util: Unify implementations of qemu_memalign()

We implement qemu_memalign() in both oslib-posix.c and oslib-win32.c,
but the two versions are essentially the same: they call
qemu_try_memalign(), and abort() after printing an error message if
it fails.  The only difference is that the win32 version prints the
GetLastError() value whereas the POSIX version prints
strerror(errno).  However, this is a bug in the win32 version: in
commit dfbd0b8 in 2020 we changed the implementation of
qemu_try_memalign() from using VirtualAlloc() (which sets the
GetLastError() value) to using _aligned_malloc() (which sets errno),
but didn't update the error message to match.

Replace the two separate functions with a single version in a
new memalign.c file, which drops the unnecessary extra qemu_oom_check()
function and instead prints a more useful message including the
requested size and alignment as well as the errno string.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220226180723.1706285-4-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

util/memalign.c

@@ -0,0 +1,39 @@
+/*
+ * memalign.c: Allocate an aligned memory region
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2010-2016 Red Hat, Inc.
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+
+void *qemu_memalign(size_t alignment, size_t size)
+{
+    void *p = qemu_try_memalign(alignment, size);
+    if (p) {
+        return p;
+    }
+    fprintf(stderr,
+            "qemu_memalign: failed to allocate %zu bytes at alignment %zu: %s\n",
+            size, alignment, strerror(errno));
+    abort();
+}

util/meson.build

@@ -51,6 +51,7 @@ util_ss.add(when: 'CONFIG_POSIX', if_true: files('drm.c'))
 util_ss.add(files('guest-random.c'))
 util_ss.add(files('yank.c'))
 util_ss.add(files('int128.c'))
+util_ss.add(files('memalign.c'))
 
 if have_user
   util_ss.add(files('selfmap.c'))

util/oslib-posix.c

@@ -199,15 +199,6 @@ bool qemu_write_pidfile(const char *path, Error **errp)
     return false;
 }
 
-static void *qemu_oom_check(void *ptr)
-{
-    if (ptr == NULL) {
-        fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
-        abort();
-    }
-    return ptr;
-}
-
 void *qemu_try_memalign(size_t alignment, size_t size)
 {
     void *ptr;
@@ -234,11 +225,6 @@ void *qemu_try_memalign(size_t alignment, size_t size)
     return ptr;
 }
 
-void *qemu_memalign(size_t alignment, size_t size)
-{
-    return qemu_oom_check(qemu_try_memalign(alignment, size));
-}
-
 /* alloc shared memory pages */
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared,
                           bool noreserve)

util/oslib-win32.c

@@ -44,15 +44,6 @@
 /* this must come after including "trace.h" */
 #include <shlobj.h>
 
-static void *qemu_oom_check(void *ptr)
-{
-    if (ptr == NULL) {
-        fprintf(stderr, "Failed to allocate memory: %lu\n", GetLastError());
-        abort();
-    }
-    return ptr;
-}
-
 void *qemu_try_memalign(size_t alignment, size_t size)
 {
     void *ptr;
@@ -68,11 +59,6 @@ void *qemu_try_memalign(size_t alignment, size_t size)
     return ptr;
 }
 
-void *qemu_memalign(size_t alignment, size_t size)
-{
-    return qemu_oom_check(qemu_try_memalign(alignment, size));
-}
-
 static int get_allocation_granularity(void)
 {
     SYSTEM_INFO system_info;