misc.c revision 320229 
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)
19static const char rcsid[] =
20  "$FreeBSD: stable/10/usr.sbin/cron/lib/misc.c 320229 2017-06-22 07:54:12Z ngie $";
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
50static int		LogFD = ERR;
51
52
53int
54strcmp_until(left, right, until)
55	char	*left;
56	char	*right;
57	int	until;
58{
59	register int	diff;
60
61	while (*left && *left != until && *left == *right) {
62		left++;
63		right++;
64	}
65
66	if ((*left=='\0' || *left == until) &&
67	    (*right=='\0' || *right == until)) {
68		diff = 0;
69	} else {
70		diff = *left - *right;
71	}
72
73	return diff;
74}
75
76
77/* strdtb(s) - delete trailing blanks in string 's' and return new length
78 */
79int
80strdtb(s)
81	char	*s;
82{
83	char	*x = s;
84
85	/* scan forward to the null
86	 */
87	while (*x)
88		x++;
89
90	/* scan backward to either the first character before the string,
91	 * or the last non-blank in the string, whichever comes first.
92	 */
93	do	{x--;}
94	while (x >= s && isspace(*x));
95
96	/* one character beyond where we stopped above is where the null
97	 * goes.
98	 */
99	*++x = '\0';
100
101	/* the difference between the position of the null character and
102	 * the position of the first character of the string is the length.
103	 */
104	return x - s;
105}
106
107
108int
109set_debug_flags(flags)
110	char	*flags;
111{
112	/* debug flags are of the form    flag[,flag ...]
113	 *
114	 * if an error occurs, print a message to stdout and return FALSE.
115	 * otherwise return TRUE after setting ERROR_FLAGS.
116	 */
117
118#if !DEBUGGING
119
120	printf("this program was compiled without debugging enabled\n");
121	return FALSE;
122
123#else /* DEBUGGING */
124
125	char	*pc = flags;
126
127	DebugFlags = 0;
128
129	while (*pc) {
130		char	**test;
131		int	mask;
132
133		/* try to find debug flag name in our list.
134		 */
135		for (	test = DebugFlagNames, mask = 1;
136			*test && strcmp_until(*test, pc, ',');
137			test++, mask <<= 1
138		    )
139			;
140
141		if (!*test) {
142			fprintf(stderr,
143				"unrecognized debug flag <%s> <%s>\n",
144				flags, pc);
145			return FALSE;
146		}
147
148		DebugFlags |= mask;
149
150		/* skip to the next flag
151		 */
152		while (*pc && *pc != ',')
153			pc++;
154		if (*pc == ',')
155			pc++;
156	}
157
158	if (DebugFlags) {
159		int	flag;
160
161		fprintf(stderr, "debug flags enabled:");
162
163		for (flag = 0;  DebugFlagNames[flag];  flag++)
164			if (DebugFlags & (1 << flag))
165				fprintf(stderr, " %s", DebugFlagNames[flag]);
166		fprintf(stderr, "\n");
167	}
168
169	return TRUE;
170
171#endif /* DEBUGGING */
172}
173
174
175void
176set_cron_uid()
177{
178#if defined(BSD) || defined(POSIX)
179	if (seteuid(ROOT_UID) < OK)
180		err(ERROR_EXIT, "seteuid");
181#else
182	if (setuid(ROOT_UID) < OK)
183		err(ERROR_EXIT, "setuid");
184#endif
185}
186
187
188void
189set_cron_cwd()
190{
191	struct stat	sb;
192
193	/* first check for CRONDIR ("/var/cron" or some such)
194	 */
195	if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
196		warn("%s", CRONDIR);
197		if (OK == mkdir(CRONDIR, 0700)) {
198			warnx("%s: created", CRONDIR);
199			stat(CRONDIR, &sb);
200		} else {
201			err(ERROR_EXIT, "%s: mkdir", CRONDIR);
202		}
203	}
204	if (!(sb.st_mode & S_IFDIR))
205		err(ERROR_EXIT, "'%s' is not a directory, bailing out", CRONDIR);
206	if (chdir(CRONDIR) < OK)
207		err(ERROR_EXIT, "cannot chdir(%s), bailing out", CRONDIR);
208
209	/* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
210	 */
211	if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
212		warn("%s", SPOOL_DIR);
213		if (OK == mkdir(SPOOL_DIR, 0700)) {
214			warnx("%s: created", SPOOL_DIR);
215			stat(SPOOL_DIR, &sb);
216		} else {
217			err(ERROR_EXIT, "%s: mkdir", SPOOL_DIR);
218		}
219	}
220	if (!(sb.st_mode & S_IFDIR))
221		err(ERROR_EXIT, "'%s' is not a directory, bailing out", SPOOL_DIR);
222}
223
224
225/* get_char(file) : like getc() but increment LineNumber on newlines
226 */
227int
228get_char(file)
229	FILE	*file;
230{
231	int	ch;
232
233	ch = getc(file);
234	if (ch == '\n')
235		Set_LineNum(LineNumber + 1)
236	return ch;
237}
238
239
240/* unget_char(ch, file) : like ungetc but do LineNumber processing
241 */
242void
243unget_char(ch, file)
244	int	ch;
245	FILE	*file;
246{
247	ungetc(ch, file);
248	if (ch == '\n')
249		Set_LineNum(LineNumber - 1)
250}
251
252
253/* get_string(str, max, file, termstr) : like fgets() but
254 *		(1) has terminator string which should include \n
255 *		(2) will always leave room for the null
256 *		(3) uses get_char() so LineNumber will be accurate
257 *		(4) returns EOF or terminating character, whichever
258 */
259int
260get_string(string, size, file, terms)
261	char	*string;
262	int	size;
263	FILE	*file;
264	char	*terms;
265{
266	int	ch;
267
268	while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
269		if (size > 1) {
270			*string++ = (char) ch;
271			size--;
272		}
273	}
274
275	if (size > 0)
276		*string = '\0';
277
278	return ch;
279}
280
281
282/* skip_comments(file) : read past comment (if any)
283 */
284void
285skip_comments(file)
286	FILE	*file;
287{
288	int	ch;
289
290	while (EOF != (ch = get_char(file))) {
291		/* ch is now the first character of a line.
