From ce58d71fd526587c0ed5e898e3a680c30c02c6d2 Mon Sep 17 00:00:00 2001 From: Zach Koopmans Date: Fri, 13 Aug 2021 17:14:36 -0700 Subject: [syserror] Remove pkg syserror. Removes package syserror and moves still relevant code to either linuxerr or to syserr (to be later removed). Internal errors are converted from random types to *errors.Error types used in linuxerr. Internal errors are in linuxerr/internal.go. PiperOrigin-RevId: 390724202 --- pkg/errors/linuxerr/BUILD | 2 +- pkg/errors/linuxerr/internal.go | 120 +++++++++++++++++++++++++++++++++++ pkg/errors/linuxerr/linuxerr_test.go | 90 ++++++++------------------ 3 files changed, 147 insertions(+), 65 deletions(-) create mode 100644 pkg/errors/linuxerr/internal.go (limited to 'pkg/errors/linuxerr') diff --git a/pkg/errors/linuxerr/BUILD b/pkg/errors/linuxerr/BUILD index f99544afd..e73b0e28a 100644 --- a/pkg/errors/linuxerr/BUILD +++ b/pkg/errors/linuxerr/BUILD @@ -5,6 +5,7 @@ package(licenses = ["notice"]) go_library( name = "linuxerr", srcs = [ + "internal.go", "linuxerr.go", ], visibility = ["//visibility:public"], @@ -22,7 +23,6 @@ go_test( ":linuxerr", "//pkg/abi/linux/errno", "//pkg/errors", - "//pkg/syserror", "@org_golang_x_sys//unix:go_default_library", ], ) diff --git a/pkg/errors/linuxerr/internal.go b/pkg/errors/linuxerr/internal.go new file mode 100644 index 000000000..127bba0df --- /dev/null +++ b/pkg/errors/linuxerr/internal.go @@ -0,0 +1,120 @@ +// Copyright 2021 The gVisor Authors. +// +// 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 linuxerr + +import ( + "gvisor.dev/gvisor/pkg/abi/linux/errno" + "gvisor.dev/gvisor/pkg/errors" +) + +var ( + // ErrWouldBlock is an internal error used to indicate that an operation + // cannot be satisfied immediately, and should be retried at a later + // time, possibly when the caller has received a notification that the + // operation may be able to complete. It is used by implementations of + // the kio.File interface. + ErrWouldBlock = errors.New(errno.EWOULDBLOCK, "request would block") + + // ErrInterrupted is returned if a request is interrupted before it can + // complete. + ErrInterrupted = errors.New(errno.EINTR, "request was interrupted") + + // ErrExceedsFileSizeLimit is returned if a request would exceed the + // file's size limit. + ErrExceedsFileSizeLimit = errors.New(errno.E2BIG, "exceeds file size limit") +) + +var errorMap = map[error]*errors.Error{ + ErrWouldBlock: EWOULDBLOCK, + ErrInterrupted: EINTR, + ErrExceedsFileSizeLimit: EFBIG, +} + +// errorUnwrappers is an array of unwrap functions to extract typed errors. +var errorUnwrappers = []func(error) (*errors.Error, bool){} + +// AddErrorUnwrapper registers an unwrap method that can extract a concrete error +// from a typed, but not initialized, error. +func AddErrorUnwrapper(unwrap func(e error) (*errors.Error, bool)) { + errorUnwrappers = append(errorUnwrappers, unwrap) +} + +// TranslateError translates errors to errnos, it will return false if +// the error was not registered. +func TranslateError(from error) (*errors.Error, bool) { + if err, ok := errorMap[from]; ok { + return err, true + } + // Try to unwrap the error if we couldn't match an error + // exactly. This might mean that a package has its own + // error type. + for _, unwrap := range errorUnwrappers { + if err, ok := unwrap(from); ok { + return err, true + } + } + return nil, false +} + +// These errors are significant because ptrace syscall exit tracing can +// observe them. +// +// For all of the following errors, if the syscall is not interrupted by a +// signal delivered to a user handler, the syscall is restarted. +var ( + // ERESTARTSYS is returned by an interrupted syscall to indicate that it + // should be converted to EINTR if interrupted by a signal delivered to a + // user handler without SA_RESTART set, and restarted otherwise. + ERESTARTSYS = errors.New(errno.ERESTARTSYS, "to be restarted if SA_RESTART is set") + + // ERESTARTNOINTR is returned by an interrupted syscall to indicate that it + // should always be restarted. + ERESTARTNOINTR = errors.New(errno.ERESTARTNOINTR, "to be restarted") + + // ERESTARTNOHAND is returned by an interrupted syscall to indicate that it + // should be converted to EINTR if interrupted by a signal delivered to a + // user handler, and restarted otherwise. + ERESTARTNOHAND = errors.New(errno.ERESTARTNOHAND, "to be restarted if no handler") + + // ERESTART_RESTARTBLOCK is returned by an interrupted syscall to indicate + // that it should be restarted using a custom function. The interrupted + // syscall must register a custom restart function by calling + // Task.SetRestartSyscallFn. + ERESTART_RESTARTBLOCK = errors.New(errno.ERESTART_RESTARTBLOCK, "interrupted