usr.sbin/cron/lib/misc.c

   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  * $FreeBSD: src/usr.sbin/cron/lib/misc.c,v 1.8.2.2 2002/04/28 22:45:53 dwmalone Exp $
  18  * $DragonFly: src/usr.sbin/cron/lib/misc.c,v 1.5 2004/12/18 22:48:03 swildner Exp $
  19  */
  20
  21 /* vix 26jan87 [RCS has the rest of the log]
  22  * vix 30dec86 [written]
  23  */
  24
  25
  26 #include "cron.h"
  27 #if SYS_TIME_H
  28 # include <sys/time.h>
  29 #else
  30 # include <time.h>
  31 #endif
  32 #include <sys/file.h>
  33 #include <sys/stat.h>
  34 #include <err.h>
  35 #include <errno.h>
  36 #include <string.h>
  37 #include <fcntl.h>
  38 #if defined(SYSLOG)
  39 # include <syslog.h>
  40 #endif
  41
  42
  43 #if defined(LOG_DAEMON) && !defined(LOG_CRON)
  44 #define LOG_CRON LOG_DAEMON
  45 #endif
  46
  47
  48 static int              LogFD = ERR;
  49
  50
  51 int
  52 strcmp_until(char *left, char *right, int until)
  53 {
  54         int diff;
  55
  56         while (*left && *left != until && *left == *right) {
  57                 left++;
  58                 right++;
  59         }
  60
  61         if ((*left=='\0' || *left == until) &&
  62             (*right=='\0' || *right == until)) {
  63                 diff = 0;
  64         } else {
  65                 diff = *left - *right;
  66         }
  67
  68         return diff;
  69 }
  70
  71
  72 /* strdtb(s) - delete trailing blanks in string 's' and return new length
  73  */
  74 int
  75 strdtb(char *s)
  76 {
  77         char    *x = s;
  78
  79         /* scan forward to the null
  80          */
  81         while (*x)
  82                 x++;
  83
  84         /* scan backward to either the first character before the string,
  85          * or the last non-blank in the string, whichever comes first.
  86          */
  87         do      {x--;}
  88         while (x >= s && isspace(*x));
  89
  90         /* one character beyond where we stopped above is where the null
  91          * goes.
  92          */
  93         *++x = '\0';
  94
  95         /* the difference between the position of the null character and
  96          * the position of the first character of the string is the length.
  97          */
  98         return x - s;
  99 }
 100
 101
 102 int
 103 set_debug_flags(char *flags)
 104 {
 105         /* debug flags are of the form    flag[,flag ...]
 106          *
 107          * if an error occurs, print a message to stdout and return FALSE.
 108          * otherwise return TRUE after setting ERROR_FLAGS.
 109          */
 110
 111 #if !DEBUGGING
 112
 113         printf("this program was compiled without debugging enabled\n");
 114         return FALSE;
 115
 116 #else /* DEBUGGING */
 117
 118         char    *pc = flags;
 119
 120         DebugFlags = 0;
 121
 122         while (*pc) {
 123                 char    **test;
 124                 int     mask;
 125
 126                 /* try to find debug flag name in our list.
