[syserror] Refactor linuxerr and error package.

Move Error struct to pkg/errors package for use in multiple places.
Move linuxerr static definitions under pkg/errors/linuxerr.
Add a lookup list for quick lookup of *errors.Error by errno. This is useful
when converting syserror errors and unix.Errno/syscall.Errrno values to
*errors.Error.
Update benchmarks routines to include conversions.

The below benchmarks show *errors.Error usage to be comparable to using
unix.Errno.

BenchmarkAssignUnix
BenchmarkAssignUnix-32                 	787875022	         1.284 ns/op
BenchmarkAssignLinuxerr
BenchmarkAssignLinuxerr-32             	1000000000	         1.209 ns/op
BenchmarkAssignSyserror
BenchmarkAssignSyserror-32             	759269229	         1.429 ns/op
BenchmarkCompareUnix
BenchmarkCompareUnix-32                	1000000000	         1.310 ns/op
BenchmarkCompareLinuxerr
BenchmarkCompareLinuxerr-32            	1000000000	         1.241 ns/op
BenchmarkCompareSyserror
BenchmarkCompareSyserror-32            	147196165	         8.248 ns/op
BenchmarkSwitchUnix
BenchmarkSwitchUnix-32                 	373233556	         3.664 ns/op
BenchmarkSwitchLinuxerr
BenchmarkSwitchLinuxerr-32             	476323929	         3.294 ns/op
BenchmarkSwitchSyserror
BenchmarkSwitchSyserror-32             	39293408	        29.62 ns/op
BenchmarkReturnUnix
BenchmarkReturnUnix-32                 	1000000000	         0.5042 ns/op
BenchmarkReturnLinuxerr
BenchmarkReturnLinuxerr-32             	1000000000	         0.8152 ns/op
BenchmarkConvertUnixLinuxerr
BenchmarkConvertUnixLinuxerr-32        	739948875	         1.547 ns/op
BenchmarkConvertUnixLinuxerrZero
BenchmarkConvertUnixLinuxerrZero-32    	977733974	         1.489 ns/op

PiperOrigin-RevId: 379806801

5 files changed, 646 insertions, 0 deletions

diff --git a/pkg/errors/BUILD b/pkg/errors/BUILD
new file mode 100644
index 000000000..36ea5da0c
--- /dev/null
+++ b/pkg/errors/BUILD
@@ -0,0 +1,10 @@
+load("//tools:defs.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "errors",
+    srcs = ["errors.go"],
+    visibility = ["//:sandbox"],
+    deps = ["//pkg/abi/linux/errno"],
+)
diff --git a/pkg/errors/errors.go b/pkg/errors/errors.go
new file mode 100644
index 000000000..7984a770e
--- /dev/null
+++ b/pkg/errors/errors.go
@@ -0,0 +1,40 @@
+// 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 errors holds the standardized error definition for gVisor.
+package errors
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
+)
+
+// Error represents a syscall errno with a descriptive message.
+type Error struct {
+	errno   errno.Errno
+	message string
+}
+
+// New creates a new *Error.
+func New(err errno.Errno, message string) *Error {
+	return &Error{
+		errno:   err,
+		message: message,
+	}
+}
+
+// Error implements error.Error.
+func (e *Error) Error() string { return e.message }
+
+// Errno returns the underlying errno.Errno value.
+func (e *Error) Errno() errno.Errno { return e.errno }
diff --git a/pkg/errors/linuxerr/BUILD b/pkg/errors/linuxerr/BUILD
new file mode 100644
index 000000000..8afc9688c
--- /dev/null
+++ b/pkg/errors/linuxerr/BUILD
@@ -0,0 +1,25 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "linuxerr",
+    srcs = ["linuxerr.go"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/abi/linux/errno",
+        "//pkg/errors",
+    ],
+)
+
+go_test(
+    name = "linuxerr_test",
+    srcs = ["linuxerr_test.go"],
+    deps = [
+        ":linuxerr",
+        "//pkg/abi/linux/errno",
+        "//pkg/errors",
+        "//pkg/syserror",
+        "@org_golang_x_sys//unix:go_default_library",
+    ],
+)
diff --git a/pkg/errors/linuxerr/linuxerr.go b/pkg/errors/linuxerr/linuxerr.go
new file mode 100644
index 000000000..23d9f9f75
--- /dev/null
+++ b/pkg/errors/linuxerr/linuxerr.go
@@ -0,0 +1,326 @@
+// 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 contains syscall error codes exported as an error interface
+// pointers. This allows for fast comparison and return operations comperable
+// to unix.Errno constants.
