From ccd992355df7192993c666236047820244914598 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:19:13 +0200 Subject: Adding upstream version 1.21.8. Signed-off-by: Daniel Baumann --- src/os/timeout_test.go | 708 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 708 insertions(+) create mode 100644 src/os/timeout_test.go (limited to 'src/os/timeout_test.go') diff --git a/src/os/timeout_test.go b/src/os/timeout_test.go new file mode 100644 index 0000000..e0d2328 --- /dev/null +++ b/src/os/timeout_test.go @@ -0,0 +1,708 @@ +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:build !js && !plan9 && !wasip1 && !windows + +package os_test + +import ( + "fmt" + "io" + "math/rand" + "os" + "os/signal" + "runtime" + "sync" + "syscall" + "testing" + "time" +) + +func TestNonpollableDeadline(t *testing.T) { + // On BSD systems regular files seem to be pollable, + // so just run this test on Linux. + if runtime.GOOS != "linux" { + t.Skipf("skipping on %s", runtime.GOOS) + } + t.Parallel() + + f, err := os.CreateTemp("", "ostest") + if err != nil { + t.Fatal(err) + } + defer os.Remove(f.Name()) + defer f.Close() + deadline := time.Now().Add(10 * time.Second) + if err := f.SetDeadline(deadline); err != os.ErrNoDeadline { + t.Errorf("SetDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline) + } + if err := f.SetReadDeadline(deadline); err != os.ErrNoDeadline { + t.Errorf("SetReadDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline) + } + if err := f.SetWriteDeadline(deadline); err != os.ErrNoDeadline { + t.Errorf("SetWriteDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline) + } +} + +// noDeadline is a zero time.Time value, which cancels a deadline. +var noDeadline time.Time + +var readTimeoutTests = []struct { + timeout time.Duration + xerrs [2]error // expected errors in transition +}{ + // Tests that read deadlines work, even if there's data ready + // to be read. + {-5 * time.Second, [2]error{os.ErrDeadlineExceeded, os.ErrDeadlineExceeded}}, + + {50 * time.Millisecond, [2]error{nil, os.ErrDeadlineExceeded}}, +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestReadTimeout(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + if _, err := w.Write([]byte("READ TIMEOUT TEST")); err != nil { + t.Fatal(err) + } + + for i, tt := range readTimeoutTests { + if err := r.SetReadDeadline(time.Now().Add(tt.timeout)); err != nil { + t.Fatalf("#%d: %v", i, err) + } + var b [1]byte + for j, xerr := range tt.xerrs { + for { + n, err := r.Read(b[:]) + if xerr != nil { + if !isDeadlineExceeded(err) { + t.Fatalf("#%d/%d: %v", i, j, err) + } + } + if err == nil { + time.Sleep(tt.timeout / 3) + continue + } + if n != 0 { + t.Fatalf("#%d/%d: read %d; want 0", i, j, n) + } + break + } + } + } +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestReadTimeoutMustNotReturn(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + max := time.NewTimer(100 * time.Millisecond) + defer max.Stop() + ch := make(chan error) + go func() { + if err := r.SetDeadline(time.Now().Add(-5 * time.Second)); err != nil { + t.Error(err) + } + if err := r.SetWriteDeadline(time.Now().Add(-5 * time.Second)); err != nil { + t.Error(err) + } + if err := r.SetReadDeadline(noDeadline); err != nil { + t.Error(err) + } + var b [1]byte + _, err := r.Read(b[:]) + ch <- err + }() + + select { + case err := <-ch: + t.Fatalf("expected Read to not return, but it returned with %v", err) + case <-max.C: + w.Close() + err := <-ch // wait for tester goroutine to stop + if os.IsTimeout(err) { + t.Fatal(err) + } + } +} + +var writeTimeoutTests = []struct { + timeout time.Duration + xerrs [2]error // expected errors in transition +}{ + // Tests that write deadlines work, even if there's buffer + // space available to write. + {-5 * time.Second, [2]error{os.ErrDeadlineExceeded, os.ErrDeadlineExceeded}}, + + {10 * time.Millisecond, [2]error{nil, os.ErrDeadlineExceeded}}, +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestWriteTimeout(t *testing.T) { + t.Parallel() + + for i, tt := range writeTimeoutTests { + t.Run(fmt.Sprintf("#%d", i), func(t *testing.T) { + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + if err := w.SetWriteDeadline(time.Now().Add(tt.timeout)); err != nil { + t.Fatalf("%v", err) + } + for j, xerr := range