mirror of
https://github.com/golang/go
synced 2024-11-26 07:27:59 -07:00
533 lines
11 KiB
Go
533 lines
11 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// SRPC constants, data structures, and parsing.
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package srpc
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import (
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"bytes";
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"math";
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"os";
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"strconv";
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"syscall";
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"unsafe";
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)
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// An Errno is an SRPC status code.
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type Errno uint32
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const (
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OK Errno = 256 + iota;
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ErrBreak;
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ErrMessageTruncated;
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ErrNoMemory;
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ErrProtocolMismatch;
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ErrBadRPCNumber;
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ErrBadArgType;
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ErrTooFewArgs;
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ErrTooManyArgs;
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ErrInArgTypeMismatch;
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ErrOutArgTypeMismatch;
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ErrInternalError;
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ErrAppError;
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)
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var errstr = [...]string {
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OK-OK: "ok",
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ErrBreak-OK: "break",
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ErrMessageTruncated-OK: "message truncated",
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ErrNoMemory-OK: "out of memory",
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ErrProtocolMismatch-OK: "protocol mismatch",
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ErrBadRPCNumber-OK: "invalid RPC method number",
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ErrBadArgType-OK: "unexpected argument type",
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ErrTooFewArgs-OK: "too few arguments",
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ErrTooManyArgs-OK: "too many arguments",
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ErrInArgTypeMismatch-OK: "input argument type mismatch",
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ErrOutArgTypeMismatch-OK: "output argument type mismatch",
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ErrInternalError-OK: "internal error",
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ErrAppError-OK: "application error",
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}
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func (e Errno) String() string {
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if e < OK || int(e-OK) >= len(errstr) {
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return "Errno(" + strconv.Itoa64(int64(e)) + ")"
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}
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return errstr[e - OK];
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}
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// A *msgHdr is the data argument to the imc_recvmsg
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// and imc_sendmsg system calls. Because it contains unchecked
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// counts trusted by the system calls, the data structure is unsafe
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// to expose to package clients.
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type msgHdr struct {
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iov *iov;
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niov int32;
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desc *int32;
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ndesc int32;
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flags uint32;
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}
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// A single region for I/O. Just as unsafe as msgHdr.
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type iov struct {
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base *byte;
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len int32;
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}
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// A msg is the Go representation of a message.
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type msg struct {
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rdata []byte; // data being consumed during message parsing
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rdesc []int32; // file descriptors being consumed during message parsing
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wdata []byte; // data being generated when replying
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// parsed version of message
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protocol uint32;
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requestId uint64;
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isReq bool;
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rpcNumber uint32;
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gotHeader bool;
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status Errno; // error code sent in response
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Arg []interface{}; // method arguments
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Ret []interface{}; // method results
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Size []int; // max sizes for arrays in method results
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fmt string; // accumulated format string of arg+":"+ret
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}
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// A msgReceiver receives messages from a file descriptor.
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type msgReceiver struct {
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fd int;
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data [128*1024]byte;
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desc [8]int32;
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hdr msgHdr;
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iov iov;
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}
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func (r *msgReceiver) recv() (*msg, os.Error) {
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// Init pointers to buffers where syscall recvmsg can write.
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r.iov.base = &r.data[0];
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r.iov.len = int32(len(r.data));
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r.hdr.iov = &r.iov;
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r.hdr.niov = 1;
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r.hdr.desc = &r.desc[0];
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r.hdr.ndesc = int32(len(r.desc));
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n, _, e := syscall.Syscall(syscall.SYS_IMC_RECVMSG, uintptr(r.fd), uintptr(unsafe.Pointer(&r.hdr)), 0);
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if e != 0 {
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return nil, os.NewSyscallError("imc_recvmsg", int(e));
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}
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// Make a copy of the data so that the next recvmsg doesn't
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// smash it. The system call did not update r.iov.len. Instead it
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// returned the total byte count as n.
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m := new(msg);
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m.rdata = make([]byte, n);
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bytes.Copy(m.rdata, &r.data);
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// Make a copy of the desc too.
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// The system call *did* update r.hdr.ndesc.
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if r.hdr.ndesc > 0 {
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m.rdesc = make([]int32, r.hdr.ndesc);
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for i := range m.rdesc {
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m.rdesc[i] = r.desc[i];
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}
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}
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return m, nil;
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}
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// A msgSender sends messages on a file descriptor.
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type msgSender struct {
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fd int;
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hdr msgHdr;
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iov iov;
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}
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func (s *msgSender) send(m *msg) os.Error {
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if len(m.wdata) > 0 {
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s.iov.base = &m.wdata[0];
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}
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s.iov.len = int32(len(m.wdata));
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s.hdr.iov = &s.iov;
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s.hdr.niov = 1;
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s.hdr.desc = nil;
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s.hdr.ndesc = 0;
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_, _, e := syscall.Syscall(syscall.SYS_IMC_SENDMSG, uintptr(s.fd), uintptr(unsafe.Pointer(&s.hdr)), 0);
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if e != 0 {
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return os.NewSyscallError("imc_sendmsg", int(e));
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}
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return nil;
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}
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// Reading from msg.rdata.
