r5797: - add idl property [subcontext_size()]

  this can be used like this
  [subcontext_size(28),subcontext(0)] dom_sid sid;

  this descripes a fixed 28 byte buffer which contains a dom_sid,
  and the rest of the buffer is padded with zero bytes if the dom_sid doesn't
  need all 28 byte in it's ndr encoding.

- only push and pull the subcontext when we are in the NDR_SCALARS section
  (tridge, jelmer: I hope this is correct for all cases...!?:-)

metze
(This used to be commit 483bb1418fd5c70c418142ade80c1e286adfa05a)

3 files changed, 74 insertions, 33 deletions

diff --git a/source4/build/pidl/ndr.pm b/source4/build/pidl/ndr.pm
index 0d021f8daa..fde9f05d2f 100644
--- a/source4/build/pidl/ndr.pm
+++ b/source4/build/pidl/ndr.pm
@@ -600,12 +600,12 @@ sub ParseArrayPull($$$$)
 	}
 }
 
-sub ParseSubcontextPushStart($)
+sub ParseSubcontextPushStart($$)
 {
 	my $e = shift;
-	my $sub_size = util::has_property($e, "subcontext");
+	my $ndr_flags = shift;
 
-	pidl "{";
+	pidl "if (($ndr_flags) & NDR_SCALARS) {";
 	indent;
 	pidl "struct ndr_push *_ndr_$e->{NAME};";
 	pidl "";
@@ -620,34 +620,48 @@ sub ParseSubcontextPushStart($)
 sub ParseSubcontextPushEnd($)
 {
 	my $e = shift;
-	my $sub_size = util::has_property($e, "subcontext");
-	pidl "NDR_CHECK(ndr_push_subcontext_header(ndr, $sub_size, _ndr_$e->{NAME}));";
+	my $header_size = util::has_property($e, "subcontext");
+	my $size_is = util::has_property($e, "subcontext_size");
+
+	if (not defined($size_is)) {
+		$size_is = "-1";
+	}
+
+	pidl "NDR_CHECK(ndr_push_subcontext_header(ndr, $header_size, $size_is, _ndr_$e->{NAME}));";
 	pidl "NDR_CHECK(ndr_push_bytes(ndr, _ndr_$e->{NAME}->data, _ndr_$e->{NAME}->offset));";
 	deindent;
 	pidl "}";
 }
 
-sub ParseSubcontextPullStart($)
+sub ParseSubcontextPullStart($$)
 {
 	my $e = shift;
-	my $sub_size = util::has_property($e, "subcontext");
+	my $ndr_flags = shift;	
+	my $header_size = util::has_property($e, "subcontext");
+	my $size_is = util::has_property($e, "subcontext_size");
 
-	pidl "{";
+	if (not defined($size_is)) {
+		$size_is = "-1";
+	}
+
+	pidl "if (($ndr_flags) & NDR_SCALARS) {";
 	indent;
 	pidl "struct ndr_pull *_ndr_$e->{NAME};";
 	pidl "NDR_ALLOC(ndr, _ndr_$e->{NAME});";
-	pidl "NDR_CHECK(ndr_pull_subcontext_header(ndr, $sub_size, _ndr_$e->{NAME}));"; 
-
+	pidl "NDR_CHECK(ndr_pull_subcontext_header(ndr, $header_size, $size_is, _ndr_$e->{NAME}));"; 
 	return "_ndr_$e->{NAME}";
 }
 
 sub ParseSubcontextPullEnd($)
 {
 	my $e = shift;
-	my $sub_size = util::has_property($e, "subcontext");
+	my $header_size = util::has_property($e, "subcontext");
+	my $size_is = util::has_property($e, "subcontext_size");
 
 	my $advance;
-	if ($sub_size) {
+	if (defined ($size_is)) {
+		$advance = "$size_is";	
+	} elsif ($header_size) {
 		$advance = "_ndr_$e->{NAME}->data_size";
 	} else {
 		$advance = "_ndr_$e->{NAME}->offset";
@@ -676,7 +690,7 @@ sub ParseElementPushScalar($$$)
 	}
 
 	if (defined $sub_size and $e->{POINTERS} == 0) {
-		$ndr = ParseSubcontextPushStart($e);
+		$ndr = ParseSubcontextPushStart($e, "NDR_SCALARS");
 	}
 
 	if (need_wire_pointer($e)) {
@@ -819,7 +833,7 @@ sub ParseElementPullScalar($$$)
 	start_flags($e);
 
 	if (defined $sub_size && $e->{POINTERS} == 0) {
-		$ndr = ParseSubcontextPullStart($e);
+		$ndr = ParseSubcontextPullStart($e, $ndr_flags);
 		$ndr_flags = "NDR_SCALARS|NDR_BUFFERS";
 	}
 
