1 /*-
2 * Copyright (c) 2016-2017 Nuxi, https://nuxi.nl/
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 #include <sys/param.h>
30 #include <sys/resource.h>
31 #include <sys/socket.h>
32 #include <sys/sysctl.h>
33
34 #include <assert.h>
35 #include <ctype.h>
36 #include <err.h>
37 #include <errno.h>
38 #include <math.h>
39 #include <regex.h>
40 #include <stdbool.h>
41 #include <stdint.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <zlib.h>
47
48 /* Regular expressions for filtering output. */
49 static regex_t inc_regex;
50 static regex_t exc_regex;
51
52 /*
53 * Cursor for iterating over all of the system's sysctl OIDs.
54 */
55 struct oid {
56 int id[CTL_MAXNAME];
57 size_t len;
58 };
59
60 /* Initializes the cursor to point to start of the tree. */
61 static void
oid_get_root(struct oid * o)62 oid_get_root(struct oid *o)
63 {
64
65 o->id[0] = 1;
66 o->len = 1;
67 }
68
69 /* Obtains the OID for a sysctl by name. */
70 static void
oid_get_by_name(struct oid * o,const char * name)71 oid_get_by_name(struct oid *o, const char *name)
72 {
73
74 o->len = nitems(o->id);
75 if (sysctlnametomib(name, o->id, &o->len) != 0)
76 err(1, "sysctl(%s)", name);
77 }
78
79 /* Returns whether an OID is placed below another OID. */
80 static bool
oid_is_beneath(struct oid * oa,struct oid * ob)81 oid_is_beneath(struct oid *oa, struct oid *ob)
82 {
83
84 return (oa->len >= ob->len &&
85 memcmp(oa->id, ob->id, ob->len * sizeof(oa->id[0])) == 0);
86 }
87
88 /* Advances the cursor to the next OID. */
89 static bool
oid_get_next(const struct oid * cur,struct oid * next)90 oid_get_next(const struct oid *cur, struct oid *next)
91 {
92 int lookup[CTL_MAXNAME + 2];
93 size_t nextsize;
94
95 lookup[0] = 0;
96 lookup[1] = 2;
97 memcpy(lookup + 2, cur->id, cur->len * sizeof(lookup[0]));
98 nextsize = sizeof(next->id);
99 if (sysctl(lookup, 2 + cur->len, &next->id, &nextsize, 0, 0) != 0) {
100 if (errno == ENOENT)
101 return (false);
102 err(1, "sysctl(next)");
103 }
104 next->len = nextsize / sizeof(next->id[0]);
105 return (true);
106 }
107
108 /*
109 * OID formatting metadata.
110 */
111 struct oidformat {
112 unsigned int kind;
113 char format[BUFSIZ];
114 };
115
116 /* Returns whether the OID represents a temperature value. */
117 static bool
oidformat_is_temperature(const struct oidformat * of)118 oidformat_is_temperature(const struct oidformat *of)
119 {
120
121 return (of->format[0] == 'I' && of->format[1] == 'K');
122 }
123
124 /* Returns whether the OID represents a timeval structure. */
125 static bool
oidformat_is_timeval(const struct oidformat * of)126 oidformat_is_timeval(const struct oidformat *of)
127 {
128
129 return (strcmp(of->format, "S,timeval") == 0);
130 }
131
132 /* Fetches the formatting metadata for an OID. */
133 static bool
oid_get_format(const struct oid * o,struct oidformat * of)134 oid_get_format(const struct oid *o, struct oidformat *of)
135 {
136 int lookup[CTL_MAXNAME + 2];
137 size_t oflen;
138
139 lookup[0] = 0;
140 lookup[1] = 4;
141 memcpy(lookup + 2, o->id, o->len * sizeof(lookup[0]));
142 oflen = sizeof(*of);
143 if (sysctl(lookup, 2 + o->len, of, &oflen, 0, 0) != 0) {
144 if (errno == ENOENT)
145 return (false);
146 err(1, "sysctl(oidfmt)");
147 }
148 return (true);
149 }
150
151 /*
152 * Container for holding the value of an OID.