tt.xerrs { + for { + n, err := w.Write([]byte("WRITE TIMEOUT TEST")) + if xerr != nil { + if !isDeadlineExceeded(err) { + t.Fatalf("%d: %v", j, err) + } + } + if err == nil { + time.Sleep(tt.timeout / 3) + continue + } + if n != 0 { + t.Fatalf("%d: wrote %d; want 0", j, n) + } + break + } + } + }) + } +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestWriteTimeoutMustNotReturn(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + max := time.NewTimer(100 * time.Millisecond) + defer max.Stop() + ch := make(chan error) + go func() { + if err := w.SetDeadline(time.Now().Add(-5 * time.Second)); err != nil { + t.Error(err) + } + if err := w.SetReadDeadline(time.Now().Add(-5 * time.Second)); err != nil { + t.Error(err) + } + if err := w.SetWriteDeadline(noDeadline); err != nil { + t.Error(err) + } + var b [1]byte + for { + if _, err := w.Write(b[:]); err != nil { + ch <- err + break + } + } + }() + + select { + case err := <-ch: + t.Fatalf("expected Write to not return, but it returned with %v", err) + case <-max.C: + r.Close() + err := <-ch // wait for tester goroutine to stop + if os.IsTimeout(err) { + t.Fatal(err) + } + } +} + +const ( + // minDynamicTimeout is the minimum timeout to attempt for + // tests that automatically increase timeouts until success. + // + // Lower values may allow tests to succeed more quickly if the value is close + // to the true minimum, but may require more iterations (and waste more time + // and CPU power on failed attempts) if the timeout is too low. + minDynamicTimeout = 1 * time.Millisecond + + // maxDynamicTimeout is the maximum timeout to attempt for + // tests that automatically increase timeouts until success. + // + // This should be a strict upper bound on the latency required to hit a + // timeout accurately, even on a slow or heavily-loaded machine. If a test + // would increase the timeout beyond this value, the test fails. + maxDynamicTimeout = 4 * time.Second +) + +// timeoutUpperBound returns the maximum time that we expect a timeout of +// duration d to take to return the caller. +func timeoutUpperBound(d time.Duration) time.Duration { + switch runtime.GOOS { + case "openbsd", "netbsd": + // NetBSD and OpenBSD seem to be unable to reliably hit deadlines even when + // the absolute durations are long. + // In https://build.golang.org/log/c34f8685d020b98377dd4988cd38f0c5bd72267e, + // we observed that an openbsd-amd64-68 builder took 4.090948779s for a + // 2.983020682s timeout (37.1% overhead). + // (See https://go.dev/issue/50189 for further detail.) + // Give them lots of slop to compensate. + return d * 3 / 2 + } + // Other platforms seem to hit their deadlines more reliably, + // at least when they are long enough to cover scheduling jitter. + return d * 11 / 10 +} + +// nextTimeout returns the next timeout to try after an operation took the given +// actual duration with a timeout shorter than that duration. +func nextTimeout(actual time.Duration) (next time.Duration, ok bool) { + if actual >= maxDynamicTimeout { + return maxDynamicTimeout, false + } + // Since the previous attempt took actual, we can't expect to beat that + // duration by any significant margin. Try the next attempt with an arbitrary + // factor above that, so that our growth curve is at least exponential. + next = actual * 5 / 4 + if next > maxDynamicTimeout { + return maxDynamicTimeout, true + } + return next, true +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestReadTimeoutFluctuation(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + d := minDynamicTimeout + b := make([]byte, 256) + for { + t.Logf("SetReadDeadline(+%v)", d) + t0 := time.Now() + deadline := t0.Add(d) + if err = r.SetReadDeadline(deadline); err != nil { + t.Fatalf("SetReadDeadline(%v): %v", deadline, err) + } + var n int + n, err = r.Read(b) + t1 := time.Now() + + if n != 0 || err == nil || !isDeadlineExceeded(err) { + t.Errorf("Read did not return (0, timeout): (%d, %v)", n, err) + } + + actual := t1.Sub(t0) + if t1.Before(deadline) { + t.Errorf("Read took %s; expected at least %s", actual, d) + } + if t.Failed() { + return + } + if want := timeoutUpperBound(d); actual > want { + next, ok := nextTimeout(actual) + if !ok { + t.Fatalf("Read took %s; expected at most %v", actual, want) + } + // Maybe