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 "printing.h"
  24
  25 static struct tdb_print_db *print_db_head;
  26
  27 /****************************************************************************
  28   Function to find or create the printer specific job tdb given a printername.
  29   Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
  30 ****************************************************************************/
  31
  32 struct tdb_print_db *get_print_db_byname(const char *printername)
  33 {
  34         struct tdb_print_db *p = NULL, *last_entry = NULL;
  35         int num_open = 0;
  36         pstring printdb_path;
  37         BOOL done_become_root = False;
  38
  39         for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
  40                 /* Ensure the list terminates... JRA. */
  41                 SMB_ASSERT(p->next != print_db_head);
  42
  43                 if (p->tdb && strequal(p->printer_name, printername)) {
  44                         DLIST_PROMOTE(print_db_head, p);
  45                         p->ref_count++;
  46                         return p;
  47                 }
  48                 num_open++;
  49                 last_entry = p;
  50         }
  51
  52         /* Not found. */
  53         if (num_open >= MAX_PRINT_DBS_OPEN) {
  54                 /* Try and recycle the last entry. */
  55                 DLIST_PROMOTE(print_db_head, last_entry);
  56
  57                 for (p = print_db_head; p; p = p->next) {
  58                         if (p->ref_count)
  59                                 continue;
  60                         if (p->tdb) {
  61                                 if (tdb_close(print_db_head->tdb)) {
  62                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  63                                                                 print_db_head->printer_name ));
  64                                         return NULL;
  65                                 }
  66                         }
  67                         p->tdb = NULL;
  68                         p->ref_count = 0;
  69                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  70                         break;
  71                 }
  72                 if (p) {
  73                         DLIST_PROMOTE(print_db_head, p);
  74                         p = print_db_head;
  75                 }
  76         }
  77
  78         if (!p) {
  79                 /* Create one. */
  80                 p = (struct tdb_print_db *)malloc(sizeof(struct tdb_print_db));
  81                 if (!p) {
  82                         DEBUG(0,("get_print_db: malloc fail !\n"));
  83                         return NULL;
  84                 }
  85                 ZERO_STRUCTP(p);
  86                 DLIST_ADD(print_db_head, p);
  87         }
  88
  89         pstrcpy(printdb_path, lock_path("printing/"));
  90         pstrcat(printdb_path, printername);
  91         pstrcat(printdb_path, ".tdb");
  92
  93         if (geteuid() != 0) {
  94                 become_root();
  95                 done_become_root = True;
  96         }
  97
  98         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
  99
 100         if (done_become_root)
 101                 unbecome_root();
 102
 103         if (!p->tdb) {
 104                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 105                                         printdb_path ));
 106                 DLIST_REMOVE(print_db_head, p);
 107                 SAFE_FREE(p);
 108                 return NULL;
 109         }
 110         fstrcpy(p->printer_name, printername);
 111         p->ref_count++;
 112         return p;
 113 }
 114
 115 /***************************************************************************
 116  Remove a reference count.
 117 ****************************************************************************/
 118
 119 void release_print_db( struct tdb_print_db *pdb)
 120 {
 121         pdb->ref_count--;
 122         SMB_ASSERT(pdb->ref_count >= 0);
 123 }
 124
 125 /***************************************************************************
 126  Close all open print db entries.
 127 ****************************************************************************/
 128
 129 void close_all_print_db(void)
 130 {
 131         struct tdb_print_db *p = NULL, *next_p = NULL;
 132
 133         for (p = print_db_head; p; p = next_p) {
 134                 next_p = p->next;
 135
 136                 if (p->tdb)
 137                         tdb_close(p->tdb);
 138                 DLIST_REMOVE(print_db_head, p);
 139                 ZERO_STRUCTP(p);
 140                 SAFE_FREE(p);
 141         }
 142 }
 143
 144
 145 /****************************************************************************
 146  Fetch and clean the pid_t record list for all pids interested in notify
 147  messages. data needs freeing on exit.
 148 ****************************************************************************/
 149
 150 TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, BOOL cleanlist)
 151 {
 152         TDB_DATA data;
 153         size_t i;
 154
 155         ZERO_STRUCT(data);
 156
 157         data = tdb_fetch_by_string( tdb, NOTIFY_PID_LIST_KEY );
 158
 159         if (!data.dptr) {
 160                 ZERO_STRUCT(data);
 161                 return data;
 162         }
 163
 164         if (data.dsize % 8) {
 165                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 166                 tdb_delete_by_string(tdb, NOTIFY_PID_LIST_KEY );
 167                 SAFE_FREE(data.dptr);
 168                 ZERO_STRUCT(data);
 169                 return data;
 170         }
 171
 172         if (!cleanlist)
 173                 return data;
 174
 175         /*
 176          * Weed out all dead entries.
 177          */
 178
 179         for( i = 0; i < data.dsize; i += 8) {
 180                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 181
 182                 if (pid == sys_getpid())
 183                         continue;
 184
 185                 /* Entry is dead if process doesn't exist or refcount is zero. */
 186
 187                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists(pid))) {
 188
 189                         /* Refcount == zero is a logic error and should never happen. */
 190                         if (IVAL(data.dptr, i + 4) == 0) {
 191                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 192                                                         (unsigned int)pid, printer_name ));
 193                         }
 194
 195                         if (data.dsize - i > 8)
 196                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 197                         data.dsize -= 8;
 198                 }
 199         }
 200
 201         return data;
 202 }
 203
 204