libexec/cron/entry.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: entry.c,v 1.1 1994/01/05 20:40:14 jtc Exp $";
  20 #endif
  21
  22 /* vix 26jan87 [RCS'd; rest of log is in RCS file]
  23  * vix 01jan87 [added line-level error recovery]
  24  * vix 31dec86 [added /step to the from-to range, per bob@acornrc]
  25  * vix 30dec86 [written]
  26  */
  27
  28
  29 #include "cron.h"
  30 #include "externs.h"
  31 #include <pwd.h>
  32
  33
  34 typedef enum ecode {
  35         e_none, e_minute, e_hour, e_dom, e_month, e_dow,
  36         e_cmd, e_timespec, e_username
  37 } ecode_e;
  38
  39 static char     get_list __P((bitstr_t *, int, int, char *[], int, FILE *)),
  40                 get_range __P((bitstr_t *, int, int, char *[], int, FILE *)),
  41                 get_number __P((int *, int, char *[], int, FILE *));
  42 static int      set_element __P((bitstr_t *, int, int, int));
  43
  44 static char *ecodes[] =
  45         {
  46                 "no error",
  47                 "bad minute",
  48                 "bad hour",
  49                 "bad day-of-month",
  50                 "bad month",
  51                 "bad day-of-week",
  52                 "bad command",
  53                 "bad time specifier",
  54                 "bad username",
  55         };
  56
  57
  58 void
  59 free_entry(e)
  60         entry   *e;
  61 {
  62         free(e->cmd);
  63         free(e);
  64 }
  65
  66
  67 entry *
  68 load_entry(file, error_func, syscron)
  69         FILE    *file;
  70         void    (*error_func)();
  71         int     syscron;
  72 {
  73         /* this function reads one crontab entry -- the next -- from a file.
  74          * it skips any leading blank lines, ignores comments, and returns
  75          * EOF if for any reason the entry can't be read and parsed.
  76          *
  77          * the entry is also parsed here.
  78          *
  79          * syntax:
  80          *   user crontab:
  81          *      minutes hours doms months dows cmd\n
  82          *   system crontab (/etc/crontab):
  83          *      minutes hours doms months dows USERNAME cmd\n
  84          */
  85
  86         ecode_e ecode = e_none;
  87         entry   *e;
  88         int     ch;
  89         char    cmd[MAX_COMMAND];
  90
  91         e = (entry *) calloc(sizeof(entry), sizeof(char));
  92
  93         Debug(DPARS, ("load_entry()...about to eat comments\n"))
  94
  95         skip_comments(file);
  96
  97         ch = get_char(file);
  98         if (ch == EOF)
  99                 return NULL;
 100
 101         /* ch is now the first useful character of a useful line.
 102          * it may be an @special or it may be the first character
 103          * of a list of minutes.
 104          */
 105
 106         if (ch == '@') {
 107                 /* all of these should be flagged and load-limited; i.e.,
 108                  * instead of @hourly meaning "0 * * * *" it should mean
 109                  * "close to the front of every hour but not 'til the
 110                  * system load is low".  Problems are: how do you know
 111                  * what "low" means? (save me from /etc/cron.conf!) and:
 112                  * how to guarantee low variance (how low is low?), which
 113                  * means how to we run roughly every hour -- seems like
 114                  * we need to keep a history or let the first hour set
 115                  * the schedule, which means we aren't load-limited
 116                  * anymore.  too much for my overloaded brain. (vix, jan90)
 117                  * HINT
 118                  */
 119                 ch = get_string(cmd, MAX_COMMAND, file, " \t\n");
 120                 if (!strcmp("reboot", cmd)) {
 121                         e->flags |= WHEN_REBOOT;
 122                 } else if (!strcmp("yearly", cmd) || !strcmp("annually", cmd)){
 123                         bit_set(e->minute, 0);
 124                         bit_set(e->hour, 0);
 125                         bit_set(e->dom, 0);
 126                         bit_set(e->month, 0);
 127                         bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
 128                 } else if (!strcmp("monthly", cmd)) {
 129                         bit_set(e->minute, 0);
 130                         bit_set(e->hour, 0);
 131                         bit_set(e->dom, 0);
 132                         bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
 133                         bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
 134                 } else if (!strcmp("weekly", cmd)) {
 135                         bit_set(e->minute, 0);
 136                         bit_set(e->hour, 0);
 137                         bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
