xref: /freebsd/usr.sbin/cron/lib/misc.c (revision 089104e0e01f080c9cd45dc5f34c4f636dea4ca7)
1 /* Copyright 1988,1990,1993,1994 by Paul Vixie
2  * All rights reserved
3  *
4  * Distribute freely, except: don't remove my name from the source or
5  * documentation (don't take credit for my work), mark your changes (don't
6  * get me blamed for your possible bugs), don't alter or remove this
7  * notice.  May be sold if buildable source is provided to buyer.  No
8  * warrantee of any kind, express or implied, is included with this
9  * software; use at your own risk, responsibility for damages (if any) to
10  * anyone resulting from the use of this software rests entirely with the
11  * user.
12  *
13  * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
14  * I'll try to keep a version up to date.  I can be reached as follows:
15  * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
16  */
17 
18 #if !defined(lint) && !defined(LINT)
19 static const char rcsid[] =
20   "$FreeBSD$";
21 #endif
22 
23 /* vix 26jan87 [RCS has the rest of the log]
24  * vix 30dec86 [written]
25  */
26 
27 
28 #include "cron.h"
29 #if SYS_TIME_H
30 # include <sys/time.h>
31 #else
32 # include <time.h>
33 #endif
34 #include <sys/file.h>
35 #include <sys/stat.h>
36 #include <err.h>
37 #include <errno.h>
38 #include <string.h>
39 #include <fcntl.h>
40 #if defined(SYSLOG)
41 # include <syslog.h>
42 #endif
43 
44 
45 #if defined(LOG_DAEMON) && !defined(LOG_CRON)
46 #define LOG_CRON LOG_DAEMON
47 #endif
48 
49 
50 static int		LogFD = ERR;
51 
52 
53 int
54 strcmp_until(char *left, char *right, int until)
55 {
56 	register int	diff;
57 
58 	while (*left && *left != until && *left == *right) {
59 		left++;
60 		right++;
61 	}
62 
63 	if ((*left=='\0' || *left == until) &&
64 	    (*right=='\0' || *right == until)) {
65 		diff = 0;
66 	} else {
67 		diff = *left - *right;
68 	}
69 
70 	return diff;
71 }
72 
73 
74 /* strdtb(s) - delete trailing blanks in string 's' and return new length
75  */
76 int
77 strdtb(char *s)
78 {
79 	char	*x = s;
80 
81 	/* scan forward to the null
82 	 */
83 	while (*x)
84 		x++;
85 
86 	/* scan backward to either the first character before the string,
87 	 * or the last non-blank in the string, whichever comes first.
88 	 */
89 	do	{x--;}
90 	while (x >= s && isspace(*x));
91 
92 	/* one character beyond where we stopped above is where the null
93 	 * goes.
94 	 */
95 	*++x = '\0';
96 
97 	/* the difference between the position of the null character and
98 	 * the position of the first character of the string is the length.
99 	 */
100 	return x - s;
101 }
102 
103 
104 int
105 set_debug_flags(char *flags)
106 {
107 	/* debug flags are of the form    flag[,flag ...]
108 	 *
109 	 * if an error occurs, print a message to stdout and return FALSE.
110 	 * otherwise return TRUE after setting ERROR_FLAGS.
111 	 */
112 
113 #if !DEBUGGING
114 
115 	printf("this program was compiled without debugging enabled\n");
116 	return FALSE;
117 
118 #else /* DEBUGGING */
119 
120 	char	*pc = flags;
121 
122 	DebugFlags = 0;
123 
124 	while (*pc) {
125 		char	**test;
126 		int	mask;
127 
128 		/* try to find debug flag name in our list.
