ld/6l/8l: First pass at changes to the linker to support NetBSD binaries.

This will not currently create valid NetBSD binaries because NetBSD requires
an ELF note section to run, otherwise the kernel will throw ENOEXEC. I was
unable to determine an elegant way to add the section, so I am submitting
what I have.

References:
http://www.netbsd.org/docs/kernel/elf-notes.html
http://mail-index.netbsd.org/netbsd-bugs/2001/08/03/0012.html

R=rsc
CC=golang-dev
https://golang.org/cl/5472049

src/cmd/6l/asm.c

@@ -44,6 +44,7 @@
 char linuxdynld[] = "/lib64/ld-linux-x86-64.so.2";
 char freebsddynld[] = "/libexec/ld-elf.so.1";
 char openbsddynld[] = "/usr/libexec/ld.so";
+char netbsddynld[] = "/libexec/ld.elf_so";
 
 char	zeroes[32];
 
@@ -95,6 +96,7 @@ enum {
 	ElfStrPlt,
 	ElfStrGnuVersion,
 	ElfStrGnuVersionR,
+	ElfStrNoteNetbsdIdent,
 	NElfStr
 };
 
@@ -558,7 +560,7 @@ doelf(void)
 {
 	Sym *s, *shstrtab, *dynstr;
 
-	if(HEADTYPE != Hlinux && HEADTYPE != Hfreebsd && HEADTYPE != Hopenbsd)
+	if(HEADTYPE != Hlinux && HEADTYPE != Hfreebsd && HEADTYPE != Hopenbsd && HEADTYPE != Hnetbsd)
 		return;
 
 	/* predefine strings we need for section headers */
@@ -570,6 +572,8 @@ doelf(void)
 	elfstr[ElfStrText] = addstring(shstrtab, ".text");
 	elfstr[ElfStrData] = addstring(shstrtab, ".data");
 	elfstr[ElfStrBss] = addstring(shstrtab, ".bss");
+	if(HEADTYPE == Hnetbsd)
+		elfstr[ElfStrNoteNetbsdIdent] = addstring(shstrtab, ".note.netbsd.ident");
 	addstring(shstrtab, ".elfdata");
 	addstring(shstrtab, ".rodata");
 	addstring(shstrtab, ".gosymtab");
@@ -763,6 +767,7 @@ asmb(void)
 		break;
 	case Hlinux:
 	case Hfreebsd:
+	case Hnetbsd:
 	case Hopenbsd:
 		debug['8'] = 1;	/* 64-bit addresses */
 		/* index of elf text section; needed by asmelfsym, double-checked below */
@@ -798,6 +803,7 @@ asmb(void)
 			break;
 		case Hlinux:
 		case Hfreebsd:
+		case Hnetbsd:
 		case Hopenbsd:
 			symo = rnd(HEADR+segtext.len, INITRND)+segdata.filelen;
 			symo = rnd(symo, INITRND);
@@ -867,6 +873,7 @@ asmb(void)
 		break;
 	case Hlinux:
 	case Hfreebsd:
+	case Hnetbsd:
 	case Hopenbsd:
 		/* elf amd-64 */
 
@@ -910,6 +917,9 @@ asmb(void)
 				case Hfreebsd:
 					interpreter = freebsddynld;
 					break;
+				case Hnetbsd:
+					interpreter = netbsddynld;
+					break;
 				case Hopenbsd:
 					interpreter = openbsddynld;
 					break;
@@ -1076,6 +1086,8 @@ asmb(void)
 		eh->ident[EI_MAG3] = 'F';
 		if(HEADTYPE == Hfreebsd)
 			eh->ident[EI_OSABI] = ELFOSABI_FREEBSD;
+		else if(HEADTYPE == Hnetbsd)
+			eh->ident[EI_OSABI] = ELFOSABI_NETBSD;
 		else if(HEADTYPE == Hopenbsd)
 			eh->ident[EI_OSABI] = ELFOSABI_OPENBSD;
 		eh->ident[EI_CLASS] = ELFCLASS64;

src/cmd/6l/doc.go

@@ -31,6 +31,8 @@ Options new in this version:
 	Write Linux ELF binaries (default when $GOOS is linux)
 -Hfreebsd
 	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
+-Hnetbsd
+	Write NetBSD ELF binaries (default when $GOOS is netbsd)
 -Hopenbsd
 	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
 -Hwindows

src/cmd/6l/obj.c

@@ -50,6 +50,7 @@ Header headers[] = {
 	"darwin", Hdarwin,
 	"linux", Hlinux,
 	"freebsd", Hfreebsd,
+	"netbsd", Hnetbsd,
 	"openbsd", Hopenbsd,
 	"windows", Hwindows,
 	"windowsgui", Hwindows,
@@ -63,6 +64,7 @@ Header headers[] = {
  *	-Hdarwin -Tx -Rx		is apple MH-exec
  *	-Hlinux -Tx -Rx			is linux elf-exec
  *	-Hfreebsd -Tx -Rx		is FreeBSD elf-exec
+ *	-Hnetbsd -Tx -Rx		is NetBSD elf-exec
  *	-Hopenbsd -Tx -Rx		is OpenBSD elf-exec
  *	-Hwindows -Tx -Rx		is MS Windows PE32+
  *
@@ -197,6 +199,7 @@ main(int argc, char *argv[])
 		break;
 	case Hlinux:	/* elf64 executable */
 	case Hfreebsd:	/* freebsd */
+	case Hnetbsd:	/* netbsd */
 	case Hopenbsd:	/* openbsd */
 		/*
 		 * ELF uses TLS offset negative from FS.

