2015-05-01 03:49:14 +03:00
|
|
|
// Copyright 2015 Google Inc. All Rights Reserved.
|
|
|
|
//
|
|
|
|
// 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 fuseops
|
|
|
|
|
|
|
|
import (
|
2015-05-01 04:34:52 +03:00
|
|
|
"flag"
|
2015-05-01 04:43:46 +03:00
|
|
|
"fmt"
|
2015-05-01 04:55:13 +03:00
|
|
|
"log"
|
2015-05-01 03:57:49 +03:00
|
|
|
"reflect"
|
2015-05-01 04:24:05 +03:00
|
|
|
"strings"
|
2015-05-01 03:49:14 +03:00
|
|
|
"sync"
|
2015-05-01 04:49:25 +03:00
|
|
|
"time"
|
2015-05-01 03:49:14 +03:00
|
|
|
|
|
|
|
"github.com/jacobsa/bazilfuse"
|
2015-05-01 04:04:57 +03:00
|
|
|
"github.com/jacobsa/reqtrace"
|
2015-05-01 03:49:14 +03:00
|
|
|
"golang.org/x/net/context"
|
2015-05-01 04:49:25 +03:00
|
|
|
"golang.org/x/sys/unix"
|
2015-05-01 03:49:14 +03:00
|
|
|
)
|
|
|
|
|
2015-05-01 04:35:46 +03:00
|
|
|
var fTraceByPID = flag.Bool(
|
|
|
|
"fuse.trace_by_pid",
|
2015-05-01 04:34:52 +03:00
|
|
|
false,
|
|
|
|
"Enable a hacky mode that uses reqtrace to group all ops from each "+
|
|
|
|
"individual PID. Not a good idea to use in production; races, bugs, and "+
|
|
|
|
"resource leaks likely lurk.")
|
|
|
|
|
2015-05-05 03:20:03 +03:00
|
|
|
// An interface that all ops inside which commonOp is embedded must
|
|
|
|
// implement.
|
|
|
|
type internalOp interface {
|
|
|
|
Op
|
|
|
|
|
|
|
|
// Convert to a bazilfuse response compatible with the Respond method on the
|
|
|
|
// wrapped bazilfuse request. If that Respond method takes no arguments,
|
|
|
|
// return nil.
|
|
|
|
toBazilfuseResponse() interface{}
|
|
|
|
}
|
|
|
|
|
2015-05-01 03:49:14 +03:00
|
|
|
// A helper for embedding common behavior.
|
|
|
|
type commonOp struct {
|
2015-05-05 02:56:49 +03:00
|
|
|
// The context exposed to the user.
|
|
|
|
ctx context.Context
|
|
|
|
|
2015-05-05 02:48:16 +03:00
|
|
|
// The op in which this struct is embedded.
|
2015-05-05 03:21:21 +03:00
|
|
|
op internalOp
|
2015-05-01 05:21:06 +03:00
|
|
|
|
|
|
|
// The underlying bazilfuse request for this op.
|
2015-05-01 04:57:37 +03:00
|
|
|
bazilReq bazilfuse.Request
|
|
|
|
|
2015-05-05 02:52:25 +03:00
|
|
|
// A function that can be used to log information about the op. The first
|
|
|
|
// argument is a call depth.
|
|
|
|
log func(int, string, ...interface{})
|
2015-05-01 04:17:15 +03:00
|
|
|
|
2015-05-05 02:52:25 +03:00
|
|
|
// A function that is invoked with the error given to Respond, for use in
|
|
|
|
// closing off traces and reporting back to the connection.
|
2015-05-05 02:59:14 +03:00
|
|
|
finished func(error)
|
2015-05-01 03:49:14 +03:00
|
|
|
}
|
|
|
|
|
2015-05-01 04:43:46 +03:00
|
|
|
var gPIDMapMu sync.Mutex
|
|
|
|
|
|
|
|
// A map from PID to a traced context for that PID.
|
|
|
|
//
|
|
|
|
// GUARDED_BY(gPIDMapMu)
|
|
|
|
var gPIDMap = make(map[int]context.Context)
|
|
|
|
|
2015-05-01 04:49:25 +03:00
|
|
|
// Wait until the process completes, then close off the trace and remove the
|
|
|
|
// context from the map.
|
2015-05-01 04:43:46 +03:00
|
|
|
func reportWhenPIDGone(
|
|
|
|
pid int,
|
|
|
|
ctx context.Context,
|
2015-05-01 04:49:25 +03:00
|
|
|
report reqtrace.ReportFunc) {
|
2015-05-01 04:55:13 +03:00
|
|
|
// HACK(jacobsa): Poll until the process no longer exists.
|
2015-05-01 04:49:25 +03:00
|
|
|
const pollPeriod = 50 * time.Millisecond
|
|
|
|
for {
|
2015-05-01 04:55:13 +03:00
|
|
|
// The man page for kill(2) says that if the signal is zero, then "no
|
|
|
|
// signal is sent, but error checking is still performed; this can be used
|
|
|
|
// to check for the existence of a process ID".
