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Make elf_aux_info() as public libc function.

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- Teach elf aux vector functions about newly added AT_HWCAP and AT_HWCAP2
  vectors.
- Export _elf_aux_info() as new public libc function elf_aux_info(3)

The elf_aux_info(3) should be considered as FreeBSD counterpart of glibc
getauxval() with more robust interface.

Note:
We cannot name this new function as getauxval(), with glibc compatible
interface. Some ports autodetect its existence and then expects that all
Linux specific AT_<*> vectors are defined and implemented.

MFC after:	1 month
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D12743
This commit is contained in:
Michal Meloun 2017-10-21 12:06:18 +00:00
parent 904d8c492f
commit 0b08ae2120
3 changed files with 67 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
lib/libc/gen/Symbol.map
View File

@ -398,6 +398,7 @@ FBSD_1.5 {
devname;
devname_r;
dirname;
elf_aux_info;
fts_children;
fts_close;
fts_get_clientptr;

30
lib/libc/gen/auxv.c
View File

@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
#include <link.h>
#include <pthread.h>
#include <string.h>
#include <sys/auxv.h>
#include "un-namespace.h"
#include "libc_private.h"
@ -65,8 +66,10 @@ __init_elf_aux_vector(void)
static pthread_once_t aux_once = PTHREAD_ONCE_INIT;
static int pagesize, osreldate, canary_len, ncpus, pagesizes_len;
static int hwcap_present, hwcap2_present;
static char *canary, *pagesizes;
static void *timekeep;
static u_long hwcap, hwcap2;
static void
init_aux(void)
@ -83,6 +86,16 @@ init_aux(void)
canary_len = aux->a_un.a_val;
break;
case AT_HWCAP:
hwcap_present = 1;
hwcap = (u_long)(aux->a_un.a_val);
break;
case AT_HWCAP2:
hwcap2_present = 1;
hwcap2 = (u_long)(aux->a_un.a_val);
break;
case AT_PAGESIZES:
pagesizes = (char *)(aux->a_un.a_ptr);
break;
@ -110,6 +123,8 @@ init_aux(void)
}
}
__weak_reference(_elf_aux_info, elf_aux_info);
int
_elf_aux_info(int aux, void *buf, int buflen)
{
@ -130,6 +145,20 @@ _elf_aux_info(int aux, void *buf, int buflen)
} else
res = ENOENT;
break;
case AT_HWCAP:
if (hwcap_present && buflen == sizeof(u_long)) {
*(u_long *)buf = hwcap;
res = 0;
} else
res = ENOENT;
break;
case AT_HWCAP2:
if (hwcap2_present && buflen == sizeof(u_long)) {
*(u_long *)buf = hwcap2;
res = 0;
} else
res = ENOENT;
break;
case AT_PAGESIZES:
if (pagesizes != NULL && pagesizes_len >= buflen) {
memcpy(buf, pagesizes, buflen);
@ -137,7 +166,6 @@ _elf_aux_info(int aux, void *buf, int buflen)
} else
res = ENOENT;
break;
case AT_PAGESZ:
if (buflen == sizeof(int)) {
if (pagesize != 0) {

37
sys/sys/auxv.h Normal file
View File

@ -0,0 +1,37 @@
/*-
* Copyright (c) 2017 Michal Meloun
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SYS_AUXV_H_
#define _SYS_AUXV_H_
#include <sys/types.h>
#include <machine/elf.h>
int elf_aux_info(int aux, void *buf, int buflen);
#endif /* !_SYS_AUXV_H_ */