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.
12package main
13
14import (
15	"bytes"
16	"fmt"
17	"go/format"
18	"io/ioutil"
19	"log"
20	"os"
21	"regexp"
22)
23
24func 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 Docker-based build system if we should be.
32	if goos == "linux" {
33		if os.Getenv("GOLANG_SYS_BUILD") != "docker" {
34			os.Stderr.WriteString("In the Docker-based 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 goos == "aix" {
46		// Replace type of Atim, Mtim and Ctim by Timespec in Stat_t
47		// to avoid having both StTimespec and Timespec.
48		sttimespec := regexp.MustCompile(`_Ctype_struct_st_timespec`)
49		b = sttimespec.ReplaceAll(b, []byte("Timespec"))
50	}
51
52	// Intentionally export __val fields in Fsid and Sigset_t
53	valRegex := regexp.MustCompile(`type (Fsid|Sigset_t) struct {(\s+)X__(bits|val)(\s+\S+\s+)}`)
54	b = valRegex.ReplaceAll(b, []byte("type $1 struct {${2}Val$4}"))
55
56	// Intentionally export __fds_bits field in FdSet
57	fdSetRegex := regexp.MustCompile(`type (FdSet) struct {(\s+)X__fds_bits(\s+\S+\s+)}`)
58	b = fdSetRegex.ReplaceAll(b, []byte("type $1 struct {${2}Bits$3}"))
59
60	// Intentionally export __icmp6_filt field in icmpv6_filter
61	icmpV6Regex := regexp.MustCompile(`type (ICMPv6Filter) struct {(\s+)X__icmp6_filt(\s+\S+\s+)}`)
62	b = icmpV6Regex.ReplaceAll(b, []byte("type $1 struct {${2}Filt$3}"))
63
64	// If we have empty Ptrace structs, we should delete them. Only s390x emits
65	// nonempty Ptrace structs.
66	ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`)
67	b = ptraceRexexp.ReplaceAll(b, nil)
68
69	// Replace the control_regs union with a blank identifier for now.
70	controlRegsRegex := regexp.MustCompile(`(Control_regs)\s+\[0\]uint64`)
71	b = controlRegsRegex.ReplaceAll(b, []byte("_ [0]uint64"))
72
73	// Remove fields that are added by glibc
74	// Note that this is unstable as the identifers are private.
75	removeFieldsRegex := regexp.MustCompile(`X__glibc\S*`)
76	b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
77
78	// Convert [65]int8 to [65]byte in Utsname members to simplify
79	// conversion to string; see golang.org/issue/20753
80	convertUtsnameRegex := regexp.MustCompile(`((Sys|Node|Domain)name|Release|Version|Machine)(\s+)\[(\d+)\]u?int8`)
81	b = convertUtsnameRegex.ReplaceAll(b, []byte("$1$3[$4]byte"))
82
83	// Convert [n]int8 to [n]byte in Statvfs_t members to simplify
84	// conversion to string.
85	convertStatvfsRegex := regexp.MustCompile(`((Fstype|Mnton|Mntfrom)name)(\s+)\[(\d+)\]int8`)
86	b = convertStatvfsRegex.ReplaceAll(b, []byte("$1$3[$4]byte"))
87
88	// Convert []int8 to []byte in device mapper ioctl interface
89	convertDmIoctlNames := regexp.MustCompile(`(Name|Uuid|Target_type|Data)(\s+)\[(\d+)\]u?int8`)
90	dmIoctlTypes := regexp.MustCompile(`type Dm(\S+) struct {[^}]*}`)
91	dmStructs := dmIoctlTypes.FindAll(b, -1)
92	for _, s := range dmStructs {
93		newNames := convertDmIoctlNames.ReplaceAll(s, []byte("$1$2[$3]byte"))
94		b = bytes.Replace(b, s, newNames, 1)
95	}
96
97	// Convert []int8 to []byte in ctl_info ioctl interface
98	convertCtlInfoName := regexp.MustCompile(`(Name)(\s+)\[(\d+)\]int8`)
99	ctlInfoType := regexp.MustCompile(`type CtlInfo struct {[^}]*}`)
100	ctlInfoStructs := ctlInfoType.FindAll(b, -1)
101	for _, s := range ctlInfoStructs {
102		newNames := convertCtlInfoName.ReplaceAll(s, []byte("$1$2[$3]byte"))
103		b = bytes.Replace(b, s, newNames, 1)
104	}
105
106	// Convert [1024]int8 to [1024]byte in Ptmget members
107	convertPtmget := regexp.MustCompile(`([SC]n)(\s+)\[(\d+)\]u?int8`)
108	b = convertPtmget.ReplaceAll(b, []byte("$1[$3]byte"))
109
110	// Remove spare fields (e.g. in Statx_t)
111	spareFieldsRegex := regexp.MustCompile(`X__spare\S*`)
112	b = spareFieldsRegex.ReplaceAll(b, []byte("_"))
113
114	// Remove cgo padding fields
115	removePaddingFieldsRegex := regexp.MustCompile(`Pad_cgo_\d+`)
116	b = removePaddingFieldsRegex.ReplaceAll(b, []byte("_"))
117
118	// Remove padding, hidden, or unused fields
119	removeFieldsRegex = regexp.MustCompile(`\b(X_\S+|Padding)`)
120	b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
121
122	// Remove the first line of warning from cgo
123	b = b[bytes.IndexByte(b, '\n')+1:]
124	// Modify the command in the header to include:
125	//  mkpost, our own warning, and a build tag.
126	replacement := fmt.Sprintf(`$1 | go run mkpost.go
127// Code generated by the command above; see README.md. DO NOT EDIT.
128
129// +build %s,%s`, goarch, goos)
130	cgoCommandRegex := regexp.MustCompile(`(cgo -godefs .*)`)
131	b = cgoCommandRegex.ReplaceAll(b, []byte(replacement))
132
133	// Rename Stat_t time fields
134	if goos == "freebsd" && goarch == "386" {
135		// Hide Stat_t.[AMCB]tim_ext fields
136		renameStatTimeExtFieldsRegex := regexp.MustCompile(`[AMCB]tim_ext`)
137		b = renameStatTimeExtFieldsRegex.ReplaceAll(b, []byte("_"))
138	}
139	renameStatTimeFieldsRegex := regexp.MustCompile(`([AMCB])(?:irth)?time?(?:spec)?\s+(Timespec|StTimespec)`)
140	b = renameStatTimeFieldsRegex.ReplaceAll(b, []byte("${1}tim ${2}"))
141
142	// gofmt
143	b, err = format.Source(b)
144	if err != nil {
145		log.Fatal(err)
146	}
147
148	os.Stdout.Write(b)
149}
150