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func (m *msg) uint8() uint8 {
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if m.status != OK {
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return 0;
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}
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if len(m.rdata) < 1 {
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m.status = ErrMessageTruncated;
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return 0;
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}
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x := m.rdata[0];
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m.rdata = m.rdata[1:len(m.rdata)];
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return x;
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}
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func (m *msg) uint32() uint32 {
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if m.status != OK {
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return 0;
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}
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if len(m.rdata) < 4 {
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m.status = ErrMessageTruncated;
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return 0;
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}
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b := m.rdata[0:4];
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x := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24;
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m.rdata = m.rdata[4:len(m.rdata)];
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return x;
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}
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func (m *msg) uint64() uint64 {
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if m.status != OK {
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return 0;
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}
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if len(m.rdata) < 8 {
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m.status = ErrMessageTruncated;
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return 0;
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}
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b := m.rdata[0:8];
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x := uint64(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24);
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x |= uint64(uint32(b[4]) | uint32(b[5])<<8 | uint32(b[6])<<16 | uint32(b[7])<<24)<<32;
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m.rdata = m.rdata[8:len(m.rdata)];
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return x;
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}
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func (m *msg) bytes(n int) []byte {
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if m.status != OK {
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return nil;
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}
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if len(m.rdata) < n {
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m.status = ErrMessageTruncated;
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return nil;
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}
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x := m.rdata[0:n];
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m.rdata = m.rdata[n:len(m.rdata)];
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return x;
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}
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// Writing to msg.wdata.
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func (m *msg) grow(n int) []byte {
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i := len(m.wdata);
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if i+n > cap(m.wdata) {
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a := make([]byte, i, (i+n)*2);
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bytes.Copy(a, m.wdata);
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m.wdata = a;
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}
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m.wdata = m.wdata[0:i+n];
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return m.wdata[i:i+n];
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}
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func (m *msg) wuint8(x uint8) {
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m.grow(1)[0] = x;
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}
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func (m *msg) wuint32(x uint32) {
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b := m.grow(4);
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b[0] = byte(x);
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b[1] = byte(x>>8);
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b[2] = byte(x>>16);
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b[3] = byte(x>>24);
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}
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func (m *msg) wuint64(x uint64) {
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b := m.grow(8);
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lo := uint32(x);
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b[0] = byte(lo);
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b[1] = byte(lo>>8);
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b[2] = byte(lo>>16);
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b[3] = byte(lo>>24);
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hi := uint32(x>>32);
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b[4] = byte(hi);
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b[5] = byte(hi>>8);
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b[6] = byte(hi>>16);
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b[7] = byte(hi>>24);
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}
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func (m *msg) wbytes(p []byte) {
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bytes.Copy(m.grow(len(p)), p);
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}
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func (m *msg) wstring(s string) {
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b := m.grow(len(s));
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for i := range b {
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b[i] = s[i];
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}
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}
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// Parsing of RPC header and arguments.
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//
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// The header format is:
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// protocol uint32;
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// requestId uint64;
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// isReq bool;
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// rpcNumber uint32;
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// status uint32; // only for response
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//
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// Then a sequence of values follow, preceded by the length:
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// nvalue uint32;
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//
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// Each value begins with a one-byte type followed by
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// type-specific data.
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//
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// type uint8;
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// 'b': x bool;
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// 'C': len uint32; x [len]byte;
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// 'd': x float64;
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// 'D': len uint32; x [len]float64;
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// 'h': x int; // handle aka file descriptor
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// 'i': x int32;
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// 'I': len uint32; x [len]int32;
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// 's': len uint32; x [len]byte;
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//
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// If this is a request, a sequence of pseudo-values follows,
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// preceded by its length (nvalue uint32).
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//
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// Each pseudo-value is a one-byte type as above,
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// followed by a maximum length (len uint32)
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// for the 'C', 'D', 'I', and 's' types.
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//
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// In the Go msg, we represent each argument by
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// an empty interface containing the type of x in the
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// corresponding case.
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// The current protocol number.
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const protocol = 0xc0da0002
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func (m *msg) unpackHeader() {
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m.protocol = m.uint32();
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m.requestId = m.uint64();
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m.isReq = m.uint8() != 0;
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m.rpcNumber = m.uint32();
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m.gotHeader = m.status == OK; // signal that header parsed successfully
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if m.gotHeader && !m.isReq {
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status := Errno(m.uint32());
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m.gotHeader = m.status == OK; // still ok?
