/* Copyright 1988,1990,1993,1994 by Paul Vixie * All rights reserved * * Distribute freely, except: don't remove my name from the source or * documentation (don't take credit for my work), mark your changes (don't * get me blamed for your possible bugs), don't alter or remove this * notice. May be sold if buildable source is provided to buyer. No * warrantee of any kind, express or implied, is included with this * software; use at your own risk, responsibility for damages (if any) to * anyone resulting from the use of this software rests entirely with the * user. * * Send bug reports, bug fixes, enhancements, requests, flames, etc., and * I'll try to keep a version up to date. I can be reached as follows: * Paul Vixie uunet!decwrl!vixie!paul */ #if !defined(lint) && !defined(LINT) static char rcsid[] = "$Id: database.c,v 2.8 1994/01/15 20:43:43 vixie Exp $"; #endif /* vix 26jan87 [RCS has the log] */ #include "cron.h" #include #include #include #define TMAX(a,b) ((a)>(b)?(a):(b)) static void process_crontab __P((char *, char *, char *, struct stat *, cron_db *, cron_db *)); void load_database(old_db) cron_db *old_db; { DIR *dir; struct stat statbuf; struct stat syscron_stat; register DIR_T *dp; cron_db new_db; user *u, *nu; Debug(DLOAD, ("[%d] load_database()\n", getpid())) /* before we start loading any data, do a stat on SPOOL_DIR * so that if anything changes as of this moment (i.e., before we've * cached any of the database), we'll see the changes next time. */ if (stat(SPOOL_DIR, &statbuf) < OK) { log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); (void) exit(ERROR_EXIT); } /* track system crontab file */ if (stat(SYSCRONTAB, &syscron_stat) < OK) syscron_stat.st_mtime = 0; /* if spooldir's mtime has not changed, we don't need to fiddle with * the database. * * Note that old_db->mtime is initialized to 0 in main(), and * so is guaranteed to be different than the stat() mtime the first * time this function is called. */ if (old_db->mtime == TMAX(statbuf.st_mtime, syscron_stat.st_mtime)) { Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", getpid())) return; } /* something's different. make a new database, moving unchanged * elements from the old database, reloading elements that have * actually changed. Whatever is left in the old database when * we're done is chaff -- crontabs that disappeared. */ new_db.mtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); new_db.head = new_db.tail = NULL; if (syscron_stat.st_mtime) { process_crontab("root", "*system*", SYSCRONTAB, &syscron_stat, &new_db, old_db); } /* we used to keep this dir open all the time, for the sake of * efficiency. however, we need to close it in every fork, and * we fork a lot more often than the mtime of the dir changes. */ if (!(dir = opendir(SPOOL_DIR))) { log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); (void) exit(ERROR_EXIT); } while (NULL != (dp = readdir(dir))) { char fname[MAXNAMLEN+1], tabname[MAXNAMLEN+1]; /* avoid file names beginning with ".". this is good * because we would otherwise waste two guaranteed calls * to getpwnam() for . and .., and also because user names * starting with a period are just too nasty to consider. */ if (dp->d_name[0] == '.') continue; (void) strcpy(fname, dp->d_name); sprintf(tabname, CRON_TAB(fname)); process_crontab(fname, fname, tabname, &statbuf, &new_db, old_db); } closedir(dir); /* if we don't do this, then when our children eventually call * getpwnam() in do_command.c's child_process to verify MAILTO=, * they will screw us up (and v-v). */ endpwent(); /* whatever's left in the old database is now junk. */ Debug(DLOAD, ("unlinking old database:\n")) for (u = old_db->head; u != NULL; u = nu) { Debug(DLOAD, ("\t%s\n", u->name)) nu = u->next; unlink_user(old_db, u); free_user(u); } /* overwrite the database control block with the new one. */ *old_db = new_db; Debug(DLOAD, ("load_database is done\n")) } void link_user(db, u) register cron_db *db; register user *u; { if (db->head == NULL) db->head = u; if (db->tail) db->tail->next = u; u->prev = db->tail; u->next = NULL; db->tail = u; } void unlink_user(db, u) register cron_db *db; register user *u; { if (u->prev == NULL) db->head = u->next; else u->prev->next = u->next; if (u->next == NULL) db->tail = u->prev; else u->next->prev = u->prev; } user * find_user(db, name) cron_db *db; register char *name; { char *env_get(); register user *u; for (u = db->head; u != NULL; u = u->next) if (!strcmp(u->name, name)) break; return u; } static void process_crontab(uname, fname, tabname, statbuf, new_db, old_db) char *uname; char *fname; char *tabname; struct stat *statbuf; cron_db *new_db; cron_db *old_db; { struct passwd *pw = NULL; int crontab_fd = OK - 1; register user *u; if (strcmp(fname, "*system*") && !(pw = getpwnam(uname))) { /* file doesn't have a user in passwd file. */ log_it(fname, getpid(), "ORPHAN", "no passwd entry"); goto next_crontab; } if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { /* crontab not accessible? */ log_it(fname, getpid(), "CAN'T OPEN", tabname); goto next_crontab; } if (fstat(crontab_fd, statbuf) < OK) { log_it(fname, getpid(), "FSTAT FAILED", tabname); goto next_crontab; } Debug(DLOAD, ("\t%s:", fname)) u = find_user(old_db, fname); if (u != NULL) { /* if crontab has not changed since we last read it * in, then we can just use our existing entry. */ if (u->mtime == statbuf->st_mtime) { Debug(DLOAD, (" [no change, using old data]")) unlink_user(old_db, u); link_user(new_db, u); goto next_crontab; } /* before we fall through to the code that will reload * the user, let's deallocate and unlink the user in * the old database. This is more a point of memory * efficiency than anything else, since all leftover * users will be deleted from the old database when * we finish with the crontab... */ Debug(DLOAD, (" [delete old data]")) unlink_user(old_db, u); free_user(u); log_it(fname, getpid(), "RELOAD", tabname); } u = load_user(crontab_fd, pw, fname); if (u != NULL) { u->mtime = statbuf->st_mtime; link_user(new_db, u); } next_crontab: if (crontab_fd >= OK) { Debug(DLOAD, (" [done]\n")) close(crontab_fd); } }