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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright 2018 Red Hat, Inc.
*/
#include <elf.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
#if __GLIBC_PREREQ(2, 16)
#include <sys/auxv.h>
#define HAS_AUXV 1
#endif
#endif
#include <rte_cpuflags.h>
#ifndef HAS_AUXV
static unsigned long
getauxval(unsigned long type __rte_unused)
{
errno = ENOTSUP;
return 0;
}
#endif
#ifdef RTE_ARCH_64
typedef Elf64_auxv_t Internal_Elfx_auxv_t;
#else
typedef Elf32_auxv_t Internal_Elfx_auxv_t;
#endif
/**
* Provides a method for retrieving values from the auxiliary vector and
* possibly running a string comparison.
*
* @return Always returns a result. When the result is 0, check errno
* to see if an error occurred during processing.
*/
static unsigned long
_rte_cpu_getauxval(unsigned long type, const char *str)
{
unsigned long val;
errno = 0;
val = getauxval(type);
if (!val && (errno == ENOTSUP || errno == ENOENT)) {
int auxv_fd = open("/proc/self/auxv", O_RDONLY);
Internal_Elfx_auxv_t auxv;
if (auxv_fd == -1)
return 0;
errno = ENOENT;
while (read(auxv_fd, &auxv, sizeof(auxv)) == sizeof(auxv)) {
if (auxv.a_type == type) {
errno = 0;
val = auxv.a_un.a_val;
if (str)
val = strcmp((const char *)val, str);
break;
}
}
close(auxv_fd);
}
return val;
}
unsigned long
rte_cpu_getauxval(unsigned long type)
{
return _rte_cpu_getauxval(type, NULL);
}
int
rte_cpu_strcmp_auxval(unsigned long type, const char *str)
{
return _rte_cpu_getauxval(type, str);
}
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