source4/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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /*
  21   abstract the various kernel interfaces to change notify into a
  22   single Samba friendly interface
  23 */
  24
  25 #include "includes.h"
  26 #include "system/filesys.h"
  27 #include "ntvfs/sysdep/sys_notify.h"
  28 #include <tevent.h>
  29 #include "../lib/util/dlinklist.h"
  30 #include "param/param.h"
  31 #include "lib/util/samba_modules.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 tevent_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                 return NULL;
  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                 char *enable_opt_name;
  76                 bool enabled;
  77
  78                 enable_opt_name = talloc_asprintf(mem_ctx, "notify:%s",
  79                                                                                   backends[i].name);
  80                 enabled = share_bool_option(scfg, enable_opt_name, true);
  81                 talloc_free(enable_opt_name);
  82
  83                 if (!enabled)
  84                         continue;
  85
  86                 if (strcasecmp(backends[i].name, bname) == 0) {
  87                         bname = backends[i].name;
  88                         break;
  89                 }
  90         }
  91
  92         ctx->name = bname;
  93         ctx->notify_watch = NULL;
  94
  95         if (i < num_backends) {
  96                 ctx->notify_watch = backends[i].notify_watch;
  97         }
  98
  99         return ctx;
 100 }
 101
 102 /*
 103   add a watch
 104
 105   note that this call must modify the e->filter and e->subdir_filter
 106   bits to remove ones handled by this backend. Any remaining bits will
 107   be handled by the generic notify layer
 108 */
 109 _PUBLIC_ NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 110                                    struct notify_entry *e,
 111                                    sys_notify_callback_t callback,
 112                                    void *private_data, void *handle)
 113 {
 114         if (!ctx->notify_watch) {
 115                 return NT_STATUS_INVALID_SYSTEM_SERVICE;
 116         }
 117         return ctx->notify_watch(ctx, e, callback, private_data, handle);
 118 }
 119
 120 /*
 121   register a notify backend
 122 */
 123 _PUBLIC_ NTSTATUS sys_notify_register(struct sys_notify_backend *backend)
 124 {
 125         struct sys_notify_backend *b;
 126         b = talloc_realloc(talloc_autofree_context(), backends,
 127                            struct sys_notify_backend, num_backends+1);
 128         NT_STATUS_HAVE_NO_MEMORY(b);
 129         backends = b;
 130         backends[num_backends] = *backend;
 131         num_backends++;
 132         return NT_STATUS_OK;
 133 }
 134
 135 _PUBLIC_ NTSTATUS sys_notify_init(void)
 136 {
 137         static bool initialized = false;
 138 #define _MODULE_PROTO(init) extern NTSTATUS init(void);
 139         STATIC_sys_notify_MODULES_PROTO;
 140         init_module_fn static_init[] = { STATIC_sys_notify_MODULES };
 141
 142         if (initialized) return NT_STATUS_OK;
 143         initialized = true;
 144
 145         run_init_functions(static_init);
 146
 147         return NT_STATUS_OK;
 148 }