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[netbsd-mini2440.git] / libexec / cron / entry.c

/* Copyright 1988,1990,1993 by Paul Vixie
 * All rights reserved
 *
 * Distribute freely, except: don't remove my name from the source or
 * documentation (don't take credit for my work), mark your changes (don't
 * get me blamed for your possible bugs), don't alter or remove this
 * notice.  May be sold if buildable source is provided to buyer.  No
 * warrantee of any kind, express or implied, is included with this
 * software; use at your own risk, responsibility for damages (if any) to
 * anyone resulting from the use of this software rests entirely with the
 * user.
 *
 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
 * I'll try to keep a version up to date.  I can be reached as follows:
 * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
 */

#if !defined(lint) && !defined(LINT)
static char rcsid[] = "$Id: entry.c,v 1.1 1994/01/05 20:40:14 jtc Exp $";
#endif

/* vix 26jan87 [RCS'd; rest of log is in RCS file]
 * vix 01jan87 [added line-level error recovery]
 * vix 31dec86 [added /step to the from-to range, per bob@acornrc]
 * vix 30dec86 [written]
 */


#include "cron.h"
#include "externs.h"
#include <pwd.h>


typedef enum ecode {
        e_none, e_minute, e_hour, e_dom, e_month, e_dow,
        e_cmd, e_timespec, e_username
} ecode_e;

static char     get_list __P((bitstr_t *, int, int, char *[], int, FILE *)),
                get_range __P((bitstr_t *, int, int, char *[], int, FILE *)),
                get_number __P((int *, int, char *[], int, FILE *));
static int      set_element __P((bitstr_t *, int, int, int));

static char *ecodes[] =
        {
                "no error",
                "bad minute",
                "bad hour",
                "bad day-of-month",
                "bad month",
                "bad day-of-week",
                "bad command",
                "bad time specifier",
                "bad username",
        };


void
free_entry(e)
        entry   *e;
{
        free(e->cmd);
        free(e);
}


entry *
load_entry(file, error_func, syscron)
        FILE    *file;
        void    (*error_func)();
        int     syscron;
{
        /* this function reads one crontab entry -- the next -- from a file.
         * it skips any leading blank lines, ignores comments, and returns
         * EOF if for any reason the entry can't be read and parsed.
         *
         * the entry is also parsed here.
         *
         * syntax:
         *   user crontab:
         *      minutes hours doms months dows cmd\n
         *   system crontab (/etc/crontab):
         *      minutes hours doms months dows USERNAME cmd\n
         */

        ecode_e ecode = e_none;
        entry   *e;
        int     ch;
        char    cmd[MAX_COMMAND];

        e = (entry *) calloc(sizeof(entry), sizeof(char));

        Debug(DPARS, ("load_entry()...about to eat comments\n"))

        skip_comments(file);

        ch = get_char(file);
        if (ch == EOF)
                return NULL;

        /* ch is now the first useful character of a useful line.
         * it may be an @special or it may be the first character
         * of a list of minutes.
         */

        if (ch == '@') {
                /* all of these should be flagged and load-limited; i.e.,
                 * instead of @hourly meaning "0 * * * *" it should mean
                 * "close to the front of every hour but not 'til the
                 * system load is low".  Problems are: how do you know
                 * what "low" means? (save me from /etc/cron.conf!) and:
                 * how to guarantee low variance (how low is low?), which
                 * means how to we run roughly every hour -- seems like
                 * we need to keep a history or let the first hour set
                 * the schedule, which means we aren't load-limited
                 * anymore.  too much for my overloaded brain. (vix, jan90)
                 * HINT
                 */
                ch = get_string(cmd, MAX_COMMAND, file, " \t\n");
                if (!strcmp("reboot", cmd)) {
                        e->flags |= WHEN_REBOOT;
                } else if (!strcmp("yearly", cmd) || !strcmp("annually", cmd)){
                        bit_set(e->minute, 0);
                        bit_set(e->hour, 0);
                        bit_set(e->dom, 0);
                        bit_set(e->month, 0);
                        bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
                } else if (!strcmp("monthly", cmd)) {
                        bit_set(e->minute, 0);
                        bit_set(e->hour, 0);
                        bit_set(e->dom, 0);
                        bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
                        bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
                } else if (!strcmp("weekly", cmd)) {
                        bit_set(e->minute, 0);
                        bit_set(e->hour, 0);
                        bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
                        bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
                        bit_set(e->dow, 0);
                } else if (!strcmp("daily", cmd) || !strcmp("midnight", cmd)) {
                        bit_set(e->minute, 0);
                        bit_set(e->hour, 0);
                        bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
                        bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
                        bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
                } else if (!strcmp("hourly", cmd)) {
                        bit_set(e->minute, 0);
                        bit_set(e->hour, (LAST_HOUR-FIRST_HOUR+1));
                        bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
                        bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
                        bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
                } else {
                        ecode = e_timespec;
                        goto eof;
                }
        } else {
                Debug(DPARS, ("load_entry()...about to parse numerics\n"))

                ch = get_list(e->minute, FIRST_MINUTE, LAST_MINUTE,
                              PPC_NULL, ch, file);
                if (ch == EOF) {
                        ecode = e_minute;
                        goto eof;
                }

