forked from u-root/u-root
/
syscall_linux.go
368 lines (334 loc) · 11.8 KB
/
syscall_linux.go
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// Copyright 2018 Google LLC.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package strace
import (
"encoding/binary"
"fmt"
"os"
"strconv"
"syscall"
"time"
"github.com/u-root/u-root/pkg/abi"
"golang.org/x/sys/unix"
)
func path(t *Tracer, addr Addr) string {
path, err := t.ReadString(addr, unix.PathMax)
if err != nil {
return fmt.Sprintf("%#x (error decoding path: %s)", addr, err)
}
return fmt.Sprintf("%#x %s", addr, path)
}
func utimensTimespec(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var tim unix.Timespec
if _, err := t.Read(addr, &tim); err != nil {
return fmt.Sprintf("%#x (error decoding timespec: %s)", addr, err)
}
var ns string
switch tim.Nsec {
case unix.UTIME_NOW:
ns = "UTIME_NOW"
case unix.UTIME_OMIT:
ns = "UTIME_OMIT"
default:
ns = fmt.Sprintf("%v", tim.Nsec)
}
return fmt.Sprintf("%#x {sec=%v nsec=%s}", addr, tim.Sec, ns)
}
func timespec(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var tim unix.Timespec
if _, err := t.Read(addr, &tim); err != nil {
return fmt.Sprintf("%#x (error decoding timespec: %s)", addr, err)
}
return fmt.Sprintf("%#x {sec=%v nsec=%v}", addr, tim.Sec, tim.Nsec)
}
func timeval(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var tim unix.Timeval
if _, err := t.Read(addr, &tim); err != nil {
return fmt.Sprintf("%#x (error decoding timeval: %s)", addr, err)
}
return fmt.Sprintf("%#x {sec=%v usec=%v}", addr, tim.Sec, tim.Usec)
}
func utimbuf(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var utim syscall.Utimbuf
if _, err := t.Read(addr, &utim); err != nil {
return fmt.Sprintf("%#x (error decoding utimbuf: %s)", addr, err)
}
return fmt.Sprintf("%#x {actime=%v, modtime=%v}", addr, utim.Actime, utim.Modtime)
}
func fileMode(mode uint32) string {
return fmt.Sprintf("%#09o", mode&0x1ff)
}
func stat(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var stat unix.Stat_t
if _, err := t.Read(addr, &stat); err != nil {
return fmt.Sprintf("%#x (error decoding stat: %s)", addr, err)
}
return fmt.Sprintf("%#x {dev=%d, ino=%d, mode=%s, nlink=%d, uid=%d, gid=%d, rdev=%d, size=%d, blksize=%d, blocks=%d, atime=%s, mtime=%s, ctime=%s}", addr, stat.Dev, stat.Ino, fileMode(stat.Mode), stat.Nlink, stat.Uid, stat.Gid, stat.Rdev, stat.Size, stat.Blksize, stat.Blocks, time.Unix(int64(stat.Atim.Sec), int64(stat.Atim.Nsec)), time.Unix(int64(stat.Mtim.Sec), int64(stat.Mtim.Nsec)), time.Unix(int64(stat.Ctim.Sec), int64(stat.Ctim.Nsec)))
}
func itimerval(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
interval := timeval(t, addr)
value := timeval(t, addr+Addr(binary.Size(unix.Timeval{})))
return fmt.Sprintf("%#x {interval=%s, value=%s}", addr, interval, value)
}
func itimerspec(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
interval := timespec(t, addr)
value := timespec(t, addr+Addr(binary.Size(unix.Timespec{})))
return fmt.Sprintf("%#x {interval=%s, value=%s}", addr, interval, value)
}
func stringVector(t *Tracer, addr Addr) string {
vs, err := t.ReadStringVector(addr, ExecMaxElemSize, ExecMaxTotalSize)
if err != nil {
return fmt.Sprintf("%#x {error copying vector: %v}", addr, err)
}
return fmt.Sprintf("%q", vs)
/*
vec := []string{}
s := fmt.Sprintf("%#x [", addr)
for i, v := range vec {
if i != 0 {
s += ", "
}
s += fmt.Sprintf("%q", v)
}
s += "]"
return s
*/
}
func rusage(t *Tracer, addr Addr) string {
if addr == 0 {
return "null"
}
var ru unix.Rusage
if _, err := t.Read(addr, &ru); err != nil {
return fmt.Sprintf("%#x (error decoding rusage: %s)", addr, err)
}
return fmt.Sprintf("%#x %+v", addr, ru)
}
// pre fills in the pre-execution arguments for a system call. If an argument
// cannot be interpreted before the system call is executed, then a hex value
// will be used. Note that a full output slice will always be provided, that is
// len(return) == len(args).
