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107c1cdb ND |
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 | ||
23 | package main | |
24 | ||
25 | import ( | |
26 | "bufio" | |
27 | "flag" | |
28 | "fmt" | |
29 | "os" | |
30 | "regexp" | |
31 | "strings" | |
32 | ) | |
33 | ||
34 | var ( | |
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 | ) | |
39 | ||
40 | // cmdLine returns this programs's commandline arguments | |
41 | func cmdLine() string { | |
42 | return "go run mksyscall_solaris.go " + strings.Join(os.Args[1:], " ") | |
43 | } | |
44 | ||
45 | // buildTags returns build tags | |
46 | func buildTags() string { | |
47 | return *tags | |
48 | } | |
49 | ||
50 | // Param is function parameter | |
51 | type Param struct { | |
52 | Name string | |
53 | Type string | |
54 | } | |
55 | ||
56 | // usage prints the program usage | |
57 | func usage() { | |
58 | fmt.Fprintf(os.Stderr, "usage: go run mksyscall_solaris.go [-b32 | -l32] [-tags x,y] [file ...]\n") | |
59 | os.Exit(1) | |
60 | } | |
61 | ||
62 | // parseParamList parses parameter list and returns a slice of parameters | |
63 | func parseParamList(list string) []string { | |
64 | list = strings.TrimSpace(list) | |
65 | if list == "" { | |
66 | return []string{} | |
67 | } | |
68 | return regexp.MustCompile(`\s*,\s*`).Split(list, -1) | |
69 | } | |
70 | ||
71 | // parseParam splits a parameter into name and type | |
72 | func parseParam(p string) Param { | |
73 | ps := regexp.MustCompile(`^(\S*) (\S*)$`).FindStringSubmatch(p) | |
74 | if ps == nil { | |
75 | fmt.Fprintf(os.Stderr, "malformed parameter: %s\n", p) | |
76 | os.Exit(1) | |
77 | } | |
78 | return Param{ps[1], ps[2]} | |
79 | } | |
80 | ||
81 | func main() { | |
82 | flag.Usage = usage | |
83 | flag.Parse() | |
84 | if len(flag.Args()) <= 0 { | |
85 | fmt.Fprintf(os.Stderr, "no files to parse provided\n") | |
86 | usage() | |
87 | } | |
88 | ||
89 | endianness := "" | |
90 | if *b32 { | |
91 | endianness = "big-endian" | |
92 | } else if *l32 { | |
93 | endianness = "little-endian" | |
94 | } | |
95 | ||
96 | pack := "" | |
97 | text := "" | |
98 | dynimports := "" | |
99 | linknames := "" | |
100 | var vars []string | |
101 | for _, path := range flag.Args() { | |
102 | file, err := os.Open(path) | |
103 | if err != nil { | |
104 | fmt.Fprintf(os.Stderr, err.Error()) | |
105 | os.Exit(1) | |
106 | } | |
107 | s := bufio.NewScanner(file) | |
108 | for s.Scan() { | |
109 | t := s.Text() | |
110 | t = strings.TrimSpace(t) | |
111 | t = regexp.MustCompile(`\s+`).ReplaceAllString(t, ` `) | |
112 | if p := regexp.MustCompile(`^package (\S+)$`).FindStringSubmatch(t); p != nil && pack == "" { | |
113 | pack = p[1] | |
114 | } | |
115 | nonblock := regexp.MustCompile(`^\/\/sysnb `).FindStringSubmatch(t) | |
116 | if regexp.MustCompile(`^\/\/sys `).FindStringSubmatch(t) == nil && nonblock == nil { | |
117 | continue | |
118 | } | |
119 | ||
120 | // Line must be of the form | |
121 | // func Open(path string, mode int, perm int) (fd int, err error) | |
122 | // Split into name, in params, out params. | |
123 | f := regexp.MustCompile(`^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$`).FindStringSubmatch(t) | |
124 | if f == nil { | |
125 | fmt.Fprintf(os.Stderr, "%s:%s\nmalformed //sys declaration\n", path, t) | |
126 | os.Exit(1) | |
127 | } | |
128 | funct, inps, outps, modname, sysname := f[2], f[3], f[4], f[5], f[6] | |
129 | ||
130 | // Split argument lists on comma. | |
131 | in := parseParamList(inps) | |
132 | out := parseParamList(outps) | |
133 | ||
134 | inps = strings.Join(in, ", ") | |
