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authorJeremy Allison <jra@samba.org>2002-08-27 20:15:35 +0000
committerJeremy Allison <jra@samba.org>2002-08-27 20:15:35 +0000
commit16413f2d9de850dcfea135fd5ceb4cd30a115ffa (patch)
treea82d397797e43882b190d61983e80440745420f1 /source3
parent4896421e30c15fa9d313c319e23275bb48e333fc (diff)
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Allow us to "lock" printer tdb entries in memory to stop them being
re-used as cache. Jeremy. (This used to be commit 6f901e479dd7a0b9d1395aad5b8ef028c0514fec)
Diffstat (limited to 'source3')
-rw-r--r--source3/printing/printing.c79
1 files changed, 61 insertions, 18 deletions
diff --git a/source3/printing/printing.c b/source3/printing/printing.c
index cb689c05d6..61c3282196 100644
--- a/source3/printing/printing.c
+++ b/source3/printing/printing.c
@@ -132,11 +132,13 @@ static pid_t local_pid;
static int get_queue_status(int, print_status_struct *);
+/* There can be this many printing tdb's open, plus any locked ones. */
#define MAX_PRINT_DBS_OPEN 1
struct tdb_print_db {
struct tdb_print_db *next, *prev;
TDB_CONTEXT *tdb;
+ int locked;
fstring printer_name;
};
@@ -149,7 +151,7 @@ static struct tdb_print_db *print_db_head;
static struct tdb_print_db *get_print_db_byname(const char *printername)
{
- struct tdb_print_db *p, *last_entry;
+ struct tdb_print_db *p = NULL, *last_entry = NULL;
int num_open = 0;
pstring printdb_path;
@@ -161,20 +163,28 @@ static struct tdb_print_db *get_print_db_byname(const char *printername)
num_open++;
last_entry = p;
}
+
/* Not found. */
if (num_open >= MAX_PRINT_DBS_OPEN) {
- /* Recycle the last entry. */
+ /* Try and recycle the last entry. */
DLIST_PROMOTE(print_db_head, last_entry);
- if (print_db_head->tdb) {
- if (tdb_close(print_db_head->tdb)) {
- DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
- print_db_head->printer_name ));
- return NULL;
+
+ for (p = print_db_head; p; p = p->next) {
+ if (p->locked)
+ continue;
+ if (p->tdb) {
+ if (tdb_close(print_db_head->tdb)) {
+ DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
+ print_db_head->printer_name ));
+ return NULL;
+ }
+ ZERO_STRUCTP(p);
+ DLIST_PROMOTE(print_db_head, p);
}
}
- p = print_db_head;
- ZERO_STRUCTP(p);
- } else {
+ }
+
+ if (!p) {
/* Create one. */
p = (struct tdb_print_db *)malloc(sizeof(struct tdb_print_db));
if (!p) {
@@ -205,6 +215,30 @@ static struct tdb_print_db *get_print_db_byname(const char *printername)
}
/****************************************************************************
+ Lock a pdb entry by string.
+****************************************************************************/
+
+static int pdb_entry_lock(struct tdb_print_db *pdb, char *key)
+{
+ if (pdb->locked == 0) {
+ if (tdb_lock_bystring(pdb->tdb, key) == -1)
+ return -1;
+ }
+ pdb->locked++;
+}
+
+/****************************************************************************
+ Unlock a pdb entry by string.
+****************************************************************************/
+
+static void pdb_entry_unlock(struct tdb_print_db *pdb, char *key)
+{
+ pdb->locked--;
+ if (pdb->locked == 0)
+ tdb_unlock_bystring(pdb->tdb, key);
+}
+
+/****************************************************************************
Initialise the printing backend. Called once at startup.
Does not survive a fork
****************************************************************************/
@@ -235,12 +269,15 @@ BOOL print_backend_init(void)
pdb = get_print_db_byname(lp_const_servicename(snum));
if (!pdb)
continue;
- tdb_lock_bystring(pdb->tdb, sversion);
+ if (pdb_entry_lock(pdb, sversion) == -1) {
+ DEBUG(0,("print_backend_init: Failed to open printer %s database\n", lp_const_servicename(snum) ));
+ return False;
+ }
if (tdb_fetch_int32(pdb->tdb, sversion) != PRINT_DATABASE_VERSION) {
tdb_traverse(pdb->tdb, tdb_traverse_delete_fn, NULL);
tdb_store_int32(pdb->tdb, sversion, PRINT_DATABASE_VERSION);
}
- tdb_unlock_bystring(pdb->tdb, sversion);
+ pdb_entry_unlock(pdb, sversion);
}
/* select the appropriate printing interface... */
@@ -746,7 +783,10 @@ static void print_queue_update(int snum)
/* Lock the queue for the database update */
slprintf(keystr, sizeof(keystr) - 1, "LOCK/%s", printer_name);
- tdb_lock_bystring(pdb->tdb, keystr);
+ if (pdb_entry_lock(pdb, keystr) == -1) {
+ DEBUG(0,("print_queue_update: Failed to lock printer %s database\n", printer_name));
+ return;
+ }
/*
* Ensure that no one else got in here.
@@ -758,7 +798,7 @@ static void print_queue_update(int snum)
/*
* Someone else is doing the update, exit.
*/
- tdb_unlock_bystring(pdb->tdb, keystr);
+ pdb_entry_unlock(pdb, keystr);
return;
}
@@ -774,7 +814,7 @@ static void print_queue_update(int snum)
* the update.
*/
- tdb_unlock_bystring(pdb->tdb, keystr);
+ pdb_entry_unlock(pdb, keystr);
/*
* Update the cache time FIRST ! Stops others even
@@ -1335,7 +1375,10 @@ uint32 print_job_start(struct current_user *user, int snum, char *jobname)
fstrcpy(pjob.queuename, lp_const_servicename(snum));
/* lock the database */
- tdb_lock_bystring(pdb->tdb, "INFO/nextjob");
+ if (pdb_entry_lock(pdb, "INFO/nextjob") == -1) {
+ DEBUG(0,("print_job_start: failed to lock printing database %s\n", printername ));
+ return (uint32)-1;
+ }
next_jobid = tdb_fetch_int32(pdb->tdb, "INFO/nextjob");
if (next_jobid == -1)
@@ -1378,7 +1421,7 @@ to open spool file %s.\n", pjob.filename));
pjob_store(snum, jobid, &pjob);
- tdb_unlock_bystring(pdb->tdb, "INFO/nextjob");
+ pdb_entry_unlock(pdb, "INFO/nextjob");
/*
* If the printer is marked as postscript output a leading
@@ -1397,7 +1440,7 @@ to open spool file %s.\n", pjob.filename));
if (jobid != -1)
pjob_delete(snum, jobid);
- tdb_unlock_bystring(pdb->tdb, "INFO/nextjob");
+ pdb_entry_unlock(pdb, "INFO/nextjob");
DEBUG(3, ("print_job_start: returning fail. Error = %s\n", strerror(errno) ));
return -1;