github.com/Aayushi-Bansal/sys@v0.0.0-20180118120756-90d962a959d8/unix/mkpost.go (about) 1 // Copyright 2016 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build ignore 6 7 // mkpost processes the output of cgo -godefs to 8 // modify the generated types. It is used to clean up 9 // the sys API in an architecture specific manner. 10 // 11 // mkpost is run after cgo -godefs; see README.md. 12 package main 13 14 import ( 15 "bytes" 16 "fmt" 17 "go/format" 18 "io/ioutil" 19 "log" 20 "os" 21 "regexp" 22 ) 23 24 func main() { 25 // Get the OS and architecture (using GOARCH_TARGET if it exists) 26 goos := os.Getenv("GOOS") 27 goarch := os.Getenv("GOARCH_TARGET") 28 if goarch == "" { 29 goarch = os.Getenv("GOARCH") 30 } 31 // Check that we are using the new build system if we should be. 32 if goos == "linux" && goarch != "sparc64" { 33 if os.Getenv("GOLANG_SYS_BUILD") != "docker" { 34 os.Stderr.WriteString("In the new build system, mkpost should not be called directly.\n") 35 os.Stderr.WriteString("See README.md\n") 36 os.Exit(1) 37 } 38 } 39 40 b, err := ioutil.ReadAll(os.Stdin) 41 if err != nil { 42 log.Fatal(err) 43 } 44 45 // If we have empty Ptrace structs, we should delete them. Only s390x emits 46 // nonempty Ptrace structs. 47 ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`) 48 b = ptraceRexexp.ReplaceAll(b, nil) 49 50 // Replace the control_regs union with a blank identifier for now. 51 controlRegsRegex := regexp.MustCompile(`(Control_regs)\s+\[0\]uint64`) 52 b = controlRegsRegex.ReplaceAll(b, []byte("_ [0]uint64")) 53 54 // Remove fields that are added by glibc 55 // Note that this is unstable as the identifers are private. 56 removeFieldsRegex := regexp.MustCompile(`X__glibc\S*`) 57 b = removeFieldsRegex.ReplaceAll(b, []byte("_")) 58 59 // Convert [65]int8 to [65]byte in Utsname members to simplify 60 // conversion to string; see golang.org/issue/20753 61 convertUtsnameRegex := regexp.MustCompile(`((Sys|Node|Domain)name|Release|Version|Machine)(\s+)\[(\d+)\]u?int8`) 62 b = convertUtsnameRegex.ReplaceAll(b, []byte("$1$3[$4]byte")) 63 64 // Remove spare fields (e.g. in Statx_t) 65 spareFieldsRegex := regexp.MustCompile(`X__spare\S*`) 66 b = spareFieldsRegex.ReplaceAll(b, []byte("_")) 67 68 // We refuse to export private fields on s390x 69 if goarch == "s390x" && goos == "linux" { 70 // Remove cgo padding fields 71 removeFieldsRegex := regexp.MustCompile(`Pad_cgo_\d+`) 72 b = removeFieldsRegex.ReplaceAll(b, []byte("_")) 73 74 // Remove padding, hidden, or unused fields 75 removeFieldsRegex = regexp.MustCompile(`\bX_\S+`) 76 b = removeFieldsRegex.ReplaceAll(b, []byte("_")) 77 } 78 79 // Remove the first line of warning from cgo 80 b = b[bytes.IndexByte(b, '\n')+1:] 81 // Modify the command in the header to include: 82 // mkpost, our own warning, and a build tag. 83 replacement := fmt.Sprintf(`$1 | go run mkpost.go 84 // Code generated by the command above; see README.md. DO NOT EDIT. 85 86 // +build %s,%s`, goarch, goos) 87 cgoCommandRegex := regexp.MustCompile(`(cgo -godefs .*)`) 88 b = cgoCommandRegex.ReplaceAll(b, []byte(replacement)) 89 90 // gofmt 91 b, err = format.Source(b) 92 if err != nil { 93 log.Fatal(err) 94 } 95 96 os.Stdout.Write(b) 97 }