135 | outps = strings.Join(out, ", ") | |
136 | ||
137 | // Try in vain to keep people from editing this file. | |
138 | // The theory is that they jump into the middle of the file | |
139 | // without reading the header. | |
140 | text += "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n" | |
141 | ||
142 | // So file name. | |
143 | if modname == "" { | |
144 | modname = "libc" | |
145 | } | |
146 | ||
147 | // System call name. | |
148 | if sysname == "" { | |
149 | sysname = funct | |
150 | } | |
151 | ||
152 | // System call pointer variable name. | |
153 | sysvarname := fmt.Sprintf("proc%s", sysname) | |
154 | ||
155 | strconvfunc := "BytePtrFromString" | |
156 | strconvtype := "*byte" | |
157 | ||
158 | sysname = strings.ToLower(sysname) // All libc functions are lowercase. | |
159 | ||
160 | // Runtime import of function to allow cross-platform builds. | |
161 | dynimports += fmt.Sprintf("//go:cgo_import_dynamic libc_%s %s \"%s.so\"\n", sysname, sysname, modname) | |
162 | // Link symbol to proc address variable. | |
163 | linknames += fmt.Sprintf("//go:linkname %s libc_%s\n", sysvarname, sysname) | |
164 | // Library proc address variable. | |
165 | vars = append(vars, sysvarname) | |
166 | ||
167 | // Go function header. | |
168 | outlist := strings.Join(out, ", ") | |
169 | if outlist != "" { | |
170 | outlist = fmt.Sprintf(" (%s)", outlist) | |
171 | } | |
172 | if text != "" { | |
173 | text += "\n" | |
174 | } | |
175 | text += fmt.Sprintf("func %s(%s)%s {\n", funct, strings.Join(in, ", "), outlist) | |
176 | ||
177 | // Check if err return available | |
178 | errvar := "" | |
179 | for _, param := range out { | |
180 | p := parseParam(param) | |
181 | if p.Type == "error" { | |
182 | errvar = p.Name | |
183 | continue | |
184 | } | |
185 | } | |
186 | ||
187 | // Prepare arguments to Syscall. | |
188 | var args []string | |
189 | n := 0 | |
190 | for _, param := range in { | |
191 | p := parseParam(param) | |
192 | if regexp.MustCompile(`^\*`).FindStringSubmatch(p.Type) != nil { | |
193 | args = append(args, "uintptr(unsafe.Pointer("+p.Name+"))") | |
194 | } else if p.Type == "string" && errvar != "" { | |
195 | text += fmt.Sprintf("\tvar _p%d %s\n", n, strconvtype) | |
196 | text += fmt.Sprintf("\t_p%d, %s = %s(%s)\n", n, errvar, strconvfunc, p.Name) | |
197 | text += fmt.Sprintf("\tif %s != nil {\n\t\treturn\n\t}\n", errvar) | |
198 | args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n)) | |
199 | n++ | |
200 | } else if p.Type == "string" { | |
201 | fmt.Fprintf(os.Stderr, path+":"+funct+" uses string arguments, but has no error return\n") | |
202 | text += fmt.Sprintf("\tvar _p%d %s\n", n, strconvtype) | |
203 | text += fmt.Sprintf("\t_p%d, _ = %s(%s)\n", n, strconvfunc, p.Name) | |
204 | args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n)) | |
205 | n++ | |
206 | } else if s := regexp.MustCompile(`^\[\](.*)`).FindStringSubmatch(p.Type); s != nil { | |
207 | // Convert slice into pointer, length. | |
208 | // Have to be careful not to take address of &a[0] if len == 0: | |
209 | // pass nil in that case. | |
210 | text += fmt.Sprintf("\tvar _p%d *%s\n", n, s[1]) | |
211 | text += fmt.Sprintf("\tif len(%s) > 0 {\n\t\t_p%d = &%s[0]\n\t}\n", p.Name, n, p.Name) | |
212 | args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n), fmt.Sprintf("uintptr(len(%s))", p.Name)) | |
213 | n++ | |
214 | } else if p.Type == "int64" && endianness != "" { | |
215 | if endianness == "big-endian" { | |
216 | args = append(args, fmt.Sprintf("uintptr(%s>>32)", p.Name), fmt.Sprintf("uintptr(%s)", p.Name)) | |
217 | } else { | |
