1 /* $NetBSD: misc.c,v 1.5 2017/08/17 08:53:00 christos Exp $ */
2
3 /* Copyright 1988,1990,1993,1994 by Paul Vixie
4 * All rights reserved
5 */
6
7 /*
8 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
9 * Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
10 *
11 * Permission to use, copy, modify, and distribute this software for any
12 * purpose with or without fee is hereby granted, provided that the above
13 * copyright notice and this permission notice appear in all copies.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
16 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
18 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
21 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22 */
23 #include <sys/cdefs.h>
24 #if !defined(lint) && !defined(LINT)
25 #if 0
26 static char rcsid[] = "Id: misc.c,v 1.16 2004/01/23 18:56:43 vixie Exp";
27 #else
28 __RCSID("$NetBSD: misc.c,v 1.5 2017/08/17 08:53:00 christos Exp $");
29 #endif
30 #endif
31
32 /* vix 26jan87 [RCS has the rest of the log]
33 * vix 30dec86 [written]
34 */
35
36 #include "cron.h"
37 #include <limits.h>
38 #include <vis.h>
39
40 #if defined(SYSLOG) && defined(LOG_FILE)
41 # undef LOG_FILE
42 #endif
43
44 #if defined(LOG_DAEMON) && !defined(LOG_CRON)
45 # define LOG_CRON LOG_DAEMON
46 #endif
47
48 #ifndef FACILITY
49 #define FACILITY LOG_CRON
50 #endif
51
52 static int LogFD = ERR;
53
54 #if defined(SYSLOG)
55 static int syslog_open = FALSE;
56 #endif
57
58 static void mkprint(char *, char *, size_t);
59
60 /*
61 * glue_strings is the overflow-safe equivalent of
62 * sprintf(buffer, "%s%c%s", a, separator, b);
63 *
64 * returns 1 on success, 0 on failure. 'buffer' MUST NOT be used if
65 * glue_strings fails.
66 */
67 int
glue_strings(char * buffer,size_t buffer_size,const char * a,const char * b,char separator)68 glue_strings(char *buffer, size_t buffer_size, const char *a, const char *b,
69 char separator)
70 {
71 char *buf;
72 char *buf_end;
73
74 if (buffer_size == 0)
75 return (0);
76 buf_end = buffer + buffer_size;
77 buf = buffer;
78
79 for ( /* nothing */; buf < buf_end && *a != '\0'; buf++, a++ )
80 *buf = *a;
81 if (buf == buf_end)
82 return (0);
83 if (separator != '/' || buf == buffer || buf[-1] != '/')
84 *buf++ = separator;
85 if (buf == buf_end)
86 return (0);
87 for ( /* nothing */; buf < buf_end && *b != '\0'; buf++, b++ )
88 *buf = *b;
89 if (buf == buf_end)
90 return (0);
91 *buf = '\0';
92 return (1);
93 }
94
95 int
strcmp_until(const char * left,const char * right,char until)96 strcmp_until(const char *left, const char *right, char until) {
97 while (*left && *left != until && *left == *right) {
98 left++;
99 right++;
100 }
101
102 if ((*left=='\0' || *left == until) &&
103 (*right=='\0' || *right == until)) {
104 return (0);
105 }
106 return (*left - *right);
107 }
108
109 #ifdef notdef
110 /* strdtb(s) - delete trailing blanks in string 's' and return new length
111 */
112 int
strdtb(char * s)113 strdtb(char *s) {
114 char *x = s;
115
116 /* scan forward to the null
117 */
118 while (*x)
119 x++;
120
121 /* scan backward to either the first character before the string,
122 * or the last non-blank in the string, whichever comes first.
123 */
124 do {x--;}
125 while (x >= s && isspace((unsigned char)*x));
126
127 /* one character beyond where we stopped above is where the null
128 * goes.
129 */
130 *++x = '\0';
131
132 /* the difference between the position of the null character and
133 * the position of the first character of the string is the length.
134 */
135 return (int)(x - s);
136 }
137 #endif
138
139 int
set_debug_flags(const char * flags)140 set_debug_flags(const char *flags) {
141 /* debug flags are of the form flag[,flag ...]
