[PATCH v3 01/11] sframe: Ignore section padding when converting endianness

[Jens Remus]

The .sframe section may have a trailing padding due to the architecture-
specific default section alignment.  Do not treat this padding as error
when converting between target and host endianness.

This can be observed when building Binutils with SFrame s390x support on
x86-64 for s390x using configure option "--target=s390x-ibm-linux-gnu"
and running the GAS test suite.

While at it reuse the determined SFrame section header size.

libsframe/
	* sframe.c (flip_sframe): Ignore .sframe section padding.  Reuse
	SFrame header size.

Reported-by: Indu Bhagat <indu.bhagat@oracle.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---

Notes (jremus):
    Changes in V3:
    - Merge commit note into commit message. (Indu)

 libsframe/sframe.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index d38a61dbd636..3982157f70ce 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -498,7 +498,7 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
 	  fre_offset = fdep->sfde_func_start_fre_off;
 	}
 
-      fp = frame_buf + sframe_get_hdr_size (ihp) + ihp->sfh_freoff;
+      fp = frame_buf + hdrsz + ihp->sfh_freoff;
       fp += fre_offset;
       for (; j < prev_frep_index + num_fres; j++)
 	{
@@ -513,8 +513,12 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
       prev_frep_index = j;
     }
   /* All FDEs and FREs must have been endian flipped by now.  */
-  if ((j != ihp->sfh_num_fres) || (bytes_flipped != (buf_size - hdrsz)))
+  if ((j != ihp->sfh_num_fres) || (bytes_flipped > (buf_size - hdrsz)))
     goto bad;
+  /* Optional trailing section padding.  */
+  for (fp = frame_buf + hdrsz + bytes_flipped; fp < frame_buf + buf_size; fp++)
+    if (*fp != '\0')
+      goto bad;
 
   /* Success.  */
   return 0;
-- 
2.48.1