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/*
* 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;
static const ElfW_auxv_t *qemu_init_auxval(void)
{
ElfW_auxv_t *a;
ssize_t size = 512, r, ofs;
int fd;
/* Allocate some initial storage. Make sure the first entry is set
to end-of-list, so that we've got a valid list in case of error. */
auxv = a = g_malloc(size);
a[0].a_type = 0;
a[0].a_val = 0;
fd = open("/proc/self/auxv", O_RDONLY);
if (fd < 0) {
return a;
}
/* Read the first SIZE bytes. Hopefully, this covers everything. */
r = read(fd, a, size);
if (r == size) {
/* Continue to expand until we do get a partial read. */
do {
ofs = size;
size *= 2;
auxv = a = g_realloc(a, size);
r = read(fd, (char *)a + ofs, ofs);
} while (r == ofs);
}
close(fd);
return a;
}
unsigned long qemu_getauxval(unsigned long type)
{
const ElfW_auxv_t *a = auxv;
if (unlikely(a == NULL)) {
a = qemu_init_auxval();
}
for (; a->a_type != 0; a++) {
if (a->a_type == type) {
return a->a_val;
}
}
return 0;
}
#endif
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