Reduce map lookups in syserr

PiperOrigin-RevId: 208755352
Change-Id: Ia24630f452a4a42940ab73a8113a2fd5ea2cfca2

4 files changed, 210 insertions, 313 deletions

diff --git a/pkg/syserr/BUILD b/pkg/syserr/BUILD
index c0850f3d9..5dd2e90bb 100644
--- a/pkg/syserr/BUILD
+++ b/pkg/syserr/BUILD
@@ -6,7 +6,6 @@ go_library(
     name = "syserr",
     srcs = [
         "host_linux.go",
-        "linuxabi.go",
         "netstack.go",
         "syserr.go",
     ],
diff --git a/pkg/syserr/host_linux.go b/pkg/syserr/host_linux.go
index ffd78e8f8..22009a799 100644
--- a/pkg/syserr/host_linux.go
+++ b/pkg/syserr/host_linux.go
@@ -17,144 +17,30 @@
 package syserr
 
 import (
+	"fmt"
 	"syscall"
 )
 
-var linuxHostTranslations = map[syscall.Errno]*Error{
-	syscall.EPERM:           ErrNotPermitted,
-	syscall.ENOENT:          ErrNoFileOrDir,
-	syscall.ESRCH:           ErrNoProcess,
-	syscall.EINTR:           ErrInterrupted,
-	syscall.EIO:             ErrIO,
-	syscall.ENXIO:           ErrDeviceOrAddress,
-	syscall.E2BIG:           ErrTooManyArgs,
-	syscall.ENOEXEC:         ErrEcec,
-	syscall.EBADF:           ErrBadFD,
-	syscall.ECHILD:          ErrNoChild,
-	syscall.EAGAIN:          ErrTryAgain,
-	syscall.ENOMEM:          ErrNoMemory,
-	syscall.EACCES:          ErrPermissionDenied,
-	syscall.EFAULT:          ErrBadAddress,
-	syscall.ENOTBLK:         ErrNotBlockDevice,
-	syscall.EBUSY:           ErrBusy,
-	syscall.EEXIST:          ErrExists,
-	syscall.EXDEV:           ErrCrossDeviceLink,
-	syscall.ENODEV:          ErrNoDevice,
-	syscall.ENOTDIR:         ErrNotDir,
-	syscall.EISDIR:          ErrIsDir,
-	syscall.EINVAL:          ErrInvalidArgument,
-	syscall.ENFILE:          ErrFileTableOverflow,
-	syscall.EMFILE:          ErrTooManyOpenFiles,
-	syscall.ENOTTY:          ErrNotTTY,
-	syscall.ETXTBSY:         ErrTestFileBusy,
-	syscall.EFBIG:           ErrFileTooBig,
-	syscall.ENOSPC:          ErrNoSpace,
-	syscall.ESPIPE:          ErrIllegalSeek,
-	syscall.EROFS:           ErrReadOnlyFS,
-	syscall.EMLINK:          ErrTooManyLinks,
-	syscall.EPIPE:           ErrBrokenPipe,
-	syscall.EDOM:            ErrDomain,
-	syscall.ERANGE:          ErrRange,
-	syscall.EDEADLOCK:       ErrDeadlock,
-	syscall.ENAMETOOLONG:    ErrNameTooLong,
-	syscall.ENOLCK:          ErrNoLocksAvailable,
-	syscall.ENOSYS:          ErrInvalidSyscall,
-	syscall.ENOTEMPTY:       ErrDirNotEmpty,
-	syscall.ELOOP:           ErrLinkLoop,
-	syscall.ENOMSG:          ErrNoMessage,
-	syscall.EIDRM:           ErrIdentifierRemoved,
-	syscall.ECHRNG:          ErrChannelOutOfRange,
-	syscall.EL2NSYNC:        ErrLevelTwoNotSynced,
-	syscall.EL3HLT:          ErrLevelThreeHalted,
-	syscall.EL3RST:          ErrLevelThreeReset,
-	syscall.ELNRNG:          ErrLinkNumberOutOfRange,
-	syscall.EUNATCH:         ErrProtocolDriverNotAttached,
-	syscall.ENOCSI:          ErrNoCSIAvailable,
-	syscall.EL2HLT:          ErrLevelTwoHalted,
-	syscall.EBADE:           ErrInvalidExchange,
-	syscall.EBADR:           ErrInvalidRequestDescriptor,
-	syscall.EXFULL:          ErrExchangeFull,
-	syscall.ENOANO:          ErrNoAnode,
-	syscall.EBADRQC:         ErrInvalidRequestCode,
-	syscall.EBADSLT:         ErrInvalidSlot,
-	syscall.EBFONT:          ErrBadFontFile,
-	syscall.ENOSTR:          ErrNotStream,
-	syscall.ENODATA:         ErrNoDataAvailable,
-	syscall.ETIME:           ErrTimerExpired,
-	syscall.ENOSR:           ErrStreamsResourceDepleted,
-	syscall.ENONET:          ErrMachineNotOnNetwork,
-	syscall.ENOPKG:          ErrPackageNotInstalled,
-	syscall.EREMOTE:         ErrIsRemote,
-	syscall.ENOLINK:         ErrNoLink,
-	syscall.EADV:            ErrAdvertise,
-	syscall.ESRMNT:          ErrSRMount,
-	syscall.ECOMM:           ErrSendCommunication,
-	syscall.EPROTO:          ErrProtocol,
-	syscall.EMULTIHOP:       ErrMultihopAttempted,
-	syscall.EDOTDOT:         ErrRFS,
-	syscall.EBADMSG:         ErrInvalidDataMessage,
-	syscall.EOVERFLOW:       ErrOverflow,
-	syscall.ENOTUNIQ:        ErrNetworkNameNotUnique,
-	syscall.EBADFD:          ErrFDInBadState,
-	syscall.EREMCHG:         ErrRemoteAddressChanged,
-	syscall.ELIBACC:         ErrSharedLibraryInaccessible,
-	syscall.ELIBBAD:         ErrCorruptedSharedLibrary,
-	syscall.ELIBSCN:         ErrLibSectionCorrupted,
-	syscall.ELIBMAX:         ErrTooManySharedLibraries,
-	syscall.ELIBEXEC:        ErrSharedLibraryExeced,
-	syscall.EILSEQ:          ErrIllegalByteSequence,
-	syscall.ERESTART:        ErrShouldRestart,
-	syscall.ESTRPIPE:        ErrStreamPipe,
-	syscall.EUSERS:          ErrTooManyUsers,
-	syscall.ENOTSOCK:        ErrNotASocket,
-	syscall.EDESTADDRREQ:    ErrDestinationAddressRequired,
-	syscall.EMSGSIZE:        ErrMessageTooLong,
-	syscall.EPROTOTYPE:      ErrWrongProtocolForSocket,
-	syscall.ENOPROTOOPT:     ErrProtocolNotAvailable,
-	syscall.EPROTONOSUPPORT: ErrProtocolNotSupported,
-	syscall.ESOCKTNOSUPPORT: ErrSocketNotSupported,
-	syscall.EOPNOTSUPP:      ErrEndpointOperation,
-	syscall.EPFNOSUPPORT:    ErrProtocolFamilyNotSupported,
-	syscall.EAFNOSUPPORT:    ErrAddressFamilyNotSupported,
-	syscall.EADDRINUSE:      ErrAddressInUse,
-	syscall.EADDRNOTAVAIL:   ErrAddressNotAvailable,
-	syscall.ENETDOWN:        ErrNetworkDown,
-	syscall.ENETUNREACH:     ErrNetworkUnreachable,
-	syscall.ENETRESET:       ErrNetworkReset,
-	syscall.ECONNABORTED:    ErrConnectionAborted,
-	syscall.ECONNRESET:      ErrConnectionReset,
-	syscall.ENOBUFS:         ErrNoBufferSpace,
-	syscall.EISCONN:         ErrAlreadyConnected,
-	syscall.ENOTCONN:        ErrNotConnected,
-	syscall.ESHUTDOWN:       ErrShutdown,
-	syscall.ETOOMANYREFS:    ErrTooManyRefs,
-	syscall.ETIMEDOUT:       ErrTimedOut,
-	syscall.ECONNREFUSED:    ErrConnectionRefused,
-	syscall.EHOSTDOWN:       ErrHostDown,
-	syscall.EHOSTUNREACH:    ErrNoRoute,
-	syscall.EALREADY:        ErrAlreadyInProgress,
-	syscall.EINPROGRESS:     ErrInProgress,
-	syscall.ESTALE:          ErrStaleFileHandle,
-	syscall.EUCLEAN:         ErrStructureNeedsCleaning,
-	syscall.ENOTNAM:         ErrIsNamedFile,
-	syscall.EREMOTEIO:       ErrRemoteIO,
-	syscall.EDQUOT:          ErrQuotaExceeded,
-	syscall.ENOMEDIUM:       ErrNoMedium,
-	syscall.EMEDIUMTYPE:     ErrWrongMediumType,
-	syscall.ECANCELED:       ErrCanceled,
-	syscall.ENOKEY:          ErrNoKey,
-	syscall.EKEYEXPIRED:     ErrKeyExpired,
-	syscall.EKEYREVOKED:     ErrKeyRevoked,
-	syscall.EKEYREJECTED:    ErrKeyRejected,
-	syscall.EOWNERDEAD:      ErrOwnerDied,
-	syscall.ENOTRECOVERABLE: ErrNotRecoverable,
+const maxErrno = 134
+
+type linuxHostTranslation struct {
+	err *Error
+	ok  bool
 }
 
