libexec/cron/misc.c

   1 /* Copyright 1988,1990,1993 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 char rcsid[] = "$Id: misc.c,v 1.1 1994/01/05 20:40:15 jtc Exp $";
  20 #endif
  21
  22 /* vix 26jan87 [RCS has the rest of the log]
  23  * vix 30dec86 [written]
  24  */
  25
  26
  27 #include "cron.h"
  28 #include "externs.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 <errno.h>
  37 #include <string.h>
  38 #include <fcntl.h>
  39 #if defined(SYSLOG)
  40 # include <syslog.h>
  41 #endif
  42
  43
  44 #if defined(LOG_DAEMON) && !defined(LOG_CRON)
  45 #define LOG_CRON LOG_DAEMON
  46 #endif
  47
  48
  49 int
  50 strcmp_until(left, right, until)
  51         char    *left;
  52         char    *right;
  53         int     until;
  54 {
  55         register int    diff;
  56
  57         while (*left && *left != until && *left == *right) {
  58                 left++;
  59                 right++;
  60         }
  61
  62         if ((*left=='\0' || *left == until) &&
  63             (*right=='\0' || *right == until)) {
  64                 diff = 0;
  65         } else {
  66                 diff = *left - *right;
  67         }
  68
  69         return diff;
  70 }
  71
  72
  73 /* strdtb(s) - delete trailing blanks in string 's' and return new length
  74  */
  75 int
  76 strdtb(s)
  77         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(flags)
 106         char    *flags;
 107 {
 108         /* debug flags are of the form    flag[,flag ...]
 109          *
 110          * if an error occurs, print a message to stdout and return FALSE.
 111          * otherwise return TRUE after setting ERROR_FLAGS.
 112          */
 113
 114 #if !DEBUGGING
 115
 116         printf("this program was compiled without debugging enabled\n");
 117         return FALSE;
 118
 119 #else /* DEBUGGING */
 120
 121         char    *pc = flags;
 122
 123         DebugFlags = 0;
 124
 125         while (*pc) {
 126                 char    **test;
 127                 int     mask;
 128
 129                 /* try to find debug flag name in our list.
 130                  */
 131                 for (   test = DebugFlagNames, mask = 1;
 132                         *test && strcmp_until(*test, pc, ',');
 133                         test++, mask <<= 1
 134                     )
 135                         ;
 136
 137                 if (!*test) {
 138                         fprintf(stderr,
 139                                 "unrecognized debug flag <%s> <%s>\n",
 140                                 flags, pc);
 141                         return FALSE;
 142                 }
 143
 144                 DebugFlags |= mask;
 145
 146                 /* skip to the next flag
 147                  */
 148                 while (*pc && *pc != ',')
 149                         pc++;
 150                 if (*pc == ',')
 151                         pc++;
 152         }
 153
 154         if (DebugFlags) {
 155                 int     flag;
 156
 157                 fprintf(stderr, "debug flags enabled:");
 158
 159                 for (flag = 0;  DebugFlagNames[flag];  flag++)
 160                         if (DebugFlags & (1 << flag))
 161                                 fprintf(stderr, " %s", DebugFlagNames[flag]);
 162                 fprintf(stderr, "\n");
 163         }
 164
 165         return TRUE;
 166
 167 #endif /* DEBUGGING */
 168 }
 169
 170
 171 void
 172 set_cron_uid()
 173 {
 174 #if defined(BSD) || defined(POSIX)
 175         if (seteuid(ROOT_UID) < OK) {
 176                 perror("seteuid");
 177                 exit(ERROR_EXIT);
 178         }
 179 #else
 180         if (setuid(ROOT_UID) < OK) {
 181                 perror("setuid");
 182                 exit(ERROR_EXIT);
 183         }
 184 #endif
 185 }
 186
 187
 188 void
 189 set_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                 perror(CRONDIR);
 197                 if (OK == mkdir(CRONDIR, 0700)) {
 198                         fprintf(stderr, "%s: created\n", CRONDIR);
 199                         stat(CRONDIR, &sb);
 200                 } else {
 201                         fprintf(stderr, "%s: ", CRONDIR);
 202                         perror("mkdir");
 203                         exit(ERROR_EXIT);
 204                 }
 205         }
 206         if (!(sb.st_mode & S_IFDIR)) {
 207                 fprintf(stderr, "'%s' is not a directory, bailing out.\n",
 208                         CRONDIR);
 209                 exit(ERROR_EXIT);
 210         }
 211         if (chdir(CRONDIR) < OK) {
 212                 fprintf(stderr, "cannot chdir(%s), bailing out.\n", CRONDIR);
 213                 perror(CRONDIR);
 214                 exit(ERROR_EXIT);
 215         }
 216
 217         /* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
 218          */
 219         if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
 220                 perror(SPOOL_DIR);
 221                 if (OK == mkdir(SPOOL_DIR, 0700)) {
 222                         fprintf(stderr, "%s: created\n", SPOOL_DIR);
 223                         stat(SPOOL_DIR, &sb);
 224                 } else {
 225                         fprintf(stderr, "%s: ", SPOOL_DIR);
 226                         perror("mkdir");
 227                         exit(ERROR_EXIT);
 228                 }
 229         }
 230         if (!(sb.st_mode & S_IFDIR)) {
 231                 fprintf(stderr, "'%s' is not a directory, bailing out.\n",
 232                         SPOOL_DIR);
 233                 exit(ERROR_EXIT);
 234         }
 235 }
 236
 237
 238 /* acquire_daemonlock() - write our PID into /etc/cron.pid, unless
 239  *      another daemon is already running, which we detect here.
