From: Georg Kotheimer <georg.kothei...@kernkonzept.com>
Previously the getauxval implementation was limited to the auxiliary
vector entries cached in _dl_auxvt. To also support entries outside of
that cached subset, store the start address of the auxiliary vector,
and if an uncached entry type is encountered search the entire auxiliary
vector.
Signed-off-by: Marcus Haehnel <marcus.haeh...@kernkonzept.com>
---
ldso/include/ldso.h | 3 ++-
ldso/ldso/dl-startup.c | 4 ++++
libc/misc/auxvt/getauxval.c | 30 +++++++++++++-----------------
libc/misc/elf/dl-support.c | 3 +++
4 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/ldso/include/ldso.h b/ldso/include/ldso.h
index a397cce61..60e0a5bec 100755
--- a/ldso/include/ldso.h
+++ b/ldso/include/ldso.h
@@ -192,7 +192,8 @@ extern void *_dl_get_ready_to_run(struct elf_resolve *tpnt,
DL_LOADADDR_TYPE loa
#endif
#define AUX_MAX_AT_ID 40
-extern ElfW(auxv_t) _dl_auxvt[AUX_MAX_AT_ID];
+extern ElfW(auxv_t) _dl_auxvt[AUX_MAX_AT_ID]; /* Cache frequently accessed
auxiliary vector entries */
+extern ElfW(auxv_t) *_dl_auxv_start; /* Start of the auxiliary vector
*/
void load_vdso(void *sys_info_ehdr, char **envp );
diff --git a/ldso/ldso/dl-startup.c b/ldso/ldso/dl-startup.c
index e7000bd87..e0d8c8fff 100644
--- a/ldso/ldso/dl-startup.c
+++ b/ldso/ldso/dl-startup.c
@@ -100,6 +100,7 @@ extern ElfW(Addr) _begin[] attribute_hidden;
ElfW(auxv_t) _dl_auxvt[AUX_MAX_AT_ID];
+ElfW(auxv_t) *_dl_auxv_start;
#ifdef LDSO_NEED_DPNT
ElfW(Dyn) *_dl_saved_dpnt = 0;
@@ -131,6 +132,7 @@ DL_START(unsigned long args)
struct elf_resolve tpnt_tmp;
struct elf_resolve *tpnt = &tpnt_tmp;
ElfW(auxv_t) _dl_auxvt_tmp[AUX_MAX_AT_ID];
+ ElfW(auxv_t) *_dl_auxv_start_tmp;
ElfW(Dyn) *dpnt;
uint32_t *p32;
@@ -166,6 +168,7 @@ DL_START(unsigned long args)
/* The junk on the stack immediately following the environment is
* the Auxiliary Vector Table. Read out the elements of the auxvt,
* sort and store them in auxvt for later use. */
+ _dl_auxv_start_tmp = (ElfW(auxv_t) *)aux_dat;
while (*aux_dat) {
ElfW(auxv_t) *auxv_entry = (ElfW(auxv_t) *) aux_dat;
@@ -367,6 +370,7 @@ DL_START(unsigned long args)
* now the globals work. so copy the aux vector
*/
_dl_memcpy( _dl_auxvt, _dl_auxvt_tmp, sizeof( ElfW(auxv_t) ) *
AUX_MAX_AT_ID );
+ _dl_auxv_start = _dl_auxv_start_tmp;
_dl_elf_main = (int (*)(int, char **, char **))
_dl_get_ready_to_run(tpnt, load_addr, envp, argv
diff --git a/libc/misc/auxvt/getauxval.c b/libc/misc/auxvt/getauxval.c
index 2bdffaf2c..7610b7e5c 100755
--- a/libc/misc/auxvt/getauxval.c
+++ b/libc/misc/auxvt/getauxval.c
@@ -17,32 +17,28 @@
* <http://www.gnu.org/licenses/>.
*/
-#include "errno.h"
-#include "ldso.h"
-#include "sys/auxv.h"
+#include <errno.h>
+#include <ldso.h>
+#include <sys/auxv.h>
-
-/*
- *
- * aarch64 gcc 11 uses __getauxval() in init_have_lse_atomics()
- *
- */
unsigned long int __getauxval (unsigned long int __type)
{
- if ( __type >= AUX_MAX_AT_ID ){
+ // Requested value part of cached subset of auxiliary vector?
+ if (__type < AUX_MAX_AT_ID) {
+ if (_dl_auxvt[__type].a_type == __type)
+ return _dl_auxvt[__type].a_un.a_val;
+
__set_errno (ENOENT);
return 0;
}
- if ( _dl_auxvt[__type].a_type == __type){
- return _dl_auxvt[__type].a_un.a_val;
- }
+ // Otherwise we have to iterate the auxiliary vector.
+ for (ElfW(auxv_t) *entry = _dl_auxv_start; entry->a_type != AT_NULL;
entry++)
+ if (entry->a_type == __type)
+ return entry->a_un.a_val;
__set_errno (ENOENT);
return 0;
}
-unsigned long int getauxval (unsigned long int __type){
- return __getauxval( __type );
-}
-
+weak_alias(__getauxval, getauxval)
diff --git a/libc/misc/elf/dl-support.c b/libc/misc/elf/dl-support.c
index 81c78fa55..09cbefc18 100644
--- a/libc/misc/elf/dl-support.c
+++ b/libc/misc/elf/dl-support.c
@@ -33,10 +33,13 @@ size_t _dl_phnum;
size_t _dl_pagesize;
ElfW(auxv_t) _dl_auxvt[AUX_MAX_AT_ID];
+ElfW(auxv_t) *_dl_auxv_start;
void internal_function _dl_aux_init (ElfW(auxv_t) *av);
void internal_function _dl_aux_init (ElfW(auxv_t) *av)
{
+ _dl_auxv_start = av;
+
memset(_dl_auxvt, 0x00, sizeof(_dl_auxvt));
for (; av->a_type != AT_NULL; av++)
{
--
2.47.1
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