From 73fc4e28b9464f0e13edc719a5372839970e7ddb Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 28 Feb 2022 11:50:41 +0100
Subject: Linux: Consolidate auxiliary vector parsing (redo)

And optimize it slightly.

This is commit 8c8510ab2790039e58995ef3a22309582413d3ff revised.

In _dl_aux_init in elf/dl-support.c, use an explicit loop
and -fno-tree-loop-distribute-patterns to avoid memset.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
---
 elf/Makefile     |  5 ++++
 elf/dl-support.c | 85 ++++++--------------------------------------------------
 2 files changed, 14 insertions(+), 76 deletions(-)

(limited to 'elf')

diff --git a/elf/Makefile b/elf/Makefile
index 281551d..c96924e 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -160,6 +160,11 @@ ifeq (yes,$(have-loop-to-function))
 CFLAGS-rtld.c += -fno-tree-loop-distribute-patterns
 endif
 
+ifeq (yes,$(have-loop-to-function))
+# Likewise, during static library startup, memset is not yet available.
+CFLAGS-dl-support.c = -fno-tree-loop-distribute-patterns
+endif
+
 # Compile rtld itself without stack protection.
 # Also compile all routines in the static library that are elided from
 # the shared libc because they are in libc.a in the same way.
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 6d2c4ba..153dd57 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -44,6 +44,7 @@
 #include <dl-vdso-setup.h>
 #include <dl-auxv.h>
 #include <dl-find_object.h>
+#include <array_length.h>
 
 extern char *__progname;
 char **_dl_argv = &__progname;	/* This is checked for some error messages.  */
@@ -240,93 +241,25 @@ __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;
-  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;
-    }
+  dl_parse_auxv_t auxv_values;
+  /* Use an explicit initialization loop here because memset may not
+     be available yet.  */
+  for (int i = 0; i < array_length (auxv_values); ++i)
+    auxv_values[i] = 0;
+  _dl_parse_auxv (av, auxv_values);
 }
 #endif
 
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