                /* hours
                 */

                ch = get_list(e->hour, FIRST_HOUR, LAST_HOUR,
                              PPC_NULL, ch, file);
                if (ch == EOF) {
                        ecode = e_hour;
                        goto eof;
                }

                /* DOM (days of month)
                 */

                if (ch == '*')
                        e->flags |= DOM_STAR;
                ch = get_list(e->dom, FIRST_DOM, LAST_DOM,
                              PPC_NULL, ch, file);
                if (ch == EOF) {
                        ecode = e_dom;
                        goto eof;
                }

                /* month
                 */

                ch = get_list(e->month, FIRST_MONTH, LAST_MONTH,
                              MonthNames, ch, file);
                if (ch == EOF) {
                        ecode = e_month;
                        goto eof;
                }

                /* DOW (days of week)
                 */

                if (ch == '*')
                        e->flags |= DOW_STAR;
                ch = get_list(e->dow, FIRST_DOW, LAST_DOW,
                              DowNames, ch, file);
                if (ch == EOF) {
                        ecode = e_dow;
                        goto eof;
                }
        }

        /* make sundays equivilent */
        if (bit_test(e->dow, 0) || bit_test(e->dow, 7)) {
                bit_set(e->dow, 0);
                bit_set(e->dow, 7);
        }

        /* ch is the first character of a command, or a username */
        unget_char(ch, file);

        e->exec_uid = 0;                /* default to user */
        if (syscron) {
                struct passwd   *pw;
                char            *username = cmd;        /* temp buffer */

                Debug(DPARS, ("load_entry()...about to parse username\n"))
                ch = get_string(username, MAX_COMMAND, file, " \t");

                Debug(DPARS, ("load_entry()...got %s\n",username))
                if (ch == EOF) {
                        ecode = e_cmd;
                        goto eof;
                }

                pw = getpwnam(username);
                if (pw == NULL) {
                        ecode = e_username;
                        goto eof;
                }
                Debug(DPARS, ("load_entry()...id %d\n",pw->pw_uid))
                e->exec_uid = pw->pw_uid;
        }

        Debug(DPARS, ("load_entry()...about to parse command\n"))

        /* Everything up to the next \n or EOF is part of the command...
         * too bad we don't know in advance how long it will be, since we
         * need to malloc a string for it... so, we limit it to MAX_COMMAND
         */ 
        ch = get_string(cmd, MAX_COMMAND, file, "\n");

        /* a file without a \n before the EOF is rude, so we'll complain...
         */
        if (ch == EOF) {
                ecode = e_cmd;
                goto eof;
        }

        /* got the command in the 'cmd' string; save it in *e.
         */
        e->cmd = strdup(cmd);

        Debug(DPARS, ("load_entry()...returning successfully\n"))

        /* success, fini, return pointer to the entry we just created...
         */
        return e;

eof:    /* if we want to return EOF, we have to jump down here and
         * free the entry we've been building.
         *
         * now, in some cases, a parse routine will have returned EOF to
         * indicate an error, but the file is not actually done.  since, in
         * that case, we only want to skip the line with the error on it,
         * we'll do that here.
         *
         * many, including the author, see what's below as evil programming
         * practice: since I didn't want to change the structure of this
         * whole function to support this error recovery, I recurse.  Cursed!
         * (At least it's tail-recursion, as if it matters in C - vix/8feb88)
         * I'm seriously considering using (another) GOTO...   argh!
         * (this does not get less disgusting over time.  vix/15nov88)
         * (indeed not.  vix/20dec93)
         */

        (void) free(e);

        if (feof(file))
                return NULL;

        if (error_func)
                (*error_func)(ecodes[(int)ecode]);
        do  {ch = get_char(file);}
        while (ch != EOF && ch != '\n');
        if (ch == EOF)
                return NULL;
        return load_entry(file, error_func, 0);
}


static char
get_list(bits, low, high, names, ch, file)
        bitstr_t        *bits;          /* one bit per flag, default=FALSE */
        int             low, high;      /* bounds, impl. offset for bitstr */
        char            *names[];       /* NULL or *[] of names for these elements */
        int             ch;             /* current character being processed */
        FILE            *file;          /* file being read */
{
        register int    done;

        /* we know that we point to a non-blank character here;
         * must do a Skip_Blanks before we exit, so that the
         * next call (or the code that picks up the cmd) can
         * assume the same thing.
         */

