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         for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
  41                 /* Ensure the list terminates... JRA. */
  42                 SMB_ASSERT(p->next != print_db_head);
  43
  44                 if (p->tdb && strequal(p->printer_name, printername)) {
  45                         DLIST_PROMOTE(print_db_head, p);
  46                         p->ref_count++;
  47                         return p;
  48                 }
  49                 num_open++;
  50                 last_entry = p;
  51         }
  52
  53         /* Not found. */
  54         if (num_open >= MAX_PRINT_DBS_OPEN) {
  55                 /* Try and recycle the last entry. */
  56                 DLIST_PROMOTE(print_db_head, last_entry);
  57
  58                 for (p = print_db_head; p; p = p->next) {
  59                         if (p->ref_count)
  60                                 continue;
  61                         if (p->tdb) {
  62                                 if (tdb_close(print_db_head->tdb)) {
  63                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  64                                                                 print_db_head->printer_name ));
  65                                         return NULL;
  66                                 }
  67                         }
  68                         p->tdb = NULL;
  69                         p->ref_count = 0;
  70                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  71                         break;
  72                 }
  73                 if (p) {
  74                         DLIST_PROMOTE(print_db_head, p);
  75                         p = print_db_head;
  76                 }
  77         }
  78
  79         if (!p) {
  80                 /* Create one. */
  81                 p = (struct tdb_print_db *)malloc(sizeof(struct tdb_print_db));
  82                 if (!p) {
  83                         DEBUG(0,("get_print_db: malloc fail !\n"));
  84                         return NULL;
  85                 }
  86                 ZERO_STRUCTP(p);
  87                 DLIST_ADD(print_db_head, p);
  88         }
  89
  90         pstrcpy(printdb_path, lock_path("printing/"));
  91         pstrcat(printdb_path, printername);
  92         pstrcat(printdb_path, ".tdb");
  93
  94         if (geteuid() != 0) {
  95                 become_root();
  96                 done_become_root = True;
  97         }
  98
  99         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
 100
 101         if (done_become_root)
 102                 unbecome_root();
 103
 104         if (!p->tdb) {
 105                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 106                                         printdb_path ));
 107                 DLIST_REMOVE(print_db_head, p);
 108                 SAFE_FREE(p);
 109                 return NULL;
 110         }
 111         fstrcpy(p->printer_name, printername);
 112         p->ref_count++;
 113         return p;
 114 }
 115
 116 /***************************************************************************
 117  Remove a reference count.
 118 ****************************************************************************/
 119
 120 void release_print_db( struct tdb_print_db *pdb)
 121 {
 122         pdb->ref_count--;
 123         SMB_ASSERT(pdb->ref_count >= 0);
 124 }
 125
 126 /***************************************************************************
 127  Close all open print db entries.
 128 ****************************************************************************/
 129
 130 void close_all_print_db(void)
 131 {
 132         struct tdb_print_db *p = NULL, *next_p = NULL;
 133
 134         for (p = print_db_head; p; p = next_p) {
 135                 next_p = p->next;
 136
 137                 if (p->tdb)
 138                         tdb_close(p->tdb);
 139                 DLIST_REMOVE(print_db_head, p);
 140                 ZERO_STRUCTP(p);
 141                 SAFE_FREE(p);
 142         }
 143 }
 144
 145
 146 /****************************************************************************
 147  Fetch and clean the pid_t record list for all pids interested in notify
 148  messages. data needs freeing on exit.
 149 ****************************************************************************/
 150
 151 TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, BOOL cleanlist)
 152 {
 153         TDB_DATA data;
 154         size_t i;
 155
 156         ZERO_STRUCT(data);
 157
 158         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 159
 160         if (!data.dptr) {
 161                 ZERO_STRUCT(data);
 162                 return data;
 163         }
 164
 165         if (data.dsize % 8) {
 166                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 167                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 168                 SAFE_FREE(data.dptr);
 169                 ZERO_STRUCT(data);
 170                 return data;
 171         }
 172
 173         if (!cleanlist)
 174                 return data;
 175
 176         /*
 177          * Weed out all dead entries.
 178          */
 179
 180         for( i = 0; i < data.dsize; i += 8) {
 181                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 182
 183                 if (pid == sys_getpid())
 184                         continue;
 185
 186                 /* Entry is dead if process doesn't exist or refcount is zero. */
 187
 188                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists(pid))) {
 189
 190                         /* Refcount == zero is a logic error and should never happen. */
 191                         if (IVAL(data.dptr, i + 4) == 0) {
 192                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 193                                                         (unsigned int)pid, printer_name ));
 194                         }
 195
 196                         if (data.dsize - i > 8)
 197                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 198                         data.dsize -= 8;
 199                 }
 200         }
 201
 202         return data;
 203 }
 204
 205