* elf/elf.h: Define AT_EXECFN.

* elf/rtld.c [!__ASSUME_AT_EXECFN] (process_envvars): Don't handle
	LD_ORIGIN_PATH.
	* elf/dl-sysdep.c (_dl_sysdep_start): Handle AT_EXECFN.
	* elf/dl-support.c: Define _dl_execfn.  Don't define _dl_origin_path
	if __ASSUME_AT_EXECFN is defined.
	(_dl_aux_init): Handle AT_EXECFN.
	* sysdeps/unix/sysv/linux/kernel-features.h: Define __ASSUME_AT_EXECFN
	for 2.6.27 and up.
	* sysdeps/generic/ldsodefs.h (rtld_global_ro): Add _dl_execfn.
	Don't define _dl_origin_path if __ASSUME_AT_EXECFN is defined.
	* sysdeps/unix/sysv/linux/dl-origin.c (_dl_get_origin): Use
	_dl_execfn if available and avoid compatibility code if
	__ASSUME_AT_EXECFN is defined.

ChangeLog

@@ -1,5 +1,20 @@
 2008-07-24  Ulrich Drepper  <drepper@redhat.com>
 
+	* elf/elf.h: Define AT_EXECFN.
+	* elf/rtld.c [!__ASSUME_AT_EXECFN] (process_envvars): Don't handle
+	LD_ORIGIN_PATH.
+	* elf/dl-sysdep.c (_dl_sysdep_start): Handle AT_EXECFN.
+	* elf/dl-support.c: Define _dl_execfn.  Don't define _dl_origin_path
+	if __ASSUME_AT_EXECFN is defined.
+	(_dl_aux_init): Handle AT_EXECFN.
+	* sysdeps/unix/sysv/linux/kernel-features.h: Define __ASSUME_AT_EXECFN
+	for 2.6.27 and up.
+	* sysdeps/generic/ldsodefs.h (rtld_global_ro): Add _dl_execfn.
+	Don't define _dl_origin_path if __ASSUME_AT_EXECFN is defined.
+	* sysdeps/unix/sysv/linux/dl-origin.c (_dl_get_origin): Use
+	_dl_execfn if available and avoid compatibility code if
+	__ASSUME_AT_EXECFN is defined.
+
 	* sysdeps/unix/sysv/linux/dl-sysdep.h: Don't declare
 	_dl_discover_osversion only for older kernels.
 

elf/dl-support.c

@@ -1,5 +1,5 @@
 /* Support for dynamic linking code in static libc.
-   Copyright (C) 1996-2005, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1996-2005, 2006, 2007, 2008 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
@@ -62,8 +62,12 @@ struct link_map *_dl_profile_map;
 /* This is the address of the last stack address ever used.  */
 void *__libc_stack_end;
 
+#ifndef __ASSUME_AT_EXECFN
 /* Path where the binary is found.  */
 const char *_dl_origin_path;
+#endif
+/* File Name of the executable.  */
+const char *_dl_execfn;
 
 /* Nonzero if runtime lookup should not update the .got/.plt.  */
 int _dl_bind_not;
@@ -216,6 +220,9 @@ _dl_aux_init (ElfW(auxv_t) *av)
 	__libc_enable_secure = av->a_un.a_val;
 	__libc_enable_secure_decided = 1;
 	break;
+      case AT_EXECFN:
+	GLRO(dl_execfn) = (void *) av->a_un.a_val;
+	break;
 # ifdef DL_PLATFORM_AUXV
       DL_PLATFORM_AUXV
 # endif

elf/dl-sysdep.c

@@ -173,6 +173,9 @@ _dl_sysdep_start (void **start_argptr,
 	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
 	break;
 #endif
+      case AT_EXECFN:
+	GLRO(dl_execfn) = (void *) av->a_un.a_val;
+	break;
 #ifdef DL_PLATFORM_AUXV
       DL_PLATFORM_AUXV
 #endif

elf/elf.h

@@ -970,6 +970,8 @@ typedef struct
 
 #define	AT_SECURE	23		/* Boolean, was exec setuid-like?  */
 
+#define AT_EXECFN	31		/* Filename of executable.  */
+
 /* Pointer to the global system page used for system calls and other
    nice things.  */
 #define AT_SYSINFO	32

elf/rtld.c

@@ -2579,10 +2579,12 @@ process_envvars (enum mode *modep)
 	  break;
 
 	case 11:
+#ifndef __ASSUME_AT_EXECFN
 	  /* Path where the binary is found.  */
 	  if (!INTUSE(__libc_enable_secure)
 	      && memcmp (envline, "ORIGIN_PATH", 11) == 0)
 	    GLRO(dl_origin_path) = &envline[12];
+#endif
 	  break;
 
 	case 12:

sysdeps/generic/ldsodefs.h

@@ -38,6 +38,7 @@
 #include <bits/libc-lock.h>
 #include <hp-timing.h>
 #include <tls.h>
+#include <kernel-features.h>
 