 138                         bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
 139                         bit_set(e->dow, 0);
 140                 } else if (!strcmp("daily", cmd) || !strcmp("midnight", cmd)) {
 141                         bit_set(e->minute, 0);
 142                         bit_set(e->hour, 0);
 143                         bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
 144                         bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
 145                         bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
 146                 } else if (!strcmp("hourly", cmd)) {
 147                         bit_set(e->minute, 0);
 148                         bit_set(e->hour, (LAST_HOUR-FIRST_HOUR+1));
 149                         bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
 150                         bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
 151                         bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
 152                 } else {
 153                         ecode = e_timespec;
 154                         goto eof;
 155                 }
 156         } else {
 157                 Debug(DPARS, ("load_entry()...about to parse numerics\n"))
 158
 159                 ch = get_list(e->minute, FIRST_MINUTE, LAST_MINUTE,
 160                               PPC_NULL, ch, file);
 161                 if (ch == EOF) {
 162                         ecode = e_minute;
 163                         goto eof;
 164                 }
 165
 166                 /* hours
 167                  */
 168
 169                 ch = get_list(e->hour, FIRST_HOUR, LAST_HOUR,
 170                               PPC_NULL, ch, file);
 171                 if (ch == EOF) {
 172                         ecode = e_hour;
 173                         goto eof;
 174                 }
 175
 176                 /* DOM (days of month)
 177                  */
 178
 179                 if (ch == '*')
 180                         e->flags |= DOM_STAR;
 181                 ch = get_list(e->dom, FIRST_DOM, LAST_DOM,
 182                               PPC_NULL, ch, file);
 183                 if (ch == EOF) {
 184                         ecode = e_dom;
 185                         goto eof;
 186                 }
 187
 188                 /* month
 189                  */
 190
 191                 ch = get_list(e->month, FIRST_MONTH, LAST_MONTH,
 192                               MonthNames, ch, file);
 193                 if (ch == EOF) {
 194                         ecode = e_month;
 195                         goto eof;
 196                 }
 197
 198                 /* DOW (days of week)
 199                  */
 200
 201                 if (ch == '*')
 202                         e->flags |= DOW_STAR;
 203                 ch = get_list(e->dow, FIRST_DOW, LAST_DOW,
 204                               DowNames, ch, file);
 205                 if (ch == EOF) {
 206                         ecode = e_dow;
 207                         goto eof;
 208                 }
 209         }
 210
 211         /* make sundays equivilent */
 212         if (bit_test(e->dow, 0) || bit_test(e->dow, 7)) {
 213                 bit_set(e->dow, 0);
 214                 bit_set(e->dow, 7);
 215         }
 216
 217         /* ch is the first character of a command, or a username */
 218         unget_char(ch, file);
 219
 220         e->exec_uid = 0;                /* default to user */
 221         if (syscron) {
 222                 struct passwd   *pw;
 223                 char            *username = cmd;        /* temp buffer */
 224
 225                 Debug(DPARS, ("load_entry()...about to parse username\n"))
 226                 ch = get_string(username, MAX_COMMAND, file, " \t");
 227
 228                 Debug(DPARS, ("load_entry()...got %s\n",username))
 229                 if (ch == EOF) {
 230                         ecode = e_cmd;
 231                         goto eof;
 232                 }
 233
 234                 pw = getpwnam(username);
 235                 if (pw == NULL) {
 236                         ecode = e_username;
 237                         goto eof;
 238                 }
 239                 Debug(DPARS, ("load_entry()...id %d\n",pw->pw_uid))
 240                 e->exec_uid = pw->pw_uid;
 241         }
 242
 243         Debug(DPARS, ("load_entry()...about to parse command\n"))
 244
 245         /* Everything up to the next \n or EOF is part of the command...
 246          * too bad we don't know in advance how long it will be, since we
 247          * need to malloc a string for it... so, we limit it to MAX_COMMAND
 248          */
 249         ch = get_string(cmd, MAX_COMMAND, file, "\n");
 250
 251         /* a file without a \n before the EOF is rude, so we'll complain...
