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 3 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, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "system/filesys.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         char *printdb_path = NULL;
  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         if (asprintf(&printdb_path, "%s%s.tdb",
  95                                 cache_path("printing/"),
  96                                 printername) < 0) {
  97                 DLIST_REMOVE(print_db_head, p);
  98                 SAFE_FREE(p);
  99                 return NULL;
 100         }
 101
 102         if (geteuid() != sec_initial_uid()) {
 103                 become_root();
 104                 done_become_root = True;
 105         }
 106
 107         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
 108                 0600);
 109
 110         if (done_become_root)
 111                 unbecome_root();
 112
 113         if (!p->tdb) {
 114                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 115                                         printdb_path ));
 116                 DLIST_REMOVE(print_db_head, p);
 117                 SAFE_FREE(printdb_path);
 118                 SAFE_FREE(p);
 119                 return NULL;
 120         }
 121         SAFE_FREE(printdb_path);
 122         fstrcpy(p->printer_name, printername);
 123         p->ref_count++;
 124         return p;
 125 }
 126
 127 /***************************************************************************
 128  Remove a reference count.
 129 ****************************************************************************/
 130
 131 void release_print_db( struct tdb_print_db *pdb)
 132 {
 133         pdb->ref_count--;
 134         SMB_ASSERT(pdb->ref_count >= 0);
 135 }
 136
 137 /***************************************************************************
 138  Close all open print db entries.
 139 ****************************************************************************/
 140
 141 void close_all_print_db(void)
 142 {
 143         struct tdb_print_db *p = NULL, *next_p = NULL;
 144
 145         for (p = print_db_head; p; p = next_p) {
 146                 next_p = p->next;
 147
 148                 if (p->tdb)
 149                         tdb_close(p->tdb);
 150                 DLIST_REMOVE(print_db_head, p);
 151                 ZERO_STRUCTP(p);
 152                 SAFE_FREE(p);
 153         }
 154 }
 155
 156
 157 /****************************************************************************
 158  Fetch and clean the pid_t record list for all pids interested in notify
 159  messages. data needs freeing on exit.
 160 ****************************************************************************/
 161
 162 TDB_DATA get_printer_notify_pid_list(TDB_CONTEXT *tdb, const char *printer_name, bool cleanlist)
 163 {
 164         TDB_DATA data;
 165         size_t i;
 166
 167         ZERO_STRUCT(data);
 168
 169         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 170
 171         if (!data.dptr) {
 172                 ZERO_STRUCT(data);
 173                 return data;
 174         }
 175
 176         if (data.dsize % 8) {
 177                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 178                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 179                 SAFE_FREE(data.dptr);
 180                 ZERO_STRUCT(data);
 181                 return data;
 182         }
 183
 184         if (!cleanlist)
 185                 return data;
 186
 187         /*
 188          * Weed out all dead entries.
 189          */
 190
 191         for( i = 0; i < data.dsize; i += 8) {
 192                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 193
 194                 if (pid == sys_getpid())
 195                         continue;
 196
 197                 /* Entry is dead if process doesn't exist or refcount is zero. */
 198
 199                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
 200
 201                         /* Refcount == zero is a logic error and should never happen. */
 202                         if (IVAL(data.dptr, i + 4) == 0) {
 203                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 204                                                         (unsigned int)pid, printer_name ));
 205                         }
 206
 207                         if (data.dsize - i > 8)
 208                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 209                         data.dsize -= 8;
 210                 }
 211         }
 212
 213         return data;
 214 }
 215
 216