osdep: Create qemu_getauxval and qemu_init_auxval

Abstract away dependence on a system implementation of getauxval.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-06-04 11:24:49 -07:00
parent 7dc65c02fe
commit b6a3e690b4
5 changed files with 102 additions and 0 deletions

View file

@ -215,4 +215,29 @@ bool fips_get_state(void);
*/
char *qemu_get_local_state_pathname(const char *relative_pathname);
/**
* qemu_getauxval:
* @type: the auxiliary vector key to lookup
*
* Search the auxiliary vector for @type, returning the value
* or 0 if @type is not present.
*/
#if defined(CONFIG_GETAUXVAL) || defined(__linux__)
unsigned long qemu_getauxval(unsigned long type);
#else
static inline unsigned long qemu_getauxval(unsigned long type) { return 0; }
#endif
/**
* qemu_init_auxval:
* @envp: the third argument to main
*
* If supported and required, locate the auxiliary vector at program startup.
*/
#if defined(CONFIG_GETAUXVAL) || !defined(__linux__)
static inline void qemu_init_auxval(char **envp) { }
#else
void qemu_init_auxval(char **envp);
#endif
#endif

View file

@ -3701,6 +3701,7 @@ 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) {

View file

@ -12,3 +12,4 @@ util-obj-y += qemu-option.o qemu-progress.o
util-obj-y += hexdump.o
util-obj-y += crc32c.o
util-obj-y += throttle.o
util-obj-y += getauxval.o

74
util/getauxval.c Normal file
View file

@ -0,0 +1,74 @@
/*
* 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(__linux__)
#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)
{
/* The auxiliary vector is located just beyond the initial environment. */
while (*envp++ != NULL) {
continue;
}
auxv = (const ElfW_auxv_t *)envp;
}
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;
}
}
}
return 0;
}
#endif

1
vl.c
View file

@ -2894,6 +2894,7 @@ 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);