|
2015-05-01 04:49:25 +03:00
|
|
|
err := unix.Kill(pid, 0)
|
2015-05-01 04:55:13 +03:00
|
|
|
|
|
|
|
// ESRCH means the process is gone.
|
2015-05-01 04:49:25 +03:00
|
|
|
if err == unix.ESRCH {
|
|
|
|
break
|
|
|
|
}
|
|
|
|
|
2015-05-01 04:55:13 +03:00
|
|
|
// If we receive EPERM, we're not going to be able to do what we want. We
|
|
|
|
// don't really have any choice but to print info and leak.
|
|
|
|
if err == unix.EPERM {
|
|
|
|
log.Printf("Failed to kill(2) PID %v; no permissions. Leaking trace.", pid)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Otherwise, panic.
|
2015-05-01 04:49:25 +03:00
|
|
|
if err != nil {
|
|
|
|
panic(fmt.Errorf("Kill(%v): %v", pid, err))
|
|
|
|
}
|
|
|
|
|
|
|
|
time.Sleep(pollPeriod)
|
|
|
|
}
|
|
|
|
|
|
|
|
// Finish up.
|
|
|
|
report(nil)
|
|
|
|
|
|
|
|
gPIDMapMu.Lock()
|
|
|
|
delete(gPIDMap, pid)
|
|
|
|
gPIDMapMu.Unlock()
|
|
|
|
}
|
2015-05-01 04:43:46 +03:00
|
|
|
|
|
|
|
func (o *commonOp) maybeTraceByPID(
|
|
|
|
in context.Context,
|
|
|
|
pid int) (out context.Context) {
|
2015-05-01 04:34:52 +03:00
|
|
|
// Is there anything to do?
|
2015-05-01 04:43:46 +03:00
|
|
|
if !reqtrace.Enabled() || !*fTraceByPID {
|
2015-05-01 04:34:52 +03:00
|
|
|
out = in
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
2015-05-01 04:43:46 +03:00
|
|
|
gPIDMapMu.Lock()
|
|
|
|
defer gPIDMapMu.Unlock()
|
|
|
|
|
|
|
|
// Do we already have a traced context for this PID?
|
|
|
|
if existing, ok := gPIDMap[pid]; ok {
|
|
|
|
out = existing
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Set up a new one and stick it in the map.
|
|
|
|
var report reqtrace.ReportFunc
|
2015-05-01 05:21:22 +03:00
|
|
|
out, report = reqtrace.Trace(in, fmt.Sprintf("Requests from PID %v", pid))
|
2015-05-01 04:43:46 +03:00
|
|
|
gPIDMap[pid] = out
|
|
|
|
|
|
|
|
// Ensure we close the trace and remove it from the map eventually.
|
|
|
|
go reportWhenPIDGone(pid, out, report)
|
|
|
|
|
2015-05-01 04:34:52 +03:00
|
|
|
return
|
|
|
|
}
|
|
|
|
|
2015-05-01 05:24:36 +03:00
|
|
|
func (o *commonOp) ShortDesc() (desc string) {
|
2015-05-01 05:28:25 +03:00
|
|
|
opName := reflect.TypeOf(o.op).String()
|
2015-05-01 05:24:36 +03:00
|
|
|
|
2015-05-01 05:28:25 +03:00
|
|
|
// Attempt to better handle the usual case: a string that looks like
|
|
|
|
// "*fuseops.GetInodeAttributesOp".
|
2015-05-01 05:24:36 +03:00
|
|
|
const prefix = "*fuseops."
|
|
|
|
const suffix = "Op"
|
2015-05-01 05:28:25 +03:00
|
|
|
if strings.HasPrefix(opName, prefix) && strings.HasSuffix(opName, suffix) {
|
|
|
|
opName = opName[len(prefix) : len(opName)-len(suffix)]
|
2015-05-01 05:24:36 +03:00
|
|
|
}
|
|
|
|
|
2015-05-01 05:28:25 +03:00
|
|
|
// Include the inode number to which the op applies.
|
|
|
|
desc = fmt.Sprintf("%s(inode=%v)", opName, o.bazilReq.Hdr().Node)
|
2015-05-01 05:24:36 +03:00
|
|
|
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
2015-05-01 03:49:14 +03:00
|
|
|
func (o *commonOp) init(
|
2015-05-01 04:17:15 +03:00
|
|
|
ctx context.Context,
|
2015-05-05 03:21:21 +03:00
|
|
|
op internalOp,
|
2015-05-01 04:57:37 +03:00
|
|
|
bazilReq bazilfuse.Request,
|
2015-05-01 03:49:14 +03:00
|
|
|
log func(int, string, ...interface{}),
|
2015-05-05 02:59:14 +03:00
|
|
|
finished func(error)) {
|
2015-05-01 04:04:57 +03:00
|
|
|
// Initialize basic fields.
