGIO check\n");
540 return;
541 }
542 check_one_sigio(tty_output);
543}
544
545/* Here because it only does the SIGIO testing for now */
546void __init os_check_bugs(void)
547{
548 check_sigio();
549}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <unistd.h>
7#include <errno.h>
8#include <fcntl.h>
9#include <poll.h>
10#include <pty.h>
11#include <sched.h>
12#include <signal.h>
13#include <string.h>
14#include <kern_util.h>
15#include <init.h>
16#include <os.h>
17#include <sigio.h>
18#include <um_malloc.h>
19
20/*
21 * Protected by sigio_lock(), also used by sigio_cleanup, which is an
22 * exitcall.
23 */
24static int write_sigio_pid = -1;
25static unsigned long write_sigio_stack;
26
27/*
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.
31 */
32#define SIGIO_FDS_INIT {-1, -1}
33
34static int write_sigio_fds[2] = SIGIO_FDS_INIT;
35static int sigio_private[2] = SIGIO_FDS_INIT;
36
37struct pollfds {
38 struct pollfd *poll;
39 int size;
40 int used;
41};
42
43/*
44 * Protected by sigio_lock(). Used by the sigio thread, but the UML thread
45 * synchronizes with it.
46 */
47static struct pollfds current_poll;
48static struct pollfds next_poll;
49static struct pollfds all_sigio_fds;
50
51static 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
58 os_set_pdeathsig();
59 os_fix_helper_signals();
60 fds = ¤t_poll;
61 while (1) {
62 n = poll(fds->poll, fds->used, -1);
63 if (n < 0) {
64 if (errno == EINTR)
65 continue;
66 printk(UM_KERN_ERR "write_sigio_thread : poll returned "
67 "%d, errno = %d\n", n, errno);
68 }
69 for (i = 0; i < fds->used; i++) {
70 p = &fds->poll[i];
71 if (p->revents == 0)
72 continue;
73 if (p->fd == sigio_private[1]) {
74 CATCH_EINTR(n = read(sigio_private[1], &c,
75 sizeof(c)));
76 if (n != sizeof(c))
77 printk(UM_KERN_ERR
78 "write_sigio_thread : "
79 "read on socket failed, "
80 "err = %d\n", errno);
81 tmp = current_poll;
82 current_poll = next_poll;
83 next_poll = tmp;
84 respond_fd = sigio_private[1];
85 }
86 else {
87 respond_fd = write_sigio_fds[1];
88 fds->used--;
89 memmove(&fds->poll[i], &fds->poll[i + 1],
90 (fds->used - i) * sizeof(*fds->poll));
91 }
92
93 CATCH_EINTR(n = write(respond_fd, &c, sizeof(c)));
94 if (n != sizeof(c))
95 printk(UM_KERN_ERR "write_sigio_thread : "
96 "write on socket failed, err = %d\n",
97 errno);
98 }
99 }
100
101 return 0;
102}
103
104static int need_poll(struct pollfds *polls, int n)
105{
106 struct pollfd *new;
107
108 if (n <= polls->size)
109 return 0;
110
111 new = uml_kmalloc(n * sizeof(struct pollfd), UM_GFP_ATOMIC);
112 if (new == NULL) {
113 printk(UM_KERN_ERR "need_poll : failed to allocate new "
114 "pollfds\n");
115 return -ENOMEM;
116 }
117
118 memcpy(new, polls->poll, polls->used * sizeof(struct pollfd));
119 kfree(polls->poll);
120
121 polls->poll = new;
122 polls->size = n;
123 return 0;
124}
125
126/*
127 * Must be called with sigio_lock held, because it's needed by the marked
128 * critical section.
