usr.sbin/cron/misc.c

   1 /*      $NetBSD: misc.c,v 1.13 2006/05/21 19:26:43 christos Exp $       */
   2
   3 /* Copyright 1988,1990,1993,1994 by Paul Vixie
   4  * All rights reserved
   5  *
   6  * Distribute freely, except: don't remove my name from the source or
   7  * documentation (don't take credit for my work), mark your changes (don't
   8  * get me blamed for your possible bugs), don't alter or remove this
   9  * notice.  May be sold if buildable source is provided to buyer.  No
  10  * warrantee of any kind, express or implied, is included with this
  11  * software; use at your own risk, responsibility for damages (if any) to
  12  * anyone resulting from the use of this software rests entirely with the
  13  * user.
  14  *
  15  * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
  16  * I'll try to keep a version up to date.  I can be reached as follows:
  17  * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
  18  */
  19
  20 #include <sys/cdefs.h>
  21 #if !defined(lint) && !defined(LINT)
  22 #if 0
  23 static char rcsid[] = "Id: misc.c,v 2.9 1994/01/15 20:43:43 vixie Exp";
  24 #else
  25 __RCSID("$NetBSD: misc.c,v 1.13 2006/05/21 19:26:43 christos Exp $");
  26 #endif
  27 #endif
  28
  29 /* vix 26jan87 [RCS has the rest of the log]
  30  * vix 30dec86 [written]
  31  */
  32
  33
  34 #include "cron.h"
  35 #if SYS_TIME_H
  36 # include <sys/time.h>
  37 #else
  38 # include <time.h>
  39 #endif
  40 #include <sys/file.h>
  41 #include <sys/stat.h>
  42 #include <err.h>
  43 #include <errno.h>
  44 #include <string.h>
  45 #include <fcntl.h>
  46 #if defined(SYSLOG)
  47 # include <syslog.h>
  48 #endif
  49 #include <ctype.h>
  50 #include <vis.h>
  51
  52 #if defined(LOG_DAEMON) && !defined(LOG_CRON)
  53 #define LOG_CRON LOG_DAEMON
  54 #endif
  55
  56 static int in_file(char *, FILE *);
  57 static void mkprint(char *, unsigned char *, int);
  58
  59 static int              LogFD = ERR;
  60
  61
  62 int
  63 strcmp_until(const char *left, const char *right, int until)
  64 {
  65         int     diff;
  66
  67         while (*left && *left != until && *left == *right) {
  68                 left++;
  69                 right++;
  70         }
  71
  72         if ((*left=='\0' || *left == until) &&
  73             (*right=='\0' || *right == until)) {
  74                 diff = 0;
  75         } else {
  76                 diff = *left - *right;
  77         }
  78
  79         return diff;
  80 }
  81
  82
  83 /* strdtb(s) - delete trailing blanks in string 's' and return new length
  84  */
  85 int
  86 strdtb(char *s)
  87 {
  88         char    *x = s;
  89
  90         /* scan forward to the null
  91          */
  92         while (*x)
  93                 x++;
  94
  95         /* scan backward to either the first character before the string,
  96          * or the last non-blank in the string, whichever comes first.
  97          */
  98         do      {x--;}
  99         while (x >= s && isspace((unsigned char)*x));
 100
 101         /* one character beyond where we stopped above is where the null
 102          * goes.
 103          */
 104         *++x = '\0';
 105
 106         /* the difference between the position of the null character and
 107          * the position of the first character of the string is the length.
 108          */
 109         return x - s;
 110 }
 111
 112
 113 int
 114 set_debug_flags(char *flags)
 115 {
 116         /* debug flags are of the form    flag[,flag ...]
 117          *
 118          * if an error occurs, print a message to stdout and return FALSE.
 119          * otherwise return TRUE after setting ERROR_FLAGS.
 120          */
 121
 122 #if !DEBUGGING
 123
 124         printf("this program was compiled without debugging enabled\n");
 125         return FALSE;
 126
 127 #else /* DEBUGGING */
 128
 129         char    *pc = flags;
 130
 131         DebugFlags = 0;
 132
 133         while (*pc) {
 134                 const char      * const *test;
 135                 int     mask;
 136
 137                 /* try to find debug flag name in our list.