+var linuxHostTranslations [maxErrno]linuxHostTranslation
+
 // FromHost translates a syscall.Errno to a corresponding Error value.
 func FromHost(err syscall.Errno) *Error {
-	e, ok := linuxHostTranslations[err]
-	if !ok {
-		panic("Unknown host errno " + err.Error())
+	if err < 0 || int(err) >= len(linuxHostTranslations) || !linuxHostTranslations[err].ok {
+		panic(fmt.Sprintf("unknown host errno %q (%d)", err.Error(), err))
+	}
+	return linuxHostTranslations[err].err
+}
+
+func addLinuxHostTranslation(host syscall.Errno, trans *Error) {
+	if linuxHostTranslations[host].ok {
+		panic(fmt.Sprintf("duplicate translation for host errno %q (%d)", host.Error(), host))
 	}
-	return e
+	linuxHostTranslations[host] = linuxHostTranslation{err: trans, ok: true}
 }
diff --git a/pkg/syserr/linuxabi.go b/pkg/syserr/linuxabi.go
deleted file mode 100644
index 71e3d1a81..000000000
--- a/pkg/syserr/linuxabi.go
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright 2018 Google Inc.
-//
-// 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 syserr
-
-import (
-	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
-)
-
-var linuxABITranslations = map[*Error]*linux.Errno{}
-
-// ToLinux translates an Error to a corresponding *linux.Errno value.
-func ToLinux(err *Error) *linux.Errno {
-	le, ok := linuxABITranslations[err]
-	if !ok {
-		panic("No Linux ABI translation available for " + err.String())
-	}
-	return le
-}
diff --git a/pkg/syserr/syserr.go b/pkg/syserr/syserr.go
index 5d9fa24de..dba6cb7de 100644
--- a/pkg/syserr/syserr.go
+++ b/pkg/syserr/syserr.go
@@ -27,30 +27,43 @@ import (
 
