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 #include "lib/util/string_wrappers.h"
  28
  29 static struct tdb_print_db *print_db_head;
  30
  31 /****************************************************************************
  32   Function to find or create the printer specific job tdb given a printername.
  33   Limits the number of tdb's open to MAX_PRINT_DBS_OPEN.
  34 ****************************************************************************/
  35
  36 struct tdb_print_db *get_print_db_byname(const char *printername)
  37 {
  38         struct tdb_print_db *p = NULL, *last_entry = NULL;
  39         size_t num_open = 0;
  40         char *printdb_path = NULL;
  41         bool done_become_root = False;
  42         char *print_cache_path;
  43         int ret;
  44
  45         SMB_ASSERT(printername != NULL);
  46
  47         for (p = print_db_head, last_entry = print_db_head; p; p = p->next) {
  48                 /* Ensure the list terminates... JRA. */
  49                 SMB_ASSERT(p->next != print_db_head);
  50
  51                 if (p->tdb && strequal(p->printer_name, printername)) {
  52                         DLIST_PROMOTE(print_db_head, p);
  53                         p->ref_count++;
  54                         return p;
  55                 }
  56                 num_open++;
  57                 last_entry = p;
  58         }
  59
  60         /* Not found. */
  61         if (num_open >= MAX_PRINT_DBS_OPEN) {
  62                 /* Try and recycle the last entry. */
  63                 if (print_db_head && last_entry) {
  64                         DLIST_PROMOTE(print_db_head, last_entry);
  65                 }
  66
  67                 for (p = print_db_head; p; p = p->next) {
  68                         if (p->ref_count)
  69                                 continue;
  70                         if (p->tdb) {
  71                                 if (tdb_close(p->tdb)) {
  72                                         DEBUG(0,("get_print_db: Failed to close tdb for printer %s\n",
  73                                                                 p->printer_name ));
  74                                         return NULL;
  75                                 }
  76                         }
  77                         p->tdb = NULL;
  78                         p->ref_count = 0;
  79                         memset(p->printer_name, '\0', sizeof(p->printer_name));
  80                         break;
  81                 }
  82                 if (p && print_db_head) {
  83                         DLIST_PROMOTE(print_db_head, p);
  84                         p = print_db_head;
  85                 }
  86         }
  87
  88         if (!p) {
  89                 /* Create one. */
  90                 p = SMB_MALLOC_P(struct tdb_print_db);
  91                 if (!p) {
  92                         DEBUG(0,("get_print_db: malloc fail !\n"));
  93                         return NULL;
  94                 }
  95                 ZERO_STRUCTP(p);
  96                 DLIST_ADD(print_db_head, p);
  97         }
  98
  99         print_cache_path = cache_path(talloc_tos(), "printing/");
 100         if (print_cache_path == NULL) {
 101                 DLIST_REMOVE(print_db_head, p);
 102                 SAFE_FREE(p);
 103                 return NULL;
 104         }
 105         ret = asprintf(&printdb_path, "%s%s.tdb",
 106                        print_cache_path, printername);
 107         TALLOC_FREE(print_cache_path);
 108         if (ret < 0) {
 109                 DLIST_REMOVE(print_db_head, p);
 110                 SAFE_FREE(p);
 111                 return NULL;
 112         }
 113
 114         if (geteuid() != sec_initial_uid()) {
 115                 become_root();
 116                 done_become_root = True;
 117         }
 118
 119         p->tdb = tdb_open_log(printdb_path, 5000, TDB_DEFAULT, O_RDWR|O_CREAT,
 120                 0600);
 121
 122         if (done_become_root)
 123                 unbecome_root();
 124
 125         if (!p->tdb) {
 126                 DEBUG(0,("get_print_db: Failed to open printer backend database %s.\n",
 127                                         printdb_path ));
 128                 DLIST_REMOVE(print_db_head, p);
 129                 SAFE_FREE(printdb_path);
 130                 SAFE_FREE(p);
 131                 return NULL;
 132         }
 133         SAFE_FREE(printdb_path);
 134         fstrcpy(p->printer_name, printername);
 135         p->ref_count++;
 136         return p;
 137 }
 138
 139 /***************************************************************************
 140  Remove a reference count.
 141 ****************************************************************************/
 142
 143 void release_print_db( struct tdb_print_db *pdb)
 144 {
 145         pdb->ref_count--;
 146         SMB_ASSERT(pdb->ref_count >= 0);
 147 }
 148
 149 /***************************************************************************
 150  Close all open print db entries.
 151 ****************************************************************************/
 152
 153 void close_all_print_db(void)
 154 {
 155         struct tdb_print_db *p = NULL, *next_p = NULL;
 156
 157         for (p = print_db_head; p; p = next_p) {
 158                 next_p = p->next;
 159
 160                 if (p->tdb)
 161                         tdb_close(p->tdb);
 162                 DLIST_REMOVE(print_db_head, p);
 163                 ZERO_STRUCTP(p);
 164                 SAFE_FREE(p);
 165         }
 166 }
 167
 168
 169 /****************************************************************************
 170  Fetch and clean the pid_t record list for all pids interested in notify
 171  messages. data needs freeing on exit.
 172 ****************************************************************************/
 173
 174 TDB_DATA get_printer_notify_pid_list(struct tdb_context *tdb, const char *printer_name, bool cleanlist)
 175 {
 176         TDB_DATA data;
 177         size_t i;
 178
 179         ZERO_STRUCT(data);
 180
 181         data = tdb_fetch_bystring( tdb, NOTIFY_PID_LIST_KEY );
 182
 183         if (!data.dptr) {
 184                 ZERO_STRUCT(data);
 185                 return data;
 186         }
 187
 188         if (data.dsize % 8) {
 189                 DEBUG(0,("get_printer_notify_pid_list: Size of record for printer %s not a multiple of 8 !\n", printer_name ));
 190                 tdb_delete_bystring(tdb, NOTIFY_PID_LIST_KEY );
 191                 SAFE_FREE(data.dptr);
 192                 ZERO_STRUCT(data);
 193                 return data;
 194         }
 195
 196         if (!cleanlist)
 197                 return data;
 198
 199         /*
 200          * Weed out all dead entries.
 201          */
 202
 203         for( i = 0; i < data.dsize; i += 8) {
 204                 pid_t pid = (pid_t)IVAL(data.dptr, i);
 205
 206                 if (pid == getpid())
 207                         continue;
 208
 209                 /* Entry is dead if process doesn't exist or refcount is zero. */
 210
 211                 while ((i < data.dsize) && ((IVAL(data.dptr, i + 4) == 0) || !process_exists_by_pid(pid))) {
 212
 213                         /* Refcount == zero is a logic error and should never happen. */
 214                         if (IVAL(data.dptr, i + 4) == 0) {
 215                                 DEBUG(0,("get_printer_notify_pid_list: Refcount == 0 for pid = %u printer %s !\n",
 216                                                         (unsigned int)pid, printer_name ));
 217                         }
 218
 219                         if (data.dsize - i > 8)
 220                                 memmove( &data.dptr[i], &data.dptr[i+8], data.dsize - i - 8);
 221                         data.dsize -= 8;
 222                 }
 223         }
 224
 225         return data;
 226 }
 227
 228