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if m.gotHeader {
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m.status = status;
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}
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}
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}
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func (m *msg) packHeader() {
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m.wuint32(m.protocol);
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m.wuint64(m.requestId);
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if m.isReq {
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m.wuint8(1);
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} else {
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m.wuint8(0);
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}
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m.wuint32(m.rpcNumber);
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if !m.isReq {
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m.wuint32(uint32(m.status));
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}
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}
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func (m *msg) unpackValues(v []interface{}) {
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for i := range v {
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t := m.uint8();
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m.fmt += string(t);
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switch t {
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default:
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if m.status == OK {
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m.status = ErrBadArgType;
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}
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return;
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case 'b': // bool[1]
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v[i] = m.uint8() > 0;
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case 'C': // char array
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v[i] = m.bytes(int(m.uint32()));
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case 'd': // double
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v[i] = math.Float64frombits(m.uint64());
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case 'D': // double array
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a := make([]float64, int(m.uint32()));
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for j := range a {
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a[j] = math.Float64frombits(m.uint64());
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}
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v[i] = a;
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case 'h': // file descriptor (handle)
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if len(m.rdesc) == 0 {
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if m.status == OK {
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m.status = ErrBadArgType;
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}
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return;
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}
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v[i] = int(m.rdesc[0]);
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m.rdesc = m.rdesc[1:len(m.rdesc)];
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case 'i': // int
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v[i] = int32(m.uint32());
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case 'I': // int array
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a := make([]int32, int(m.uint32()));
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for j := range a {
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a[j] = int32(m.uint32());
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}
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v[i] = a;
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case 's': // string
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v[i] = string(m.bytes(int(m.uint32())));
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}
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}
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}
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func (m *msg) packValues(v []interface{}) {
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for i := range v {
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switch x := v[i].(type) {
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default:
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if m.status == OK {
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m.status = ErrInternalError;
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}
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return;
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case bool:
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m.wuint8('b');
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if x {
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m.wuint8(1);
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} else {
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m.wuint8(0);
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}
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case []byte:
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m.wuint8('C');
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m.wuint32(uint32(len(x)));
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m.wbytes(x);
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case float64:
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m.wuint8('d');
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m.wuint64(math.Float64bits(x));
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case []float64:
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m.wuint8('D');
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m.wuint32(uint32(len(x)));
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for _, f := range x {
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m.wuint64(math.Float64bits(f));
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}
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case int32:
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m.wuint8('i');
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m.wuint32(uint32(x));
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case []int32:
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m.wuint8('I');
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m.wuint32(uint32(len(x)));
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for _, i := range x {
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m.wuint32(uint32(i));
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}
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case string:
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m.wuint8('s');
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m.wuint32(uint32(len(x)));
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m.wstring(x);
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}
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}
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}
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func (m *msg) unpackRequest() {
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m.status = OK;
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if m.unpackHeader(); m.status != OK {
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return;
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}
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if m.protocol != protocol || !m.isReq {
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m.status = ErrProtocolMismatch;
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return;
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}
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// type-tagged argument values
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m.Arg = make([]interface{}, m.uint32());
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m.unpackValues(m.Arg);
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if m.status != OK {
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return;
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}
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// type-tagged expected return sizes.
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// fill in zero values for each return value
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// and save sizes.
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m.fmt += ":";
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m.Ret = make([]interface{}, m.uint32());
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m.Size = make([]int, len(m.Ret));
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for i := range m.Ret {
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t := m.uint8();
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m.fmt += string(t);
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switch t {
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default:
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if m.status == OK {
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m.status = ErrBadArgType;
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}
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return;
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case 'b': // bool[1]
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m.Ret[i] = false;
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case 'C': // char array
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m.Size[i] = int(m.uint32());
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m.Ret[i] = []byte(nil);
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case 'd': // double
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m.Ret[i] = float64(0);
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case 'D': // double array
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m.Size[i] = int(m.uint32());
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m.Ret[i] = []float64(nil);
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case 'h': // file descriptor (handle)
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m.Ret[i] = int(-1);
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case 'i': // int
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m.Ret[i] = int32(0);
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case 'I': // int array
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m.Size[i] = int(m.uint32());
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m.Ret[i] = []int32(nil);
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case 's': // string
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m.Size[i] = int(m.uint32());
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m.Ret[i] = "";
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}
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}
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}
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func (m *msg) packRequest() {
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m.packHeader();
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m.wuint32(uint32(len(m.Arg)));
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m.packValues(m.Arg);
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m.wuint32(uint32(len(m.Ret)));
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for i, v := range m.Ret {
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switch x := v.(type) {
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case bool:
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m.wuint8('b');
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case []byte:
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m.wuint8('C');
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m.wuint32(uint32(m.Size[i]));
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case float64:
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m.wuint8('d');
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case []float64:
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m.wuint8('D');
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m.wuint32(uint32(m.Size[i]));
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case int:
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m.wuint8('h');
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case int32:
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m.wuint8('i');
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case []int32:
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m.wuint8('I');
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m.wuint32(uint32(m.Size[i]));
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case string:
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m.wuint8('s');
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m.wuint32(uint32(m.Size[i]));
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}
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}
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}
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func (m *msg) unpackResponse() {
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m.status = OK;
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if m.unpackHeader(); m.status != OK {
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return;
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}
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if m.protocol != protocol || m.isReq {
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m.status = ErrProtocolMismatch;
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return;
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}
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// type-tagged return values
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m.fmt = "";
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m.Ret = make([]interface{}, m.uint32());
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m.unpackValues(m.Ret);
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}
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func (m *msg) packResponse() {
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m.packHeader();
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m.wuint32(uint32(len(m.Ret)));
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m.packValues(m.Ret);
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|
}
|
|
|