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freebsd-skq/usr.sbin/cron/lib/entry.c
Oleksandr Tymoshenko 37cd6c20db cron: consume blanks in system crontabs before options 
On system crontabs, multiple blanks are not being consumed after reading the
username. This change adds blank consumption before parsing any -[qn] options.
Without this change, an entry like:

  * * * * * username  -n true  # Two spaces between username and option.

will fail, as the shell will try to execute (' -n true'), while an entry like:

  * * * * * username -n true   # One space between username and option.

works as expected (executes 'true').

For user crontabs, this is not an issue as the preceding (day of week
or @shortcut) processing consumes any leading whitespace.

PR:		253699
Submitted by:	Eric A. Borisch <eborisch@gmail.com>
MFC after:	1 week
2021-03-03 23:23:31 -08:00

725 lines
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/* 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
*/
#if !defined(lint) && !defined(LINT)
static const char rcsid[] =
"$FreeBSD$";
#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 <grp.h>
#ifdef LOGIN_CAP
#include <login_cap.h>
#endif
typedef enum ecode {
e_none, e_minute, e_hour, e_dom, e_month, e_dow,
e_cmd, e_timespec, e_username, e_group, e_option,
e_mem
#ifdef LOGIN_CAP
, e_class
#endif
} ecode_e;
static char get_list(bitstr_t *, int, int, char *[], int, FILE *),
get_range(bitstr_t *, int, int, char *[], int, FILE *),
get_number(int *, int, char *[], int, FILE *);
static int set_element(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",
"bad group name",
"bad option",
"out of memory",
#ifdef LOGIN_CAP
"bad class name",
#endif
};
void
free_entry(e)
entry *e;
{
#ifdef LOGIN_CAP
if (e->class != NULL)
free(e->class);
#endif
if (e->cmd != NULL)
free(e->cmd);
if (e->envp != NULL)
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, error_func, pw, envp)
FILE *file;
void (*error_func)(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];
char **prev_env;
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 (e == NULL) {
warn("load_entry: calloc failed");
return NULL;
}
if (ch == '@') {
long interval;
char *endptr;
/* 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
*/
Debug(DPARS, ("load_entry()...about to test shortcuts\n"))
ch = get_string(cmd, MAX_COMMAND, file, " \t\n");
if (!strcmp("reboot", cmd)) {
Debug(DPARS, ("load_entry()...reboot shortcut\n"))
e->flags |= WHEN_REBOOT;
} else if (!strcmp("yearly", cmd) || !strcmp("annually", cmd)){
Debug(DPARS, ("load_entry()...yearly shortcut\n"))
bit_set(e->second, 0);
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)) {
Debug(DPARS, ("load_entry()...monthly shortcut\n"))
bit_set(e->second, 0);
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)) {
Debug(DPARS, ("load_entry()...weekly shortcut\n"))
bit_set(e->second, 0);
bit_set(e->minute, 0);
bit_set(e->hour, 0);
bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
e->flags |= DOM_STAR;
bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
bit_set(e->dow, 0);
} else if (!strcmp("daily", cmd) || !strcmp("midnight", cmd)) {
Debug(DPARS, ("load_entry()...daily shortcut\n"))
bit_set(e->second, 0);
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)) {
Debug(DPARS, ("load_entry()...hourly shortcut\n"))
bit_set(e->second, 0);
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));
} else if (!strcmp("every_minute", cmd)) {
Debug(DPARS, ("load_entry()...every_minute shortcut\n"))
bit_set(e->second, 0);
bit_nset(e->minute, 0, (LAST_MINUTE-FIRST_MINUTE+1));
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));
} else if (!strcmp("every_second", cmd)) {
Debug(DPARS, ("load_entry()...every_second shortcut\n"))
e->flags |= SEC_RES;
bit_nset(e->second, 0, (LAST_SECOND-FIRST_SECOND+1));
bit_nset(e->minute, 0, (LAST_MINUTE-FIRST_MINUTE+1));
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));
} else if (*cmd != '\0' &&
(interval = strtol(cmd, &endptr, 10)) > 0 &&
*endptr == '\0') {
Debug(DPARS, ("load_entry()... %ld seconds "
"since last run\n", interval))
e->interval = interval;
e->flags = INTERVAL;
} else {
ecode = e_timespec;
goto eof;
}
/* Advance past whitespace between shortcut and
* username/command.
*/
Skip_Blanks(ch, file);
if (ch == EOF) {
ecode = e_cmd;
goto eof;
}
} else {
Debug(DPARS, ("load_entry()...about to parse numerics\n"))
bit_set(e->second, 0);
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 equivalent */
