From 0d0fbbe73f5b02bfeac0aedd0b6b9e8417ab0b0f Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Fri, 26 Aug 2016 07:09:25 +0200
Subject: overhaul syscall description generation process

This splits generation process into two phases:
1. Extract values of constants from linux kernel sources.
2. Generate Go code.

Constant values are checked in.
The advantage is that the second phase is now completely independent
from linux source files, kernel version, presence of headers for
particular drivers, etc. This allows to change what Go code we generate
any time without access to all kernel headers (which in future won't be
limited to only upstream headers).

Constant extraction process does require proper kernel sources,
but this can be done only once by the person who added the driver
and has access to the required sources. Then the constant values
are checked in for others to use.
Consant extraction process is per-file/per-arch. That is,
if I am adding a driver that is not present upstream and that
works only on a single arch, I will check in constants only for
that driver and for that arch.
---
 sysparser/parser.go | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 sysparser/parser.go

(limited to 'sysparser/parser.go')

diff --git a/sysparser/parser.go b/sysparser/parser.go
new file mode 100644
index 000000000..590847b0e
--- /dev/null
+++ b/sysparser/parser.go
@@ -0,0 +1,101 @@
+// Copyright 2015/2016 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package sysparser
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+)
+
+type parser struct {
+	r *bufio.Scanner
+	s string
+	i int
+	l int
+}
+
+func newParser(r io.Reader) *parser {
+	return &parser{r: bufio.NewScanner(r)}
+}
+
+func (p *parser) Scan() bool {
+	if !p.r.Scan() {
+		if err := p.r.Err(); err != nil {
+			failf("failed to read input file: %v", err)
+		}
+		return false
+	}
+	p.s = p.r.Text()
+	p.i = 0
+	p.l++
+	return true
+}
+
+func (p *parser) Str() string {
+	return p.s
+}
+
+func (p *parser) EOF() bool {
+	return p.i == len(p.s)
+}
+
+func (p *parser) Char() byte {
+	if p.EOF() {
+		p.failf("unexpected eof")
+	}
+	return p.s[p.i]
+}
+
+func (p *parser) Parse(ch byte) {
+	if p.EOF() {
+		p.failf("want %s, got EOF", string(ch))
+	}
+	if p.s[p.i] != ch {
+		p.failf("want '%v', got '%v'", string(ch), string(p.s[p.i]))
+	}
+	p.i++
+	p.SkipWs()
+}
+
+func (p *parser) SkipWs() {
+	for p.i < len(p.s) && (p.s[p.i] == ' ' || p.s[p.i] == '\t') {
+		p.i++
+	}
+}
+
+func (p *parser) Ident() string {
+	start, end := p.i, 0
+	if p.Char() == '"' {
+		p.Parse('"')
+		start++
+		for p.Char() != '"' {
+			p.i++
+		}
+		end = p.i
+		p.Parse('"')
+	} else {
+		for p.i < len(p.s) &&
+			(p.s[p.i] >= 'a' && p.s[p.i] <= 'z' ||
+				p.s[p.i] >= 'A' && p.s[p.i] <= 'Z' ||
+				p.s[p.i] >= '0' && p.s[p.i] <= '9' ||
+				p.s[p.i] == '_' || p.s[p.i] == '$' || // $ is for n-way syscalls (like ptrace$peek)
+				p.s[p.i] == '-' || p.s[p.i] == ':') { // : is for ranged int (like int32[-3:10])
+			p.i++
+		}
+		if start == p.i {
+			p.failf("failed to parse identifier at pos %v", start)
+		}
+		end = p.i
+	}
+	s := p.s[start:end]
+	p.SkipWs()
+	return s
+}
+
+func (p *parser) failf(msg string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "line #%v: %v\n", p.l, p.s)
+	failf(msg, args...)
+}
-- 
cgit mrf-deployment