292		 */
293
294		while (ch == ' ' || ch == '\t')
295			ch = get_char(file);
296
297		if (ch == EOF)
298			break;
299
300		/* ch is now the first non-blank character of a line.
301		 */
302
303		if (ch != '\n' && ch != '#')
304			break;
305
306		/* ch must be a newline or comment as first non-blank
307		 * character on a line.
308		 */
309
310		while (ch != '\n' && ch != EOF)
311			ch = get_char(file);
312
313		/* ch is now the newline of a line which we're going to
314		 * ignore.
315		 */
316	}
317	if (ch != EOF)
318		unget_char(ch, file);
319}
320
321
322/* int in_file(char *string, FILE *file)
323 *	return TRUE if one of the lines in file matches string exactly,
324 *	FALSE otherwise.
325 */
326static int
327in_file(char *string, FILE *file)
328{
329	char line[MAX_TEMPSTR];
330
331	rewind(file);
332	while (fgets(line, MAX_TEMPSTR, file)) {
333		if (line[0] != '\0')
334			if (line[strlen(line)-1] == '\n')
335				line[strlen(line)-1] = '\0';
336		if (0 == strcmp(line, string))
337			return TRUE;
338	}
339	return FALSE;
340}
341
342
343/* int allowed(char *username)
344 *	returns TRUE if (ALLOW_FILE exists and user is listed)
345 *	or (DENY_FILE exists and user is NOT listed)
346 *	or (neither file exists but user=="root" so it's okay)
347 */
348int
349allowed(username)
350	char *username;
351{
352	FILE	*allow, *deny;
353	int	isallowed;
354
355	isallowed = FALSE;
356
357	deny = NULL;
358#if defined(ALLOW_FILE) && defined(DENY_FILE)
359	if ((allow = fopen(ALLOW_FILE, "r")) == NULL && errno != ENOENT)
360		goto out;
361	if ((deny = fopen(DENY_FILE, "r")) == NULL && errno != ENOENT)
362		goto out;
363	Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
364#else
365	allow = NULL;
366#endif
367
368	if (allow)
369		isallowed = in_file(username, allow);
370	else if (deny)
371		isallowed = !in_file(username, deny);
372	else {
373#if defined(ALLOW_ONLY_ROOT)
374		isallowed = (strcmp(username, ROOT_USER) == 0);
375#else
376		isallowed = TRUE;
377#endif
378	}
379out:	if (allow)
380		fclose(allow);
381	if (deny)
382		fclose(deny);
383	return (isallowed);
384}
385
386
387void
388log_it(username, xpid, event, detail)
389	char	*username;
390	int	xpid;
391	char	*event;
392	char	*detail;
393{
394#if defined(LOG_FILE) || DEBUGGING
395	PID_T			pid = xpid;
396#endif
397#if defined(LOG_FILE)
398	char			*msg;
399	TIME_T			now = time((TIME_T) 0);
400	register struct tm	*t = localtime(&now);
401#endif /*LOG_FILE*/
402
403#if defined(SYSLOG)
404	static int		syslog_open = 0;
405#endif
406
407#if defined(LOG_FILE)
408	/* we assume that MAX_TEMPSTR will hold the date, time, &punctuation.
409	 */
410	msg = malloc(strlen(username)
411		     + strlen(event)
412		     + strlen(detail)
413		     + MAX_TEMPSTR);
414
415	if (msg == NULL)
416		warnx("failed to allocate memory for log message");
417	else {
418		if (LogFD < OK) {
419			LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
420			if (LogFD < OK) {
421				warn("can't open log file %s", LOG_FILE);
422			} else {
423				(void) fcntl(LogFD, F_SETFD, 1);
424			}
425		}
426
427		/* we have to sprintf() it because fprintf() doesn't always
428		 * write everything out in one chunk and this has to be
429		 * atomically appended to the log file.
