From: Tomas Mraz <tmraz@fedoraproject.org>
Date: Tue, 21 Jun 2011 18:26:38 +0200
Subject: Check orphaned crontabs for adoption.

Change the default behaviour of permanently ignoring crontabs with an invalid
owner (ie, getpwnam() fails) to checking for adoption every time cron wakes up.
This makes more sense as nowadays such failures are often traced back to
temporary issues, especially in the context of LDAP lookups and name-caching
daemons.

Bug-Debian: https://bugs.debian.org/634926
Bug-Ubuntu: https://bugs.launchpad.net/bugs/27520
Origin: https://git.fedorahosted.org/cgit/cronie.git/commit/?id=8b407876f276f96914111bd9954f21f627db7b11
Last-Update: 2016-01-15
---
 cron.c     |  1 +
 cron.h     | 10 +++++++-
 database.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 90 insertions(+), 3 deletions(-)

diff --git a/cron.c b/cron.c
index 84b19e6..673134a 100644
--- a/cron.c
+++ b/cron.c
@@ -171,6 +171,7 @@ main(argc, argv)
 		} while (clockTime == timeRunning);
 		timeRunning = clockTime;
 
+		check_orphans(&database);
 		load_database(&database);
 
 		/*
diff --git a/cron.h b/cron.h
index 6c866a4..94b8e04 100644
--- a/cron.h
+++ b/cron.h
@@ -216,6 +216,13 @@ typedef	struct _cron_db {
 	time_t		sysd_mtime;     /* last modtime on system crondir */
 } cron_db;
 
+typedef struct _orphan {
+	struct _orphan  *next;          /* link */
+	char	*uname;
+	char	*fname;
+	char	*tabname;
+} orphan;
+
 void		set_cron_uid __P((void)),
 		set_cron_cwd __P((void)),
 		load_database __P((cron_db *)),
@@ -232,7 +239,8 @@ void		set_cron_uid __P((void)),
 		acquire_daemonlock __P((int)),
 		skip_comments __P((FILE *)),
 		log_it __P((char *, int, char *, char *)),
-		log_close __P((void));
+		log_close __P((void)),
+		check_orphans __P((cron_db *));
 
 int		job_runqueue __P((void)),
 		set_debug_flags __P((char *)),
diff --git a/database.c b/database.c
index f16be38..b1dc7d5 100644
--- a/database.c
+++ b/database.c
@@ -53,6 +53,9 @@ static user *get_next_system_crontab __P((user *));
 
 void force_rescan_user(cron_db *old_db, cron_db *new_db, const char *fname, time_t old_mtime);
 
+static void add_orphan(const char *uname, const char *fname, const char *tabname);
+static void free_orphan(orphan *o);
+
 void
 load_database(old_db)
 	cron_db		*old_db;
@@ -311,7 +314,7 @@ process_crontab(uname, fname, tabname, statbuf, new_db, old_db)
 {
 	struct passwd	*pw = NULL;
 	int		crontab_fd = OK - 1;
-	user		*u;
+	user		*u = NULL;
 
 	/* If the name begins with *system*, don't worry about password -
 	 it's part of the system crontab */
@@ -321,6 +324,7 @@ process_crontab(uname, fname, tabname, statbuf, new_db, old_db)
 		if (strncmp(fname, "tmp.", 4)) {
 			/* don't log these temporary files */
 			log_it(fname, getpid(), "ORPHAN", "no passwd entry");
+			add_orphan(uname, fname, tabname);
 		}
 		goto next_crontab;
 	}
@@ -444,7 +448,10 @@ process_crontab(uname, fname, tabname, statbuf, new_db, old_db)
          * 1), but this is all we've got.
          */
 	Debug(DLOAD, ("\t%s:", fname))
-	u = find_user(old_db, fname);
+
+	if (old_db != NULL)
+		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.
@@ -580,3 +587,74 @@ force_rescan_user(cron_db *old_db, cron_db *new_db, const char *fname, time_t ol
 	Debug(DLOAD, ("\t%s: [added empty placeholder to force rescan]\n", fname))
 	link_user(new_db, u);
 }
+
+/* This fix was taken from Fedora cronie */
+static orphan *orphans;
+
+static void
+free_orphan(orphan *o) {
+	free(o->tabname);
+	free(o->fname);
+	free(o->uname);
+	free(o);
+}
+
+void
+check_orphans(cron_db *db) {
+	orphan *prev_orphan = NULL;
+	orphan *o = orphans;
+	struct stat statbuf;
+
+	while (o != NULL) {
+		if (getpwnam(o->uname) != NULL) {
+			orphan *next = o->next;
+
+			if (prev_orphan == NULL) {
+				orphans = next;
+			} else {
+				prev_orphan->next = next;
+			}
+
+			process_crontab(o->uname, o->fname, o->tabname,
+				&statbuf, db, NULL);
+
+			/* process_crontab could have added a new orphan */
+			if (prev_orphan == NULL && orphans != next) {
+				prev_orphan = orphans;
+			}
+			free_orphan(o);
+			o = next;
+		} else {
+			prev_orphan = o;
+			o = o->next;
+		}
+	}
+}
+
+static void
+add_orphan(const char *uname, const char *fname, const char *tabname) {
+	orphan *o;
+
+	o = calloc(1, sizeof(*o));
+	if (o == NULL)
+		return;
+
+	if (uname)
+		if ((o->uname=strdup(uname)) == NULL)
+			goto cleanup;
+
+	if (fname)
+		if ((o->fname=strdup(fname)) == NULL)
+			goto cleanup;
+
+	if (tabname)
+		if ((o->tabname=strdup(tabname)) == NULL)
+			goto cleanup;
+
+	o->next = orphans;
+	orphans = o;
+	return;
+
+cleanup:
+        free_orphan(o);
+}