1// Copyright 2019 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/*
8 This program reads a file containing function prototypes
9 (like syscall_solaris.go) and generates system call bodies.
10 The prototypes are marked by lines beginning with "//sys"
11 and read like func declarations if //sys is replaced by func, but:
12	* The parameter lists must give a name for each argument.
13	  This includes return parameters.
14	* The parameter lists must give a type for each argument:
15	  the (x, y, z int) shorthand is not allowed.
16	* If the return parameter is an error number, it must be named err.
17	* If go func name needs to be different than its libc name,
18	* or the function is not in libc, name could be specified
19	* at the end, after "=" sign, like
20	  //sys getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt
21*/
22
23package main
24
25import (
26	"bufio"
27	"flag"
28	"fmt"
29	"os"
30	"regexp"
31	"strings"
32)
33
34var (
35	b32     = flag.Bool("b32", false, "32bit big-endian")
36	l32     = flag.Bool("l32", false, "32bit little-endian")
37	tags    = flag.String("tags", "", "build tags")
38	illumos = flag.Bool("illumos", false, "illumos specific code generation")
39)
40
41// cmdLine returns this programs's commandline arguments
42func cmdLine() string {
43	return "go run mksyscall_solaris.go " + strings.Join(os.Args[1:], " ")
44}
45
46// buildTags returns build tags
47func buildTags() string {
48	return *tags
49}
50
51// Param is function parameter
52type Param struct {
53	Name string
54	Type string
55}
56
57// usage prints the program usage
58func usage() {
59	fmt.Fprintf(os.Stderr, "usage: go run mksyscall_solaris.go [-b32 | -l32] [-tags x,y] [file ...]\n")
60	os.Exit(1)
61}
62
63// parseParamList parses parameter list and returns a slice of parameters
64func parseParamList(list string) []string {
65	list = strings.TrimSpace(list)
66	if list == "" {
67		return []string{}
68	}
69	return regexp.MustCompile(`\s*,\s*`).Split(list, -1)
70}
71
72// parseParam splits a parameter into name and type
73func parseParam(p string) Param {
74	ps := regexp.MustCompile(`^(\S*) (\S*)$`).FindStringSubmatch(p)
75	if ps == nil {
76		fmt.Fprintf(os.Stderr, "malformed parameter: %s\n", p)
77		os.Exit(1)
78	}
79	return Param{ps[1], ps[2]}
80}
81
82func main() {
83	flag.Usage = usage
84	flag.Parse()
85	if len(flag.Args()) <= 0 {
86		fmt.Fprintf(os.Stderr, "no files to parse provided\n")
87		usage()
88	}
89
90	endianness := ""
91	if *b32 {
92		endianness = "big-endian"
93	} else if *l32 {
94		endianness = "little-endian"
95	}
96
97	pack := ""
98	text := ""
99	dynimports := ""
100	linknames := ""
101	var vars []string
102	for _, path := range flag.Args() {
103		file, err := os.Open(path)
104		if err != nil {
105			fmt.Fprintf(os.Stderr, err.Error())
106			os.Exit(1)
107		}
108		s := bufio.NewScanner(file)
109		for s.Scan() {
110			t := s.Text()
111			t = strings.TrimSpace(t)
112			t = regexp.MustCompile(`\s+`).ReplaceAllString(t, ` `)
113			if p := regexp.MustCompile(`^package (\S+)$`).FindStringSubmatch(t); p != nil && pack == "" {
114				pack = p[1]
115			}
116			nonblock := regexp.MustCompile(`^\/\/sysnb `).FindStringSubmatch(t)
117			if regexp.MustCompile(`^\/\/sys `).FindStringSubmatch(t) == nil && nonblock == nil {
118				continue
119			}
120
121			// Line must be of the form
122			//	func Open(path string, mode int, perm int) (fd int, err error)
123			// Split into name, in params, out params.
