xref: /freebsd/sys/compat/lindebugfs/lindebugfs.c (revision 3521cce445d4238aa425629c5fcc1c723b427d3e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2016-2018, Matthew Macy <mmacy@freebsd.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  */
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/queue.h>
32 #include <sys/blist.h>
33 #include <sys/conf.h>
34 #include <sys/exec.h>
35 #include <sys/filedesc.h>
36 #include <sys/kernel.h>
37 #include <sys/linker.h>
38 #include <sys/malloc.h>
39 #include <sys/mount.h>
40 #include <sys/mutex.h>
41 #include <sys/proc.h>
42 #include <sys/resourcevar.h>
43 #include <sys/sbuf.h>
44 #include <sys/smp.h>
45 #include <sys/socket.h>
46 #include <sys/vnode.h>
47 #include <sys/bus.h>
48 #include <sys/pciio.h>
49 
50 #include <dev/pci/pcivar.h>
51 #include <dev/pci/pcireg.h>
52 
53 #include <net/if.h>
54 
55 #include <vm/vm.h>
56 #include <vm/pmap.h>
57 #include <vm/vm_map.h>
58 #include <vm/vm_param.h>
59 #include <vm/vm_object.h>
60 #include <vm/swap_pager.h>
61 
62 #include <machine/bus.h>
63 
64 #include <compat/linux/linux_ioctl.h>
65 #include <compat/linux/linux_mib.h>
66 #include <compat/linux/linux_util.h>
67 #include <fs/pseudofs/pseudofs.h>
68 
69 #include <asm/atomic.h>
70 #include <linux/compat.h>
71 #include <linux/debugfs.h>
72 #include <linux/fs.h>
73 #include <linux/device.h>
74 
75 MALLOC_DEFINE(M_DFSINT, "debugfsint", "Linux debugfs internal");
76 
77 static struct pfs_node *debugfs_root;
78 
79 #define DM_SYMLINK 0x1
80 #define DM_DIR 0x2
81 #define DM_FILE 0x3
82 
83 struct dentry_meta {
84 	struct dentry dm_dnode;
85 	const struct file_operations *dm_fops;
86 	void *dm_data;
87 	umode_t dm_mode;
88 	int dm_type;
89 };
90 
91 static int
92 debugfs_attr(PFS_ATTR_ARGS)
93 {
94 	struct dentry_meta *dm;
95 
96 	dm = pn->pn_data;
97 
98 	vap->va_mode = dm->dm_mode;
99 	return (0);
100 }
101 
102 static int
103 debugfs_destroy(PFS_DESTROY_ARGS)
104 {
105 	struct dentry_meta *dm;
106 
107 	dm = pn->pn_data;
108 	if (dm != NULL && dm->dm_type == DM_SYMLINK)
109 		free(dm->dm_data, M_DFSINT);
110 
111 	free(dm, M_DFSINT);
112 	return (0);
113 }
114 
115 static int
116 debugfs_fill(PFS_FILL_ARGS)
117 {
118 	struct dentry_meta *d;
119 	struct linux_file lf = {};
120 	struct vnode vn;
121 	struct iovec *iov;
122 	size_t cnt, orig_resid;
123 	ssize_t rc;
124 	off_t off;
125 
126 	/* Linux file operations assume a pointer to a user buffer. */
127 	if (uio->uio_segflg != UIO_USERSPACE)
128 		return (EOPNOTSUPP);
129 
130 	if ((rc = linux_set_current_flags(curthread, M_NOWAIT)))
131 		return (rc);
132 
133 	d = pn->pn_data;
134 	vn.v_data = d->dm_data;
135 
136 	rc = d->dm_fops->open(&vn, &lf);
137 	if (rc < 0) {
138 #ifdef INVARIANTS
139 		printf("%s:%d open failed with %zd\n", __func__, __LINE__, rc);
140 #endif
141 		return (-rc);
142 	}
143 
144 	off = uio->uio_offset;
145 	orig_resid = uio->uio_resid;
146 	while (uio->uio_resid > 0) {
147 		KASSERT(uio->uio_iovcnt > 0,
148 		    ("%s: uio %p iovcnt underflow", __func__, uio));
149 
150 		iov = uio->uio_iov;
151 		cnt = iov->iov_len;
152 		if (cnt == 0) {
