[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

8 files changed, 12 insertions, 5 deletions

diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index 188c0ebff..a82d641da 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -218,6 +218,7 @@ go_library(
         ":uncaught_signal_go_proto",
         "//pkg/abi",
         "//pkg/abi/linux",
+        "//pkg/abi/linux/errno",
         "//pkg/amutex",
         "//pkg/bits",
         "//pkg/bpf",
diff --git a/pkg/sentry/kernel/task_image.go b/pkg/sentry/kernel/task_image.go
index bd5543d4e..c132c27ef 100644
--- a/pkg/sentry/kernel/task_image.go
+++ b/pkg/sentry/kernel/task_image.go
@@ -17,7 +17,7 @@ package kernel
 import (
 	"fmt"
 
-	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
@@ -27,7 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/syserr"
 )
 
-var errNoSyscalls = syserr.New("no syscall table found", linux.ENOEXEC)
+var errNoSyscalls = syserr.New("no syscall table found", errno.ENOEXEC)
 
 // Auxmap contains miscellaneous data for the task.
 type Auxmap map[string]interface{}
diff --git a/pkg/sentry/loader/BUILD b/pkg/sentry/loader/BUILD
index 4c65215fa..80f862628 100644
--- a/pkg/sentry/loader/BUILD
+++ b/pkg/sentry/loader/BUILD
@@ -17,6 +17,7 @@ go_library(
     deps = [
         "//pkg/abi",
         "//pkg/abi/linux",
+        "//pkg/abi/linux/errno",
         "//pkg/context",
         "//pkg/cpuid",
         "//pkg/hostarch",
diff --git a/pkg/sentry/loader/loader.go b/pkg/sentry/loader/loader.go
index 47e3775a3..8240173ae 100644
--- a/pkg/sentry/loader/loader.go
+++ b/pkg/sentry/loader/loader.go
@@ -23,6 +23,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi"
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/cpuid"
 	"gvisor.dev/gvisor/pkg/hostarch"
@@ -237,7 +238,7 @@ func Load(ctx context.Context, args LoadArgs, extraAuxv []arch.AuxEntry, vdso *V
 	// loaded.end is available for its use.
 	e, ok := loaded.end.RoundUp()
 	if !ok {
-		return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("brk overflows: %#x", loaded.end), linux.ENOEXEC)
+		return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("brk overflows: %#x", loaded.end), errno.ENOEXEC)
 	}
 	args.MemoryManager.BrkSetup(ctx, e)
 
diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD
index 64cd263da..6b83698ad 100644
--- a/pkg/sentry/socket/netlink/BUILD
+++ b/pkg/sentry/socket/netlink/BUILD
@@ -14,6 +14,7 @@ go_library(
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/abi/linux/errno",
         "//pkg/bits",
         "//pkg/context",
         "//pkg/hostarch",
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index 280563d09..c9f784cf4 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -20,6 +20,7 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/marshal"
@@ -56,7 +57,7 @@ const (
 	maxSendBufferSize = 4 << 20 // 4MB
 )
 
-var errNoFilter = syserr.New("no filter attached", linux.ENOENT)
+var errNoFilter = syserr.New("no filter attached", errno.ENOENT)
 
 // netlinkSocketDevice is the netlink socket virtual device.
 var netlinkSocketDevice = device.NewAnonDevice()
diff --git a/pkg/sentry/socket/netstack/BUILD b/pkg/sentry/socket/netstack/BUILD
index 9561b7c25..96c425619 100644
--- a/pkg/sentry/socket/netstack/BUILD
+++ b/pkg/sentry/socket/netstack/BUILD
@@ -19,6 +19,7 @@ go_library(
     ],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/abi/linux/errno",
         "//pkg/context",
         "//pkg/hostarch",
         "//pkg/log",
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 11ba80497..66d0fcb47 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -36,6 +36,7 @@ import (
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
@@ -289,7 +290,7 @@ const DefaultTTL = 64
 
 const sizeOfInt32 int = 4
 
-var errStackType = syserr.New("expected but did not receive a netstack.Stack", linux.EINVAL)
+var errStackType = syserr.New("expected but did not receive a netstack.Stack", errno.EINVAL)
 
 // commonEndpoint represents the intersection of a tcpip.Endpoint and a
 // transport.Endpoint.