129 		 */
130 		for (	test = DebugFlagNames, mask = 1;
131 			*test && strcmp_until(*test, pc, ',');
132 			test++, mask <<= 1
133 		    )
134 			;
135 
136 		if (!*test) {
137 			fprintf(stderr,
138 				"unrecognized debug flag <%s> <%s>\n",
139 				flags, pc);
140 			return FALSE;
141 		}
142 
143 		DebugFlags |= mask;
144 
145 		/* skip to the next flag
146 		 */
147 		while (*pc && *pc != ',')
148 			pc++;
149 		if (*pc == ',')
150 			pc++;
151 	}
152 
153 	if (DebugFlags) {
154 		int	flag;
155 
156 		fprintf(stderr, "debug flags enabled:");
157 
158 		for (flag = 0;  DebugFlagNames[flag];  flag++)
159 			if (DebugFlags & (1 << flag))
160 				fprintf(stderr, " %s", DebugFlagNames[flag]);
161 		fprintf(stderr, "\n");
162 	}
163 
164 	return TRUE;
165 
166 #endif /* DEBUGGING */
167 }
168 
169 
170 void
171 set_cron_uid(void)
172 {
173 #if defined(BSD) || defined(POSIX)
174 	if (seteuid(ROOT_UID) < OK)
175 		err(ERROR_EXIT, "seteuid");
176 #else
177 	if (setuid(ROOT_UID) < OK)
178 		err(ERROR_EXIT, "setuid");
179 #endif
180 }
181 
182 
183 void
184 set_cron_cwd(void)
185 {
186 	struct stat	sb;
187 
188 	/* first check for CRONDIR ("/var/cron" or some such)
189 	 */
190 	if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
191 		warn("%s", CRONDIR);
192 		if (OK == mkdir(CRONDIR, 0700)) {
193 			warnx("%s: created", CRONDIR);
194 			stat(CRONDIR, &sb);
195 		} else {
196 			err(ERROR_EXIT, "%s: mkdir", CRONDIR);
197 		}
198 	}
199 	if (!(sb.st_mode & S_IFDIR))
200 		err(ERROR_EXIT, "'%s' is not a directory, bailing out", CRONDIR);
201 	if (chdir(CRONDIR) < OK)
202 		err(ERROR_EXIT, "cannot chdir(%s), bailing out", CRONDIR);
203 
204 	/* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
205 	 */
206 	if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
207 		warn("%s", SPOOL_DIR);
208 		if (OK == mkdir(SPOOL_DIR, 0700)) {
209 			warnx("%s: created", SPOOL_DIR);
210 			stat(SPOOL_DIR, &sb);
211 		} else {
212 			err(ERROR_EXIT, "%s: mkdir", SPOOL_DIR);
213 		}
214 	}
215 	if (!(sb.st_mode & S_IFDIR))
216 		err(ERROR_EXIT, "'%s' is not a directory, bailing out", SPOOL_DIR);
217 }
218 
219 
220 /* get_char(file) : like getc() but increment LineNumber on newlines
221  */
222 int
223 get_char(FILE *file)
224 {
225 	int	ch;
226 
227 	ch = getc(file);
228 	if (ch == '\n')
229 		Set_LineNum(LineNumber + 1)
230 	return ch;
231 }
232 
233 
234 /* unget_char(ch, file) : like ungetc but do LineNumber processing
235  */
236 void
237 unget_char(int ch, FILE *file)
238 {
239 	ungetc(ch, file);
240 	if (ch == '\n')
241 		Set_LineNum(LineNumber - 1)
242 }
243 
244 
245 /* get_string(str, max, file, termstr) : like fgets() but
246  *		(1) has terminator string which should include \n
247  *		(2) will always leave room for the null
248  *		(3) uses get_char() so LineNumber will be accurate
249  *		(4) returns EOF or terminating character, whichever
250  */
251 int
252 get_string(char *string, int size, FILE *file, char *terms)
253 {
254 	int	ch;
255 
256 	while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
257 		if (size > 1) {
258 			*string++ = (char) ch;
259 			size--;
260 		}
261 	}
262 
263 	if (size > 0)
264 		*string = '\0';
265 
266 	return ch;
267 }
268 
269 
270 /* skip_comments(file) : read past comment (if any)
271  */
272 void
273 skip_comments(FILE *file)
274 {
275 	int	ch;
276 
277 	while (EOF != (ch = get_char(file))) {
278 		/* ch is now the first character of a line.
279 		 */
280 
281 		while (ch == ' ' || ch == '\t')
282 			ch = get_char(file);
283 
284 		if (ch == EOF)
285 			break;
286 
287 		/* ch is now the first non-blank character of a line.
288 		 */
289 
290 		if (ch != '\n' && ch != '#')
291 			break;
292 
293 		/* ch must be a newline or comment as first non-blank
294 		 * character on a line.
295 		 */
296 
297 		while (ch != '\n' && ch != EOF)
298 			ch = get_char(file);
299 
300 		/* ch is now the newline of a line which we're going to
301 		 * ignore.