+package linuxerr
+
+import (
+	"fmt"
+
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
+	"gvisor.dev/gvisor/pkg/errors"
+)
+
+const maxErrno uint32 = errno.EHWPOISON + 1
+
+var (
+	EPERM   = errors.New(errno.EPERM, "operation not permitted")
+	ENOENT  = errors.New(errno.ENOENT, "no such file or directory")
+	ESRCH   = errors.New(errno.ESRCH, "no such process")
+	EINTR   = errors.New(errno.EINTR, "interrupted system call")
+	EIO     = errors.New(errno.EIO, "I/O error")
+	ENXIO   = errors.New(errno.ENXIO, "no such device or address")
+	E2BIG   = errors.New(errno.E2BIG, "argument list too long")
+	ENOEXEC = errors.New(errno.ENOEXEC, "exec format error")
+	EBADF   = errors.New(errno.EBADF, "bad file number")
+	ECHILD  = errors.New(errno.ECHILD, "no child processes")
+	EAGAIN  = errors.New(errno.EAGAIN, "try again")
+	ENOMEM  = errors.New(errno.ENOMEM, "out of memory")
+	EACCES  = errors.New(errno.EACCES, "permission denied")
+	EFAULT  = errors.New(errno.EFAULT, "bad address")
+	ENOTBLK = errors.New(errno.ENOTBLK, "block device required")
+	EBUSY   = errors.New(errno.EBUSY, "device or resource busy")
+	EEXIST  = errors.New(errno.EEXIST, "file exists")
+	EXDEV   = errors.New(errno.EXDEV, "cross-device link")
+	ENODEV  = errors.New(errno.ENODEV, "no such device")
+	ENOTDIR = errors.New(errno.ENOTDIR, "not a directory")
+	EISDIR  = errors.New(errno.EISDIR, "is a directory")
+	EINVAL  = errors.New(errno.EINVAL, "invalid argument")
+	ENFILE  = errors.New(errno.ENFILE, "file table overflow")
+	EMFILE  = errors.New(errno.EMFILE, "too many open files")
+	ENOTTY  = errors.New(errno.ENOTTY, "not a typewriter")
+	ETXTBSY = errors.New(errno.ETXTBSY, "text file busy")
+	EFBIG   = errors.New(errno.EFBIG, "file too large")
+	ENOSPC  = errors.New(errno.ENOSPC, "no space left on device")
+	ESPIPE  = errors.New(errno.ESPIPE, "illegal seek")
+	EROFS   = errors.New(errno.EROFS, "read-only file system")
+	EMLINK  = errors.New(errno.EMLINK, "too many links")
+	EPIPE   = errors.New(errno.EPIPE, "broken pipe")
+	EDOM    = errors.New(errno.EDOM, "math argument out of domain of func")
+	ERANGE  = errors.New(errno.ERANGE, "math result not representable")
+
+	// Errno values from include/uapi/asm-generic/errno.h.
