1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
4 * Copyright (C) 2007 The Regents of the University of California.
5 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
6 * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
7 * UCRL-CODE-235197
8 *
9 * This file is part of the SPL, Solaris Porting Layer.
10 *
11 * The SPL is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
15 *
16 * The SPL is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 * for more details.
20 *
21 * You should have received a copy of the GNU General Public License along
22 * with the SPL. If not, see <http://www.gnu.org/licenses/>.
23 *
24 * Solaris Porting Layer (SPL) Generic Implementation.
25 */
26
27 #include <sys/isa_defs.h>
28 #include <sys/sysmacros.h>
29 #include <sys/systeminfo.h>
30 #include <sys/vmsystm.h>
31 #include <sys/kmem.h>
32 #include <sys/kmem_cache.h>
33 #include <sys/vmem.h>
34 #include <sys/mutex.h>
35 #include <sys/rwlock.h>
36 #include <sys/taskq.h>
37 #include <sys/tsd.h>
38 #include <sys/zmod.h>
39 #include <sys/debug.h>
40 #include <sys/proc.h>
41 #include <sys/kstat.h>
42 #include <sys/file.h>
43 #include <sys/sunddi.h>
44 #include <linux/ctype.h>
45 #include <sys/disp.h>
46 #include <sys/random.h>
47 #include <sys/string.h>
48 #include <linux/kmod.h>
49 #include <linux/mod_compat.h>
50 #include <sys/cred.h>
51 #include <sys/vnode.h>
52 #include <sys/misc.h>
53 #include <linux/mod_compat.h>
54
55 unsigned long spl_hostid = 0;
56 EXPORT_SYMBOL(spl_hostid);
57
58 module_param(spl_hostid, ulong, 0644);
59 MODULE_PARM_DESC(spl_hostid, "The system hostid.");
60
61 proc_t p0;
62 EXPORT_SYMBOL(p0);
63
64 /*
65 * xoshiro256++ 1.0 PRNG by David Blackman and Sebastiano Vigna
66 *
67 * "Scrambled Linear Pseudorandom Number Generators∗"
68 * https://vigna.di.unimi.it/ftp/papers/ScrambledLinear.pdf
69 *
70 * random_get_pseudo_bytes() is an API function on Illumos whose sole purpose
71 * is to provide bytes containing random numbers. It is mapped to /dev/urandom
72 * on Illumos, which uses a "FIPS 186-2 algorithm". No user of the SPL's
73 * random_get_pseudo_bytes() needs bytes that are of cryptographic quality, so
74 * we can implement it using a fast PRNG that we seed using Linux' actual
75 * equivalent to random_get_pseudo_bytes(). We do this by providing each CPU
76 * with an independent seed so that all calls to random_get_pseudo_bytes() are
77 * free of atomic instructions.
78 *
79 * A consequence of using a fast PRNG is that using random_get_pseudo_bytes()
80 * to generate words larger than 256 bits will paradoxically be limited to
81 * `2^256 - 1` possibilities. This is because we have a sequence of `2^256 - 1`
82 * 256-bit words and selecting the first will implicitly select the second. If
83 * a caller finds this behavior undesirable, random_get_bytes() should be used
84 * instead.
85 *
86 * XXX: Linux interrupt handlers that trigger within the critical section
87 * formed by `s[3] = xp[3];` and `xp[0] = s[0];` and call this function will
88 * see the same numbers. Nothing in the code currently calls this in an
89 * interrupt handler, so this is considered to be okay. If that becomes a
90 * problem, we could create a set of per-cpu variables for interrupt handlers
91 * and use them when in_interrupt() from linux/preempt_mask.h evaluates to
92 * true.
