source3/smbd/notifyd/fcn_wait.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 3 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  14  */
  15
  16 #include "replace.h"
  17 #include "fcn_wait.h"
  18 #include "notifyd.h"
  19 #include "lib/util/tevent_ntstatus.h"
  20
  21 struct fcn_event {
  22         struct fcn_event *prev, *next;
  23         struct notify_event_msg msg;
  24 };
  25
  26 struct fcn_wait_state {
  27         struct tevent_context *ev;
  28         struct messaging_context *msg_ctx;
  29         struct server_id notifyd;
  30         const char *path;
  31
  32         struct tevent_req *recv_subreq;
  33
  34         struct fcn_event *events;
  35 };
  36
  37 static bool fcn_wait_cancel(struct tevent_req *req);
  38 static void fcn_wait_cleanup(
  39         struct tevent_req *req, enum tevent_req_state req_state);
  40 static bool fcn_wait_filter(struct messaging_rec *rec, void *private_data);
  41 static void fcn_wait_done(struct tevent_req *subreq);
  42
  43 struct tevent_req *fcn_wait_send(
  44         TALLOC_CTX *mem_ctx,
  45         struct tevent_context *ev,
  46         struct messaging_context *msg_ctx,
  47         struct server_id notifyd,
  48         const char *path,
  49         uint32_t filter,
  50         uint32_t subdir_filter)
  51 {
  52         struct tevent_req *req = NULL;
  53         struct fcn_wait_state *state = NULL;
  54         struct notify_rec_change_msg msg = {
  55                 .instance.filter = filter,
  56                 .instance.subdir_filter = subdir_filter,
  57         };
  58         struct iovec iov[2];
  59         NTSTATUS status;
  60
  61         req = tevent_req_create(mem_ctx, &state, struct fcn_wait_state);
  62         if (req == NULL) {
  63                 return NULL;
  64         }
  65         state->ev = ev;
  66         state->msg_ctx = msg_ctx;
  67         state->notifyd = notifyd;
  68         state->path = path;
  69
  70         state->recv_subreq = messaging_filtered_read_send(
  71                 state, ev, msg_ctx, fcn_wait_filter, req);
  72         if (tevent_req_nomem(state->recv_subreq, req)) {
  73                 return tevent_req_post(req, ev);
  74         }
  75         tevent_req_set_callback(state->recv_subreq, fcn_wait_done, req);
  76         tevent_req_set_cleanup_fn(req, fcn_wait_cleanup);
  77
  78         clock_gettime_mono(&msg.instance.creation_time);
  79         msg.instance.private_data = state;
  80
  81         iov[0].iov_base = &msg;
  82         iov[0].iov_len = offsetof(struct notify_rec_change_msg, path);
  83         iov[1].iov_base = discard_const_p(char, path);
  84         iov[1].iov_len = strlen(path)+1;
  85
  86         status = messaging_send_iov(
  87                 msg_ctx,                        /* msg_ctx */
  88                 notifyd,                        /* dst */
  89                 MSG_SMB_NOTIFY_REC_CHANGE,      /* mst_type */
  90                 iov,                            /* iov */
  91                 ARRAY_SIZE(iov),                /* iovlen */
  92                 NULL,                           /* fds */
  93                 0);                             /* num_fds */
  94         if (tevent_req_nterror(req, status)) {
  95                 DBG_DEBUG("messaging_send_iov failed: %s\n",
  96                           nt_errstr(status));
  97                 return tevent_req_post(req, ev);
  98         }
  99         tevent_req_set_cancel_fn(req, fcn_wait_cancel);
 100
 101         return req;
 102 }
 103
 104 static bool fcn_wait_cancel(struct tevent_req *req)
 105 {
 106         struct fcn_wait_state *state = tevent_req_data(
 107                 req, struct fcn_wait_state);
 108         struct notify_rec_change_msg msg = {
 109                 .instance.filter = 0, /* filter==0 is a delete msg */
 110                 .instance.subdir_filter = 0,
 111         };
 112         struct iovec iov[2];
 113         NTSTATUS status;
 114
 115         clock_gettime_mono(&msg.instance.creation_time);
 116         msg.instance.private_data = state;
 117
 118         iov[0].iov_base = &msg;
 119         iov[0].iov_len = offsetof(struct notify_rec_change_msg, path);
 120         iov[1].iov_base = discard_const_p(char, state->path);
 121         iov[1].iov_len = strlen(state->path)+1;
 122
 123         status = messaging_send_iov(
 124                 state->msg_ctx,                 /* msg_ctx */
 125                 state->notifyd,                 /* dst */
 126                 MSG_SMB_NOTIFY_REC_CHANGE,      /* mst_type */
 127                 iov,                            /* iov */
 128                 ARRAY_SIZE(iov),                /* iovlen */
 129                 NULL,                           /* fds */
 130                 0);                             /* num_fds */
 131         if (!NT_STATUS_IS_OK(status)) {
