[DTrace-devel] [PATCH v2 2/3] Restore order of bcopy() arg evaluations
eugene.loh at oracle.com
eugene.loh at oracle.com
Sat Feb 18 00:50:35 UTC 2023
From: Eugene Loh <eugene.loh at oracle.com>
In c26e2e5f279a ("Add support for copyinto() subroutine"), the order
of arg evaluations for bcopy() was changed from evaluating the last
arg (size) last to evaluating it first. This has semantic implications
when the order of arguments matters.
Restore the previous order (to agree with Solaris semantics) and add
tests for both bcopy() and copyinto().
Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
---
libdtrace/dt_cg.c | 15 +++--
.../funcs/bcopy/tst.bcopy_arg_order.d | 52 +++++++++++++++++
.../funcs/bcopy/tst.bcopy_arg_order.r | 3 +
.../funcs/copyinto/tst.copyinto_arg_order.d | 57 +++++++++++++++++++
.../funcs/copyinto/tst.copyinto_arg_order.r | 5 ++
5 files changed, 128 insertions(+), 4 deletions(-)
create mode 100644 test/unittest/funcs/bcopy/tst.bcopy_arg_order.d
create mode 100644 test/unittest/funcs/bcopy/tst.bcopy_arg_order.r
create mode 100644 test/unittest/funcs/copyinto/tst.copyinto_arg_order.d
create mode 100644 test/unittest/funcs/copyinto/tst.copyinto_arg_order.r
diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
index 53d969d5..44209a05 100644
--- a/libdtrace/dt_cg.c
+++ b/libdtrace/dt_cg.c
@@ -4514,18 +4514,25 @@ dt_cg_subr_bcopy_impl(dt_node_t *dnp, dt_node_t *dst, dt_node_t *src,
TRACE_REGSET(" subr-bcopy-impl:Begin");
- /* Validate the size for the copy operation. */
- dt_cg_node(size, dlp, drp);
+ /* Evaluate the arguments */
+ if (is_bcopy) {
+ dt_cg_node(src, dlp, drp);
+ dt_cg_node(dst, dlp, drp);
+ dt_cg_node(size, dlp, drp);
+ } else {
+ dt_cg_node(src, dlp, drp);
+ dt_cg_node(size, dlp, drp);
+ dt_cg_node(dst, dlp, drp);
+ }
+ /* Validate the size for the copy operation. */
emit(dlp, BPF_BRANCH_IMM(BPF_JSLT, size->dn_reg, 0, lbl_badsize));
emit(dlp, BPF_BRANCH_IMM(BPF_JGT, size->dn_reg, maxsize, lbl_badsize));
/* Validate the source pointer. */
- dt_cg_node(src, dlp, drp);
dt_cg_check_ptr_arg(dlp, drp, src, size);
/* Validate the destination pointer. */
- dt_cg_node(dst, dlp, drp);
if (!(dst->dn_flags & DT_NF_ALLOCA))
dnerror(dst, D_PROTO_ARG,
"%s( ) argument #%d is incompatible with prototype:\n"
diff --git a/test/unittest/funcs/bcopy/tst.bcopy_arg_order.d b/test/unittest/funcs/bcopy/tst.bcopy_arg_order.d
new file mode 100644
index 00000000..4c213931
--- /dev/null
+++ b/test/unittest/funcs/bcopy/tst.bcopy_arg_order.d
@@ -0,0 +1,52 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: Arguments are evaluated in the correct order.