153 			uio->uio_iov++;
154 			uio->uio_iovcnt--;
155 			continue;
156 		}
157 		if (cnt > uio->uio_resid)
158 			cnt = uio->uio_resid;
159 
160 		switch (uio->uio_rw) {
161 		case UIO_READ:
162 			if (d->dm_fops->read != NULL)
163 				rc = d->dm_fops->read(&lf, iov->iov_base, cnt,
164 				    &off);
165 			else
166 				rc = -ENODEV;
167 			break;
168 		case UIO_WRITE:
169 			if (d->dm_fops->write != NULL)
170 				rc = d->dm_fops->write(&lf, iov->iov_base, cnt,
171 				    &off);
172 			else
173 				rc = -ENODEV;
174 			break;
175 		}
176 
177 		if (rc <= 0)
178 			break;
179 
180 		iov->iov_base = (char *)iov->iov_base + rc;
181 		iov->iov_len -= rc;
182 		uio->uio_resid -= rc;
183 		uio->uio_offset = off;
184 	}
185 
186 	if (d->dm_fops->release)
187 		d->dm_fops->release(&vn, &lf);
188 
189 	/* Return success for short operations. */
190 	if (orig_resid != uio->uio_resid)
191 		rc = 0;
192 
193 	if (rc < 0) {
194 #ifdef INVARIANTS
195 		printf("%s:%d %s failed with %zd\n", __func__, __LINE__,
196 		    (uio->uio_rw == UIO_READ) ? "read" : "write", rc);
197 #endif
198 		return (-rc);
199 	}
200 	return (0);
201 }
202 
203 static int
204 debugfs_fill_data(PFS_FILL_ARGS)
205 {
206 	struct dentry_meta *dm;
207 
208 	dm = pn->pn_data;
209 	sbuf_printf(sb, "%s", (char *)dm->dm_data);
210 	return (0);
211 }
212 
213 struct dentry *
214 debugfs_create_file(const char *name, umode_t mode,
215     struct dentry *parent, void *data,
216     const struct file_operations *fops)
217 {
218 	struct dentry_meta *dm;
219 	struct dentry *dnode;
220 	struct pfs_node *pnode;
221 	int flags;
222 
223 	dm = malloc(sizeof(*dm), M_DFSINT, M_NOWAIT | M_ZERO);
224 	if (dm == NULL)
225 		return (NULL);
226 	dnode = &dm->dm_dnode;
227 	dm->dm_fops = fops;
228 	dm->dm_data = data;
229 	dm->dm_mode = mode;
230 	dm->dm_type = DM_FILE;
231 	if (parent != NULL)
232 		pnode = parent->d_pfs_node;
233 	else
234 		pnode = debugfs_root;
235 
236 	flags = fops->write ? PFS_RDWR : PFS_RD;
237 	pfs_create_file(pnode, &dnode->d_pfs_node, name, debugfs_fill,
238 	    debugfs_attr, NULL, debugfs_destroy, flags | PFS_RAW | PFS_NOWAIT);
239 	if (dnode->d_pfs_node == NULL) {
240 		free(dm, M_DFSINT);
241 		return (NULL);
242 	}
243 	dnode->d_pfs_node->pn_data = dm;
244 
245 	return (dnode);
246 }
247 
248 struct dentry *
249 debugfs_create_file_size(const char *name, umode_t mode,
250     struct dentry *parent, void *data,
251     const struct file_operations *fops,
252     loff_t file_size __unused)
253 {
254 
255 	return debugfs_create_file(name, mode, parent, data, fops);
256 }
257 
258 /*
259  * NOTE: Files created with the _unsafe moniker will not be protected from
260  * debugfs core file removals. It is the responsibility of @fops to protect
261  * its file using debugfs_file_get() and debugfs_file_put().
262  *
263  * FreeBSD's LinuxKPI lindebugfs does not perform file removals at the time
264  * of writing. Therefore there is no difference between functions with _unsafe
265  * and functions without _unsafe when using lindebugfs. Functions with _unsafe
266  * exist only for Linux compatibility.