this machine is too slow to reliably schedule goroutines within + // the requested duration. Increase the timeout and try again. + t.Logf("Read took %s (expected %s); trying with longer timeout", actual, d) + d = next + continue + } + + break + } +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestWriteTimeoutFluctuation(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + d := minDynamicTimeout + for { + t.Logf("SetWriteDeadline(+%v)", d) + t0 := time.Now() + deadline := t0.Add(d) + if err := w.SetWriteDeadline(deadline); err != nil { + t.Fatalf("SetWriteDeadline(%v): %v", deadline, err) + } + var n int64 + var err error + for { + var dn int + dn, err = w.Write([]byte("TIMEOUT TRANSMITTER")) + n += int64(dn) + if err != nil { + break + } + } + t1 := time.Now() + // Inv: err != nil + if !isDeadlineExceeded(err) { + t.Fatalf("Write did not return (any, timeout): (%d, %v)", n, err) + } + + actual := t1.Sub(t0) + if t1.Before(deadline) { + t.Errorf("Write took %s; expected at least %s", actual, d) + } + if t.Failed() { + return + } + if want := timeoutUpperBound(d); actual > want { + if n > 0 { + // SetWriteDeadline specifies a time “after which I/O operations fail + // instead of blocking”. However, the kernel's send buffer is not yet + // full, we may be able to write some arbitrary (but finite) number of + // bytes to it without blocking. + t.Logf("Wrote %d bytes into send buffer; retrying until buffer is full", n) + if d <= maxDynamicTimeout/2 { + // We don't know how long the actual write loop would have taken if + // the buffer were full, so just guess and double the duration so that + // the next attempt can make twice as much progress toward filling it. + d *= 2 + } + } else if next, ok := nextTimeout(actual); !ok { + t.Fatalf("Write took %s; expected at most %s", actual, want) + } else { + // Maybe this machine is too slow to reliably schedule goroutines within + // the requested duration. Increase the timeout and try again. + t.Logf("Write took %s (expected %s); trying with longer timeout", actual, d) + d = next + } + continue + } + + break + } +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestVariousDeadlines(t *testing.T) { + t.Parallel() + testVariousDeadlines(t) +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestVariousDeadlines1Proc(t *testing.T) { + // Cannot use t.Parallel - modifies global GOMAXPROCS. + if testing.Short() { + t.Skip("skipping in short mode") + } + defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1)) + testVariousDeadlines(t) +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestVariousDeadlines4Proc(t *testing.T) { + // Cannot use t.Parallel - modifies global GOMAXPROCS. + if testing.Short() { + t.Skip("skipping in short mode") + } + defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4)) + testVariousDeadlines(t) +} + +type neverEnding byte + +func (b neverEnding) Read(p []byte) (int, error) { + for i := range p { + p[i] = byte(b) + } + return len(p), nil +} + +func testVariousDeadlines(t *testing.T) { + type result struct { + n int64 + err error + d time.Duration + } + + handler := func(w *os.File, pasvch chan result) { + // The writer, with no timeouts of its own, + // sending bytes to clients as fast as it can. + t0 := time.Now() + n, err := io.Copy(w, neverEnding('a')) + dt := time.Since(t0) + pasvch <- result{n, err, dt} + } + + for _, timeout := range []time.Duration{ + 1 * time.Nanosecond, + 2 * time.Nanosecond, + 5 * time.Nanosecond, + 50 * time.Nanosecond, + 100 * time.Nanosecond, + 200 * time.Nanosecond, + 500 * time.Nanosecond, + 750 * time.Nanosecond, + 1 * time.Microsecond, + 5 * time.Microsecond, + 25 * time.Microsecond, + 250 * time.Microsecond, + 500 * time.Microsecond, + 1 * time.Millisecond, + 5 * time.Millisecond, + 100 * time.Millisecond, + 250 * time.Millisecond, + 500 * time.Millisecond, + 1 * time.Second, + } { + numRuns := 3 + if testing.Short() { + numRuns = 1 + if timeout > 500*time.Microsecond { + continue + } + } + for run := 0; run < numRuns; run++ { + t.Run(fmt.Sprintf("%v-%d", timeout, run+1), func(t *testing.T) { + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + pasvch := make(chan result) + go handler(w, pasvch) + + tooLong := 5 * time.Second + max := time.NewTimer(tooLong) + defer