|
2015-05-05 02:56:49 +03:00
|
|
|
o.ctx = ctx
|
2015-05-01 05:21:06 +03:00
|
|
|
o.op = op
|
2015-05-01 04:57:37 +03:00
|
|
|
o.bazilReq = bazilReq
|
2015-05-01 03:49:14 +03:00
|
|
|
o.log = log
|
2015-05-05 02:59:14 +03:00
|
|
|
o.finished = finished
|
2015-05-05 02:56:49 +03:00
|
|
|
|
|
|
|
// Set up a context that reflects per-PID tracing if appropriate.
|
|
|
|
o.ctx = o.maybeTraceByPID(o.ctx, int(bazilReq.Hdr().Pid))
|
2015-05-01 04:04:57 +03:00
|
|
|
|
|
|
|
// Set up a trace span for this op.
|
2015-05-05 02:56:49 +03:00
|
|
|
var reportForTrace reqtrace.ReportFunc
|
|
|
|
o.ctx, reportForTrace = reqtrace.StartSpan(ctx, o.op.ShortDesc())
|
|
|
|
|
|
|
|
// When the op is finished, report to both reqtrace and the connection.
|
2015-05-05 02:59:14 +03:00
|
|
|
prevFinish := o.finished
|
|
|
|
o.finished = func(err error) {
|
2015-05-05 02:56:49 +03:00
|
|
|
reportForTrace(err)
|
|
|
|
prevFinish(err)
|
|
|
|
}
|
2015-05-01 03:49:14 +03:00
|
|
|
}
|
|
|
|
|
|
|
|
func (o *commonOp) Header() OpHeader {
|
2015-05-01 04:57:37 +03:00
|
|
|
bh := o.bazilReq.Hdr()
|
2015-05-01 03:49:14 +03:00
|
|
|
return OpHeader{
|
|
|
|
Uid: bh.Uid,
|
|
|
|
Gid: bh.Gid,
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
func (o *commonOp) Context() context.Context {
|
|
|
|
return o.ctx
|
|
|
|
}
|
|
|
|
|
|
|
|
func (o *commonOp) Logf(format string, v ...interface{}) {
|
|
|
|
const calldepth = 2
|
|
|
|
o.log(calldepth, format, v...)
|
|
|
|
}
|
|
|
|
|
2015-05-05 03:25:25 +03:00
|
|
|
func (o *commonOp) Respond(err error) {
|
2015-05-05 03:07:34 +03:00
|
|
|
// Don't forget to report back to the connection that we are finished.
|
|
|
|
defer o.finished(err)
|
|
|
|
|
2015-05-05 03:25:25 +03:00
|
|
|
// If successful, we should respond to bazilfuse with the appropriate struct.
|
|
|
|
if err == nil {
|
|
|
|
o.sendBazilfuseResponse(o.op.toBazilfuseResponse())
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Log the error.
|
2015-05-01 03:49:14 +03:00
|
|
|
o.Logf(
|
|
|
|
"-> (%s) error: %v",
|
2015-05-01 05:38:03 +03:00
|
|
|
o.op.ShortDesc(),
|
2015-05-01 03:49:14 +03:00
|
|
|
err)
|
|
|
|
|
2015-05-05 02:57:41 +03:00
|
|
|
// Send a response to the kernel.
|
2015-05-01 04:57:37 +03:00
|
|
|
o.bazilReq.RespondError(err)
|
2015-05-01 03:49:14 +03:00
|
|
|
}
|
2015-05-01 03:57:49 +03:00
|
|
|
|
|
|
|
// Respond with the supplied response struct, which must be accepted by a
|
2015-05-01 04:57:37 +03:00
|
|
|
// method called Respond on o.bazilReq.
|
2015-05-01 03:57:49 +03:00
|
|
|
//
|
2015-05-01 04:57:37 +03:00
|
|
|
// Special case: nil means o.bazilReq.Respond accepts no parameters.
|
2015-05-05 03:25:25 +03:00
|
|
|
func (o *commonOp) sendBazilfuseResponse(resp interface{}) {
|
2015-05-01 03:57:49 +03:00
|
|
|
// Find the Respond method.
|
2015-05-01 04:57:37 +03:00
|
|
|
v := reflect.ValueOf(o.bazilReq)
|
2015-05-01 03:57:49 +03:00
|
|
|
respond := v.MethodByName("Respond")
|
|
|
|
|
|
|
|
// Special case: handle successful ops with no response struct.
|
|
|
|
if resp == nil {
|
2015-05-01 05:38:03 +03:00
|
|
|
o.Logf("-> (%s) OK", o.op.ShortDesc())
|
2015-05-01 03:57:49 +03:00
|
|
|
respond.Call([]reflect.Value{})
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
2015-05-05 02:58:18 +03:00
|
|
|
// Otherwise, send the response struct to the kernel.
|
2015-05-01 03:57:49 +03:00
|
|
|
o.Logf("-> %v", resp)
|
|
|
|
respond.Call([]reflect.Value{reflect.ValueOf(resp)})
|
|
|
|
}
|