This is database.c in view mode; [Download] [Up]
#if !defined(lint) && !defined(LINT)
static char rcsid[] = "$Header: database.c,v 2.1 90/07/18 00:23:51 vixie Exp $";
#endif
/* vix 26jan87 [RCS has the log]
*/
/* Copyright 1988,1990 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, 329 Noe Street, San Francisco, CA, 94114, (415) 864-7013,
* paul@vixie.sf.ca.us || {hoptoad,pacbell,decwrl,crash}!vixie!paul
*/
#include "cron.h"
#include <pwd.h>
#if defined(BSD)
# include <sys/file.h>
# include <sys/dir.h>
#endif
#if defined(ATT)
# include <sys/file.h>
# include <ndir.h>
# include <fcntl.h>
#endif
extern void perror(), exit();
void
load_database(old_db)
cron_db *old_db;
{
extern void link_user(), unlink_user(), free_user();
extern user *load_user(), *find_user();
extern char *env_get();
static DIR *dir = NULL;
struct stat statbuf;
struct direct *dp;
cron_db new_db;
user *u;
Debug(DLOAD, ("[%d] load_database()\n", getpid()))
/* 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) < OK)
{
log_it("CROND", getpid(), "STAT FAILED", SPOOL_DIR);
(void) exit(ERROR_EXIT);
}
/* if spooldir's mtime has not changed, we don't need to fiddle with
* the database. Note that if /etc/passwd changes (like, someone's
* UID/GID/HOME/SHELL, we won't see it. Maybe we should
* keep an mtime for the passwd file? HINT
*
* 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 == statbuf.st_mtime)
{
Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n",
getpid()))
return;
}
/* make sure the dir is open. only happens the first time, since
* the DIR is static and we don't close it. Rewind the dir.
*/
if (dir == NULL)
{
if (!(dir = opendir(SPOOL_DIR)))
{
log_it("CROND", getpid(), "OPENDIR FAILED", SPOOL_DIR);
(void) exit(ERROR_EXIT);
}
}
(void) rewinddir(dir);
/* 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 = statbuf.st_mtime;
new_db.head = new_db.tail = NULL;
while (NULL != (dp = readdir(dir)))
{
extern struct passwd *getpwnam();
struct passwd *pw;
int crontab_fd;
char fname[MAXNAMLEN+1],
tabname[MAXNAMLEN+1];
(void) strncpy(fname, dp->d_name, (int) dp->d_namlen);
fname[dp->d_namlen] = '\0';
/* 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 (fname[0] == '.')
goto next_crontab;
if (NULL == (pw = getpwnam(fname)))
{
/* file doesn't have a user in passwd file.
*/
log_it(fname, getpid(), "ORPHAN", "no passwd entry");
goto next_crontab;
}
sprintf(tabname, CRON_TAB(fname));
if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK)
{
/* crontab not accessible?
*/
log_it(fname, getpid(), "CAN'T OPEN", tabname);
goto next_crontab;
}
if (fstat(crontab_fd, &statbuf) < OK)
{
log_it(fname, getpid(), "FSTAT FAILED", tabname);
goto next_crontab;
}
Debug(DLOAD, ("\t%s:", fname))
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.
* note that we do not check for changes in the
* passwd entry (uid, home dir, etc). HINT
*/
if (u->mtime == statbuf.st_mtime)
{
Debug(DLOAD, (" [no change, using old data]"))
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...
*/
Debug(DLOAD, (" [delete old data]"))
unlink_user(old_db, u);
free_user(u);
}
u = load_user(
crontab_fd,
pw->pw_name,
pw->pw_uid,
pw->pw_gid,
pw->pw_dir,
pw->pw_shell
);
if (u != NULL)
{
u->mtime = statbuf.st_mtime;
link_user(&new_db, u);
}
next_crontab:
if (crontab_fd >= OK) {
Debug(DLOAD, (" [done]\n"))
close(crontab_fd);
}
}
/* 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).
*
* (this was lots of fun to find...)
*/
endpwent();
/* whatever's left in the old database is now junk.
*/
Debug(DLOAD, ("unlinking old database:\n"))
for (u = old_db->head; u != NULL; u = u->next)
{
Debug(DLOAD, ("\t%s\n", env_get(USERENV, u->envp)))
unlink_user(old_db, u);
free_user(u);
}
/* overwrite the database control block with the new one.
*/
Debug(DLOAD, ("installing new database\n"))
#if defined(BSD)
/* BSD has structure assignments */
*old_db = new_db;
#endif
#if defined(ATT)
/* ATT, well, I don't know. Use memcpy(). */
memcpy(old_db, &new_db, sizeof(cron_db));
#endif
Debug(DLOAD, ("load_database is done\n"))
}
void
link_user(db, u)
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(db, u)
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(db, name)
cron_db *db;
char *name;
{
char *env_get();
user *u;
for (u = db->head; u != NULL; u = u->next)
if (!strcmp(env_get(USERENV, u->envp), name))
break;
return u;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.