1/*
2   Unix SMB/Netbios implementation.
3   Version 3.0
4   printing backend routines
5   Copyright (C) Andrew Tridgell 1992-2000
6   Copyright (C) Jeremy Allison 2002
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21*/
22
23#include "includes.h"
24#include "printing.h"
25
26static struct tdb_print_db *print_db_head;
27
28/****************************************************************************
29  Function to find or create the printer specific job tdb given a printername.
30  Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
31****************************************************************************/
32
33struct tdb_print_db *get_print_db_byname(const char *printername)
34{
35	struct tdb_print_db *p = NULL, *last_entry = NULL;
36	int num_open = 0;
37	pstring printdb_path;
38	BOOL done_become_root = False;
39
40	SMB_ASSERT(printername != NULL);
41
42	for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
43		/* Ensure the list terminates... JRA. */
44		SMB_ASSERT(p->next != print_db_head);
45
46		if (p->tdb && strequal(p->printer_name, printername)) {
47			DLIST_PROMOTE(print_db_head, p);
48			p->ref_count++;
49			return p;
50		}
51		num_open++;
52		last_entry = p;
53	}
54
55	/* Not found. */
56	if (num_open >= MAX_PRINT_DBS_OPEN) {
57		/* Try and recycle the last entry. */
58		if (print_db_head && last_entry) {
59			DLIST_PROMOTE(print_db_head, last_entry);
60		}
61
62		for (p = print_db_head; p; p = p->next) {
63			if (p->ref_count)
64				continue;
65			if (p->tdb) {
66				if (tdb_close(print_db_head->tdb)) {
67					DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
68								print_db_head->printer_name ));
69					return NULL;
70				}
71			}
72			p->tdb = NULL;
73			p->ref_count = 0;
74			memset(p->printer_name, '\0', sizeof(p->printer_name));
75			break;
76		}
77		if (p && print_db_head) {
78			DLIST_PROMOTE(print_db_head, p);
79			p = print_db_head;
80		}
81	}
82
83	if (!p)	{
84		/* Create one. */
85		p = SMB_MALLOC_P(struct tdb_print_db);
86		if (!p) {
87			DEBUG(0,("get_print_db: malloc fail !\n"));
88			return NULL;
89		}
90		ZERO_STRUCTP(p);
91		DLIST_ADD(print_db_head, p);
92	}
93
94	pstrcpy(printdb_path, lock_path("printing/"));
95	pstrcat(printdb_path, printername);
96	pstrcat(printdb_path, ".tdb");
97
98	if (geteuid() != 0) {
99		become_root();
100		done_become_root = True;
101	}
102
103	p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
104		0600);
105
106	if (done_become_root)
107		unbecome_root();
108
109	if (!p->tdb) {
110		DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
111					printdb_path ));
112		DLIST_REMOVE(print_db_head, p);
113		SAFE_FREE(p);
114		return NULL;
115	}
116	fstrcpy(p->printer_name, printername);
117	p->ref_count++;
118	return p;
119}
120
121/***************************************************************************
122 Remove a reference count.
123****************************************************************************/
124
125void release_print_db( struct tdb_print_db *pdb)
126{
127	pdb->ref_count--;
128	SMB_ASSERT(pdb->ref_count >= 0);
129}
130
131/***************************************************************************
132 Close all open print db entries.
133****************************************************************************/
134
135void close_all_print_db(void)
136{
137	struct tdb_print_db *p = NULL, *next_p = NULL;
138
139	for (p = print_db_head; p; p = next_p) {
140		next_p = p->next;
141
142		if (p->tdb)
143			tdb_close(p->tdb);
144		DLIST_REMOVE(print_db_head, p);
145		ZERO_STRUCTP(p);
146		SAFE_FREE(p);
147	}
148}
149
150
151/****************************************************************************
152 Fetch and clean the pid_t record list for all pids interested in notify
153 messages. data needs freeing on exit.
154****************************************************************************/
155
156TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, BOOL cleanlist)
157{
158	TDB_DATA data;
159	size_t i;
160
161	ZERO_STRUCT(data);
162
163	data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
164
165	if (!data.dptr) {
166		ZERO_STRUCT(data);
167		return data;
168	}
169
170	if (data.dsize % 8) {
171		DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
172		tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
173		SAFE_FREE(data.dptr);
174		ZERO_STRUCT(data);
175		return data;
176	}
177
178	if (!cleanlist)
179		return data;
180
181	/*
182	 * Weed out all dead entries.
183	 */
184
185	for( i = 0; i < data.dsize; i += 8) {
186		pid_t pid = (pid_t)IVAL(data.dptr, i);
187
188		if (pid == sys_getpid())
189			continue;
190
191		/* Entry is dead if process doesn't exist or refcount is zero. */
192
193		while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
194
195			/* Refcount == zero is a logic error and should never happen. */
196			if (IVAL(data.dptr, i + 4) == 0) {
197				DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
198							(unsigned int)pid, printer_name ));
199			}
200
201			if (data.dsize - i > 8)
202				memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
203			data.dsize -= 8;
204		}
205	}
206
207	return data;
208}
209
210
211