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samba-mirror/source3/printing/printer_list.h
David Disseldorp 1e83435eac printing: traverse_read the printer list for share updates
The printcap update procedure involves the background printer process
obtaining the printcap information from the printing backend, writing
this to printer_list.tdb, and then notifying all smbd processes of the
new list. The processes then all attempt to simultaneously traverse
printer_list.tdb, in order to update their local share lists.

With a large number of printers, and a large number of per-client smbd
processes, this traversal results in significant lock contention, mostly
due to the fact that the traversal is unnecessarily done with an
exclusive (write) lock on the printer_list.tdb database.

This commit changes the share update code path to perform a read-only
traversal.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10652

Reported-by: Alex K <korobkin+samba@gmail.com>
Reported-by: Franz Pförtsch <franz.pfoertsch@brose.com>
Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
2014-08-08 14:10:38 +02:00

106 lines
3.4 KiB
C

/*
Unix SMB/CIFS implementation.
Share Database of available printers.
Copyright (C) Simo Sorce 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _PRINTER_LIST_H_
#define _PRINTER_LIST_H_
bool printer_list_parent_init(void);
/**
* @brief Get the comment and the last refresh time from the printer list
* database.
*
* @param[in] mem_ctx The talloc memory context to use.
*
* @param[in] name The printer name to lookup.
*
* @param[out] comment A pointer to store the comment of the printer.
*
* @param[out] location A pointer to store the location of the printer.
*
* @param[out] last_refresh A pointer to store the last refresh time of the
* printer.
*
* @return NT_STATUS_OK on success, a correspoining NTSTATUS error
* code on a failure.
*/
NTSTATUS printer_list_get_printer(TALLOC_CTX *mem_ctx,
const char *name,
const char **comment,
const char **location,
time_t *last_refresh);
/**
* @brief Add a printer to the printer list database.
*
* @param[in] mem_ctx The talloc memory context to use.
*
* @param[in] name The printer name to store in the db.
*
* @param[in] comment The comment to store in the db.
*
* @param[in] location The location to store in the db.
*
* @param[in] last_refresh The last refresh time of the printer to store in
* the db.
*
* @return NT_STATUS_OK on success, a correspoining NTSTATUS error
* code on a failure.
*/
NTSTATUS printer_list_set_printer(TALLOC_CTX *mem_ctx,
const char *name,
const char *comment,
const char *location,
time_t last_refresh);
/**
* @brief Get the time of the last refresh of the printer database.
*
* @param[out] last_refresh The last refresh time in the db.
*
* @return NT_STATUS_OK on success, a correspoining NTSTATUS error
* code on a failure.
*/
NTSTATUS printer_list_get_last_refresh(time_t *last_refresh);
/**
* @brief Mark the database as reloaded.
*
* This sets the last refresh time to the current time. You can get the last
* reload/refresh time of the database with printer_list_get_last_refresh().
*
* @return NT_STATUS_OK on success, a correspoining NTSTATUS error
* code on a failure.
*/
NTSTATUS printer_list_mark_reload(void);
/**
* @brief Cleanup old entries in the database.
*
* Entries older than the last refresh times will be deleted.
*
* @return NT_STATUS_OK on success, a correspoining NTSTATUS error
* code on a failure.
*/
NTSTATUS printer_list_clean_old(void);
NTSTATUS printer_list_read_run_fn(void (*fn)(const char *, const char *, const char *, void *),
void *private_data);
#endif /* _PRINTER_LIST_H_ */