124			f := regexp.MustCompile(`^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$`).FindStringSubmatch(t)
125			if f == nil {
126				fmt.Fprintf(os.Stderr, "%s:%s\nmalformed //sys declaration\n", path, t)
127				os.Exit(1)
128			}
129			funct, inps, outps, modname, sysname := f[2], f[3], f[4], f[5], f[6]
130
131			// Split argument lists on comma.
132			in := parseParamList(inps)
133			out := parseParamList(outps)
134
135			inps = strings.Join(in, ", ")
136			outps = strings.Join(out, ", ")
137
138			// Try in vain to keep people from editing this file.
139			// The theory is that they jump into the middle of the file
140			// without reading the header.
141			text += "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n"
142
143			// So file name.
144			if modname == "" {
145				modname = "libc"
146			}
147
148			// System call name.
149			if sysname == "" {
150				sysname = funct
151			}
152
153			// System call pointer variable name.
154			sysvarname := fmt.Sprintf("proc%s", sysname)
155
156			strconvfunc := "BytePtrFromString"
157			strconvtype := "*byte"
158
159			sysname = strings.ToLower(sysname) // All libc functions are lowercase.
160
161			// Runtime import of function to allow cross-platform builds.
162			dynimports += fmt.Sprintf("//go:cgo_import_dynamic libc_%s %s \"%s.so\"\n", sysname, sysname, modname)
163			// Link symbol to proc address variable.
164			linknames += fmt.Sprintf("//go:linkname %s libc_%s\n", sysvarname, sysname)
165			// Library proc address variable.
166			vars = append(vars, sysvarname)
167
168			// Go function header.
169			outlist := strings.Join(out, ", ")
170			if outlist != "" {
171				outlist = fmt.Sprintf(" (%s)", outlist)
172			}
173			if text != "" {
174				text += "\n"
175			}
176			text += fmt.Sprintf("func %s(%s)%s {\n", funct, strings.Join(in, ", "), outlist)
177
178			// Check if err return available
179			errvar := ""
180			for _, param := range out {
181				p := parseParam(param)
182				if p.Type == "error" {
183					errvar = p.Name
184					continue
185				}
186			}
187
188			// Prepare arguments to Syscall.
189			var args []string
190			n := 0
191			for _, param := range in {
192				p := parseParam(param)
193				if regexp.MustCompile(`^\*`).FindStringSubmatch(p.Type) != nil {
194					args = append(args, "uintptr(unsafe.Pointer("+p.Name+"))")
195				} else if p.Type == "string" && errvar != "" {
196					text += fmt.Sprintf("\tvar _p%d %s\n", n, strconvtype)
197					text += fmt.Sprintf("\t_p%d, %s = %s(%s)\n", n, errvar, strconvfunc, p.Name)
198					text += fmt.Sprintf("\tif %s != nil {\n\t\treturn\n\t}\n", errvar)
199					args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n))
200					n++
201				} else if p.Type == "string" {
202					fmt.Fprintf(os.Stderr, path+":"+funct+" uses string arguments, but has no error return\n")
203					text += fmt.Sprintf("\tvar _p%d %s\n", n, strconvtype)
204					text += fmt.Sprintf("\t_p%d, _ = %s(%s)\n", n, strconvfunc, p.Name)
205					args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n))
206					n++
207				} else if s := regexp.MustCompile(`^\[\](.*)`).FindStringSubmatch(p.Type); s != nil {
208					// Convert slice into pointer, length.
209					// Have to be careful not to take address of &a[0] if len == 0:
210					// pass nil in that case.
211					text += fmt.Sprintf("\tvar _p%d *%s\n", n, s[1])
212					text += fmt.Sprintf("\tif len(%s) > 0 {\n\t\t_p%d = &%s[0]\n\t}\n", p.Name, n, p.Name)
213					args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n), fmt.Sprintf("uintptr(len(%s))", p.Name))
214					n++
215				} else if p.Type == "int64" && endianness != "" {
216					if endianness == "big-endian" {
217						args = append(args, fmt.Sprintf("uintptr(%s>>32)", p.Name), fmt.Sprintf("uintptr(%s)", p.Name))
218					} else {
219						args = append(args, fmt.Sprintf("uintptr(%s)", p.Name), fmt.Sprintf("uintptr(%s>>32)", p.Name))
220					}
221				} else if p.Type == "bool" {
222					text += fmt.Sprintf("\tvar _p%d uint32\n", n)
223					text += fmt.Sprintf("\tif %s {\n\t\t_p%d = 1\n\t} else {\n\t\t_p%d = 0\n\t}\n", p.Name, n, n)
224					args = append(args, fmt.Sprintf("uintptr(_p%d)", n))
225					n++
226				} else {
227					args = append(args, fmt.Sprintf("uintptr(%s)", p.Name))
228				}
229			}
230			nargs := len(args)
231
232			// Determine which form to use; pad args with zeros.