src/cmd/6l/pass.c

@@ -295,7 +295,7 @@ patch(void)
 			}
 		}
 		if(HEADTYPE == Hlinux || HEADTYPE == Hfreebsd
-		|| HEADTYPE == Hopenbsd) {
+		|| HEADTYPE == Hopenbsd || HEADTYPE == Hnetbsd) {
 			// ELF uses FS instead of GS.
 			if(p->from.type == D_INDIR+D_GS)
 				p->from.type = D_INDIR+D_FS;
@@ -421,7 +421,7 @@ dostkoff(void)
 			p = appendp(p);	// load g into CX
 			p->as = AMOVQ;
 			if(HEADTYPE == Hlinux || HEADTYPE == Hfreebsd
-			|| HEADTYPE == Hopenbsd)	// ELF uses FS
+			|| HEADTYPE == Hopenbsd || HEADTYPE == Hnetbsd)	// ELF uses FS
 				p->from.type = D_INDIR+D_FS;
 			else
 				p->from.type = D_INDIR+D_GS;

src/cmd/8l/asm.c

@@ -42,6 +42,7 @@
 char linuxdynld[] = "/lib/ld-linux.so.2";
 char freebsddynld[] = "/usr/libexec/ld-elf.so.1";
 char openbsddynld[] = "/usr/libexec/ld.so";
+char netbsddynld[] = "/usr/libexec/ld.elf_so";
 
 int32
 entryvalue(void)
@@ -969,6 +970,9 @@ asmb(void)
 				case Hfreebsd:
 					interpreter = freebsddynld;
 					break;
+				case Hnetbsd:
+					interpreter = netbsddynld;
+					break;
 				case Hopenbsd:
 					interpreter = openbsddynld;
 					break;
@@ -1140,6 +1144,9 @@ asmb(void)
 		case Hfreebsd:
 			eh->ident[EI_OSABI] = ELFOSABI_FREEBSD;
 			break;
+		case Hnetbsd:
+			eh->ident[EI_OSABI] = ELFOSABI_NETBSD;
+			break;
 		case Hopenbsd:
 			eh->ident[EI_OSABI] = ELFOSABI_OPENBSD;
 			break;

src/cmd/8l/doc.go

@@ -33,6 +33,8 @@ Options new in this version:
 	Write Linux ELF binaries (default when $GOOS is linux)
 -Hfreebsd
 	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
+-Hnetbsd
+	Write NetBSD ELF binaries (default when $GOOS is netbsd)
 -Hopenbsd
 	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
 -Hwindows

src/cmd/8l/obj.c

@@ -55,6 +55,7 @@ Header headers[] = {
 	"darwin", Hdarwin,
 	"linux", Hlinux,
 	"freebsd", Hfreebsd,
+	"netbsd", Hnetbsd,
 	"openbsd", Hopenbsd,
 	"windows", Hwindows,
 	"windowsgui", Hwindows,
@@ -70,6 +71,7 @@ Header headers[] = {
  *	-Hdarwin -Tx -Rx			is Apple Mach-O
  *	-Hlinux -Tx -Rx				is Linux ELF32
  *	-Hfreebsd -Tx -Rx			is FreeBSD ELF32
+ *	-Hnetbsd -Tx -Rx			is NetBSD ELF32
  *	-Hopenbsd -Tx -Rx			is OpenBSD ELF32
  *	-Hwindows -Tx -Rx			is MS Windows PE32
  */
@@ -225,6 +227,7 @@ main(int argc, char *argv[])
 		break;
 	case Hlinux:	/* elf32 executable */
 	case Hfreebsd:
+	case Hnetbsd:
 	case Hopenbsd:
 		/*
 		 * ELF uses TLS offsets negative from %gs.

src/cmd/cc/godefs.c

@@ -124,11 +124,11 @@ Uconv(Fmt *fp)
 
 	if(s && *s) {
 		if(upper)
-			str[0] = toupper(*s);
+			str[0] = toupper((uchar)*s);
 		else
-			str[0] = tolower(*s);
+			str[0] = tolower((uchar)*s);
 		for(i = 1; i < STRINGSZ && s[i] != 0; i++)
-			str[i] = tolower(s[i]);
+			str[i] = tolower((uchar)s[i]);
 		str[i] = 0;
 	}
 

src/cmd/ld/lib.c

@@ -115,7 +115,7 @@ addlib(char *src, char *obj)
 		sprint(name, "");
 		i = 1;
 	} else
-	if(isalpha(histfrog[0]->name[1]) && histfrog[0]->name[2] == ':') {
+	if(isalpha((uchar)histfrog[0]->name[1]) && histfrog[0]->name[2] == ':') {
 		strcpy(name, histfrog[0]->name+1);
 		i = 1;
 	} else