 138                  */
 139                 for (   test = DebugFlagNames, mask = 1;
 140                         *test && strcmp_until(*test, pc, ',');
 141                         test++, mask <<= 1
 142                     )
 143                         ;
 144
 145                 if (!*test) {
 146                         fprintf(stderr,
 147                                 "unrecognized debug flag <%s> <%s>\n",
 148                                 flags, pc);
 149                         return FALSE;
 150                 }
 151
 152                 DebugFlags |= mask;
 153
 154                 /* skip to the next flag
 155                  */
 156                 while (*pc && *pc != ',')
 157                         pc++;
 158                 if (*pc == ',')
 159                         pc++;
 160         }
 161
 162         if (DebugFlags) {
 163                 int     flag;
 164
 165                 fprintf(stderr, "debug flags enabled:");
 166
 167                 for (flag = 0;  DebugFlagNames[flag];  flag++)
 168                         if (DebugFlags & (1 << flag))
 169                                 fprintf(stderr, " %s", DebugFlagNames[flag]);
 170                 fprintf(stderr, "\n");
 171         }
 172
 173         return TRUE;
 174
 175 #endif /* DEBUGGING */
 176 }
 177
 178
 179 void
 180 set_cron_uid(void)
 181 {
 182 #if defined(BSD) || defined(POSIX)
 183         if (seteuid(ROOT_UID) < OK) {
 184                 warn("cannot seteuid");
 185                 exit(ERROR_EXIT);
 186         }
 187 #else
 188         if (setuid(ROOT_UID) < OK) {
 189                 warn("cannot setuid");
 190                 exit(ERROR_EXIT);
 191         }
 192 #endif
 193 }
 194
 195
 196 void
 197 set_cron_cwd(void)
 198 {
 199         struct stat     sb;
 200
 201         /* first check for CRONDIR ("/var/cron" or some such)
 202          */
 203         if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
 204                 warn("cannot stat %s", CRONDIR);
 205                 if (OK == mkdir(CRONDIR, 0700)) {
 206                         fprintf(stderr, "%s: created\n", CRONDIR);
 207                         stat(CRONDIR, &sb);
 208                 } else {
 209                         warn("cannot create %s", CRONDIR);
 210                         exit(ERROR_EXIT);
 211                 }
 212         }
 213         if (!S_ISDIR(sb.st_mode)) {
 214                 warnx("`%s' is not a directory, bailing out", CRONDIR);
 215                 exit(ERROR_EXIT);
 216         }
 217         if (chdir(CRONDIR) < OK) {
 218                 warn("cannot chdir(%s), bailing out", CRONDIR);
 219                 exit(ERROR_EXIT);
 220         }
 221
 222         /* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
 223          */
 224         if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
 225                 warn("cannot stat %s", SPOOL_DIR);
 226                 if (OK == mkdir(SPOOL_DIR, 0700)) {
 227                         fprintf(stderr, "%s: created\n", SPOOL_DIR);
 228                         stat(SPOOL_DIR, &sb);
 229                 } else {
 230                         warn("cannot create %s", SPOOL_DIR);
 231                         exit(ERROR_EXIT);
 232                 }
 233         }
 234         if (!S_ISDIR(sb.st_mode)) {
 235                 fprintf(stderr, "'%s' is not a directory, bailing out.\n",
 236                         SPOOL_DIR);
 237                 exit(ERROR_EXIT);
 238         }
 239 }
 240
 241
 242 /* acquire_daemonlock() - write our PID into /etc/cron.pid, unless
 243  *      another daemon is already running, which we detect here.
 244  *
 245  * note: main() calls us twice; once before forking, once after.
 246  *      we maintain static storage of the file pointer so that we
 247  *      can rewrite our PID into the PIDFILE after the fork.
 248  *
 249  * it would be great if fflush() disassociated the file buffer.