302 		 */
303 	}
304 	if (ch != EOF)
305 		unget_char(ch, file);
306 }
307 
308 
309 /* int in_file(char *string, FILE *file)
310  *	return TRUE if one of the lines in file matches string exactly,
311  *	FALSE otherwise.
312  */
313 static int
314 in_file(char *string, FILE *file)
315 {
316 	char line[MAX_TEMPSTR];
317 
318 	rewind(file);
319 	while (fgets(line, MAX_TEMPSTR, file)) {
320 		if (line[0] != '\0')
321 			if (line[strlen(line)-1] == '\n')
322 				line[strlen(line)-1] = '\0';
323 		if (0 == strcmp(line, string))
324 			return TRUE;
325 	}
326 	return FALSE;
327 }
328 
329 
330 /* int allowed(char *username)
331  *	returns TRUE if (ALLOW_FILE exists and user is listed)
332  *	or (DENY_FILE exists and user is NOT listed)
333  *	or (neither file exists but user=="root" so it's okay)
334  */
335 int
336 allowed(char *username)
337 {
338 	FILE	*allow, *deny;
339 	int	isallowed;
340 
341 	isallowed = FALSE;
342 
343 	deny = NULL;
344 #if defined(ALLOW_FILE) && defined(DENY_FILE)
345 	if ((allow = fopen(ALLOW_FILE, "r")) == NULL && errno != ENOENT)
346 		goto out;
347 	if ((deny = fopen(DENY_FILE, "r")) == NULL && errno != ENOENT)
348 		goto out;
349 	Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
350 #else
351 	allow = NULL;
352 #endif
353 
354 	if (allow)
355 		isallowed = in_file(username, allow);
356 	else if (deny)
357 		isallowed = !in_file(username, deny);
358 	else {
359 #if defined(ALLOW_ONLY_ROOT)
360 		isallowed = (strcmp(username, ROOT_USER) == 0);
361 #else
362 		isallowed = TRUE;
363 #endif
364 	}
365 out:	if (allow)
366 		fclose(allow);
367 	if (deny)
368 		fclose(deny);
369 	return (isallowed);
370 }
371 
372 
373 void
374 log_it(char *username, int xpid, char *event, const char *detail)
375 {
376 #if defined(LOG_FILE) || DEBUGGING
377 	PID_T			pid = xpid;
378 #endif
379 #if defined(LOG_FILE)
380 	char			*msg;
381 	TIME_T			now = time((TIME_T) 0);
382 	register struct tm	*t = localtime(&now);
383 #endif /*LOG_FILE*/
384 
385 #if defined(SYSLOG)
386 	static int		syslog_open = 0;
387 #endif
388 
389 #if defined(LOG_FILE)
390 	/* we assume that MAX_TEMPSTR will hold the date, time, &punctuation.
391 	 */
392 	msg = malloc(strlen(username)
393 		     + strlen(event)
394 		     + strlen(detail)
395 		     + MAX_TEMPSTR);
396 
397 	if (msg == NULL)
398 		warnx("failed to allocate memory for log message");
399 	else {
400 		if (LogFD < OK) {
401 			LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
402 			if (LogFD < OK) {
403 				warn("can't open log file %s", LOG_FILE);
404 			} else {
405 				(void) fcntl(LogFD, F_SETFD, 1);
406 			}
407 		}
408 
409 		/* we have to sprintf() it because fprintf() doesn't always
410 		 * write everything out in one chunk and this has to be
411 		 * atomically appended to the log file.
412 		 */
413 		sprintf(msg, "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n",
414 			username,
415 			t->tm_mon+1, t->tm_mday, t->tm_hour, t->tm_min,
416 			t->tm_sec, pid, event, detail);
417 
418 		/* we have to run strlen() because sprintf() returns (char*)
419 		 * on old BSD.
420 		 */
421 		if (LogFD < OK || write(LogFD, msg, strlen(msg)) < OK) {
422 			if (LogFD >= OK)
423 				warn("%s", LOG_FILE);
424 			warnx("can't write to log file");
425 			write(STDERR, msg, strlen(msg));
426 		}
427 
428 		free(msg);
429 	}
430 #endif /*LOG_FILE*/
431 
432 #if defined(SYSLOG)
433 	if (!syslog_open) {
434 		/* we don't use LOG_PID since the pid passed to us by
435 		 * our client may not be our own.  therefore we want to
436 		 * print the pid ourselves.