129 */
130static void update_thread(void)
131{
132 unsigned long flags;
133 int n;
134 char c;
135
136 flags = um_set_signals_trace(0);
137 CATCH_EINTR(n = write(sigio_private[0], &c, sizeof(c)));
138 if (n != sizeof(c)) {
139 printk(UM_KERN_ERR "update_thread : write failed, err = %d\n",
140 errno);
141 goto fail;
142 }
143
144 CATCH_EINTR(n = read(sigio_private[0], &c, sizeof(c)));
145 if (n != sizeof(c)) {
146 printk(UM_KERN_ERR "update_thread : read failed, err = %d\n",
147 errno);
148 goto fail;
149 }
150
151 um_set_signals_trace(flags);
152 return;
153 fail:
154 /* Critical section start */
155 if (write_sigio_pid != -1) {
156 os_kill_process(write_sigio_pid, 1);
157 free_stack(write_sigio_stack, 0);
158 }
159 write_sigio_pid = -1;
160 close(sigio_private[0]);
161 close(sigio_private[1]);
162 close(write_sigio_fds[0]);
163 close(write_sigio_fds[1]);
164 /* Critical section end */
165 um_set_signals_trace(flags);
166}
167
168int __add_sigio_fd(int fd)
169{
170 struct pollfd *p;
171 int err, i, n;
172
173 for (i = 0; i < all_sigio_fds.used; i++) {
174 if (all_sigio_fds.poll[i].fd == fd)
175 break;
176 }
177 if (i == all_sigio_fds.used)
178 return -ENOSPC;
179
180 p = &all_sigio_fds.poll[i];
181
182 for (i = 0; i < current_poll.used; i++) {
183 if (current_poll.poll[i].fd == fd)
184 return 0;
185 }
186
187 n = current_poll.used;
188 err = need_poll(&next_poll, n + 1);
189 if (err)
190 return err;
191
192 memcpy(next_poll.poll, current_poll.poll,
193 current_poll.used * sizeof(struct pollfd));
194 next_poll.poll[n] = *p;
195 next_poll.used = n + 1;
196 update_thread();
197
198 return 0;
199}
200
201
202int add_sigio_fd(int fd)
203{
204 int err;
205
206 sigio_lock();
207 err = __add_sigio_fd(fd);
208 sigio_unlock();
209
210 return err;
211}
212
213int __ignore_sigio_fd(int fd)
214{
215 struct pollfd *p;
216 int err, i, n = 0;
217
218 /*
219 * This is called from exitcalls elsewhere in UML - if
220 * sigio_cleanup has already run, then update_thread will hang
221 * or fail because the thread is no longer running.
222 */
223 if (write_sigio_pid == -1)
224 return -EIO;
225
226 for (i = 0; i < current_poll.used; i++) {
227 if (current_poll.poll[i].fd == fd)
228 break;
229 }
230 if (i == current_poll.used)
231 return -ENOENT;
232
233 err = need_poll(&next_poll, current_poll.used - 1);
234 if (err)
235 return err;
236
237 for (i = 0; i < current_poll.used; i++) {
238 p = ¤t_poll.poll[i];
239 if (p->fd != fd)
240 next_poll.poll[n++] = *p;
241 }
242 next_poll.used = current_poll.used - 1;
243
244 update_thread();
245
246 return 0;
247}
248
249int ignore_sigio_fd(int fd)
250{
251 int err;
252
253 sigio_lock();
254 err = __ignore_sigio_fd(fd);
255 sigio_unlock();
256
257 return err;
258}
259
260static struct pollfd *setup_initial_poll(int fd)
261{
262 struct pollfd *p;
263
264 p = uml_kmalloc(sizeof(struct pollfd), UM_GFP_KERNEL);
265 if (p == NULL) {
266 printk(UM_KERN_ERR "setup_initial_poll : failed to allocate "
267 "poll\n");
268 return NULL;
269 }
270 *p = ((struct pollfd) { .fd = fd,
271 .events = POLLIN,
272 .revents = 0 });
273 return p;
274}
275
276static void write_sigio_workaround(void)
277{
278 struct pollfd *p;
279 int err;
280 int l_write_sigio_fds[2];
281 int l_sigio_private[2];
282 int l_write_sigio_pid;
283
284 /* We call this *tons* of times - and most ones we must just fail. */
285 sigio_lock();
286 l_write_sigio_pid = write_sigio_pid;
287 sigio_unlock();
288
289 if (l_write_sigio_pid != -1)
290 return;
291
292 err = os_pipe(l_write_sigio_fds, 1, 1);
293 if (err < 0) {
294 printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 1 failed, "
295 "err = %d\n", -err);
296 return;
297 }
298 err = os_pipe(l_sigio_private, 1, 1);
299 if (err < 0) {
300 printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 2 failed, "
301 "err = %d\n", -err);
302 goto out_close1;
303 }
304
305 p = setup_initial_poll(l_sigio_private[1]);
306 if (!p)
307 goto out_close2;
308
309 sigio_lock();
310
311 /*
312 * Did we race? Don't try to optimize this, please, it's not so likely
313 * to happen, and no more than once at the boot.
