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Revert "Linux: Consolidate auxiliary vector parsing"

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This reverts commit 8c8510ab27.  The
revert is not perfect because the commit included a bug fix for
_dl_sysdep_start with an empty argv, introduced in commit
2d47fa6862 ("Linux: Remove
DL_FIND_ARG_COMPONENTS"), and this bug fix is kept.

The revert is necessary because the reverted commit introduced an
early memset call on aarch64, which leads to crash due to lack of TCB
initialization.
This commit is contained in:
Florian Weimer
2022-02-11 16:01:19 +01:00
parent 02561bb48a
commit d96d2995c1
6 changed files with 180 additions and 106 deletions
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109
sysdeps/unix/sysv/linux/dl-sysdep.c
View File

@ -21,12 +21,13 @@
#include <dl-auxv.h>
#include <dl-hwcap-check.h>
#include <dl-osinfo.h>
#include <dl-parse_auxv.h>
#include <dl-procinfo.h>
#include <dl-tunables.h>
#include <elf.h>
#include <entry.h>
#include <errno.h>
#include <fcntl.h>
#include <fpu_control.h>
#include <ldsodefs.h>
#include <libc-internal.h>
#include <libintl.h>
@ -62,20 +63,20 @@ void *_dl_random attribute_relro = NULL;
# define DL_STACK_END(cookie) ((void *) (cookie))
#endif
/* Arguments passed to dl_main. */
struct dl_main_arguments
ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
{
const ElfW(Phdr) *phdr;
ElfW(Word) phnum;
const ElfW(Phdr) *phdr = NULL;
ElfW(Word) phnum = 0;
ElfW(Addr) user_entry;
};
ElfW(auxv_t) *av;
#ifdef NEED_DL_SYSINFO
uintptr_t new_sysinfo = 0;
#endif
/* Separate function, so that dl_main can be called without the large
array on the stack. */
static void
_dl_sysdep_parse_arguments (void **start_argptr,
struct dl_main_arguments *args)
{
__libc_stack_end = DL_STACK_END (start_argptr);
_dl_argc = (intptr_t) *start_argptr;
_dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */
_environ = _dl_argv + _dl_argc + 1;
@ -87,26 +88,75 @@ _dl_sysdep_parse_arguments (void **start_argptr,
break;
}
dl_parse_auxv_t auxv_values = { 0, };
_dl_parse_auxv (GLRO(dl_auxv), auxv_values);
user_entry = (ElfW(Addr)) ENTRY_POINT;
GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */
args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR];
args->phnum = auxv_values[AT_PHNUM];
args->user_entry = auxv_values[AT_ENTRY];
}
/* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */
_Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
"CONSTANT_MINSIGSTKSZ is constant");
GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
{
__libc_stack_end = DL_STACK_END (start_argptr);
struct dl_main_arguments dl_main_args;
_dl_sysdep_parse_arguments (start_argptr, &dl_main_args);
for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
switch (av->a_type)
{
case AT_PHDR:
phdr = (void *) av->a_un.a_val;
break;
case AT_PHNUM:
phnum = av->a_un.a_val;
break;
case AT_PAGESZ:
GLRO(dl_pagesize) = av->a_un.a_val;
break;
case AT_ENTRY:
user_entry = av->a_un.a_val;
break;
case AT_SECURE:
__libc_enable_secure = av->a_un.a_val;
break;
case AT_PLATFORM:
GLRO(dl_platform) = (void *) av->a_un.a_val;
break;
case AT_HWCAP:
GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
break;
case AT_HWCAP2:
GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
break;
case AT_CLKTCK:
GLRO(dl_clktck) = av->a_un.a_val;
break;
case AT_FPUCW:
GLRO(dl_fpu_control) = av->a_un.a_val;
break;
#ifdef NEED_DL_SYSINFO
case AT_SYSINFO:
new_sysinfo = av->a_un.a_val;
break;
#endif
case AT_SYSINFO_EHDR:
GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
break;
case AT_RANDOM:
_dl_random = (void *) av->a_un.a_val;
break;
case AT_MINSIGSTKSZ:
GLRO(dl_minsigstacksize) = av->a_un.a_val;
break;
DL_PLATFORM_AUXV
}
dl_hwcap_check ();
#ifdef NEED_DL_SYSINFO
if (new_sysinfo != 0)
{
/* Only set the sysinfo value if we also have the vsyscall DSO. */
if (GLRO(dl_sysinfo_dso) != 0)
GLRO(dl_sysinfo) = new_sysinfo;
}
#endif
__tunables_init (_environ);
/* Initialize DSO sorting algorithm after tunables. */
@ -137,9 +187,8 @@ _dl_sysdep_start (void **start_argptr,
if (__builtin_expect (__libc_enable_secure, 0))
__libc_check_standard_fds ();
(*dl_main) (dl_main_args.phdr, dl_main_args.phnum,
&dl_main_args.user_entry, GLRO(dl_auxv));
return dl_main_args.user_entry;
(*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
return user_entry;
}
void