func (i *SyscallInfo) pre(t *Tracer, r *TraceRecord, maximumBlobSize uint) []string {
var output []string
args := r.Args
for arg := range args {
if arg >= len(i.format) {
break
}
switch i.format[arg] {
case WriteBuffer:
output = append(output, dump(t, args[arg].Pointer(), args[arg+1].SizeT(), maximumBlobSize))
case WriteIOVec:
output = append(output, iovecs(t, args[arg].Pointer(), int(args[arg+1].Int()), true /* content */, uint64(maximumBlobSize)))
case IOVec:
output = append(output, iovecs(t, args[arg].Pointer(), int(args[arg+1].Int()), false /* content */, uint64(maximumBlobSize)))
case SendMsgHdr:
output = append(output, msghdr(t, args[arg].Pointer(), true /* content */, uint64(maximumBlobSize)))
case RecvMsgHdr:
output = append(output, msghdr(t, args[arg].Pointer(), false /* content */, uint64(maximumBlobSize)))
case Path:
output = append(output, path(t, args[arg].Pointer()))
case ExecveStringVector:
output = append(output, stringVector(t, args[arg].Pointer()))
case SockAddr:
output = append(output, sockAddr(t, args[arg].Pointer(), uint32(args[arg+1].Uint64())))
case SockLen:
output = append(output, sockLenPointer(t, args[arg].Pointer()))
case SockFamily:
output = append(output, abi.SocketFamily.Parse(uint64(args[arg].Int())))
case SockType:
output = append(output, abi.SockType(args[arg].Int()))
case SockProtocol:
output = append(output, abi.SockProtocol(args[arg-2].Int(), args[arg].Int()))
case SockFlags:
output = append(output, abi.SockFlags(args[arg].Int()))
case Timespec:
output = append(output, timespec(t, args[arg].Pointer()))
case UTimeTimespec:
output = append(output, utimensTimespec(t, args[arg].Pointer()))
case ItimerVal:
output = append(output, itimerval(t, args[arg].Pointer()))
case ItimerSpec:
output = append(output, itimerspec(t, args[arg].Pointer()))
case Timeval:
output = append(output, timeval(t, args[arg].Pointer()))
case Utimbuf:
output = append(output, utimbuf(t, args[arg].Pointer()))
case CloneFlags:
output = append(output, abi.CloneFlagSet.Parse(uint64(args[arg].Uint())))
case OpenFlags:
output = append(output, abi.Open(uint64(args[arg].Uint())))
case Mode:
output = append(output, os.FileMode(args[arg].Uint()).String())
case FutexOp:
output = append(output, abi.Futex(uint64(args[arg].Uint())))
case PtraceRequest:
output = append(output, abi.PtraceRequestSet.Parse(args[arg].Uint64()))
case ItimerType:
output = append(output, abi.ItimerTypes.Parse(uint64(args[arg].Int())))
case Oct:
output = append(output, "0o"+strconv.FormatUint(args[arg].Uint64(), 8))
case Hex:
fallthrough
default:
output = append(output, "0x"+strconv.FormatUint(args[arg].Uint64(), 16))
}
}
return output
}
// post fills in the post-execution arguments for a system call. This modifies
// the given output slice in place with arguments that may only be interpreted
// after the system call has been executed.
func (i *SyscallInfo) post(t *Tracer, args SyscallArguments, rval SyscallArgument, output []string, maximumBlobSize uint) {
for arg := range output {
if arg >= len(i.format) {
break
}
switch i.format[arg] {
case ReadBuffer:
output[arg] = dump(t, args[arg].Pointer(), uint(rval.Uint64()), maximumBlobSize)
case ReadIOVec:
printLength := rval.Uint()
if printLength > uint32(maximumBlobSize) {
printLength = uint32(maximumBlobSize)
}
output[arg] = iovecs(t, args[arg].Pointer(), int(args[arg+1].Int()), true /* content */, uint64(printLength))
case WriteIOVec, IOVec, WriteBuffer:
// We already have a big blast from write.
output[arg] = "..."