 127                  */
 128                 for (   test = DebugFlagNames, mask = 1;
 129                         *test && strcmp_until(*test, pc, ',');
 130                         test++, mask <<= 1
 131                     )
 132                         ;
 133
 134                 if (!*test) {
 135                         fprintf(stderr,
 136                                 "unrecognized debug flag <%s> <%s>\n",
 137                                 flags, pc);
 138                         return FALSE;
 139                 }
 140
 141                 DebugFlags |= mask;
 142
 143                 /* skip to the next flag
 144                  */
 145                 while (*pc && *pc != ',')
 146                         pc++;
 147                 if (*pc == ',')
 148                         pc++;
 149         }
 150
 151         if (DebugFlags) {
 152                 int     flag;
 153
 154                 fprintf(stderr, "debug flags enabled:");
 155
 156                 for (flag = 0;  DebugFlagNames[flag];  flag++)
 157                         if (DebugFlags & (1 << flag))
 158                                 fprintf(stderr, " %s", DebugFlagNames[flag]);
 159                 fprintf(stderr, "\n");
 160         }
 161
 162         return TRUE;
 163
 164 #endif /* DEBUGGING */
 165 }
 166
 167
 168 void
 169 set_cron_uid(void)
 170 {
 171 #if defined(BSD) || defined(POSIX)
 172         if (seteuid(ROOT_UID) < OK)
 173                 err(ERROR_EXIT, "seteuid");
 174 #else
 175         if (setuid(ROOT_UID) < OK)
 176                 err(ERROR_EXIT, "setuid");
 177 #endif
 178 }
 179
 180
 181 void
 182 set_cron_cwd(void)
 183 {
 184         struct stat     sb;
 185
 186         /* first check for CRONDIR ("/var/cron" or some such)
 187          */
 188         if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
 189                 warn("%s", CRONDIR);
 190                 if (OK == mkdir(CRONDIR, 0700)) {
 191                         warnx("%s: created", CRONDIR);
 192                         stat(CRONDIR, &sb);
 193                 } else {
 194                         err(ERROR_EXIT, "%s: mkdir", CRONDIR);
 195                 }
 196         }
 197         if (!(sb.st_mode & S_IFDIR))
 198                 err(ERROR_EXIT, "'%s' is not a directory, bailing out", CRONDIR);
 199         if (chdir(CRONDIR) < OK)
 200                 err(ERROR_EXIT, "cannot chdir(%s), bailing out", CRONDIR);
 201
 202         /* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
 203          */
 204         if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
 205                 warn("%s", SPOOL_DIR);
 206                 if (OK == mkdir(SPOOL_DIR, 0700)) {
 207                         warnx("%s: created", SPOOL_DIR);
 208                         stat(SPOOL_DIR, &sb);
 209                 } else {
 210                         err(ERROR_EXIT, "%s: mkdir", SPOOL_DIR);
 211                 }
 212         }
 213         if (!(sb.st_mode & S_IFDIR))
 214                 err(ERROR_EXIT, "'%s' is not a directory, bailing out", SPOOL_DIR);
 215 }
 216
 217
 218 /* acquire_daemonlock() - write our PID into /etc/cron.pid, unless
 219  *      another daemon is already running, which we detect here.
 220  *
 221  * note: main() calls us twice; once before forking, once after.
 222  *      we maintain static storage of the file pointer so that we
 223  *      can rewrite our PID into the PIDFILE after the fork.
 224  *
 225  * it would be great if fflush() disassociated the file buffer.
 226  */
 227 void
 228 acquire_daemonlock(int closeflag)
 229 {
 230         static  FILE    *fp = NULL;
 231
 232         if (closeflag && fp) {
 233                 fclose(fp);
 234                 fp = NULL;
 235                 return;
 236         }
 237
 238         if (!fp) {
 239                 char    pidfile[MAX_FNAME];
 240                 char    buf[MAX_TEMPSTR];
 241                 int     fd, otherpid;
 242
 243                 sprintf(pidfile, PIDFILE, PIDDIR);
 244                 if ((-1 == (fd = open(pidfile, O_RDWR|O_CREAT, 0644)))
 245                     || (NULL == (fp = fdopen(fd, "r+")))
 246                     ) {
 247                         sprintf(buf, "can't open or create %s: %s",
 248                                 pidfile, strerror(errno));
 249                         log_it("CRON", getpid(), "DEATH", buf);
 250                         errx(ERROR_EXIT, "%s", buf);
 251                 }
 252
 253                 if (flock(fd, LOCK_EX|LOCK_NB) < OK) {
 254                         int save_errno = errno;
 255
 256                         fscanf(fp, "%d", &otherpid);
 257                         sprintf(buf, "can't lock %s, otherpid may be %d: %s",
 258                                 pidfile, otherpid, strerror(save_errno));
 259                         log_it("CRON", getpid(), "DEATH", buf);
 260                         errx(ERROR_EXIT, "%s", buf);
 261                 }
 262
 263                 fcntl(fd, F_SETFD, 1);
 264         }
 265
 266         rewind(fp);
 267         fprintf(fp, "%d\n", getpid());
 268         fflush(fp);
 269         ftruncate(fileno(fp), ftell(fp));
 270
 271         /* abandon fd and fp even though the file is open. we need to
 272          * keep it open and locked, but we don't need the handles elsewhere.
