From owner-svn-src-all@FreeBSD.ORG  Tue Oct  6 17:14:39 2009
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id C9BE31065672;
	Tue,  6 Oct 2009 17:14:39 +0000 (UTC)
	(envelope-from rwatson@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id B90FA8FC12;
	Tue,  6 Oct 2009 17:14:39 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id n96HEdOP053185;
	Tue, 6 Oct 2009 17:14:39 GMT (envelope-from rwatson@svn.freebsd.org)
Received: (from rwatson@localhost)
	by svn.freebsd.org (8.14.3/8.14.3/Submit) id n96HEd4U053183;
	Tue, 6 Oct 2009 17:14:39 GMT (envelope-from rwatson@svn.freebsd.org)
Message-Id: <200910061714.n96HEd4U053183@svn.freebsd.org>
From: Robert Watson <rwatson@FreeBSD.org>
Date: Tue, 6 Oct 2009 17:14:39 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-head@freebsd.org
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r197808 - head/libexec/rtld-elf
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
	user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Oct 2009 17:14:39 -0000

Author: rwatson
Date: Tue Oct  6 17:14:39 2009
New Revision: 197808
URL: http://svn.freebsd.org/changeset/base/197808

Log:
  In rtld's map_object(), use pread(..., 0) rather than read() to read the
  ELF header from the front of the file.  As all other I/O on the binary
  is done using mmap(), this avoids the need for seek privileges on the
  file descriptor during run-time linking.
  
  MFC after:	1 month
  Sponsored by:	Google

Modified:
  head/libexec/rtld-elf/map_object.c

Modified: head/libexec/rtld-elf/map_object.c
==============================================================================
--- head/libexec/rtld-elf/map_object.c	Tue Oct  6 17:10:38 2009	(r197807)
+++ head/libexec/rtld-elf/map_object.c	Tue Oct  6 17:14:39 2009	(r197808)
@@ -273,7 +273,7 @@ get_elf_header (int fd, const char *path
     } u;
     ssize_t nbytes;
 
-    if ((nbytes = read(fd, u.buf, PAGE_SIZE)) == -1) {
+    if ((nbytes = pread(fd, u.buf, PAGE_SIZE, 0)) == -1) {
 	_rtld_error("%s: read error: %s", path, strerror(errno));
 	return NULL;
     }