 // Error represents an internal error.
 type Error struct {
-	string
+	// message is the human readable form of this Error.
+	message string
+
+	// noTranslation indicates that this Error cannot be translated to a
+	// linux.Errno.
+	noTranslation bool
+
+	// errno is the linux.Errno this Error should be translated to. nil means
+	// that this Error should be translated to a nil linux.Errno.
+	errno *linux.Errno
 }
 
 // New creates a new Error and adds a translation for it.
 //
 // New must only be called at init.
 func New(message string, linuxTranslation *linux.Errno) *Error {
-	err := &Error{message}
-	linuxABITranslations[err] = linuxTranslation
+	err := &Error{message: message, errno: linuxTranslation}
 
-	// TODO: Remove this.
 	if linuxTranslation == nil {
-		linuxBackwardsTranslations[err] = nil
-	} else {
-		e := error(syscall.Errno(linuxTranslation.Number()))
-		// syserror.ErrWouldBlock gets translated to syserror.EWOULDBLOCK and
-		// enables proper blocking semantics. This should temporary address the
-		// class of blocking bugs that keep popping up with the current state of
-		// the error space.
-		if e == syserror.EWOULDBLOCK {
-			e = syserror.ErrWouldBlock
-		}
-		linuxBackwardsTranslations[err] = e
+		return err
+	}
+
+	// TODO: Remove this.
+	errno := linuxTranslation.Number()
+	if errno <= 0 || errno >= len(linuxBackwardsTranslations) {
+		panic(fmt.Sprint("invalid errno: ", errno))
+	}
+
+	e := error(syscall.Errno(errno))
+	// syserror.ErrWouldBlock gets translated to syserror.EWOULDBLOCK and
+	// enables proper blocking semantics. This should temporary address the
+	// class of blocking bugs that keep popping up with the current state of
+	// the error space.
+	if e == syserror.EWOULDBLOCK {
+		e = syserror.ErrWouldBlock
 	}
+	linuxBackwardsTranslations[errno] = linuxBackwardsTranslation{err: e, ok: true}
 
 	return err
 }
@@ -58,7 +71,13 @@ func New(message string, linuxTranslation *linux.Errno) *Error {
 // NewWithoutTranslation creates a new Error. If translation is attempted on
 // the error, translation will fail.
 func NewWithoutTranslation(message string) *Error {
-	return &Error{message}
+	return &Error{message: message, noTranslation: true}
+}
+
+func newWithHost(message string, linuxTranslation *linux.Errno, hostErrno syscall.Errno) *Error {
+	e := New(message, linuxTranslation)
+	addLinuxHostTranslation(hostErrno, e)
+	return e
 }
 
 // String implements fmt.Stringer.String.
@@ -66,11 +85,16 @@ func (e *Error) String() string {
 	if e == nil {
 		return "<nil>"
 	}
-	return e.string
+	return e.message
+}
+
+type linuxBackwardsTranslation struct {
+	err error
+	ok  bool
 }
 
 // TODO: Remove this.
-var linuxBackwardsTranslations = map[*Error]error{}
+var linuxBackwardsTranslations [maxErrno]linuxBackwardsTranslation
 
 // ToError translates an Error to a corresponding error value.
 //
@@ -79,11 +103,26 @@ func (e *Error) ToError() error {
 	if e == nil {
 		return nil
 	}
-	err, ok := linuxBackwardsTranslations[e]
-	if !ok {
-		panic(fmt.Sprintf("unknown error: %q", e.string))
+	if e.noTranslation {
+		panic(fmt.Sprintf("error %q does not support translation", e.message))
 	}
-	return err
+	if e.errno == nil {
+		return nil
+	}
+	errno := e.errno.Number()
+	if errno <= 0 || errno >= len(linuxBackwardsTranslations) || !linuxBackwardsTranslations[errno].ok {
+		panic(fmt.Sprintf("unknown error %q (%d)", e.message, errno))
+	}
+	return linuxBackwardsTranslations[errno].err
+}
+
+// ToLinux converts the Error to a Linux ABI error that can be returned to the
+// application.
+func (e *Error) ToLinux() *linux.Errno {
+	if e.noTranslation {
+		panic(fmt.Sprintf("No Linux ABI translation available for %q", e.message))
+	}
+	return e.errno
 }
 
