[PATCH 2/2] [nto] Improve ABI sniffing.

[Aleksandar Ristovski <aristovski at qnx dot com>]

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 | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index e50d302..48826cb 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 +335,51 @@ 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;
+  char *note; // buffer holding the section contents
+  unsigned int namelen;
+  const char *name;
+
+  sectname = bfd_get_section_name (abfd, sect);
+  sectsize = bfd_section_size (abfd, sect);
+
+  /* TODO: limit the note size here, for now limit is 128 bytes
+     (enough to check the name and type).  */
+  if (sectsize > 128)
+    sectsize = 128;
+
+  if (sectname && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
+    *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+  if (sectname && strstr (sectname, "note") != NULL)
+    {
+      note = alloca (sectsize);
+      bfd_get_section_contents (abfd, sect, note, 0, sectsize);
+      namelen = (unsigned int) bfd_h_get_32 (abfd, note);
+      name = note + 12;
+
+      if (namelen > 0
+	  && (0 == strcmp (name, QNX_NOTE_NAME)))
+        *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+    }
+}
+
 enum gdb_osabi
 nto_elf_osabi_sniffer (bfd *abfd)
 {
-  if (nto_is_nto_target)
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+
+  bfd_map_over_sections (abfd,
+			 nto_sniff_abi_note_section,
+			 &osabi);
+
+  if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
     return nto_is_nto_target (abfd);
-  return GDB_OSABI_UNKNOWN;
+  return osabi;
 }
 
 static const char *nto_thread_state_str[] =
-- 
1.9.1