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