[unix-history] / libexec / crond / database.c

#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;
}
Commit	Line	Data
15637ed4 RG	1	#if !defined(lint) && !defined(LINT)
	2	static char rcsid[] = "$Header: database.c,v 2.1 90/07/18 00:23:51 vixie Exp $";
	3	#endif
	4
	5	/* vix 26jan87 [RCS has the log]
	6	*/
	7
	8	/* Copyright 1988,1990 by Paul Vixie
	9	* All rights reserved
	10	*
	11	* Distribute freely, except: don't remove my name from the source or
	12	* documentation (don't take credit for my work), mark your changes (don't
	13	* get me blamed for your possible bugs), don't alter or remove this
	14	* notice. May be sold if buildable source is provided to buyer. No
	15	* warrantee of any kind, express or implied, is included with this
	16	* software; use at your own risk, responsibility for damages (if any) to
	17	* anyone resulting from the use of this software rests entirely with the
	18	* user.
	19	*
	20	* Send bug reports, bug fixes, enhancements, requests, flames, etc., and
	21	* I'll try to keep a version up to date. I can be reached as follows:
	22	* Paul Vixie, 329 Noe Street, San Francisco, CA, 94114, (415) 864-7013,
	23	* paul@vixie.sf.ca.us \|\| {hoptoad,pacbell,decwrl,crash}!vixie!paul
	24	*/
	25
	26
	27	#include "cron.h"
	28	#include <pwd.h>
	29	#if defined(BSD)
	30	# include <sys/file.h>
	31	# include <sys/dir.h>
	32	#endif
	33	#if defined(ATT)
	34	# include <sys/file.h>
	35	# include <ndir.h>
	36	# include <fcntl.h>
	37	#endif
	38
	39
	40	extern void perror(), exit();
	41
	42
	43	void
	44	load_database(old_db)
	45	cron_db *old_db;
	46	{
	47	extern void link_user(), unlink_user(), free_user();
	48	extern user load_user(), find_user();
	49	extern char *env_get();
	50
	51	static DIR *dir = NULL;
	52
	53	struct stat statbuf;
	54	struct direct *dp;
	55	cron_db new_db;
	56	user *u;
	57
	58	Debug(DLOAD, ("[%d] load_database()\n", getpid()))
	59
	60	/* before we start loading any data, do a stat on SPOOL_DIR
	61	* so that if anything changes as of this moment (i.e., before we've
	62	* cached any of the database), we'll see the changes next time.
	63	*/
	64	if (stat(SPOOL_DIR, &statbuf) < OK)
65	{
66	log_it("CROND", getpid(), "STAT FAILED", SPOOL_DIR);
67	(void) exit(ERROR_EXIT);
68	}
69
70	/* if spooldir's mtime has not changed, we don't need to fiddle with
71	* the database. Note that if /etc/passwd changes (like, someone's
72	* UID/GID/HOME/SHELL, we won't see it. Maybe we should
73	* keep an mtime for the passwd file? HINT
74	*
75	* Note that old_db->mtime is initialized to 0 in main(), and
76	* so is guaranteed to be different than the stat() mtime the first
77	* time this function is called.
78	*/
79	if (old_db->mtime == statbuf.st_mtime)
80	{
81	Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n",
82	getpid()))
83	return;
84	}
85
86	/* make sure the dir is open. only happens the first time, since
87	* the DIR is static and we don't close it. Rewind the dir.
88	*/
89	if (dir == NULL)
90	{
91	if (!(dir = opendir(SPOOL_DIR)))
92	{
93	log_it("CROND", getpid(), "OPENDIR FAILED", SPOOL_DIR);
94	(void) exit(ERROR_EXIT);
95	}
96	}
97	(void) rewinddir(dir);
98
99	/* something's different. make a new database, moving unchanged
100	* elements from the old database, reloading elements that have
101	* actually changed. Whatever is left in the old database when
102	* we're done is chaff -- crontabs that disappeared.
103	*/
104	new_db.mtime = statbuf.st_mtime;
105	new_db.head = new_db.tail = NULL;
106
107	while (NULL != (dp = readdir(dir)))
108	{
109	extern struct passwd *getpwnam();
110	struct passwd *pw;
111	int crontab_fd;
112	char fname[MAXNAMLEN+1],
113	tabname[MAXNAMLEN+1];
114
115	(void) strncpy(fname, dp->d_name, (int) dp->d_namlen);
116	fname[dp->d_namlen] = '\0';
117
118	/* avoid file names beginning with ".". this is good
119	* because we would otherwise waste two guaranteed calls
120	* to getpwnam() for . and .., and also because user names
121	* starting with a period are just too nasty to consider.