 250  */
 251 void
 252 acquire_daemonlock(int closeflag)
 253 {
 254         static  FILE    *fp = NULL;
 255
 256         if (closeflag && fp) {
 257                 fclose(fp);
 258                 fp = NULL;
 259                 return;
 260         }
 261
 262         if (!fp) {
 263                 char    pidfile[MAX_FNAME];
 264                 char    buf[MAX_TEMPSTR];
 265                 int     fd, otherpid;
 266
 267                 (void) snprintf(pidfile, sizeof(pidfile), PIDFILE, PIDDIR);
 268                 if ((-1 == (fd = open(pidfile, O_RDWR|O_CREAT, 0644)))
 269                     || (NULL == (fp = fdopen(fd, "r+")))
 270                     ) {
 271                         snprintf(buf, sizeof(buf),
 272                                 "can't open or create %s: %s",
 273                                 pidfile, strerror(errno));
 274                         warnx(buf);
 275                         log_it("CRON", getpid(), "DEATH", buf);
 276                         exit(ERROR_EXIT);
 277                 }
 278
 279                 if (flock(fd, LOCK_EX|LOCK_NB) < OK) {
 280                         int save_errno = errno;
 281
 282                         fscanf(fp, "%d", &otherpid);
 283                         snprintf(buf, sizeof(buf),
 284                                 "can't lock %s, otherpid may be %d: %s",
 285                                 pidfile, otherpid, strerror(save_errno));
 286                         warnx(buf);
 287                         log_it("CRON", getpid(), "DEATH", buf);
 288                         exit(ERROR_EXIT);
 289                 }
 290
 291                 (void) fcntl(fd, F_SETFD, 1);
 292         }
 293
 294         rewind(fp);
 295         fprintf(fp, "%d\n", getpid());
 296         fflush(fp);
 297         (void) ftruncate(fileno(fp), ftell(fp));
 298
 299         /* abandon fd and fp even though the file is open. we need to
 300          * keep it open and locked, but we don't need the handles elsewhere.
 301          */
 302 }
 303
 304 /* get_char(file) : like getc() but increment LineNumber on newlines
 305  */
 306 int
 307 get_char(FILE *file)
 308 {
 309         int     ch;
 310
 311         ch = getc(file);
 312         if (ch == '\n')
 313                 Set_LineNum(LineNumber + 1)
 314         return ch;
 315 }
 316
 317
 318 /* unget_char(ch, file) : like ungetc but do LineNumber processing
 319  */
 320 void
 321 unget_char(int ch, FILE *file)
 322 {
 323         ungetc(ch, file);
 324         if (ch == '\n')
 325                 Set_LineNum(LineNumber - 1)
 326 }
 327
 328
 329 /* get_string(str, max, file, termstr) : like fgets() but
 330  *              (1) has terminator string which should include \n
 331  *              (2) will always leave room for the null
 332  *              (3) uses get_char() so LineNumber will be accurate
 333  *              (4) returns EOF or terminating character, whichever
 334  */
 335 int
 336 get_string(char *string, int size, FILE *file, const char *terms)
 337 {
 338         int     ch;
 339
 340         while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
 341                 if (size > 1) {
 342                         *string++ = (char) ch;
 343                         size--;
 344                 }
 345         }
 346
 347         if (size > 0)
 348                 *string = '\0';
 349
 350         return ch;
 351 }
 352
 353
 354 /* skip_comments(file) : read past comment (if any)
 355  */
 356 void
 357 skip_comments(FILE *file)
 358 {
 359         int     ch;
 360
 361         while (EOF != (ch = get_char(file))) {
 362                 /* ch is now the first character of a line.
 363                  */
 364
 365                 while (ch == ' ' || ch == '\t')
 366                         ch = get_char(file);
 367
 368                 if (ch == EOF)
 369                         break;
 370
 371                 /* ch is now the first non-blank character of a line.
 372                  */
 373
 374                 if (ch != '\n' && ch != '#')
 375                         break;
 376
 377                 /* ch must be a newline or comment as first non-blank
 378                  * character on a line.
 379                  */
 380
 381                 while (ch != '\n' && ch != EOF)
 382                         ch = get_char(file);
 383
 384                 /* ch is now the newline of a line which we're going to
 385                  * ignore.
 386                  */
 387         }
 388         if (ch != EOF)
 389                 unget_char(ch, file);
 390 }
 391
 392
 393 /* int in_file(char *string, FILE *file)
 394  *      return TRUE if one of the lines in file matches string exactly,
 395  *      FALSE otherwise.