267  */
268 struct dentry *
269 debugfs_create_file_unsafe(const char *name, umode_t mode,
270     struct dentry *parent, void *data,
271     const struct file_operations *fops)
272 {
273 
274 	return (debugfs_create_file(name, mode, parent, data, fops));
275 }
276 
277 struct dentry *
278 debugfs_create_mode_unsafe(const char *name, umode_t mode,
279     struct dentry *parent, void *data,
280     const struct file_operations *fops,
281     const struct file_operations *fops_ro,
282     const struct file_operations *fops_wo)
283 {
284 	umode_t read = mode & S_IRUGO;
285 	umode_t write = mode & S_IWUGO;
286 
287 	if (read && !write)
288 		return (debugfs_create_file_unsafe(name, mode, parent, data, fops_ro));
289 
290 	if (write && !read)
291 		return (debugfs_create_file_unsafe(name, mode, parent, data, fops_wo));
292 
293 	return (debugfs_create_file_unsafe(name, mode, parent, data, fops));
294 }
295 
296 struct dentry *
297 debugfs_create_dir(const char *name, struct dentry *parent)
298 {
299 	struct dentry_meta *dm;
300 	struct dentry *dnode;
301 	struct pfs_node *pnode;
302 
303 	if (name == NULL)
304 		return (NULL);
305 
306 	dm = malloc(sizeof(*dm), M_DFSINT, M_NOWAIT | M_ZERO);
307 	if (dm == NULL)
308 		return (NULL);
309 	dnode = &dm->dm_dnode;
310 	dm->dm_mode = 0700;
311 	dm->dm_type = DM_DIR;
312 	if (parent != NULL)
313 		pnode = parent->d_pfs_node;
314 	else
315 		pnode = debugfs_root;
316 
317 	pfs_create_dir(pnode, &dnode->d_pfs_node, name, debugfs_attr, NULL,
318 	    debugfs_destroy, PFS_RD | PFS_NOWAIT);
319 	if (dnode->d_pfs_node == NULL) {
320 		free(dm, M_DFSINT);
321 		return (NULL);
322 	}
323 	dnode->d_pfs_node->pn_data = dm;
324 	return (dnode);
325 }
326 
327 struct dentry *
328 debugfs_create_symlink(const char *name, struct dentry *parent,
329     const char *dest)
330 {
331 	struct dentry_meta *dm;
332 	struct dentry *dnode;
333 	struct pfs_node *pnode;
334 	void *data;
335 
336 	data = strdup_flags(dest, M_DFSINT, M_NOWAIT);
337 	if (data == NULL)
338 		return (NULL);
339 	dm = malloc(sizeof(*dm), M_DFSINT, M_NOWAIT | M_ZERO);
340 	if (dm == NULL)
341 		goto fail1;
342 	dnode = &dm->dm_dnode;
343 	dm->dm_mode = 0700;
344 	dm->dm_type = DM_SYMLINK;
345 	dm->dm_data = data;
346 	if (parent != NULL)
347 		pnode = parent->d_pfs_node;
348 	else
349 		pnode = debugfs_root;
350 
351 	pfs_create_link(pnode, &dnode->d_pfs_node, name, &debugfs_fill_data,
352 	    NULL, NULL, NULL, PFS_NOWAIT);
353 	if (dnode->d_pfs_node == NULL)
354 		goto fail;
355 	dnode->d_pfs_node->pn_data = dm;
356 	return (dnode);
357  fail:
358 	free(dm, M_DFSINT);
359  fail1:
360 	free(data, M_DFSINT);
361 	return (NULL);
362 }
363 
364 struct dentry *
365 debugfs_lookup(const char *name, struct dentry *parent)
366 {
367 	struct dentry_meta *dm;
368 	struct dentry *dnode;
369 	struct pfs_node *pnode;
370 
371 	pnode = pfs_find_node(parent->d_pfs_node, name);
372 	if (pnode == NULL)
373 		return (NULL);
374 
375 	dm = (struct dentry_meta *)pnode->pn_data;
376 	dnode = &dm->dm_dnode;
377 
378 	return (dnode);
379 }
380 
381 void
382 debugfs_remove(struct dentry *dnode)
383 {
384 	if (dnode == NULL)
385 		return;
386 
387 	pfs_destroy(dnode->d_pfs_node);
388 }
389 
390 void
391 debugfs_remove_recursive(struct dentry *dnode)
392 {
393 	if (dnode == NULL)
394 		return;
395 
396 	pfs_destroy(dnode->d_pfs_node);
397 }
398 
399 static int
400 debugfs_bool_get(void *data, uint64_t *ullval)
401 {
402 	bool *bval = data;
403 
404 	if (*bval)
405 		*ullval = 1;
406 	else
407 		*ullval = 0;
408 
409 	return (0);
410 }
411 
412 static int
413 debugfs_bool_set(void *data, uint64_t ullval)
414 {
415 	bool *bval = data;
416 
417 	if (ullval)
418 		*bval = 1;
419 	else
420 		*bval = 0;
421 
422 	return (0);
423 }
424 
425 DEFINE_DEBUGFS_ATTRIBUTE(fops_bool, debugfs_bool_get, debugfs_bool_set, "%llu\n");
426 DEFINE_DEBUGFS_ATTRIBUTE(fops_bool_ro, debugfs_bool_get, NULL, "%llu\n");