93 */
94 static void __percpu *spl_pseudo_entropy;
95
96 /*
97 * rotl()/spl_rand_next()/spl_rand_jump() are copied from the following CC-0
98 * licensed file:
99 *
100 * https://prng.di.unimi.it/xoshiro256plusplus.c
101 */
102
rotl(const uint64_t x,int k)103 static inline uint64_t rotl(const uint64_t x, int k)
104 {
105 return ((x << k) | (x >> (64 - k)));
106 }
107
108 static inline uint64_t
spl_rand_next(uint64_t * s)109 spl_rand_next(uint64_t *s)
110 {
111 const uint64_t result = rotl(s[0] + s[3], 23) + s[0];
112
113 const uint64_t t = s[1] << 17;
114
115 s[2] ^= s[0];
116 s[3] ^= s[1];
117 s[1] ^= s[2];
118 s[0] ^= s[3];
119
120 s[2] ^= t;
121
122 s[3] = rotl(s[3], 45);
123
124 return (result);
125 }
126
127 static inline void
spl_rand_jump(uint64_t * s)128 spl_rand_jump(uint64_t *s)
129 {
130 static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba,
131 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
132
133 uint64_t s0 = 0;
134 uint64_t s1 = 0;
135 uint64_t s2 = 0;
136 uint64_t s3 = 0;
137 int i, b;
138 for (i = 0; i < sizeof (JUMP) / sizeof (*JUMP); i++)
139 for (b = 0; b < 64; b++) {
140 if (JUMP[i] & 1ULL << b) {
141 s0 ^= s[0];
142 s1 ^= s[1];
143 s2 ^= s[2];
144 s3 ^= s[3];
145 }
146 (void) spl_rand_next(s);
147 }
148
149 s[0] = s0;
150 s[1] = s1;
151 s[2] = s2;
152 s[3] = s3;
153 }
154
155 int
random_get_pseudo_bytes(uint8_t * ptr,size_t len)156 random_get_pseudo_bytes(uint8_t *ptr, size_t len)
157 {
158 uint64_t *xp, s[4];
159
160 ASSERT(ptr);
161
162 xp = get_cpu_ptr(spl_pseudo_entropy);
163
164 s[0] = xp[0];
165 s[1] = xp[1];
166 s[2] = xp[2];
167 s[3] = xp[3];
168
169 while (len) {
170 union {
171 uint64_t ui64;
172 uint8_t byte[sizeof (uint64_t)];
173 }entropy;
174 int i = MIN(len, sizeof (uint64_t));
175
176 len -= i;
177 entropy.ui64 = spl_rand_next(s);
178
179 /*
180 * xoshiro256++ has low entropy lower bytes, so we copy the
181 * higher order bytes first.
182 */
183 while (i--)
184 #ifdef _ZFS_BIG_ENDIAN
185 *ptr++ = entropy.byte[i];
186 #else
187 *ptr++ = entropy.byte[7 - i];
188 #endif
189 }
190
191 xp[0] = s[0];
192 xp[1] = s[1];
193 xp[2] = s[2];
194 xp[3] = s[3];
195
196 put_cpu_ptr(spl_pseudo_entropy);
197
198 return (0);
199 }
200 EXPORT_SYMBOL(random_get_pseudo_bytes);
201
202 /*
203 * NOTE: The strtoxx behavior is solely based on my reading of the Solaris
204 * ddi_strtol(9F) man page. I have not verified the behavior of these
205 * functions against their Solaris counterparts. It is possible that I
206 * may have misinterpreted the man page or the man page is incorrect.