+	EDEADLK         = errors.New(errno.EDEADLK, "resource deadlock would occur")
+	ENAMETOOLONG    = errors.New(errno.ENAMETOOLONG, "file name too long")
+	ENOLCK          = errors.New(errno.ENOLCK, "no record locks available")
+	ENOSYS          = errors.New(errno.ENOSYS, "invalid system call number")
+	ENOTEMPTY       = errors.New(errno.ENOTEMPTY, "directory not empty")
+	ELOOP           = errors.New(errno.ELOOP, "too many symbolic links encountered")
+	ENOMSG          = errors.New(errno.ENOMSG, "no message of desired type")
+	EIDRM           = errors.New(errno.EIDRM, "identifier removed")
+	ECHRNG          = errors.New(errno.ECHRNG, "channel number out of range")
+	EL2NSYNC        = errors.New(errno.EL2NSYNC, "level 2 not synchronized")
+	EL3HLT          = errors.New(errno.EL3HLT, "level 3 halted")
+	EL3RST          = errors.New(errno.EL3RST, "level 3 reset")
+	ELNRNG          = errors.New(errno.ELNRNG, "link number out of range")
+	EUNATCH         = errors.New(errno.EUNATCH, "protocol driver not attached")
+	ENOCSI          = errors.New(errno.ENOCSI, "no CSI structure available")
+	EL2HLT          = errors.New(errno.EL2HLT, "level 2 halted")
+	EBADE           = errors.New(errno.EBADE, "invalid exchange")
+	EBADR           = errors.New(errno.EBADR, "invalid request descriptor")
+	EXFULL          = errors.New(errno.EXFULL, "exchange full")
+	ENOANO          = errors.New(errno.ENOANO, "no anode")
+	EBADRQC         = errors.New(errno.EBADRQC, "invalid request code")
+	EBADSLT         = errors.New(errno.EBADSLT, "invalid slot")
+	EBFONT          = errors.New(errno.EBFONT, "bad font file format")
+	ENOSTR          = errors.New(errno.ENOSTR, "device not a stream")
+	ENODATA         = errors.New(errno.ENODATA, "no data available")
+	ETIME           = errors.New(errno.ETIME, "timer expired")
+	ENOSR           = errors.New(errno.ENOSR, "out of streams resources")
+	ENOPKG          = errors.New(errno.ENOPKG, "package not installed")
+	EREMOTE         = errors.New(errno.EREMOTE, "object is remote")
+	ENOLINK         = errors.New(errno.ENOLINK, "link has been severed")
+	EADV            = errors.New(errno.EADV, "advertise error")
+	ESRMNT          = errors.New(errno.ESRMNT, "srmount error")
+	ECOMM           = errors.New(errno.ECOMM, "communication error on send")
+	EPROTO          = errors.New(errno.EPROTO, "protocol error")
+	EMULTIHOP       = errors.New(errno.EMULTIHOP, "multihop attempted")
+	EDOTDOT         = errors.New(errno.EDOTDOT, "RFS specific error")
+	EBADMSG         = errors.New(errno.EBADMSG, "not a data message")
+	EOVERFLOW       = errors.New(errno.EOVERFLOW, "value too large for defined data type")
+	ENOTUNIQ        = errors.New(errno.ENOTUNIQ, "name not unique on network")
+	EBADFD          = errors.New(errno.EBADFD, "file descriptor in bad state")
+	EREMCHG         = errors.New(errno.EREMCHG, "remote address changed")
+	ELIBACC         = errors.New(errno.ELIBACC, "can not access a needed shared library")
+	ELIBBAD         = errors.New(errno.ELIBBAD, "accessing a corrupted shared library")
+	ELIBSCN         = errors.New(errno.ELIBSCN, ".lib section in a.out corrupted")
+	ELIBMAX         = errors.New(errno.ELIBMAX, "attempting to link in too many shared libraries")
+	ELIBEXEC        = errors.New(errno.ELIBEXEC, "cannot exec a shared library directly")
+	EILSEQ          = errors.New(errno.EILSEQ, "illegal byte sequence")
+	ERESTART        = errors.New(errno.ERESTART, "interrupted system call should be restarted")
+	ESTRPIPE        = errors.New(errno.ESTRPIPE, "streams pipe error")
+	EUSERS          = errors.New(errno.EUSERS, "too many users")