 273          */
 274 }
 275
 276 /* get_char(file) : like getc() but increment LineNumber on newlines
 277  */
 278 int
 279 get_char(FILE *file)
 280 {
 281         int     ch;
 282
 283         ch = getc(file);
 284         if (ch == '\n')
 285                 Set_LineNum(LineNumber + 1)
 286         return ch;
 287 }
 288
 289
 290 /* unget_char(ch, file) : like ungetc but do LineNumber processing
 291  */
 292 void
 293 unget_char(int ch, FILE *file)
 294 {
 295         ungetc(ch, file);
 296         if (ch == '\n')
 297                 Set_LineNum(LineNumber - 1)
 298 }
 299
 300
 301 /* get_string(str, max, file, termstr) : like fgets() but
 302  *              (1) has terminator string which should include \n
 303  *              (2) will always leave room for the null
 304  *              (3) uses get_char() so LineNumber will be accurate
 305  *              (4) returns EOF or terminating character, whichever
 306  */
 307 int
 308 get_string(char *string, int size, FILE *file, char *terms)
 309 {
 310         int     ch;
 311
 312         while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
 313                 if (size > 1) {
 314                         *string++ = (char) ch;
 315                         size--;
 316                 }
 317         }
 318
 319         if (size > 0)
 320                 *string = '\0';
 321
 322         return ch;
 323 }
 324
 325
 326 /* skip_comments(file) : read past comment (if any)
 327  */
 328 void
 329 skip_comments(FILE *file)
 330 {
 331         int     ch;
 332
 333         while (EOF != (ch = get_char(file))) {
 334                 /* ch is now the first character of a line.
 335                  */
 336
 337                 while (ch == ' ' || ch == '\t')
 338                         ch = get_char(file);
 339
 340                 if (ch == EOF)
 341                         break;
 342
 343                 /* ch is now the first non-blank character of a line.
 344                  */
 345
 346                 if (ch != '\n' && ch != '#')
 347                         break;
 348
 349                 /* ch must be a newline or comment as first non-blank
 350                  * character on a line.
 351                  */
 352
 353                 while (ch != '\n' && ch != EOF)
 354                         ch = get_char(file);
 355
 356                 /* ch is now the newline of a line which we're going to
 357                  * ignore.
 358                  */
 359         }
 360         if (ch != EOF)
 361                 unget_char(ch, file);
 362 }
 363
 364
 365 /* int in_file(char *string, FILE *file)
 366  *      return TRUE if one of the lines in file matches string exactly,
 367  *      FALSE otherwise.