 252          */
 253         if (ch == EOF) {
 254                 ecode = e_cmd;
 255                 goto eof;
 256         }
 257
 258         /* got the command in the 'cmd' string; save it in *e.
 259          */
 260         e->cmd = strdup(cmd);
 261
 262         Debug(DPARS, ("load_entry()...returning successfully\n"))
 263
 264         /* success, fini, return pointer to the entry we just created...
 265          */
 266         return e;
 267
 268 eof:    /* if we want to return EOF, we have to jump down here and
 269          * free the entry we've been building.
 270          *
 271          * now, in some cases, a parse routine will have returned EOF to
 272          * indicate an error, but the file is not actually done.  since, in
 273          * that case, we only want to skip the line with the error on it,
 274          * we'll do that here.
 275          *
 276          * many, including the author, see what's below as evil programming
 277          * practice: since I didn't want to change the structure of this
 278          * whole function to support this error recovery, I recurse.  Cursed!
 279          * (At least it's tail-recursion, as if it matters in C - vix/8feb88)
 280          * I'm seriously considering using (another) GOTO...   argh!
 281          * (this does not get less disgusting over time.  vix/15nov88)
 282          * (indeed not.  vix/20dec93)
 283          */
 284
 285         (void) free(e);
 286
 287         if (feof(file))
 288                 return NULL;
 289
 290         if (error_func)
 291                 (*error_func)(ecodes[(int)ecode]);
 292         do  {ch = get_char(file);}
 293         while (ch != EOF && ch != '\n');
 294         if (ch == EOF)
 295                 return NULL;
 296         return load_entry(file, error_func, 0);
 297 }
 298
 299
 300 static char
 301 get_list(bits, low, high, names, ch, file)
 302         bitstr_t        *bits;          /* one bit per flag, default=FALSE */
 303         int             low, high;      /* bounds, impl. offset for bitstr */
 304         char            *names[];       /* NULL or *[] of names for these elements */
 305         int             ch;             /* current character being processed */
 306         FILE            *file;          /* file being read */
 307 {
 308         register int    done;
 309
 310         /* we know that we point to a non-blank character here;
 311          * must do a Skip_Blanks before we exit, so that the
 312          * next call (or the code that picks up the cmd) can
 313          * assume the same thing.
 314          */
 315
 316         Debug(DPARS|DEXT, ("get_list()...entered\n"))
 317
 318         /* list = range {"," range}
 319          */
 320
 321         /* clear the bit string, since the default is 'off'.
 322          */
 323         bit_nclear(bits, 0, (high-low+1));
 324
 325         /* process all ranges
 326          */
 327         done = FALSE;
 328         while (!done) {
 329                 ch = get_range(bits, low, high, names, ch, file);
 330                 if (ch == ',')
 331                         ch = get_char(file);
 332                 else
 333                         done = TRUE;
 334         }
 335
 336         /* exiting.  skip to some blanks, then skip over the blanks.
 337          */
 338         Skip_Nonblanks(ch, file)
 339         Skip_Blanks(ch, file)
 340
 341         Debug(DPARS|DEXT, ("get_list()...exiting w/ %02x\n", ch))
 342
 343         return ch;
 344 }
 345
 346
 347 static char
 348 get_range(bits, low, high, names, ch, file)
 349         bitstr_t        *bits;          /* one bit per flag, default=FALSE */
 350         int             low, high;      /* bounds, impl. offset for bitstr */
 351         char            *names[];       /* NULL or names of elements */
 352         int             ch;             /* current character being processed */
 353         FILE            *file;          /* file being read */
 354 {
 355         /* range = number | number "-" number [ "/" number ]
 356          */
 357
 358         register int    i;
 359         auto int        num1, num2, num3;
 360
 361         Debug(DPARS|DEXT, ("get_range()...entering, exit won't show\n"))
 362
 363         if (ch == '*') {
 364                 /* '*' means "first-last" but can still be modified by /step
 365                  */
 366                 num1 = low;
 367                 num2 = high;
 368                 ch = get_char(file);
 369                 if (ch == EOF)
 370                         return EOF;
 371         } else {
 372                 if (EOF == (ch = get_number(&num1, low, names, ch, file)))
 373                         return EOF;
 374
 375                 if (ch != '-') {
 376                         /* not a range, it's a single number.