+	ENOTSOCK        = errors.New(errno.ENOTSOCK, "socket operation on non-socket")
+	EDESTADDRREQ    = errors.New(errno.EDESTADDRREQ, "destination address required")
+	EMSGSIZE        = errors.New(errno.EMSGSIZE, "message too long")
+	EPROTOTYPE      = errors.New(errno.EPROTOTYPE, "protocol wrong type for socket")
+	ENOPROTOOPT     = errors.New(errno.ENOPROTOOPT, "protocol not available")
+	EPROTONOSUPPORT = errors.New(errno.EPROTONOSUPPORT, "protocol not supported")
+	ESOCKTNOSUPPORT = errors.New(errno.ESOCKTNOSUPPORT, "socket type not supported")
+	EOPNOTSUPP      = errors.New(errno.EOPNOTSUPP, "operation not supported on transport endpoint")
+	EPFNOSUPPORT    = errors.New(errno.EPFNOSUPPORT, "protocol family not supported")
+	EAFNOSUPPORT    = errors.New(errno.EAFNOSUPPORT, "address family not supported by protocol")
+	EADDRINUSE      = errors.New(errno.EADDRINUSE, "address already in use")
+	EADDRNOTAVAIL   = errors.New(errno.EADDRNOTAVAIL, "cannot assign requested address")
+	ENETDOWN        = errors.New(errno.ENETDOWN, "network is down")
+	ENETUNREACH     = errors.New(errno.ENETUNREACH, "network is unreachable")
+	ENETRESET       = errors.New(errno.ENETRESET, "network dropped connection because of reset")
+	ECONNABORTED    = errors.New(errno.ECONNABORTED, "software caused connection abort")
+	ECONNRESET      = errors.New(errno.ECONNRESET, "connection reset by peer")
+	ENOBUFS         = errors.New(errno.ENOBUFS, "no buffer space available")
+	EISCONN         = errors.New(errno.EISCONN, "transport endpoint is already connected")
+	ENOTCONN        = errors.New(errno.ENOTCONN, "transport endpoint is not connected")
+	ESHUTDOWN       = errors.New(errno.ESHUTDOWN, "cannot send after transport endpoint shutdown")
+	ETOOMANYREFS    = errors.New(errno.ETOOMANYREFS, "too many references: cannot splice")
+	ETIMEDOUT       = errors.New(errno.ETIMEDOUT, "connection timed out")
+	ECONNREFUSED    = errors.New(errno.ECONNREFUSED, "connection refused")
+	EHOSTDOWN       = errors.New(errno.EHOSTDOWN, "host is down")
+	EHOSTUNREACH    = errors.New(errno.EHOSTUNREACH, "no route to host")
+	EALREADY        = errors.New(errno.EALREADY, "operation already in progress")
+	EINPROGRESS     = errors.New(errno.EINPROGRESS, "operation now in progress")
+	ESTALE          = errors.New(errno.ESTALE, "stale file handle")
+	EUCLEAN         = errors.New(errno.EUCLEAN, "structure needs cleaning")
+	ENOTNAM         = errors.New(errno.ENOTNAM, "not a XENIX named type file")
+	ENAVAIL         = errors.New(errno.ENAVAIL, "no XENIX semaphores available")
+	EISNAM          = errors.New(errno.EISNAM, "is a named type file")
+	EREMOTEIO       = errors.New(errno.EREMOTEIO, "remote I/O error")
+	EDQUOT          = errors.New(errno.EDQUOT, "quota exceeded")
+	ENOMEDIUM       = errors.New(errno.ENOMEDIUM, "no medium found")
+	EMEDIUMTYPE     = errors.New(errno.EMEDIUMTYPE, "wrong medium type")
+	ECANCELED       = errors.New(errno.ECANCELED, "operation Canceled")
+	ENOKEY          = errors.New(errno.ENOKEY, "required key not available")
+	EKEYEXPIRED     = errors.New(errno.EKEYEXPIRED, "key has expired")
+	EKEYREVOKED     = errors.New(errno.EKEYREVOKED, "key has been revoked")
+	EKEYREJECTED    = errors.New(errno.EKEYREJECTED, "key was rejected by service")
+	EOWNERDEAD      = errors.New(errno.EOWNERDEAD, "owner died")
+	ENOTRECOVERABLE = errors.New(errno.ENOTRECOVERABLE, "state not recoverable")
+	ERFKILL         = errors.New(errno.ERFKILL, "operation not possible due to RF-kill")
+	EHWPOISON       = errors.New(errno.EHWPOISON, "memory page has hardware error")
+
+	// Errors equivalent to other errors.