142 *
143 * if an error occurs, print a message to stdout and return FALSE.
144 * otherwise return TRUE after setting ERROR_FLAGS.
145 */
146
147 #if !DEBUGGING
148
149 printf("this program was compiled without debugging enabled\n");
150 return (FALSE);
151
152 #else /* DEBUGGING */
153
154 const char *pc = flags;
155
156 DebugFlags = 0;
157
158 while (*pc) {
159 const char * const *test;
160 int mask;
161
162 /* try to find debug flag name in our list.
163 */
164 for (test = DebugFlagNames, mask = 1;
165 *test != NULL && strcmp_until(*test, pc, ',');
166 test++, mask <<= 1)
167 continue;
168
169 if (!*test) {
170 warnx("unrecognized debug flag <%s> <%s>\n", flags, pc);
171 return (FALSE);
172 }
173
174 DebugFlags |= mask;
175
176 /* skip to the next flag
177 */
178 while (*pc && *pc != ',')
179 pc++;
180 if (*pc == ',')
181 pc++;
182 }
183
184 if (DebugFlags) {
185 int flag;
186
187 (void)fprintf(stderr, "debug flags enabled:");
188
189 for (flag = 0; DebugFlagNames[flag]; flag++)
190 if (DebugFlags & (1 << flag))
191 (void)fprintf(stderr, " %s", DebugFlagNames[flag]);
192 (void)fprintf(stderr, "\n");
193 }
194
195 return (TRUE);
196
197 #endif /* DEBUGGING */
198 }
199
200 void
set_cron_uid(void)201 set_cron_uid(void) {
202 #if defined(BSD) || defined(POSIX)
203 if (seteuid(ROOT_UID) < OK) {
204 err(ERROR_EXIT, "cannot seteuid");
205 }
206 #else
207 if (setuid(ROOT_UID) < OK) {
208 err(ERROR_EXIT, "cannot setuid");
209 }
210 #endif
211 }
212
213 void
set_cron_cwd(void)214 set_cron_cwd(void) {
215 struct stat sb;
216 struct group *grp = NULL;
217
218 #ifdef CRON_GROUP
219 grp = getgrnam(CRON_GROUP);
220 #endif
221 /* first check for CRONDIR ("/var/cron" or some such)
222 */
223 #ifdef ENABLE_FIX_DIRECTORIES
224 if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
225 warn("Cannot stat `%s'", CRONDIR);
226 if (OK == mkdir(CRONDIR, 0710)) {
227 (void)fprintf(stderr, "%s: created\n", CRONDIR);
228 if (stat(CRONDIR, &sb) == -1)
229 err(ERROR_EXIT, "cannot stat `%s'", CRONDIR);
230 } else {
231 err(ERROR_EXIT, "cannot create `%s'", CRONDIR);
232 }
233 }
234 if (!S_ISDIR(sb.st_mode)) {
235 errx(ERROR_EXIT, "`%s' is not a directory, bailing out.",
236 CRONDIR);
237 }
238 #endif /* ENABLE_FIX_DIRECTORIES */
239 if (chdir(CRONDIR) < OK) {
240 err(ERROR_EXIT, "cannot chdir `%s', bailing out.\n", CRONDIR);
241 }
242
243 /* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
244 */
245 #ifdef ENABLE_FIX_DIRECTORIES
246 if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
247 warn("cannot stat `%s'", SPOOL_DIR);
248 if (OK == mkdir(SPOOL_DIR, 0700)) {
249 (void)fprintf(stderr, "%s: created\n", SPOOL_DIR);
250 if (stat(SPOOL_DIR, &sb) == -1)
251 err(ERROR_EXIT, "cannot stat `%s'", CRONDIR);
252 } else {
253 err(ERROR_EXIT, "cannot create `%s'", SPOOL_DIR);
254 }
255 }
256 #else
257 if (stat(SPOOL_DIR, &sb)) {
258 err(ERROR_EXIT, "cannot stat `%s'", SPOOL_DIR);
259 }
260 #endif /* ENABLE_FIX_DIRECTORIES */
261 if (!S_ISDIR(sb.st_mode)) {
262 errx(ERROR_EXIT, "`%s' is not a directory, bailing out.",
263 SPOOL_DIR);
264 }
265 if (grp != NULL) {
266 if (sb.st_gid != grp->gr_gid) {
267 #ifdef ENABLE_FIX_DIRECTORIES
268 errx(ERROR_EXIT, "Bad group %d != %d for `%s'",
269 (int)sb.st_gid, (int)grp->gr_gid, SPOOL_DIR);
270 #else
271 if (chown(SPOOL_DIR, (uid_t)-1, grp->gr_gid) == -1)
272 err(ERROR_EXIT, "cannot chown `%s'", SPOOL_DIR);
273 #endif
274 }
275 if (sb.st_mode != 01730)
276 #ifdef ENABLE_FIX_DIRECTORIES
277 errx(ERROR_EXIT, "Bad mode %#o != %#o for `%s'",
278 (int)sb.st_mode, 01730, SPOOL_DIR);
279 #else
280 if (chmod(SPOOL_DIR, 01730) == -1)
281 err(ERROR_EXIT, "cannot chmod `%s'", SPOOL_DIR);
282 #endif
283 }
284 }
285
286 /* acquire_daemonlock() - write our PID into /etc/cron.pid, unless
287 * another daemon is already running, which we detect here.
