1 /* Copyright 1988,1990,1993,1994 by Paul Vixie 2 * All rights reserved 3 * 4 * Distribute freely, except: don't remove my name from the source or 5 * documentation (don't take credit for my work), mark your changes (don't 6 * get me blamed for your possible bugs), don't alter or remove this 7 * notice. May be sold if buildable source is provided to buyer. No 8 * warrantee of any kind, express or implied, is included with this 9 * software; use at your own risk, responsibility for damages (if any) to 10 * anyone resulting from the use of this software rests entirely with the 11 * user. 12 * 13 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and 14 * I'll try to keep a version up to date. I can be reached as follows: 15 * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul 16 */ 17 18 #if !defined(lint) && !defined(LINT) 19 static const char rcsid[] = 20 "$FreeBSD$"; 21 #endif 22 23 /* vix 26jan87 [RCS has the log] 24 */ 25 26 27 #include "cron.h" 28 #include <fcntl.h> 29 #include <sys/stat.h> 30 #include <sys/file.h> 31 32 33 #define TMAX(a,b) ((a)>(b)?(a):(b)) 34 35 36 static void process_crontab(char *, char *, char *, 37 struct stat *, 38 cron_db *, cron_db *); 39 40 41 void 42 load_database(old_db) 43 cron_db *old_db; 44 { 45 DIR *dir; 46 struct stat statbuf; 47 struct stat syscron_stat, st; 48 time_t maxmtime; 49 DIR_T *dp; 50 cron_db new_db; 51 user *u, *nu; 52 struct { 53 const char *name; 54 struct stat st; 55 } syscrontabs [] = { 56 { SYSCRONTABS }, 57 { LOCALSYSCRONTABS } 58 }; 59 int i; 60 61 Debug(DLOAD, ("[%d] load_database()\n", getpid())) 62 63 /* before we start loading any data, do a stat on SPOOL_DIR 64 * so that if anything changes as of this moment (i.e., before we've 65 * cached any of the database), we'll see the changes next time. 66 */ 67 if (stat(SPOOL_DIR, &statbuf) < OK) { 68 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); 69 (void) exit(ERROR_EXIT); 70 } 71 72 /* track system crontab file 73 */ 74 if (stat(SYSCRONTAB, &syscron_stat) < OK) 75 syscron_stat.st_mtime = 0; 76 77 maxmtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); 78 79 for (i = 0; i < nitems(syscrontabs); i++) { 80 if (stat(syscrontabs[i].name, &syscrontabs[i].st) != -1) { 81 maxmtime = TMAX(syscrontabs[i].st.st_mtime, maxmtime); 82 } else { 83 syscrontabs[i].st.st_mtime = 0; 84 } 85 } 86 87 /* if spooldir's mtime has not changed, we don't need to fiddle with 88 * the database. 89 * 90 * Note that old_db->mtime is initialized to 0 in main(), and 91 * so is guaranteed to be different than the stat() mtime the first 92 * time this function is called. 93 */ 94 if (old_db->mtime == maxmtime) { 95 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", 96 getpid())) 97 return; 98 } 99 100 /* something's different. make a new database, moving unchanged 101 * elements from the old database, reloading elements that have 102 * actually changed. Whatever is left in the old database when 103 * we're done is chaff -- crontabs that disappeared. 104 */ 105 new_db.mtime = maxmtime; 106 new_db.head = new_db.tail = NULL; 107 108 if (syscron_stat.st_mtime) { 109 process_crontab("root", SYS_NAME, 110 SYSCRONTAB, &syscron_stat, 111 &new_db, old_db); 112 } 113 114 for (i = 0; i < nitems(syscrontabs); i++) { 115 char tabname[MAXPATHLEN]; 116 if (syscrontabs[i].st.st_mtime == 0) 117 continue; 118 if (!(dir = opendir(syscrontabs[i].name))) { 119 log_it("CRON", getpid(), "OPENDIR FAILED", 120 syscrontabs[i].name); 121 (void) exit(ERROR_EXIT); 122 } 123 124 while (NULL != (dp = readdir(dir))) { 125 if (dp->d_name[0] == '.') 126 continue; 127 if (fstatat(dirfd(dir), dp->d_name, &st, 0) == 0 && 128 !S_ISREG(st.st_mode)) 129 continue; 130 snprintf(tabname, sizeof(tabname), "%s/%s", 131 syscrontabs[i].name, dp->d_name); 132 process_crontab("root", SYS_NAME, tabname, 133 &syscrontabs[i].st, &new_db, old_db); 134 } 135 closedir(dir); 136 } 137 138 /* we used to keep this dir open all the time, for the sake of 139 * efficiency. however, we need to close it in every fork, and 140 * we fork a lot more often than the mtime of the dir changes. 