314 */
315 if (write_sigio_pid != -1)
316 goto out_free;
317
318 current_poll = ((struct pollfds) { .poll = p,
319 .used = 1,
320 .size = 1 });
321
322 if (write_sigio_irq(l_write_sigio_fds[0]))
323 goto out_clear_poll;
324
325 memcpy(write_sigio_fds, l_write_sigio_fds, sizeof(l_write_sigio_fds));
326 memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private));
327
328 write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
329 CLONE_FILES | CLONE_VM,
330 &write_sigio_stack);
331
332 if (write_sigio_pid < 0)
333 goto out_clear;
334
335 sigio_unlock();
336 return;
337
338out_clear:
339 write_sigio_pid = -1;
340 write_sigio_fds[0] = -1;
341 write_sigio_fds[1] = -1;
342 sigio_private[0] = -1;
343 sigio_private[1] = -1;
344out_clear_poll:
345 current_poll = ((struct pollfds) { .poll = NULL,
346 .size = 0,
347 .used = 0 });
348out_free:
349 sigio_unlock();
350 kfree(p);
351out_close2:
352 close(l_sigio_private[0]);
353 close(l_sigio_private[1]);
354out_close1:
355 close(l_write_sigio_fds[0]);
356 close(l_write_sigio_fds[1]);
357}
358
359void sigio_broken(int fd)
360{
361 int err;
362
363 write_sigio_workaround();
364
365 sigio_lock();
366 err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1);
367 if (err) {
368 printk(UM_KERN_ERR "maybe_sigio_broken - failed to add pollfd "
369 "for descriptor %d\n", fd);
370 goto out;
371 }
372
373 all_sigio_fds.poll[all_sigio_fds.used++] =
374 ((struct pollfd) { .fd = fd,
375 .events = POLLIN,
376 .revents = 0 });
377out:
378 sigio_unlock();
379}
380
381/* Changed during early boot */
382static int pty_output_sigio;
383
384void maybe_sigio_broken(int fd)
385{
386 if (!isatty(fd))
387 return;
388
389 if (pty_output_sigio)
390 return;
391
392 sigio_broken(fd);
393}
394
395static void sigio_cleanup(void)
396{
397 if (write_sigio_pid == -1)
398 return;
399
400 os_kill_process(write_sigio_pid, 1);
401 free_stack(write_sigio_stack, 0);
402 write_sigio_pid = -1;
403}
404
405__uml_exitcall(sigio_cleanup);
406
407/* Used as a flag during SIGIO testing early in boot */
408static int got_sigio;
409
410static void __init handler(int sig)
411{
412 got_sigio = 1;
413}
414
415struct openpty_arg {
416 int master;
417 int slave;
418 int err;
419};
420
421static void openpty_cb(void *arg)
422{
423 struct openpty_arg *info = arg;
424
425 info->err = 0;
426 if (openpty(&info->master, &info->slave, NULL, NULL, NULL))
427 info->err = -errno;
428}
429
430static int async_pty(int master, int slave)
431{
432 int flags;
433
434 flags = fcntl(master, F_GETFL);
435 if (flags < 0)
436 return -errno;
437
438 if ((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
439 (fcntl(master, F_SETOWN, os_getpid()) < 0))
440 return -errno;
441
