Ben Clayton | a2a00e2 | 2019-02-16 01:05:23 +0000 | [diff] [blame^] | 1 | // Copyright 2019 The SwiftShader Authors. All Rights Reserved. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | // Package shell provides functions for running sub-processes. |
| 16 | package shell |
| 17 | |
| 18 | import ( |
| 19 | "bytes" |
| 20 | "fmt" |
| 21 | "log" |
| 22 | "os" |
| 23 | "os/exec" |
| 24 | "strconv" |
| 25 | "syscall" |
| 26 | "time" |
| 27 | |
| 28 | "../cause" |
| 29 | ) |
| 30 | |
| 31 | // MaxProcMemory is the maximum virtual memory per child process |
| 32 | var MaxProcMemory uint64 = 2 * 1024 * 1024 * 1024 // 2GB |
| 33 | |
| 34 | func init() { |
| 35 | // As we are going to be running a number of tests concurrently, we need to |
| 36 | // limit the amount of virtual memory each test uses, otherwise memory |
| 37 | // hungry tests can bring the whole system down into a swapping apocalypse. |
| 38 | // |
| 39 | // Linux has the setrlimit() function to limit a process (and child's) |
| 40 | // virtual memory usage - but we cannot call this from the regres process |
| 41 | // as this process may need more memory than the limit allows. |
| 42 | // |
| 43 | // Unfortunately golang has no native support for setting rlimits for child |
| 44 | // processes (https://github.com/golang/go/issues/6603), so we instead wrap |
| 45 | // the exec to the test executable with another child regres process using a |
| 46 | // special --exec mode: |
| 47 | // |
| 48 | // [regres] -> [regres --exec <test-exe N args...>] -> [test-exe] |
| 49 | // ^^^^ |
| 50 | // (calls rlimit() with memory limit of N bytes) |
| 51 | |
| 52 | if len(os.Args) > 3 && os.Args[1] == "--exec" { |
| 53 | exe := os.Args[2] |
| 54 | limit, err := strconv.ParseUint(os.Args[3], 10, 64) |
| 55 | if err != nil { |
| 56 | log.Fatalf("Expected memory limit as 3rd argument. %v\n", err) |
| 57 | } |
| 58 | if limit > 0 { |
| 59 | if err := syscall.Setrlimit(syscall.RLIMIT_AS, &syscall.Rlimit{Cur: limit, Max: limit}); err != nil { |
| 60 | log.Fatalln(cause.Wrap(err, "Setrlimit").Error()) |
| 61 | } |
| 62 | } |
| 63 | c := exec.Command(exe, os.Args[4:]...) |
| 64 | c.Stdin = os.Stdin |
| 65 | c.Stdout = os.Stdout |
| 66 | c.Stderr = os.Stderr |
| 67 | c.Run() |
| 68 | os.Exit(c.ProcessState.ExitCode()) |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | // Shell runs the executable exe with the given arguments, in the working |
| 73 | // directory wd. |
| 74 | // If the process does not finish within timeout a errTimeout will be returned. |
| 75 | func Shell(timeout time.Duration, exe, wd string, args ...string) error { |
| 76 | if out, err := Exec(timeout, exe, wd, nil, args...); err != nil { |
| 77 | return cause.Wrap(err, "%s", out) |
| 78 | } |
| 79 | return nil |
| 80 | } |
| 81 | |
| 82 | // Exec runs the executable exe with the given arguments, in the working |
| 83 | // directory wd, with the custom environment flags. |
| 84 | // If the process does not finish within timeout a errTimeout will be returned. |
| 85 | func Exec(timeout time.Duration, exe, wd string, env []string, args ...string) ([]byte, error) { |
| 86 | // Shell via regres: --exec N <exe> <args...> |
| 87 | // See main() for details. |
| 88 | args = append([]string{"--exec", exe, fmt.Sprintf("%v", MaxProcMemory)}, args...) |
| 89 | b := bytes.Buffer{} |
| 90 | c := exec.Command(os.Args[0], args...) |
| 91 | c.Dir = wd |
| 92 | c.Env = env |
| 93 | c.Stdout = &b |
| 94 | c.Stderr = &b |
| 95 | |
| 96 | if err := c.Start(); err != nil { |
| 97 | return nil, err |
| 98 | } |
| 99 | |
| 100 | res := make(chan error) |
| 101 | go func() { res <- c.Wait() }() |
| 102 | |
| 103 | select { |
| 104 | case <-time.NewTimer(timeout).C: |
| 105 | c.Process.Signal(syscall.SIGINT) |
| 106 | time.Sleep(time.Second * 5) |
| 107 | if !c.ProcessState.Exited() { |
| 108 | c.Process.Kill() |
| 109 | } |
| 110 | return b.Bytes(), ErrTimeout{exe, timeout} |
| 111 | case err := <-res: |
| 112 | return b.Bytes(), err |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | // ErrTimeout is the error returned when a process does not finish with its |
| 117 | // permitted time. |
| 118 | type ErrTimeout struct { |
| 119 | process string |
| 120 | timeout time.Duration |
| 121 | } |
| 122 | |
| 123 | func (e ErrTimeout) Error() string { |
| 124 | return fmt.Sprintf("'%v' did not return after %v", e.process, e.timeout) |
| 125 | } |