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 * $FreeBSD: src/usr.sbin/cron/cron/database.c,v 1.8 1999/08/28 01:15:50 peter Exp $ 18 * $DragonFly: src/usr.sbin/cron/cron/database.c,v 1.5 2004/12/18 22:48:03 swildner Exp $ 19 */ 20 21 /* vix 26jan87 [RCS has the log] 22 */ 23 24 25 #include "cron.h" 26 #include <fcntl.h> 27 #include <sys/stat.h> 28 #include <sys/file.h> 29 30 31 #define TMAX(a,b) ((a)>(b)?(a):(b)) 32 33 34 static void process_crontab(char *, char *, char *, 35 struct stat *, 36 cron_db *, cron_db *); 37 38 39 void 40 load_database(cron_db *old_db) 41 { 42 DIR *dir; 43 struct stat statbuf; 44 struct stat syscron_stat; 45 DIR_T *dp; 46 cron_db new_db; 47 user *u, *nu; 48 49 Debug(DLOAD, ("[%d] load_database()\n", getpid())) 50 51 /* before we start loading any data, do a stat on SPOOL_DIR 52 * so that if anything changes as of this moment (i.e., before we've 53 * cached any of the database), we'll see the changes next time. 54 */ 55 if (stat(SPOOL_DIR, &statbuf) < OK) { 56 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); 57 exit(ERROR_EXIT); 58 } 59 60 /* track system crontab file 61 */ 62 if (stat(SYSCRONTAB, &syscron_stat) < OK) 63 syscron_stat.st_mtime = 0; 64 65 /* if spooldir's mtime has not changed, we don't need to fiddle with 66 * the database. 67 * 68 * Note that old_db->mtime is initialized to 0 in main(), and 69 * so is guaranteed to be different than the stat() mtime the first 70 * time this function is called. 71 */ 72 if (old_db->mtime == TMAX(statbuf.st_mtime, syscron_stat.st_mtime)) { 73 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", 74 getpid())) 75 return; 76 } 77 78 /* something's different. make a new database, moving unchanged 79 * elements from the old database, reloading elements that have 80 * actually changed. Whatever is left in the old database when 81 * we're done is chaff -- crontabs that disappeared. 82 */ 83 new_db.mtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); 84 new_db.head = new_db.tail = NULL; 85 86 if (syscron_stat.st_mtime) { 87 process_crontab("root", "*system*", 88 SYSCRONTAB, &syscron_stat, 89 &new_db, old_db); 90 } 91 92 /* we used to keep this dir open all the time, for the sake of 93 * efficiency. however, we need to close it in every fork, and 94 * we fork a lot more often than the mtime of the dir changes. 95 */ 96 if (!(dir = opendir(SPOOL_DIR))) { 97 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); 98 exit(ERROR_EXIT); 99 } 100 101 while (NULL != (dp = readdir(dir))) { 102 char fname[MAXNAMLEN+1], 103 tabname[MAXNAMLEN+1]; 104 105 /* avoid file names beginning with ".". this is good 106 * because we would otherwise waste two guaranteed calls 107 * to getpwnam() for . and .., and also because user names 108 * starting with a period are just too nasty to consider. 109 */ 110 if (dp->d_name[0] == '.') 111 continue; 112 113 strncpy(fname, dp->d_name, sizeof(fname)); 114 fname[sizeof(fname)-1] = '\0'; 115 snprintf(tabname, sizeof tabname, CRON_TAB(fname)); 116 117 process_crontab(fname, fname, tabname, 118 &statbuf, &new_db, old_db); 119 } 120 closedir(dir); 121 122 /* if we don't do this, then when our children eventually call 123 * getpwnam() in do_command.c's child_process to verify MAILTO=, 124 * they will screw us up (and v-v). 125 */ 126 endpwent(); 127 128 /* whatever's left in the old database is now junk. 129 */ 130 Debug(DLOAD, ("unlinking old database:\n")) 131 for (u = old_db->head; u != NULL; u = nu) { 132 Debug(DLOAD, ("\t%s\n", u->name)) 133 nu = u->next; 134 unlink_user(old_db, u); 135 free_user(u); 136 } 137 138 /* overwrite the database control block with the new one. 139 */ 140 *old_db = new_db; 141 Debug(DLOAD, ("load_database is done\n")) 142 } 143 144 145 void 146 link_user(cron_db *db, user *u) 147 { 148 if (db->head == NULL) 149 db->head = u; 150 if (db->tail) 151 db->tail->next = u; 152 u->prev = db->tail; 153 u->next = NULL; 154 db->tail = u; 155 } 156 157 158 void 159 unlink_user(cron_db *db, user *u) 160 { 161 if (u->prev == NULL) 162 db->head = u->next; 163 else 164 u->prev->next = u->next; 165 166 if (u->next == NULL) 167 db->tail = u->prev; 168 else 169 u->next->prev = u->prev; 170 } 171 172 173 user * 174 find_user(cron_db *db, char *name) 175 { 176 char *env_get(); 177 user *u; 178 179 for (u = db->head; u != NULL; u = u->next) 180 if (!strcmp(u->name, name)) 181 break; 182 return u; 183 } 184 185 186 static void 187 process_crontab(char *uname, char *fname, char *tabname, struct stat *statbuf, 188 cron_db *new_db, cron_db *old_db) 189 { 190 struct passwd *pw = NULL; 191 int crontab_fd = OK - 1; 192 user *u; 193 194 if (strcmp(fname, "*system*") && !(pw = getpwnam(uname))) { 195 /* file doesn't have a user in passwd file. 196 */ 197 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 198 goto next_crontab; 199 } 200 201 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 202 /* crontab not accessible? 203 */ 204 log_it(fname, getpid(), "CAN'T OPEN", tabname); 205 goto next_crontab; 206 } 207 208 if (fstat(crontab_fd, statbuf) < OK) { 209 log_it(fname, getpid(), "FSTAT FAILED", tabname); 210 goto next_crontab; 211 } 212 213 Debug(DLOAD, ("\t%s:", fname)) 214 u = find_user(old_db, fname); 215 if (u != NULL) { 216 /* if crontab has not changed since we last read it 217 * in, then we can just use our existing entry. 218 */ 219 if (u->mtime == statbuf->st_mtime) { 220 Debug(DLOAD, (" [no change, using old data]")) 221 unlink_user(old_db, u); 222 link_user(new_db, u); 223 goto next_crontab; 224 } 225 226 /* before we fall through to the code that will reload 227 * the user, let's deallocate and unlink the user in 228 * the old database. This is more a point of memory 229 * efficiency than anything else, since all leftover 230 * users will be deleted from the old database when 231 * we finish with the crontab... 232 */ 233 Debug(DLOAD, (" [delete old data]")) 234 unlink_user(old_db, u); 235 free_user(u); 236 log_it(fname, getpid(), "RELOAD", tabname); 237 } 238 u = load_user(crontab_fd, pw, fname); 239 if (u != NULL) { 240 u->mtime = statbuf->st_mtime; 241 link_user(new_db, u); 242 } 243 244 next_crontab: 245 if (crontab_fd >= OK) { 246 Debug(DLOAD, (" [done]\n")) 247 close(crontab_fd); 248 } 249 } 250