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/* $OpenBSD: database.c,v 1.25 2015/02/09 22:35:08 deraadt 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.
*/
/* vix 26jan87 [RCS has the log]
*/
#include "cron.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 *old_db)
{
struct stat statbuf, syscron_stat;
cron_db new_db;
struct dirent *dp;
DIR *dir;
user *u, *nu;
/* before we start loading any data, do a stat on SPOOL_DIR
* 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(SPOOL_DIR, &statbuf) < 0) {
log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR);
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.
*
* Note that old_db->mtime is initialized to 0 in main(), and
* so is guaranteed to be different than the stat() mtime the first
* time this function is called.
*/
if (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.
*/
new_db.mtime = HASH(statbuf.st_mtime, syscron_stat.st_mtime);
new_db.head = new_db.tail = NULL;
if (syscron_stat.st_mtime) {
process_crontab(ROOT_USER, 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(SPOOL_DIR))) {
log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR);
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", SPOOL_DIR, 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.
*/
for (u = old_db->head; u != NULL; u = nu) {
nu = u->next;
unlink_user(old_db, u);
free_user(u);
}
/* overwrite the database control block with the new one.
*/
*old_db = new_db;
}
void
link_user(cron_db *db, user *u)
{
if (db->head == NULL)
db->head = u;
if (db->tail)
db->tail->next = u;
u->prev = db->tail;
u->next = NULL;
db->tail = u;
}
void
unlink_user(cron_db *db, user *u)
{
if (u->prev == NULL)
db->head = u->next;
else
u->prev->next = u->next;
if (u->next == NULL)
db->tail = u->prev;
else
u->next->prev = u->prev;
}
user *
find_user(cron_db *db, const char *name)
{
user *u;
for (u = db->head; u != NULL; u = u->next)
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, getpid(), "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, getpid(), "CAN'T OPEN", tabname);
goto next_crontab;
}
if (fstat(crontab_fd, statbuf) < 0) {
log_it(fname, getpid(), "FSTAT FAILED", tabname);
goto next_crontab;
}
if (!S_ISREG(statbuf->st_mode)) {
log_it(fname, getpid(), "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, getpid(), "BAD FILE MODE", tabname);
goto next_crontab;
}
}
if (statbuf->st_uid != ROOT_UID && (pw == NULL ||
statbuf->st_uid != pw->pw_uid || strcmp(uname, pw->pw_name) != 0)) {
log_it(fname, getpid(), "WRONG FILE OWNER", tabname);
goto next_crontab;
}
if (pw != NULL && statbuf->st_nlink != 1) {
log_it(fname, getpid(), "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) {
unlink_user(old_db, u);
link_user(new_db, u);
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...
*/
unlink_user(old_db, u);
free_user(u);
log_it(fname, getpid(), "RELOAD", tabname);
}
u = load_user(crontab_fd, pw, fname);
if (u != NULL) {
u->mtime = statbuf->st_mtime;
link_user(new_db, u);
}
next_crontab:
if (crontab_fd >= 0) {
close(crontab_fd);
}
}
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