Abstract away dependence on a system implementation of getauxval.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
include/qemu/osdep.h | 20 ++++++++++++
linux-user/main.c | 1 +
util/Makefile.objs | 1 +
util/getauxval.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++
vl.c | 1 +
5 files changed, 114 insertions(+)
create mode 100644 util/getauxval.c
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 26136f1..8d1948b 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -215,4 +215,24 @@ bool fips_get_state(void);
*/
char *qemu_get_local_state_pathname(const char *relative_pathname);
+/* Return a value for an AT_* type in the auxiliary vector. Return 0 if the
+ * key is not present. We attempt to emulate AT_HWCAP and AT_PLATFORM as
+ * best we can when real host support is not present.
+ */
+#ifdef _WIN32
+static inline unsigned long qemu_getauxval(unsigned long type) { return 0; }
+#else
+unsigned long qemu_getauxval(unsigned long type);
+#endif
+
+/* If supported and required, locate the auxiliary vector at program startup.
+ *
+ * @envp must be the third argument to main.
+ */
+#if defined(CONFIG_GETAUXVAL) || defined(_WIN32)
+static inline void qemu_init_auxval(char **envp) { }
+#else
+void qemu_init_auxval(char **envp);
+#endif
+
#endif
diff --git a/linux-user/main.c b/linux-user/main.c
index 5c2f7b2..ebd9cf4 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3553,6 +3553,7 @@ int main(int argc, char **argv, char **envp)
module_call_init(MODULE_INIT_QOM);
+ qemu_init_auxval(envp);
qemu_cache_utils_init(envp);
if ((envlist = envlist_create()) == NULL) {
diff --git a/util/Makefile.objs b/util/Makefile.objs
index dc72ab0..8e0c929 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -11,3 +11,4 @@ util-obj-y += iov.o aes.o qemu-config.o qemu-sockets.o uri.o
notify.o
util-obj-y += qemu-option.o qemu-progress.o
util-obj-y += hexdump.o
util-obj-y += crc32c.o
+util-obj-y += getauxval.o
diff --git a/util/getauxval.c b/util/getauxval.c
new file mode 100644
index 0000000..59f53ff
--- /dev/null
+++ b/util/getauxval.c
@@ -0,0 +1,91 @@
+/*
+ * QEMU access to the auxiliary vector
+ *
+ * Copyright (C) 2013 Red Hat, Inc
+ *
+ * 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-common.h"
+#include "qemu/osdep.h"
+
+#ifdef CONFIG_GETAUXVAL
+/* Don't inline this in qemu/osdep.h, because pulling in <sys/auxv.h> for
+ the system declaration of getauxval pulls in the system <elf.h>, which
+ conflicts with qemu's version. */
+
+#include <sys/auxv.h>
+
+unsigned long qemu_getauxval(unsigned long key)
+{
+ return getauxval(key);
+}
+#elif !defined(_WIN32)
+#include "elf.h"
+
+/* Our elf.h doesn't contain Elf32_auxv_t and Elf64_auxv_t, which is ok because
+ that just makes it easier to define it properly for the host here. */
+typedef struct {
+ unsigned long a_type;
+ unsigned long a_val;
+} ElfW_auxv_t;
+
+static const ElfW_auxv_t *auxv;
+
+void qemu_init_auxval(char **envp)
+{
+#ifdef __linux__
+ /* The auxiliary vector is located just beyond the initial environment. */
+ while (*envp++ != NULL)
+ continue;
+ auxv = (const ElfW_auxv_t *)envp;
+#endif
+}
+
+static const char *default_platform(void)
+{
+ return NULL;
+}
+
+static unsigned long default_hwcap(void)
+{
+ return 0;
+}
+
+unsigned long qemu_getauxval(unsigned long type)
+{
+ /* If we were able to find the auxiliary vector, use it. */
+ if (auxv) {
+ const ElfW_auxv_t *a;
+ for (a = auxv; a->a_type != 0; a++) {
+ if (a->a_type == type) {
+ return a->a_val;
+ }
+ }
+ }
+
+ /* Otherwise, guess defaults for the host based on compiler flags. */
+ if (type == AT_HWCAP) {
+ return default_hwcap();
+ } else if (type == AT_PLATFORM) {
+ return (unsigned long)default_platform();
+ }
+ return 0;
+}
+#endif
diff --git a/vl.c b/vl.c
index b4b119a..35eff6a 100644
--- a/vl.c
+++ b/vl.c
@@ -2967,6 +2967,7 @@ int main(int argc, char **argv, char **envp)
init_clocks();
rtc_clock = QEMU_CLOCK_HOST;
+ qemu_init_auxval(envp);
qemu_cache_utils_init(envp);
QLIST_INIT (&vm_change_state_head);
--
1.8.1.4
