1 /* Copyright 1988,1990,1993,1994 by Paul Vixie
2 * All rights reserved
3 */
4
5 /*
6 * Copyright (c) 1997 by Internet Software Consortium
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
13 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
14 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
15 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
16 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
17 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
18 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
19 * SOFTWARE.
20 */
21
22 #if !defined(lint) && !defined(LINT)
23 static const char rcsid[] =
24 "$Id: database.c,v 1.3 1998/08/14 00:32:38 vixie Exp $";
25 #endif
26
27 /* vix 26jan87 [RCS has the log]
28 */
29
30 #include "cron.h"
31
32 #define TMAX(a,b) ((a)>(b)?(a):(b))
33
34 static void process_crontab(const char *, const char *,
35 const char *, struct stat *,
36 cron_db *, cron_db *);
37
38 void
load_database(cron_db * old_db)39 load_database(cron_db *old_db)
40 {
41 struct stat statbuf, syscron_stat, st;
42 cron_db new_db;
43 DIR_T *dp;
44 DIR *dir;
45 user *u, *nu;
46 time_t maxmtime;
47 struct {
48 const char *name;
49 struct stat st;
50 } syscrontabs [] = {
51 { SYSCRONTABS },
52 { LOCALSYSCRONTABS }
53 };
54 int i, ret;
55
56 Debug(DLOAD, ("[%d] load_database()\n", getpid()))
57
58 /* before we start loading any data, do a stat on SPOOL_DIR
59 * so that if anything changes as of this moment (i.e., before we've
60 * cached any of the database), we'll see the changes next time.
61 */
62 if (stat(SPOOL_DIR, &statbuf) < OK) {
63 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR);
64 (void) exit(ERROR_EXIT);
65 }
66
67 /* track system crontab file
68 */
69 if (stat(SYSCRONTAB, &syscron_stat) < OK)
70 syscron_stat.st_mtime = 0;
71
72 maxmtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime);
73
74 for (i = 0; i < nitems(syscrontabs); i++) {
75 if (stat(syscrontabs[i].name, &syscrontabs[i].st) != -1) {
76 maxmtime = TMAX(syscrontabs[i].st.st_mtime, maxmtime);
77 /* Traverse into directory */
78 if (!(dir = opendir(syscrontabs[i].name)))
79 continue;
80 while (NULL != (dp = readdir(dir))) {
81 if (dp->d_name[0] == '.')
82 continue;
83 ret = fstatat(dirfd(dir), dp->d_name, &st, 0);
84 if (ret != 0 || !S_ISREG(st.st_mode))
85 continue;
86 maxmtime = TMAX(st.st_mtime, maxmtime);
87 }
88 closedir(dir);
89 } else {
90 syscrontabs[i].st.st_mtime = 0;
91 }
92 }
93
94 /* if spooldir's mtime has not changed, we don't need to fiddle with
95 * the database.
96 *
97 * Note that old_db->mtime is initialized to 0 in main(), and
98 * so is guaranteed to be different than the stat() mtime the first
99 * time this function is called.
100 */
101 if (old_db->mtime == maxmtime) {
102 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n",
103 getpid()))
104 return;
105 }
106
107 /* something's different. make a new database, moving unchanged
108 * elements from the old database, reloading elements that have
109 * actually changed. Whatever is left in the old database when
110 * we're done is chaff -- crontabs that disappeared.
111 */
112 new_db.mtime = maxmtime;
113 new_db.head = new_db.tail = NULL;
114
115 if (syscron_stat.st_mtime) {
116 process_crontab("root", SYS_NAME,
117 SYSCRONTAB, &syscron_stat,
118 &new_db, old_db);
119 }
120
121 for (i = 0; i < nitems(syscrontabs); i++) {
122 char tabname[MAXPATHLEN];
123 if (syscrontabs[i].st.st_mtime == 0)
124 continue;
125 if (!(dir = opendir(syscrontabs[i].name))) {
126 log_it("CRON", getpid(), "OPENDIR FAILED",
127 syscrontabs[i].name);
128 (void) exit(ERROR_EXIT);
129 }
130
131 while (NULL != (dp = readdir(dir))) {
132 if (dp->d_name[0] == '.')
133 continue;
134 if (fstatat(dirfd(dir), dp->d_name, &st, 0) == 0 &&
135 !S_ISREG(st.st_mode))
136 continue;
137 snprintf(tabname, sizeof(tabname), "%s/%s",
138 syscrontabs[i].name, dp->d_name);
139 process_crontab("root", SYS_NAME, tabname,
140 &syscrontabs[i].st, &new_db, old_db);
141 }
142 closedir(dir);
143 }
144
145 /* we used to keep this dir open all the time, for the sake of
146 * efficiency. however, we need to close it in every fork, and
147 * we fork a lot more often than the mtime of the dir changes.
148 */
149 if (!(dir = opendir(SPOOL_DIR))) {
150 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR);
151 (void) exit(ERROR_EXIT);
152 }
153
154 while (NULL != (dp = readdir(dir))) {
155 char fname[MAXNAMLEN+1], tabname[MAXNAMLEN+1];
156
157 /* avoid file names beginning with ".". this is good
158 * because we would otherwise waste two guaranteed calls
159 * to getpwnam() for . and .., and also because user names
160 * starting with a period are just too nasty to consider.