+	EWOULDBLOCK = EAGAIN
+	EDEADLOCK   = EDEADLK
+	ENONET      = ENOENT
+)
+
+// A nil *errors.Error denotes no error and is placed at the 0 index of
+// errorSlice. Thus, any other empty index should not be nil or a valid error.
+// This marks that index as an invalid error so any comparison to nil or a
+// valid linuxerr fails.
+var errNotValidError = errors.New(errno.Errno(maxErrno), "not a valid error")
+
+// The following errorSlice holds errors by errno for fast translation between
+// errnos (especially uint32(sycall.Errno)) and *Error.
+var errorSlice = []*errors.Error{
+	// Errno values from include/uapi/asm-generic/errno-base.h.
+	errno.NOERRNO: nil,
+	errno.EPERM:   EPERM,
+	errno.ENOENT:  ENOENT,
+	errno.ESRCH:   ESRCH,
+	errno.EINTR:   EINTR,
+	errno.EIO:     EIO,
+	errno.ENXIO:   ENXIO,
+	errno.E2BIG:   E2BIG,
+	errno.ENOEXEC: ENOEXEC,
+	errno.EBADF:   EBADF,
+	errno.ECHILD:  ECHILD,
+	errno.EAGAIN:  EAGAIN,
+	errno.ENOMEM:  ENOMEM,
+	errno.EACCES:  EACCES,
+	errno.EFAULT:  EFAULT,
+	errno.ENOTBLK: ENOTBLK,
+	errno.EBUSY:   EBUSY,
+	errno.EEXIST:  EEXIST,
+	errno.EXDEV:   EXDEV,
+	errno.ENODEV:  ENODEV,
+	errno.ENOTDIR: ENOTDIR,
+	errno.EISDIR:  EISDIR,
+	errno.EINVAL:  EINVAL,
+	errno.ENFILE:  ENFILE,
+	errno.EMFILE:  EMFILE,
+	errno.ENOTTY:  ENOTTY,
+	errno.ETXTBSY: ETXTBSY,
+	errno.EFBIG:   EFBIG,
+	errno.ENOSPC:  ENOSPC,
+	errno.ESPIPE:  ESPIPE,
+	errno.EROFS:   EROFS,
+	errno.EMLINK:  EMLINK,
+	errno.EPIPE:   EPIPE,
+	errno.EDOM:    EDOM,
+	errno.ERANGE:  ERANGE,
+
+	// Errno values from include/uapi/asm-generic/errno.h.
+	errno.EDEADLK:         EDEADLK,
+	errno.ENAMETOOLONG:    ENAMETOOLONG,
+	errno.ENOLCK:          ENOLCK,
+	errno.ENOSYS:          ENOSYS,
+	errno.ENOTEMPTY:       ENOTEMPTY,
+	errno.ELOOP:           ELOOP,
+	errno.ELOOP + 1:       errNotValidError, // No valid errno between ELOOP and ENOMSG.
