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NetBSD/usr.sbin/cron/entry.c

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/* $NetBSD: entry.c,v 1.9 2008/02/16 07:26:00 matt Exp $ */
/* Copyright 1988,1990,1993,1994 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
*/
#include <sys/cdefs.h>
#if !defined(lint) && !defined(LINT)
#if 0
static char rcsid[] = "Id: entry.c,v 2.12 1994/01/17 03:20:37 vixie Exp";
#else
__RCSID("$NetBSD: entry.c,v 1.9 2008/02/16 07:26:00 matt Exp $");
#endif
#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"
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(bitstr_t *, int, int, const char * const [], int, FILE *),
get_range(bitstr_t *, int, int, const char * const [], int, FILE *),
get_number(int *, int, const char * const [], int, FILE *);
static int set_element(bitstr_t *, int, int, int);
static const char * const 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(entry *e)
{
free(e->cmd);
env_free(e->envp);
free(e);
}
/* return NULL if eof or syntax error occurs;
* otherwise return a pointer to a new entry.
*/
entry *
load_entry(FILE *file, void (*error_func)(const char *), struct passwd *pw,
char **envp)
{
/* 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];
char envstr[MAX_ENVSTR];
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.
*/
e = (entry *) calloc(sizeof(entry), sizeof(char));
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));
e->flags |= DOW_STAR;
} 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));
e->flags |= DOW_STAR;
} 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);
e->flags |= DOM_STAR;
} 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));
e->flags |= DOM_STAR | DOW_STAR;
} else if (!strcmp("hourly", cmd)) {
bit_set(e->minute, 0);
bit_nset(e->hour, 0, (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));
e->flags |= DOM_STAR | DOW_STAR;
} 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);
if (!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()...uid %d, gid %d\n",e->uid,e->gid))
}
e->uid = pw->pw_uid;
e->gid = pw->pw_gid;
/* copy and fix up environment. some variables are just defaults and
* others are overrides.
*/
e->envp = env_copy(envp);
if (!env_get("SHELL", e->envp)) {
snprintf(envstr, sizeof(envstr), "SHELL=%s", _PATH_BSHELL);
e->envp = env_set(e->envp, envstr);
}
if (!env_get("HOME", e->envp)) {
snprintf(envstr, sizeof(envstr), "HOME=%s", pw->pw_dir);
e->envp = env_set(e->envp, envstr);
}
if (!env_get("PATH", e->envp)) {
snprintf(envstr, sizeof(envstr), "PATH=%s", _PATH_DEFPATH);
e->envp = env_set(e->envp, envstr);
}
snprintf(envstr, sizeof(envstr), "%s=%s", "LOGNAME", pw->pw_name);
e->envp = env_set(e->envp, envstr);
#if defined(BSD)
snprintf(envstr, sizeof(envstr), "%s=%s", "USER", pw->pw_name);
e->envp = env_set(e->envp, envstr);
#endif
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.
* XXX - should use realloc().
*/
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:
free(e);
if (ecode != e_none && error_func)
(*error_func)(ecodes[(int)ecode]);
while (ch != EOF && ch != '\n')
ch = get_char(file);
return NULL;
}
static char
get_list(bitstr_t *bits, /* one bit per flag, default=FALSE */
int low, /* bounds, impl. offset for bitstr */
int high, /* bounds, impl. offset for bitstr */
const char * const names[], /* NULL or *[] of names for these elements */
int ch, /* current character being processed */
FILE *file /* file being read */)
{
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(bitstr_t *bits, /* one bit per flag, default=FALSE */
int low, /* bounds, impl. offset for bitstr */
int high, /* bounds, impl. offset for bitstr */
const char * const names[], /* NULL or names of elements */
int ch, /* current character being processed */
FILE *file /* file being read */)
{
/* range = number | number "-" number [ "/" number ]
*/
int i;
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(int *numptr, /* where does the result go? */
int low, /* offset applied to result if symbolic enum used */
const char * const 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(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;
}
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