161 */
162 if (dp->d_name[0] == '.')
163 continue;
164
165 (void) strncpy(fname, dp->d_name, sizeof(fname));
166 fname[sizeof(fname)-1] = '\0';
167
168 if (snprintf(tabname, sizeof tabname, CRON_TAB(fname))
169 >= sizeof(tabname))
170 continue; /* XXX log? */
171
172 process_crontab(fname, fname, tabname,
173 &statbuf, &new_db, old_db);
174 }
175 closedir(dir);
176
177 /* if we don't do this, then when our children eventually call
178 * getpwnam() in do_command.c's child_process to verify MAILTO=,
179 * they will screw us up (and v-v).
180 */
181 endpwent();
182
183 /* whatever's left in the old database is now junk.
184 */
185 Debug(DLOAD, ("unlinking old database:\n"))
186 for (u = old_db->head; u != NULL; u = nu) {
187 Debug(DLOAD, ("\t%s\n", u->name))
188 nu = u->next;
189 unlink_user(old_db, u);
190 free_user(u);
191 }
192
193 /* overwrite the database control block with the new one.
194 */
195 *old_db = new_db;
196 Debug(DLOAD, ("load_database is done\n"))
197 }
198
199 void
link_user(cron_db * db,user * u)200 link_user(cron_db *db, user *u)
201 {
202 if (db->head == NULL)
203 db->head = u;
204 if (db->tail)
205 db->tail->next = u;
206 u->prev = db->tail;
207 u->next = NULL;
208 db->tail = u;
209 }
210
211 void
unlink_user(cron_db * db,user * u)212 unlink_user(cron_db *db, user *u)
213 {
214 if (u->prev == NULL)
215 db->head = u->next;
216 else
217 u->prev->next = u->next;
218
219 if (u->next == NULL)
220 db->tail = u->prev;
221 else
222 u->next->prev = u->prev;
223 }
224
225 user *
find_user(cron_db * db,const char * name)226 find_user(cron_db *db, const char *name)
227 {
228 user *u;
229
230 for (u = db->head; u != NULL; u = u->next)
231 if (strcmp(u->name, name) == 0)
232 break;
233 return (u);
234 }
235
236 static void
process_crontab(const char * uname,const char * fname,const char * tabname,struct stat * statbuf,cron_db * new_db,cron_db * old_db)237 process_crontab(const char *uname, const char *fname, const char *tabname,
238 struct stat *statbuf, cron_db *new_db, cron_db *old_db)
239 {
240 struct passwd *pw = NULL;
241 int crontab_fd = OK - 1;
242 user *u;
243 entry *e;
244 time_t now;
245
246 if (strcmp(fname, SYS_NAME) != 0 && !(pw = getpwnam(uname))) {
247 /* file doesn't have a user in passwd file.
248 */
249 log_it(fname, getpid(), "ORPHAN", "no passwd entry");
250 goto next_crontab;
251 }
252
253 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) {
254 /* crontab not accessible?
255 */
256 log_it(fname, getpid(), "CAN'T OPEN", tabname);
257 goto next_crontab;
258 }
259
260 if (fstat(crontab_fd, statbuf) < OK) {
261 log_it(fname, getpid(), "FSTAT FAILED", tabname);
262 goto next_crontab;
263 }
264
265 Debug(DLOAD, ("\t%s:", fname))
266 u = find_user(old_db, fname);
267 if (u != NULL) {
268 /* if crontab has not changed since we last read it
269 * in, then we can just use our existing entry.
270 */
271 if (u->mtime == statbuf->st_mtime) {
272 Debug(DLOAD, (" [no change, using old data]"))
273 unlink_user(old_db, u);
274 link_user(new_db, u);
275 goto next_crontab;
276 }
277
278 /* before we fall through to the code that will reload
279 * the user, let's deallocate and unlink the user in
280 * the old database. This is more a point of memory
281 * efficiency than anything else, since all leftover
282 * users will be deleted from the old database when
283 * we finish with the crontab...
284 */
285 Debug(DLOAD, (" [delete old data]"))
286 unlink_user(old_db, u);
287 free_user(u);
288 log_it(fname, getpid(), "RELOAD", tabname);
289 }
290 u = load_user(crontab_fd, pw, fname);
291 if (u != NULL) {
292 u->mtime = statbuf->st_mtime;
293 /*
294 * TargetTime == 0 when we're initially populating the database,
295 * and TargetTime > 0 any time after that (i.e. we're reloading
296 * cron.d/ files because they've been created/modified). In the
297 * latter case, we should check for any interval jobs and run
298 * them 'n' seconds from the time the job was loaded/reloaded.
299 * Otherwise, they will not be run until cron is restarted.
300 */
301 if (TargetTime != 0) {
302 now = time(NULL);
303 for (e = u->crontab; e != NULL; e = e->next) {
304 if ((e->flags & INTERVAL) != 0)
305 e->lastexit = now;
306 }
307 }
308 link_user(new_db, u);
309 }
310
311 next_crontab:
312 if (crontab_fd >= OK) {
313 Debug(DLOAD, (" [done]\n"))
314 close(crontab_fd);
315 }
316 }
317