syscall: make sure go error numbers do not clash with windows system errors

R=rsc
CC=golang-dev
https://golang.org/cl/1857049

src/pkg/syscall/mkall.sh

@@ -154,7 +154,7 @@ windows_386)
 	mksyscall="./mksyscall_windows.sh -l32"
 	mksysnum=
 	mktypes=
-	mkerrors=
+	mkerrors="./mkerrors_windows.sh -f -m32"
 	;;
 *)
 	echo 'unrecognized $GOOS_$GOARCH: ' "$GOOSARCH" 1>&2

src/pkg/syscall/mkerrors_windows.sh

+#!/usr/bin/env bash
+# Copyright 2009 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# Generate Go code listing errors and other #defined constant
+# values (ENAMETOOLONG etc.), by asking the preprocessor
+# about the definitions.
+
+unset LANG
+export LC_ALL=C
+export LC_CTYPE=C
+
+case "$GOARCH" in
+arm)
+	GCC=arm-gcc
+	;;
+*)
+	GCC=gcc
+	;;
+esac
+
+uname=$(uname)
+
+includes_Linux='
+#define _LARGEFILE_SOURCE
+#define _LARGEFILE64_SOURCE
+#define _FILE_OFFSET_BITS 64
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+#include <sys/epoll.h>
+#include <linux/ptrace.h>
+#include <linux/wait.h>
+'
+
+includes_Darwin='
+#define __DARWIN_UNIX03 0
+#define KERNEL
+#define _DARWIN_USE_64_BIT_INODE
+#include <sys/wait.h>
+#include <sys/event.h>
+'
+
+includes_FreeBSD='
+#include <sys/wait.h>
+#include <sys/event.h>
+'
+
+includes='
+#include <sys/types.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <errno.h>
+#include <sys/signal.h>
+#include <signal.h>
+'
+
+ccflags=""
+next=false
+for i
+do
+	if $next; then
+		ccflags="$ccflags $i"
+		next=false
+	elif [ "$i" = "-f" ]; then
+		next=true
+	fi
+done
+
+# Pull out just the error names for later.
+errors=$(
+	echo '#include <errno.h>' | $GCC -x c - -E -dM $ccflags |
+	awk '
+		$1 != "#define" || $2 ~ /\(/ {next}
+		$2 ~ /^ENOTDIR$/ {next}
+		$2 ~ /^E[A-Z0-9_]+$/ { print $2 }
+		{next}
+	' | sort
+)
+
+echo '// mkerrors_windows.sh' "$@"
+echo '// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT'
+echo
+echo 'package syscall'
+
+# Run C program to print error strings.
+(
+	/bin/echo "
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <string.h>
+
+#define nelem(x) (sizeof(x)/sizeof((x)[0]))
+
+enum { A = 'A', Z = 'Z', a = 'a', z = 'z' }; // avoid need for single quotes below
+
+struct {
+	char *name;
+	int value;
+} errors[] = {
+"
+	for i in $errors
+	do
+		/bin/echo '	{"'$i'",' $i'},'
+	done
+
+	# Use /bin/echo to avoid builtin echo,
+	# which interprets \n itself
+	/bin/echo '
+};
+
+int
+main(void)
+{
+	int i, j, e, iota = 1;
+	char buf[1024];
+
+	printf("\nconst (\n");
+	for(i=0; i<nelem(errors); i++) {
+		e = errors[i].value;
+		strcpy(buf, strerror(e));
+		// lowercase first letter: Bad -> bad, but STREAM -> STREAM.
+		if(A <= buf[0] && buf[0] <= Z && a <= buf[1] && buf[1] <= z)
+			buf[0] += a - A;
+		printf("\t%s", errors[i].name);
+		if(iota) {
+			printf(" = APPLICATION_ERROR + iota");
+			iota = !iota;
+		}
+		printf("\n");
+			
+	}
+	printf("\tEWINDOWS\n");
+	printf(")\n");
+
+	printf("\n// Error table\n");
+	printf("var errors = [...]string {\n");
+	for(i=0; i<nelem(errors); i++) {
+		e = errors[i].value;
+		for(j=0; j<i; j++)
+			if(errors[j].value == e)	// duplicate value
+				goto next;
+		strcpy(buf, strerror(e));
+		// lowercase first letter: Bad -> bad, but STREAM -> STREAM.
+		if(A <= buf[0] && buf[0] <= Z && a <= buf[1] && buf[1] <= z)
+			buf[0] += a - A;
+		printf("\t%s - APPLICATION_ERROR: \"%s\",\n", errors[i].name, buf);
+	next:;
+	}
+	printf("\tEWINDOWS - APPLICATION_ERROR: \"not supported by windows\",\n");
+	printf("}\n\n");
+	return 0;
+}
+
+'
+) >_errors.c
+
+$GCC $ccflags -static -o _errors _errors.c && $GORUN ./_errors && rm -f _errors.c _errors