 368  */
 369 static int
 370 in_file(char *string, FILE *file)
 371 {
 372         char line[MAX_TEMPSTR];
 373
 374         rewind(file);
 375         while (fgets(line, MAX_TEMPSTR, file)) {
 376                 if (line[0] != '\0')
 377                         if (line[strlen(line)-1] == '\n')
 378                                 line[strlen(line)-1] = '\0';
 379                 if (0 == strcmp(line, string))
 380                         return TRUE;
 381         }
 382         return FALSE;
 383 }
 384
 385
 386 /* int allowed(char *username)
 387  *      returns TRUE if (ALLOW_FILE exists and user is listed)
 388  *      or (DENY_FILE exists and user is NOT listed)
 389  *      or (neither file exists but user=="root" so it's okay)
 390  */
 391 int
 392 allowed(char *username)
 393 {
 394         static int      init = FALSE;
 395         static FILE     *allow, *deny;
 396
 397         if (!init) {
 398                 init = TRUE;
 399 #if defined(ALLOW_FILE) && defined(DENY_FILE)
 400                 allow = fopen(ALLOW_FILE, "r");
 401                 deny = fopen(DENY_FILE, "r");
 402                 Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
 403 #else
 404                 allow = NULL;
 405                 deny = NULL;
 406 #endif
 407         }
 408
 409         if (allow)
 410                 return (in_file(username, allow));
 411         if (deny)
 412                 return (!in_file(username, deny));
 413
 414 #if defined(ALLOW_ONLY_ROOT)
 415         return (strcmp(username, ROOT_USER) == 0);
 416 #else
 417         return TRUE;
 418 #endif
 419 }
 420
 421
 422 void
 423 log_it(char *username, int xpid, char *event, char *detail)
 424 {
 425         PID_T pid = xpid;
 426 #if defined(LOG_FILE)
 427         char *msg;
 428         TIME_T now;
 429         struct tm *t;
 430 #endif /*LOG_FILE*/
 431
 432 #if defined(SYSLOG)
 433         static int              syslog_open = 0;
 434 #endif
 435
 436 #if defined(LOG_FILE)
 437         now = time((TIME_T)0);
 438         t = localtime(&now);
 439         /* we assume that MAX_TEMPSTR will hold the date, time, &punctuation.
 440          */
 441         msg = malloc(strlen(username)
 442                      + strlen(event)
 443                      + strlen(detail)
 444                      + MAX_TEMPSTR);
 445
 446         if (msg == NULL)
 447                 warnx("failed to allocate memory for log message");
 448         else {
 449                 if (LogFD < OK) {
 450                         LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
 451                         if (LogFD < OK) {
 452                                 warn("can't open log file %s", LOG_FILE);
 453                         } else {
 454                                 fcntl(LogFD, F_SETFD, 1);
 455                         }
 456                 }
 457
 458                 /* we have to sprintf() it because fprintf() doesn't always
 459                  * write everything out in one chunk and this has to be
 460                  * atomically appended to the log file.
 461                  */
 462                 sprintf(msg, "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n",
 463                         username,
 464                         t->tm_mon+1, t->tm_mday, t->tm_hour, t->tm_min,
 465                         t->tm_sec, pid, event, detail);
 466
 467                 /* we have to run strlen() because sprintf() returns (char*)
 468                  * on old BSD.
 469                  */
 470                 if (LogFD < OK || write(LogFD, msg, strlen(msg)) < OK) {
 471                         if (LogFD >= OK)
 472                                 warn("%s", LOG_FILE);
 473                         warnx("can't write to log file");
 474                         write(STDERR, msg, strlen(msg));
 475                 }
 476
 477                 free(msg);
 478         }
 479 #endif /*LOG_FILE*/
 480
 481 #if defined(SYSLOG)
 482         if (!syslog_open) {
 483                 /* we don't use LOG_PID since the pid passed to us by
 484                  * our client may not be our own.  therefore we want to
 485                  * print the pid ourselves.
