[libvirt] [PATCH 1/3] util: add virendian.h macros
Eric Blake
eblake at redhat.com
Tue Feb 12 00:07:39 UTC 2013
We have several cases where we need to read endian-dependent
data regardless of host endianness; rather than open-coding
these call sites, it will be nicer to funnel things through
a macro.
The virendian.h file can be expanded to add writer functions,
and/or 16-bit access patterns, if needed. Also, if we need
to turn things into a function to avoid multiple evaluations
of buf, that can be done later. But for now, a macro worked.
* src/util/virendian.h: New file.
* src/Makefile.am (UTIL_SOURCES): Ship it.
* tests/virendiantest.c: New test.
* tests/Makefile.am (test_programs, virendiantest_SOURCES): Run
the test.
* .gitignore: Ignore built file.
---
.gitignore | 1 +
src/Makefile.am | 1 +
src/util/virendian.h | 93 +++++++++++++++++++++++++++++++++++++++++++++
tests/Makefile.am | 8 +++-
tests/virendiantest.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 203 insertions(+), 2 deletions(-)
create mode 100644 src/util/virendian.h
create mode 100644 tests/virendiantest.c
diff --git a/.gitignore b/.gitignore
index 1670637..8afbf33 100644
--- a/.gitignore
+++ b/.gitignore
@@ -177,6 +177,7 @@
/tests/virbitmaptest
/tests/virbuftest
/tests/virdrivermoduletest
+/tests/virendiantest
/tests/virhashtest
/tests/virkeyfiletest
/tests/virlockspacetest
diff --git a/src/Makefile.am b/src/Makefile.am
index f6162df..d554aa1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -67,6 +67,7 @@ UTIL_SOURCES = \
util/virdbus.c util/virdbus.h \
util/virdnsmasq.c util/virdnsmasq.h \
util/virebtables.c util/virebtables.h \
+ util/virendian.h \
util/virerror.c util/virerror.h \
util/virevent.c util/virevent.h \
util/vireventpoll.c util/vireventpoll.h \
diff --git a/src/util/virendian.h b/src/util/virendian.h
new file mode 100644
index 0000000..eefe48c
--- /dev/null
+++ b/src/util/virendian.h
@@ -0,0 +1,93 @@
+/*
+ * virendian.h: aid for reading endian-specific data
+ *
+ * Copyright (C) 2013 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef __VIR_ENDIAN_H__
+# define __VIR_ENDIAN_H__
+
+# include "internal.h"
+
+/* The interfaces in this file are provided as macros for speed. */
+
+/**
+ * virReadBufInt64BE:
+ * @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
+ * evaluating buf must not have any side effects
+ *
+ * Read 8 bytes at BUF as a big-endian 64-bit number. Caller is
+ * responsible to avoid reading beyond array bounds.
+ */
+# define virReadBufInt64BE(buf) \
+ (((uint64_t)(uint8_t)((buf)[0]) << 56) | \
+ ((uint64_t)(uint8_t)((buf)[1]) << 48) | \
+ ((uint64_t)(uint8_t)((buf)[2]) << 40) | \
+ ((uint64_t)(uint8_t)((buf)[3]) << 32) | \
+ ((uint64_t)(uint8_t)((buf)[4]) << 24) | \
+ ((uint64_t)(uint8_t)((buf)[5]) << 16) | \
+ ((uint64_t)(uint8_t)((buf)[6]) << 8) | \
+ (uint64_t)(uint8_t)((buf)[7]))
+
+/**
+ * virReadBufInt64LE:
+ * @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
+ * evaluating buf must not have any side effects
+ *
+ * Read 8 bytes at BUF as a little-endian 64-bit number. Caller is
+ * responsible to avoid reading beyond array bounds.
+ */
+# define virReadBufInt64LE(buf) \
+ ((uint64_t)(uint8_t)((buf)[0]) | \
+ ((uint64_t)(uint8_t)((buf)[1]) << 8) | \
+ ((uint64_t)(uint8_t)((buf)[2]) << 16) | \
+ ((uint64_t)(uint8_t)((buf)[3]) << 24) | \
+ ((uint64_t)(uint8_t)((buf)[4]) << 32) | \
+ ((uint64_t)(uint8_t)((buf)[5]) << 40) | \
+ ((uint64_t)(uint8_t)((buf)[6]) << 48) | \
+ ((uint64_t)(uint8_t)((buf)[7]) << 56))
+
+/**
+ * virReadBufInt32BE:
+ * @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
+ * evaluating buf must not have any side effects
+ *
+ * Read 4 bytes at BUF as a big-endian 32-bit number. Caller is
+ * responsible to avoid reading beyond array bounds.
+ */
+# define virReadBufInt32BE(buf) \
+ (((uint32_t)(uint8_t)((buf)[0]) << 24) | \
+ ((uint32_t)(uint8_t)((buf)[1]) << 16) | \
+ ((uint32_t)(uint8_t)((buf)[2]) << 8) | \
+ (uint32_t)(uint8_t)((buf)[3]))
+
+/**
+ * virReadBufInt32LE:
+ * @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
+ * evaluating buf must not have any side effects
+ *
+ * Read 4 bytes at BUF as a little-endian 32-bit number. Caller is
+ * responsible to avoid reading beyond array bounds.
