unix/linux: replace "mksysnum.pl" script with a Go program
Port mksysnum.pl Perl script to mksysnum.go.
mkall scripts are modified to run mksysnum.go.
Running ./mkall.sh does not generate any git diff besides
the command name in comments of generated files.
Updates golang/go#27779
Change-Id: Id62df9d819f00729ab19b6bc4d32dddcf8d9832b
Reviewed-on: https://go-review.googlesource.com/c/151377
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
diff --git a/unix/linux/mksysnum.go b/unix/linux/mksysnum.go
new file mode 100755
index 0000000..e1ad597
--- /dev/null
+++ b/unix/linux/mksysnum.go
@@ -0,0 +1,143 @@
+// Copyright 2018 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.
+
+// +build ignore
+
+package main
+
+import (
+ "bufio"
+ "fmt"
+ "os"
+ "os/exec"
+ "regexp"
+ "strconv"
+ "strings"
+)
+
+var (
+ goos, goarch string
+)
+
+// cmdLine returns this programs's commandline arguments
+func cmdLine() string {
+ return "go run linux/mksysnum.go " + strings.Join(os.Args[1:], " ")
+}
+
+// buildTags returns build tags
+func buildTags() string {
+ return fmt.Sprintf("%s,%s", goarch, goos)
+}
+
+func format(name string, num int, offset int) string {
+ if num > 999 {
+ // ignore deprecated syscalls that are no longer implemented
+ // https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/uapi/asm-generic/unistd.h?id=refs/heads/master#n716
+ return ""
+ }
+ name = strings.ToUpper(name)
+ num = num + offset
+ return fmt.Sprintf(" SYS_%s = %d;\n", name, num)
+}
+
+func checkErr(err error) {
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "%v\n", err)
+ os.Exit(1)
+ }
+}
+
+// source string and substring slice for regexp
+type re struct {
+ str string // source string
+ sub []string // matched sub-string
+}
+
+// Match performs regular expression match
+func (r *re) Match(exp string) bool {
+ r.sub = regexp.MustCompile(exp).FindStringSubmatch(r.str)
+ if r.sub != nil {
+ return true
+ }
+ return false
+}
+
+func main() {
+ // Get the OS and architecture (using GOARCH_TARGET if it exists)
+ goos = os.Getenv("GOOS")
+ goarch = os.Getenv("GOARCH_TARGET")
+ if goarch == "" {
+ goarch = os.Getenv("GOARCH")
+ }
+ // Check if GOOS and GOARCH environment variables are defined
+ if goarch == "" || goos == "" {
+ fmt.Fprintf(os.Stderr, "GOARCH or GOOS not defined in environment\n")
+ os.Exit(1)
+ }
+ // Check that we are using the new build system if we should
+ if os.Getenv("GOLANG_SYS_BUILD") != "docker" {
+ fmt.Fprintf(os.Stderr, "In the new build system, mksysnum should not be called directly.\n")
+ fmt.Fprintf(os.Stderr, "See README.md\n")
+ os.Exit(1)
+ }
+
+ cc := os.Getenv("CC")
+ if cc == "" {
+ fmt.Fprintf(os.Stderr, "CC is not defined in environment\n")
+ os.Exit(1)
+ }
+ args := os.Args[1:]
+ args = append([]string{"-E", "-dD"}, args...)
+ cmd, err := exec.Command(cc, args...).Output() // execute command and capture output
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "can't run %s", cc)
+ os.Exit(1)
+ }
+ text := ""
+ s := bufio.NewScanner(strings.NewReader(string(cmd)))
+ var offset, prev int
+ for s.Scan() {
+ t := re{str: s.Text()}
+ if t.Match(`^#define __NR_Linux\s+([0-9]+)`) {
+ // mips/mips64: extract offset
+ offset, _ = strconv.Atoi(t.sub[1]) // Make offset=0 if empty or non-numeric
+ } else if t.Match(`^#define __NR(\w*)_SYSCALL_BASE\s+([0-9]+)`) {
+ // arm: extract offset
+ offset, _ = strconv.Atoi(t.sub[1]) // Make offset=0 if empty or non-numeric
+ } else if t.Match(`^#define __NR_syscalls\s+`) {
+ // ignore redefinitions of __NR_syscalls
+ } else if t.Match(`^#define __NR_(\w*)Linux_syscalls\s+`) {
+ // mips/mips64: ignore definitions about the number of syscalls
+ } else if t.Match(`^#define __NR_(\w+)\s+([0-9]+)`) {
+ prev, err = strconv.Atoi(t.sub[2])
+ checkErr(err)
+ text += format(t.sub[1], prev, offset)
+ } else if t.Match(`^#define __NR3264_(\w+)\s+([0-9]+)`) {
+ prev, err = strconv.Atoi(t.sub[2])
+ checkErr(err)
+ text += format(t.sub[1], prev, offset)
+ } else if t.Match(`^#define __NR_(\w+)\s+\(\w+\+\s*([0-9]+)\)`) {
+ r2, err := strconv.Atoi(t.sub[2])
+ checkErr(err)
+ text += format(t.sub[1], prev+r2, offset)
+ } else if t.Match(`^#define __NR_(\w+)\s+\(__NR_(?:SYSCALL_BASE|Linux) \+ ([0-9]+)`) {
+ r2, err := strconv.Atoi(t.sub[2])
+ checkErr(err)
+ text += format(t.sub[1], r2, offset)
+ }
+ }
+ err = s.Err()
+ checkErr(err)
+ fmt.Printf(template, cmdLine(), buildTags(), text)
+}
+
+const template = `// %s
+// Code generated by the command above; see README.md. DO NOT EDIT.
+
+// +build %s
+
+package unix
+
+const(
+%s)`