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 */
char *s;
struct group *grp;
#ifdef LOGIN_CAP
login_cap_t *lc;
#endif
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;
}
/* need to have consumed blanks when checking options below */
Skip_Blanks(ch, file)
unget_char(ch, file);
#ifdef LOGIN_CAP
if ((s = strrchr(username, '/')) != NULL) {
*s = '\0';
e->class = strdup(s + 1);
if (e->class == NULL)
warn("strdup(\"%s\")", s + 1);
} else {
e->class = strdup(RESOURCE_RC);
if (e->class == NULL)
warn("strdup(\"%s\")", RESOURCE_RC);
}
if (e->class == NULL) {
ecode = e_mem;
goto eof;
}
if ((lc = login_getclass(e->class)) == NULL) {
ecode = e_class;
goto eof;
}
login_close(lc);
#endif
grp = NULL;
if ((s = strrchr(username, ':')) != NULL) {
*s = '\0';
if ((grp = getgrnam(s + 1)) == NULL) {
ecode = e_group;
goto eof;
}
}
pw = getpwnam(username);
if (pw == NULL) {
ecode = e_username;
goto eof;
}
if (grp != NULL)
pw->pw_gid = grp->gr_gid;
Debug(DPARS, ("load_entry()...uid %d, gid %d\n",pw->pw_uid,pw->pw_gid))
#ifdef LOGIN_CAP
Debug(DPARS, ("load_entry()...class %s\n",e->class))
#endif
}
#ifndef PAM /* PAM takes care of account expiration by itself */
if (pw->pw_expire && time(NULL) >= pw->pw_expire) {
ecode = e_username;
goto eof;
}
#endif /* !PAM */
e->uid = pw->pw_uid;
e->gid = pw->pw_gid;
/* copy and fix up environment. some variables are just defaults and
* others are overrides; we process only the overrides here, defaults
* are handled in do_command after login.conf is processed.
*/
e->envp = env_copy(envp);
if (e->envp == NULL) {
warn("env_copy");
ecode = e_mem;
goto eof;
}
if (!env_get("SHELL", e->envp)) {
prev_env = e->envp;
sprintf(envstr, "SHELL=%s", _PATH_BSHELL);
e->envp = env_set(e->envp, envstr);
if (e->envp == NULL) {
warn("env_set(%s)", envstr);
env_free(prev_env);
ecode = e_mem;
goto eof;
}
}
/* If LOGIN_CAP, this is deferred to do_command where the login class
* is processed. If !LOGIN_CAP, do it here.
*/
#ifndef LOGIN_CAP
if (!env_get("HOME", e->envp)) {
prev_env = e->envp;
sprintf(envstr, "HOME=%s", pw->pw_dir);
e->envp = env_set(e->envp, envstr);
if (e->envp == NULL) {
warn("env_set(%s)", envstr);
env_free(prev_env);
ecode = e_mem;
goto eof;
}
}
#endif
prev_env = e->envp;
sprintf(envstr, "%s=%s", "LOGNAME", pw->pw_name);
e->envp = env_set(e->envp, envstr);
if (e->envp == NULL) {
warn("env_set(%s)", envstr);
env_free(prev_env);
ecode = e_mem;
goto eof;
}
#if defined(BSD)
prev_env = e->envp;
sprintf(envstr, "%s=%s", "USER", pw->pw_name);
e->envp = env_set(e->envp, envstr);
if (e->envp == NULL) {
warn("env_set(%s)", envstr);
env_free(prev_env);
ecode = e_mem;
goto eof;
}
#endif
Debug(DPARS, ("load_entry()...checking for command options\n"))
ch = get_char(file);
while (ch == '-') {
Debug(DPARS|DEXT, ("load_entry()...expecting option\n"))
switch (ch = get_char(file)) {
case 'n':
Debug(DPARS|DEXT, ("load_entry()...got MAIL_WHEN_ERR ('n') option\n"))
/* only allow the user to set the option once */
if ((e->flags & MAIL_WHEN_ERR) == MAIL_WHEN_ERR) {
Debug(DPARS|DEXT, ("load_entry()...duplicate MAIL_WHEN_ERR ('n') option\n"))
ecode = e_option;
goto eof;
}
e->flags |= MAIL_WHEN_ERR;
break;
case 'q':
Debug(DPARS|DEXT, ("load_entry()...got DONT_LOG ('q') option\n"))
/* only allow the user to set the option once */
if ((e->flags & DONT_LOG) == DONT_LOG) {
Debug(DPARS|DEXT, ("load_entry()...duplicate DONT_LOG ('q') option\n"))
ecode = e_option;
goto eof;
}
e->flags |= DONT_LOG;
break;
default:
Debug(DPARS|DEXT, ("load_entry()...invalid option '%c'\n", ch))
ecode = e_option;
goto eof;
}
ch = get_char(file);
if (ch!='\t' && ch!=' ') {
ecode = e_option;
goto eof;
}
Skip_Blanks(ch, file)
if (ch == EOF || ch == '\n') {
ecode = e_cmd;
goto eof;
}
}
unget_char(ch, file);
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);
if (e->cmd == NULL) {
warn("strdup(\"%s\")", cmd);
ecode = e_mem;
goto eof;
}
Debug(DPARS, ("load_entry()...returning successfully\n"))
/* success, fini, return pointer to the entry we just created...
*/
return e;
eof:
free_entry(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(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 == '/')
num2 = high;
else 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 || num3 == 0)
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';
if (len == 0)
return (EOF);
/* 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;
}
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