 240  *
 241  * note: main() calls us twice; once before forking, once after.
 242  *      we maintain static storage of the file pointer so that we
 243  *      can rewrite our PID into the PIDFILE after the fork.
 244  *
 245  * it would be great if fflush() disassociated the file buffer.
 246  */
 247 void
 248 acquire_daemonlock(closeflag)
 249         int closeflag;
 250 {
 251         static  FILE    *fp = NULL;
 252
 253         if (closeflag && fp) {
 254                 fclose(fp);
 255                 fp = NULL;
 256                 return;
 257         }
 258
 259         if (!fp) {
 260                 char    pidfile[MAX_FNAME];
 261                 char    buf[MAX_TEMPSTR];
 262                 int     otherpid, fd;
 263
 264                 (void) sprintf(pidfile, PIDFILE, PIDDIR);
 265                 if ((-1 == (fd = open(pidfile, O_RDWR|O_CREAT, 0644)))
 266                     || (NULL == (fp = fdopen(fd, "r+")))
 267                     ) {
 268                         sprintf(buf, "can't open or create %s: %s",
 269                                 pidfile, strerror(errno));
 270                         fprintf(stderr, "%s: %s\n", ProgramName, buf);
 271                         log_it("CRON", getpid(), "DEATH", buf);
 272                         exit(ERROR_EXIT);
 273                 }
 274
 275                 if (flock(fd, LOCK_EX|LOCK_NB) < OK) {
 276                         int save_errno = errno;
 277
 278                         fscanf(fp, "%d", &otherpid);
 279                         sprintf(buf, "can't lock %s, otherpid may be %d: %s",
 280                                 pidfile, otherpid, strerror(save_errno));
 281                         fprintf(stderr, "%s: %s\n", ProgramName, buf);
 282                         log_it("CRON", getpid(), "DEATH", buf);
 283                         exit(ERROR_EXIT);
 284                 }
 285
 286                 (void) fcntl(fd, F_SETFD, 1);
 287         }
 288
 289         rewind(fp);
 290         fprintf(fp, "%d\n", getpid());
 291         fflush(fp);
 292         (void) ftruncate(fileno(fp), ftell(fp));
 293
 294         /* abandon fd and fp even though the file is open. we need to
 295          * keep it open and locked, but we don't need the handles elsewhere.
 296          */
 297 }
 298
 299 /* get_char(file) : like getc() but increment LineNumber on newlines
 300  */
 301 int
 302 get_char(file)
 303         FILE    *file;
 304 {
 305         int     ch;
 306
 307         ch = getc(file);
 308         if (ch == '\n')
 309                 Set_LineNum(LineNumber + 1)
 310         return ch;
 311 }
 312
 313
 314 /* unget_char(ch, file) : like ungetc but do LineNumber processing
 315  */
 316 void
 317 unget_char(ch, file)
 318         int     ch;
 319         FILE    *file;
 320 {
 321         ungetc(ch, file);
 322         if (ch == '\n')
 323                 Set_LineNum(LineNumber - 1)
 324 }
 325
 326
 327 /* get_string(str, max, file, termstr) : like fgets() but
 328  *              (1) has terminator string which should include \n
 329  *              (2) will always leave room for the null
 330  *              (3) uses get_char() so LineNumber will be accurate
 331  *              (4) returns EOF or terminating character, whichever
 332  */
 333 int
 334 get_string(string, size, file, terms)
 335         char    *string;
 336         int     size;
 337         FILE    *file;
 338         char    *terms;
 339 {
 340         int     ch;
 341
 342         while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
 343                 if (size > 1) {
 344                         *string++ = (char) ch;
 345                         size--;
 346                 }
 347         }
 348
 349         if (size > 0)
 350                 *string = '\0';
 351
 352         return ch;
 353 }
 354
 355
 356 /* skip_comments(file) : read past comment (if any)
 357  */
 358 void
 359 skip_comments(file)
 360         FILE    *file;
 361 {
 362         int     ch;
 363
 364         while (EOF != (ch = get_char(file))) {
 365                 /* ch is now the first character of a line.