@@ -909,10 +923,10 @@ sub ParseElementPushBuffer($$)
 	}
 
 	if (defined $sub_size) {
-		$ndr = ParseSubcontextPushStart($e);
+		$ndr = ParseSubcontextPushStart($e, $ndr_flags);
 		$ndr_flags = "NDR_SCALARS|NDR_BUFFERS";
 	}
-	    
+
 	if (util::array_size($e)) {
 		ParseArrayPush($e, $ndr, "r->", $ndr_flags);
 	} else {
@@ -972,7 +986,7 @@ sub ParseElementPullBuffer($$)
 	}
 
 	if (defined $sub_size) {
-		$ndr = ParseSubcontextPullStart($e);
+		$ndr = ParseSubcontextPullStart($e, $ndr_flags);
 		$ndr_flags = "NDR_SCALARS|NDR_BUFFERS";
 	}
 
diff --git a/source4/build/pidl/validator.pm b/source4/build/pidl/validator.pm
index e8a42c6031..5e1f1e1660 100644
--- a/source4/build/pidl/validator.pm
+++ b/source4/build/pidl/validator.pm
@@ -72,6 +72,10 @@ sub ValidElement($)
 		fatal(el_name($e) . " : length_is() on non-array element");
 	}
 
+	if (defined (util::has_property($e, "subcontext_size")) and not defined(util::has_property($e, "subcontext"))) {
+		fatal(el_name($e) . " : subcontext_size() on non-subcontext element");
+	}
+
 	if (!$e->{POINTERS} && (
 		util::has_property($e, "ptr") or
 		util::has_property($e, "unique") or
diff --git a/source4/librpc/ndr/ndr.c b/source4/librpc/ndr/ndr.c
index b96a231a90..de8a01f5d5 100644
--- a/source4/librpc/ndr/ndr.c
+++ b/source4/librpc/ndr/ndr.c
@@ -433,34 +433,46 @@ NTSTATUS ndr_push_error(struct ndr_push *ndr, enum ndr_err_code err, const char
   we use magic in pidl to make them easier to cope with
 */
 NTSTATUS ndr_pull_subcontext_header(struct ndr_pull *ndr, 
-					   size_t sub_size,
+					   size_t header_size,
+					   ssize_t size_is,
 					   struct ndr_pull *ndr2)
 {
 	ndr2->flags = ndr->flags;
 
-	switch (sub_size) {
+	switch (header_size) {
 	case 0: {
-		uint32_t size = ndr->data_size - ndr->offset;
-		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, size));
+		uint32_t content_size = ndr->data_size - ndr->offset;
+		if (size_is >= 0) {
+			content_size = size_is;
+		}
+		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, content_size));
 		break;
 	}
 
 	case 2: {
-		uint16_t size;
-		NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &size));
-		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, size));
+		uint16_t content_size;
+		NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &content_size));
+		if (size_is >= 0 && size_is != content_size) {
+			return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) size_is(%d) mismatch content_size %d", 
+						size_is, content_size);
+		}
+		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, content_size));
 		break;
 	}
 
 	case 4: {
-		uint32_t size;
-		NDR_CHECK(ndr_pull_uint32(ndr, NDR_SCALARS, &size));
-		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, size));
+		uint32_t content_size;
+		NDR_CHECK(ndr_pull_uint32(ndr, NDR_SCALARS, &content_size));
+		if (size_is >= 0 && size_is != content_size) {
+			return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) size_is(%d) mismatch content_size %d", 
+						size_is, content_size);
+		}
+		NDR_CHECK(ndr_pull_subcontext(ndr, ndr2, content_size));
 		break;
 	}
 	default:
-		return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext size %d", 
-				      sub_size);
+		return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) header_size %d", 
+				      header_size);
 	}
 	return NT_STATUS_OK;
 }
@@ -469,10 +481,21 @@ NTSTATUS ndr_pull_subcontext_header(struct ndr_pull *ndr,
   push a subcontext header 
 */
 NTSTATUS ndr_push_subcontext_header(struct ndr_push *ndr, 
-					   size_t sub_size,
+					   size_t header_size,
+					   ssize_t size_is,
 					   struct ndr_push *ndr2)
 {
-	switch (sub_size) {
+	if (size_is >= 0) {
+		ssize_t padding_len = size_is - ndr2->offset;
+		if (padding_len > 0) {
+			NDR_CHECK(ndr_push_zero(ndr2, padding_len));
+		} else if (padding_len < 0) {
+			return ndr_push_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PUSH) content_size %d is larger than size_is(%d)",
+					      ndr2->offset, size_is);
+		}
+	}
+
+	switch (header_size) {
 	case 0: 
 		break;
 
@@ -485,8 +508,8 @@ NTSTATUS ndr_push_subcontext_header(struct ndr_push *ndr,
 		break;
 
 	default:
-		return ndr_push_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext size %d", 
-				      sub_size);
+		return ndr_push_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext header size %d", 
+				      header_size);
 	}
 	return NT_STATUS_OK;
 }