David K. Bainbridge | bd6b288 | 2021-08-26 13:31:02 +0000 | [diff] [blame] | 1 | // Copyright 2011 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 | // Plan 9 system calls. |
| 6 | // This file is compiled as ordinary Go code, |
| 7 | // but it is also input to mksyscall, |
| 8 | // which parses the //sys lines and generates system call stubs. |
| 9 | // Note that sometimes we use a lowercase //sys name and |
| 10 | // wrap it in our own nicer implementation. |
| 11 | |
| 12 | package plan9 |
| 13 | |
| 14 | import ( |
| 15 | "bytes" |
| 16 | "syscall" |
| 17 | "unsafe" |
| 18 | ) |
| 19 | |
| 20 | // A Note is a string describing a process note. |
| 21 | // It implements the os.Signal interface. |
| 22 | type Note string |
| 23 | |
| 24 | func (n Note) Signal() {} |
| 25 | |
| 26 | func (n Note) String() string { |
| 27 | return string(n) |
| 28 | } |
| 29 | |
| 30 | var ( |
| 31 | Stdin = 0 |
| 32 | Stdout = 1 |
| 33 | Stderr = 2 |
| 34 | ) |
| 35 | |
| 36 | // For testing: clients can set this flag to force |
| 37 | // creation of IPv6 sockets to return EAFNOSUPPORT. |
| 38 | var SocketDisableIPv6 bool |
| 39 | |
| 40 | func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err syscall.ErrorString) |
| 41 | func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err syscall.ErrorString) |
| 42 | func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr) |
| 43 | func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) |
| 44 | |
| 45 | func atoi(b []byte) (n uint) { |
| 46 | n = 0 |
| 47 | for i := 0; i < len(b); i++ { |
| 48 | n = n*10 + uint(b[i]-'0') |
| 49 | } |
| 50 | return |
| 51 | } |
| 52 | |
| 53 | func cstring(s []byte) string { |
| 54 | i := bytes.IndexByte(s, 0) |
| 55 | if i == -1 { |
| 56 | i = len(s) |
| 57 | } |
| 58 | return string(s[:i]) |
| 59 | } |
| 60 | |
| 61 | func errstr() string { |
| 62 | var buf [ERRMAX]byte |
| 63 | |
| 64 | RawSyscall(SYS_ERRSTR, uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)), 0) |
| 65 | |
| 66 | buf[len(buf)-1] = 0 |
| 67 | return cstring(buf[:]) |
| 68 | } |
| 69 | |
| 70 | // Implemented in assembly to import from runtime. |
| 71 | func exit(code int) |
| 72 | |
| 73 | func Exit(code int) { exit(code) } |
| 74 | |
| 75 | func readnum(path string) (uint, error) { |
| 76 | var b [12]byte |
| 77 | |
| 78 | fd, e := Open(path, O_RDONLY) |
| 79 | if e != nil { |
| 80 | return 0, e |
| 81 | } |
| 82 | defer Close(fd) |
| 83 | |
| 84 | n, e := Pread(fd, b[:], 0) |
| 85 | |
| 86 | if e != nil { |
| 87 | return 0, e |
| 88 | } |
| 89 | |
| 90 | m := 0 |
| 91 | for ; m < n && b[m] == ' '; m++ { |
| 92 | } |
| 93 | |
| 94 | return atoi(b[m : n-1]), nil |
| 95 | } |
| 96 | |
| 97 | func Getpid() (pid int) { |
| 98 | n, _ := readnum("#c/pid") |
| 99 | return int(n) |
| 100 | } |
| 101 | |
| 102 | func Getppid() (ppid int) { |
| 103 | n, _ := readnum("#c/ppid") |
| 104 | return int(n) |
| 105 | } |
| 106 | |
| 107 | func Read(fd int, p []byte) (n int, err error) { |
| 108 | return Pread(fd, p, -1) |
| 109 | } |
| 110 | |
| 111 | func Write(fd int, p []byte) (n int, err error) { |
| 112 | return Pwrite(fd, p, -1) |
| 113 | } |
| 114 | |
| 115 | var ioSync int64 |
| 116 | |
| 117 | //sys fd2path(fd int, buf []byte) (err error) |
| 118 | func Fd2path(fd int) (path string, err error) { |
| 119 | var buf [512]byte |
| 120 | |
| 121 | e := fd2path(fd, buf[:]) |
| 122 | if e != nil { |