442 if ((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
443 return -errno;
444
445 return 0;
446}
447
448static void __init check_one_sigio(void (*proc)(int, int))
449{
450 struct sigaction old, new;
451 struct openpty_arg pty = { .master = -1, .slave = -1 };
452 int master, slave, err;
453
454 initial_thread_cb(openpty_cb, &pty);
455 if (pty.err) {
456 printk(UM_KERN_ERR "check_one_sigio failed, errno = %d\n",
457 -pty.err);
458 return;
459 }
460
461 master = pty.master;
462 slave = pty.slave;
463
464 if ((master == -1) || (slave == -1)) {
465 printk(UM_KERN_ERR "check_one_sigio failed to allocate a "
466 "pty\n");
467 return;
468 }
469
470 /* Not now, but complain so we now where we failed. */
471 err = raw(master);
472 if (err < 0) {
473 printk(UM_KERN_ERR "check_one_sigio : raw failed, errno = %d\n",
474 -err);
475 return;
476 }
477
478 err = async_pty(master, slave);
479 if (err < 0) {
480 printk(UM_KERN_ERR "check_one_sigio : sigio_async failed, "
481 "err = %d\n", -err);
482 return;
483 }
484
485 if (sigaction(SIGIO, NULL, &old) < 0) {
486 printk(UM_KERN_ERR "check_one_sigio : sigaction 1 failed, "
487 "errno = %d\n", errno);
488 return;
489 }
490
491 new = old;
492 new.sa_handler = handler;
493 if (sigaction(SIGIO, &new, NULL) < 0) {
494 printk(UM_KERN_ERR "check_one_sigio : sigaction 2 failed, "
495 "errno = %d\n", errno);
496 return;
497 }
498
499 got_sigio = 0;
500 (*proc)(master, slave);
501
502 close(master);
503 close(slave);
504
505 if (sigaction(SIGIO, &old, NULL) < 0)
506 printk(UM_KERN_ERR "check_one_sigio : sigaction 3 failed, "
507 "errno = %d\n", errno);
508}
509
510static void tty_output(int master, int slave)
511{
512 int n;
513 char buf[512];
514
515 printk(UM_KERN_INFO "Checking that host ptys support output SIGIO...");
516
517 memset(buf, 0, sizeof(buf));
518
519 while (write(master, buf, sizeof(buf)) > 0) ;
520 if (errno != EAGAIN)
521 printk(UM_KERN_ERR "tty_output : write failed, errno = %d\n",
522 errno);
523 while (((n = read(slave, buf, sizeof(buf))) > 0) &&
524 !({ barrier(); got_sigio; }))
525 ;
526
527 if (got_sigio) {
528 printk(UM_KERN_CONT "Yes\n");
529 pty_output_sigio = 1;
530 } else if (n == -EAGAIN)
531 printk(UM_KERN_CONT "No, enabling workaround\n");
532 else
533 printk(UM_KERN_CONT "tty_output : read failed, err = %d\n", n);
534}
535
536static void __init check_sigio(void)
537{
538 if ((access("/dev/ptmx", R_OK) < 0) &&
539 (access("/dev/ptyp0", R_OK) < 0)) {
540 printk(UM_KERN_WARNING "No pseudo-terminals available - "
541 "skipping pty SIGIO check\n");
542 return;
543 }
544 check_one_sigio(tty_output);
545}
546
547/* Here because it only does the SIGIO testing for now */
548void __init os_check_bugs(void)
549{
550 check_sigio();
551}