430		 */
431		sprintf(msg, "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n",
432			username,
433			t->tm_mon+1, t->tm_mday, t->tm_hour, t->tm_min,
434			t->tm_sec, pid, event, detail);
435
436		/* we have to run strlen() because sprintf() returns (char*)
437		 * on old BSD.
438		 */
439		if (LogFD < OK || write(LogFD, msg, strlen(msg)) < OK) {
440			if (LogFD >= OK)
441				warn("%s", LOG_FILE);
442			warnx("can't write to log file");
443			write(STDERR, msg, strlen(msg));
444		}
445
446		free(msg);
447	}
448#endif /*LOG_FILE*/
449
450#if defined(SYSLOG)
451	if (!syslog_open) {
452		/* we don't use LOG_PID since the pid passed to us by
453		 * our client may not be our own.  therefore we want to
454		 * print the pid ourselves.
455		 */
456# ifdef LOG_DAEMON
457		openlog(ProgramName, LOG_PID, LOG_CRON);
458# else
459		openlog(ProgramName, LOG_PID);
460# endif
461		syslog_open = TRUE;		/* assume openlog success */
462	}
463
464	syslog(LOG_INFO, "(%s) %s (%s)\n", username, event, detail);
465
466#endif /*SYSLOG*/
467
468#if DEBUGGING
469	if (DebugFlags) {
470		fprintf(stderr, "log_it: (%s %d) %s (%s)\n",
471			username, pid, event, detail);
472	}
473#endif
474}
475
476
477void
478log_close() {
479	if (LogFD != ERR) {
480		close(LogFD);
481		LogFD = ERR;
482	}
483}
484
485
486/* two warnings:
487 *	(1) this routine is fairly slow
488 *	(2) it returns a pointer to static storage
489 */
490char *
491first_word(s, t)
492	register char *s;	/* string we want the first word of */
493	register char *t;	/* terminators, implicitly including \0 */
494{
495	static char retbuf[2][MAX_TEMPSTR + 1];	/* sure wish C had GC */
496	static int retsel = 0;
497	register char *rb, *rp;
498
499	/* select a return buffer */
500	retsel = 1-retsel;
501	rb = &retbuf[retsel][0];
502	rp = rb;
503
504	/* skip any leading terminators */
505	while (*s && (NULL != strchr(t, *s))) {
506		s++;
507	}
508
509	/* copy until next terminator or full buffer */
510	while (*s && (NULL == strchr(t, *s)) && (rp < &rb[MAX_TEMPSTR])) {
511		*rp++ = *s++;
512	}
513
514	/* finish the return-string and return it */
515	*rp = '\0';
516	return rb;
517}
518
519
520/* warning:
521 *	heavily ascii-dependent.
522 */
523static void
524mkprint(register char *dst, register unsigned char *src, register int len)
525{
526	while (len-- > 0)
527	{
528		register unsigned char ch = *src++;
529
530		if (ch < ' ') {			/* control character */
531			*dst++ = '^';
532			*dst++ = ch + '@';
533		} else if (ch < 0177) {		/* printable */
534			*dst++ = ch;
535		} else if (ch == 0177) {	/* delete/rubout */
536			*dst++ = '^';
537			*dst++ = '?';
538		} else {			/* parity character */
539			sprintf(dst, "\\%03o", ch);
540			dst += 4;
541		}
542	}
543	*dst = '\0';
544}
545
546
547/* warning:
548 *	returns a pointer to malloc'd storage, you must call free yourself.
549 */
550char *
551mkprints(src, len)
552	register unsigned char *src;
553	register unsigned int len;
554{
555	register char *dst = malloc(len*4 + 1);
556
557	if (dst != NULL)
558		mkprint(dst, src, len);
559
560	return dst;
561}
562
563
564#ifdef MAIL_DATE
565/* Sat, 27 Feb 93 11:44:51 CST
566 * 123456789012345678901234567
567 */
568char *
569arpadate(clock)
570	time_t *clock;
571{
572	time_t t = clock ?*clock :time(0L);
573	struct tm *tm = localtime(&t);
574	static char ret[32];	/* zone name might be >3 chars */
575
576	if (tm->tm_year >= 100)
577		tm->tm_year += 1900;
578
579	(void) snprintf(ret, sizeof(ret), "%s, %2d %s %d %02d:%02d:%02d %s",
580		       DowNames[tm->tm_wday],
581		       tm->tm_mday,
582		       MonthNames[tm->tm_mon],
583		       tm->tm_year,
584		       tm->tm_hour,
585		       tm->tm_min,
586		       tm->tm_sec,
587		       TZONE(*tm));
588	return ret;
589}
590#endif /*MAIL_DATE*/
591
592
593#ifdef HAVE_SAVED_UIDS
594static int save_euid;
595int swap_uids() { save_euid = geteuid(); return seteuid(getuid()); }
596int swap_uids_back() { return seteuid(save_euid); }
597#else /*HAVE_SAVED_UIDS*/
598int swap_uids() { return setreuid(geteuid(), getuid()); }
599int swap_uids_back() { return swap_uids(); }
600#endif /*HAVE_SAVED_UIDS*/
601