218 | args = append(args, fmt.Sprintf("uintptr(%s)", p.Name), fmt.Sprintf("uintptr(%s>>32)", p.Name)) | |
219 | } | |
220 | } else if p.Type == "bool" { | |
221 | text += fmt.Sprintf("\tvar _p%d uint32\n", n) | |
222 | 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) | |
223 | args = append(args, fmt.Sprintf("uintptr(_p%d)", n)) | |
224 | n++ | |
225 | } else { | |
226 | args = append(args, fmt.Sprintf("uintptr(%s)", p.Name)) | |
227 | } | |
228 | } | |
229 | nargs := len(args) | |
230 | ||
231 | // Determine which form to use; pad args with zeros. | |
232 | asm := "sysvicall6" | |
233 | if nonblock != nil { | |
234 | asm = "rawSysvicall6" | |
235 | } | |
236 | if len(args) <= 6 { | |
237 | for len(args) < 6 { | |
238 | args = append(args, "0") | |
239 | } | |
240 | } else { | |
241 | fmt.Fprintf(os.Stderr, "%s: too many arguments to system call\n", path) | |
242 | os.Exit(1) | |
243 | } | |
244 | ||
245 | // Actual call. | |
246 | arglist := strings.Join(args, ", ") | |
247 | call := fmt.Sprintf("%s(uintptr(unsafe.Pointer(&%s)), %d, %s)", asm, sysvarname, nargs, arglist) | |
248 | ||
249 | // Assign return values. | |
250 | body := "" | |
251 | ret := []string{"_", "_", "_"} | |
252 | doErrno := false | |
253 | for i := 0; i < len(out); i++ { | |
254 | p := parseParam(out[i]) | |
255 | reg := "" | |
256 | if p.Name == "err" { | |
257 | reg = "e1" | |
258 | ret[2] = reg | |
259 | doErrno = true | |
260 | } else { | |
261 | reg = fmt.Sprintf("r%d", i) | |
262 | ret[i] = reg | |
263 | } | |
264 | if p.Type == "bool" { | |
265 | reg = fmt.Sprintf("%d != 0", reg) | |
266 | } | |
267 | if p.Type == "int64" && endianness != "" { | |
268 | // 64-bit number in r1:r0 or r0:r1. | |
269 | if i+2 > len(out) { | |
270 | fmt.Fprintf(os.Stderr, "%s: not enough registers for int64 return\n", path) | |
271 | os.Exit(1) | |
272 | } | |
273 | if endianness == "big-endian" { | |
274 | reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i, i+1) | |
275 | } else { | |
276 | reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i+1, i) | |
277 | } | |
278 | ret[i] = fmt.Sprintf("r%d", i) | |
279 | ret[i+1] = fmt.Sprintf("r%d", i+1) | |
280 | } | |
281 | if reg != "e1" { | |
282 | body += fmt.Sprintf("\t%s = %s(%s)\n", p.Name, p.Type, reg) | |
283 | } | |
284 | } | |
285 | if ret[0] == "_" && ret[1] == "_" && ret[2] == "_" { | |
286 | text += fmt.Sprintf("\t%s\n", call) | |
287 | } else { | |
288 | text += fmt.Sprintf("\t%s, %s, %s := %s\n", ret[0], ret[1], ret[2], call) | |
289 | } | |
290 | text += body | |
291 | ||
292 | if doErrno { | |
293 | text += "\tif e1 != 0 {\n" | |
294 | text += "\t\terr = e1\n" | |
295 | text += "\t}\n" | |
296 | } | |
297 | text += "\treturn\n" | |
298 | text += "}\n" | |
299 | } | |
300 | if err := s.Err(); err != nil { | |
301 | fmt.Fprintf(os.Stderr, err.Error()) | |
302 | os.Exit(1) | |
303 | } | |
304 | file.Close() | |
305 | } | |
306 | imp := "" | |
307 | if pack != "unix" { | |
308 | imp = "import \"golang.org/x/sys/unix\"\n" | |
309 | ||
310 | } | |
311 | vardecls := "\t" + strings.Join(vars, ",\n\t") | |
312 | vardecls += " syscallFunc" | |
313 | fmt.Printf(srcTemplate, cmdLine(), buildTags(), pack, imp, dynimports, linknames, vardecls, text) | |
314 | } | |
315 | ||
316 | const srcTemplate = `// %s | |
317 | // Code generated by the command above; see README.md. DO NOT EDIT. | |
318 | ||
319 | // +build %s | |
320 | ||
321 | package %s | |
322 | ||
323 | import ( | |
324 | "syscall" | |
325 | "unsafe" | |
326 | ) | |
327 | %s | |
328 | %s | |
329 | %s | |
330 | var ( | |
331 | %s | |
332 | ) | |
333 | ||
334 | %s | |
335 | ` |