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