+ */
+# define virReadBufInt32LE(buf) \
+ ((uint32_t)(uint8_t)((buf)[0]) | \
+ ((uint32_t)(uint8_t)((buf)[1]) << 8) | \
+ ((uint32_t)(uint8_t)((buf)[2]) << 16) | \
+ ((uint32_t)(uint8_t)((buf)[3]) << 24))
+
+#endif /* __VIR_ENDIAN_H__ */
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 0194db2..7d0a88e 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,6 +1,6 @@
## Process this file with automake to produce Makefile.in
-## Copyright (C) 2005-2012 Red Hat, Inc.
+## Copyright (C) 2005-2013 Red Hat, Inc.
## See COPYING.LIB for the License of this software
SHELL = $(PREFERABLY_POSIX_SHELL)
@@ -95,7 +95,7 @@ test_programs = virshtest sockettest \
utiltest shunloadtest \
virtimetest viruritest virkeyfiletest \
virauthconfigtest \
- virbitmaptest \
+ virbitmaptest virendiantest \
virlockspacetest \
virstringtest \
virportallocatortest \
@@ -649,6 +649,10 @@ virbitmaptest_SOURCES = \
virbitmaptest.c testutils.h testutils.c
virbitmaptest_LDADD = $(LDADDS)
+virendiantest_SOURCES = \
+ virendiantest.c testutils.h testutils.c
+virendiantest_LDADD = $(LDADDS)
+
jsontest_SOURCES = \
jsontest.c testutils.h testutils.c
jsontest_LDADD = $(LDADDS)
diff --git a/tests/virendiantest.c b/tests/virendiantest.c
new file mode 100644
index 0000000..386ef33
--- /dev/null
+++ b/tests/virendiantest.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2013 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "testutils.h"
+
+#include "virendian.h"
+
+static int
+test1(const void *data ATTRIBUTE_UNUSED)
+{
+ /* Regular char should work, even if signed, and even with
+ * unaligned access. */
+ char array[] = { 1, 2, 3, 4, 5, 6, 7, 8,
+ 0x89, 0x8a, 0x8b, 0x8c, 0x8d };
+ int ret = -1;
+
+ if (virReadBufInt64BE(array) != 0x0102030405060708ULL)
+ goto cleanup;
+ if (virReadBufInt64BE(array + 5) != 0x060708898a8b8c8dULL)
+ goto cleanup;
+ if (virReadBufInt64LE(array) != 0x0807060504030201ULL)
+ goto cleanup;
+ if (virReadBufInt64LE(array + 5) != 0x8d8c8b8a89080706ULL)
+ goto cleanup;
+
+ if (virReadBufInt32BE(array) != 0x01020304U)
+ goto cleanup;
+ if (virReadBufInt32BE(array + 8) != 0x898a8b8cU)
+ goto cleanup;
+ if (virReadBufInt32LE(array) != 0x04030201U)
+ goto cleanup;
+ if (virReadBufInt32LE(array + 8) != 0x8c8b8a89U)
+ goto cleanup;
+
+ ret = 0;
+cleanup:
+ return ret;
+}
+
+static int
+test2(const void *data ATTRIBUTE_UNUSED)
+{
+ /* Unsigned char should work without cast, even if unaligned access. */
+ unsigned char array[] = { 1, 2, 3, 4, 5, 6, 7, 8,
+ 0x89, 0x8a, 0x8b, 0x8c, 0x8d };
+ int ret = -1;
+
+ if (virReadBufInt64BE(array) != 0x0102030405060708ULL)
+ goto cleanup;
+ if (virReadBufInt64BE(array + 5) != 0x060708898a8b8c8dULL)
+ goto cleanup;
+ if (virReadBufInt64LE(array) != 0x0807060504030201ULL)
+ goto cleanup;
+ if (virReadBufInt64LE(array + 5) != 0x8d8c8b8a89080706ULL)
+ goto cleanup;
+
+ if (virReadBufInt32BE(array) != 0x01020304U)
+ goto cleanup;
+ if (virReadBufInt32BE(array + 8) != 0x898a8b8cU)
+ goto cleanup;
+ if (virReadBufInt32LE(array) != 0x04030201U)
+ goto cleanup;
+ if (virReadBufInt32LE(array + 8) != 0x8c8b8a89U)
+ goto cleanup;
+
+ ret = 0;
+cleanup:
+ return ret;
+}
+
+static int
+mymain(void)
+{
+ int ret = 0;
+
+ if (virtTestRun("test1", 1, test1, NULL) < 0)
+ ret = -1;
+ if (virtTestRun("test2", 1, test2, NULL) < 0)
+ ret = -1;
+
+ return ret;
+}
+
+VIRT_TEST_MAIN(mymain)
--
1.8.1.2
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