 486                  */
 487 # ifdef LOG_DAEMON
 488                 openlog(ProgramName, LOG_PID, LOG_CRON);
 489 # else
 490                 openlog(ProgramName, LOG_PID);
 491 # endif
 492                 syslog_open = TRUE;             /* assume openlog success */
 493         }
 494
 495         syslog(LOG_INFO, "(%s) %s (%s)\n", username, event, detail);
 496
 497 #endif /*SYSLOG*/
 498
 499 #if DEBUGGING
 500         if (DebugFlags) {
 501                 fprintf(stderr, "log_it: (%s %d) %s (%s)\n",
 502                         username, pid, event, detail);
 503         }
 504 #endif
 505 }
 506
 507
 508 void
 509 log_close(void) {
 510         if (LogFD != ERR) {
 511                 close(LogFD);
 512                 LogFD = ERR;
 513         }
 514 }
 515
 516
 517 /* two warnings:
 518  *      (1) this routine is fairly slow
 519  *      (2) it returns a pointer to static storage
 520  *
 521  * s    string we want the first word of
 522  * t    terminators, implicitly including \0
 523  */
 524 char *
 525 first_word(char *s, char *t)
 526 {
 527         static char retbuf[2][MAX_TEMPSTR + 1]; /* sure wish C had GC */
 528         static int retsel = 0;
 529         char *rb, *rp;
 530
 531         /* select a return buffer */
 532         retsel = 1-retsel;
 533         rb = &retbuf[retsel][0];
 534         rp = rb;
 535
 536         /* skip any leading terminators */
 537         while (*s && (NULL != strchr(t, *s))) {
 538                 s++;
 539         }
 540
 541         /* copy until next terminator or full buffer */
 542         while (*s && (NULL == strchr(t, *s)) && (rp < &rb[MAX_TEMPSTR])) {
 543                 *rp++ = *s++;
 544         }
 545
 546         /* finish the return-string and return it */
 547         *rp = '\0';
 548         return rb;
 549 }
 550
 551
 552 /* warning:
 553  *      heavily ascii-dependent.
 554  */
 555 void
 556 mkprint(char *dst, unsigned char *src, int len)
 557 {
 558         while (len-- > 0)
 559         {
 560                 unsigned char ch = *src++;
 561
 562                 if (ch < ' ') {                 /* control character */
 563                         *dst++ = '^';
 564                         *dst++ = ch + '@';
 565                 } else if (ch < 0177) {         /* printable */
 566                         *dst++ = ch;
 567                 } else if (ch == 0177) {        /* delete/rubout */
 568                         *dst++ = '^';
 569                         *dst++ = '?';
 570                 } else {                        /* parity character */
 571                         sprintf(dst, "\\%03o", ch);
 572                         dst += 4;
 573                 }
 574         }
 575         *dst = '\0';
 576 }
 577
 578
 579 /* warning:
 580  *      returns a pointer to malloc'd storage, you must call free yourself.
 581  */
 582 char *
 583 mkprints(unsigned char *src, unsigned int len)
 584 {
 585         char *dst;
 586
 587         dst = malloc(len * 4 + 1);
 588         if (dst != NULL)
 589                 mkprint(dst, src, len);
 590
 591         return dst;
 592 }
 593
 594
 595 #ifdef MAIL_DATE
 596 /* Sat, 27 Feb 93 11:44:51 CST
 597  * 123456789012345678901234567
 598  */
 599 char *
 600 arpadate(time_t *clock)
 601 {
 602         time_t t = clock ?*clock :time(0L);
 603         struct tm *tm = localtime(&t);
 604         static char ret[32];    /* zone name might be >3 chars */
 605
 606         if (tm->tm_year >= 100)
 607                 tm->tm_year += 1900;
 608
 609         snprintf(ret, sizeof(ret), "%s, %2d %s %d %02d:%02d:%02d %s",
 610                  DowNames[tm->tm_wday],
 611                  tm->tm_mday,
 612                  MonthNames[tm->tm_mon],
 613                  tm->tm_year,
 614                  tm->tm_hour,
 615                  tm->tm_min,
 616                  tm->tm_sec,
 617                  TZONE(*tm));
 618         return ret;
 619 }
 620 #endif /*MAIL_DATE*/
 621
 622
 623 #ifdef HAVE_SAVED_UIDS
 624 static int save_euid;
 625 int
 626 swap_uids(void)
 627 {
 628         save_euid = geteuid();
 629         return seteuid(getuid());
 630 }
 631 int
 632 swap_uids_back(void)
 633 {
 634
 635         return seteuid(save_euid);
 636 }
 637 #else /*HAVE_SAVED_UIDS*/
 638 int
 639 swap_uids(void)
 640 {
 641         return setreuid(geteuid(), getuid());
 642 }
 643 int
 644 swap_uids_back(void)
 645 {
 646         return swap_uids();
 647 }
 648 #endif /*HAVE_SAVED_UIDS*/