source3/printing/printing_db.c

   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
  26 static 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
  33 struct 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                 DLIST_PROMOTE(print_db_head, last_entry);
  59
  60                 for (p = print_db_head; p; p = p->next) {
  61                         if (p->ref_count)
  62                                 continue;
  63                         if (p->tdb) {
  64                                 if (tdb_close(print_db_head->tdb)) {
  65                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  66                                                                 print_db_head->printer_name ));
  67                                         return NULL;
  68                                 }
  69                         }
  70                         p->tdb = NULL;
  71                         p->ref_count = 0;
  72                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  73                         break;
  74                 }
  75                 if (p) {
  76                         DLIST_PROMOTE(print_db_head, p);
  77                         p = print_db_head;
  78                 }
  79         }
  80
  81         if (!p) {
  82                 /* Create one. */
  83                 p = SMB_MALLOC_P(struct tdb_print_db);
  84                 if (!p) {
  85                         DEBUG(0,("get_print_db: malloc fail !\n"));
  86                         return NULL;
  87                 }
  88                 ZERO_STRUCTP(p);
  89                 DLIST_ADD(print_db_head, p);
  90         }
  91
  92         pstrcpy(printdb_path, lock_path("printing/"));
  93         pstrcat(printdb_path, printername);
  94         pstrcat(printdb_path, ".tdb");
  95
  96         if (geteuid() != 0) {
  97                 become_root();
  98                 done_become_root = True;
  99         }
 100
 101         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
 102                 0600);
 103
 104         if (done_become_root)
 105                 unbecome_root();
 106
 107         if (!p->tdb) {
 108                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 109                                         printdb_path ));
 110                 DLIST_REMOVE(print_db_head, p);
 111                 SAFE_FREE(p);
 112                 return NULL;
 113         }
 114         fstrcpy(p->printer_name, printername);
 115         p->ref_count++;
 116         return p;
 117 }
 118
 119 /***************************************************************************
 120  Remove a reference count.
 121 ****************************************************************************/
 122
 123 void release_print_db( struct tdb_print_db *pdb)
 124 {
 125         pdb->ref_count--;
 126         SMB_ASSERT(pdb->ref_count >= 0);
 127 }
 128
 129 /***************************************************************************
 130  Close all open print db entries.
 131 ****************************************************************************/
 132
 133 void close_all_print_db(void)
 134 {
 135         struct tdb_print_db *p = NULL, *next_p = NULL;
 136
 137         for (p = print_db_head; p; p = next_p) {
 138                 next_p = p->next;
 139
 140                 if (p->tdb)
 141                         tdb_close(p->tdb);
 142                 DLIST_REMOVE(print_db_head, p);
 143                 ZERO_STRUCTP(p);
 144                 SAFE_FREE(p);
 145         }
 146 }
 147
 148
 149 /****************************************************************************
 150  Fetch and clean the pid_t record list for all pids interested in notify
 151  messages. data needs freeing on exit.
 152 ****************************************************************************/
 153
 154 TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, BOOL cleanlist)
 155 {
 156         TDB_DATA data;
 157         size_t i;
 158
 159         ZERO_STRUCT(data);
 160
 161         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 162
 163         if (!data.dptr) {
 164                 ZERO_STRUCT(data);
 165                 return data;
 166         }
 167
 168         if (data.dsize % 8) {
 169                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 170                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 171                 SAFE_FREE(data.dptr);
 172                 ZERO_STRUCT(data);
 173                 return data;
 174         }
 175
 176         if (!cleanlist)
 177                 return data;
 178
 179         /*
 180          * Weed out all dead entries.
 181          */
 182
 183         for( i = 0; i < data.dsize; i += 8) {
 184                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 185
 186                 if (pid == sys_getpid())
 187                         continue;
 188
 189                 /* Entry is dead if process doesn't exist or refcount is zero. */
 190
 191                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
 192
 193                         /* Refcount == zero is a logic error and should never happen. */
 194                         if (IVAL(data.dptr, i + 4) == 0) {
 195                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 196                                                         (unsigned int)pid, printer_name ));
 197                         }
 198
 199                         if (data.dsize - i > 8)
 200                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 201                         data.dsize -= 8;
 202                 }
 203         }
 204
 205         return data;
 206 }
 207
 208