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head/usr.sbin/cron/cron/database.c
| Show All 39 Lines | |||||
| void | void | ||||
| load_database(old_db) | load_database(old_db) | ||||
| cron_db *old_db; | cron_db *old_db; | ||||
| { | { | ||||
| DIR *dir; | DIR *dir; | ||||
| struct stat statbuf; | struct stat statbuf; | ||||
| struct stat syscron_stat; | struct stat syscron_stat; | ||||
| time_t maxmtime; | |||||
| DIR_T *dp; | DIR_T *dp; | ||||
| cron_db new_db; | cron_db new_db; | ||||
| user *u, *nu; | user *u, *nu; | ||||
| struct { | |||||
| const char *name; | |||||
| struct stat st; | |||||
| } syscrontabs [] = { | |||||
| { SYSCRONTABS }, | |||||
| { LOCALSYSCRONTABS } | |||||
| }; | |||||
| int i; | |||||
| Debug(DLOAD, ("[%d] load_database()\n", getpid())) | Debug(DLOAD, ("[%d] load_database()\n", getpid())) | ||||
| /* before we start loading any data, do a stat on SPOOL_DIR | /* 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 | * 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. | * cached any of the database), we'll see the changes next time. | ||||
| */ | */ | ||||
| if (stat(SPOOL_DIR, &statbuf) < OK) { | if (stat(SPOOL_DIR, &statbuf) < OK) { | ||||
| log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); | log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR); | ||||
| (void) exit(ERROR_EXIT); | (void) exit(ERROR_EXIT); | ||||
| } | } | ||||
| /* track system crontab file | /* track system crontab file | ||||
| */ | */ | ||||
| if (stat(SYSCRONTAB, &syscron_stat) < OK) | if (stat(SYSCRONTAB, &syscron_stat) < OK) | ||||
| syscron_stat.st_mtime = 0; | syscron_stat.st_mtime = 0; | ||||
| maxmtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); | |||||
| for (i = 0; i < nitems(syscrontabs); i++) { | |||||
| if (stat(syscrontabs[i].name, &syscrontabs[i].st) != -1) { | |||||
jilles: This means that modifying an existing file in /etc/cron.d is not detected. That is an uncommon… | |||||
baptAuthorUnsubmitted Not Done Inline ActionsThat is the same behaviour as how users crontabs are detected to have been modified. I find it pretty convenient :) might be inefficient if lots of cron files have been added any better idea? bapt: That is the same behaviour as how users crontabs are detected to have been modified. I find it… | |||||
knuUnsubmitted Not Done Inline ActionsThe cron(8) man page reads: "Note that the crontab(1) command updates the modification time of the spool directory whenever it changes a crontab." So for user crontabs it is transparent to users because they always edit their crontab via crontab(1). On the other hand there's no tool support for /etc/cron.d/*, so you have to manually edit a file in it just to find out crond will not reload it unless you touch /etc/cron.d by hand. I think we should follow Debian's cron which properly checks modification times of individual files in cron.d: https://anonscm.debian.org/cgit/pkg-cron/pkg-cron.git/tree/database.c?id=1215fdaddba158f32b10f0cc041e634505d50cb8#n118 knu: The cron(8) man page reads: "Note that the crontab(1) command updates the modification time of… | |||||
| maxmtime = TMAX(syscrontabs[i].st.st_mtime, maxmtime); | |||||
| } else { | |||||
| syscrontabs[i].st.st_mtime = 0; | |||||
| } | |||||
| } | |||||
| /* if spooldir's mtime has not changed, we don't need to fiddle with | /* if spooldir's mtime has not changed, we don't need to fiddle with | ||||
| * the database. | * the database. | ||||
| * | * | ||||
| * Note that old_db->mtime is initialized to 0 in main(), and | * Note that old_db->mtime is initialized to 0 in main(), and | ||||
| * so is guaranteed to be different than the stat() mtime the first | * so is guaranteed to be different than the stat() mtime the first | ||||
| * time this function is called. | * time this function is called. | ||||
| */ | */ | ||||
