# DP: Allow hwcap's to be disabled with the existence of a file. This
# DP: makes it easier to do upgrades with optimized (hwcap) library
# DP: packages.
# DP: Author: Rewritten by Daniel Jacobowitz <dan@debian.org>
# DP: Upstream status: Debian-Specific
# DP: Status Details: This isn't going to be acceptable upstream, we
# DP:                 only need it because we support in-place upgrades.
# DP: Date: 2003-10-28, (Updated 2005-01-02 gotom, 2007-05-20 aurel32)

---
 elf/dl-cache.c  |    8 ++++++++
 elf/dl-hwcaps.c |   26 +++++++++++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

--- a/elf/dl-hwcaps.c
+++ b/elf/dl-hwcaps.c
@@ -22,6 +22,9 @@
 #include <libintl.h>
 #include <unistd.h>
 #include <ldsodefs.h>
+#include <fcntl.h>
+#include <sysdep.h>
+#include <not-errno.h>

 #include <dl-procinfo.h>
 #include <dl-hwcaps.h>
@@ -43,6 +46,7 @@
   size_t cnt = platform != NULL;
   size_t n, m;
   size_t total;
+  struct r_strlenpair *temp;
   struct r_strlenpair *result;
   struct r_strlenpair *rp;
   char *cp;
@@ -124,8 +128,24 @@
   /* For TLS enabled builds always add 'tls'.  */
   ++cnt;
 
+#ifdef NEED_LD_SO_NOHWCAP
+  if (__access_noerrno ("/etc/ld.so.nohwcap", F_OK) == 0)
+    {
+      /* If hwcap is disabled, we only have the base directory to search.  */
+      result = (struct r_strlenpair *) malloc (sizeof (*result));
+      if (result == NULL)
+	goto no_memory;
+
+      result[0].str = (char *) result;  /* Does not really matter.  */
+      result[0].len = 0;
+
+      *sz = 1;
+      return result;
+    }
+#endif
+
   /* Create temporary data structure to generate result table.  */
-  struct r_strlenpair temp[cnt];
+  temp = (struct r_strlenpair *) alloca (cnt * sizeof (*temp));
   m = 0;
 #ifdef NEED_DL_SYSINFO_DSO
   if (dsocaps != NULL)
@@ -210,8 +230,13 @@
   *sz = 1 << cnt;
   result = (struct r_strlenpair *) malloc (*sz * sizeof (*result) + total);
   if (result == NULL)
-    _dl_signal_error (ENOMEM, NULL, NULL,
-		      N_("cannot create capability list"));
+    {
+#ifdef NEED_LD_SO_NOHWCAP
+    no_memory:
+#endif
+      _dl_signal_error (ENOMEM, NULL, NULL,
+		     	N_("cannot create capability list"));
+    }
 
   if (cnt == 1)
     {
--- a/elf/dl-cache.c
+++ b/elf/dl-cache.c
@@ -25,6 +25,9 @@
 #include <stdint.h>
 #include <_itoa.h>
 #include <dl-hwcaps.h>
+#include <fcntl.h>
+#include <sysdep.h>
+#include <not-errno.h>
 
 #ifndef _DL_PLATFORMS_COUNT
 # define _DL_PLATFORMS_COUNT 0
@@ -246,6 +249,7 @@
   if (cache_new != (void *) -1)
     {
       uint64_t platform;
+      int disable_hwcap = 0;
 
       /* This is where the strings start.  */
       cache_data = (const char *) cache_new;
@@ -259,6 +263,11 @@
 
       uint64_t hwcap_mask = GET_HWCAP_MASK();
 
+#ifdef NEED_LD_SO_NOHWCAP
+      if (__access_noerrno ("/etc/ld.so.nohwcap", F_OK) == 0)
+	disable_hwcap = 1;
+#endif
+
 #define _DL_HWCAP_TLS_MASK (1LL << 63)
       uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & hwcap_mask)
 				 | _DL_HWCAP_PLATFORM | _DL_HWCAP_TLS_MASK);
@@ -269,6 +278,8 @@
 	continue;							      \
       if (GLRO(dl_osversion) && lib->osversion > GLRO(dl_osversion))	      \
 	continue;							      \
+      if (disable_hwcap && lib->hwcap != 0)				      \
+	continue;							      \
       if (_DL_PLATFORMS_COUNT						      \
 	  && (lib->hwcap & _DL_HWCAP_PLATFORM) != 0			      \
 	  && (lib->hwcap & _DL_HWCAP_PLATFORM) != platform)		      \
--- a/sysdeps/alpha/ldsodefs.h
+++ b/sysdeps/alpha/ldsodefs.h
@@ -37,6 +37,8 @@ struct La_alpha_retval;
 				      struct La_alpha_retval *,		\
 				      const char *);

+#define NEED_LD_SO_NOHWCAP
+
 #include_next <ldsodefs.h>

 #endif
--- a/sysdeps/i386/ldsodefs.h
+++ b/sysdeps/i386/ldsodefs.h
@@ -0,0 +1,7 @@
+#ifndef __LDSODEFS_H
+
+#define NEED_LD_SO_NOHWCAP
+
+#include_next <ldsodefs.h>
+
+#endif