1 files changed, 67 insertions, 0 deletions
diff --git a/cmd/hsu/parse.go b/cmd/hsu/parse.go
new file mode 100644
index 00000000..35704c61
--- /dev/null
+++ b/cmd/hsu/parse.go
@@ -0,0 +1,67 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"strings"
+)
+
+func parseUint32Fast(s string) (int, error) {
+	sLen := len(s)
+	if sLen < 1 {
+		return -1, errors.New("zero length string")
+	}
+	if sLen > 10 {
+		return -1, errors.New("string too long")
+	}
+
+	n := 0
+	for i, ch := range []byte(s) {
+		ch -= '0'
+		if ch > 9 {
+			return -1, fmt.Errorf("invalid character '%s' at index %d", string(ch+'0'), i)
+		}
+		n = n*10 + int(ch)
+	}
+	return n, nil
+}
+
+func parseConfig(r io.Reader, puid int) (fid int, ok bool, err error) {
+	s := bufio.NewScanner(r)
+	var line, puid0 int
+	for s.Scan() {
+		line++
+
+		// <puid> <fid>
+		lf := strings.SplitN(s.Text(), " ", 2)
+		if len(lf) != 2 {
+			return -1, false, fmt.Errorf("invalid entry on line %d", line)
+		}
+
+		puid0, err = parseUint32Fast(lf[0])
+		if err != nil || puid0 < 1 {
+			return -1, false, fmt.Errorf("invalid parent uid on line %d", line)
+		}
+
+		ok = puid0 == puid
+		if ok {
+			// allowed fid range 0 to 99
+			if fid, err = parseUint32Fast(lf[1]); err != nil || fid < 0 || fid > 99 {
+				return -1, false, fmt.Errorf("invalid identity on line %d", line)
+			}
+			return
+		}
+	}
+	return -1, false, s.Err()
+}
+
+func mustParseConfig(r io.Reader, puid int) (int, bool) {
+	fid, ok, err := parseConfig(r, puid)
+	if err != nil {
+		log.Fatal(err)
+	}
+	return fid, ok
+}