288 *
289 * note: main() calls us twice; once before forking, once after.
290 * we maintain static storage of the file pointer so that we
291 * can rewrite our PID into _PATH_CRON_PID after the fork.
292 */
293 void
acquire_daemonlock(int closeflag)294 acquire_daemonlock(int closeflag) {
295 static int fd = -1;
296 char buf[3*MAX_FNAME];
297 const char *pidfile;
298 char *ep;
299 long otherpid;
300 ssize_t num;
301
302 if (closeflag) {
303 /* close stashed fd for child so we don't leak it. */
304 if (fd != -1) {
305 (void)close(fd);
306 fd = -1;
307 }
308 return;
309 }
310
311 if (fd == -1) {
312 pidfile = _PATH_CRON_PID;
313 /* Initial mode is 0600 to prevent flock() race/DoS. */
314 if ((fd = open(pidfile, O_RDWR|O_CREAT, 0600)) == -1) {
315 log_itx("CRON", getpid(), "DEATH",
316 "can't open or create %s: %s",
317 pidfile, strerror(errno));
318 exit(ERROR_EXIT);
319 }
320 /* fd must be > STDERR since we dup fd 0-2 to /dev/null */
321 if (fd <= STDERR) {
322 if (dup2(fd, STDERR + 1) < 0) {
323 log_itx("CRON", getpid(), "DEATH",
324 "can't dup pid fd: %s", strerror(errno));
325 exit(ERROR_EXIT);
326 }
327 close(fd);
328 fd = STDERR + 1;
329 }
330
331 if (flock(fd, LOCK_EX|LOCK_NB) < OK) {
332 int save_errno = errno;
333
334 memset(buf, 0, sizeof(buf));
335 if ((num = read(fd, buf, sizeof(buf) - 1)) > 0 &&
336 (otherpid = strtol(buf, &ep, 10)) > 0 &&
337 ep != buf && *ep == '\n' && otherpid != LONG_MAX) {
338 log_itx("CRON", getpid(), "DEATH",
339 "can't lock %s, otherpid may be %ld: %s",
340 pidfile, otherpid, strerror(save_errno));
341 } else {
342 log_itx("CRON", getpid(), "DEATH",
343 "can't lock %s, otherpid unknown: %s",
344 pidfile, strerror(save_errno));
345 }
346 exit(ERROR_EXIT);
347 }
348 (void) fchmod(fd, 0644);
349 (void) fcntl(fd, F_SETFD, 1);
350 }
351
352 (void)snprintf(buf, sizeof(buf), "%ld\n", (long)getpid());
353 (void) lseek(fd, (off_t)0, SEEK_SET);
354 num = write(fd, buf, strlen(buf));
355 (void) ftruncate(fd, num);
356
357 /* abandon fd even though the file is open. we need to keep
358 * it open and locked, but we don't need the handles elsewhere.
