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/passwd.h" /* uid_wrapper */
  24 #include "system/filesys.h"
  25 #include "printing.h"
  26 #include "util_tdb.h"
  27
  28 static struct tdb_print_db *print_db_head;
  29
  30 /****************************************************************************
  31   Function to find or create the printer specific job tdb given a printername.
  32   Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
  33 ****************************************************************************/
  34
  35 struct tdb_print_db *get_print_db_byname(const char *printername)
  36 {
  37         struct tdb_print_db *p = NULL, *last_entry = NULL;
  38         int num_open = 0;
  39         char *printdb_path = NULL;
  40         bool done_become_root = False;
  41         char *print_cache_path;
  42         int ret;
  43
  44         SMB_ASSERT(printername != NULL);
  45
  46         for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
  47                 /* Ensure the list terminates... JRA. */
  48                 SMB_ASSERT(p->next != print_db_head);
  49
  50                 if (p->tdb && strequal(p->printer_name, printername)) {
  51                         DLIST_PROMOTE(print_db_head, p);
  52                         p->ref_count++;
  53                         return p;
  54                 }
  55                 num_open++;
  56                 last_entry = p;
  57         }
  58
  59         /* Not found. */
  60         if (num_open >= MAX_PRINT_DBS_OPEN) {
  61                 /* Try and recycle the last entry. */
  62                 if (print_db_head && last_entry) {
  63                         DLIST_PROMOTE(print_db_head, last_entry);
  64                 }
  65
  66                 for (p = print_db_head; p; p = p->next) {
  67                         if (p->ref_count)
  68                                 continue;
  69                         if (p->tdb) {
  70                                 if (tdb_close(p->tdb)) {
  71                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  72                                                                 p->printer_name ));
  73                                         return NULL;
  74                                 }
  75                         }
  76                         p->tdb = NULL;
  77                         p->ref_count = 0;
  78                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  79                         break;
  80                 }
  81                 if (p && print_db_head) {
  82                         DLIST_PROMOTE(print_db_head, p);
  83                         p = print_db_head;
  84                 }
  85         }
  86
  87         if (!p) {
  88                 /* Create one. */
  89                 p = SMB_MALLOC_P(struct tdb_print_db);
  90                 if (!p) {
  91                         DEBUG(0,("get_print_db: malloc fail !\n"));
  92                         return NULL;
  93                 }
  94                 ZERO_STRUCTP(p);
  95                 DLIST_ADD(print_db_head, p);
  96         }
  97
  98         print_cache_path = cache_path("printing/");
  99         if (print_cache_path == NULL) {
 100                 DLIST_REMOVE(print_db_head, p);
 101                 SAFE_FREE(p);
 102                 return NULL;
 103         }
 104         ret = asprintf(&printdb_path, "%s%s.tdb",
 105                        print_cache_path, printername);
 106         TALLOC_FREE(print_cache_path);
 107         if (ret < 0) {
 108                 DLIST_REMOVE(print_db_head, p);
 109                 SAFE_FREE(p);
 110                 return NULL;
 111         }
 112
 113         if (geteuid() != sec_initial_uid()) {
 114                 become_root();
 115                 done_become_root = True;
 116         }
 117
 118         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
 119                 0600);
 120
 121         if (done_become_root)
 122                 unbecome_root();
 123
 124         if (!p->tdb) {
 125                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 126                                         printdb_path ));
 127                 DLIST_REMOVE(print_db_head, p);
 128                 SAFE_FREE(printdb_path);
 129                 SAFE_FREE(p);
 130                 return NULL;
 131         }
 132         SAFE_FREE(printdb_path);
 133         fstrcpy(p->printer_name, printername);
 134         p->ref_count++;
 135         return p;
 136 }
 137
 138 /***************************************************************************
 139  Remove a reference count.
 140 ****************************************************************************/
 141
 142 void release_print_db( struct tdb_print_db *pdb)
 143 {
 144         pdb->ref_count--;
 145         SMB_ASSERT(pdb->ref_count >= 0);
 146 }
 147
 148 /***************************************************************************
 149  Close all open print db entries.
 150 ****************************************************************************/
 151
 152 void close_all_print_db(void)
 153 {
 154         struct tdb_print_db *p = NULL, *next_p = NULL;
 155
 156         for (p = print_db_head; p; p = next_p) {
 157                 next_p = p->next;
 158
 159                 if (p->tdb)
 160                         tdb_close(p->tdb);
 161                 DLIST_REMOVE(print_db_head, p);
 162                 ZERO_STRUCTP(p);
 163                 SAFE_FREE(p);
 164         }
 165 }
 166
 167
 168 /****************************************************************************
 169  Fetch and clean the pid_t record list for all pids interested in notify
 170  messages. data needs freeing on exit.
 171 ****************************************************************************/
 172
 173 TDB_DATA get_printer_notify_pid_list(struct tdb_context *tdb, const char *printer_name, bool cleanlist)
 174 {
 175         TDB_DATA data;
 176         size_t i;
 177
 178         ZERO_STRUCT(data);
 179
 180         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 181
 182         if (!data.dptr) {
 183                 ZERO_STRUCT(data);
 184                 return data;
 185         }
 186
 187         if (data.dsize % 8) {
 188                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 189                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 190                 SAFE_FREE(data.dptr);
 191                 ZERO_STRUCT(data);
 192                 return data;
 193         }
 194
 195         if (!cleanlist)
 196                 return data;
 197
 198         /*
 199          * Weed out all dead entries.
 200          */
 201
 202         for( i = 0; i < data.dsize; i += 8) {
 203                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 204
 205                 if (pid == getpid())
 206                         continue;
 207
 208                 /* Entry is dead if process doesn't exist or refcount is zero. */
 209
 210                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
 211
 212                         /* Refcount == zero is a logic error and should never happen. */
 213                         if (IVAL(data.dptr, i + 4) == 0) {
 214                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 215                                                         (unsigned int)pid, printer_name ));
 216                         }
 217
 218                         if (data.dsize - i > 8)
 219                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 220                         data.dsize -= 8;
 221                 }
 222         }
 223
 224         return data;
 225 }
 226
 227