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 #include "util_tdb.h"
  26
  27 static struct tdb_print_db *print_db_head;
  28
  29 /****************************************************************************
  30   Function to find or create the printer specific job tdb given a printername.
  31   Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
  32 ****************************************************************************/
  33
  34 struct tdb_print_db *get_print_db_byname(const char *printername)
  35 {
  36         struct tdb_print_db *p = NULL, *last_entry = NULL;
  37         int num_open = 0;
  38         char *printdb_path = NULL;
  39         bool done_become_root = False;
  40
  41         SMB_ASSERT(printername != NULL);
  42
  43         for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
  44                 /* Ensure the list terminates... JRA. */
  45                 SMB_ASSERT(p->next != print_db_head);
  46
  47                 if (p->tdb && strequal(p->printer_name, printername)) {
  48                         DLIST_PROMOTE(print_db_head, p);
  49                         p->ref_count++;
  50                         return p;
  51                 }
  52                 num_open++;
  53                 last_entry = p;
  54         }
  55
  56         /* Not found. */
  57         if (num_open >= MAX_PRINT_DBS_OPEN) {
  58                 /* Try and recycle the last entry. */
  59                 if (print_db_head && last_entry) {
  60                         DLIST_PROMOTE(print_db_head, last_entry);
  61                 }
  62
  63                 for (p = print_db_head; p; p = p->next) {
  64                         if (p->ref_count)
  65                                 continue;
  66                         if (p->tdb) {
  67                                 if (tdb_close(print_db_head->tdb)) {
  68                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  69                                                                 print_db_head->printer_name ));
  70                                         return NULL;
  71                                 }
  72                         }
  73                         p->tdb = NULL;
  74                         p->ref_count = 0;
  75                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  76                         break;
  77                 }
  78                 if (p && print_db_head) {
  79                         DLIST_PROMOTE(print_db_head, p);
  80                         p = print_db_head;
  81                 }
  82         }
  83
  84         if (!p) {
  85                 /* Create one. */
  86                 p = SMB_MALLOC_P(struct tdb_print_db);
  87                 if (!p) {
  88                         DEBUG(0,("get_print_db: malloc fail !\n"));
  89                         return NULL;
  90                 }
  91                 ZERO_STRUCTP(p);
  92                 DLIST_ADD(print_db_head, p);
  93         }
  94
  95         if (asprintf(&printdb_path, "%s%s.tdb",
  96                                 cache_path("printing/"),
  97                                 printername) < 0) {
  98                 DLIST_REMOVE(print_db_head, p);
  99                 SAFE_FREE(p);
 100                 return NULL;
 101         }
 102
 103         if (geteuid() != sec_initial_uid()) {
 104                 become_root();
 105                 done_become_root = True;
 106         }
 107
 108         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
 109                 0600);
 110
 111         if (done_become_root)
 112                 unbecome_root();
 113
 114         if (!p->tdb) {
 115                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 116                                         printdb_path ));
 117                 DLIST_REMOVE(print_db_head, p);
 118                 SAFE_FREE(printdb_path);
 119                 SAFE_FREE(p);
 120                 return NULL;
 121         }
 122         SAFE_FREE(printdb_path);
 123         fstrcpy(p->printer_name, printername);
 124         p->ref_count++;
 125         return p;
 126 }
 127
 128 /***************************************************************************
 129  Remove a reference count.
 130 ****************************************************************************/
 131
 132 void release_print_db( struct tdb_print_db *pdb)
 133 {
 134         pdb->ref_count--;
 135         SMB_ASSERT(pdb->ref_count >= 0);
 136 }
 137
 138 /***************************************************************************
 139  Close all open print db entries.
 140 ****************************************************************************/
 141
 142 void close_all_print_db(void)
 143 {
 144         struct tdb_print_db *p = NULL, *next_p = NULL;
 145
 146         for (p = print_db_head; p; p = next_p) {
 147                 next_p = p->next;
 148
 149                 if (p->tdb)
 150                         tdb_close(p->tdb);
 151                 DLIST_REMOVE(print_db_head, p);
 152                 ZERO_STRUCTP(p);
 153                 SAFE_FREE(p);
 154         }
 155 }
 156
 157
 158 /****************************************************************************
 159  Fetch and clean the pid_t record list for all pids interested in notify
 160  messages. data needs freeing on exit.
 161 ****************************************************************************/
 162
 163 TDB_DATA get_printer_notify_pid_list(struct tdb_context *tdb, const char *printer_name, bool cleanlist)
 164 {
 165         TDB_DATA data;
 166         size_t i;
 167
 168         ZERO_STRUCT(data);
 169
 170         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 171
 172         if (!data.dptr) {
 173                 ZERO_STRUCT(data);
 174                 return data;
 175         }
 176
 177         if (data.dsize % 8) {
 178                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 179                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 180                 SAFE_FREE(data.dptr);
 181                 ZERO_STRUCT(data);
 182                 return data;
 183         }
 184
 185         if (!cleanlist)
 186                 return data;
 187
 188         /*
 189          * Weed out all dead entries.
 190          */
 191
 192         for( i = 0; i < data.dsize; i += 8) {
 193                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 194
 195                 if (pid == sys_getpid())
 196                         continue;
 197
 198                 /* Entry is dead if process doesn't exist or refcount is zero. */
 199
 200                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
 201
 202                         /* Refcount == zero is a logic error and should never happen. */
 203                         if (IVAL(data.dptr, i + 4) == 0) {
 204                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 205                                                         (unsigned int)pid, printer_name ));
 206                         }
 207
 208                         if (data.dsize - i > 8)
 209                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 210                         data.dsize -= 8;
 211                 }
 212         }
 213
 214         return data;
 215 }
 216
 217