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; 48 DIR_T *dp; 49 cron_db new_db; 50 user *u, *nu; 51 52 Debug(DLOAD, ("[%d] load_database()\n", getpid())) 53 54 /* before we start loading any data, do a stat on SPOOL_DIR 55 * so that if anything changes as of this moment (i.e., before we've 56 * cached any of the database), we'll see the changes next time. 57 */ 58 if (stat(SPOOL_DIR, &statbuf) < OK) { 59 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); 60 (void) exit(ERROR_EXIT); 61 } 62 63 /* track system crontab file 64 */ 65 if (stat(SYSCRONTAB, &syscron_stat) < OK) 66 syscron_stat.st_mtime = 0; 67 68 /* if spooldir's mtime has not changed, we don't need to fiddle with 69 * the database. 70 * 71 * Note that old_db->mtime is initialized to 0 in main(), and 72 * so is guaranteed to be different than the stat() mtime the first 73 * time this function is called. 74 */ 75 if (old_db->mtime == TMAX(statbuf.st_mtime, syscron_stat.st_mtime)) { 76 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", 77 getpid())) 78 return; 79 } 80 81 /* something's different. make a new database, moving unchanged 82 * elements from the old database, reloading elements that have 83 * actually changed. Whatever is left in the old database when 84 * we're done is chaff -- crontabs that disappeared. 85 */ 86 new_db.mtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); 87 new_db.head = new_db.tail = NULL; 88 89 if (syscron_stat.st_mtime) { 90 process_crontab("root", SYS_NAME, 91 SYSCRONTAB, &syscron_stat, 92 &new_db, old_db); 93 } 94 95 /* we used to keep this dir open all the time, for the sake of 96 * efficiency. however, we need to close it in every fork, and 97 * we fork a lot more often than the mtime of the dir changes. 98 */ 99 if (!(dir = opendir(SPOOL_DIR))) { 100 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); 101 (void) exit(ERROR_EXIT); 102 } 103 104 while (NULL != (dp = readdir(dir))) { 105 char fname[MAXNAMLEN+1], 106 tabname[MAXNAMLEN+1]; 107 108 /* avoid file names beginning with ".". this is good 109 * because we would otherwise waste two guaranteed calls 110 * to getpwnam() for . and .., and also because user names 111 * starting with a period are just too nasty to consider. 112 */ 113 if (dp->d_name[0] == '.') 114 continue; 115 116 (void) strncpy(fname, dp->d_name, sizeof(fname)); 117 fname[sizeof(fname)-1] = '\0'; 118 (void) snprintf(tabname, sizeof tabname, CRON_TAB(fname)); 119 120 process_crontab(fname, fname, tabname, 121 &statbuf, &new_db, old_db); 122 } 123 closedir(dir); 124 125 /* if we don't do this, then when our children eventually call 126 * getpwnam() in do_command.c's child_process to verify MAILTO=, 127 * they will screw us up (and v-v). 128 */ 129 endpwent(); 130 131 /* whatever's left in the old database is now junk. 132 */ 133 Debug(DLOAD, ("unlinking old database:\n")) 134 for (u = old_db->head; u != NULL; u = nu) { 135 Debug(DLOAD, ("\t%s\n", u->name)) 136 nu = u->next; 137 unlink_user(old_db, u); 138 free_user(u); 139 } 140 141 /* overwrite the database control block with the new one. 142 */ 143 *old_db = new_db; 144 Debug(DLOAD, ("load_database is done\n")) 145 } 146 147 148 void 149 link_user(db, u) 150 cron_db *db; 151 user *u; 152 { 153 if (db->head == NULL) 154 db->head = u; 155 if (db->tail) 156 db->tail->next = u; 157 u->prev = db->tail; 158 u->next = NULL; 159 db->tail = u; 160 } 161 162 163 void 164 unlink_user(db, u) 165 cron_db *db; 166 user *u; 167 { 168 if (u->prev == NULL) 169 db->head = u->next; 170 else 171 u->prev->next = u->next; 172 173 if (u->next == NULL) 174 db->tail = u->prev; 175 else 176 u->next->prev = u->prev; 177 } 178 179 180 user * 181 find_user(db, name) 182 cron_db *db; 183 char *name; 184 { 185 char *env_get(); 186 user *u; 187 188 for (u = db->head; u != NULL; u = u->next) 189 if (!strcmp(u->name, name)) 190 break; 191 return u; 192 } 193 194 195 static void 196 process_crontab(uname, fname, tabname, statbuf, new_db, old_db) 197 char *uname; 198 char *fname; 199 char *tabname; 200 struct stat *statbuf; 201 cron_db *new_db; 202 cron_db *old_db; 203 { 204 struct passwd *pw = NULL; 205 int crontab_fd = OK - 1; 206 user *u; 207 208 if (strcmp(fname, SYS_NAME) && !(pw = getpwnam(uname))) { 209 /* file doesn't have a user in passwd file. 210 */ 211 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 212 goto next_crontab; 213 } 214 215 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 216 /* crontab not accessible? 217 */ 218 log_it(fname, getpid(), "CAN'T OPEN", tabname); 219 goto next_crontab; 220 } 221 222 if (fstat(crontab_fd, statbuf) < OK) { 223 log_it(fname, getpid(), "FSTAT FAILED", tabname); 224 goto next_crontab; 225 } 226 227 Debug(DLOAD, ("\t%s:", fname)) 228 u = find_user(old_db, fname); 229 if (u != NULL) { 230 /* if crontab has not changed since we last read it 231 * in, then we can just use our existing entry. 232 */ 233 if (u->mtime == statbuf->st_mtime) { 234 Debug(DLOAD, (" [no change, using old data]")) 235 unlink_user(old_db, u); 236 link_user(new_db, u); 237 goto next_crontab; 238 } 239 240 /* before we fall through to the code that will reload 241 * the user, let's deallocate and unlink the user in 242 * the old database. This is more a point of memory 243 * efficiency than anything else, since all leftover 244 * users will be deleted from the old database when 245 * we finish with the crontab... 246 */ 247 Debug(DLOAD, (" [delete old data]")) 248 unlink_user(old_db, u); 249 free_user(u); 250 log_it(fname, getpid(), "RELOAD", tabname); 251 } 252 u = load_user(crontab_fd, pw, fname); 253 if (u != NULL) { 254 u->mtime = statbuf->st_mtime; 255 link_user(new_db, u); 256 } 257 258 next_crontab: 259 if (crontab_fd >= OK) { 260 Debug(DLOAD, (" [done]\n")) 261 close(crontab_fd); 262 } 263 } 264