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 char rcsid[] = "$Id: database.c,v 1.3 1997/12/22 08:10:42 deraadt Exp $"; 20 #endif 21 22 /* vix 26jan87 [RCS has the log] 23 */ 24 25 26 #include "cron.h" 27 #include <fcntl.h> 28 #include <sys/stat.h> 29 #include <sys/file.h> 30 31 32 #define TMAX(a,b) ((a)>(b)?(a):(b)) 33 #define HASH(a,b) ((a)+(b)) 34 35 static void process_crontab __P((char *, char *, char *, 36 struct stat *, 37 cron_db *, cron_db *)); 38 39 40 void 41 load_database(old_db) 42 cron_db *old_db; 43 { 44 DIR *dir; 45 struct stat statbuf; 46 struct stat syscron_stat; 47 DIR_T *dp; 48 cron_db new_db; 49 user *u, *nu; 50 51 Debug(DLOAD, ("[%d] load_database()\n", getpid())) 52 53 /* before we start loading any data, do a stat on SPOOL_DIR 54 * so that if anything changes as of this moment (i.e., before we've 55 * cached any of the database), we'll see the changes next time. 56 */ 57 if (stat(SPOOL_DIR, &statbuf) < OK) { 58 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); 59 (void) exit(ERROR_EXIT); 60 } 61 62 /* track system crontab file 63 */ 64 if (stat(SYSCRONTAB, &syscron_stat) < OK) 65 syscron_stat.st_mtime = 0; 66 67 /* if spooldir's mtime has not changed, we don't need to fiddle with 68 * the database. 69 * 70 * Note that old_db->mtime is initialized to 0 in main(), and 71 * so is guaranteed to be different than the stat() mtime the first 72 * time this function is called. 73 */ 74 if (old_db->mtime == HASH(statbuf.st_mtime, syscron_stat.st_mtime)) { 75 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", 76 getpid())) 77 return; 78 } 79 80 /* something's different. make a new database, moving unchanged 81 * elements from the old database, reloading elements that have 82 * actually changed. Whatever is left in the old database when 83 * we're done is chaff -- crontabs that disappeared. 84 */ 85 new_db.mtime = HASH(statbuf.st_mtime, syscron_stat.st_mtime); 86 new_db.head = new_db.tail = NULL; 87 88 if (syscron_stat.st_mtime) { 89 process_crontab("root", "*system*", 90 SYSCRONTAB, &syscron_stat, 91 &new_db, old_db); 92 } 93 94 /* we used to keep this dir open all the time, for the sake of 95 * efficiency. however, we need to close it in every fork, and 96 * we fork a lot more often than the mtime of the dir changes. 97 */ 98 if (!(dir = opendir(SPOOL_DIR))) { 99 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); 100 (void) exit(ERROR_EXIT); 101 } 102 103 while (NULL != (dp = readdir(dir))) { 104 char fname[MAXNAMLEN+1], 105 tabname[MAXPATHLEN]; 106 107 /* avoid file names beginning with ".". this is good 108 * because we would otherwise waste two guaranteed calls 109 * to getpwnam() for . and .., and also because user names 110 * starting with a period are just too nasty to consider. 111 */ 112 if (dp->d_name[0] == '.') 113 continue; 114 115 (void) strcpy(fname, dp->d_name); 116 sprintf(tabname, CRON_TAB(fname)); 117 118 process_crontab(fname, fname, tabname, 119 &statbuf, &new_db, old_db); 120 } 121 closedir(dir); 122 123 /* if we don't do this, then when our children eventually call 124 * getpwnam() in do_command.c's child_process to verify MAILTO=, 125 * they will screw us up (and v-v). 126 */ 127 endpwent(); 128 129 /* whatever's left in the old database is now junk. 130 */ 131 Debug(DLOAD, ("unlinking old database:\n")) 132 for (u = old_db->head; u != NULL; u = nu) { 133 Debug(DLOAD, ("\t%s\n", u->name)) 134 nu = u->next; 135 unlink_user(old_db, u); 136 free_user(u); 137 } 138 139 /* overwrite the database control block with the new one. 140 */ 141 *old_db = new_db; 142 Debug(DLOAD, ("load_database is done\n")) 143 } 144 145 146 void 147 link_user(db, u) 148 cron_db *db; 149 user *u; 150 { 151 if (db->head == NULL) 152 db->head = u; 153 if (db->tail) 154 db->tail->next = u; 155 u->prev = db->tail; 156 u->next = NULL; 157 db->tail = u; 158 } 159 160 161 void 162 unlink_user(db, u) 163 cron_db *db; 164 user *u; 165 { 166 if (u->prev == NULL) 167 db->head = u->next; 168 else 169 u->prev->next = u->next; 170 171 if (u->next == NULL) 172 db->tail = u->prev; 173 else 174 u->next->prev = u->prev; 175 } 176 177 178 user * 179 find_user(db, name) 180 cron_db *db; 181 char *name; 182 { 183 char *env_get(); 184 user *u; 185 186 for (u = db->head; u != NULL; u = u->next) 187 if (!strcmp(u->name, name)) 188 break; 189 return u; 190 } 191 192 193 static void 194 process_crontab(uname, fname, tabname, statbuf, new_db, old_db) 195 char *uname; 196 char *fname; 197 char *tabname; 198 struct stat *statbuf; 199 cron_db *new_db; 200 cron_db *old_db; 201 { 202 struct passwd *pw = NULL; 203 int crontab_fd = OK - 1; 204 user *u; 205 206 if (strcmp(fname, "*system*") && !(pw = getpwnam(uname))) { 207 /* file doesn't have a user in passwd file. 208 */ 209 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 210 goto next_crontab; 211 } 212 213 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 214 /* crontab not accessible? 215 */ 216 log_it(fname, getpid(), "CAN'T OPEN", tabname); 217 goto next_crontab; 218 } 219 220 if (fstat(crontab_fd, statbuf) < OK) { 221 log_it(fname, getpid(), "FSTAT FAILED", tabname); 222 goto next_crontab; 223 } 224 225 Debug(DLOAD, ("\t%s:", fname)) 226 u = find_user(old_db, fname); 227 if (u != NULL) { 228 /* if crontab has not changed since we last read it 229 * in, then we can just use our existing entry. 230 */ 231 if (u->mtime == statbuf->st_mtime) { 232 Debug(DLOAD, (" [no change, using old data]")) 233 unlink_user(old_db, u); 234 link_user(new_db, u); 235 goto next_crontab; 236 } 237 238 /* before we fall through to the code that will reload 239 * the user, let's deallocate and unlink the user in 240 * the old database. This is more a point of memory 241 * efficiency than anything else, since all leftover 242 * users will be deleted from the old database when 243 * we finish with the crontab... 244 */ 245 Debug(DLOAD, (" [delete old data]")) 246 unlink_user(old_db, u); 247 free_user(u); 248 log_it(fname, getpid(), "RELOAD", tabname); 249 } 250 u = load_user(crontab_fd, pw, fname); 251 if (u != NULL) { 252 u->mtime = statbuf->st_mtime; 253 link_user(new_db, u); 254 } 255 256 next_crontab: 257 if (crontab_fd >= OK) { 258 Debug(DLOAD, (" [done]\n")) 259 close(crontab_fd); 260 } 261 } 262