        Debug(DPARS|DEXT, ("get_list()...entered\n"))

        /* list = range {"," range}
         */
        
        /* clear the bit string, since the default is 'off'.
         */
        bit_nclear(bits, 0, (high-low+1));

        /* process all ranges
         */
        done = FALSE;
        while (!done) {
                ch = get_range(bits, low, high, names, ch, file);
                if (ch == ',')
                        ch = get_char(file);
                else
                        done = TRUE;
        }

        /* exiting.  skip to some blanks, then skip over the blanks.
         */
        Skip_Nonblanks(ch, file)
        Skip_Blanks(ch, file)

        Debug(DPARS|DEXT, ("get_list()...exiting w/ %02x\n", ch))

        return ch;
}


static char
get_range(bits, low, high, names, ch, file)
        bitstr_t        *bits;          /* one bit per flag, default=FALSE */
        int             low, high;      /* bounds, impl. offset for bitstr */
        char            *names[];       /* NULL or names of elements */
        int             ch;             /* current character being processed */
        FILE            *file;          /* file being read */
{
        /* range = number | number "-" number [ "/" number ]
         */

        register int    i;
        auto int        num1, num2, num3;

        Debug(DPARS|DEXT, ("get_range()...entering, exit won't show\n"))

        if (ch == '*') {
                /* '*' means "first-last" but can still be modified by /step
                 */
                num1 = low;
                num2 = high;
                ch = get_char(file);
                if (ch == EOF)
                        return EOF;
        } else {
                if (EOF == (ch = get_number(&num1, low, names, ch, file)))
                        return EOF;

                if (ch != '-') {
                        /* not a range, it's a single number.
                         */
                        if (EOF == set_element(bits, low, high, num1))
                                return EOF;
                        return ch;
                } else {
                        /* eat the dash
                         */
                        ch = get_char(file);
                        if (ch == EOF)
                                return EOF;

                        /* get the number following the dash
                         */
                        ch = get_number(&num2, low, names, ch, file);
                        if (ch == EOF)
                                return EOF;
                }
        }

        /* check for step size
         */
        if (ch == '/') {
                /* eat the slash
                 */
                ch = get_char(file);
                if (ch == EOF)
                        return EOF;

                /* get the step size -- note: we don't pass the
                 * names here, because the number is not an
                 * element id, it's a step size.  'low' is
                 * sent as a 0 since there is no offset either.
                 */
                ch = get_number(&num3, 0, PPC_NULL, ch, file);
                if (ch == EOF)
                        return EOF;
        } else {
                /* no step.  default==1.
                 */
                num3 = 1;
        }

        /* range. set all elements from num1 to num2, stepping
         * by num3.  (the step is a downward-compatible extension
         * proposed conceptually by bob@acornrc, syntactically
         * designed then implmented by paul vixie).
         */
        for (i = num1;  i <= num2;  i += num3)
                if (EOF == set_element(bits, low, high, i))
                        return EOF;

        return ch;
}


static char
get_number(numptr, low, names, ch, file)
        int     *numptr;        /* where does the result go? */
        int     low;            /* offset applied to result if symbolic enum used */
        char    *names[];       /* symbolic names, if any, for enums */
        int     ch;             /* current character */
        FILE    *file;          /* source */
{
        char    temp[MAX_TEMPSTR], *pc;
        int     len, i, all_digits;

        /* collect alphanumerics into our fixed-size temp array
         */
        pc = temp;
        len = 0;
        all_digits = TRUE;
        while (isalnum(ch)) {
                if (++len >= MAX_TEMPSTR)
                        return EOF;

                *pc++ = ch;

                if (!isdigit(ch))
                        all_digits = FALSE;

                ch = get_char(file);
        }
        *pc = '\0';

        /* try to find the name in the name list
         */
        if (names) {
                for (i = 0;  names[i] != NULL;  i++) {
                        Debug(DPARS|DEXT,
                                ("get_num, compare(%s,%s)\n", names[i], temp))
                        if (!strcasecmp(names[i], temp)) {
                                *numptr = i+low;
                                return ch;
                        }
                }
        }

        /* no name list specified, or there is one and our string isn't
         * in it.  either way: if it's all digits, use its magnitude.
         * otherwise, it's an error.
         */
        if (all_digits) {
                *numptr = atoi(temp);
                return ch;
        }

        return EOF;
}


static int
set_element(bits, low, high, number)
        bitstr_t        *bits;          /* one bit per flag, default=FALSE */
        int             low;
        int             high;
        int             number;
{
        Debug(DPARS|DEXT, ("set_element(?,%d,%d,%d)\n", low, high, number))

        if (number < low || number > high)
                return EOF;

        bit_set(bits, (number-low));
        return OK;
}