233			asm := "sysvicall6"
234			if nonblock != nil {
235				asm = "rawSysvicall6"
236			}
237			if len(args) <= 6 {
238				for len(args) < 6 {
239					args = append(args, "0")
240				}
241			} else {
242				fmt.Fprintf(os.Stderr, "%s: too many arguments to system call\n", path)
243				os.Exit(1)
244			}
245
246			// Actual call.
247			arglist := strings.Join(args, ", ")
248			call := fmt.Sprintf("%s(uintptr(unsafe.Pointer(&%s)), %d, %s)", asm, sysvarname, nargs, arglist)
249
250			// Assign return values.
251			body := ""
252			ret := []string{"_", "_", "_"}
253			doErrno := false
254			for i := 0; i < len(out); i++ {
255				p := parseParam(out[i])
256				reg := ""
257				if p.Name == "err" {
258					reg = "e1"
259					ret[2] = reg
260					doErrno = true
261				} else {
262					reg = fmt.Sprintf("r%d", i)
263					ret[i] = reg
264				}
265				if p.Type == "bool" {
266					reg = fmt.Sprintf("%d != 0", reg)
267				}
268				if p.Type == "int64" && endianness != "" {
269					// 64-bit number in r1:r0 or r0:r1.
270					if i+2 > len(out) {
271						fmt.Fprintf(os.Stderr, "%s: not enough registers for int64 return\n", path)
272						os.Exit(1)
273					}
274					if endianness == "big-endian" {
275						reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i, i+1)
276					} else {
277						reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i+1, i)
278					}
279					ret[i] = fmt.Sprintf("r%d", i)
280					ret[i+1] = fmt.Sprintf("r%d", i+1)
281				}
282				if reg != "e1" {
283					body += fmt.Sprintf("\t%s = %s(%s)\n", p.Name, p.Type, reg)
284				}
285			}
286			if ret[0] == "_" && ret[1] == "_" && ret[2] == "_" {
287				text += fmt.Sprintf("\t%s\n", call)
288			} else {
289				text += fmt.Sprintf("\t%s, %s, %s := %s\n", ret[0], ret[1], ret[2], call)
290			}
291			text += body
292
293			if doErrno {
294				text += "\tif e1 != 0 {\n"
295				text += "\t\terr = e1\n"
296				text += "\t}\n"
297			}
298			text += "\treturn\n"
299			text += "}\n"
300		}
301		if err := s.Err(); err != nil {
302			fmt.Fprintf(os.Stderr, err.Error())
303			os.Exit(1)
304		}
305		file.Close()
306	}
307	imp := ""
308	if pack != "unix" {
309		imp = "import \"golang.org/x/sys/unix\"\n"
310	}
311
312	syscallimp := ""
313	if !*illumos {
314		syscallimp = "\"syscall\""
315	}
316
317	vardecls := "\t" + strings.Join(vars, ",\n\t")
318	vardecls += " syscallFunc"
319	fmt.Printf(srcTemplate, cmdLine(), buildTags(), pack, syscallimp, imp, dynimports, linknames, vardecls, text)
320}
321
322const srcTemplate = `// %s
323// Code generated by the command above; see README.md. DO NOT EDIT.
324
325// +build %s
326
327package %s
328
329import (
330        "unsafe"
331        %s
332)
333%s
334%s
335%s
336var (
337%s
338)
339
340%s
341`
342