+ *
+ * SECTION: Actions and Subroutines/bcopy()
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+ src = (char *)alloca(8);
+ dst = (char *)alloca(8);
+
+ /* initialize src */
+ src[ 0] = 'a'; src[ 1] = 'b'; src[ 2] = 'c'; src[ 3] = 'd';
+ src[ 4] = 'e'; src[ 5] = 'f'; src[ 6] = 'g'; src[ 7] = 'h';
+
+ /* initialize dst with '.' */
+ dst[ 0] = dst[ 1] = dst[ 2] = dst[ 3] =
+ dst[ 4] = dst[ 5] = dst[ 6] = dst[ 7] = '.';
+
+ /* execute subroutine with order-dependent arguments */
+ n = 2;
+ bcopy((void*)(src + (n++)), (void*)(dst + (n++)), (n++));
+
+ /* print results */
+ printf("%c%c%c%c%c%c%c%c\n",
+ dst[ 0], dst[ 1], dst[ 2], dst[ 3],
+ dst[ 4], dst[ 5], dst[ 6], dst[ 7]);
+
+ /* repeat all that but with order-independent arguments */
+ dst[ 0] = dst[ 1] = dst[ 2] = dst[ 3] =
+ dst[ 4] = dst[ 5] = dst[ 6] = dst[ 7] = '.';
+ bcopy((void*)(src + 2), (void*)(dst + 3), 4);
+ printf("%c%c%c%c%c%c%c%c\n",
+ dst[ 0], dst[ 1], dst[ 2], dst[ 3],
+ dst[ 4], dst[ 5], dst[ 6], dst[ 7]);
+
+ exit(0);
+}
+
+ERROR
+{
+ exit(1);
+}
diff --git a/test/unittest/funcs/bcopy/tst.bcopy_arg_order.r b/test/unittest/funcs/bcopy/tst.bcopy_arg_order.r
new file mode 100644
index 00000000..11db2dd4
--- /dev/null
+++ b/test/unittest/funcs/bcopy/tst.bcopy_arg_order.r
@@ -0,0 +1,3 @@
+...cdef.
+...cdef.
+
diff --git a/test/unittest/funcs/copyinto/tst.copyinto_arg_order.d b/test/unittest/funcs/copyinto/tst.copyinto_arg_order.d
new file mode 100644
index 00000000..a5a7b504
--- /dev/null
+++ b/test/unittest/funcs/copyinto/tst.copyinto_arg_order.d
@@ -0,0 +1,57 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: Arguments are evaluated in the correct order.
+ *
+ * SECTION: Actions and Subroutines/copyinto()
+ */
+/* @@trigger: delaydie */
+
+#pragma D option quiet
+
+syscall::write:entry
+/pid == $target/
+{
+ ptr = (char *)alloca(16);
+
+ /* initialize with '.' */
+ ptr[ 0] = ptr[ 1] = ptr[ 2] = ptr[ 3] =
+ ptr[ 4] = ptr[ 5] = ptr[ 6] = ptr[ 7] =
+ ptr[ 8] = ptr[ 9] = ptr[10] = ptr[11] =
+ ptr[12] = ptr[13] = ptr[14] = ptr[15] = '.';
+
+ /* execute subroutine with order-dependent arguments */
+ n = 2;
+ copyinto(arg1 + (n++), (n++), (void*)(ptr + (n++)));
+
+ /* print results */
+ printf("%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c\n",
+ ptr[ 0], ptr[ 1], ptr[ 2], ptr[ 3],
+ ptr[ 4], ptr[ 5], ptr[ 6], ptr[ 7],
+ ptr[ 8], ptr[ 9], ptr[10], ptr[11],
+ ptr[12], ptr[13], ptr[14], ptr[15]);
+
+ /* repeat all that but with order-independent arguments */
+ ptr[ 0] = ptr[ 1] = ptr[ 2] = ptr[ 3] =
+ ptr[ 4] = ptr[ 5] = ptr[ 6] = ptr[ 7] =
+ ptr[ 8] = ptr[ 9] = ptr[10] = ptr[11] =
+ ptr[12] = ptr[13] = ptr[14] = ptr[15] = '.';
+ copyinto(arg1 + 2, 3, (void *)(ptr + 4));
+ printf("%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c\n",
+ ptr[ 0], ptr[ 1], ptr[ 2], ptr[ 3],
+ ptr[ 4], ptr[ 5], ptr[ 6], ptr[ 7],
+ ptr[ 8], ptr[ 9], ptr[10], ptr[11],
+ ptr[12], ptr[13], ptr[14], ptr[15]);
+
+ exit(0);
+}
+
+ERROR
+{
+ exit(1);
+}
diff --git a/test/unittest/funcs/copyinto/tst.copyinto_arg_order.r b/test/unittest/funcs/copyinto/tst.copyinto_arg_order.r
new file mode 100644
index 00000000..e2bd6295
--- /dev/null
+++ b/test/unittest/funcs/copyinto/tst.copyinto_arg_order.r
@@ -0,0 +1,5 @@
+....lay.........
+....lay.........
+
+-- @@stderr --
+Delay in ns needed in delay env var.
--
2.18.4
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