 396  */
 397 static int
 398 in_file(char *string, FILE *file)
 399 {
 400         char line[MAX_TEMPSTR];
 401
 402         rewind(file);
 403         while (fgets(line, MAX_TEMPSTR, file)) {
 404                 if (line[0] != '\0')
 405                         line[strlen(line)-1] = '\0';
 406                 if (0 == strcmp(line, string))
 407                         return TRUE;
 408         }
 409         return FALSE;
 410 }
 411
 412
 413 /* int allowed(char *username)
 414  *      returns TRUE if (ALLOW_FILE exists and user is listed)
 415  *      or (DENY_FILE exists and user is NOT listed)
 416  *      or (neither file exists but user=="root" so it's okay)
 417  */
 418 int
 419 allowed(char *username)
 420 {
 421         static int      init = FALSE;
 422         static FILE     *allow, *deny;
 423
 424         if (!init) {
 425                 init = TRUE;
 426 #if defined(ALLOW_FILE) && defined(DENY_FILE)
 427                 allow = fopen(ALLOW_FILE, "r");
 428                 deny = fopen(DENY_FILE, "r");
 429                 Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
 430                 if (allow)
 431                         (void)fcntl(fileno(allow), F_SETFD, FD_CLOEXEC);
 432                 if (deny)
 433                         (void)fcntl(fileno(deny), F_SETFD, FD_CLOEXEC);
 434 #else
 435                 allow = NULL;
 436                 deny = NULL;
 437 #endif
 438         }
 439
 440         if (allow)
 441                 return (in_file(username, allow));
 442         if (deny)
 443                 return (!in_file(username, deny));
 444
 445 #if defined(ALLOW_ONLY_ROOT)
 446         return (strcmp(username, ROOT_USER) == 0);
 447 #else
 448         return TRUE;
 449 #endif
 450 }
 451
 452
 453 void
 454 log_it(const char *username, int xpid, const char *event, const char *detail)
 455 {
 456         PID_T                   pid = xpid;
 457 #if defined(LOG_FILE)
 458         char                    *msg;
 459         size_t                  msglen;
 460         TIME_T                  now = time((TIME_T) 0);
 461         struct tm       *t = localtime(&now);
 462 #endif /*LOG_FILE*/
 463
 464 #if defined(SYSLOG)
 465         static int              syslog_open = 0;
 466 #endif
 467
 468 #if defined(LOG_FILE)
 469         /* we assume that MAX_TEMPSTR will hold the date, time, &punctuation.
 470          */
 471         msglen = strlen(username) + strlen(event) + strlen(detail) +
 472             MAX_TEMPSTR;
 473         msg = malloc(msglen);
 474
 475         if (LogFD < OK) {
 476                 LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
 477                 if (LogFD < OK) {
 478                         warn("can't open log file %s", LOG_FILE);
 479                 } else {
 480                         (void) fcntl(LogFD, F_SETFD, 1);
 481                 }
 482         }
 483
 484         /* we have to snprintf() it because fprintf() doesn't always write
 485          * everything out in one chunk and this has to be atomically appended
 486          * to the log file.
 487          */
 488         snprintf(msg, msglen, "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n",
 489                 username,
 490                 t->tm_mon+1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, pid,
 491                 event, detail);
 492
 493         /* we have to run strlen() because sprintf() returns (char*) on old BSD
 494          */
 495         if (LogFD < OK || write(LogFD, msg, strlen(msg)) < OK) {
 496                 if (LogFD >= OK)
 497                         warn("can't write to log file");
 498                 write(STDERR, msg, strlen(msg));
 499         }
 500
 501         free(msg);
 502 #endif /*LOG_FILE*/
 503
 504 #if defined(SYSLOG)
 505         if (!syslog_open) {
 506                 /* we don't use LOG_PID since the pid passed to us by
 507                  * our client may not be our own.  therefore we want to
 508                  * print the pid ourselves.