207 */
208 int ddi_strtol(const char *, char **, int, long *);
209 int ddi_strtoull(const char *, char **, int, unsigned long long *);
210 int ddi_strtoll(const char *, char **, int, long long *);
211
212 #define define_ddi_strtox(type, valtype) \
213 int ddi_strto##type(const char *str, char **endptr, \
214 int base, valtype *result) \
215 { \
216 valtype last_value, value = 0; \
217 char *ptr = (char *)str; \
218 int digit, minus = 0; \
219 \
220 while (strchr(" \t\n\r\f", *ptr)) \
221 ++ptr; \
222 \
223 if (strlen(ptr) == 0) \
224 return (EINVAL); \
225 \
226 switch (*ptr) { \
227 case '-': \
228 minus = 1; \
229 zfs_fallthrough; \
230 case '+': \
231 ++ptr; \
232 break; \
233 } \
234 \
235 /* Auto-detect base based on prefix */ \
236 if (!base) { \
237 if (str[0] == '0') { \
238 if (tolower(str[1]) == 'x' && isxdigit(str[2])) { \
239 base = 16; /* hex */ \
240 ptr += 2; \
241 } else if (str[1] >= '0' && str[1] < '8') { \
242 base = 8; /* octal */ \
243 ptr += 1; \
244 } else { \
245 return (EINVAL); \
246 } \
247 } else { \
248 base = 10; /* decimal */ \
249 } \
250 } \
251 \
252 while (1) { \
253 if (isdigit(*ptr)) \
254 digit = *ptr - '0'; \
255 else if (isalpha(*ptr)) \
256 digit = tolower(*ptr) - 'a' + 10; \
257 else \
258 break; \
259 \
260 if (digit >= base) \
261 break; \
262 \
263 last_value = value; \
264 value = value * base + digit; \
265 if (last_value > value) /* Overflow */ \
266 return (ERANGE); \
267 \
268 ptr++; \
269 } \
270 \
271 *result = minus ? -value : value; \
272 \
273 if (endptr) \
274 *endptr = ptr; \
275 \
276 return (0); \
277 } \
278
279 define_ddi_strtox(l, long)
280 define_ddi_strtox(ull, unsigned long long)
281 define_ddi_strtox(ll, long long)
282
283 EXPORT_SYMBOL(ddi_strtol);
284 EXPORT_SYMBOL(ddi_strtoll);
285 EXPORT_SYMBOL(ddi_strtoull);
286
287 int
ddi_copyin(const void * from,void * to,size_t len,int flags)288 ddi_copyin(const void *from, void *to, size_t len, int flags)
289 {
290 /* Fake ioctl() issued by kernel, 'from' is a kernel address */
291 if (flags & FKIOCTL) {
292 memcpy(to, from, len);
293 return (0);
294 }
295
296 return (copyin(from, to, len));
297 }
298 EXPORT_SYMBOL(ddi_copyin);
299
300 /*
301 * Post a uevent to userspace whenever a new vdev adds to the pool. It is
302 * necessary to sync blkid information with udev, which zed daemon uses
303 * during device hotplug to identify the vdev.
304 */
305 void
spl_signal_kobj_evt(struct block_device * bdev)306 spl_signal_kobj_evt(struct block_device *bdev)
307 {
308 #if defined(HAVE_BDEV_KOBJ) || defined(HAVE_PART_TO_DEV)
309 #ifdef HAVE_BDEV_KOBJ
310 struct kobject *disk_kobj = bdev_kobj(bdev);
311 #else
312 struct kobject *disk_kobj = &part_to_dev(bdev->bd_part)->kobj;
313 #endif
314 if (disk_kobj) {
315 int ret = kobject_uevent(disk_kobj, KOBJ_CHANGE);
316 if (ret) {
317 pr_warn("ZFS: Sending event '%d' to kobject: '%s'"
318 " (%p): failed(ret:%d)\n", KOBJ_CHANGE,
319 kobject_name(disk_kobj), disk_kobj, ret);
320 }
321 }
322 #else
323 /*
324 * This is encountered if neither bdev_kobj() nor part_to_dev() is available
325 * in the kernel - likely due to an API change that needs to be chased down.
326 */
327 #error "Unsupported kernel: unable to get struct kobj from bdev"
328 #endif
329 }
330 EXPORT_SYMBOL(spl_signal_kobj_evt);
331
332 int
ddi_copyout(const void * from,void * to,size_t len,int flags)333 ddi_copyout(const void *from, void *to, size_t len, int flags)
334 {
335 /* Fake ioctl() issued by kernel, 'from' is a kernel address */
336 if (flags & FKIOCTL) {
337 memcpy(to, from, len);
338 return (0);
339 }
340
341 return (copyout(from, to, len));
342 }
343 EXPORT_SYMBOL(ddi_copyout);
344
345 static int
spl_getattr(struct file * filp,struct kstat * stat)346 spl_getattr(struct file *filp, struct kstat *stat)
347 {
348 int rc;
349
350 ASSERT(filp);
351 ASSERT(stat);
352
353 rc = vfs_getattr(&filp->f_path, stat, STATX_BASIC_STATS,
354 AT_STATX_SYNC_AS_STAT);
355 if (rc)
356 return (-rc);
357
358 return (0);
359 }
360
361 /*
362 * Read the unique system identifier from the /etc/hostid file.