427 DEFINE_DEBUGFS_ATTRIBUTE(fops_bool_wo, NULL, debugfs_bool_set, "%llu\n");
428 
429 void
430 debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent, bool *value)
431 {
432 
433 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
434 	    &fops_bool_ro, &fops_bool_wo);
435 }
436 
437 
438 static int
439 debugfs_u8_get(void *data, uint64_t *value)
440 {
441 	uint8_t *u8data = data;
442 	*value = *u8data;
443 	return (0);
444 }
445 
446 static int
447 debugfs_u8_set(void *data, uint64_t value)
448 {
449 	uint8_t *u8data = data;
450 	*u8data = (uint8_t)value;
451 	return (0);
452 }
453 
454 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%u\n");
455 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%u\n");
456 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%u\n");
457 
458 void
459 debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent, uint8_t *value)
460 {
461 
462 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
463 	    &fops_u8_ro, &fops_u8_wo);
464 }
465 
466 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%016llx\n");
467 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%016llx\n");
468 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%016llx\n");
469 
470 void
471 debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent, uint8_t *value)
472 {
473 
474 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
475 	    &fops_x8_ro, &fops_x8_wo);
476 }
477 
478 
479 static int
480 debugfs_u16_get(void *data, uint64_t *value)
481 {
482 	uint16_t *u16data = data;
483 	*value = *u16data;
484 	return (0);
485 }
486 
487 static int
488 debugfs_u16_set(void *data, uint64_t value)
489 {
490 	uint16_t *u16data = data;
491 	*u16data = (uint16_t)value;
492 	return (0);
493 }
494 
495 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%u\n");
496 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%u\n");
497 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%u\n");
498 
499 void
500 debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent, uint16_t *value)
501 {
502 
503 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
504 	    &fops_u16_ro, &fops_u16_wo);
505 }
506 
507 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%016llx\n");
508 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%016llx\n");
509 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%016llx\n");
510 
511 void
512 debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent, uint16_t *value)
513 {
514 
515 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
516 	    &fops_x16_ro, &fops_x16_wo);
517 }
518 
519 
520 static int
521 debugfs_u32_get(void *data, uint64_t *value)
522 {
523 	uint32_t *u32data = data;
524 	*value = *u32data;
525 	return (0);
526 }
527 
528 static int
529 debugfs_u32_set(void *data, uint64_t value)
530 {
531 	uint32_t *u32data = data;
532 	*u32data = (uint32_t)value;
533 	return (0);
534 }
535 
536 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%u\n");
537 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%u\n");
538 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%u\n");
539 
540 void
541 debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent, uint32_t *value)
542 {
543 
544 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
545 	    &fops_u32_ro, &fops_u32_wo);
546 }
547 
548 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%016llx\n");
549 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%016llx\n");
550 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%016llx\n");
551 
552 void
553 debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent, uint32_t *value)
554 {
555 
556 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
557 	    &fops_x32_ro, &fops_x32_wo);
558 }
559 
560 
561 static int
562 debugfs_u64_get(void *data, uint64_t *value)
563 {
564 	uint64_t *u64data = data;
565 	*value = *u64data;
566 	return (0);
567 }
568 
569 static int
