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                 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
 125 void 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
 135 void 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
 156 TDB_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