Hold lock on NEXTJOB record for a very short time. Jerry needs to add code

to make this rebust w.r.t. stored devicemodes.
Jeremy.
(This used to be commit f93a008f09acda2ddaff9857f2fe0c86948539d1)

1 files changed, 52 insertions, 29 deletions

diff --git a/source3/printing/printing.c b/source3/printing/printing.c
index 208da5b78b..0344d44d61 100644
--- a/source3/printing/printing.c
+++ b/source3/printing/printing.c
@@ -382,9 +382,13 @@ static uint32 sysjob_to_jobid_value;
 static int unixjob_traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA key,
 			       TDB_DATA data, void *state)
 {
-	struct printjob *pjob = (struct printjob *)data.dptr;
+	struct printjob *pjob;
 	int *sysjob = (int *)state;
 
+	if (!data.dptr || data.dsize == 0)
+		return 0;
+
+	pjob = (struct printjob *)data.dptr;
 	if (key.dsize != sizeof(uint32))
 		return 0;
 
@@ -1408,6 +1412,7 @@ uint32 print_job_start(struct current_user *user, int snum, char *jobname, NT_DE
 	int njobs = 0;
 	const char *printername = lp_const_servicename(snum);
 	struct tdb_print_db *pdb = get_print_db_byname(printername);
+	BOOL pdb_locked = False;
 
 	errno = 0;
 
@@ -1457,37 +1462,15 @@ uint32 print_job_start(struct current_user *user, int snum, char *jobname, NT_DE
 		return (uint32)-1;
 	}
 
-	/* create the database entry */
-	
-	ZERO_STRUCT(pjob);
-	
-	pjob.pid = local_pid;
-	pjob.sysjob = -1;
-	pjob.fd = -1;
-	pjob.starttime = time(NULL);
-	pjob.status = LPQ_SPOOLING;
-	pjob.size = 0;
-	pjob.spooled = False;
-	pjob.smbjob = True;
-	pjob.nt_devmode = nt_devmode;
-	
-	fstrcpy(pjob.jobname, jobname);
-
-	if ((vuser = get_valid_user_struct(user->vuid)) != NULL) {
-		fstrcpy(pjob.user, vuser->user.smb_name);
-	} else {
-		fstrcpy(pjob.user, uidtoname(user->uid));
-	}
-
-	fstrcpy(pjob.queuename, lp_const_servicename(snum));
-
-	/* lock the database */
+	/* Lock the database */
 	if (tdb_lock_bystring(pdb->tdb, "INFO/nextjob") == -1) {
 		DEBUG(0,("print_job_start: failed to lock printing database %s\n", printername ));
 		release_print_db(pdb);
 		return (uint32)-1;
 	}
 
+	pdb_locked = True;
+
 	next_jobid = tdb_fetch_int32(pdb->tdb, "INFO/nextjob");
 	if (next_jobid == -1)
 		next_jobid = 1;
@@ -1496,13 +1479,27 @@ uint32 print_job_start(struct current_user *user, int snum, char *jobname, NT_DE
 		if (!print_job_exists(snum, jobid))
 			break;
 	}
-	if (jobid == next_jobid || !pjob_store(snum, jobid, &pjob)) {
-		DEBUG(3, ("print_job_start: either jobid (%d)==next_jobid(%d) or pjob_store failed.\n",
+				
+	if (jobid == next_jobid) {
+		DEBUG(3, ("print_job_start: jobid (%d)==next_jobid(%d).\n",
 				jobid, next_jobid ));
 		jobid = -1;
 		goto fail;
 	}
 
+	/* Store a dummy placeholder. This must be quick as we have the lock. */
+	{
+		TDB_DATA dum;
+		dum.dptr = NULL;
+		dum.dsize = 0;
+		if (tdb_store(pdb->tdb, print_key(jobid), dum, TDB_INSERT) == -1) {
+			DEBUG(3, ("print_job_start: jobid (%d) failed to store placeholder.\n",
+				jobid ));
+			jobid = -1;
+			goto fail;
+		}
+	}
+
 	if (tdb_store_int32(pdb->tdb, "INFO/nextjob", jobid)==-1) {
 		DEBUG(3, ("print_job_start: failed to store INFO/nextjob.\n"));
 		jobid = -1;
@@ -1511,6 +1508,31 @@ uint32 print_job_start(struct current_user *user, int snum, char *jobname, NT_DE
 
 	/* We've finished with the INFO/nextjob lock. */
 	tdb_unlock_bystring(pdb->tdb, "INFO/nextjob");
+	pdb_locked = False;
+
+	/* create the database entry */
+	
+	ZERO_STRUCT(pjob);
+	
+	pjob.pid = local_pid;
+	pjob.sysjob = -1;
+	pjob.fd = -1;
+	pjob.starttime = time(NULL);
+	pjob.status = LPQ_SPOOLING;
+	pjob.size = 0;
+	pjob.spooled = False;
+	pjob.smbjob = True;
+	pjob.nt_devmode = nt_devmode;
+	
+	fstrcpy(pjob.jobname, jobname);
+
+	if ((vuser = get_valid_user_struct(user->vuid)) != NULL) {
+		fstrcpy(pjob.user, vuser->user.smb_name);
+	} else {
+		fstrcpy(pjob.user, uidtoname(user->uid));
+	}
+
+	fstrcpy(pjob.queuename, lp_const_servicename(snum));
 
 	/* we have a job entry - now create the spool file */
 	slprintf(pjob.filename, sizeof(pjob.filename)-1, "%s/%s%.8u.XXXXXX", 
@@ -1551,7 +1573,8 @@ to open spool file %s.\n", pjob.filename));
 	if (jobid != -1)
 		pjob_delete(snum, jobid);
 
-	tdb_unlock_bystring(pdb->tdb, "INFO/nextjob");
+	if (pdb_locked)
+		tdb_unlock_bystring(pdb->tdb, "INFO/nextjob");
 	release_print_db(pdb);
 
 	DEBUG(3, ("print_job_start: returning fail. Error = %s\n", strerror(errno) ));