source/ntvfs/ntvfs_base.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    NTVFS base code
   4
   5    Copyright (C) Andrew Tridgell 2003
   6    Copyright (C) Stefan (metze) Metzmacher 2004
   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 2 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, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22 /*
  23   this implements the core code for all NTVFS modules. Backends register themselves here.
  24 */
  25
  26 #include "includes.h"
  27 #include "dlinklist.h"
  28 #include "smb_server/smb_server.h"
  29
  30
  31
  32 /* the list of currently registered NTVFS backends, note that there
  33  * can be more than one backend with the same name, as long as they
  34  * have different typesx */
  35 static struct {
  36         const struct ntvfs_ops *ops;
  37 } *backends = NULL;
  38 static int num_backends;
  39
  40 /*
  41   register a NTVFS backend.
  42
  43   The 'name' can be later used by other backends to find the operations
  44   structure for this backend.
  45
  46   The 'type' is used to specify whether this is for a disk, printer or IPC$ share
  47 */
  48 NTSTATUS ntvfs_register(const void *_ops)
  49 {
  50         const struct ntvfs_ops *ops = _ops;
  51         struct ntvfs_ops *new_ops;
  52
  53         if (ntvfs_backend_byname(ops->name, ops->type) != NULL) {
  54                 /* its already registered! */
  55                 DEBUG(0,("NTVFS backend '%s' for type %d already registered\n",
  56                          ops->name, (int)ops->type));
  57                 return NT_STATUS_OBJECT_NAME_COLLISION;
  58         }
  59
  60         backends = Realloc(backends, sizeof(backends[0]) * (num_backends+1));
  61         if (!backends) {
  62                 smb_panic("out of memory in ntvfs_register");
  63         }
  64
  65         new_ops = smb_xmemdup(ops, sizeof(*ops));
  66         new_ops->name = smb_xstrdup(ops->name);
  67
  68         backends[num_backends].ops = new_ops;
  69
  70         num_backends++;
  71
  72         DEBUG(3,("NTVFS backend '%s' for type %d registered\n",
  73                  ops->name,ops->type));
  74
  75         return NT_STATUS_OK;
  76 }
  77
  78
  79 /*
  80   return the operations structure for a named backend of the specified type
  81 */
  82 const struct ntvfs_ops *ntvfs_backend_byname(const char *name, enum ntvfs_type type)
  83 {
  84         int i;
  85
  86         for (i=0;i<num_backends;i++) {
  87                 if (backends[i].ops->type == type &&
  88                     strcmp(backends[i].ops->name, name) == 0) {
  89                         return backends[i].ops;
  90                 }
  91         }
  92
  93         return NULL;
  94 }
  95
  96
  97 /*
  98   return the NTVFS interface version, and the size of some critical types
  99   This can be used by backends to either detect compilation errors, or provide
 100   multiple implementations for different smbd compilation options in one module
 101 */
 102 const struct ntvfs_critical_sizes *ntvfs_interface_version(void)
 103 {
 104         static const struct ntvfs_critical_sizes critical_sizes = {
 105                 NTVFS_INTERFACE_VERSION,
 106                 sizeof(struct ntvfs_critical_sizes),
 107                 sizeof(struct ntvfs_context),
 108                 sizeof(struct ntvfs_module_context),
 109                 sizeof(struct ntvfs_ops),
 110                 sizeof(struct ntvfs_async_state),
 111                 sizeof(struct smbsrv_tcon),
 112                 sizeof(struct smbsrv_request),
 113         };
 114
 115         return &critical_sizes;
 116 }
 117
 118
 119 /*
 120   initialise a connection structure to point at a NTVFS backend
 121 */
 122 NTSTATUS ntvfs_init_connection(struct smbsrv_request *req, enum ntvfs_type type)
 123 {
 124         const char **handlers = lp_ntvfs_handler(req->tcon->service);
 125         int i;
 126         struct ntvfs_context *ctx;
 127
 128         if (!handlers) {
 129                 return NT_STATUS_FOOBAR;
 130         }
 131
 132         ctx = talloc_p(req->tcon, struct ntvfs_context);
 133         if (!ctx) {
 134                 return NT_STATUS_NO_MEMORY;
 135         }
 136         ctx->type = type;
 137         ctx->modules = NULL;
 138
 139         for (i=0; handlers[i]; i++) {
 140                 struct ntvfs_module_context *ntvfs;
 141
 142                 ntvfs = talloc_p(ctx, struct ntvfs_module_context);
 143                 if (!ntvfs) {
 144                         return NT_STATUS_NO_MEMORY;
 145                 }
 146
 147                 ntvfs->ops = ntvfs_backend_byname(handlers[i], ctx->type);
 148                 if (!ntvfs->ops) {
 149                         DEBUG(1,("ntvfs_init_connection: failed to find backend=%s, type=%d\n",
 150                                 handlers[i], ctx->type));
 151                         return NT_STATUS_UNSUCCESSFUL;
 152                 }
 153                 ntvfs->depth = i;
 154                 DLIST_ADD_END(ctx->modules, ntvfs, struct ntvfs_module_context *);
 155         }
 156
 157         if (!ctx->modules) {
 158                 talloc_free(ctx);
 159                 return NT_STATUS_FOOBAR;
 160         }
 161
 162         req->tcon->ntvfs_ctx = ctx;
 163
 164         return NT_STATUS_OK;
 165 }