| if (old_db->mtime == TMAX(statbuf.st_mtime, syscron_stat.st_mtime)) { | if (old_db->mtime == maxmtime) { | ||||
| Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", | Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", | ||||
| getpid())) | getpid())) | ||||
| return; | return; | ||||
| } | } | ||||
| /* something's different. make a new database, moving unchanged | /* something's different. make a new database, moving unchanged | ||||
| * elements from the old database, reloading elements that have | * elements from the old database, reloading elements that have | ||||
| * actually changed. Whatever is left in the old database when | * actually changed. Whatever is left in the old database when | ||||
| * we're done is chaff -- crontabs that disappeared. | * we're done is chaff -- crontabs that disappeared. | ||||
| */ | */ | ||||
| new_db.mtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime); | new_db.mtime = maxmtime; | ||||
| new_db.head = new_db.tail = NULL; | new_db.head = new_db.tail = NULL; | ||||
| if (syscron_stat.st_mtime) { | if (syscron_stat.st_mtime) { | ||||
| process_crontab("root", SYS_NAME, | process_crontab("root", SYS_NAME, | ||||
| SYSCRONTAB, &syscron_stat, | SYSCRONTAB, &syscron_stat, | ||||
| &new_db, old_db); | &new_db, old_db); | ||||
| } | |||||
| for (i = 0; i < nitems(syscrontabs); i++) { | |||||
| char tabname[MAXPATHLEN]; | |||||
| if (syscrontabs[i].st.st_mtime == 0) | |||||
| continue; | |||||
| if (!(dir = opendir(syscrontabs[i].name))) { | |||||
| log_it("CRON", getpid(), "OPENDIR FAILED", | |||||
| syscrontabs[i].name); | |||||
| (void) exit(ERROR_EXIT); | |||||
| } | |||||
| while (NULL != (dp = readdir(dir))) { | |||||
| if (dp->d_name[0] == '.') | |||||
| continue; | |||||
| if (dp->d_type != DT_REG) | |||||
jillesUnsubmitted Done Inline ActionsWe have filesystems that return DT_UNKNOWN (such as NFS with default options), in which case an fstatat is required. This check also prevents following symlinks in /etc/cron.d which Debian's cron allows. jilles: We have filesystems that return DT_UNKNOWN (such as NFS with default options), in which case an… | |||||
baptAuthorUnsubmitted Not Done Inline ActionsFixed thanks bapt: Fixed thanks | |||||
| continue; | |||||
| snprintf(tabname, sizeof(tabname), "%s/%s", | |||||
| syscrontabs[i].name, dp->d_name); | |||||
| process_crontab("root", SYS_NAME, tabname, | |||||
knuUnsubmitted Not Done Inline ActionsLoading all crontabs into a single namespace that is the same as /etc/crontab ("root") means environment variable settings defined in a file will be overwritten by those in another. So, one crontab file installed by a package may affect system jobs, which does not seem great to me. Debian seems to allocate separate namespaces for each cron.d file by using the filenames: https://anonscm.debian.org/cgit/pkg-cron/pkg-cron.git/tree/database.c?id=1215fdaddba158f32b10f0cc041e634505d50cb8#n247 knu: Loading all crontabs into a single namespace that is the same as /etc/crontab ("root") means… | |||||
| &syscrontabs[i].st, &new_db, old_db); | |||||
| } | |||||
| closedir(dir); | |||||
| } | } | ||||
| /* we used to keep this dir open all the time, for the sake of | /* 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 | * efficiency. however, we need to close it in every fork, and | ||||
| * we fork a lot more often than the mtime of the dir changes. | * we fork a lot more often than the mtime of the dir changes. | ||||
| */ | */ | ||||
| if (!(dir = opendir(SPOOL_DIR))) { | if (!(dir = opendir(SPOOL_DIR))) { | ||||
| log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); | log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); | ||||
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This means that modifying an existing file in /etc/cron.d is not detected. That is an uncommon thing to do.