153 */
154 struct oidvalue {
155 enum { SIGNED, UNSIGNED, FLOAT } type;
156 union {
157 intmax_t s;
158 uintmax_t u;
159 double f;
160 } value;
161 };
162
163 /* Extracts the value of an OID, converting it to a floating-point number. */
164 static double
oidvalue_get_float(const struct oidvalue * ov)165 oidvalue_get_float(const struct oidvalue *ov)
166 {
167
168 switch (ov->type) {
169 case SIGNED:
170 return (ov->value.s);
171 case UNSIGNED:
172 return (ov->value.u);
173 case FLOAT:
174 return (ov->value.f);
175 default:
176 assert(0 && "Unknown value type");
177 }
178 }
179
180 /* Sets the value of an OID as a signed integer. */
181 static void
oidvalue_set_signed(struct oidvalue * ov,intmax_t s)182 oidvalue_set_signed(struct oidvalue *ov, intmax_t s)
183 {
184
185 ov->type = SIGNED;
186 ov->value.s = s;
187 }
188
189 /* Sets the value of an OID as an unsigned integer. */
190 static void
oidvalue_set_unsigned(struct oidvalue * ov,uintmax_t u)191 oidvalue_set_unsigned(struct oidvalue *ov, uintmax_t u)
192 {
193
194 ov->type = UNSIGNED;
195 ov->value.u = u;
196 }
197
198 /* Sets the value of an OID as a floating-point number. */
199 static void
oidvalue_set_float(struct oidvalue * ov,double f)200 oidvalue_set_float(struct oidvalue *ov, double f)
201 {
202
203 ov->type = FLOAT;
204 ov->value.f = f;
205 }
206
207 /* Prints the value of an OID to a file stream. */
208 static void
oidvalue_print(const struct oidvalue * ov,FILE * fp)209 oidvalue_print(const struct oidvalue *ov, FILE *fp)
210 {
211
212 switch (ov->type) {
213 case SIGNED:
214 fprintf(fp, "%jd", ov->value.s);
215 break;
216 case UNSIGNED:
217 fprintf(fp, "%ju", ov->value.u);
218 break;
219 case FLOAT:
220 switch (fpclassify(ov->value.f)) {
221 case FP_INFINITE:
222 if (signbit(ov->value.f))
223 fprintf(fp, "-Inf");
224 else
225 fprintf(fp, "+Inf");
226 break;
227 case FP_NAN:
228 fprintf(fp, "Nan");
229 break;
230 default:
231 fprintf(fp, "%.6f", ov->value.f);
232 break;
233 }
234 break;
235 }
236 }
237
238 /* Fetches the value of an OID. */
239 static bool
oid_get_value(const struct oid * o,const struct oidformat * of,struct oidvalue * ov)240 oid_get_value(const struct oid *o, const struct oidformat *of,
241 struct oidvalue *ov)
242 {
243
244 switch (of->kind & CTLTYPE) {
245 #define GET_VALUE(ctltype, type) \
246 case (ctltype): { \
247 type value; \
248 size_t valuesize; \
249 \
250 valuesize = sizeof(value); \
251 if (sysctl(o->id, o->len, &value, &valuesize, 0, 0) != 0) \
252 return (false); \
253 if ((type)-1 > 0) \
254 oidvalue_set_unsigned(ov, value); \
255 else \
256 oidvalue_set_signed(ov, value); \
257 break; \
258 }
259 GET_VALUE(CTLTYPE_INT, int);
260 GET_VALUE(CTLTYPE_UINT, unsigned int);
261 GET_VALUE(CTLTYPE_LONG, long);
262 GET_VALUE(CTLTYPE_ULONG, unsigned long);
263 GET_VALUE(CTLTYPE_S8, int8_t);
264 GET_VALUE(CTLTYPE_U8, uint8_t);
265 GET_VALUE(CTLTYPE_S16, int16_t);
266 GET_VALUE(CTLTYPE_U16, uint16_t);
267 GET_VALUE(CTLTYPE_S32, int32_t);
268 GET_VALUE(CTLTYPE_U32, uint32_t);
269 GET_VALUE(CTLTYPE_S64, int64_t);
270 GET_VALUE(CTLTYPE_U64, uint64_t);
271 #undef GET_VALUE
272 case CTLTYPE_OPAQUE:
273 if (oidformat_is_timeval(of)) {
274 struct timeval tv;
275 size_t tvsize;
276
277 tvsize = sizeof(tv);
278 if (sysctl(o->id, o->len, &tv, &tvsize, 0, 0) != 0)
279 return (false);
280 oidvalue_set_float(ov,
281 (double)tv.tv_sec + (double)tv.tv_usec / 1000000);
282 return (true);
283 } else if (strcmp(of->format, "S,loadavg") == 0) {
284 struct loadavg la;
285 size_t lasize;
286
287 /*
288 * Only return the one minute load average, as
289 * the others can be inferred using avg_over_time().
