summaryrefslogtreecommitdiffstats
path: root/source3/printing/printing_db.c
blob: 94319f96d0bd1b4e51af37c0bfd778d8b601e76c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/* 
   Unix SMB/Netbios implementation.
   Version 3.0
   printing backend routines
   Copyright (C) Andrew Tridgell 1992-2000
   Copyright (C) Jeremy Allison 2002
   
   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/>.
*/

#include "includes.h"
#include "printing.h"

static struct tdb_print_db *print_db_head;

/****************************************************************************
  Function to find or create the printer specific job tdb given a printername.
  Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
****************************************************************************/

struct tdb_print_db *get_print_db_byname(const char *printername)
{
	struct tdb_print_db *p = NULL, *last_entry = NULL;
	int num_open = 0;
	char *printdb_path = NULL;
	bool done_become_root = False;

	SMB_ASSERT(printername != NULL);

	for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
		/* Ensure the list terminates... JRA. */
		SMB_ASSERT(p->next != print_db_head);

		if (p->tdb && strequal(p->printer_name, printername)) {
			DLIST_PROMOTE(print_db_head, p);
			p->ref_count++;
			return p;
		}
		num_open++;
		last_entry = p;
	}

	/* Not found. */
	if (num_open >= MAX_PRINT_DBS_OPEN) {
		/* Try and recycle the last entry. */
		if (print_db_head && last_entry) {
			DLIST_PROMOTE(print_db_head, last_entry);
		}

		for (p = print_db_head; p; p = p->next) {
			if (p->ref_count)
				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;
				}
			}
			p->tdb = NULL;
			p->ref_count = 0;
			memset(p->printer_name, '\0', sizeof(p->printer_name));
			break;
		}
		if (p && print_db_head) {
			DLIST_PROMOTE(print_db_head, p);
			p = print_db_head;
		}
	}

	if (!p)	{
		/* Create one. */
		p = SMB_MALLOC_P(struct tdb_print_db);
		if (!p) {
			DEBUG(0,("get_print_db: malloc fail !\n"));
			return NULL;
		}
		ZERO_STRUCTP(p);
		DLIST_ADD(print_db_head, p);
	}

	if (asprintf(&printdb_path, "%s%s.tdb",
				lock_path("printing/"),
				printername) < 0) {
		DLIST_REMOVE(print_db_head, p);
		SAFE_FREE(p);
		return NULL;
	}

	if (geteuid() != 0) {
		become_root();
		done_become_root = True;
	}

	p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT, 
		0600);

	if (done_become_root)
		unbecome_root();

	if (!p->tdb) {
		DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
					printdb_path ));
		DLIST_REMOVE(print_db_head, p);
		SAFE_FREE(printdb_path);
		SAFE_FREE(p);
		return NULL;
	}
	SAFE_FREE(printdb_path);
	fstrcpy(p->printer_name, printername);
	p->ref_count++;
	return p;
}

/***************************************************************************
 Remove a reference count.
****************************************************************************/

void release_print_db( struct tdb_print_db *pdb)
{
	pdb->ref_count--;
	SMB_ASSERT(pdb->ref_count >= 0);
}

/***************************************************************************
 Close all open print db entries.
****************************************************************************/

void close_all_print_db(void)
{
	struct tdb_print_db *p = NULL, *next_p = NULL;

	for (p = print_db_head; p; p = next_p) {
		next_p = p->next;

		if (p->tdb)
			tdb_close(p->tdb);
		DLIST_REMOVE(print_db_head, p);
		ZERO_STRUCTP(p);
		SAFE_FREE(p);
	}
}


/****************************************************************************
 Fetch and clean the pid_t record list for all pids interested in notify
 messages. data needs freeing on exit.
****************************************************************************/

TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, bool cleanlist)
{
	TDB_DATA data;
	size_t i;

	ZERO_STRUCT(data);

	data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );

	if (!data.dptr) {
		ZERO_STRUCT(data);
		return data;
	}

	if (data.dsize % 8) {
		DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
		tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
		SAFE_FREE(data.dptr);
		ZERO_STRUCT(data);
		return data;
	}

	if (!cleanlist)
		return data;

	/*
	 * Weed out all dead entries.
	 */

	for( i = 0; i < data.dsize; i += 8) {
		pid_t pid = (pid_t)IVAL(data.dptr, i);

		if (pid == sys_getpid())
			continue;

		/* Entry is dead if process doesn't exist or refcount is zero. */

		while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {

			/* Refcount == zero is a logic error and should never happen. */
			if (IVAL(data.dptr, i + 4) == 0) {
				DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
							(unsigned int)pid, printer_name ));
			}

			if (data.dsize - i > 8)
				memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
			data.dsize -= 8;
		}
	}

	return data;
}