 132                 DBG_DEBUG("messaging_send_iov failed: %s\n",
 133                           nt_errstr(status));
 134                 return false;
 135         }
 136
 137         fcn_wait_cleanup(req, 0); /* fcn_wait_cleanup ignores req_state */
 138         tevent_req_defer_callback(req, state->ev);
 139         tevent_req_nterror(req, NT_STATUS_CANCELLED);
 140
 141         return true;
 142 }
 143
 144 static void fcn_wait_cleanup(
 145         struct tevent_req *req, enum tevent_req_state req_state)
 146 {
 147         struct fcn_wait_state *state = tevent_req_data(
 148                 req, struct fcn_wait_state);
 149         TALLOC_FREE(state->recv_subreq);
 150 }
 151
 152 static bool fcn_wait_filter(struct messaging_rec *rec, void *private_data)
 153 {
 154         struct tevent_req *req = talloc_get_type_abort(
 155                 private_data, struct tevent_req);
 156         struct fcn_wait_state *state = tevent_req_data(
 157                 req, struct fcn_wait_state);
 158         struct notify_event_msg msg = { .action = 0 };
 159         struct fcn_event *evt = NULL;
 160
 161         if (rec->msg_type != MSG_PVFS_NOTIFY) {
 162                 DBG_DEBUG("Ignoring msg %"PRIu32"\n", rec->msg_type);
 163                 return false;
 164         }
 165
 166         /*
 167          * We need at least the trailing '\0' for the path
 168          */
 169         if (rec->buf.length < (offsetof(struct notify_event_msg, path) + 1)) {
 170                 DBG_DEBUG("Ignoring short (%zu) msg\n", rec->buf.length);
 171                 return false;
 172         }
 173         if (rec->buf.data[rec->buf.length-1] != '\0') {
 174                 DBG_DEBUG("Expected 0-terminated path\n");
 175                 return false;
 176         }
 177
 178         memcpy(&msg, rec->buf.data, sizeof(msg));
 179
 180         if (msg.private_data != state) {
 181                 DBG_DEBUG("Got private_data=%p, expected %p\n",
 182                           msg.private_data,
 183                           state);
 184                 return false;
 185         }
 186
 187         evt = talloc_memdup(state, rec->buf.data, rec->buf.length);
 188         if (evt == NULL) {
 189                 DBG_DEBUG("talloc_memdup failed\n");
 190                 return false;
 191         }
 192         talloc_set_name_const(evt, "struct fcn_event");
 193
 194         /*
 195          * TODO: Sort by timestamp
 196          */
 197
 198         DLIST_ADD_END(state->events, evt);
 199
 200         tevent_req_defer_callback(req, state->ev);
 201         tevent_req_notify_callback(req);
 202
 203         return false;
 204 }
 205
 206 static void fcn_wait_done(struct tevent_req *subreq)
 207 {
 208         struct tevent_req *req = tevent_req_callback_data(
 209                 subreq, struct tevent_req);
 210         int ret;
 211
 212         ret = messaging_filtered_read_recv(subreq, NULL, NULL);
 213         TALLOC_FREE(subreq);
 214         if (ret != 0) {
 215                 DBG_DEBUG("messaging_filtered_read failed: %s\n",
 216                           strerror(ret));
 217                 tevent_req_nterror(req, map_nt_error_from_unix(ret));
 218                 return;
 219         }
 220
 221         /*
 222          * We should never have gotten here, all work is done from the
 223          * filter function.
 224          */
 225         tevent_req_nterror(req, NT_STATUS_INTERNAL_ERROR);
 226 }
 227
 228 NTSTATUS fcn_wait_recv(
 229         struct tevent_req *req,
 230         TALLOC_CTX *mem_ctx,
 231         struct timespec *when,
 232         uint32_t *action,
 233         char **path)
 234 {
 235         struct fcn_wait_state *state = tevent_req_data(
 236                 req, struct fcn_wait_state);
 237         struct fcn_event *evt = NULL;
 238         NTSTATUS status;
 239
 240         if (!tevent_req_is_in_progress(req) &&
 241             tevent_req_is_nterror(req, &status)) {
 242                 return status;
 243         }
 244         evt = state->events;
 245         if (evt == NULL) {
 246                 return NT_STATUS_RETRY;
 247         }
 248
 249         if (path != NULL) {
 250                 *path = talloc_strdup(mem_ctx, evt->msg.path);
 251                 if ((*path) == NULL) {
 252                         return NT_STATUS_NO_MEMORY;
 253                 }
 254         }
 255         if (when != NULL) {
 256                 *when = evt->msg.when;
 257         }
 258         if (action != NULL) {
 259                 *action = evt->msg.action;
 260         }
 261
 262         DLIST_REMOVE(state->events, evt);
 263
 264         if (state->events != NULL) {
 265                 tevent_req_defer_callback(req, state->ev);
 266                 tevent_req_notify_callback(req);
 267         }
 268
 269         return NT_STATUS_OK;
 270 }