| 123 | return "", e |
| 124 | } |
| 125 | return cstring(buf[:]), nil |
| 126 | } |
| 127 | |
| 128 | //sys pipe(p *[2]int32) (err error) |
| 129 | func Pipe(p []int) (err error) { |
| 130 | if len(p) != 2 { |
| 131 | return syscall.ErrorString("bad arg in system call") |
| 132 | } |
| 133 | var pp [2]int32 |
| 134 | err = pipe(&pp) |
| 135 | p[0] = int(pp[0]) |
| 136 | p[1] = int(pp[1]) |
| 137 | return |
| 138 | } |
| 139 | |
| 140 | // Underlying system call writes to newoffset via pointer. |
| 141 | // Implemented in assembly to avoid allocation. |
| 142 | func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string) |
| 143 | |
| 144 | func Seek(fd int, offset int64, whence int) (newoffset int64, err error) { |
| 145 | newoffset, e := seek(0, fd, offset, whence) |
| 146 | |
| 147 | if newoffset == -1 { |
| 148 | err = syscall.ErrorString(e) |
| 149 | } |
| 150 | return |
| 151 | } |
| 152 | |
| 153 | func Mkdir(path string, mode uint32) (err error) { |
| 154 | fd, err := Create(path, O_RDONLY, DMDIR|mode) |
| 155 | |
| 156 | if fd != -1 { |
| 157 | Close(fd) |
| 158 | } |
| 159 | |
| 160 | return |
| 161 | } |
| 162 | |
| 163 | type Waitmsg struct { |
| 164 | Pid int |
| 165 | Time [3]uint32 |
| 166 | Msg string |
| 167 | } |
| 168 | |
| 169 | func (w Waitmsg) Exited() bool { return true } |
| 170 | func (w Waitmsg) Signaled() bool { return false } |
| 171 | |
| 172 | func (w Waitmsg) ExitStatus() int { |
| 173 | if len(w.Msg) == 0 { |
| 174 | // a normal exit returns no message |
| 175 | return 0 |
| 176 | } |
| 177 | return 1 |
| 178 | } |
| 179 | |
| 180 | //sys await(s []byte) (n int, err error) |
| 181 | func Await(w *Waitmsg) (err error) { |
| 182 | var buf [512]byte |
| 183 | var f [5][]byte |
| 184 | |
| 185 | n, err := await(buf[:]) |
| 186 | |
| 187 | if err != nil || w == nil { |
| 188 | return |
| 189 | } |
| 190 | |
| 191 | nf := 0 |
| 192 | p := 0 |
| 193 | for i := 0; i < n && nf < len(f)-1; i++ { |
| 194 | if buf[i] == ' ' { |
| 195 | f[nf] = buf[p:i] |
| 196 | p = i + 1 |
| 197 | nf++ |
| 198 | } |
| 199 | } |
| 200 | f[nf] = buf[p:] |
| 201 | nf++ |
| 202 | |
| 203 | if nf != len(f) { |
| 204 | return syscall.ErrorString("invalid wait message") |
| 205 | } |
| 206 | w.Pid = int(atoi(f[0])) |
| 207 | w.Time[0] = uint32(atoi(f[1])) |
| 208 | w.Time[1] = uint32(atoi(f[2])) |
| 209 | w.Time[2] = uint32(atoi(f[3])) |
| 210 | w.Msg = cstring(f[4]) |
| 211 | if w.Msg == "''" { |
| 212 | // await() returns '' for no error |
| 213 | w.Msg = "" |
| 214 | } |
| 215 | return |
| 216 | } |
| 217 | |
| 218 | func Unmount(name, old string) (err error) { |
| 219 | fixwd() |
| 220 | oldp, err := BytePtrFromString(old) |
| 221 | if err != nil { |
| 222 | return err |
| 223 | } |
| 224 | oldptr := uintptr(unsafe.Pointer(oldp)) |
| 225 | |
| 226 | var r0 uintptr |
| 227 | var e syscall.ErrorString |
| 228 | |
| 229 | // bind(2) man page: If name is zero, everything bound or mounted upon old is unbound or unmounted. |
| 230 | if name == "" { |
| 231 | r0, _, e = Syscall(SYS_UNMOUNT, _zero, oldptr, 0) |
| 232 | } else { |
| 233 | namep, err := BytePtrFromString(name) |
| 234 | if err != nil { |
| 235 | return err |
| 236 | } |
| 237 | r0, _, e = Syscall(SYS_UNMOUNT, uintptr(unsafe.Pointer(namep)), oldptr, 0) |
| 238 | } |
| 239 | |
| 240 | if int32(r0) == -1 { |
| 241 | err = e |
| 242 | } |
| 243 | return |
| 244 | } |