437 		 */
438 # ifdef LOG_DAEMON
439 		openlog(ProgramName, LOG_PID, LOG_CRON);
440 # else
441 		openlog(ProgramName, LOG_PID);
442 # endif
443 		syslog_open = TRUE;		/* assume openlog success */
444 	}
445 
446 	syslog(LOG_INFO, "(%s) %s (%s)\n", username, event, detail);
447 
448 #endif /*SYSLOG*/
449 
450 #if DEBUGGING
451 	if (DebugFlags) {
452 		fprintf(stderr, "log_it: (%s %d) %s (%s)\n",
453 			username, pid, event, detail);
454 	}
455 #endif
456 }
457 
458 
459 void
460 log_close(void)
461 {
462 	if (LogFD != ERR) {
463 		close(LogFD);
464 		LogFD = ERR;
465 	}
466 }
467 
468 
469 /* two warnings:
470  *	(1) this routine is fairly slow
471  *	(2) it returns a pointer to static storage
472  */
473 char *
474 first_word(char *s, char *t)
475 {
476 	static char retbuf[2][MAX_TEMPSTR + 1];	/* sure wish C had GC */
477 	static int retsel = 0;
478 	register char *rb, *rp;
479 
480 	/* select a return buffer */
481 	retsel = 1-retsel;
482 	rb = &retbuf[retsel][0];
483 	rp = rb;
484 
485 	/* skip any leading terminators */
486 	while (*s && (NULL != strchr(t, *s))) {
487 		s++;
488 	}
489 
490 	/* copy until next terminator or full buffer */
491 	while (*s && (NULL == strchr(t, *s)) && (rp < &rb[MAX_TEMPSTR])) {
492 		*rp++ = *s++;
493 	}
494 
495 	/* finish the return-string and return it */
496 	*rp = '\0';
497 	return rb;
498 }
499 
500 
501 /* warning:
502  *	heavily ascii-dependent.
503  */
504 static void
505 mkprint(register char *dst, register unsigned char *src, register int len)
506 {
507 	while (len-- > 0)
508 	{
509 		register unsigned char ch = *src++;
510 
511 		if (ch < ' ') {			/* control character */
512 			*dst++ = '^';
513 			*dst++ = ch + '@';
514 		} else if (ch < 0177) {		/* printable */
515 			*dst++ = ch;
516 		} else if (ch == 0177) {	/* delete/rubout */
517 			*dst++ = '^';
518 			*dst++ = '?';
519 		} else {			/* parity character */
520 			sprintf(dst, "\\%03o", ch);
521 			dst += 4;
522 		}
523 	}
524 	*dst = '\0';
525 }
526 
527 
528 /* warning:
529  *	returns a pointer to malloc'd storage, you must call free yourself.
530  */
531 char *
532 mkprints(unsigned char *src, unsigned int len)
533 {
534 	register char *dst = malloc(len*4 + 1);
535 
536 	if (dst != NULL)
537 		mkprint(dst, src, len);
538 
539 	return dst;
540 }
541 
542 
543 #ifdef MAIL_DATE
544 /* Sat, 27 Feb 93 11:44:51 CST
545  * 123456789012345678901234567
546  */
547 char *
548 arpadate(time_t *clock)
549 {
550 	time_t t = clock ?*clock :time(0L);
551 	struct tm *tm = localtime(&t);
552 	static char ret[32];	/* zone name might be >3 chars */
553 
554 	if (tm->tm_year >= 100)
555 		tm->tm_year += 1900;
556 
557 	(void) snprintf(ret, sizeof(ret), "%s, %2d %s %d %02d:%02d:%02d %s",
558 		       DowNames[tm->tm_wday],
559 		       tm->tm_mday,
560 		       MonthNames[tm->tm_mon],
561 		       tm->tm_year,
562 		       tm->tm_hour,
563 		       tm->tm_min,
564 		       tm->tm_sec,
565 		       TZONE(*tm));
566 	return ret;
567 }
568 #endif /*MAIL_DATE*/
569 
570 
571 #ifdef HAVE_SAVED_UIDS
572 static int save_euid;
573 int swap_uids(void) { save_euid = geteuid(); return seteuid(getuid()); }
574 int swap_uids_back(void) { return seteuid(save_euid); }
575 #else /*HAVE_SAVED_UIDS*/
576 int swap_uids(void) { return setreuid(geteuid(), getuid()); }
577 int swap_uids_back(void) { return swap_uids(); }
578 #endif /*HAVE_SAVED_UIDS*/
579