 // TODO: Remove or replace most of these errors.
@@ -91,134 +130,137 @@ func (e *Error) ToError() error {
 // Some of the errors should be replaced with package specific errors and
 // others should be removed entirely.
 var (
-	ErrNotPermitted               = New("operation not permitted", linux.EPERM)
-	ErrNoFileOrDir                = New("no such file or directory", linux.ENOENT)
-	ErrNoProcess                  = New("no such process", linux.ESRCH)
-	ErrInterrupted                = New("interrupted system call", linux.EINTR)
-	ErrIO                         = New("I/O error", linux.EIO)
-	ErrDeviceOrAddress            = New("no such device or address", linux.ENXIO)
-	ErrTooManyArgs                = New("argument list too long", linux.E2BIG)
-	ErrEcec                       = New("exec format error", linux.ENOEXEC)
-	ErrBadFD                      = New("bad file number", linux.EBADF)
-	ErrNoChild                    = New("no child processes", linux.ECHILD)
-	ErrTryAgain                   = New("try again", linux.EAGAIN)
-	ErrNoMemory                   = New("out of memory", linux.ENOMEM)
-	ErrPermissionDenied           = New("permission denied", linux.EACCES)
-	ErrBadAddress                 = New("bad address", linux.EFAULT)
-	ErrNotBlockDevice             = New("block device required", linux.ENOTBLK)
-	ErrBusy                       = New("device or resource busy", linux.EBUSY)
-	ErrExists                     = New("file exists", linux.EEXIST)
-	ErrCrossDeviceLink            = New("cross-device link", linux.EXDEV)
-	ErrNoDevice                   = New("no such device", linux.ENODEV)
-	ErrNotDir                     = New("not a directory", linux.ENOTDIR)
-	ErrIsDir                      = New("is a directory", linux.EISDIR)
-	ErrInvalidArgument            = New("invalid argument", linux.EINVAL)
-	ErrFileTableOverflow          = New("file table overflow", linux.ENFILE)
-	ErrTooManyOpenFiles           = New("too many open files", linux.EMFILE)
-	ErrNotTTY                     = New("not a typewriter", linux.ENOTTY)
-	ErrTestFileBusy               = New("text file busy", linux.ETXTBSY)
-	ErrFileTooBig                 = New("file too large", linux.EFBIG)
-	ErrNoSpace                    = New("no space left on device", linux.ENOSPC)
-	ErrIllegalSeek                = New("illegal seek", linux.ESPIPE)
-	ErrReadOnlyFS                 = New("read-only file system", linux.EROFS)
-	ErrTooManyLinks               = New("too many links", linux.EMLINK)
-	ErrBrokenPipe                 = New("broken pipe", linux.EPIPE)
-	ErrDomain                     = New("math argument out of domain of func", linux.EDOM)
-	ErrRange                      = New("math result not representable", linux.ERANGE)
-	ErrDeadlock                   = New("resource deadlock would occur", linux.EDEADLOCK)
-	ErrNameTooLong                = New("file name too long", linux.ENAMETOOLONG)
-	ErrNoLocksAvailable           = New("no record locks available", linux.ENOLCK)
-	ErrInvalidSyscall             = New("invalid system call number", linux.ENOSYS)
-	ErrDirNotEmpty                = New("directory not empty", linux.ENOTEMPTY)
-	ErrLinkLoop                   = New("too many symbolic links encountered", linux.ELOOP)
-	ErrWouldBlock                 = New("operation would block", linux.EWOULDBLOCK)
-	ErrNoMessage                  = New("no message of desired type", linux.ENOMSG)
-	ErrIdentifierRemoved          = New("identifier removed", linux.EIDRM)
-	ErrChannelOutOfRange          = New("channel number out of range", linux.ECHRNG)
-	ErrLevelTwoNotSynced          = New("level 2 not synchronized", linux.EL2NSYNC)
-	ErrLevelThreeHalted           = New("level 3 halted", linux.EL3HLT)
-	ErrLevelThreeReset            = New("level 3 reset", linux.EL3RST)
-	ErrLinkNumberOutOfRange       = New("link number out of range", linux.ELNRNG)
-	ErrProtocolDriverNotAttached  = New("protocol driver not attached", linux.EUNATCH)
-	ErrNoCSIAvailable             = New("no CSI structure available", linux.ENOCSI)
-	ErrLevelTwoHalted             = New("level 2 halted", linux.EL2HLT)
-	ErrInvalidExchange            = New("invalid exchange", linux.EBADE)
-	ErrInvalidRequestDescriptor   = New("invalid request descriptor", linux.EBADR)
-	ErrExchangeFull               = New("exchange full", linux.EXFULL)
-	ErrNoAnode                    = New("no anode", linux.ENOANO)
-	ErrInvalidRequestCode         = New("invalid request code", linux.EBADRQC)
-	ErrInvalidSlot                = New("invalid slot", linux.EBADSLT)
-	ErrBadFontFile                = New("bad font file format", linux.EBFONT)
-	ErrNotStream                  = New("device not a stream", linux.ENOSTR)
-	ErrNoDataAvailable            = New("no data available", linux.ENODATA)
-	ErrTimerExpired               = New("timer expired", linux.ETIME)