570 debugfs_u64_set(void *data, uint64_t value)
571 {
572 	uint64_t *u64data = data;
573 	*u64data = (uint64_t)value;
574 	return (0);
575 }
576 
577 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%u\n");
578 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%u\n");
579 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%u\n");
580 
581 void
582 debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, uint64_t *value)
583 {
584 
585 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
586 	    &fops_u64_ro, &fops_u64_wo);
587 }
588 
589 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
590 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
591 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
592 
593 void
594 debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent, uint64_t *value)
595 {
596 
597 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
598 	    &fops_x64_ro, &fops_x64_wo);
599 }
600 
601 
602 static int
603 debugfs_ulong_get(void *data, uint64_t *value)
604 {
605 	uint64_t *uldata = data;
606 	*value = *uldata;
607 	return (0);
608 }
609 
610 static int
611 debugfs_ulong_set(void *data, uint64_t value)
612 {
613 	uint64_t *uldata = data;
614 	*uldata = value;
615 	return (0);
616 }
617 
618 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set, "%llu\n");
619 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
620 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
621 
622 void
623 debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent, unsigned long *value)
624 {
625 
626 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
627 	    &fops_ulong_ro, &fops_ulong_wo);
628 }
629 
630 
631 static int
632 debugfs_atomic_t_get(void *data, uint64_t *value)
633 {
634 	atomic_t *atomic_data = data;
635 	*value = atomic_read(atomic_data);
636 	return (0);
637 }
638 
639 static int
640 debugfs_atomic_t_set(void *data, uint64_t value)
641 {
642 	atomic_t *atomic_data = data;
643 	atomic_set(atomic_data, (int)value);
644 	return (0);
645 }
646 
647 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, debugfs_atomic_t_set, "%d\n");
648 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%d\n");
649 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%d\n");
650 
651 void
652 debugfs_create_atomic_t(const char *name, umode_t mode, struct dentry *parent, atomic_t *value)
653 {
654 
655 	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
656 	    &fops_atomic_t_ro, &fops_atomic_t_wo);
657 }
658 
659 
660 static int
661 fops_str_open(struct inode *inode, struct file *filp)
662 {
663 
664 	return (simple_open(inode, filp));
665 }
666 
667 static ssize_t
668 fops_str_read(struct file *filp, char __user *ubuf, size_t read_size,
669     loff_t *ppos)
670 {
671 	ssize_t ret;
672 	char *str, *str_with_newline;
673 	size_t str_len, str_with_newline_len;
674 
675 	if (filp->private_data == NULL)
676 		return (-EINVAL);
677 
678 	str = *(char **)filp->private_data;
679 	str_len = strlen(str);
680 
681 	/*
682 	 * `str_with_newline` is terminated with a newline, but is not
683 	 * NUL-terminated.
684 	 */
685 	str_with_newline_len = str_len + 1;
686 	str_with_newline = kmalloc(str_with_newline_len, GFP_KERNEL);
687 	if (str_with_newline == NULL)
688 		return (-ENOMEM);
689 
690 	strncpy(str_with_newline, str, str_len);
691 	str_with_newline[str_len] = '\n';
692 
693 	ret = simple_read_from_buffer(ubuf, read_size, ppos,
694 	    str_with_newline, str_with_newline_len);
695 
696 	kfree(str_with_newline);
697 
698 	return (ret);
699 }
700 
701 static ssize_t
702 fops_str_write(struct file *filp, const char __user *buf, size_t write_size,
703     loff_t *ppos)
704 {
705 	char *old, *new;
706 	size_t old_len, new_len;
707 
708 	if (filp->private_data == NULL)
709 		return (-EINVAL);
710 
711 	old = *(char **)filp->private_data;
712 	new = NULL;
713 
714 	/*
715 	 * We enforce concatenation of the newly written value to the existing
716 	 * value.
