source4/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 "lib/util/dlinklist.h"
  28 #include "build.h"
  29 #include "ntvfs/ntvfs.h"
  30
  31 /* the list of currently registered NTVFS backends, note that there
  32  * can be more than one backend with the same name, as long as they
  33  * have different typesx */
  34 static struct ntvfs_backend {
  35         const struct ntvfs_ops *ops;
  36 } *backends = NULL;
  37 static int num_backends;
  38
  39 /*
  40   register a NTVFS backend.
  41
  42   The 'name' can be later used by other backends to find the operations
  43   structure for this backend.
  44
  45   The 'type' is used to specify whether this is for a disk, printer or IPC$ share
  46 */
  47 _PUBLIC_ NTSTATUS ntvfs_register(const struct ntvfs_ops *ops,
  48                                  const struct ntvfs_critical_sizes *const sizes)
  49 {
  50         struct ntvfs_ops *new_ops;
  51
  52         if (ntvfs_interface_differs(sizes)) {
  53                 DEBUG(0, ("NTVFS backend '%s' for type %d "
  54                           "failed version check\n",
  55                           ops->name, (int)ops->type));
  56                 return NT_STATUS_BAD_FUNCTION_TABLE;
  57         }
  58
  59         if (ntvfs_backend_byname(ops->name, ops->type) != NULL) {
  60                 /* its already registered! */
  61                 DEBUG(0,("NTVFS backend '%s' for type %d already registered\n",
  62                          ops->name, (int)ops->type));
  63                 return NT_STATUS_OBJECT_NAME_COLLISION;
  64         }
  65
  66         backends = realloc_p(backends, struct ntvfs_backend, num_backends+1);
  67         if (!backends) {
  68                 smb_panic("out of memory in ntvfs_register");
  69         }
  70
  71         new_ops = smb_xmemdup(ops, sizeof(*ops));
  72         new_ops->name = smb_xstrdup(ops->name);
  73
  74         backends[num_backends].ops = new_ops;
  75
  76         num_backends++;
  77
  78         DEBUG(3,("NTVFS backend '%s' for type %d registered\n",
  79                  ops->name,ops->type));
  80
  81         return NT_STATUS_OK;
  82 }
  83
  84
  85 /*
  86   return the operations structure for a named backend of the specified type
  87 */
  88 _PUBLIC_ const struct ntvfs_ops *ntvfs_backend_byname(const char *name, enum ntvfs_type type)
  89 {
  90         int i;
  91
  92         for (i=0;i<num_backends;i++) {
  93                 if (backends[i].ops->type == type &&
  94                     strcmp(backends[i].ops->name, name) == 0) {
  95                         return backends[i].ops;
  96                 }
  97         }
  98
  99         return NULL;
 100 }
 101
 102
 103 /*
 104   return the NTVFS interface version, and the size of some critical types
 105   This can be used by backends to either detect compilation errors, or provide
 106   multiple implementations for different smbd compilation options in one module
 107 */
 108
 109 static const NTVFS_CURRENT_CRITICAL_SIZES(critical_sizes);
 110
 111 _PUBLIC_ const struct ntvfs_critical_sizes *ntvfs_interface_version(void)
 112 {
 113         return &critical_sizes;
 114 }
 115
 116 _PUBLIC_ BOOL ntvfs_interface_differs(const struct ntvfs_critical_sizes *const iface)
 117 {
 118         /* The comparison would be easier with memcmp, but compiler-interset
 119          * alignment padding is not guaranteed to be zeroed.
 120          */
 121
 122 #define FIELD_DIFFERS(field) (iface->field != critical_sizes.field)
 123
 124         if (FIELD_DIFFERS(interface_version))
 125                 return True;
 126
 127         if (FIELD_DIFFERS(sizeof_ntvfs_critical_sizes))
 128                 return True;
 129
 130         if (FIELD_DIFFERS(sizeof_ntvfs_context))
 131                 return True;
 132
 133         if (FIELD_DIFFERS(sizeof_ntvfs_module_context))
 134                 return True;
 135
 136         if (FIELD_DIFFERS(sizeof_ntvfs_ops))
 137                 return True;
 138
 139         if (FIELD_DIFFERS(sizeof_ntvfs_async_state))
 140                 return True;
 141
 142         if (FIELD_DIFFERS(sizeof_ntvfs_request))
 143                 return True;
 144
 145         /* Versions match. */
 146         return False;
 147
 148 #undef FIELD_DIFFERS
 149 }
 150
 151 /*
 152   initialise a connection structure to point at a NTVFS backend
 153 */
 154 NTSTATUS ntvfs_init_connection(TALLOC_CTX *mem_ctx, struct share_config *scfg, enum ntvfs_type type,
 155                                enum protocol_types protocol,
 156                                struct event_context *ev, struct messaging_context *msg,
 157                                struct server_id server_id, struct ntvfs_context **_ctx)
 158 {
 159         const char **handlers = share_string_list_option(mem_ctx, scfg, SHARE_NTVFS_HANDLER);
 160         int i;
 161         struct ntvfs_context *ctx;
 162
 163         if (!handlers) {
 164                 return NT_STATUS_INTERNAL_ERROR;
 165         }
 166
 167         ctx = talloc_zero(mem_ctx, struct ntvfs_context);
 168         NT_STATUS_HAVE_NO_MEMORY(ctx);
 169         ctx->protocol           = protocol;
 170         ctx->type               = type;
 171         ctx->config             = talloc_steal(ctx, scfg);
 172         ctx->event_ctx          = ev;
 173         ctx->msg_ctx            = msg;
 174         ctx->server_id          = server_id;
 175
 176         for (i=0; handlers[i]; i++) {
 177                 struct ntvfs_module_context *ntvfs;
 178
 179                 ntvfs = talloc_zero(ctx, struct ntvfs_module_context);
 180                 NT_STATUS_HAVE_NO_MEMORY(ntvfs);
 181                 ntvfs->ctx = ctx;
 182                 ntvfs->ops = ntvfs_backend_byname(handlers[i], ctx->type);
 183                 if (!ntvfs->ops) {
 184                         DEBUG(1,("ntvfs_init_connection: failed to find backend=%s, type=%d\n",
 185                                 handlers[i], ctx->type));
 186                         return NT_STATUS_INTERNAL_ERROR;
 187                 }
 188                 ntvfs->depth = i;
 189                 DLIST_ADD_END(ctx->modules, ntvfs, struct ntvfs_module_context *);
 190         }
 191
 192         if (!ctx->modules) {
 193                 return NT_STATUS_INTERNAL_ERROR;
 194         }
 195
 196         *_ctx = ctx;
 197         return NT_STATUS_OK;
 198 }
 199
 200 NTSTATUS ntvfs_init(void)
 201 {
 202         init_module_fn static_init[] = STATIC_ntvfs_MODULES;
 203         init_module_fn *shared_init = load_samba_modules(NULL, "ntvfs");
 204
 205         run_init_functions(static_init);
 206         run_init_functions(shared_init);
 207
 208         talloc_free(shared_init);
 209
 210         return NT_STATUS_OK;
 211 }