case SendMsgHdr:
output[arg] = msghdr(t, args[arg].Pointer(), false /* content */, uint64(maximumBlobSize))
case RecvMsgHdr:
output[arg] = msghdr(t, args[arg].Pointer(), true /* content */, uint64(maximumBlobSize))
case PostPath:
output[arg] = path(t, args[arg].Pointer())
case PipeFDs:
output[arg] = fdpair(t, args[arg].Pointer())
case Uname:
output[arg] = uname(t, args[arg].Pointer())
case Stat:
output[arg] = stat(t, args[arg].Pointer())
case PostSockAddr:
output[arg] = postSockAddr(t, args[arg].Pointer(), args[arg+1].Pointer())
case SockLen:
output[arg] = sockLenPointer(t, args[arg].Pointer())
case PostTimespec:
output[arg] = timespec(t, args[arg].Pointer())
case PostItimerVal:
output[arg] = itimerval(t, args[arg].Pointer())
case PostItimerSpec:
output[arg] = itimerspec(t, args[arg].Pointer())
case Timeval:
output[arg] = timeval(t, args[arg].Pointer())
case Rusage:
output[arg] = rusage(t, args[arg].Pointer())
}
}
}
// printEntry prints the given system call entry.
func (i *SyscallInfo) printEnter(t *Tracer, r *TraceRecord) string {
t.output = i.pre(t, r, LogMaximumSize)
o := t.output
switch len(o) {
case 0:
return fmt.Sprintf("%s E %s()", t.Name, i.name)
case 1:
return fmt.Sprintf("%s E %s(%s)", t.Name, i.name, o[0])
case 2:
return fmt.Sprintf("%s E %s(%s, %s)", t.Name, i.name, o[0], o[1])
case 3:
return fmt.Sprintf("%s E %s(%s, %s, %s)", t.Name, i.name, o[0], o[1], o[2])
case 4:
return fmt.Sprintf("%s E %s(%s, %s, %s, %s)", t.Name, i.name, o[0], o[1], o[2], o[3])
case 5:
return fmt.Sprintf("%s E %s(%s, %s, %s, %s, %s)", t.Name, i.name, o[0], o[1], o[2], o[3], o[4])
case 6:
return fmt.Sprintf("%s E %s(%s, %s, %s, %s, %s, %s)", t.Name, i.name, o[0], o[1], o[2], o[3], o[4], o[5])
default:
return fmt.Sprintf("%s E %s(%s, %s, %s, %s, %s, %s, ...)", t.Name, i.name, o[0], o[1], o[2], o[3], o[4], o[5])
}
}
func sysCallEnter(t *Tracer, r *TraceRecord) {
i := defaultSyscallInfo(r.Sysno)
if v, ok := syscalls[uintptr(r.Sysno)]; ok {
*i = v
}
r.Out = i.printEnter(t, r)
}
func sysCallExit(t *Tracer, r *TraceRecord) {
i := defaultSyscallInfo(r.Sysno)
if v, ok := syscalls[uintptr(r.Sysno)]; ok {
*i = v
}
r.Out = i.printExit(t, r.Time, r.Args, r.Ret[0], r.Err, r.Errno)
}
// SysCall takes a Tracer and a TraceRecord and adds prettyprint to the TraceRecord.
func SysCall(t *Tracer, r *TraceRecord) {
if r.EX == Enter {
sysCallEnter(t, r)
return
}
sysCallExit(t, r)
}
// printExit prints the given system call exit.
func (i *SyscallInfo) printExit(t *Tracer, elapsed time.Duration, args SyscallArguments, retval SyscallArgument, err error, errno int) string {
o := t.output
var rval string
if err == nil {
// Fill in the output after successful execution.
i.post(t, args, retval, o, LogMaximumSize)
rval = fmt.Sprintf("%#x (%v)", retval, elapsed)
} else {
rval = fmt.Sprintf("%#x errno=%d (%s) (%v)", retval, errno, err, elapsed)
}
switch len(o) {
case 0:
return fmt.Sprintf("%s X %s() = %s", t.Name, i.name, rval)
case 1:
return fmt.Sprintf("%s X %s(%s) = %s", t.Name, i.name, o[0], rval)
case 2:
return fmt.Sprintf("%s X %s(%s, %s) = %s", t.Name, i.name, o[0], o[1], rval)
case 3:
return fmt.Sprintf("%s X %s(%s, %s, %s) = %s", t.Name, i.name, o[0], o[1], o[2], rval)
case 4:
return fmt.Sprintf("%s X %s(%s, %s, %s, %s) = %s", t.Name, i.name, o[0], o[1], o[2], o[3], rval)
case 5:
return fmt.Sprintf("%s X %s(%s, %s, %s, %s, %s) = %s", t.Name, i.name, o[0], o[1], o[2], o[3], o[4], rval)
case 6:
return fmt.Sprintf("%s X %s(%s, %s, %s, %s, %s, %s) = %s", t.Name, i.name, o[0], o[1], o[2], o[3], o[4], o[5], rval)
default:
return fmt.Sprintf("%s X %s(%s, %s, %s, %s, %s, %s, ...) = %s", t.Name, i.name, o[0], o[1], o[2], o[3], o[4], o[5], rval)
}
}