+	errno.ENOMSG:          ENOMSG,
+	errno.EIDRM:           EIDRM,
+	errno.ECHRNG:          ECHRNG,
+	errno.EL2NSYNC:        EL2NSYNC,
+	errno.EL3HLT:          EL3HLT,
+	errno.EL3RST:          EL3RST,
+	errno.ELNRNG:          ELNRNG,
+	errno.EUNATCH:         EUNATCH,
+	errno.ENOCSI:          ENOCSI,
+	errno.EL2HLT:          EL2HLT,
+	errno.EBADE:           EBADE,
+	errno.EBADR:           EBADR,
+	errno.EXFULL:          EXFULL,
+	errno.ENOANO:          ENOANO,
+	errno.EBADRQC:         EBADRQC,
+	errno.EBADSLT:         EBADSLT,
+	errno.EBADSLT + 1:     errNotValidError, // No valid errno between EBADSLT and ENOPKG.
+	errno.EBFONT:          EBFONT,
+	errno.ENOSTR:          ENOSTR,
+	errno.ENODATA:         ENODATA,
+	errno.ETIME:           ETIME,
+	errno.ENOSR:           ENOSR,
+	errno.ENOSR + 1:       errNotValidError, // No valid errno betweeen ENOSR and ENOPKG.
+	errno.ENOPKG:          ENOPKG,
+	errno.EREMOTE:         EREMOTE,
+	errno.ENOLINK:         ENOLINK,
+	errno.EADV:            EADV,
+	errno.ESRMNT:          ESRMNT,
+	errno.ECOMM:           ECOMM,
+	errno.EPROTO:          EPROTO,
+	errno.EMULTIHOP:       EMULTIHOP,
+	errno.EDOTDOT:         EDOTDOT,
+	errno.EBADMSG:         EBADMSG,
+	errno.EOVERFLOW:       EOVERFLOW,
+	errno.ENOTUNIQ:        ENOTUNIQ,
+	errno.EBADFD:          EBADFD,
+	errno.EREMCHG:         EREMCHG,
+	errno.ELIBACC:         ELIBACC,
+	errno.ELIBBAD:         ELIBBAD,
+	errno.ELIBSCN:         ELIBSCN,
+	errno.ELIBMAX:         ELIBMAX,
+	errno.ELIBEXEC:        ELIBEXEC,
+	errno.EILSEQ:          EILSEQ,
+	errno.ERESTART:        ERESTART,
+	errno.ESTRPIPE:        ESTRPIPE,
+	errno.EUSERS:          EUSERS,
+	errno.ENOTSOCK:        ENOTSOCK,
+	errno.EDESTADDRREQ:    EDESTADDRREQ,
+	errno.EMSGSIZE:        EMSGSIZE,
+	errno.EPROTOTYPE:      EPROTOTYPE,
+	errno.ENOPROTOOPT:     ENOPROTOOPT,
+	errno.EPROTONOSUPPORT: EPROTONOSUPPORT,
+	errno.ESOCKTNOSUPPORT: ESOCKTNOSUPPORT,
+	errno.EOPNOTSUPP:      EOPNOTSUPP,
+	errno.EPFNOSUPPORT:    EPFNOSUPPORT,
+	errno.EAFNOSUPPORT:    EAFNOSUPPORT,
+	errno.EADDRINUSE:      EADDRINUSE,
+	errno.EADDRNOTAVAIL:   EADDRNOTAVAIL,
+	errno.ENETDOWN:        ENETDOWN,
+	errno.ENETUNREACH:     ENETUNREACH,
+	errno.ENETRESET:       ENETRESET,
+	errno.ECONNABORTED:    ECONNABORTED,
+	errno.ECONNRESET:      ECONNRESET,
+	errno.ENOBUFS:         ENOBUFS,
+	errno.EISCONN:         EISCONN,
+	errno.ENOTCONN:        ENOTCONN,
+	errno.ESHUTDOWN:       ESHUTDOWN,
+	errno.ETOOMANYREFS:    ETOOMANYREFS,
+	errno.ETIMEDOUT:       ETIMEDOUT,
+	errno.ECONNREFUSED:    ECONNREFUSED,
+	errno.EHOSTDOWN:       EHOSTDOWN,
+	errno.EHOSTUNREACH:    EHOSTUNREACH,
+	errno.EALREADY:        EALREADY,
+	errno.EINPROGRESS:     EINPROGRESS,
+	errno.ESTALE:          ESTALE,
+	errno.EUCLEAN:         EUCLEAN,
+	errno.ENOTNAM:         ENOTNAM,
+	errno.ENAVAIL:         ENAVAIL,
+	errno.EISNAM:          EISNAM,
+	errno.EREMOTEIO:       EREMOTEIO,
+	errno.EDQUOT:          EDQUOT,
+	errno.ENOMEDIUM:       ENOMEDIUM,
+	errno.EMEDIUMTYPE:     EMEDIUMTYPE,
+	errno.ECANCELED:       ECANCELED,
+	errno.ENOKEY:          ENOKEY,
+	errno.EKEYEXPIRED:     EKEYEXPIRED,
+	errno.EKEYREVOKED:     EKEYREVOKED,
+	errno.EKEYREJECTED:    EKEYREJECTED,
+	errno.EOWNERDEAD:      EOWNERDEAD,
+	errno.ENOTRECOVERABLE: ENOTRECOVERABLE,
+	errno.ERFKILL:         ERFKILL,
+	errno.EHWPOISON:       EHWPOISON,
+}
+
+// ErrorFromErrno gets an error from the list and panics if an invalid entry is requested.