359 */
360 }
361
362 /* get_char(file) : like getc() but increment LineNumber on newlines
363 */
364 int
get_char(FILE * file)365 get_char(FILE *file) {
366 int ch;
367
368 ch = getc(file);
369 if (ch == '\n')
370 Set_LineNum(LineNumber + 1);
371 return (ch);
372 }
373
374 /* unget_char(ch, file) : like ungetc but do LineNumber processing
375 */
376 void
unget_char(int ch,FILE * file)377 unget_char(int ch, FILE *file) {
378 (void)ungetc(ch, file);
379 if (ch == '\n')
380 Set_LineNum(LineNumber - 1);
381 }
382
383 /* get_string(str, max, file, termstr) : like fgets() but
384 * (1) has terminator string which should include \n
385 * (2) will always leave room for the null
386 * (3) uses get_char() so LineNumber will be accurate
387 * (4) returns EOF or terminating character, whichever
388 */
389 int
get_string(char * string,int size,FILE * file,const char * terms)390 get_string(char *string, int size, FILE *file, const char *terms) {
391 int ch;
392
393 while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
394 if (size > 1) {
395 *string++ = (char) ch;
396 size--;
397 }
398 }
399
400 if (size > 0)
401 *string = '\0';
402
403 return (ch);
404 }
405
406 /* skip_comments(file) : read past comment (if any)
407 */
408 void
skip_comments(FILE * file)409 skip_comments(FILE *file) {
410 int ch;
411
412 while (EOF != (ch = get_char(file))) {
413 /* ch is now the first character of a line.
414 */
415
416 while (ch == ' ' || ch == '\t')
417 ch = get_char(file);
418
419 if (ch == EOF)
420 break;
421
422 /* ch is now the first non-blank character of a line.
423 */
424
425 if (ch != '\n' && ch != '#')
426 break;
427
428 /* ch must be a newline or comment as first non-blank
429 * character on a line.
430 */
431
432 while (ch != '\n' && ch != EOF)
433 ch = get_char(file);
434
435 /* ch is now the newline of a line which we're going to
436 * ignore.
437 */
438 }
439 if (ch != EOF)
440 unget_char(ch, file);
441 }
442
443 void
log_itx(const char * username,PID_T xpid,const char * event,const char * fmt,...)444 log_itx(const char *username, PID_T xpid, const char *event, const char *fmt,
445 ...)
446 {
447 char *detail;
448 va_list ap;
449 va_start(ap, fmt);
450 if (vasprintf(&detail, fmt, ap) == -1) {
451 va_end(ap);
452 return;
453 }
454 log_it(username, xpid, event, detail);
455 free(detail);
456 }
457
458 void
log_it(const char * username,PID_T xpid,const char * event,const char * detail)459 log_it(const char *username, PID_T xpid, const char *event, const char *detail) {
460 #if defined(LOG_FILE) || DEBUGGING
461 PID_T pid = xpid;
462 #endif
463 #if defined(LOG_FILE)
464 char *msg;
465 int msglen;
466 TIME_T now = time((TIME_T) 0);
467 struct tm *t = localtime(&now);
468
469 if (LogFD < OK) {
470 LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
471 if (LogFD < OK) {
472 warn("can't open log file `%s'", LOG_FILE);
473 } else {
474 (void) fcntl(LogFD, F_SETFD, FD_CLOEXEC);
475 }
476 }
477
478 /* we have to sprintf() it because fprintf() doesn't always write
479 * everything out in one chunk and this has to be atomically appended
480 * to the log file.
481 */
482 msglen = asprintf(&msg,
483 "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n", username,
484 t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, pid,
485 event, detail);
486 if (msglen == -1)
487 return;
488
489 if (LogFD < OK || write(LogFD, msg, (size_t)msglen) < OK) {
490 warn("can't write to log file");
491 write(STDERR, msg, (size_t)msglen);
492 }
493
494 free(msg);
495 #endif /*LOG_FILE*/
496
497 #if defined(SYSLOG)
498 if (!syslog_open) {
499 # ifdef LOG_DAEMON
500 openlog(getprogname(), LOG_PID, FACILITY);
501 # else
502 openlog(getprogname(), LOG_PID);
503 # endif
504 syslog_open = TRUE; /* assume openlog success */
505 }
506
507 syslog(LOG_INFO, "(%s) %s (%s)", username, event, detail);
508
509 #endif /*SYSLOG*/
510
511 #if DEBUGGING
512 if (DebugFlags) {
513 (void)fprintf(stderr, "log_it: (%s %ld) %s (%s)\n",
514 username, (long)pid, event, detail);
515 }
516 #endif
517 }
518
519 void
log_close(void)520 log_close(void) {
521 if (LogFD != ERR) {
522 (void)close(LogFD);
523 LogFD = ERR;
524 }
525 #if defined(SYSLOG)
526 closelog();
527 syslog_open = FALSE;
528 #endif /*SYSLOG*/
529 }
530
531 /* warning:
532 * heavily ascii-dependent.
