tsocket: add tstream_readv_pdu_send/recv()

[samba.git] / lib / tsocket / tsocket_helpers.c

diff --git a/lib/tsocket/tsocket_helpers.c b/lib/tsocket/tsocket_helpers.c
index 1876dc3882f75f67d173dcf9b7fadfd049f3f7ea..1b9a9bf6708f2a60a5c05b0bbc96f30b1a860dc6 100644 (file)
--- a/lib/tsocket/tsocket_helpers.c
+++ b/lib/tsocket/tsocket_helpers.c
@@ -22,6 +22,7 @@
 */
 
 #include "replace.h"
+#include "system/filesys.h"
 #include "tsocket.h"
 #include "tsocket_internal.h"
 
@@ -155,3 +156,167 @@ ssize_t tdgram_sendto_queue_recv(struct tevent_req *req, int *perrno)
        return ret;
 }
 
+struct tstream_readv_pdu_state {
+       /* this structs are owned by the caller */
+       struct {
+               struct tevent_context *ev;
+               struct tstream_context *stream;
+               tstream_readv_pdu_next_vector_t next_vector_fn;
+               void *next_vector_private;
+       } caller;
+
+       /*
+        * Each call to the callback resets iov and count
+        * the callback allocated the iov as child of our state,
+        * that means we are allowed to modify and free it.
+        *
+        * we should call the callback every time we filled the given
+        * vector and ask for a new vector. We return if the callback
+        * ask for 0 bytes.
+        */
+       struct iovec *vector;
+       size_t count;
+
+       /*
+        * the total number of bytes we read,
+        * the return value of the _recv function
+        */
+       int total_read;
+};
+
+static void tstream_readv_pdu_ask_for_next_vector(struct tevent_req *req);
+static void tstream_readv_pdu_readv_done(struct tevent_req *subreq);
+
+struct tevent_req *tstream_readv_pdu_send(TALLOC_CTX *mem_ctx,
+                               struct tevent_context *ev,
+                               struct tstream_context *stream,
+                               tstream_readv_pdu_next_vector_t next_vector_fn,
+                               void *next_vector_private)
+{
+       struct tevent_req *req;
+       struct tstream_readv_pdu_state *state;
+
+       req = tevent_req_create(mem_ctx, &state,
+                               struct tstream_readv_pdu_state);
+       if (!req) {
+               return NULL;
+       }
+
+       state->caller.ev                        = ev;
+       state->caller.stream                    = stream;
+       state->caller.next_vector_fn            = next_vector_fn;
+       state->caller.next_vector_private       = next_vector_private;
+
+       state->vector           = NULL;
+       state->count            = 0;
+       state->total_read       = 0;
+
+       tstream_readv_pdu_ask_for_next_vector(req);
+       if (!tevent_req_is_in_progress(req)) {
+               goto post;
+       }
+
+       return req;
+
+ post:
+       return tevent_req_post(req, ev);
+}
+
+static void tstream_readv_pdu_ask_for_next_vector(struct tevent_req *req)
+{
+       struct tstream_readv_pdu_state *state = tevent_req_data(req,
+                                           struct tstream_readv_pdu_state);
+       int ret;
+       size_t to_read = 0;
+       size_t i;
+       struct tevent_req *subreq;
+
+       TALLOC_FREE(state->vector);
+       state->count = 0;
+
+       ret = state->caller.next_vector_fn(state->caller.stream,
+                                          state->caller.next_vector_private,
+                                          state, &state->vector, &state->count);
+       if (ret == -1) {
+               tevent_req_error(req, errno);
+               return;
+       }
+
+       if (state->count == 0) {
+               tevent_req_done(req);
+               return;
+       }
+
+       for (i=0; i < state->count; i++) {
+               size_t tmp = to_read;
+               tmp += state->vector[i].iov_len;
+
+               if (tmp < to_read) {
+                       tevent_req_error(req, EMSGSIZE);
+                       return;
+               }
+
+               to_read = tmp;
+       }
+
+       /*
+        * this is invalid the next vector function should have
+        * reported count == 0.
+        */
+       if (to_read == 0) {
+               tevent_req_error(req, EINVAL);
+               return;
+       }
+
+       if (state->total_read + to_read < state->total_read) {
+               tevent_req_error(req, EMSGSIZE);
+               return;
+       }
+
+       subreq = tstream_readv_send(state,
+                                   state->caller.ev,
+                                   state->caller.stream,
+                                   state->vector,
+                                   state->count);
+       if (tevent_req_nomem(subreq, req)) {
+               return;
+       }
+       tevent_req_set_callback(subreq, tstream_readv_pdu_readv_done, req);
+}
+
+static void tstream_readv_pdu_readv_done(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(subreq,
+                                struct tevent_req);
+       struct tstream_readv_pdu_state *state = tevent_req_data(req,
+                                           struct tstream_readv_pdu_state);
+       int ret;
+       int sys_errno;
+
+       ret = tstream_readv_recv(subreq, &sys_errno);
+       if (ret == -1) {
+               tevent_req_error(req, sys_errno);
+               return;
+       }
+
+       state->total_read += ret;
+
+       /* ask the callback for a new vector we should fill */
+       tstream_readv_pdu_ask_for_next_vector(req);
+}
+
+int tstream_readv_pdu_recv(struct tevent_req *req, int *perrno)
+{
+       struct tstream_readv_pdu_state *state = tevent_req_data(req,
+                                           struct tstream_readv_pdu_state);
+       int ret;
+
+       ret = tsocket_simple_int_recv(req, perrno);
+       if (ret == 0) {
+               ret = state->total_read;
+       }
+
+       tevent_req_received(req);
+       return ret;
+}
+