Revert "Linux: Consolidate auxiliary vector parsing"

This reverts commit 8c8510ab2790039e58995ef3a22309582413d3ff.  The
revert is not perfect because the commit included a bug fix for
_dl_sysdep_start with an empty argv, introduced in commit
2d47fa68628e831a692cba8fc9050cef435afc5e ("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.

6 files changed, 180 insertions, 106 deletions

diff --git a/elf/dl-support.c b/elf/dl-support.c
index 1977a2b..6d2c4ba 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -240,21 +240,93 @@ __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock)
 
 
 #ifdef HAVE_AUX_VECTOR
-#include <dl-parse_auxv.h>
-
 int _dl_clktck;
 
 void
 _dl_aux_init (ElfW(auxv_t) *av)
 {
+  int seen = 0;
+  uid_t uid = 0;
+  gid_t gid = 0;
+
 #ifdef NEED_DL_SYSINFO
   /* NB: Avoid RELATIVE relocation in static PIE.  */
   GL(dl_sysinfo) = DL_SYSINFO_DEFAULT;
 #endif
 
   _dl_auxv = av;
-  dl_parse_auxv_t auxv_values = { 0, };
-  _dl_parse_auxv (av, auxv_values);
+  for (; av->a_type != AT_NULL; ++av)
+    switch (av->a_type)
+      {
+      case AT_PAGESZ:
+	if (av->a_un.a_val != 0)
+	  GLRO(dl_pagesize) = av->a_un.a_val;
+	break;
+      case AT_CLKTCK:
+	GLRO(dl_clktck) = av->a_un.a_val;
+	break;
+      case AT_PHDR:
+	GL(dl_phdr) = (const void *) av->a_un.a_val;
+	break;
+      case AT_PHNUM:
+	GL(dl_phnum) = 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_FPUCW:
+	GLRO(dl_fpu_control) = av->a_un.a_val;
+	break;
+#ifdef NEED_DL_SYSINFO
+      case AT_SYSINFO:
+	GL(dl_sysinfo) = av->a_un.a_val;
+	break;
+#endif
+#ifdef NEED_DL_SYSINFO_DSO
+      case AT_SYSINFO_EHDR:
+	GL(dl_sysinfo_dso) = (void *) av->a_un.a_val;
+	break;
+#endif
+      case AT_UID:
+	uid ^= av->a_un.a_val;
+	seen |= 1;
+	break;
+      case AT_EUID:
+	uid ^= av->a_un.a_val;
+	seen |= 2;
+	break;
+      case AT_GID:
+	gid ^= av->a_un.a_val;
+	seen |= 4;
+	break;
+      case AT_EGID:
+	gid ^= av->a_un.a_val;
+	seen |= 8;
+	break;
+      case AT_SECURE:
+	seen = -1;
+	__libc_enable_secure = av->a_un.a_val;
+	__libc_enable_secure_decided = 1;
+	break;
+      case AT_RANDOM:
+	_dl_random = (void *) av->a_un.a_val;
+	break;
+      case AT_MINSIGSTKSZ:
+	_dl_minsigstacksize = av->a_un.a_val;
+	break;
+      DL_PLATFORM_AUXV
+      }
+  if (seen == 0xf)
+    {
+      __libc_enable_secure = uid != 0 || gid != 0;
+      __libc_enable_secure_decided = 1;
+    }
 }
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h
index fcec743..81d90da 100644
--- a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h
+++ b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h
@@ -20,8 +20,16 @@
 
 extern long __libc_alpha_cache_shape[4];
 
