freebsd-dev/lib/libc/gen/aux.c
Konstantin Belousov a7d61fc17d Fetch the aux vector for the static libc, and use the entries to
initialize the cache of the system information as it was done for the
dynamic libc. This removes several sysctls from the static binary
startup.

Use the aux vector to fill the single struct dl_phdr_info describing
the static binary itself, to implement dl_iterate_phdr(3) for the
static binaries. [1]

Based on the submission by:	John Marino <draco marino st> [1]
Tested by:   flo (sparc64)
MFC after:	2 weeks
2012-02-17 10:49:29 +00:00

172 lines
3.8 KiB
C

/*-
* Copyright 2010, 2012 Konstantin Belousov <kib@FreeBSD.ORG>.
* 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 ``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 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.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <elf.h>
#include <errno.h>
#include <link.h>
#include <pthread.h>
#include <string.h>
#include "un-namespace.h"
#include "libc_private.h"
extern char **environ;
extern int _DYNAMIC;
#pragma weak _DYNAMIC
void *__elf_aux_vector;
static pthread_once_t aux_vector_once = PTHREAD_ONCE_INIT;
static void
init_aux_vector_once(void)
{
Elf_Addr *sp;
sp = (Elf_Addr *)environ;
while (*sp++ != 0)
;
__elf_aux_vector = (Elf_Auxinfo *)sp;
}
void
__init_elf_aux_vector(void)
{
if (&_DYNAMIC != NULL)
return;
_once(&aux_vector_once, init_aux_vector_once);
}
static pthread_once_t aux_once = PTHREAD_ONCE_INIT;
static int pagesize, osreldate, canary_len, ncpus, pagesizes_len;
static char *canary, *pagesizes;
static void
init_aux(void)
{
Elf_Auxinfo *aux;
for (aux = __elf_aux_vector; aux->a_type != AT_NULL; aux++) {
switch (aux->a_type) {
case AT_CANARY:
canary = (char *)(aux->a_un.a_ptr);
break;
case AT_CANARYLEN:
canary_len = aux->a_un.a_val;
break;
case AT_PAGESIZES:
pagesizes = (char *)(aux->a_un.a_ptr);
break;
case AT_PAGESIZESLEN:
pagesizes_len = aux->a_un.a_val;
break;
case AT_PAGESZ:
pagesize = aux->a_un.a_val;
break;
case AT_OSRELDATE:
osreldate = aux->a_un.a_val;
break;
case AT_NCPUS:
ncpus = aux->a_un.a_val;
break;
}
}
}
int
_elf_aux_info(int aux, void *buf, int buflen)
{
int res;
__init_elf_aux_vector();
if (__elf_aux_vector == NULL)
return (ENOSYS);
_once(&aux_once, init_aux);
switch (aux) {
case AT_CANARY:
if (canary != NULL && canary_len >= buflen) {
memcpy(buf, canary, buflen);
memset(canary, 0, canary_len);
canary = NULL;
res = 0;
} else
res = ENOENT;
break;
case AT_PAGESIZES:
if (pagesizes != NULL && pagesizes_len >= buflen) {
memcpy(buf, pagesizes, buflen);
res = 0;
} else
res = ENOENT;
break;
case AT_PAGESZ:
if (buflen == sizeof(int)) {
if (pagesize != 0) {
*(int *)buf = pagesize;
res = 0;
} else
res = ENOENT;
} else
res = EINVAL;
break;
case AT_OSRELDATE:
if (buflen == sizeof(int)) {
if (osreldate != 0) {
*(int *)buf = osreldate;
res = 0;
} else
res = ENOENT;
} else
res = EINVAL;
break;
case AT_NCPUS:
if (buflen == sizeof(int)) {
if (ncpus != 0) {
*(int *)buf = ncpus;
res = 0;
} else
res = ENOENT;
} else
res = EINVAL;
break;
default:
res = ENOENT;
break;
}
return (res);
}