| 245 | |
| 246 | func Fchdir(fd int) (err error) { |
| 247 | path, err := Fd2path(fd) |
| 248 | |
| 249 | if err != nil { |
| 250 | return |
| 251 | } |
| 252 | |
| 253 | return Chdir(path) |
| 254 | } |
| 255 | |
| 256 | type Timespec struct { |
| 257 | Sec int32 |
| 258 | Nsec int32 |
| 259 | } |
| 260 | |
| 261 | type Timeval struct { |
| 262 | Sec int32 |
| 263 | Usec int32 |
| 264 | } |
| 265 | |
| 266 | func NsecToTimeval(nsec int64) (tv Timeval) { |
| 267 | nsec += 999 // round up to microsecond |
| 268 | tv.Usec = int32(nsec % 1e9 / 1e3) |
| 269 | tv.Sec = int32(nsec / 1e9) |
| 270 | return |
| 271 | } |
| 272 | |
| 273 | func nsec() int64 { |
| 274 | var scratch int64 |
| 275 | |
| 276 | r0, _, _ := Syscall(SYS_NSEC, uintptr(unsafe.Pointer(&scratch)), 0, 0) |
| 277 | // TODO(aram): remove hack after I fix _nsec in the pc64 kernel. |
| 278 | if r0 == 0 { |
| 279 | return scratch |
| 280 | } |
| 281 | return int64(r0) |
| 282 | } |
| 283 | |
| 284 | func Gettimeofday(tv *Timeval) error { |
| 285 | nsec := nsec() |
| 286 | *tv = NsecToTimeval(nsec) |
| 287 | return nil |
| 288 | } |
| 289 | |
| 290 | func Getpagesize() int { return 0x1000 } |
| 291 | |
| 292 | func Getegid() (egid int) { return -1 } |
| 293 | func Geteuid() (euid int) { return -1 } |
| 294 | func Getgid() (gid int) { return -1 } |
| 295 | func Getuid() (uid int) { return -1 } |
| 296 | |
| 297 | func Getgroups() (gids []int, err error) { |
| 298 | return make([]int, 0), nil |
| 299 | } |
| 300 | |
| 301 | //sys open(path string, mode int) (fd int, err error) |
| 302 | func Open(path string, mode int) (fd int, err error) { |
| 303 | fixwd() |
| 304 | return open(path, mode) |
| 305 | } |
| 306 | |
| 307 | //sys create(path string, mode int, perm uint32) (fd int, err error) |
| 308 | func Create(path string, mode int, perm uint32) (fd int, err error) { |
| 309 | fixwd() |
| 310 | return create(path, mode, perm) |
| 311 | } |
| 312 | |
| 313 | //sys remove(path string) (err error) |
| 314 | func Remove(path string) error { |
| 315 | fixwd() |
| 316 | return remove(path) |
| 317 | } |
| 318 | |
| 319 | //sys stat(path string, edir []byte) (n int, err error) |
| 320 | func Stat(path string, edir []byte) (n int, err error) { |
| 321 | fixwd() |
| 322 | return stat(path, edir) |
| 323 | } |
| 324 | |
| 325 | //sys bind(name string, old string, flag int) (err error) |
| 326 | func Bind(name string, old string, flag int) (err error) { |
| 327 | fixwd() |
| 328 | return bind(name, old, flag) |
| 329 | } |
| 330 | |
| 331 | //sys mount(fd int, afd int, old string, flag int, aname string) (err error) |
| 332 | func Mount(fd int, afd int, old string, flag int, aname string) (err error) { |
| 333 | fixwd() |
| 334 | return mount(fd, afd, old, flag, aname) |
| 335 | } |
| 336 | |
| 337 | //sys wstat(path string, edir []byte) (err error) |
| 338 | func Wstat(path string, edir []byte) (err error) { |
| 339 | fixwd() |
| 340 | return wstat(path, edir) |
| 341 | } |
| 342 | |
| 343 | //sys chdir(path string) (err error) |
| 344 | //sys Dup(oldfd int, newfd int) (fd int, err error) |
| 345 | //sys Pread(fd int, p []byte, offset int64) (n int, err error) |
| 346 | //sys Pwrite(fd int, p []byte, offset int64) (n int, err error) |
| 347 | //sys Close(fd int) (err error) |
| 348 | //sys Fstat(fd int, edir []byte) (n int, err error) |
| 349 | //sys Fwstat(fd int, edir []byte) (err error) |