by signal") +) + +var restartMap = map[int]*errors.Error{ + -int(errno.ERESTARTSYS): ERESTARTSYS, + -int(errno.ERESTARTNOINTR): ERESTARTNOINTR, + -int(errno.ERESTARTNOHAND): ERESTARTNOHAND, + -int(errno.ERESTART_RESTARTBLOCK): ERESTART_RESTARTBLOCK, +} + +// IsRestartError checks if a given error is a restart error. +func IsRestartError(err error) bool { + switch err { + case ERESTARTSYS, ERESTARTNOINTR, ERESTARTNOHAND, ERESTART_RESTARTBLOCK: + return true + default: + return false + } +} + +// SyscallRestartErrorFromReturn returns the SyscallRestartErrno represented by +// rv, the value in a syscall return register. +func SyscallRestartErrorFromReturn(rv uintptr) (*errors.Error, bool) { + err, ok := restartMap[int(rv)] + return err, ok +} diff --git a/pkg/errors/linuxerr/linuxerr_test.go b/pkg/errors/linuxerr/linuxerr_test.go index 5390c8a12..df7cd1c5a 100644 --- a/pkg/errors/linuxerr/linuxerr_test.go +++ b/pkg/errors/linuxerr/linuxerr_test.go @@ -12,10 +12,11 @@ // See the License for the specific language governing permissions and // limitations under the License. -package syserror_test +package linuxerr_test import ( "errors" + "fmt" "io" "io/fs" "syscall" @@ -25,7 +26,6 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux/errno" gErrors "gvisor.dev/gvisor/pkg/errors" "gvisor.dev/gvisor/pkg/errors/linuxerr" - "gvisor.dev/gvisor/pkg/syserror" ) var globalError error @@ -42,12 +42,6 @@ func BenchmarkAssignLinuxerr(b *testing.B) { } } -func BenchmarkAssignSyserror(b *testing.B) { - for i := b.N; i > 0; i-- { - globalError = linuxerr.ENOMSG - } -} - func BenchmarkCompareUnix(b *testing.B) { globalError = unix.EAGAIN j := 0 @@ -68,16 +62,6 @@ func BenchmarkCompareLinuxerr(b *testing.B) { } } -func BenchmarkCompareSyserror(b *testing.B) { - globalError = linuxerr.EAGAIN - j := 0 - for i := b.N; i > 0; i-- { - if globalError == linuxerr.EACCES { - j++ - } - } -} - func BenchmarkSwitchUnix(b *testing.B) { globalError = unix.EPERM j := 0 @@ -108,21 +92,6 @@ func BenchmarkSwitchLinuxerr(b *testing.B) { } } -func BenchmarkSwitchSyserror(b *testing.B) { - globalError = linuxerr.EPERM - j := 0 - for i := b.N; i > 0; i-- { - switch globalError { - case linuxerr.EACCES: - j++ - case linuxerr.EINTR: - j += 2 - case linuxerr.EAGAIN: - j += 3 - } - } -} - func BenchmarkReturnUnix(b *testing.B) { var localError error f := func() error { @@ -170,47 +139,40 @@ func BenchmarkConvertUnixLinuxerrZero(b *testing.B) { } type translationTestTable struct { - fn string errIn error - syscallErrorIn unix.Errno expectedBool bool - expectedTranslation unix.Errno + expectedTranslation *gErrors.Error } func TestErrorTranslation(t *testing.T) { - myError := errors.New("My test error") - myError2 := errors.New("Another test error") testTable := []translationTestTable{ - {"TranslateError", myError, 0, false, 0}, - {"TranslateError", myError2, 0, false, 0}, - {"AddErrorTranslation", myError, unix.EAGAIN, true, 0}, - {"AddErrorTranslation", myError, unix.EAGAIN, false, 0}, - {"AddErrorTranslation", myError, unix.EPERM, false, 0}, - {"TranslateError", myError, 0, true, unix.EAGAIN}, - {"TranslateError", myError2, 0, false, 0}, - {"AddErrorTranslation", myError2, unix.EPERM, true, 0}, - {"AddErrorTranslation", myError2, unix.EPERM, false, 0}, - {"AddErrorTranslation", myError2, unix.EAGAIN, false, 0}, - {"TranslateError", myError, 0, true, unix.EAGAIN}, - {"TranslateError", myError2, 0, true, unix.EPERM}, + { + errIn: linuxerr.ENOENT, + }, + { + errIn: unix.ENOENT, + }, + { + errIn: linuxerr.ErrInterrupted, + expectedBool: true, + expectedTranslation: linuxerr.EINTR, + }, + { + errIn: linuxerr.ERESTART_RESTARTBLOCK, + }, + { + errIn: errors.New("some new error"), + }, } for _, tt := range testTable { - switch tt.fn { - case "TranslateError": - err, ok := syserror.TranslateError(tt.errIn) - if ok != tt.expectedBool { - t.Fatalf("%v(%v) => %v expected %v", tt.fn, tt.errIn, ok, tt.expectedBool) + t.Run(fmt.Sprintf("err: %v %T", tt.errIn, tt.errIn), func(t *testing.T) { + err, ok := linuxerr.TranslateError(tt.errIn) + if (!tt.expectedBool && err != nil) || (tt.expectedBool != ok) { + t.Fatalf("%v => %v %v expected %v err: nil", tt.errIn, err, ok, tt.expectedBool) } else if err != tt.expectedTranslation { - t.Fatalf("%v(%v) (error) => %v expected %v", tt.fn, tt.errIn, err, tt.expectedTranslation) - } - case "AddErrorTranslation": - ok := syserror.AddErrorTranslation(tt.errIn, tt.syscallErrorIn) - if ok != tt.expectedBool { - t.Fatalf("%v(%v) => %v expected %v", tt.fn, tt.errIn, ok, tt.expectedBool) + t.Fatalf("%v => %v expected %v", tt.errIn, err, tt.expectedTranslation) } - default: - t.Fatalf("Unknown function %v", tt.fn) - } + }) } } -- cgit v1.2.3