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