src/pkg/syscall/mksyscall_windows.sh

@@ -216,8 +216,10 @@ while(<>) {
 			$ret[$i] = sprintf("r%d", $i);
 			$ret[$i+1] = sprintf("r%d", $i+1);
 		}
+		my $rettype = $type;
 		if($type =~ /^\*/) {
 			$reg = "unsafe.Pointer($reg)";
+			$rettype = "($rettype)";
 		}
 		if($i == 0) {
 			if($type eq "bool") {
@@ -241,7 +243,7 @@ while(<>) {
 			$body .= "\t\t$name = 0;\n";
 			$body .= "\t}\n";
 		} else {
-			$body .= "\t$name = ($type)($reg);\n";
+			$body .= "\t$name = $rettype($reg);\n";
 		}
 		push @pout, sprintf "\"%s=\", %s, ", $name, $name;
 	}

src/pkg/syscall/syscall_windows.go

@@ -147,9 +147,12 @@ func getSysProcAddr(m uint32, pname string) uintptr {
 // syscall interface implementation for other packages
 
 func Errstr(errno int) string {
-	if errno == EWINDOWS {
-		return "not supported by windows"
+	// deal with special go errors
+	e := errno - APPLICATION_ERROR
+	if 0 <= e && e < len(errors) {
+		return errors[e]
 	}
+	// ask windows for the remaining errors
 	var flags uint32 = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ARGUMENT_ARRAY | FORMAT_MESSAGE_IGNORE_INSERTS
 	b := make([]uint16, 300)
 	n, err := FormatMessage(flags, 0, uint32(errno), 0, b, nil)

src/pkg/syscall/zsyscall_windows_386.go

@@ -887,13 +887,13 @@ func GetServByName(name string, proto string) (s *Servent, errno int) {
 
 func Ntohs(netshort uint16) (u uint16) {
 	r0, _, _ := Syscall(procntohs, uintptr(netshort), 0, 0)
-	u = (uint16)(r0)
+	u = uint16(r0)
 	return
 }
 
 func DnsQuery(name string, qtype uint16, options uint32, extra *byte, qrs **DNSRecord, pr *byte) (status uint32) {
 	r0, _, _ := Syscall6(procDnsQuery_W, uintptr(unsafe.Pointer(StringToUTF16Ptr(name))), uintptr(qtype), uintptr(options), uintptr(unsafe.Pointer(extra)), uintptr(unsafe.Pointer(qrs)), uintptr(unsafe.Pointer(pr)))
-	status = (uint32)(r0)
+	status = uint32(r0)
 	return
 }
 

src/pkg/syscall/ztypes_windows_386.go

@@ -17,6 +17,22 @@ const (
 	SizeofCmsghdr  = 0xc
 )
 
+const (
+	// Windows errors.
+	ERROR_FILE_NOT_FOUND      = 2
+	ERROR_NO_MORE_FILES       = 18
+	ERROR_BROKEN_PIPE         = 109
+	ERROR_INSUFFICIENT_BUFFER = 122
+	ERROR_MOD_NOT_FOUND       = 126
+	ERROR_PROC_NOT_FOUND      = 127
+	ERROR_DIRECTORY           = 267
+	ERROR_IO_PENDING          = 997
+	// Go names for Windows errors.
+	ENOTDIR = ERROR_DIRECTORY
+	// Windows reserves errors >= 1<<29 for application use.
+	APPLICATION_ERROR = 1 << 29
+)
+
 const (
 	// Invented values to support what package os expects.
 	O_RDONLY   = 0x00000