Rename obj_mac.h to nid.h and make it a multiply-includable header.

obj_mac.h is missing #include guards, so one cannot use NIDs without
pulling in the OBJ_* functions which depend on the giant OID table. Give
it #include guards, tidy up the style slightly, and also rename it to
nid.h which is a much more reasonable name.

obj_mac.h is kept as a forwarding header as, despite it being a little
screwy, some code #includes it anyway.

BUG=chromium:499653

Change-Id: Iec0b3f186c02e208ff1f7437bf27ee3a5ad004b7
Reviewed-on: https://boringssl-review.googlesource.com/7562
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>

crypto/obj/README

@@ -1,17 +1,17 @@
 OID information is generated via a series of perl scripts. In order, the full
 list of commands to run are:
 
-        perl objects.pl objects.txt obj_mac.num ../../include/openssl/obj_mac.h
-        perl obj_dat.pl ../../include/openssl/obj_mac.h obj_dat.h
+        perl objects.pl objects.txt obj_mac.num ../../include/openssl/nid.h
+        perl obj_dat.pl ../../include/openssl/nid.h obj_dat.h
         perl obj_xref.pl obj_mac.num obj_xref.txt > obj_xref.h
 
 objects.txt contains the list of all built-in OIDs. It is processed by
-objects.pl to output obj_mac.num and obj_mac.h. obj_mac.num is the list of NID
+objects.pl to output obj_mac.num and nid.h. obj_mac.num is the list of NID
 values for each OID. This is an input/output parameter so NID values are stable
-across regenerations. obj_mac.h is the header which defines macros for all the
+across regenerations. nid.h is the header which defines macros for all the
 built-in OIDs in C.
 
-obj_mac.h is read by obj_dat.pl to generate obj_dat.h. obj_dat.h contains the
+nid.h is read by obj_dat.pl to generate obj_dat.h. obj_dat.h contains the
 ASN1_OBJECTs corresponding to built-in OIDs themselves along with lookup tables
 for search by short name, OID, etc.
 
@@ -28,7 +28,7 @@ Dependency graph:
                        [objects.pl] <--+
                          /      \      |
                         V        V     |
-                  obj_mac.h    obj_mac.num  obj_xref.txt
+                     nid.h     obj_mac.num  obj_xref.txt
                       |              \      /
                       V               V    V
                  [obj_dat.pl]      [obj_xref.pl]

crypto/obj/obj_dat.h

@@ -1,6 +1,6 @@
 /* THIS FILE IS GENERATED FROM objects.h by obj_dat.pl via the
  * following command:
- * perl obj_dat.pl ../../include/openssl/obj_mac.h obj_dat.h */
+ * perl obj_dat.pl ../../include/openssl/nid.h obj_dat.h */
 
 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
  * All rights reserved.

crypto/obj/obj_dat.pl

@@ -6,7 +6,7 @@ use integer;
 
 if (scalar @ARGV != 2)
 	{
-	print "Usage: perl obj_dat.pl ../../include/openssl/obj_mac.h obj_dat.h\n";
+	print "Usage: perl obj_dat.pl ../../include/openssl/nid.h obj_dat.h\n";
 	exit 1;
 	}
 
@@ -176,7 +176,7 @@ foreach (sort obj_cmp @a)
 print OUT <<'EOF';
 /* THIS FILE IS GENERATED FROM objects.h by obj_dat.pl via the
  * following command:
- * perl obj_dat.pl ../../include/openssl/obj_mac.h obj_dat.h */
+ * perl obj_dat.pl ../../include/openssl/nid.h obj_dat.h */
 
 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
  * All rights reserved.

crypto/obj/objects.pl

@@ -2,7 +2,7 @@
 
 if (scalar @ARGV != 3)
 	{
-	print "Usage: perl objects.pl objects.txt obj_mac.num ../../include/openssl/obj_mac.h\n";
+	print "Usage: perl objects.pl objects.txt obj_mac.num ../../include/openssl/nid.h\n";
 	exit 1;
 	}
 
@@ -127,7 +127,7 @@ open (OUT,">$ARGV[2]") || die "Can't open output file $ARGV[2]";
 print OUT <<'EOF';
 /* THIS FILE IS GENERATED FROM objects.txt by objects.pl via the
  * following command:
- * perl objects.pl objects.txt obj_mac.num ../../include/openssl/obj_mac.h */
+ * perl objects.pl objects.txt obj_mac.num ../../include/openssl/nid.h */
 
 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
@@ -186,23 +186,43 @@ print OUT <<'EOF';
  * [including the GNU Public Licence.]
  */
 
-#define SN_undef			"UNDEF"
-#define LN_undef			"undefined"
-#define NID_undef			0
-#define OBJ_undef			0L
+#ifndef OPENSSL_HEADER_NID_H
+#define OPENSSL_HEADER_NID_H
+
+
+/* The nid library provides numbered values for ASN.1 object identifiers and
+ * other symbols. These values are used by other libraries to identify
+ * cryptographic primitives.
+ *
+ * A separate objects library, obj.h, provides functions for converting between
+ * nids and object identifiers. However it depends on large internal tables with
+ * the encodings of every nid defind. Consumers concerned with binary size
+ * should instead embed the encodings of the few consumed OIDs and compare
+ * against those.
+ *
+ * These values should not be used outside of a single process; they are not
+ * stable identifiers. */
+
+
+#define SN_undef "UNDEF"
+#define LN_undef "undefined"
+#define NID_undef 0
+#define OBJ_undef 0L
 
 EOF
 
 foreach (sort { $a <=> $b } keys %ordern)
 	{
 	$Cname=$ordern{$_};
-	print OUT "#define SN_",$Cname,"\t\t\"",$sn{$Cname},"\"\n" if $sn{$Cname} ne "";
-	print OUT "#define LN_",$Cname,"\t\t\"",$ln{$Cname},"\"\n" if $ln{$Cname} ne "";
-	print OUT "#define NID_",$Cname,"\t\t",$nid{$Cname},"\n" if $nid{$Cname} ne "";
-	print OUT "#define OBJ_",$Cname,"\t\t",$obj{$Cname},"\n" if $obj{$Cname} ne "";
+	print OUT "#define SN_",$Cname," \"",$sn{$Cname},"\"\n" if $sn{$Cname} ne "";
+	print OUT "#define LN_",$Cname," \"",$ln{$Cname},"\"\n" if $ln{$Cname} ne "";
+	print OUT "#define NID_",$Cname," ",$nid{$Cname},"\n" if $nid{$Cname} ne "";
+	print OUT "#define OBJ_",$Cname," ",$obj{$Cname},"\n" if $obj{$Cname} ne "";
 	print OUT "\n";
 	}
 
+print OUT "\n#endif  /* OPENSSL_HEADER_NID_H */\n";
+
 close OUT;
 
 sub process_oid

include/openssl/obj.h

@@ -60,7 +60,7 @@
 #include <openssl/base.h>
 
 #include <openssl/bytestring.h>
-#include <openssl/obj_mac.h>
+#include <openssl/nid.h>
 
 #if defined(__cplusplus)
 extern "C" {