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Revert "less sys calls #2: make vdso work again"

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alexey-milovidov 2021-08-19 01:38:12 +03:00 committed by GitHub
parent c6bcd48bee
commit 3db3b40b5e
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1 changed files with 12 additions and 37 deletions
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49
base/glibc-compatibility/musl/getauxval.c
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@ -1,5 +1,4 @@
#include <sys/auxv.h>
#include "atomic.h"
#include <unistd.h> // __environ
#include <errno.h>
@ -18,7 +17,18 @@ static size_t __find_auxv(unsigned long type)
return (size_t) -1;
}
unsigned long __getauxval(unsigned long type)
__attribute__((constructor)) static void __auxv_init()
{
size_t i;
for (i = 0; __environ[i]; i++);
__auxv = (unsigned long *) (__environ + i + 1);
size_t secure_idx = __find_auxv(AT_SECURE);
if (secure_idx != ((size_t) -1))
__auxv_secure = __auxv[secure_idx];
}
unsigned long getauxval(unsigned long type)
{
if (type == AT_SECURE)
return __auxv_secure;
@ -33,38 +43,3 @@ unsigned long __getauxval(unsigned long type)
errno = ENOENT;
return 0;
}
static void * volatile getauxval_func;
static unsigned long __auxv_init(unsigned long type)
{
if (!__environ)
{
// __environ is not initialized yet so we can't initialize __auxv right now.
// That's normally occurred only when getauxval() is called from some sanitizer's internal code.
errno = ENOENT;
return 0;
}
// Initialize __auxv and __auxv_secure.
size_t i;
for (i = 0; __environ[i]; i++);
__auxv = (unsigned long *) (__environ + i + 1);
size_t secure_idx = __find_auxv(AT_SECURE);
if (secure_idx != ((size_t) -1))
__auxv_secure = __auxv[secure_idx];
// Now we've initialized __auxv, next time getauxval() will only call __get_auxval().
a_cas_p(&getauxval_func, (void *)__auxv_init, (void *)__getauxval);
return __getauxval(type);
}
// First time getauxval() will call __auxv_init().
static void * volatile getauxval_func = (void *)__auxv_init;
unsigned long getauxval(unsigned long type)
{
return ((unsigned long (*)(unsigned long))getauxval_func)(type);
}