-#define DL_PLATFORM_AUXV					\
-  __libc_alpha_cache_shape[0] = auxv_values[AT_L1I_CACHESHAPE]; \
-  __libc_alpha_cache_shape[1] = auxv_values[AT_L1D_CACHESHAPE]; \
-  __libc_alpha_cache_shape[2] = auxv_values[AT_L2_CACHESHAPE];	\
-  __libc_alpha_cache_shape[3] = auxv_values[AT_L3_CACHESHAPE];
+#define DL_PLATFORM_AUXV				\
+      case AT_L1I_CACHESHAPE:				\
+	__libc_alpha_cache_shape[0] = av->a_un.a_val;	\
+	break;						\
+      case AT_L1D_CACHESHAPE:				\
+	__libc_alpha_cache_shape[1] = av->a_un.a_val;	\
+	break;						\
+      case AT_L2_CACHESHAPE:				\
+	__libc_alpha_cache_shape[2] = av->a_un.a_val;	\
+	break;						\
+      case AT_L3_CACHESHAPE:				\
+	__libc_alpha_cache_shape[3] = av->a_un.a_val;	\
+	break;
diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h
deleted file mode 100644
index b3d82f6..0000000
--- a/sysdeps/unix/sysv/linux/dl-parse_auxv.h
+++ /dev/null
@@ -1,61 +0,0 @@
-/* Parse the Linux auxiliary vector.
-   Copyright (C) 1995-2022 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <elf.h>
-#include <entry.h>
-#include <fpu_control.h>
-#include <ldsodefs.h>
-#include <link.h>
-
-typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];
-
-/* Copy the auxiliary vector into AUX_VALUES and set up GLRO
-   variables.  */
-static inline
-void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values)
-{
-  auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT;
-  auxv_values[AT_PAGESZ] = EXEC_PAGESIZE;
-  auxv_values[AT_FPUCW] = _FPU_DEFAULT;
-
-  /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
-  _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
-                  "CONSTANT_MINSIGSTKSZ is constant");
-  auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ;
-
-  for (; av->a_type != AT_NULL; av++)
-    if (av->a_type <= AT_MINSIGSTKSZ)
-      auxv_values[av->a_type] = av->a_un.a_val;
-
-  GLRO(dl_pagesize) = auxv_values[AT_PAGESZ];
-  __libc_enable_secure = auxv_values[AT_SECURE];
-  GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM];
-  GLRO(dl_hwcap) = auxv_values[AT_HWCAP];
-  GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2];
-  GLRO(dl_clktck) = auxv_values[AT_CLKTCK];
-  GLRO(dl_fpu_control) = auxv_values[AT_FPUCW];
-  _dl_random = (void *) auxv_values[AT_RANDOM];
-  GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ];
-  GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR];
-#ifdef NEED_DL_SYSINFO
-  if (GLRO(dl_sysinfo_dso) != NULL)
-    GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO];
-#endif
-
-  DL_PLATFORM_AUXV
-}
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
index 71cf196..5e71704 100644
--- a/sysdeps/unix/sysv/linux/dl-sysdep.c
+++ b/sysdeps/unix/sysv/linux/dl-sysdep.c
@@ -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
diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h
index ce2281c..5943719 100644
--- a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h
+++ b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h
@@ -16,5 +16,15 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#define DL_PLATFORM_AUXV \
-  GLRO(dl_cache_line_size) = auxv_values[AT_DCACHEBSIZE];
+#include <ldsodefs.h>
+
+#if IS_IN (libc) && !defined SHARED
+int GLRO(dl_cache_line_size);
+#endif
+
+/* Scan the Aux Vector for the "Data Cache Block Size" entry and assign it
+   to dl_cache_line_size.  */
+#define DL_PLATFORM_AUXV						      \
+      case AT_DCACHEBSIZE:						      \
+	GLRO(dl_cache_line_size) = av->a_un.a_val;			      \
+	break;
diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-support.c b/sysdeps/unix/sysv/linux/powerpc/dl-support.c
deleted file mode 100644
index abe68a7..0000000
--- a/sysdeps/unix/sysv/linux/powerpc/dl-support.c
+++ /dev/null
@@ -1,4 +0,0 @@
-#include <elf/dl-support.c>
-
-/* Populated from the auxiliary vector.  */
-int _dl_cache_line_size;