-	ErrStreamsResourceDepleted    = New("out of streams resources", linux.ENOSR)
-	ErrMachineNotOnNetwork        = New("machine is not on the network", linux.ENONET)
-	ErrPackageNotInstalled        = New("package not installed", linux.ENOPKG)
-	ErrIsRemote                   = New("object is remote", linux.EREMOTE)
-	ErrNoLink                     = New("link has been severed", linux.ENOLINK)
-	ErrAdvertise                  = New("advertise error", linux.EADV)
-	ErrSRMount                    = New("srmount error", linux.ESRMNT)
-	ErrSendCommunication          = New("communication error on send", linux.ECOMM)
-	ErrProtocol                   = New("protocol error", linux.EPROTO)
-	ErrMultihopAttempted          = New("multihop attempted", linux.EMULTIHOP)
-	ErrRFS                        = New("RFS specific error", linux.EDOTDOT)
-	ErrInvalidDataMessage         = New("not a data message", linux.EBADMSG)
-	ErrOverflow                   = New("value too large for defined data type", linux.EOVERFLOW)
-	ErrNetworkNameNotUnique       = New("name not unique on network", linux.ENOTUNIQ)
-	ErrFDInBadState               = New("file descriptor in bad state", linux.EBADFD)
-	ErrRemoteAddressChanged       = New("remote address changed", linux.EREMCHG)
-	ErrSharedLibraryInaccessible  = New("can not access a needed shared library", linux.ELIBACC)
-	ErrCorruptedSharedLibrary     = New("accessing a corrupted shared library", linux.ELIBBAD)
-	ErrLibSectionCorrupted        = New(".lib section in a.out corrupted", linux.ELIBSCN)
-	ErrTooManySharedLibraries     = New("attempting to link in too many shared libraries", linux.ELIBMAX)
-	ErrSharedLibraryExeced        = New("cannot exec a shared library directly", linux.ELIBEXEC)
-	ErrIllegalByteSequence        = New("illegal byte sequence", linux.EILSEQ)
-	ErrShouldRestart              = New("interrupted system call should be restarted", linux.ERESTART)
-	ErrStreamPipe                 = New("streams pipe error", linux.ESTRPIPE)
-	ErrTooManyUsers               = New("too many users", linux.EUSERS)
-	ErrNotASocket                 = New("socket operation on non-socket", linux.ENOTSOCK)
-	ErrDestinationAddressRequired = New("destination address required", linux.EDESTADDRREQ)
-	ErrMessageTooLong             = New("message too long", linux.EMSGSIZE)
-	ErrWrongProtocolForSocket     = New("protocol wrong type for socket", linux.EPROTOTYPE)
-	ErrProtocolNotAvailable       = New("protocol not available", linux.ENOPROTOOPT)
-	ErrProtocolNotSupported       = New("protocol not supported", linux.EPROTONOSUPPORT)
-	ErrSocketNotSupported         = New("socket type not supported", linux.ESOCKTNOSUPPORT)
-	ErrEndpointOperation          = New("operation not supported on transport endpoint", linux.EOPNOTSUPP)
-	ErrProtocolFamilyNotSupported = New("protocol family not supported", linux.EPFNOSUPPORT)
-	ErrAddressFamilyNotSupported  = New("address family not supported by protocol", linux.EAFNOSUPPORT)
-	ErrAddressInUse               = New("address already in use", linux.EADDRINUSE)
-	ErrAddressNotAvailable        = New("cannot assign requested address", linux.EADDRNOTAVAIL)
-	ErrNetworkDown                = New("network is down", linux.ENETDOWN)
-	ErrNetworkUnreachable         = New("network is unreachable", linux.ENETUNREACH)
-	ErrNetworkReset               = New("network dropped connection because of reset", linux.ENETRESET)
-	ErrConnectionAborted          = New("software caused connection abort", linux.ECONNABORTED)
-	ErrConnectionReset            = New("connection reset by peer", linux.ECONNRESET)
-	ErrNoBufferSpace              = New("no buffer space available", linux.ENOBUFS)
-	ErrAlreadyConnected           = New("transport endpoint is already connected", linux.EISCONN)
-	ErrNotConnected               = New("transport endpoint is not connected", linux.ENOTCONN)
-	ErrShutdown                   = New("cannot send after transport endpoint shutdown", linux.ESHUTDOWN)
-	ErrTooManyRefs                = New("too many references: cannot splice", linux.ETOOMANYREFS)
-	ErrTimedOut                   = New("connection timed out", linux.ETIMEDOUT)
-	ErrConnectionRefused          = New("connection refused", linux.ECONNREFUSED)
-	ErrHostDown                   = New("host is down", linux.EHOSTDOWN)
-	ErrNoRoute                    = New("no route to host", linux.EHOSTUNREACH)
-	ErrAlreadyInProgress          = New("operation already in progress", linux.EALREADY)
-	ErrInProgress                 = New("operation now in progress", linux.EINPROGRESS)
-	ErrStaleFileHandle            = New("stale file handle", linux.ESTALE)
-	ErrStructureNeedsCleaning     = New("structure needs cleaning", linux.EUCLEAN)
-	ErrIsNamedFile                = New("is a named type file", linux.ENOTNAM)