717 	 */
718 	old_len = strlen(old);
719 	if (*ppos && *ppos != old_len)
720 		return (-EINVAL);
721 
722 	new_len = old_len + write_size;
723 	if (new_len + 1 > PAGE_SIZE)
724 		return (-E2BIG);
725 
726 	new = kmalloc(new_len + 1, GFP_KERNEL);
727 	if (new == NULL)
728 		return (-ENOMEM);
729 
730 	memcpy(new, old, old_len);
731 	if (copy_from_user(new + old_len, buf, write_size) != 0) {
732 		kfree(new);
733 		return (-EFAULT);
734 	}
735 
736 	new[new_len] = '\0';
737 	strim(new);
738 
739 	filp->private_data = &new;
740 
741 	kfree(old);
742 
743 	return (write_size);
744 }
745 
746 static const struct file_operations fops_str = {
747 	.owner = THIS_MODULE,
748 	.open = fops_str_open,
749 	.read = fops_str_read,
750 	.write = fops_str_write,
751 	.llseek = no_llseek
752 };
753 static const struct file_operations fops_str_ro = {
754 	.owner = THIS_MODULE,
755 	.open = fops_str_open,
756 	.read = fops_str_read,
757 	.llseek = no_llseek
758 };
759 static const struct file_operations fops_str_wo = {
760 	.owner = THIS_MODULE,
761 	.open = fops_str_open,
762 	.write = fops_str_write,
763 	.llseek = no_llseek
764 };
765 
766 void
767 debugfs_create_str(const char *name, umode_t mode, struct dentry *parent,
768     char **value)
769 {
770 	debugfs_create_mode_unsafe(name, mode, parent, value,
771 	    &fops_str, &fops_str_ro, &fops_str_wo);
772 }
773 
774 
775 static ssize_t
776 fops_blob_read(struct file *filp, char __user *ubuf, size_t read_size, loff_t *ppos)
777 {
778 	struct debugfs_blob_wrapper *blob;
779 
780 	blob = filp->private_data;
781 	if (blob == NULL)
782 		return (-EINVAL);
783 	if (blob->size == 0 || blob->data == NULL)
784 		return (-EINVAL);
785 
786 	return (simple_read_from_buffer(ubuf, read_size, ppos, blob->data, blob->size));
787 }
788 
789 static int
790 fops_blob_open(struct inode *inode, struct file *filp)
791 {
792 
793 	return (simple_open(inode, filp));
794 }
795 
796 static const struct file_operations __fops_blob_ro = {
797 	.owner = THIS_MODULE,
798 	.open = fops_blob_open,
799 	.read = fops_blob_read,
800 	.llseek = no_llseek
801 };
802 
803 struct dentry *
804 debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent,
805     struct debugfs_blob_wrapper *value)
806 {
807 	/* Blobs are read-only. */
808 	return (debugfs_create_file(name, mode & 0444, parent, value, &__fops_blob_ro));
809 }
810 
811 /* ---------------------------------------------------------------------------- */
812 /* This should be migrated to ??? */
813 
814 struct debugfs_devm_seqfile {
815 	struct device *dev;
816 	int (*readfunc)(struct seq_file *, void *);
817 };
818 
819 static int
820 debugfs_devm_seqfile_open(struct inode *inode, struct linux_file *f)
821 {
822 	struct debugfs_devm_seqfile *s;
823 
824 	s = inode->i_private;
825 	return (single_open(f, s->readfunc, s->dev));
826 }
827 
828 static const struct file_operations debugfs_devm_seqfile_ops = {
829 	.owner			= THIS_MODULE,
830 	.open			= debugfs_devm_seqfile_open,
831 	.read			= seq_read,
832 	.llseek			= seq_lseek,
833 	.release		= single_release,
834 };
835 
836 void
837 debugfs_create_devm_seqfile(struct device *dev, const char *name,
838     struct dentry *d, int (*readfunc)(struct seq_file *m, void *arg))
839 {
840 	struct debugfs_devm_seqfile *s;
841 
842 	s = devm_kzalloc(dev, sizeof(*s), GFP_KERNEL);
843 	if (s == NULL)
844 		return;
845 
846 	s->dev = dev;
847 	s->readfunc = readfunc;
848 
849 	debugfs_create_file(name, 0444, d, s, &debugfs_devm_seqfile_ops);
850 }
851 /* ---------------------------------------------------------------------------- */
852 
853 static int
854 lindebugfs_init(PFS_INIT_ARGS)
855 {
856 
857 	debugfs_root = pi->pi_root;
858 
859 	(void)debugfs_create_symlink("kcov", NULL, "/dev/kcov");
860 
861 	return (0);
862 }
863 
864 static int
865 lindebugfs_uninit(PFS_INIT_ARGS)
866 {
867 
868 	return (0);
869 }
870 
871 PSEUDOFS(lindebugfs, 1, VFCF_JAIL);
872 MODULE_DEPEND(lindebugfs, linuxkpi, 1, 1, 1);
873