290 */
291 lasize = sizeof(la);
292 if (sysctl(o->id, o->len, &la, &lasize, 0, 0) != 0)
293 return (false);
294 oidvalue_set_float(ov,
295 (double)la.ldavg[0] / (double)la.fscale);
296 return (true);
297 }
298 return (false);
299 default:
300 return (false);
301 }
302
303 /* Convert temperatures from decikelvin to degrees Celsius. */
304 if (oidformat_is_temperature(of)) {
305 double v;
306 int e;
307
308 v = oidvalue_get_float(ov);
309 if (v < 0) {
310 oidvalue_set_float(ov, NAN);
311 } else {
312 e = of->format[2] >= '0' && of->format[2] <= '9' ?
313 of->format[2] - '0' : 1;
314 oidvalue_set_float(ov, v / pow(10, e) - 273.15);
315 }
316 }
317 return (true);
318 }
319
320 /*
321 * The full name of an OID, stored as a series of components.
322 */
323 struct oidname {
324 struct oid oid;
325 char names[BUFSIZ];
326 char labels[BUFSIZ];
327 };
328
329 /*
330 * Initializes the OID name object with an empty value.
331 */
332 static void
oidname_init(struct oidname * on)333 oidname_init(struct oidname *on)
334 {
335
336 on->oid.len = 0;
337 }
338
339 /* Fetches the name and labels of an OID, reusing the previous results. */
340 static void
oid_get_name(const struct oid * o,struct oidname * on)341 oid_get_name(const struct oid *o, struct oidname *on)
342 {
343 int lookup[CTL_MAXNAME + 2];
344 char *c, *label;
345 size_t i, len;
346
347 /* Fetch the name and split it up in separate components. */
348 lookup[0] = 0;
349 lookup[1] = 1;
350 memcpy(lookup + 2, o->id, o->len * sizeof(lookup[0]));
351 len = sizeof(on->names);
352 if (sysctl(lookup, 2 + o->len, on->names, &len, 0, 0) != 0)
353 err(1, "sysctl(name)");
354 for (c = strchr(on->names, '.'); c != NULL; c = strchr(c + 1, '.'))
355 *c = '\0';
356
357 /* No need to fetch labels for components that we already have. */
358 label = on->labels;
359 for (i = 0; i < o->len && i < on->oid.len && o->id[i] == on->oid.id[i];
360 ++i)
361 label += strlen(label) + 1;
362
363 /* Fetch the remaining labels. */
364 lookup[1] = 6;
365 for (; i < o->len; ++i) {
366 len = on->labels + sizeof(on->labels) - label;
367 if (sysctl(lookup, 2 + i + 1, label, &len, 0, 0) == 0) {
368 label += len;
369 } else if (errno == ENOENT) {
370 *label++ = '\0';
371 } else {
372 err(1, "sysctl(oidlabel)");
373 }
374 }
375 on->oid = *o;
376 }
377
378 /* Populates the name and labels of an OID to a buffer. */
379 static void
oid_get_metric(const struct oidname * on,const struct oidformat * of,char * metric,size_t mlen)380 oid_get_metric(const struct oidname *on, const struct oidformat *of,
381 char *metric, size_t mlen)
382 {
383 const char *name, *label;
384 size_t i;
385 char separator, buf[BUFSIZ];
386
387 /* Print the name of the metric. */
388 snprintf(metric, mlen, "%s", "sysctl");
389 name = on->names;
390 label = on->labels;
391 for (i = 0; i < on->oid.len; ++i) {
392 if (*label == '\0') {
393 strlcat(metric, "_", mlen);
394 while (*name != '\0') {
395 /* Map unsupported characters to underscores. */
396 snprintf(buf, sizeof(buf), "%c",
397 isalnum(*name) ? *name : '_');
398 strlcat(metric, buf, mlen);
399 ++name;
400 }
401 }
402 name += strlen(name) + 1;
403 label += strlen(label) + 1;
404 }
405 if (oidformat_is_temperature(of))
406 strlcat(metric, "_celsius", mlen);
407 else if (oidformat_is_timeval(of))
408 strlcat(metric, "_seconds", mlen);
409
410 /* Print the labels of the metric. */
411 name = on->names;
412 label = on->labels;
413 separator = '{';
414 for (i = 0; i < on->oid.len; ++i) {
415 if (*label != '\0') {
416 assert(label[strspn(label,
417 "abcdefghijklmnopqrstuvwxyz"
418 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
419 "0123456789_")] == '\0');
420 snprintf(buf, sizeof(buf), "%c%s=\"", separator, label);
421 strlcat(metric, buf, mlen);
422 while (*name != '\0') {
423 /* Escape backslashes and double quotes. */
424 if (*name == '\\' || *name == '"')
425 strlcat(metric, "\\", mlen);
426 snprintf(buf, sizeof(buf), "%c", *name++);
427 strlcat(metric, buf, mlen);
428 }
429 strlcat(metric, "\"", mlen);
430 separator = ',';
431 }
432 name += strlen(name) + 1;
433 label += strlen(label) + 1;
434 }
435 if (separator != '{')
436 strlcat(metric, "}", mlen);
437 }
438
439 /* Returns whether the OID name has any labels associated to it. */
440 static bool
oidname_has_labels(const struct oidname * on)441 oidname_has_labels(const struct oidname *on)
442 {
443 size_t i;
444
445 for (i = 0; i < on->oid.len; ++i)
446 if (on->labels[i] != 0)
447 return (true);
448 return (false);
449 }
450
451 /*
452 * The description of an OID.