122	*/
123	if (fname[0] == '.')
124	goto next_crontab;
125
126	if (NULL == (pw = getpwnam(fname)))
127	{
128	/* file doesn't have a user in passwd file.
129	*/
130	log_it(fname, getpid(), "ORPHAN", "no passwd entry");
131	goto next_crontab;
132	}
133
134	sprintf(tabname, CRON_TAB(fname));
135	if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK)
136	{
137	/* crontab not accessible?
138	*/
139	log_it(fname, getpid(), "CAN'T OPEN", tabname);
140	goto next_crontab;
141	}
142
143	if (fstat(crontab_fd, &statbuf) < OK)
144	{
145	log_it(fname, getpid(), "FSTAT FAILED", tabname);
146	goto next_crontab;
147	}
148
149	Debug(DLOAD, ("\t%s:", fname))
150	u = find_user(old_db, fname);
151	if (u != NULL)
152	{
153	/* if crontab has not changed since we last read it
154	* in, then we can just use our existing entry.
155	* note that we do not check for changes in the
156	* passwd entry (uid, home dir, etc). HINT
157	*/
158	if (u->mtime == statbuf.st_mtime)
159	{
160	Debug(DLOAD, (" [no change, using old data]"))
161	unlink_user(old_db, u);
162	link_user(&new_db, u);
163	goto next_crontab;
164	}
165
166	/* before we fall through to the code that will reload
167	* the user, let's deallocate and unlink the user in
168	* the old database. This is more a point of memory
169	* efficiency than anything else, since all leftover
170	* users will be deleted from the old database when
171	* we finish with the crontab...
172	*/
173	Debug(DLOAD, (" [delete old data]"))
174	unlink_user(old_db, u);
175	free_user(u);
176	}
177	u = load_user(
178	crontab_fd,
179	pw->pw_name,
180	pw->pw_uid,
181	pw->pw_gid,
182	pw->pw_dir,
183	pw->pw_shell
184	);
185	if (u != NULL)
186	{
187	u->mtime = statbuf.st_mtime;
188	link_user(&new_db, u);
189	}
190	next_crontab:
191	if (crontab_fd >= OK) {
192	Debug(DLOAD, (" [done]\n"))
193	close(crontab_fd);
194	}
195	}
196	/* if we don't do this, then when our children eventually call
197	* getpwnam() in do_command.c's child_process to verify MAILTO=,
198	* they will screw us up (and v-v).
199	*
200	* (this was lots of fun to find...)
201	*/
202	endpwent();
203
204	/* whatever's left in the old database is now junk.
205	*/
206	Debug(DLOAD, ("unlinking old database:\n"))
207	for (u = old_db->head; u != NULL; u = u->next)
208	{
209	Debug(DLOAD, ("\t%s\n", env_get(USERENV, u->envp)))
210	unlink_user(old_db, u);
211	free_user(u);
212	}
213
214	/* overwrite the database control block with the new one.
215	*/
216	Debug(DLOAD, ("installing new database\n"))
217	#if defined(BSD)
218	/* BSD has structure assignments */
219	*old_db = new_db;
220	#endif
221	#if defined(ATT)
222	/* ATT, well, I don't know. Use memcpy(). */
223	memcpy(old_db, &new_db, sizeof(cron_db));
224	#endif
225	Debug(DLOAD, ("load_database is done\n"))
226	}
227
228
229	void
230	link_user(db, u)
231	cron_db *db;
232	user *u;
233	{
234	if (db->head == NULL)
235	db->head = u;
236	if (db->tail)
237	db->tail->next = u;
238	u->prev = db->tail;
239	u->next = NULL;
240	db->tail = u;
241	}
242
243
244	void
245	unlink_user(db, u)
246	cron_db *db;
247	user *u;
248	{
249	if (u->prev == NULL)
250	db->head = u->next;
251	else
252	u->prev->next = u->next;
253
254	if (u->next == NULL)
255	db->tail = u->prev;
256	else
257	u->next->prev = u->prev;
258	}
259
260
261	user *
262	find_user(db, name)
263	cron_db *db;
264	char *name;
265	{
266	char *env_get();
267	user *u;
268
269	for (u = db->head; u != NULL; u = u->next)
270	if (!strcmp(env_get(USERENV, u->envp), name))
271	break;
272	return u;
273	}