363 *
364 * The behavior of /usr/bin/hostid on Linux systems with the
365 * regular eglibc and coreutils is:
366 *
367 * 1. Generate the value if the /etc/hostid file does not exist
368 * or if the /etc/hostid file is less than four bytes in size.
369 *
370 * 2. If the /etc/hostid file is at least 4 bytes, then return
371 * the first four bytes [0..3] in native endian order.
372 *
373 * 3. Always ignore bytes [4..] if they exist in the file.
374 *
375 * Only the first four bytes are significant, even on systems that
376 * have a 64-bit word size.
377 *
378 * See:
379 *
380 * eglibc: sysdeps/unix/sysv/linux/gethostid.c
381 * coreutils: src/hostid.c
382 *
383 * Notes:
384 *
385 * The /etc/hostid file on Solaris is a text file that often reads:
386 *
387 * # DO NOT EDIT
388 * "0123456789"
389 *
390 * Directly copying this file to Linux results in a constant
391 * hostid of 4f442023 because the default comment constitutes
392 * the first four bytes of the file.
393 *
394 */
395
396 static char *spl_hostid_path = HW_HOSTID_PATH;
397 module_param(spl_hostid_path, charp, 0444);
398 MODULE_PARM_DESC(spl_hostid_path, "The system hostid file (/etc/hostid)");
399
400 static int
hostid_read(uint32_t * hostid)401 hostid_read(uint32_t *hostid)
402 {
403 uint64_t size;
404 uint32_t value = 0;
405 int error;
406 loff_t off;
407 struct file *filp;
408 struct kstat stat;
409
410 filp = filp_open(spl_hostid_path, 0, 0);
411
412 if (IS_ERR(filp))
413 return (ENOENT);
414
415 error = spl_getattr(filp, &stat);
416 if (error) {
417 filp_close(filp, 0);
418 return (error);
419 }
420 size = stat.size;
421 // cppcheck-suppress sizeofwithnumericparameter
422 if (size < sizeof (HW_HOSTID_MASK)) {
423 filp_close(filp, 0);
424 return (EINVAL);
425 }
426
427 off = 0;
428 /*
429 * Read directly into the variable like eglibc does.
430 * Short reads are okay; native behavior is preserved.
431 */
432 error = kernel_read(filp, &value, sizeof (value), &off);
433 if (error < 0) {
434 filp_close(filp, 0);
435 return (EIO);
436 }
437
438 /* Mask down to 32 bits like coreutils does. */
439 *hostid = (value & HW_HOSTID_MASK);
440 filp_close(filp, 0);
441
442 return (0);
443 }
444
445 /*
446 * Return the system hostid. Preferentially use the spl_hostid module option
447 * when set, otherwise use the value in the /etc/hostid file.
448 */
449 uint32_t
zone_get_hostid(void * zone)450 zone_get_hostid(void *zone)
451 {
452 uint32_t hostid;
453
454 ASSERT0P(zone);
455
456 if (spl_hostid != 0)
457 return ((uint32_t)(spl_hostid & HW_HOSTID_MASK));
458
459 if (hostid_read(&hostid) == 0)
460 return (hostid);
461
462 return (0);
463 }
464 EXPORT_SYMBOL(zone_get_hostid);
465
466 static int
spl_kvmem_init(void)467 spl_kvmem_init(void)
468 {
469 int rc = 0;
470
471 rc = spl_kmem_init();
472 if (rc)
473 return (rc);
474
475 rc = spl_vmem_init();
476 if (rc) {
477 spl_kmem_fini();
478 return (rc);
479 }
480
481 return (rc);
482 }
483
484 /*
485 * We initialize the random number generator with 128 bits of entropy from the
486 * system random number generator. In the improbable case that we have a zero
487 * seed, we fallback to the system jiffies, unless it is also zero, in which
488 * situation we use a preprogrammed seed. We step forward by 2^64 iterations to
489 * initialize each of the per-cpu seeds so that the sequences generated on each
490 * CPU are guaranteed to never overlap in practice.