 __BEGIN_DECLS
 
@@ -592,8 +593,13 @@ struct rtld_global_ro
   /* Names of shared object for which the RPATH should be ignored.  */
   EXTERN const char *_dl_inhibit_rpath;
 
+#ifndef __ASSUME_AT_EXECFN
   /* Location of the binary.  */
   EXTERN const char *_dl_origin_path;
+#endif
+
+  /* If set, points to the file name of the executable.  */
+  EXTERN const char *_dl_execfn;
 
   /* -1 if the dynamic linker should honor library load bias,
      0 if not, -2 use the default (honor biases for normal

sysdeps/unix/sysv/linux/dl-origin.c

@@ -1,5 +1,5 @@
 /* Find path of executable.
-   Copyright (C) 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1998-2000, 2002, 2004, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
 
@@ -35,30 +35,32 @@
 const char *
 _dl_get_origin (void)
 {
+#ifndef __ASSUME_AT_EXECFN
   char linkval[PATH_MAX];
-  char *result;
+#endif
+  char *str;
+  char *result = (char *) -1l;
   int len;
-  INTERNAL_SYSCALL_DECL (err);
 
-  len = INTERNAL_SYSCALL (readlink, err, 3, "/proc/self/exe", linkval,
+  str = GLRO(dl_execfn);
-			  sizeof (linkval));
+#ifndef __ASSUME_AT_EXECFN
-  if (! INTERNAL_SYSCALL_ERROR_P (len, err) && len > 0 && linkval[0] != '[')
+  if (str == NULL)
     {
-      /* We can use this value.  */
+      INTERNAL_SYSCALL_DECL (err);
-      assert (linkval[0] == '/');
+
-      while (len > 1 && linkval[len - 1] != '/')
+      len = INTERNAL_SYSCALL (readlink, err, 3, "/proc/self/exe", linkval,
-	--len;
+			      sizeof (linkval));
-      result = (char *) malloc (len + 1);
+      if (! INTERNAL_SYSCALL_ERROR_P (len, err)
-      if (result == NULL)
+	  && len > 0 && linkval[0] != '[')
-	result = (char *) -1;
+	str = linkval;
-      else if (len == 1)
-	memcpy (result, "/", 2);
-      else
-	*((char *) __mempcpy (result, linkval, len - 1)) = '\0';
     }
   else
+#endif
+    len = strlen (str);
+
+#ifndef __ASSUME_AT_EXECFN
+  if (str == NULL)
     {
-      result = (char *) -1;
       /* We use the environment variable LD_ORIGIN_PATH.  If it is set make
 	 a copy and strip out trailing slashes.  */
       if (GLRO(dl_origin_path) != NULL)
@@ -76,6 +78,21 @@ _dl_get_origin (void)
 	    }
 	}
     }
+  else
+#endif
+    {
+      /* We can use this value.  */
+      assert (str[0] == '/');
+      while (len > 1 && str[len - 1] != '/')
+	--len;
+      result = (char *) malloc (len + 1);
+      if (result == NULL)
+	result = (char *) -1;
+      else if (len == 1)
+	memcpy (result, "/", 2);
+      else
+	*((char *) __mempcpy (result, str, len - 1)) = '\0';
+    }
 
   return result;
 }

sysdeps/unix/sysv/linux/kernel-features.h

@@ -1,6 +1,6 @@
 /* Set flags signalling availability of kernel features based on given
    kernel version number.
-   Copyright (C) 1999-2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1999-2006, 2007, 2008 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
@@ -492,3 +492,8 @@
 #if __LINUX_KERNEL_VERSION >= 0x020618
 # define __ASSUME_ADJ_OFFSET_SS_READ	1
 #endif
+
+/* Support for AT_EXECFN was added in 2.6.27.  */
+#if __LINUX_KERNEL_VERSION >= 0x02061b
+# define __ASSUME_AT_EXECFN	1
+#endif