453 */
454 struct oiddescription {
455 char description[BUFSIZ];
456 };
457
458 /*
459 * Fetches the description of an OID.
460 */
461 static bool
oid_get_description(const struct oid * o,struct oiddescription * od)462 oid_get_description(const struct oid *o, struct oiddescription *od)
463 {
464 int lookup[CTL_MAXNAME + 2];
465 char *newline;
466 size_t odlen;
467
468 lookup[0] = 0;
469 lookup[1] = 5;
470 memcpy(lookup + 2, o->id, o->len * sizeof(lookup[0]));
471 odlen = sizeof(od->description);
472 if (sysctl(lookup, 2 + o->len, &od->description, &odlen, 0, 0) != 0) {
473 if (errno == ENOENT)
474 return (false);
475 err(1, "sysctl(oiddescr)");
476 }
477
478 newline = strchr(od->description, '\n');
479 if (newline != NULL)
480 *newline = '\0';
481
482 return (*od->description != '\0');
483 }
484
485 /* Prints the description of an OID to a file stream. */
486 static void
oiddescription_print(const struct oiddescription * od,FILE * fp)487 oiddescription_print(const struct oiddescription *od, FILE *fp)
488 {
489
490 fprintf(fp, "%s", od->description);
491 }
492
493 static void
oid_print(const struct oid * o,struct oidname * on,bool print_description,bool exclude,bool include,FILE * fp)494 oid_print(const struct oid *o, struct oidname *on, bool print_description,
495 bool exclude, bool include, FILE *fp)
496 {
497 struct oidformat of;
498 struct oidvalue ov;
499 struct oiddescription od;
500 char metric[BUFSIZ];
501
502 if (!oid_get_format(o, &of) || !oid_get_value(o, &of, &ov))
503 return;
504 oid_get_name(o, on);
505
506 oid_get_metric(on, &of, metric, sizeof(metric));
507
508 if (exclude && regexec(&exc_regex, metric, 0, NULL, 0) == 0)
509 return;
510
511 if (include && regexec(&inc_regex, metric, 0, NULL, 0) != 0)
512 return;
513
514 /*
515 * Print the line with the description. Prometheus expects a
516 * single unique description for every metric, which cannot be
517 * guaranteed by sysctl if labels are present. Omit the
518 * description if labels are present.