-	ErrRemoteIO                   = New("remote I/O error", linux.EREMOTEIO)
-	ErrQuotaExceeded              = New("quota exceeded", linux.EDQUOT)
-	ErrNoMedium                   = New("no medium found", linux.ENOMEDIUM)
-	ErrWrongMediumType            = New("wrong medium type", linux.EMEDIUMTYPE)
-	ErrCanceled                   = New("operation Canceled", linux.ECANCELED)
-	ErrNoKey                      = New("required key not available", linux.ENOKEY)
-	ErrKeyExpired                 = New("key has expired", linux.EKEYEXPIRED)
-	ErrKeyRevoked                 = New("key has been revoked", linux.EKEYREVOKED)
-	ErrKeyRejected                = New("key was rejected by service", linux.EKEYREJECTED)
-	ErrOwnerDied                  = New("owner died", linux.EOWNERDEAD)
-	ErrNotRecoverable             = New("state not recoverable", linux.ENOTRECOVERABLE)
+	ErrNotPermitted               = newWithHost("operation not permitted", linux.EPERM, syscall.EPERM)
+	ErrNoFileOrDir                = newWithHost("no such file or directory", linux.ENOENT, syscall.ENOENT)
+	ErrNoProcess                  = newWithHost("no such process", linux.ESRCH, syscall.ESRCH)
+	ErrInterrupted                = newWithHost("interrupted system call", linux.EINTR, syscall.EINTR)
+	ErrIO                         = newWithHost("I/O error", linux.EIO, syscall.EIO)
+	ErrDeviceOrAddress            = newWithHost("no such device or address", linux.ENXIO, syscall.ENXIO)
+	ErrTooManyArgs                = newWithHost("argument list too long", linux.E2BIG, syscall.E2BIG)
+	ErrEcec                       = newWithHost("exec format error", linux.ENOEXEC, syscall.ENOEXEC)
+	ErrBadFD                      = newWithHost("bad file number", linux.EBADF, syscall.EBADF)
+	ErrNoChild                    = newWithHost("no child processes", linux.ECHILD, syscall.ECHILD)
+	ErrTryAgain                   = newWithHost("try again", linux.EAGAIN, syscall.EAGAIN)
+	ErrNoMemory                   = newWithHost("out of memory", linux.ENOMEM, syscall.ENOMEM)
+	ErrPermissionDenied           = newWithHost("permission denied", linux.EACCES, syscall.EACCES)
+	ErrBadAddress                 = newWithHost("bad address", linux.EFAULT, syscall.EFAULT)
+	ErrNotBlockDevice             = newWithHost("block device required", linux.ENOTBLK, syscall.ENOTBLK)
+	ErrBusy                       = newWithHost("device or resource busy", linux.EBUSY, syscall.EBUSY)
+	ErrExists                     = newWithHost("file exists", linux.EEXIST, syscall.EEXIST)
+	ErrCrossDeviceLink            = newWithHost("cross-device link", linux.EXDEV, syscall.EXDEV)
+	ErrNoDevice                   = newWithHost("no such device", linux.ENODEV, syscall.ENODEV)
+	ErrNotDir                     = newWithHost("not a directory", linux.ENOTDIR, syscall.ENOTDIR)
+	ErrIsDir                      = newWithHost("is a directory", linux.EISDIR, syscall.EISDIR)
+	ErrInvalidArgument            = newWithHost("invalid argument", linux.EINVAL, syscall.EINVAL)
+	ErrFileTableOverflow          = newWithHost("file table overflow", linux.ENFILE, syscall.ENFILE)
+	ErrTooManyOpenFiles           = newWithHost("too many open files", linux.EMFILE, syscall.EMFILE)
+	ErrNotTTY                     = newWithHost("not a typewriter", linux.ENOTTY, syscall.ENOTTY)
+	ErrTestFileBusy               = newWithHost("text file busy", linux.ETXTBSY, syscall.ETXTBSY)
+	ErrFileTooBig                 = newWithHost("file too large", linux.EFBIG, syscall.EFBIG)
+	ErrNoSpace                    = newWithHost("no space left on device", linux.ENOSPC, syscall.ENOSPC)
+	ErrIllegalSeek                = newWithHost("illegal seek", linux.ESPIPE, syscall.ESPIPE)
+	ErrReadOnlyFS                 = newWithHost("read-only file system", linux.EROFS, syscall.EROFS)
+	ErrTooManyLinks               = newWithHost("too many links", linux.EMLINK, syscall.EMLINK)
+	ErrBrokenPipe                 = newWithHost("broken pipe", linux.EPIPE, syscall.EPIPE)
+	ErrDomain                     = newWithHost("math argument out of domain of func", linux.EDOM, syscall.EDOM)
+	ErrRange                      = newWithHost("math result not representable", linux.ERANGE, syscall.ERANGE)
+	ErrDeadlock                   = newWithHost("resource deadlock would occur", linux.EDEADLOCK, syscall.EDEADLOCK)
+	ErrNameTooLong                = newWithHost("file name too long", linux.ENAMETOOLONG, syscall.ENAMETOOLONG)
+	ErrNoLocksAvailable           = newWithHost("no record locks available", linux.ENOLCK, syscall.ENOLCK)
+	ErrInvalidSyscall             = newWithHost("invalid system call number", linux.ENOSYS, syscall.ENOSYS)
+	ErrDirNotEmpty                = newWithHost("directory not empty", linux.ENOTEMPTY, syscall.ENOTEMPTY)
+	ErrLinkLoop                   = newWithHost("too many symbolic links encountered", linux.ELOOP, syscall.ELOOP)
