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 1.6 2005/08/08 18:36:28 joerg 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[NAME_MAX + 1], tabname[NAME_MAX + 1]; 103 104 /* avoid file names beginning with ".". this is good 105 * because we would otherwise waste two guaranteed calls 106 * to getpwnam() for . and .., and also because user names 107 * starting with a period are just too nasty to consider. 108 */ 109 if (dp->d_name[0] == '.') 110 continue; 111 112 strlcpy(fname, dp->d_name, sizeof(fname)); 113 snprintf(tabname, sizeof tabname, CRON_TAB(fname)); 114 115 process_crontab(fname, fname, tabname, 116 &statbuf, &new_db, old_db); 117 } 118 closedir(dir); 119 120 /* if we don't do this, then when our children eventually call 121 * getpwnam() in do_command.c's child_process to verify MAILTO=, 122 * they will screw us up (and v-v). 123 */ 124 endpwent(); 125 126 /* whatever's left in the old database is now junk. 127 */ 128 Debug(DLOAD, ("unlinking old database:\n")) 129 for (u = old_db->head; u != NULL; u = nu) { 130 Debug(DLOAD, ("\t%s\n", u->name)) 131 nu = u->next; 132 unlink_user(old_db, u); 133 free_user(u); 134 } 135 136 /* overwrite the database control block with the new one. 137 */ 138 *old_db = new_db; 139 Debug(DLOAD, ("load_database is done\n")) 140 } 141 142 143 void 144 link_user(cron_db *db, user *u) 145 { 146 if (db->head == NULL) 147 db->head = u; 148 if (db->tail) 149 db->tail->next = u; 150 u->prev = db->tail; 151 u->next = NULL; 152 db->tail = u; 153 } 154 155 156 void 157 unlink_user(cron_db *db, user *u) 158 { 159 if (u->prev == NULL) 160 db->head = u->next; 161 else 162 u->prev->next = u->next; 163 164 if (u->next == NULL) 165 db->tail = u->prev; 166 else 167 u->next->prev = u->prev; 168 } 169 170 171 user * 172 find_user(cron_db *db, char *name) 173 { 174 char *env_get(); 175 user *u; 176 177 for (u = db->head; u != NULL; u = u->next) 178 if (!strcmp(u->name, name)) 179 break; 180 return u; 181 } 182 183 184 static void 185 process_crontab(char *uname, char *fname, char *tabname, struct stat *statbuf, 186 cron_db *new_db, cron_db *old_db) 187 { 188 struct passwd *pw = NULL; 189 int crontab_fd = OK - 1; 190 user *u; 191 192 if (strcmp(fname, "*system*") && !(pw = getpwnam(uname))) { 193 /* file doesn't have a user in passwd file. 194 */ 195 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 196 goto next_crontab; 197 } 198 199 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 200 /* crontab not accessible? 201 */ 202 log_it(fname, getpid(), "CAN'T OPEN", tabname); 203 goto next_crontab; 204 } 205 206 if (fstat(crontab_fd, statbuf) < OK) { 207 log_it(fname, getpid(), "FSTAT FAILED", tabname); 208 goto next_crontab; 209 } 210 211 Debug(DLOAD, ("\t%s:", fname)) 212 u = find_user(old_db, fname); 213 if (u != NULL) { 214 /* if crontab has not changed since we last read it 215 * in, then we can just use our existing entry. 216 */ 217 if (u->mtime == statbuf->st_mtime) { 218 Debug(DLOAD, (" [no change, using old data]")) 219 unlink_user(old_db, u); 220 link_user(new_db, u); 221 goto next_crontab; 222 } 223 224 /* before we fall through to the code that will reload 225 * the user, let's deallocate and unlink the user in 226 * the old database. This is more a point of memory 227 * efficiency than anything else, since all leftover 228 * users will be deleted from the old database when 229 * we finish with the crontab... 230 */ 231 Debug(DLOAD, (" [delete old data]")) 232 unlink_user(old_db, u); 233 free_user(u); 234 log_it(fname, getpid(), "RELOAD", tabname); 235 } 236 u = load_user(crontab_fd, pw, fname); 237 if (u != NULL) { 238 u->mtime = statbuf->st_mtime; 239 link_user(new_db, u); 240 } 241 242 next_crontab: 243 if (crontab_fd >= OK) { 244 Debug(DLOAD, (" [done]\n")) 245 close(crontab_fd); 246 } 247 } 248