491 */
492 static int __init
spl_random_init(void)493 spl_random_init(void)
494 {
495 uint64_t s[4];
496 int i = 0;
497
498 spl_pseudo_entropy = __alloc_percpu(4 * sizeof (uint64_t),
499 sizeof (uint64_t));
500
501 if (!spl_pseudo_entropy)
502 return (-ENOMEM);
503
504 get_random_bytes(s, sizeof (s));
505
506 if (s[0] == 0 && s[1] == 0 && s[2] == 0 && s[3] == 0) {
507 if (jiffies != 0) {
508 s[0] = jiffies;
509 s[1] = ~0 - jiffies;
510 s[2] = ~jiffies;
511 s[3] = jiffies - ~0;
512 } else {
513 (void) memcpy(s, "improbable seed", 16);
514 }
515 printk("SPL: get_random_bytes() returned 0 "
516 "when generating random seed. Setting initial seed to "
517 "0x%016llx%016llx%016llx%016llx.\n", cpu_to_be64(s[0]),
518 cpu_to_be64(s[1]), cpu_to_be64(s[2]), cpu_to_be64(s[3]));
519 }
520
521 for_each_possible_cpu(i) {
522 uint64_t *wordp = per_cpu_ptr(spl_pseudo_entropy, i);
523
524 spl_rand_jump(s);
525
526 wordp[0] = s[0];
527 wordp[1] = s[1];
528 wordp[2] = s[2];
529 wordp[3] = s[3];
530 }
531
532 return (0);
533 }
534
535 static void
spl_random_fini(void)536 spl_random_fini(void)
537 {
538 free_percpu(spl_pseudo_entropy);
539 }
540
541 static void
spl_kvmem_fini(void)542 spl_kvmem_fini(void)
543 {
544 spl_vmem_fini();
545 spl_kmem_fini();
546 }
547
548 static int __init
spl_init(void)549 spl_init(void)
550 {
551 int rc = 0;
552
553 if ((rc = spl_random_init()))
554 goto out0;
555
556 if ((rc = spl_kvmem_init()))
557 goto out1;
558
559 if ((rc = spl_tsd_init()))
560 goto out2;
561
562 if ((rc = spl_proc_init()))
563 goto out3;
564
565 if ((rc = spl_kstat_init()))
566 goto out4;
567
568 if ((rc = spl_taskq_init()))
569 goto out5;
570
571 if ((rc = spl_kmem_cache_init()))
572 goto out6;
573
574 if ((rc = spl_zlib_init()))
575 goto out7;
576
577 if ((rc = spl_zone_init()))
578 goto out8;
579
580 return (rc);
581
582 out8:
583 spl_zlib_fini();
584 out7:
585 spl_kmem_cache_fini();
586 out6:
587 spl_taskq_fini();
588 out5:
589 spl_kstat_fini();
590 out4:
591 spl_proc_fini();
592 out3:
593 spl_tsd_fini();
594 out2:
595 spl_kvmem_fini();
596 out1:
597 spl_random_fini();
598 out0:
599 return (rc);
600 }
601
602 static void __exit
spl_fini(void)603 spl_fini(void)
604 {
605 spl_zone_fini();
606 spl_zlib_fini();
607 spl_kmem_cache_fini();
608 spl_taskq_fini();
609 spl_kstat_fini();
610 spl_proc_fini();
611 spl_tsd_fini();
612 spl_kvmem_fini();
613 spl_random_fini();
614 }
615
616 module_init(spl_init);
617 module_exit(spl_fini);
618
619 MODULE_DESCRIPTION("Solaris Porting Layer");
620 MODULE_AUTHOR(ZFS_META_AUTHOR);
621 MODULE_LICENSE("GPL");
622 MODULE_VERSION(ZFS_META_VERSION "-" ZFS_META_RELEASE);
623