[binutils-gdb/binutils-2_26-branch] Allow zero length archive elements

[Alan Modra <amodra at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=343a405c03ce478634d8ce5a38faae832d39b361

commit 343a405c03ce478634d8ce5a38faae832d39b361
Author: Alan Modra <amodra@gmail.com>
Date:   Wed Mar 9 17:01:54 2016 +1030

    Allow zero length archive elements
    
    bfd/
    	PR binutils/19775
    	* archive.c (bfd_generic_openr_next_archived_file): Allow zero
    	length elements in the archive.
    	* coff-alpha.c (alpha_ecoff_openr_next_archived_file): Likewise.
    
    binutils/
    	PR binutils/19775
    	* testsuite/binutils-all/ar.exp (proc empty_archive): New proc.
    	Run the new proc.
    	* testsuite/binutils-all/empty: New, empty, file.

Diff:
---
 bfd/ChangeLog                          |  8 +++++++
 bfd/archive.c                          |  2 +-
 bfd/coff-alpha.c                       |  2 +-
 binutils/ChangeLog                     |  7 ++++++
 binutils/testsuite/binutils-all/ar.exp | 40 ++++++++++++++++++++++++++++++++++
 binutils/testsuite/binutils-all/empty  |  0
 6 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ce32d43..0a08b55 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,11 @@
+2016-03-09  Nick Clifton  <nickc@redhat.com>
+	    Alan Modra  <amodra@gmail.com>
+
+	PR binutils/19775
+	* archive.c (bfd_generic_openr_next_archived_file): Allow zero
+	length elements in the archive.
+	* coff-alpha.c (alpha_ecoff_openr_next_archived_file): Likewise.
+
 2016-03-01  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/19752
diff --git a/bfd/archive.c b/bfd/archive.c
index b3d03d3..1fc3a94 100644
--- a/bfd/archive.c
+++ b/bfd/archive.c
@@ -802,7 +802,7 @@ bfd_generic_openr_next_archived_file (bfd *archive, bfd *last_file)
 	     Note that last_file->origin can be odd in the case of
 	     BSD-4.4-style element with a long odd size.  */
 	  filestart += filestart % 2;
-	  if (filestart <= last_file->proxy_origin)
+	  if (filestart < last_file->proxy_origin)
 	    {
 	      /* Prevent looping.  See PR19256.  */
 	      bfd_set_error (bfd_error_malformed_archive);
diff --git a/bfd/coff-alpha.c b/bfd/coff-alpha.c
index 7478f2f..fffb9f7 100644
--- a/bfd/coff-alpha.c
+++ b/bfd/coff-alpha.c
@@ -2208,7 +2208,7 @@ alpha_ecoff_openr_next_archived_file (bfd *archive, bfd *last_file)
 	 BSD-4.4-style element with a long odd size.  */
       filestart = last_file->proxy_origin + size;
       filestart += filestart % 2;
-      if (filestart <= last_file->proxy_origin)
+      if (filestart < last_file->proxy_origin)
 	{
 	  /* Prevent looping.  See PR19256.  */
 	  bfd_set_error (bfd_error_malformed_archive);
diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 4648d93..b04c745 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,10 @@
+2016-03-09  Nick Clifton  <nickc@redhat.com>
+
+	PR binutils/19775
+	* testsuite/binutils-all/ar.exp (proc empty_archive): New proc.
+	Run the new proc.
+	* testsuite/binutils-all/empty: New, empty, file.
+
 2016-02-12  H.J. Lu  <hongjiu.lu@intel.com>
 
 	Backport from master
diff --git a/binutils/testsuite/binutils-all/ar.exp b/binutils/testsuite/binutils-all/ar.exp
index 4c33874..e971350 100644
--- a/binutils/testsuite/binutils-all/ar.exp
+++ b/binutils/testsuite/binutils-all/ar.exp
@@ -555,6 +555,45 @@ proc move_an_element { } {
     pass $testname
 }
 
+# PR 19775: Test creating and listing archives with an empty element.
+
+proc empty_archive { } {
+    global AR
+    global srcdir
+    global subdir
+
+    set testname "archive with empty element"
+
+    # FIXME: There ought to be a way to dynamically create an empty file.
+    set empty $srcdir/$subdir/empty
+    
+    if [is_remote host] {
+	set archive artest.a
+	set objfile [remote_download host $empty]
+	remote_file host delete $archive
+    } else {
+	set archive tmpdir/artest.a
+	set objfile $empty
+    }
+
+    remote_file build delete tmpdir/artest.a
+
+    set got [binutils_run $AR "-r -c $archive ${objfile}"]
+    if ![string match "" $got] {
+	fail $testname
+	return
+    }
+
+    # This commmand used to fail with: "Malformed archive".
+    set got [binutils_run $AR "-t $archive"]
+    if ![string match "empty
" $got] {
+	fail $testname
+	return
+    }
+
+    pass $testname
+}
+
 # Run the tests.
 
 # Only run the bfdtest checks if the programs exist.  Since these
@@ -574,6 +613,7 @@ argument_parsing
 deterministic_archive
 delete_an_element
 move_an_element
+empty_archive
 
 if { [is_elf_format]
      && ![istarget "*-*-hpux*"]
diff --git a/binutils/testsuite/binutils-all/empty b/binutils/testsuite/binutils-all/empty
new file mode 100644
index 0000000..e69de29