 509                  */
 510 # ifdef LOG_DAEMON
 511                 openlog(getprogname(), LOG_PID, LOG_CRON);
 512 # else
 513                 openlog(getprogname(), LOG_PID);
 514 # endif
 515                 syslog_open = TRUE;             /* assume openlog success */
 516         }
 517
 518         syslog(LOG_INFO, "(%s) %s (%s)\n", username, event, detail);
 519
 520 #endif /*SYSLOG*/
 521
 522 #if DEBUGGING
 523         if (DebugFlags) {
 524                 fprintf(stderr, "log_it: (%s %d) %s (%s)\n",
 525                         username, pid, event, detail);
 526         }
 527 #endif
 528 }
 529
 530
 531 void
 532 log_close(void) {
 533         if (LogFD != ERR) {
 534                 close(LogFD);
 535                 LogFD = ERR;
 536         }
 537 }
 538
 539
 540 /* two warnings:
 541  *      (1) this routine is fairly slow
 542  *      (2) it returns a pointer to static storage
 543  */
 544 char *
 545 first_word(char *s, /* string we want the first word of */
 546            const char *t  /* terminators, implicitly including \0 */)
 547 {
 548         static char retbuf[2][MAX_TEMPSTR + 1]; /* sure wish C had GC */
 549         static int retsel = 0;
 550         char *rb, *rp;
 551
 552         /* select a return buffer */
 553         retsel = 1-retsel;
 554         rb = &retbuf[retsel][0];
 555         rp = rb;
 556
 557         /* skip any leading terminators */
 558         while (*s && (NULL != strchr(t, *s))) {
 559                 s++;
 560         }
 561
 562         /* copy until next terminator or full buffer */
 563         while (*s && (NULL == strchr(t, *s)) && (rp < &rb[MAX_TEMPSTR])) {
 564                 *rp++ = *s++;
 565         }
 566
 567         /* finish the return-string and return it */
 568         *rp = '\0';
 569         return rb;
 570 }
 571
 572
 573 /* warning:
 574  *      heavily ascii-dependent.
 575  */
 576 static void
 577 mkprint(char *dst, unsigned char *src, int len)
 578 {
 579         while(len > 0 && isblank((unsigned char) *src))
 580                 len--, src++;
 581
 582         strvisx(dst, src, len, VIS_TAB|VIS_NL);
 583 }
 584
 585
 586 /* warning:
 587  *      returns a pointer to malloc'd storage, you must call free yourself.
 588  */
 589 char *
 590 mkprints(unsigned char *src, unsigned int len)
 591 {
 592         char *dst = malloc(len*4 + 1);
 593
 594         mkprint(dst, src, len);
 595
 596         return dst;
 597 }
 598
 599
 600 #ifdef MAIL_DATE
 601 /* Sat, 27 Feb 1993 11:44:51 -0800 (CST)
 602  * 1234567890123456789012345678901234567
 603  */
 604 char *
 605 arpadate(time_t *clock)
 606 {
 607         static char ret[64];    /* zone name might be >3 chars */
 608         time_t t = clock ? *clock : time(NULL);
 609         struct tm *tm = localtime(&t);
 610         int hours = tm->tm_gmtoff / 3600;
 611         int minutes = (tp->tm_gmtoff - (hours * 3600)) / 60;
 612
 613         if (minutes < 0)
 614                 minutes = -minutes;
 615
 616         (void)strftime(ret, sizeof(ret), "%a, %e %b %Y %T ????? (%Z)", &tm);
 617         (void)snprintf(strchr(ret, '?'), "% .2d%.2d", hours, minutes);
 618         ret[sizeof(ret) - 1] = '\0';
 619         return ret;
 620 }
 621 #endif /*MAIL_DATE*/
 622
 623
 624 #ifdef HAVE_SAVED_UIDS
 625 static int save_euid;
 626 int swap_uids(void) { save_euid = geteuid(); return seteuid(getuid()); }
 627 #if 0
 628 int swap_uids_back() { return seteuid(save_euid); }
 629 #endif
 630 #else /*HAVE_SAVED_UIDS*/
 631 int swap_uids(void) { return setreuid(geteuid(), getuid()); }
 632 #if 0
 633 int swap_uids_back() { return swap_uids(); }
 634 #endif
 635 #endif /*HAVE_SAVED_UIDS*/