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// Copyright 2019 The SwiftShader Authors. 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 shell provides functions for running sub-processes.
package shell
import (
"bytes"
"fmt"
"log"
"os"
"os/exec"
"os/signal"
"strconv"
"syscall"
"time"
"../cause"
)
// MaxProcMemory is the maximum virtual memory per child process
var MaxProcMemory uint64 = 2 * 1024 * 1024 * 1024 // 2GB
func init() {
// As we are going to be running a number of tests concurrently, we need to
// limit the amount of virtual memory each test uses, otherwise memory
// hungry tests can bring the whole system down into a swapping apocalypse.
//
// Linux has the setrlimit() function to limit a process (and child's)
// virtual memory usage - but we cannot call this from the regres process
// as this process may need more memory than the limit allows.
//
// Unfortunately golang has no native support for setting rlimits for child
// processes (https://github.com/golang/go/issues/6603), so we instead wrap
// the exec to the test executable with another child regres process using a
// special --exec mode:
//
// [regres] -> [regres --exec <test-exe N args...>] -> [test-exe]
// ^^^^
// (calls rlimit() with memory limit of N bytes)
if len(os.Args) > 3 && os.Args[1] == "--exec" {
exe := os.Args[2]
limit, err := strconv.ParseUint(os.Args[3], 10, 64)
if err != nil {
log.Fatalf("Expected memory limit as 3rd argument. %v\n", err)
}
if limit > 0 {
if err := syscall.Setrlimit(syscall.RLIMIT_AS, &syscall.Rlimit{Cur: limit, Max: limit}); err != nil {
log.Fatalln(cause.Wrap(err, "Setrlimit").Error())
}
}
cmd := exec.Command(exe, os.Args[4:]...)
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Start(); err != nil {
os.Stderr.WriteString(err.Error())
os.Exit(1)
}
// Forward signals to the child process
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
go func() {
for sig := range c {
cmd.Process.Signal(sig)
}
}()
cmd.Wait()
close(c)
os.Exit(cmd.ProcessState.ExitCode())
}
}
// Shell runs the executable exe with the given arguments, in the working
// directory wd.
// If the process does not finish within timeout a errTimeout will be returned.
func Shell(timeout time.Duration, exe, wd string, args ...string) error {
if out, err := Exec(timeout, exe, wd, nil, args...); err != nil {
return cause.Wrap(err, "%s", out)
}
return nil
}
// Exec runs the executable exe with the given arguments, in the working
// directory wd, with the custom environment flags.
// If the process does not finish within timeout a errTimeout will be returned.
func Exec(timeout time.Duration, exe, wd string, env []string, args ...string) ([]byte, error) {
// Shell via regres: --exec N <exe> <args...>
// See main() for details.
args = append([]string{"--exec", exe, fmt.Sprintf("%v", MaxProcMemory)}, args...)
b := bytes.Buffer{}
c := exec.Command(os.Args[0], args...)
c.Dir = wd
c.Env = env
c.Stdout = &b
c.Stderr = &b
if err := c.Start(); err != nil {
return nil, err
}
res := make(chan error)
go func() { res <- c.Wait() }()
select {
case <-time.NewTimer(timeout).C:
log.Printf("Timeout for process %v\n", c.Process.Pid)
c.Process.Signal(syscall.SIGINT)
time.Sleep(time.Second * 5)
if !c.ProcessState.Exited() {
log.Printf("Process %v still has not exited, killing\n", c.Process.Pid)
syscall.Kill(-c.Process.Pid, syscall.SIGKILL)
}
return b.Bytes(), ErrTimeout{exe, timeout}
case err := <-res:
return b.Bytes(), err
}
}
// ErrTimeout is the error returned when a process does not finish with its
// permitted time.
type ErrTimeout struct {
process string
timeout time.Duration
}
func (e ErrTimeout) Error() string {
return fmt.Sprintf("'%v' did not return after %v", e.process, e.timeout)
}