+func ErrorFromErrno(e errno.Errno) *errors.Error {
+	err := errorSlice[e]
+	// Done this way because a single comparison in benchmarks is 2-3 faster
+	// than something like ( if err == nil && err > 0 ).
+	if err != errNotValidError {
+		return err
+	}
+	panic(fmt.Sprintf("invalid error requested with errno: %d", e))
+}
diff --git a/pkg/errors/linuxerr/linuxerr_test.go b/pkg/errors/linuxerr/linuxerr_test.go
new file mode 100644
index 000000000..a81dd9560
--- /dev/null
+++ b/pkg/errors/linuxerr/linuxerr_test.go
@@ -0,0 +1,245 @@
+// Copyright 2018 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 syserror_test
+
+import (
+	"errors"
+	"syscall"
+	"testing"
+
+	"golang.org/x/sys/unix"
+	"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
+
+func BenchmarkAssignUnix(b *testing.B) {
+	for i := b.N; i > 0; i-- {
+		globalError = unix.EINVAL
+	}
+}
+
+func BenchmarkAssignLinuxerr(b *testing.B) {
+	for i := b.N; i > 0; i-- {
+		globalError = linuxerr.EINVAL
+	}
+}
+
+func BenchmarkAssignSyserror(b *testing.B) {
+	for i := b.N; i > 0; i-- {
+		globalError = syserror.EINVAL
+	}
+}
+
+func BenchmarkCompareUnix(b *testing.B) {
+	globalError = unix.EAGAIN
+	j := 0
+	for i := b.N; i > 0; i-- {
+		if globalError == unix.EINVAL {
+			j++
+		}
+	}
+}
+
+func BenchmarkCompareLinuxerr(b *testing.B) {
+	globalError = linuxerr.E2BIG
+	j := 0
+	for i := b.N; i > 0; i-- {
+		if globalError == linuxerr.EINVAL {
+			j++
+		}
+	}
+}
+
+func BenchmarkCompareSyserror(b *testing.B) {
+	globalError = syserror.EAGAIN
+	j := 0
+	for i := b.N; i > 0; i-- {
+		if globalError == syserror.EINVAL {
+			j++
+		}
+	}
+}
+
+func BenchmarkSwitchUnix(b *testing.B) {
+	globalError = unix.EPERM
+	j := 0
+	for i := b.N; i > 0; i-- {
+		switch globalError {
+		case unix.EINVAL:
+			j++
+		case unix.EINTR:
+			j += 2
+		case unix.EAGAIN:
+			j += 3
+		}
+	}
+}
+
+func BenchmarkSwitchLinuxerr(b *testing.B) {
+	globalError = linuxerr.EPERM
+	j := 0
+	for i := b.N; i > 0; i-- {
+		switch globalError {
+		case linuxerr.EINVAL:
+			j++
+		case linuxerr.EINTR:
+			j += 2
+		case linuxerr.EAGAIN:
+			j += 3
+		}
+	}
+}
+
+func BenchmarkSwitchSyserror(b *testing.B) {
+	globalError = syserror.EPERM
+	j := 0
+	for i := b.N; i > 0; i-- {
+		switch globalError {
+		case syserror.EINVAL:
+			j++
+		case syserror.EINTR:
+			j += 2
+		case syserror.EAGAIN:
+			j += 3
+		}
+	}
+}
+
+func BenchmarkReturnUnix(b *testing.B) {
+	var localError error
