source/ntvfs/sysdep/sys_notify.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Copyright (C) Andrew Tridgell 2006
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /*
  22   abstract the various kernel interfaces to change notify into a
  23   single Samba friendly interface
  24 */
  25
  26 #include "includes.h"
  27 #include "system/filesys.h"
  28 #include "ntvfs/sysdep/sys_notify.h"
  29 #include "lib/events/events.h"
  30 #include "lib/util/dlinklist.h"
  31 #include "build.h"
  32
  33 /* list of registered backends */
  34 static struct sys_notify_backend *backends;
  35 static uint32_t num_backends;
  36
  37 #define NOTIFY_BACKEND  "notify-backend"
  38
  39 /*
  40   initialise a system change notify backend
  41 */
  42 _PUBLIC_ struct sys_notify_context *sys_notify_context_create(struct share_config *scfg,
  43                                                               TALLOC_CTX *mem_ctx,
  44                                                               struct event_context *ev)
  45 {
  46         struct sys_notify_context *ctx;
  47         const char *bname;
  48         int i;
  49
  50         if (num_backends == 0) {
  51                 return NULL;
  52         }
  53
  54         if (ev == NULL) {
  55                 ev = event_context_find(mem_ctx);
  56         }
  57
  58         ctx = talloc_zero(mem_ctx, struct sys_notify_context);
  59         if (ctx == NULL) {
  60                 return NULL;
  61         }
  62
  63         ctx->ev = ev;
  64
  65         bname = share_string_option(scfg, NOTIFY_BACKEND, NULL);
  66         if (!bname) {
  67                 if (num_backends) {
  68                         bname = backends[0].name;
  69                 } else {
  70                         bname = "__unknown__";
  71                 }
  72         }
  73
  74         for (i=0;i<num_backends;i++) {
  75                 if (strcasecmp(backends[i].name, bname) == 0) {
  76                         bname = backends[i].name;
  77                         break;
  78                 }
  79         }
  80
  81         ctx->name = bname;
  82         ctx->notify_watch = NULL;
  83
  84         if (i < num_backends) {
  85                 ctx->notify_watch = backends[i].notify_watch;
  86         }
  87
  88         return ctx;
  89 }
  90
  91 /*
  92   add a watch
  93
  94   note that this call must modify the e->filter and e->subdir_filter
  95   bits to remove ones handled by this backend. Any remaining bits will
  96   be handled by the generic notify layer
  97 */
  98 _PUBLIC_ NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
  99                                    struct notify_entry *e,
 100                                    sys_notify_callback_t callback,
 101                                    void *private_data, void *handle)
 102 {
 103         if (!ctx->notify_watch) {
 104                 return NT_STATUS_INVALID_SYSTEM_SERVICE;
 105         }
 106         return ctx->notify_watch(ctx, e, callback, private_data, handle);
 107 }
 108
 109 /*
 110   register a notify backend
 111 */
 112 _PUBLIC_ NTSTATUS sys_notify_register(struct sys_notify_backend *backend)
 113 {
 114         struct sys_notify_backend *b;
 115         b = talloc_realloc(talloc_autofree_context(), backends,
 116                            struct sys_notify_backend, num_backends+1);
 117         NT_STATUS_HAVE_NO_MEMORY(b);
 118         backends = b;
 119         backends[num_backends] = *backend;
 120         num_backends++;
 121         return NT_STATUS_OK;
 122 }
 123
 124 _PUBLIC_ NTSTATUS sys_notify_init(void)
 125 {
 126         static BOOL initialized = False;
 127
 128         init_module_fn static_init[] = STATIC_sys_notify_MODULES;
 129         init_module_fn *shared_init;
 130
 131         if (initialized) return NT_STATUS_OK;
 132         initialized = True;
 133
 134         shared_init = load_samba_modules(NULL, "sys_notify");
 135
 136         run_init_functions(static_init);
 137         run_init_functions(shared_init);
 138
 139         talloc_free(shared_init);
 140
 141         return NT_STATUS_OK;
 142 }