+	ErrNoMessage                  = newWithHost("no message of desired type", linux.ENOMSG, syscall.ENOMSG)
+	ErrIdentifierRemoved          = newWithHost("identifier removed", linux.EIDRM, syscall.EIDRM)
+	ErrChannelOutOfRange          = newWithHost("channel number out of range", linux.ECHRNG, syscall.ECHRNG)
+	ErrLevelTwoNotSynced          = newWithHost("level 2 not synchronized", linux.EL2NSYNC, syscall.EL2NSYNC)
+	ErrLevelThreeHalted           = newWithHost("level 3 halted", linux.EL3HLT, syscall.EL3HLT)
+	ErrLevelThreeReset            = newWithHost("level 3 reset", linux.EL3RST, syscall.EL3RST)
+	ErrLinkNumberOutOfRange       = newWithHost("link number out of range", linux.ELNRNG, syscall.ELNRNG)
+	ErrProtocolDriverNotAttached  = newWithHost("protocol driver not attached", linux.EUNATCH, syscall.EUNATCH)
+	ErrNoCSIAvailable             = newWithHost("no CSI structure available", linux.ENOCSI, syscall.ENOCSI)
+	ErrLevelTwoHalted             = newWithHost("level 2 halted", linux.EL2HLT, syscall.EL2HLT)
+	ErrInvalidExchange            = newWithHost("invalid exchange", linux.EBADE, syscall.EBADE)
+	ErrInvalidRequestDescriptor   = newWithHost("invalid request descriptor", linux.EBADR, syscall.EBADR)
+	ErrExchangeFull               = newWithHost("exchange full", linux.EXFULL, syscall.EXFULL)
+	ErrNoAnode                    = newWithHost("no anode", linux.ENOANO, syscall.ENOANO)
+	ErrInvalidRequestCode         = newWithHost("invalid request code", linux.EBADRQC, syscall.EBADRQC)
+	ErrInvalidSlot                = newWithHost("invalid slot", linux.EBADSLT, syscall.EBADSLT)
+	ErrBadFontFile                = newWithHost("bad font file format", linux.EBFONT, syscall.EBFONT)
+	ErrNotStream                  = newWithHost("device not a stream", linux.ENOSTR, syscall.ENOSTR)
+	ErrNoDataAvailable            = newWithHost("no data available", linux.ENODATA, syscall.ENODATA)
+	ErrTimerExpired               = newWithHost("timer expired", linux.ETIME, syscall.ETIME)
+	ErrStreamsResourceDepleted    = newWithHost("out of streams resources", linux.ENOSR, syscall.ENOSR)
+	ErrMachineNotOnNetwork        = newWithHost("machine is not on the network", linux.ENONET, syscall.ENONET)
+	ErrPackageNotInstalled        = newWithHost("package not installed", linux.ENOPKG, syscall.ENOPKG)
+	ErrIsRemote                   = newWithHost("object is remote", linux.EREMOTE, syscall.EREMOTE)
+	ErrNoLink                     = newWithHost("link has been severed", linux.ENOLINK, syscall.ENOLINK)
+	ErrAdvertise                  = newWithHost("advertise error", linux.EADV, syscall.EADV)
+	ErrSRMount                    = newWithHost("srmount error", linux.ESRMNT, syscall.ESRMNT)
+	ErrSendCommunication          = newWithHost("communication error on send", linux.ECOMM, syscall.ECOMM)
+	ErrProtocol                   = newWithHost("protocol error", linux.EPROTO, syscall.EPROTO)
+	ErrMultihopAttempted          = newWithHost("multihop attempted", linux.EMULTIHOP, syscall.EMULTIHOP)
+	ErrRFS                        = newWithHost("RFS specific error", linux.EDOTDOT, syscall.EDOTDOT)
+	ErrInvalidDataMessage         = newWithHost("not a data message", linux.EBADMSG, syscall.EBADMSG)
+	ErrOverflow                   = newWithHost("value too large for defined data type", linux.EOVERFLOW, syscall.EOVERFLOW)
+	ErrNetworkNameNotUnique       = newWithHost("name not unique on network", linux.ENOTUNIQ, syscall.ENOTUNIQ)
+	ErrFDInBadState               = newWithHost("file descriptor in bad state", linux.EBADFD, syscall.EBADFD)
+	ErrRemoteAddressChanged       = newWithHost("remote address changed", linux.EREMCHG, syscall.EREMCHG)
+	ErrSharedLibraryInaccessible  = newWithHost("can not access a needed shared library", linux.ELIBACC, syscall.ELIBACC)
+	ErrCorruptedSharedLibrary     = newWithHost("accessing a corrupted shared library", linux.ELIBBAD, syscall.ELIBBAD)
+	ErrLibSectionCorrupted        = newWithHost(".lib section in a.out corrupted", linux.ELIBSCN, syscall.ELIBSCN)
+	ErrTooManySharedLibraries     = newWithHost("attempting to link in too many shared libraries", linux.ELIBMAX, syscall.ELIBMAX)
+	ErrSharedLibraryExeced        = newWithHost("cannot exec a shared library directly", linux.ELIBEXEC, syscall.ELIBEXEC)
+	ErrIllegalByteSequence        = newWithHost("illegal byte sequence", linux.EILSEQ, syscall.EILSEQ)
+	ErrShouldRestart              = newWithHost("interrupted system call should be restarted", linux.ERESTART, syscall.ERESTART)
+	ErrStreamPipe                 = newWithHost("streams pipe error", linux.ESTRPIPE, syscall.ESTRPIPE)
+	ErrTooManyUsers               = newWithHost("too many users", linux.EUSERS, syscall.EUSERS)
+	ErrNotASocket                 = newWithHost("socket operation on non-socket", linux.ENOTSOCK, syscall.ENOTSOCK)