+	f := func() error {
+		return unix.EINVAL
+	}
+	for i := b.N; i > 0; i-- {
+		localError = f()
+	}
+	if localError != nil {
+		return
+	}
+}
+
+func BenchmarkReturnLinuxerr(b *testing.B) {
+	var localError error
+	f := func() error {
+		return linuxerr.EINVAL
+	}
+	for i := b.N; i > 0; i-- {
+		localError = f()
+	}
+	if localError != nil {
+		return
+	}
+}
+
+func BenchmarkConvertUnixLinuxerr(b *testing.B) {
+	var localError error
+	for i := b.N; i > 0; i-- {
+		localError = linuxerr.ErrorFromErrno(errno.Errno(unix.EINVAL))
+	}
+	if localError != nil {
+		return
+	}
+}
+
+func BenchmarkConvertUnixLinuxerrZero(b *testing.B) {
+	var localError error
+	for i := b.N; i > 0; i-- {
+		localError = linuxerr.ErrorFromErrno(errno.Errno(0))
+	}
+	if localError != nil {
+		return
+	}
+}
+
+type translationTestTable struct {
+	fn                  string
+	errIn               error
+	syscallErrorIn      unix.Errno
+	expectedBool        bool
+	expectedTranslation unix.Errno
+}
+
+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},
+	}
+	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)
+			} 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)
+			}
+		default:
+			t.Fatalf("Unknown function %v", tt.fn)
+		}
+	}
+}
+
+func TestSyscallErrnoToErrors(t *testing.T) {
+	for _, tc := range []struct {
+		errno syscall.Errno
+		err   *gErrors.Error
+	}{
+		{errno: syscall.EACCES, err: linuxerr.EACCES},
+		{errno: syscall.EAGAIN, err: linuxerr.EAGAIN},
+		{errno: syscall.EBADF, err: linuxerr.EBADF},
+		{errno: syscall.EBUSY, err: linuxerr.EBUSY},
+		{errno: syscall.EDOM, err: linuxerr.EDOM},
+		{errno: syscall.EEXIST, err: linuxerr.EEXIST},
+		{errno: syscall.EFAULT, err: linuxerr.EFAULT},
+		{errno: syscall.EFBIG, err: linuxerr.EFBIG},
+		{errno: syscall.EINTR, err: linuxerr.EINTR},
+		{errno: syscall.EINVAL, err: linuxerr.EINVAL},
+		{errno: syscall.EIO, err: linuxerr.EIO},
+		{errno: syscall.ENOTDIR, err: linuxerr.ENOTDIR},
+		{errno: syscall.ENOTTY, err: linuxerr.ENOTTY},
+		{errno: syscall.EPERM, err: linuxerr.EPERM},
+		{errno: syscall.EPIPE, err: linuxerr.EPIPE},
+		{errno: syscall.ESPIPE, err: linuxerr.ESPIPE},
+		{errno: syscall.EWOULDBLOCK, err: linuxerr.EAGAIN},
+	} {
+		t.Run(tc.errno.Error(), func(t *testing.T) {
+			e := linuxerr.ErrorFromErrno(errno.Errno(tc.errno))
+			if e != tc.err {
+				t.Fatalf("Mismatch errors: want: %+v (%d) got: %+v %d", tc.err, tc.err.Errno(), e, e.Errno())
+			}
+		})
+	}
+}