 366                  */
 367
 368                 while (ch == ' ' || ch == '\t')
 369                         ch = get_char(file);
 370
 371                 if (ch == EOF)
 372                         break;
 373
 374                 /* ch is now the first non-blank character of a line.
 375                  */
 376
 377                 if (ch != '\n' && ch != '#')
 378                         break;
 379
 380                 /* ch must be a newline or comment as first non-blank
 381                  * character on a line.
 382                  */
 383
 384                 while (ch != '\n' && ch != EOF)
 385                         ch = get_char(file);
 386
 387                 /* ch is now the newline of a line which we're going to
 388                  * ignore.
 389                  */
 390         }
 391         if (ch != EOF)
 392                 unget_char(ch, file);
 393 }
 394
 395
 396 /* int in_file(char *string, FILE *file)
 397  *      return TRUE if one of the lines in file matches string exactly,
 398  *      FALSE otherwise.
 399  */
 400 static int
 401 in_file(string, file)
 402         char *string;
 403         FILE *file;
 404 {
 405         char line[MAX_TEMPSTR];
 406
 407         rewind(file);
 408         while (fgets(line, MAX_TEMPSTR, file)) {
 409                 if (line[0] != '\0')
 410                         line[strlen(line)-1] = '\0';
 411                 if (0 == strcmp(line, string))
 412                         return TRUE;
 413         }
 414         return FALSE;
 415 }
 416
 417
 418 /* int allowed(char *username)
 419  *      returns TRUE if (ALLOW_FILE exists and user is listed)
 420  *      or (DENY_FILE exists and user is NOT listed)
 421  *      or (neither file exists but user=="root" so it's okay)
 422  */
 423 int
 424 allowed(username)
 425         char *username;
 426 {
 427         static int      init = FALSE;
 428         static FILE     *allow, *deny;
 429
 430         if (!init) {
 431                 init = TRUE;
 432 #if defined(ALLOW_FILE) && defined(DENY_FILE)
 433                 allow = fopen(ALLOW_FILE, "r");
 434                 deny = fopen(DENY_FILE, "r");
 435                 Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
 436 #else
 437                 allow = NULL;
 438                 deny = NULL;
 439 #endif
 440         }
 441
 442         if (allow)
 443                 return (in_file(username, allow));
 444         if (deny)
 445                 return (!in_file(username, deny));
 446
 447 #if defined(ALLOW_ONLY_ROOT)
 448         return (strcmp(username, ROOT_USER) == 0);
 449 #else
 450         return TRUE;
 451 #endif
 452 }
 453
 454
 455 void
 456 log_it(username, pid, event, detail)
 457         char    *username;
 458         int     pid;
 459         char    *event;
 460         char    *detail;
 461 {
 462 #if defined(LOG_FILE)
 463         char                    *msg;
 464         TIME_T                  now = time((TIME_T) 0);
 465         register struct tm      *t = localtime(&now);
 466         static int              log_fd = -1;
 467 #endif /*LOG_FILE*/
 468
 469 #if defined(SYSLOG)
 470         static int              syslog_open = 0;
 471 #endif
 472
 473 #if defined(LOG_FILE)
 474         /* we assume that MAX_TEMPSTR will hold the date, time, &punctuation.
 475          */
 476         msg = malloc(strlen(username)
 477                      + strlen(event)
 478                      + strlen(detail)
 479                      + MAX_TEMPSTR);
 480
 481         if (log_fd < OK) {
 482                 log_fd = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
 483                 if (log_fd < OK) {
 484                         fprintf(stderr, "%s: can't open log file\n",
 485                                 ProgramName);
 486                         perror(LOG_FILE);
 487                 } else {
 488                         (void) fcntl(log_fd, F_SETFD, 1);
 489                 }
 490         }
 491
 492         /* we have to sprintf() it because fprintf() doesn't always write
 493          * everything out in one chunk and this has to be atomically appended
 494          * to the log file.
 495          */
 496         sprintf(msg, "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n",
 497                 username,
 498                 t->tm_mon+1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, pid,
 499                 event, detail);
 500
 501         /* we have to run strlen() because sprintf() returns (char*) on old BSD
 502          */
 503         if (log_fd < OK || write(log_fd, msg, strlen(msg)) < OK) {
 504                 fprintf(stderr, "%s: can't write to log file\n", ProgramName);
 505                 if (log_fd >= OK)
 506                         perror(LOG_FILE);
 507                 write(STDERR, msg, strlen(msg));
 508         }
 509
 510         free(msg);
 511 #endif /*LOG_FILE*/
 512
 513 #if defined(SYSLOG)
 514         if (!syslog_open) {
 515                 /* we don't use LOG_PID since the pid passed to us by
 516                  * our client may not be our own.  therefore we want to
 517                  * print the pid ourselves.
