blob: e1712cbe0a6516180dd582cf33d083ba591a7117 [file] [log] [blame]
// 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.
//go:build ignore
// +build ignore
package main
import (
"bufio"
"fmt"
"os"
"os/exec"
"regexp"
"sort"
"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:], " ")
}
// goBuildTags returns build tags in the go:build format.
func goBuildTags() string {
return fmt.Sprintf("%s && %s", goarch, goos)
}
// plusBuildTags returns build tags in the +build format.
func plusBuildTags() string {
return fmt.Sprintf("%s,%s", goarch, goos)
}
func format(name string, num int, offset int) (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 0, ""
}
name = strings.ToUpper(name)
num = num + offset
return num, 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
}
// syscallNum holds the syscall number and the string
// we will write to the generated file.
type syscallNum struct {
num int
declaration string
}
// syscallNums is a slice of syscallNum sorted by the syscall number in ascending order.
type syscallNums []syscallNum
// addSyscallNum adds the syscall declaration to syscallNums.
func (nums *syscallNums) addSyscallNum(num int, declaration string) {
if declaration == "" {
return
}
if len(*nums) == 0 || (*nums)[len(*nums)-1].num <= num {
// This is the most common case as the syscall declarations output by the preprocessor
// are almost always sorted.
*nums = append(*nums, syscallNum{num, declaration})
return
}
i := sort.Search(len(*nums), func(i int) bool { return (*nums)[i].num >= num })
// Maintain the ordering in the preprocessor output when we have multiple definitions with
// the same value. i cannot be > len(nums) - 1 as nums[len(nums)-1].num > num.
for ; (*nums)[i].num == num; i++ {
}
*nums = append((*nums)[:i], append([]syscallNum{{num, declaration}}, (*nums)[i:]...)...)
}
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)
}
s := bufio.NewScanner(strings.NewReader(string(cmd)))
var offset, prev, asOffset int
var nums syscallNums
for s.Scan() {
t := re{str: s.Text()}
// The generated zsysnum_linux_*.go files for some platforms (arm64, loong64, riscv64)
// treat SYS_ARCH_SPECIFIC_SYSCALL as if it's a syscall which it isn't. It's an offset.
// However, as this constant is already part of the public API we leave it in place.
// Lines of type SYS_ARCH_SPECIFIC_SYSCALL = 244 are thus processed twice, once to extract
// the offset and once to add the constant.
if t.Match(`^#define __NR_arch_specific_syscall\s+([0-9]+)`) {
// riscv: extract arch specific offset
asOffset, _ = strconv.Atoi(t.sub[1]) // Make asOffset=0 if empty or non-numeric
}
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)
nums.addSyscallNum(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)
nums.addSyscallNum(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)
nums.addSyscallNum(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)
nums.addSyscallNum(format(t.sub[1], r2, offset))
} else if asOffset != 0 && t.Match(`^#define __NR_(\w+)\s+\(__NR_arch_specific_syscall \+ ([0-9]+)`) {
r2, err := strconv.Atoi(t.sub[2])
checkErr(err)
nums.addSyscallNum(format(t.sub[1], r2, asOffset))
}
}
err = s.Err()
checkErr(err)
var text strings.Builder
for _, num := range nums {
text.WriteString(num.declaration)
}
fmt.Printf(template, cmdLine(), goBuildTags(), plusBuildTags(), text.String())
}
const template = `// %s
// Code generated by the command above; see README.md. DO NOT EDIT.
//go:build %s
// +build %s
package unix
const(
%s)`