prog: allow arbitrary long lines in serialized programs

We use bufio.Scanner and it has mandatory limit on line length.
The file system tests (sys/linux/test/syz_mount_image_*) has
very long lines (megabytes).
Remove the restriction on line length.

1 files changed, 23 insertions, 21 deletions

diff --git a/prog/encoding.go b/prog/encoding.go
index 77c2356b8..140636865 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -4,7 +4,6 @@
 package prog
 
 import (
-	"bufio"
 	"bytes"
 	"encoding/hex"
 	"fmt"
@@ -721,7 +720,6 @@ func (p *parser) eatExcessive(stopAtComma bool, what string, args ...interface{}
 
 const (
 	encodingAddrBase = 0x7f0000000000
-	maxLineLen       = 1 << 20
 )
 
 func (target *Target) serializeAddr(arg *PointerArg) string {
@@ -979,11 +977,11 @@ type parser struct {
 	autos   map[Arg]bool
 	comment string
 
-	r *bufio.Scanner
-	s string
-	i int
-	l int
-	e error
+	data []byte
+	s    string
+	i    int
+	l    int
+	e    error
 }
 
 func newParser(target *Target, data []byte, strict bool) *parser {
@@ -991,9 +989,8 @@ func newParser(target *Target, data []byte, strict bool) *parser {
 		target: target,
 		strict: strict,
 		vars:   make(map[string]*ResultArg),
-		r:      bufio.NewScanner(bytes.NewReader(data)),
+		data:   data,
 	}
-	p.r.Buffer(nil, maxLineLen)
 	return p
 }
 
@@ -1032,14 +1029,17 @@ func (p *parser) fixupAutos(prog *Prog) {
 }
 
 func (p *parser) Scan() bool {
-	if p.e != nil {
+	if p.e != nil || len(p.data) == 0 {
 		return false
 	}
-	if !p.r.Scan() {
-		p.e = p.r.Err()
-		return false
+	nextLine := bytes.IndexByte(p.data, '\n')
+	if nextLine != -1 {
+		p.s = string(p.data[:nextLine])
+		p.data = p.data[nextLine+1:]
+	} else {
+		p.s = string(p.data)
+		p.data = nil
 	}
-	p.s = p.r.Text()
 	p.i = 0
 	p.l++
 	return true
@@ -1138,10 +1138,15 @@ func (p *parser) strictFailf(msg string, args ...interface{}) {
 func CallSet(data []byte) (map[string]struct{}, int, error) {
 	calls := make(map[string]struct{})
 	ncalls := 0
-	s := bufio.NewScanner(bytes.NewReader(data))
-	s.Buffer(nil, maxLineLen)
-	for s.Scan() {
-		ln := s.Bytes()
+	for len(data) > 0 {
+		ln := data
+		nextLine := bytes.IndexByte(data, '\n')
+		if nextLine != -1 {
+			ln = data[:nextLine]
+			data = data[nextLine+1:]
+		} else {
+			data = nil
+		}
 		if len(ln) == 0 || ln[0] == '#' {
 			continue
 		}
@@ -1163,9 +1168,6 @@ func CallSet(data []byte) (map[string]struct{}, int, error) {
 		calls[string(call)] = struct{}{}
 		ncalls++
 	}
-	if err := s.Err(); err != nil {
-		return nil, 0, err
-	}
 	if len(calls) == 0 {
 		return nil, 0, fmt.Errorf("program does not contain any calls")
 	}