max.Stop() + actvch := make(chan result) + go func() { + t0 := time.Now() + if err := r.SetDeadline(t0.Add(timeout)); err != nil { + t.Error(err) + } + n, err := io.Copy(io.Discard, r) + dt := time.Since(t0) + r.Close() + actvch <- result{n, err, dt} + }() + + select { + case res := <-actvch: + if !isDeadlineExceeded(err) { + t.Logf("good client timeout after %v, reading %d bytes", res.d, res.n) + } else { + t.Fatalf("client Copy = %d, %v; want timeout", res.n, res.err) + } + case <-max.C: + t.Fatalf("timeout (%v) waiting for client to timeout (%v) reading", tooLong, timeout) + } + + select { + case res := <-pasvch: + t.Logf("writer in %v wrote %d: %v", res.d, res.n, res.err) + case <-max.C: + t.Fatalf("timeout waiting for writer to finish writing") + } + }) + } + } +} + +// There is a very similar copy of this in net/timeout_test.go. +func TestReadWriteDeadlineRace(t *testing.T) { + t.Parallel() + + N := 1000 + if testing.Short() { + N = 50 + } + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + var wg sync.WaitGroup + wg.Add(3) + go func() { + defer wg.Done() + tic := time.NewTicker(2 * time.Microsecond) + defer tic.Stop() + for i := 0; i < N; i++ { + if err := r.SetReadDeadline(time.Now().Add(2 * time.Microsecond)); err != nil { + break + } + if err := w.SetWriteDeadline(time.Now().Add(2 * time.Microsecond)); err != nil { + break + } + <-tic.C + } + }() + go func() { + defer wg.Done() + var b [1]byte + for i := 0; i < N; i++ { + _, err := r.Read(b[:]) + if err != nil && !isDeadlineExceeded(err) { + t.Error("Read returned non-timeout error", err) + } + } + }() + go func() { + defer wg.Done() + var b [1]byte + for i := 0; i < N; i++ { + _, err := w.Write(b[:]) + if err != nil && !isDeadlineExceeded(err) { + t.Error("Write returned non-timeout error", err) + } + } + }() + wg.Wait() // wait for tester goroutine to stop +} + +// TestRacyRead tests that it is safe to mutate the input Read buffer +// immediately after cancellation has occurred. +func TestRacyRead(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + var wg sync.WaitGroup + defer wg.Wait() + + go io.Copy(w, rand.New(rand.NewSource(0))) + + r.SetReadDeadline(time.Now().Add(time.Millisecond)) + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + + b1 := make([]byte, 1024) + b2 := make([]byte, 1024) + for j := 0; j < 100; j++ { + _, err := r.Read(b1) + copy(b1, b2) // Mutate b1 to trigger potential race + if err != nil { + if !isDeadlineExceeded(err) { + t.Error(err) + } + r.SetReadDeadline(time.Now().Add(time.Millisecond)) + } + } + }() + } +} + +// TestRacyWrite tests that it is safe to mutate the input Write buffer +// immediately after cancellation has occurred. +func TestRacyWrite(t *testing.T) { + t.Parallel() + + r, w, err := os.Pipe() + if err != nil { + t.Fatal(err) + } + defer r.Close() + defer w.Close() + + var wg sync.WaitGroup + defer wg.Wait() + + go io.Copy(io.Discard, r) + + w.SetWriteDeadline(time.Now().Add(time.Millisecond)) + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + + b1 := make([]byte, 1024) + b2 := make([]byte, 1024) + for j := 0; j < 100; j++ { + _, err := w.Write(b1) + copy(b1, b2) // Mutate b1 to trigger potential race + if err != nil { + if !isDeadlineExceeded(err) { + t.Error(err) + } + w.SetWriteDeadline(time.Now().Add(time.Millisecond)) + } + } + }() + } +} + +// Closing a TTY while reading from it should not hang. Issue 23943. +func TestTTYClose(t *testing.T) { + // Ignore SIGTTIN in case we are running in the background. + signal.Ignore(syscall.SIGTTIN) + defer signal.Reset(syscall.SIGTTIN) + + f, err := os.Open("/dev/tty") + if err != nil { + t.Skipf("skipping because opening /dev/tty failed: %v", err) + } + + go func() { + var buf [1]byte + f.Read(buf[:]) + }() + + // Give the goroutine a chance to enter the read. + // It doesn't matter much if it occasionally fails to do so, + // we won't be testing what we want to test but the test will pass. + time.Sleep(time.Millisecond) + + c := make(chan bool) + go func() { + defer close(c) + f.Close() + }() + + select { + case <-c: + case <-time.After(time.Second): + t.Error("timed out waiting for close") + } + + // On some systems the goroutines may now be hanging. + // There's not much we can do about that. +} -- cgit v1.2.3