141 */ 142 if (!(dir = opendir(SPOOL_DIR))) { 143 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); 144 (void) exit(ERROR_EXIT); 145 } 146 147 while (NULL != (dp = readdir(dir))) { 148 char fname[MAXNAMLEN+1], 149 tabname[MAXNAMLEN+1]; 150 151 /* avoid file names beginning with ".". this is good 152 * because we would otherwise waste two guaranteed calls 153 * to getpwnam() for . and .., and also because user names 154 * starting with a period are just too nasty to consider. 155 */ 156 if (dp->d_name[0] == '.') 157 continue; 158 159 (void) strncpy(fname, dp->d_name, sizeof(fname)); 160 fname[sizeof(fname)-1] = '\0'; 161 (void) snprintf(tabname, sizeof tabname, CRON_TAB(fname)); 162 163 process_crontab(fname, fname, tabname, 164 &statbuf, &new_db, old_db); 165 } 166 closedir(dir); 167 168 /* if we don't do this, then when our children eventually call 169 * getpwnam() in do_command.c's child_process to verify MAILTO=, 170 * they will screw us up (and v-v). 171 */ 172 endpwent(); 173 174 /* whatever's left in the old database is now junk. 175 */ 176 Debug(DLOAD, ("unlinking old database:\n")) 177 for (u = old_db->head; u != NULL; u = nu) { 178 Debug(DLOAD, ("\t%s\n", u->name)) 179 nu = u->next; 180 unlink_user(old_db, u); 181 free_user(u); 182 } 183 184 /* overwrite the database control block with the new one. 185 */ 186 *old_db = new_db; 187 Debug(DLOAD, ("load_database is done\n")) 188 } 189 190 191 void 192 link_user(db, u) 193 cron_db *db; 194 user *u; 195 { 196 if (db->head == NULL) 197 db->head = u; 198 if (db->tail) 199 db->tail->next = u; 200 u->prev = db->tail; 201 u->next = NULL; 202 db->tail = u; 203 } 204 205 206 void 207 unlink_user(db, u) 208 cron_db *db; 209 user *u; 210 { 211 if (u->prev == NULL) 212 db->head = u->next; 213 else 214 u->prev->next = u->next; 215 216 if (u->next == NULL) 217 db->tail = u->prev; 218 else 219 u->next->prev = u->prev; 220 } 221 222 223 user * 224 find_user(db, name) 225 cron_db *db; 226 char *name; 227 { 228 char *env_get(); 229 user *u; 230 231 for (u = db->head; u != NULL; u = u->next) 232 if (!strcmp(u->name, name)) 233 break; 234 return u; 235 } 236 237 238 static void 239 process_crontab(uname, fname, tabname, statbuf, new_db, old_db) 240 char *uname; 241 char *fname; 242 char *tabname; 243 struct stat *statbuf; 244 cron_db *new_db; 245 cron_db *old_db; 246 { 247 struct passwd *pw = NULL; 248 int crontab_fd = OK - 1; 249 user *u; 250 251 if (strcmp(fname, SYS_NAME) && !(pw = getpwnam(uname))) { 252 /* file doesn't have a user in passwd file. 253 */ 254 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 255 goto next_crontab; 256 } 257 258 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 259 /* crontab not accessible? 260 */ 261 log_it(fname, getpid(), "CAN'T OPEN", tabname); 262 goto next_crontab; 263 } 264 265 if (fstat(crontab_fd, statbuf) < OK) { 266 log_it(fname, getpid(), "FSTAT FAILED", tabname); 267 goto next_crontab; 268 } 269 270 Debug(DLOAD, ("\t%s:", fname)) 271 u = find_user(old_db, fname); 272 if (u != NULL) { 273 /* if crontab has not changed since we last read it 274 * in, then we can just use our existing entry. 275 */ 276 if (u->mtime == statbuf->st_mtime) { 277 Debug(DLOAD, (" [no change, using old data]")) 278 unlink_user(old_db, u); 279 link_user(new_db, u); 280 goto next_crontab; 281 } 282 283 /* before we fall through to the code that will reload 284 * the user, let's deallocate and unlink the user in 285 * the old database. This is more a point of memory 286 * efficiency than anything else, since all leftover 287 * users will be deleted from the old database when 288 * we finish with the crontab... 289 */ 290 Debug(DLOAD, (" [delete old data]")) 291 unlink_user(old_db, u); 292 free_user(u); 293 log_it(fname, getpid(), "RELOAD", tabname); 294 } 295 u = load_user(crontab_fd, pw, fname); 296 if (u != NULL) { 297 u->mtime = statbuf->st_mtime; 298 link_user(new_db, u); 299 } 300 301 next_crontab: 302 if (crontab_fd >= OK) { 303 Debug(DLOAD, (" [done]\n")) 304 close(crontab_fd); 305 } 306 } 307