make syscall use strings for file names

tweak os to adjust
move StringToBytes into syscall, at least for now

this program still works:

	package main

	import os "os"

	func main() {
		os.Stdout.WriteString("hello, world\n");
		a, b := os.NewFD(77).WriteString("no way");
		os.Stdout.WriteString(b.String() + "\n");
	}

R=rsc
DELTA=263  (59 added, 176 deleted, 28 changed)
OCL=15153
CL=15153

1 files changed, 14 insertions, 0 deletions

diff --git a/src/syscall/syscall.go b/src/syscall/syscall.go
index 7f31c11c9..384be2429 100644
--- a/src/syscall/syscall.go
+++ b/src/syscall/syscall.go
@@ -11,3 +11,17 @@ package syscall
 export func Syscall(trap int64, a1, a2, a3 int64) (r1, r2, err int64);
 export func AddrToInt(b *byte) int64;
 
+/*
+ * Used to convert file names to byte arrays for passing to kernel,
+ * but useful elsewhere too.
+ */
+export func StringToBytes(b *[]byte, s string) bool {
+	if len(s) >= len(b) {
+		return false
+	}
+	for i := 0; i < len(s); i++ {
+		b[i] = s[i]
+	}
+	b[len(s)] = '\000';	// not necessary - memory is zeroed - but be explicit
+	return true
+}