+	ErrDestinationAddressRequired = newWithHost("destination address required", linux.EDESTADDRREQ, syscall.EDESTADDRREQ)
+	ErrMessageTooLong             = newWithHost("message too long", linux.EMSGSIZE, syscall.EMSGSIZE)
+	ErrWrongProtocolForSocket     = newWithHost("protocol wrong type for socket", linux.EPROTOTYPE, syscall.EPROTOTYPE)
+	ErrProtocolNotAvailable       = newWithHost("protocol not available", linux.ENOPROTOOPT, syscall.ENOPROTOOPT)
+	ErrProtocolNotSupported       = newWithHost("protocol not supported", linux.EPROTONOSUPPORT, syscall.EPROTONOSUPPORT)
+	ErrSocketNotSupported         = newWithHost("socket type not supported", linux.ESOCKTNOSUPPORT, syscall.ESOCKTNOSUPPORT)
+	ErrEndpointOperation          = newWithHost("operation not supported on transport endpoint", linux.EOPNOTSUPP, syscall.EOPNOTSUPP)
+	ErrProtocolFamilyNotSupported = newWithHost("protocol family not supported", linux.EPFNOSUPPORT, syscall.EPFNOSUPPORT)
+	ErrAddressFamilyNotSupported  = newWithHost("address family not supported by protocol", linux.EAFNOSUPPORT, syscall.EAFNOSUPPORT)
+	ErrAddressInUse               = newWithHost("address already in use", linux.EADDRINUSE, syscall.EADDRINUSE)
+	ErrAddressNotAvailable        = newWithHost("cannot assign requested address", linux.EADDRNOTAVAIL, syscall.EADDRNOTAVAIL)
+	ErrNetworkDown                = newWithHost("network is down", linux.ENETDOWN, syscall.ENETDOWN)
+	ErrNetworkUnreachable         = newWithHost("network is unreachable", linux.ENETUNREACH, syscall.ENETUNREACH)
+	ErrNetworkReset               = newWithHost("network dropped connection because of reset", linux.ENETRESET, syscall.ENETRESET)
+	ErrConnectionAborted          = newWithHost("software caused connection abort", linux.ECONNABORTED, syscall.ECONNABORTED)
+	ErrConnectionReset            = newWithHost("connection reset by peer", linux.ECONNRESET, syscall.ECONNRESET)
+	ErrNoBufferSpace              = newWithHost("no buffer space available", linux.ENOBUFS, syscall.ENOBUFS)
+	ErrAlreadyConnected           = newWithHost("transport endpoint is already connected", linux.EISCONN, syscall.EISCONN)
+	ErrNotConnected               = newWithHost("transport endpoint is not connected", linux.ENOTCONN, syscall.ENOTCONN)
+	ErrShutdown                   = newWithHost("cannot send after transport endpoint shutdown", linux.ESHUTDOWN, syscall.ESHUTDOWN)
+	ErrTooManyRefs                = newWithHost("too many references: cannot splice", linux.ETOOMANYREFS, syscall.ETOOMANYREFS)
+	ErrTimedOut                   = newWithHost("connection timed out", linux.ETIMEDOUT, syscall.ETIMEDOUT)
+	ErrConnectionRefused          = newWithHost("connection refused", linux.ECONNREFUSED, syscall.ECONNREFUSED)
+	ErrHostDown                   = newWithHost("host is down", linux.EHOSTDOWN, syscall.EHOSTDOWN)
+	ErrNoRoute                    = newWithHost("no route to host", linux.EHOSTUNREACH, syscall.EHOSTUNREACH)
+	ErrAlreadyInProgress          = newWithHost("operation already in progress", linux.EALREADY, syscall.EALREADY)
+	ErrInProgress                 = newWithHost("operation now in progress", linux.EINPROGRESS, syscall.EINPROGRESS)
+	ErrStaleFileHandle            = newWithHost("stale file handle", linux.ESTALE, syscall.ESTALE)
+	ErrStructureNeedsCleaning     = newWithHost("structure needs cleaning", linux.EUCLEAN, syscall.EUCLEAN)
+	ErrIsNamedFile                = newWithHost("is a named type file", linux.ENOTNAM, syscall.ENOTNAM)
+	ErrRemoteIO                   = newWithHost("remote I/O error", linux.EREMOTEIO, syscall.EREMOTEIO)
+	ErrQuotaExceeded              = newWithHost("quota exceeded", linux.EDQUOT, syscall.EDQUOT)
+	ErrNoMedium                   = newWithHost("no medium found", linux.ENOMEDIUM, syscall.ENOMEDIUM)
+	ErrWrongMediumType            = newWithHost("wrong medium type", linux.EMEDIUMTYPE, syscall.EMEDIUMTYPE)
+	ErrCanceled                   = newWithHost("operation canceled", linux.ECANCELED, syscall.ECANCELED)
+	ErrNoKey                      = newWithHost("required key not available", linux.ENOKEY, syscall.ENOKEY)
+	ErrKeyExpired                 = newWithHost("key has expired", linux.EKEYEXPIRED, syscall.EKEYEXPIRED)
+	ErrKeyRevoked                 = newWithHost("key has been revoked", linux.EKEYREVOKED, syscall.EKEYREVOKED)
+	ErrKeyRejected                = newWithHost("key was rejected by service", linux.EKEYREJECTED, syscall.EKEYREJECTED)
+	ErrOwnerDied                  = newWithHost("owner died", linux.EOWNERDEAD, syscall.EOWNERDEAD)
+	ErrNotRecoverable             = newWithHost("state not recoverable", linux.ENOTRECOVERABLE, syscall.ENOTRECOVERABLE)
+
+	// ErrWouldBlock translates to EWOULDBLOCK which is the same as EAGAIN
+	// on Linux.
+	ErrWouldBlock = New("operation would block", linux.EWOULDBLOCK)
 )
 
 // FromError converts a generic error to an *Error.