533 */
534 static void
mkprint(char * dst,char * src,size_t len)535 mkprint(char *dst, char *src, size_t len)
536 {
537 while(len > 0 && isblank((unsigned char) *src))
538 len--, src++;
539
540 (void)strvisx(dst, src, len, VIS_TAB|VIS_NL);
541 }
542
543 /* warning:
544 * returns a pointer to malloc'd storage, you must call free yourself.
545 */
546 char *
mkprints(char * src,size_t len)547 mkprints(char *src, size_t len)
548 {
549 char *dst = malloc(len*4 + 1);
550
551 if (dst)
552 mkprint(dst, src, len);
553
554 return (dst);
555 }
556
557 #ifdef MAIL_DATE
558 /* Sat, 27 Feb 1993 11:44:51 -0800 (CST)
559 * 1234567890123456789012345678901234567
560 */
561 char *
arpadate(time_t * clock)562 arpadate(time_t *clock)
563 {
564 time_t t = clock ? *clock : time((TIME_T) 0);
565 struct tm tm = *localtime(&t);
566 long gmtoff = get_gmtoff(&t, &tm);
567 int hours = gmtoff / SECONDS_PER_HOUR;
568 int minutes = (gmtoff - (hours * SECONDS_PER_HOUR)) / SECONDS_PER_MINUTE;
569 static char ret[64]; /* zone name might be >3 chars */
570
571 if (minutes < 0)
572 minutes = -minutes;
573
574 (void)strftime(ret, sizeof(ret), "%a, %e %b %Y %T ????? (%Z)", &tm);
575 (void)snprintf(strchr(ret, '?'), "% .2d%.2d", hours, minutes);
576 ret[sizeof(ret) - 1] = '\0';
577 return ret;
578 }
579 #endif /*MAIL_DATE*/
580
581 size_t
strlens(const char * last,...)582 strlens(const char *last, ...) {
583 va_list ap;
584 size_t ret = 0;
585 const char *str;
586
587 va_start(ap, last);
588 for (str = last; str != NULL; str = va_arg(ap, const char *))
589 ret += strlen(str);
590 va_end(ap);
591 return (ret);
592 }
593
594 /* Return the offset from GMT in seconds (algorithm taken from sendmail).
595 *
596 * warning:
597 * clobbers the static storage space used by localtime() and gmtime().
598 * If the local pointer is non-NULL it *must* point to a local copy.
599 */
600 #ifndef HAVE_TM_GMTOFF
get_gmtoff(time_t * clock,struct tm * local)601 long get_gmtoff(time_t *clock, struct tm *local)
602 {
603 struct tm gmt;
604 long offset;
605
606 gmt = *gmtime(clock);
607 if (local == NULL)
608 local = localtime(clock);
609
610 offset = (local->tm_sec - gmt.tm_sec) +
611 ((local->tm_min - gmt.tm_min) * 60) +
612 ((local->tm_hour - gmt.tm_hour) * 3600);
613
614 /* Timezone may cause year rollover to happen on a different day. */
615 if (local->tm_year < gmt.tm_year)
616 offset -= 24 * 3600;
617 else if (local->tm_year > gmt.tm_year)
618 offset -= 24 * 3600;
619 else if (local->tm_yday < gmt.tm_yday)
620 offset -= 24 * 3600;
621 else if (local->tm_yday > gmt.tm_yday)
622 offset += 24 * 3600;
623
624 return (offset);
625 }
626 #endif /* HAVE_TM_GMTOFF */
627