519 */
520 if (print_description && !oidname_has_labels(on) &&
521 oid_get_description(o, &od)) {
522 fprintf(fp, "# HELP ");
523 fprintf(fp, "%s", metric);
524 fputc(' ', fp);
525 oiddescription_print(&od, fp);
526 fputc('\n', fp);
527 }
528
529 /* Print the line with the value. */
530 fprintf(fp, "%s", metric);
531 fputc(' ', fp);
532 oidvalue_print(&ov, fp);
533 fputc('\n', fp);
534 }
535
536 /* Gzip compresses a buffer of memory. */
537 static bool
buf_gzip(const char * in,size_t inlen,char * out,size_t * outlen)538 buf_gzip(const char *in, size_t inlen, char *out, size_t *outlen)
539 {
540 z_stream stream = {
541 .next_in = __DECONST(unsigned char *, in),
542 .avail_in = inlen,
543 .next_out = (unsigned char *)out,
544 .avail_out = *outlen,
545 };
546
547 if (deflateInit2(&stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
548 MAX_WBITS + 16, 8, Z_DEFAULT_STRATEGY) != Z_OK ||
549 deflate(&stream, Z_FINISH) != Z_STREAM_END) {
550 return (false);
551 }
552 *outlen = stream.total_out;
553 return (deflateEnd(&stream) == Z_OK);
554 }
555
556 static void
usage(void)557 usage(void)
558 {
559
560 fprintf(stderr, "%s",
561 "usage: prometheus_sysctl_exporter [-dgh] [-e pattern] [-i pattern]\n"
562 "\t[prefix ...]\n");
563 exit(1);
564 }
565
566 int
main(int argc,char * argv[])567 main(int argc, char *argv[])
568 {
569 struct oidname on;
570 char *http_buf;
571 FILE *fp;
572 size_t http_buflen;
573 int ch, error;
574 bool exclude, include, gzip_mode, http_mode, print_descriptions;
575 char errbuf[BUFSIZ];
576
577 /* Parse command line flags. */
578 include = exclude = gzip_mode = http_mode = print_descriptions = false;
579 while ((ch = getopt(argc, argv, "de:ghi:")) != -1) {
580 switch (ch) {
581 case 'd':
582 print_descriptions = true;
583 break;
584 case 'e':
585 error = regcomp(&exc_regex, optarg, REG_EXTENDED);
586 if (error != 0) {
587 regerror(error, &exc_regex, errbuf, sizeof(errbuf));
588 errx(1, "bad regular expression '%s': %s",
589 optarg, errbuf);
590 }
591 exclude = true;
592 break;
593 case 'g':
594 gzip_mode = true;
595 break;
596 case 'h':
597 http_mode = true;
598 break;
599 case 'i':
600 error = regcomp(&inc_regex, optarg, REG_EXTENDED);
601 if (error != 0) {
602 regerror(error, &inc_regex, errbuf, sizeof(errbuf));
603 errx(1, "bad regular expression '%s': %s",
604 optarg, errbuf);
605 }
606 include = true;
607 break;
608 default:
609 usage();
610 }
611 }
612 argc -= optind;
613 argv += optind;
614
615 /* HTTP output: cache metrics in buffer. */
616 if (http_mode) {
617 fp = open_memstream(&http_buf, &http_buflen);
618 if (fp == NULL)
619 err(1, "open_memstream");
620 } else {
621 fp = stdout;
622 }
623
624 oidname_init(&on);
625 if (argc == 0) {
626 struct oid o;
627
628 /* Print all OIDs. */
629 oid_get_root(&o);
630 do {
631 oid_print(&o, &on, print_descriptions, exclude, include, fp);
632 } while (oid_get_next(&o, &o));
633 } else {
634 int i;
635
636 /* Print only trees provided as arguments. */
637 for (i = 0; i < argc; ++i) {
638 struct oid o, root;
639
640 oid_get_by_name(&root, argv[i]);
641 o = root;
642 do {
643 oid_print(&o, &on, print_descriptions, exclude, include, fp);
644 } while (oid_get_next(&o, &o) &&
645 oid_is_beneath(&o, &root));
646 }
647 }
648
649 if (http_mode) {
650 const char *content_encoding = "";
651
652 if (ferror(fp) || fclose(fp) != 0)
653 err(1, "Cannot generate output");
654
655 /* Gzip compress the output. */
656 if (gzip_mode) {
657 char *buf;
658 size_t buflen;
659
660 buflen = http_buflen;
661 buf = malloc(buflen);
662 if (buf == NULL)
663 err(1, "Cannot allocate compression buffer");
664 if (buf_gzip(http_buf, http_buflen, buf, &buflen)) {
665 content_encoding = "Content-Encoding: gzip\r\n";
666 free(http_buf);
667 http_buf = buf;
668 http_buflen = buflen;
669 } else {
670 free(buf);
671 }
672 }
673
674 /* Print HTTP header and metrics. */
675 dprintf(STDOUT_FILENO,
676 "HTTP/1.1 200 OK\r\n"
677 "Connection: close\r\n"
678 "%s"
679 "Content-Length: %zu\r\n"
680 "Content-Type: text/plain; version=0.0.4\r\n"
681 "\r\n",
682 content_encoding, http_buflen);
683 write(STDOUT_FILENO, http_buf, http_buflen);
684 free(http_buf);
685
686 /* Drain output. */
687 if (shutdown(STDIN_FILENO, SHUT_WR) == 0) {
688 char buf[1024];
689
690 while (read(STDIN_FILENO, buf, sizeof(buf)) > 0) {
691 }
692 }
693 }
694 return (0);
695 }
696