Teach readelf about some OpenBSD ELF program headers

- Add constants for OpenBSD wxneeded, bootdata and randomize to the
  FreeBSD elf_common.h file. This is the file that gets used by the
  elftoolchain library.
- Update readelf and elfdump utilities to decode these program headers
  if they are encountered.

Note: FreeBSD has it's own version of elfdump(1), which will be updated
in a subsequent commit. I am adding it here anyway because this diff is
going to be submitted upstream.

Discussed with:	emaste
Reviewed by:	imp
MFC afer:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D20548

M    contrib/elftoolchain/elfdump/elfdump.c
M    contrib/elftoolchain/readelf/readelf.c
M    sys/sys/elf_common.h

Author: csjayp

contrib/elftoolchain/elfdump/elfdump.c

@@ -343,17 +343,20 @@ elf_phdr_type_str(unsigned int type)
 	static char s_type[32];
 
 	switch (type) {
-	case PT_NULL:		return "PT_NULL";
-	case PT_LOAD:		return "PT_LOAD";
-	case PT_DYNAMIC:	return "PT_DYNAMIC";
-	case PT_INTERP:		return "PT_INTERP";
-	case PT_NOTE:		return "PT_NOTE";
-	case PT_SHLIB:		return "PT_SHLIB";
-	case PT_PHDR:		return "PT_PHDR";
-	case PT_TLS:		return "PT_TLS";
-	case PT_GNU_EH_FRAME:	return "PT_GNU_EH_FRAME";
-	case PT_GNU_STACK:	return "PT_GNU_STACK";
-	case PT_GNU_RELRO:	return "PT_GNU_RELRO";
+	case PT_NULL:			return "PT_NULL";
+	case PT_LOAD:			return "PT_LOAD";
+	case PT_DYNAMIC:		return "PT_DYNAMIC";
+	case PT_INTERP:			return "PT_INTERP";
+	case PT_NOTE:			return "PT_NOTE";
+	case PT_SHLIB:			return "PT_SHLIB";
+	case PT_PHDR:			return "PT_PHDR";
+	case PT_TLS:			return "PT_TLS";
+	case PT_GNU_EH_FRAME:		return "PT_GNU_EH_FRAME";
+	case PT_GNU_STACK:		return "PT_GNU_STACK";
+	case PT_GNU_RELRO:		return "PT_GNU_RELRO";
+	case PT_OPENBSD_RANDOMIZE:	return "PT_OPENBSD_RANDOMIZE";
+	case PT_OPENBSD_WXNEEDED:	return "PT_OPENBSD_WXNEEDED";
+	case PT_OPENBSD_BOOTDATA:	return "PT_OPENBSD_BOOTDATA";
 	}
 	snprintf(s_type, sizeof(s_type), "<unknown: %#x>", type);
 	return (s_type);

contrib/elftoolchain/readelf/readelf.c

@@ -674,6 +674,9 @@ phdr_type(unsigned int mach, unsigned int ptype)
 	case PT_GNU_EH_FRAME: return "GNU_EH_FRAME";
 	case PT_GNU_STACK: return "GNU_STACK";
 	case PT_GNU_RELRO: return "GNU_RELRO";
+	case PT_OPENBSD_RANDOMIZE: return "OPENBSD_RANDOMIZE";
+	case PT_OPENBSD_WXNEEDED: return "OPENBSD_WXNEEDED";
+	case PT_OPENBSD_BOOTDATA: return "OPENBSD_BOOTDATA";
 	default:
 		if (ptype >= PT_LOOS && ptype <= PT_HIOS)
 			snprintf(s_ptype, sizeof(s_ptype), "LOOS+%#x",

sys/sys/elf_common.h

@@ -535,6 +535,10 @@ typedef struct {
 #define	PT_ARM_EXIDX	0x70000001	/* ARM exception unwind tables. */
 #define	PT_HIPROC	0x7fffffff	/* Last processor-specific type. */
 
+#define	PT_OPENBSD_RANDOMIZE	0x65A3DBE6	/* OpenBSD random data segment */
+#define	PT_OPENBSD_WXNEEDED	0x65A3DBE7	/* OpenBSD EXEC/WRITE pages needed */
+#define	PT_OPENBSD_BOOTDATA	0x65A41BE6	/* OpenBSD section for boot args */
+
 /* Values for p_flags. */
 #define	PF_X		0x1		/* Executable. */
 #define	PF_W		0x2		/* Writable. */