From 6df97e71696e47d85000413bf4a97cf5d43b11f1 Mon Sep 17 00:00:00 2001
From: Aleksandar Ristovski <aristovski@qnx.com>
Date: Wed, 21 Oct 2015 09:29:54 -0400
Subject: [PATCH 2/2] [nto] Improve ABI sniffing.

Use qnx specific notes to figure out the OS.

gdb/ChangeLog:
	* gdb/nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
	(nto_sniff_abi_note_section): New function.
	(nto_elf_osabi_sniffer): Use new function to recognize nto specific
	binary.
---
 gdb/nto-tdep.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index e50d302..4e0cc84 100644
--- a/gdb/nto-tdep.c
+++ b/gdb/nto-tdep.c
@@ -32,6 +32,9 @@
 #include "gdbcore.h"
 #include "objfiles.h"
 
+#define QNX_NOTE_NAME	"QNX"
+#define QNX_INFO_SECT_NAME "QNX_info"
+
 #ifdef __CYGWIN__
 #include <sys/cygwin.h>
 #endif
@@ -332,12 +335,58 @@ nto_dummy_supply_regset (struct regcache *regcache, char *regs)
   /* Do nothing.  */
 }
 
+static void
+nto_sniff_abi_note_section (bfd *abfd, asection *sect, void *obj)
+{
+  const char *sectname;
+  unsigned int sectsize;
+  /* Buffer holding the section contents.  */
+  char *note;
+  unsigned int namelen;
+  const char *name;
+
+  sectname = bfd_get_section_name (abfd, sect);
+  sectsize = bfd_section_size (abfd, sect);
+
+  if (sectsize > 128)
+    sectsize = 128;
+
+  if (sectname != NULL && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
+    *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+  if (sectname != NULL && strstr (sectname, "note") != NULL)
+    {
+      const unsigned sizeof_Elf_Nhdr = 12;
+
+      note = XNEWVEC (char, sectsize);
+      bfd_get_section_contents (abfd, sect, note, 0, sectsize);
+      namelen = (unsigned int) bfd_h_get_32 (abfd, note);
+      name = note + sizeof_Elf_Nhdr;
+      if (sectsize < namelen + sizeof_Elf_Nhdr
+	  || namelen > sizeof (QNX_NOTE_NAME) + 1)
+	{
+	  /* Can not be QNX note.  */
+	  XDELETEVEC (note);
+	  return;
+	}
+
+      if (namelen > 0 && 0 == strcmp (name, QNX_NOTE_NAME))
+        *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+      XDELETEVEC (note);
+    }
+}
+
 enum gdb_osabi
 nto_elf_osabi_sniffer (bfd *abfd)
 {
-  if (nto_is_nto_target)
-    return nto_is_nto_target (abfd);
-  return GDB_OSABI_UNKNOWN;
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+
+  bfd_map_over_sections (abfd,
+			 nto_sniff_abi_note_section,
+			 &osabi);
+
+  return osabi;
 }
 
 static const char *nto_thread_state_str[] =
-- 
1.9.1