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 "../lib/tevent/tevent.h"
  29 #include "../lib/util/dlinklist.h"
  30 #include "param/param.h"
  31
  32 /* list of registered backends */
  33 static struct sys_notify_backend *backends;
  34 static uint32_t num_backends;
  35
  36 #define NOTIFY_BACKEND  "notify:backend"
  37
  38 /*
  39   initialise a system change notify backend
  40 */
  41 _PUBLIC_ struct sys_notify_context *sys_notify_context_create(struct share_config *scfg,
  42                                                               TALLOC_CTX *mem_ctx,
  43                                                               struct tevent_context *ev)
  44 {
  45         struct sys_notify_context *ctx;
  46         const char *bname;
  47         int i;
  48
  49         if (num_backends == 0) {
  50                 return NULL;
  51         }
  52
  53         if (ev == NULL) {
  54                 return NULL;
  55         }
  56
  57         ctx = talloc_zero(mem_ctx, struct sys_notify_context);
  58         if (ctx == NULL) {
  59                 return NULL;
  60         }
  61
  62         ctx->ev = ev;
  63
  64         bname = share_string_option(scfg, NOTIFY_BACKEND, NULL);
  65         if (!bname) {
  66                 if (num_backends) {
  67                         bname = backends[0].name;
  68                 } else {
  69                         bname = "__unknown__";
  70                 }
  71         }
  72
  73         for (i=0;i<num_backends;i++) {
  74                 char *enable_opt_name;
  75                 bool enabled;
  76
  77                 enable_opt_name = talloc_asprintf(mem_ctx, "notify:%s",
  78                                                                                   backends[i].name);
  79                 enabled = share_bool_option(scfg, enable_opt_name, true);
  80                 talloc_free(enable_opt_name);
  81
  82                 if (!enabled)
  83                         continue;
  84
  85                 if (strcasecmp(backends[i].name, bname) == 0) {
  86                         bname = backends[i].name;
  87                         break;
  88                 }
  89         }
  90
  91         ctx->name = bname;
  92         ctx->notify_watch = NULL;
  93
  94         if (i < num_backends) {
  95                 ctx->notify_watch = backends[i].notify_watch;
  96         }
  97
  98         return ctx;
  99 }
 100
 101 /*
 102   add a watch
 103
 104   note that this call must modify the e->filter and e->subdir_filter
 105   bits to remove ones handled by this backend. Any remaining bits will
 106   be handled by the generic notify layer
 107 */
 108 _PUBLIC_ NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 109                                    struct notify_entry *e,
 110                                    sys_notify_callback_t callback,
 111                                    void *private_data, void *handle)
 112 {
 113         if (!ctx->notify_watch) {
 114                 return NT_STATUS_INVALID_SYSTEM_SERVICE;
 115         }
 116         return ctx->notify_watch(ctx, e, callback, private_data, handle);
 117 }
 118
 119 /*
 120   register a notify backend
 121 */
 122 _PUBLIC_ NTSTATUS sys_notify_register(struct sys_notify_backend *backend)
 123 {
 124         struct sys_notify_backend *b;
 125         b = talloc_realloc(talloc_autofree_context(), backends,
 126                            struct sys_notify_backend, num_backends+1);
 127         NT_STATUS_HAVE_NO_MEMORY(b);
 128         backends = b;
 129         backends[num_backends] = *backend;
 130         num_backends++;
 131         return NT_STATUS_OK;
 132 }
 133
 134 _PUBLIC_ NTSTATUS sys_notify_init(void)
 135 {
 136         static bool initialized = false;
 137         extern NTSTATUS sys_notify_inotify_init(void);
 138
 139         init_module_fn static_init[] = { STATIC_sys_notify_MODULES };
 140
 141         if (initialized) return NT_STATUS_OK;
 142         initialized = true;
 143
 144         run_init_functions(static_init);
 145
 146         return NT_STATUS_OK;
 147 }