go-sandbox/daemon/master_cmd_execve.go
2020-02-12 03:01:37 -05:00

162 lines
3.7 KiB
Go

package daemon
import (
"context"
"fmt"
"time"
"github.com/criyle/go-sandbox/pkg/rlimit"
"github.com/criyle/go-sandbox/pkg/unixsocket"
"github.com/criyle/go-sandbox/types"
)
// ExecveParam is parameters to run process inside container
type ExecveParam struct {
Args []string
Env []string
Fds []uintptr
// fexecve fd
ExecFile uintptr
// POSIX Resource limit set by set rlimit
RLimits []rlimit.RLimit
// SyncFunc called with pid before execve (e.g. add to cgroup)
SyncFunc func(pid int) error
}
// Execve runs process inside container
// accepts context for cancelation
func (m *Master) Execve(c context.Context, param *ExecveParam) <-chan types.Result {
m.mu.Lock()
sTime := time.Now()
// make sure goroutine not leaked (blocked) even if result is not consumed
result := make(chan types.Result, 1)
errResult := func(f string, v ...interface{}) <-chan types.Result {
result <- types.Result{
Status: types.StatusRunnerError,
Error: fmt.Sprintf(f, v...),
}
return result
}
// if execve with fd, put fd at the first parameter
var files []int
if param.ExecFile > 0 {
files = append(files, int(param.ExecFile))
}
files = append(files, uintptrSliceToInt(param.Fds)...)
msg := &unixsocket.Msg{
Fds: files,
}
execCmd := &ExecCmd{
Argv: param.Args,
Env: param.Env,
RLimits: param.RLimits,
FdExec: param.ExecFile > 0,
}
cmd := Cmd{
Cmd: cmdExecve,
ExecCmd: execCmd,
}
if err := m.sendCmd(&cmd, msg); err != nil {
m.mu.Unlock()
return errResult("execve: sendCmd %v", err)
}
// sync function
reply, msg, err := m.recvReply()
if err != nil {
m.mu.Unlock()
return errResult("execve: recvReply %v", err)
}
// if sync function did not involved
if reply.Error != nil || msg == nil || msg.Cred == nil {
// tell kill function to exit and sync
m.execveSyncKill()
m.mu.Unlock()
return errResult("execve: no pid received or error %v", reply.Error)
}
if param.SyncFunc != nil {
if err := param.SyncFunc(int(msg.Cred.Pid)); err != nil {
// tell sync function to exit and recv error
m.execveSyncKill()
// tell kill function to exit and sync
m.execveSyncKill()
m.mu.Unlock()
return errResult("execve: syncfunc failed %v", err)
}
}
// send to syncFunc ack ok
if err := m.sendCmd(&Cmd{Cmd: cmdOk}, nil); err != nil {
m.mu.Unlock()
return errResult("execve: ack failed %v", err)
}
mTime := time.Now()
waitDone := make(chan struct{})
// Wait
go func() {
reply2, _, err := m.recvReply()
close(waitDone)
// done signal (should recv after kill)
m.recvReply()
// unlock after last read / write
m.mu.Unlock()
// handle potential error
if err != nil {
result <- types.Result{
Status: types.StatusRunnerError,
Error: err.Error(),
}
return
}
if reply2.Error != nil {
result <- types.Result{
Status: types.StatusRunnerError,
Error: reply2.Error.Error(),
}
return
}
if reply2.ExecReply == nil {
result <- types.Result{
Status: types.StatusRunnerError,
Error: "execve: no reply received",
}
return
}
// emit result after all communication finish
result <- types.Result{
Status: reply2.ExecReply.Status,
ExitStatus: reply2.ExecReply.ExitStatus,
Time: reply2.ExecReply.Time,
Memory: reply2.ExecReply.Memory,
SetUpTime: mTime.Sub(sTime),
RunningTime: time.Since(mTime),
}
}()
// Kill (if wait is done, a kill message need to be send to collect zombies)
go func() {
select {
case <-c.Done():
case <-waitDone:
}
m.sendCmd(&Cmd{Cmd: cmdKill}, nil)
}()
return result
}
// execveSyncKill will send kill and recv reply
func (m *Master) execveSyncKill() {
m.sendCmd(&Cmd{Cmd: cmdKill}, nil)
m.recvReply()
}