 518                  */
 519 # ifdef LOG_DAEMON
 520                 openlog(ProgramName, LOG_PID, LOG_CRON);
 521 # else
 522                 openlog(ProgramName, LOG_PID);
 523 # endif
 524                 syslog_open = TRUE;             /* assume openlog success */
 525         }
 526
 527         syslog(LOG_INFO, "(%s) %s (%s)\n", username, event, detail);
 528
 529 #endif /*SYSLOG*/
 530
 531 #if DEBUGGING
 532         if (DebugFlags) {
 533                 fprintf(stderr, "log_it: (%s %d) %s (%s)\n",
 534                         username, pid, event, detail);
 535         }
 536 #endif
 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(s, t)
 546         register char *s;       /* string we want the first word of */
 547         register char *t;       /* terminators, implicitly including \0 */
 548 {
 549         static char retbuf[2][MAX_TEMPSTR + 1]; /* sure wish C had GC */
 550         static int retsel = 0;
 551         register char *rb, *rp;
 552
 553         /* select a return buffer */
 554         retsel = 1-retsel;
 555         rb = &retbuf[retsel][0];
 556         rp = rb;
 557
 558         /* skip any leading terminators */
 559         while (*s && (NULL != strchr(t, *s))) {
 560                 s++;
 561         }
 562
 563         /* copy until next terminator or full buffer */
 564         while (*s && (NULL == strchr(t, *s)) && (rp < &rb[MAX_TEMPSTR])) {
 565                 *rp++ = *s++;
 566         }
 567
 568         /* finish the return-string and return it */
 569         *rp = '\0';
 570         return rb;
 571 }
 572
 573
 574 /* warning:
 575  *      heavily ascii-dependent.
 576  */
 577 void
 578 mkprint(dst, src, len)
 579         register char *dst;
 580         register unsigned char *src;
 581         register int len;
 582 {
 583         while (len-- > 0)
 584         {
 585                 register unsigned char ch = *src++;
 586
 587                 if (ch < ' ') {                 /* control character */
 588                         *dst++ = '^';
 589                         *dst++ = ch + '@';
 590                 } else if (ch < 0177) {         /* printable */
 591                         *dst++ = ch;
 592                 } else if (ch == 0177) {        /* delete/rubout */
 593                         *dst++ = '^';
 594                         *dst++ = '?';
 595                 } else {                        /* parity character */
 596                         sprintf(dst, "\\%03o", ch);
 597                         dst += 4;
 598                 }
 599         }
 600         *dst = '\0';
 601 }
 602
 603
 604 /* warning:
 605  *      returns a pointer to malloc'd storage, you must call free yourself.
 606  */
 607 char *
 608 mkprints(src, len)
 609         register unsigned char *src;
 610         register unsigned int len;
 611 {
 612         register char *dst = malloc(len*4 + 1);
 613
 614         mkprint(dst, src, len);
 615
 616         return dst;
 617 }
 618
 619
 620 #ifdef MAIL_DATE
 621 /* Sat, 27 Feb 93 11:44:51 CST
 622  * 123456789012345678901234567
 623  */
 624 char *
 625 arpadate(clock)
 626         time_t *clock;
 627 {
 628         time_t t = clock ?*clock :time(0L);
 629         struct tm *tm = localtime(&t);
 630         static char ret[30];    /* zone name might be >3 chars */
 631
 632         (void) sprintf(ret, "%s, %2d %s %2d %02d:%02d:%02d %s",
 633                        DowNames[tm->tm_wday],
 634                        tm->tm_mday,
 635                        MonthNames[tm->tm_mon],
 636                        tm->tm_year,
 637                        tm->tm_hour,
 638                        tm->tm_min,
 639                        tm->tm_sec,
 640                        TZONE(*tm));
 641         return ret;
 642 }
 643 #endif /*MAIL_DATE*/
 644
 645
 646 #ifdef HAVE_SAVED_SUIDS
 647 static int save_euid;
 648 int swap_uids() { save_euid = geteuid(); return seteuid(getuid()); }
 649 int swap_uids_back() { return seteuid(save_euid); }
 650 #else /*HAVE_SAVED_UIDS*/
 651 int swap_uids() { return setreuid(geteuid(), getuid()); }
 652 int swap_uids_back() { return swap_uids(); }
 653 #endif /*HAVE_SAVED_UIDS*/