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/* $OpenBSD: database.c,v 1.31 2015/11/09 16:37:07 millert Exp $ */
/* Copyright 1988,1990,1993,1994 by Paul Vixie
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <bitstring.h> /* for structs.h */
#include <dirent.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h> /* for structs.h */
#include <unistd.h>
#include "pathnames.h"
#include "macros.h"
#include "structs.h"
#include "funcs.h"
#define HASH(a,b) ((a)+(b))
static void process_crontab(const char *, const char *,
const char *, struct stat *,
cron_db *, cron_db *);
void
load_database(cron_db **db)
{
struct stat statbuf, syscron_stat;
cron_db *new_db, *old_db = *db;
struct dirent *dp;
DIR *dir;
user *u;
/* before we start loading any data, do a stat on CRON_SPOOL
* so that if anything changes as of this moment (i.e., before we've
* cached any of the database), we'll see the changes next time.
*/
if (stat(CRON_SPOOL, &statbuf) < 0) {
log_it("CRON", "STAT FAILED", CRON_SPOOL);
return;
}
/* track system crontab file
*/
if (stat(SYSCRONTAB, &syscron_stat) < 0)
syscron_stat.st_mtime = 0;
/* if spooldir's mtime has not changed, we don't need to fiddle with
* the database.
*/
if (old_db != NULL &&
old_db->mtime == HASH(statbuf.st_mtime, syscron_stat.st_mtime)) {
return;
}
/* something's different. make a new database, moving unchanged
* elements from the old database, reloading elements that have
* actually changed. Whatever is left in the old database when
* we're done is chaff -- crontabs that disappeared.
*/
if ((new_db = malloc(sizeof(*new_db))) == NULL)
return;
new_db->mtime = HASH(statbuf.st_mtime, syscron_stat.st_mtime);
TAILQ_INIT(&new_db->users);
if (syscron_stat.st_mtime) {
process_crontab("root", NULL, SYSCRONTAB, &syscron_stat,
new_db, old_db);
}
/* we used to keep this dir open all the time, for the sake of
* efficiency. however, we need to close it in every fork, and
* we fork a lot more often than the mtime of the dir changes.
*/
if (!(dir = opendir(CRON_SPOOL))) {
log_it("CRON", "OPENDIR FAILED", CRON_SPOOL);
/* Restore system crontab entry as needed. */
if (!TAILQ_EMPTY(&new_db->users) &&
(u = TAILQ_FIRST(&old_db->users))) {
if (strcmp(u->name, "*system*") == 0) {
TAILQ_REMOVE(&old_db->users, u, entries);
free_user(u);
TAILQ_INSERT_HEAD(&old_db->users,
TAILQ_FIRST(&new_db->users), entries);
}
}
free(new_db);
return;
}
while (NULL != (dp = readdir(dir))) {
char fname[NAME_MAX+1], tabname[MAX_FNAME];
/* avoid file names beginning with ".". this is good
* because we would otherwise waste two guaranteed calls
* to getpwnam() for . and .., and also because user names
* starting with a period are just too nasty to consider.
*/
if (dp->d_name[0] == '.')
continue;
if (strlcpy(fname, dp->d_name, sizeof fname) >= sizeof fname)
continue; /* XXX log? */
if (snprintf(tabname, sizeof tabname, "%s/%s", CRON_SPOOL, fname) >=
sizeof(tabname))
continue; /* XXX log? */
process_crontab(fname, fname, tabname,
&statbuf, new_db, old_db);
}
closedir(dir);
/* if we don't do this, then when our children eventually call
* getpwnam() in do_command.c's child_process to verify MAILTO=,
* they will screw us up (and v-v).
*/
endpwent();
/* whatever's left in the old database is now junk.
*/
if (old_db != NULL) {
while ((u = TAILQ_FIRST(&old_db->users))) {
TAILQ_REMOVE(&old_db->users, u, entries);
free_user(u);
}
free(old_db);
}
/* overwrite the database control block with the new one.
*/
*db = new_db;
}
user *
find_user(cron_db *db, const char *name)
{
user *u = NULL;
if (db != NULL) {
TAILQ_FOREACH(u, &db->users, entries) {
if (strcmp(u->name, name) == 0)
break;
}
}
return (u);
}
static void
process_crontab(const char *uname, const char *fname, const char *tabname,
struct stat *statbuf, cron_db *new_db, cron_db *old_db)
{
struct passwd *pw = NULL;
int crontab_fd = -1;
user *u;
if (fname == NULL) {
/* must be set to something for logging purposes.
*/
fname = "*system*";
} else if ((pw = getpwnam(uname)) == NULL) {
/* file doesn't have a user in passwd file.
*/
log_it(fname, "ORPHAN", "no passwd entry");
goto next_crontab;
}
if ((crontab_fd = open(tabname, O_RDONLY|O_NONBLOCK|O_NOFOLLOW, 0)) < 0) {
/* crontab not accessible?
*/
log_it(fname, "CAN'T OPEN", tabname);
goto next_crontab;
}
if (fstat(crontab_fd, statbuf) < 0) {
log_it(fname, "FSTAT FAILED", tabname);
goto next_crontab;
}
if (!S_ISREG(statbuf->st_mode)) {
log_it(fname, "NOT REGULAR", tabname);
goto next_crontab;
}
if ((statbuf->st_mode & 07577) != 0400) {
/* Looser permissions on system crontab. */
if (pw != NULL || (statbuf->st_mode & 022) != 0) {
log_it(fname, "BAD FILE MODE", tabname);
goto next_crontab;
}
}
if (statbuf->st_uid != 0 && (pw == NULL ||
statbuf->st_uid != pw->pw_uid || strcmp(uname, pw->pw_name) != 0)) {
log_it(fname, "WRONG FILE OWNER", tabname);
goto next_crontab;
}
if (pw != NULL && statbuf->st_nlink != 1) {
log_it(fname, "BAD LINK COUNT", tabname);
goto next_crontab;
}
u = find_user(old_db, fname);
if (u != NULL) {
/* if crontab has not changed since we last read it
* in, then we can just use our existing entry.
*/
if (u->mtime == statbuf->st_mtime) {
TAILQ_REMOVE(&old_db->users, u, entries);
TAILQ_INSERT_TAIL(&new_db->users, u, entries);
goto next_crontab;
}
/* before we fall through to the code that will reload
* the user, let's deallocate and unlink the user in
* the old database. This is more a point of memory
* efficiency than anything else, since all leftover
* users will be deleted from the old database when
* we finish with the crontab...
*/
TAILQ_REMOVE(&old_db->users, u, entries);
free_user(u);
log_it(fname, "RELOAD", tabname);
}
u = load_user(crontab_fd, pw, fname);
if (u != NULL) {
u->mtime = statbuf->st_mtime;
TAILQ_INSERT_TAIL(&new_db->users, u, entries);
}
next_crontab:
if (crontab_fd >= 0) {
close(crontab_fd);
}
}
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