 377                          */
 378                         if (EOF == set_element(bits, low, high, num1))
 379                                 return EOF;
 380                         return ch;
 381                 } else {
 382                         /* eat the dash
 383                          */
 384                         ch = get_char(file);
 385                         if (ch == EOF)
 386                                 return EOF;
 387
 388                         /* get the number following the dash
 389                          */
 390                         ch = get_number(&num2, low, names, ch, file);
 391                         if (ch == EOF)
 392                                 return EOF;
 393                 }
 394         }
 395
 396         /* check for step size
 397          */
 398         if (ch == '/') {
 399                 /* eat the slash
 400                  */
 401                 ch = get_char(file);
 402                 if (ch == EOF)
 403                         return EOF;
 404
 405                 /* get the step size -- note: we don't pass the
 406                  * names here, because the number is not an
 407                  * element id, it's a step size.  'low' is
 408                  * sent as a 0 since there is no offset either.
 409                  */
 410                 ch = get_number(&num3, 0, PPC_NULL, ch, file);
 411                 if (ch == EOF)
 412                         return EOF;
 413         } else {
 414                 /* no step.  default==1.
 415                  */
 416                 num3 = 1;
 417         }
 418
 419         /* range. set all elements from num1 to num2, stepping
 420          * by num3.  (the step is a downward-compatible extension
 421          * proposed conceptually by bob@acornrc, syntactically
 422          * designed then implmented by paul vixie).
 423          */
 424         for (i = num1;  i <= num2;  i += num3)
 425                 if (EOF == set_element(bits, low, high, i))
 426                         return EOF;
 427
 428         return ch;
 429 }
 430
 431
 432 static char
 433 get_number(numptr, low, names, ch, file)
 434         int     *numptr;        /* where does the result go? */
 435         int     low;            /* offset applied to result if symbolic enum used */
 436         char    *names[];       /* symbolic names, if any, for enums */
 437         int     ch;             /* current character */
 438         FILE    *file;          /* source */
 439 {
 440         char    temp[MAX_TEMPSTR], *pc;
 441         int     len, i, all_digits;
 442
 443         /* collect alphanumerics into our fixed-size temp array
 444          */
 445         pc = temp;
 446         len = 0;
 447         all_digits = TRUE;
 448         while (isalnum(ch)) {
 449                 if (++len >= MAX_TEMPSTR)
 450                         return EOF;
 451
 452                 *pc++ = ch;
 453
 454                 if (!isdigit(ch))
 455                         all_digits = FALSE;
 456
 457                 ch = get_char(file);
 458         }
 459         *pc = '\0';
 460
 461         /* try to find the name in the name list
 462          */
 463         if (names) {
 464                 for (i = 0;  names[i] != NULL;  i++) {
 465                         Debug(DPARS|DEXT,
 466                                 ("get_num, compare(%s,%s)\n", names[i], temp))
 467                         if (!strcasecmp(names[i], temp)) {
 468                                 *numptr = i+low;
 469                                 return ch;
 470                         }
 471                 }
 472         }
 473
 474         /* no name list specified, or there is one and our string isn't
 475          * in it.  either way: if it's all digits, use its magnitude.
 476          * otherwise, it's an error.
 477          */
 478         if (all_digits) {
 479                 *numptr = atoi(temp);
 480                 return ch;
 481         }
 482
 483         return EOF;
 484 }
 485
 486
 487 static int
 488 set_element(bits, low, high, number)
 489         bitstr_t        *bits;          /* one bit per flag, default=FALSE */
 490         int             low;
 491         int             high;
 492         int             number;
 493 {
 494         Debug(DPARS|DEXT, ("set_element(?,%d,%d,%d)\n", low, high, number))
 495
 496         if (number < low || number > high)
 497                 return EOF;
 498
 499         bit_set(bits, (number-low));
 500         return OK;
 501 }