rpc: Add tstream_u32_read

In npa_tstream.c we have two next_vector functions reading a big
endian uin32_t length and then the blob described by the length. This
factors that next_vector out into a central routine.

Why? I'll add another NPA protocol in the future, and this would add
yet another two copies of that next_vector code

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

diff --git a/libcli/named_pipe_auth/tstream_u32_read.c b/libcli/named_pipe_auth/tstream_u32_read.c
new file mode 100644 (file)
index 0000000..c8e95ef
--- /dev/null
+++ b/libcli/named_pipe_auth/tstream_u32_read.c
@@ -0,0 +1,159 @@
+/*
+ * Unix SMB/CIFS implementation.
+ *
+ * Copyright (C) Volker Lendecke 2019
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include "system/filesys.h"
+#include "tstream_u32_read.h"
+#include "lib/util/byteorder.h"
+#include "lib/util/tevent_unix.h"
+
+struct tstream_u32_read_state {
+       size_t max_msglen;
+       size_t buflen;
+       uint8_t *buf;
+};
+
+static int tstream_u32_read_next_vector(struct tstream_context *stream,
+                                       void *private_data,
+                                       TALLOC_CTX *mem_ctx,
+                                       struct iovec **_vector,
+                                       size_t *_count);
+static void tstream_u32_read_done(struct tevent_req *subreq);
+
+struct tevent_req *tstream_u32_read_send(
+       TALLOC_CTX *mem_ctx,
+       struct tevent_context *ev,
+       uint32_t max_msglen,
+       struct tstream_context *stream)
+{
+       struct tevent_req *req = NULL, *subreq = NULL;
+       struct tstream_u32_read_state *state = NULL;
+
+       req = tevent_req_create(
+               mem_ctx, &state, struct tstream_u32_read_state);
+       if (req == NULL) {
+               return NULL;
+       }
+       state->max_msglen = max_msglen;
+
+       subreq = tstream_readv_pdu_send(
+               state,
+               ev,
+               stream,
+               tstream_u32_read_next_vector,
+               state);
+       if (tevent_req_nomem(subreq, req)) {
+               return tevent_req_post(req, ev);
+       }
+       tevent_req_set_callback(subreq, tstream_u32_read_done, req);
+       return req;
+}
+
+static int tstream_u32_read_next_vector(struct tstream_context *stream,
+                                       void *private_data,
+                                       TALLOC_CTX *mem_ctx,
+                                       struct iovec **_vector,
+                                       size_t *_count)
+{
+       struct tstream_u32_read_state *state = talloc_get_type_abort(
+               private_data, struct tstream_u32_read_state);
+       size_t buflen = talloc_get_size(state->buf);
+       struct iovec *vector;
+       uint32_t msg_len;
+       size_t ofs = 0;
+       size_t count;
+
+       if (buflen == 0) {
+               msg_len = 4;
+               state->buf = talloc_array(state, uint8_t, msg_len);
+               if (state->buf == NULL) {
+                       return -1;
+               }
+       } else if (buflen == 4) {
+
+               ofs = 4;
+
+               msg_len = RIVAL(state->buf, 0);
+               if ((msg_len == 0) || (msg_len > state->max_msglen)) {
+                       errno = EMSGSIZE;
+                       return -1;
+               }
+               msg_len += ofs;
+               if (msg_len < ofs) {
+                       errno = EMSGSIZE;
+                       return -1;
+               }
+
+               state->buf = talloc_realloc(
+                       state, state->buf, uint8_t, msg_len);
+               if (state->buf == NULL) {
+                       return -1;
+               }
+       } else {
+               *_vector = NULL;
+               *_count = 0;
+               return 0;
+       }
+
+       vector = talloc(mem_ctx, struct iovec);
+       if (vector == NULL) {
+               return -1;
+       }
+       *vector = (struct iovec) {
+               .iov_base = state->buf + ofs, .iov_len = msg_len - ofs,
+       };
+       count = 1;
+
+       *_vector = vector;
+       *_count = count;
+       return 0;
+}
+
+static void tstream_u32_read_done(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       int ret, err;
+
+       ret = tstream_readv_pdu_recv(subreq, &err);
+       TALLOC_FREE(subreq);
+       if (ret == -1) {
+               tevent_req_error(req, err);
+               return;
+       }
+       tevent_req_done(req);
+}
+
+int tstream_u32_read_recv(
+       struct tevent_req *req,
+       TALLOC_CTX *mem_ctx,
+       uint8_t **buf,
+       size_t *buflen)
+{
+       struct tstream_u32_read_state *state = tevent_req_data(
+               req, struct tstream_u32_read_state);
+       int err;
+
+       if (tevent_req_is_unix_error(req, &err)) {
+               return err;
+       }
+       *buflen = talloc_get_size(state->buf);
+       *buf = talloc_move(mem_ctx, &state->buf);
+       return 0;
+}

diff --git a/libcli/named_pipe_auth/tstream_u32_read.h b/libcli/named_pipe_auth/tstream_u32_read.h
new file mode 100644 (file)
index 0000000..1356ff0
--- /dev/null
+++ b/libcli/named_pipe_auth/tstream_u32_read.h
@@ -0,0 +1,37 @@
+/*
+ * Unix SMB/CIFS implementation.
+ *
+ * Copyright (C) Volker Lendecke 2019
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TSTREAM_U32_READ_H
+#define TSTREAM_U32_READ_H
+
+#include "replace.h"
+#include "tsocket.h"
+
+struct tevent_req *tstream_u32_read_send(
+       TALLOC_CTX *mem_ctx,
+       struct tevent_context *ev,
+       uint32_t max_msglen,
+       struct tstream_context *stream);
+int tstream_u32_read_recv(
+       struct tevent_req *req,
+       TALLOC_CTX *mem_ctx,
+       uint8_t **buf,
+       size_t *buflen);
+
+#endif

diff --git a/libcli/named_pipe_auth/wscript_build b/libcli/named_pipe_auth/wscript_build
index 53fbd84ab6905de603dcf2f1e2ebed94167848dd..46986994b9da221c82a66dbbfda130d56349def0 100644 (file)
--- a/libcli/named_pipe_auth/wscript_build
+++ b/libcli/named_pipe_auth/wscript_build
@@ -2,7 +2,7 @@
 
 
 bld.SAMBA_LIBRARY('npa_tstream',
-                  source='npa_tstream.c',
+                  source='npa_tstream.c tstream_u32_read.c',
                   private_library=True,
                   public_deps='NDR_NAMED_PIPE_AUTH tevent LIBTSOCKET'
                   )