mirror of
https://github.com/moby/moby.git
synced 2026-01-11 10:41:43 +00:00
07e2a782c7
When attempting to read a (malformed) resolv.conf with a very long line,
a obscure error would be produced that didn't provide much context to
identify the problem;
Handler for POST /v1.51/containers/mariadb11/start returned error: bufio.Scanner: token too long
This patch adds some additional error-handling to detect this situation,
and includes the filename of the resolv.conf to help the user locating
the file that failed to be parsed.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
601 lines
16 KiB
Go
601 lines
16 KiB
Go
package resolvconf
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import (
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"bufio"
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"bytes"
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"io/fs"
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"net/netip"
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"os"
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"path/filepath"
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"runtime"
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"strings"
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"testing"
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"github.com/google/go-cmp/cmp/cmpopts"
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"github.com/moby/moby/v2/internal/sliceutil"
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"gotest.tools/v3/assert"
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is "gotest.tools/v3/assert/cmp"
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"gotest.tools/v3/golden"
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)
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func TestRCOption(t *testing.T) {
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testcases := []struct {
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name string
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options string
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search string
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expFound bool
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expValue string
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}{
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{
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name: "Empty options",
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options: "",
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search: "ndots",
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},
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{
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name: "Not found",
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options: "ndots:0 edns0",
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search: "trust-ad",
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},
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{
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name: "Found with value",
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options: "ndots:0 edns0",
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search: "ndots",
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expFound: true,
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expValue: "0",
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},
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{
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name: "Found without value",
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options: "ndots:0 edns0",
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search: "edns0",
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expFound: true,
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expValue: "",
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},
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{
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name: "Found last value",
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options: "ndots:0 edns0 ndots:1",
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search: "ndots",
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expFound: true,
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expValue: "1",
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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rc, err := Parse(bytes.NewBufferString("options "+tc.options), "")
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assert.NilError(t, err)
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value, found := rc.Option(tc.search)
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assert.Check(t, is.Equal(found, tc.expFound))
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assert.Check(t, is.Equal(value, tc.expValue))
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})
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}
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}
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func TestRCWrite(t *testing.T) {
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testcases := []struct {
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name string
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fileName string
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perm os.FileMode
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hashFileName string
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modify bool
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expUserModified bool
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}{
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{
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name: "Write with hash",
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fileName: "testfile",
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hashFileName: "testfile.hash",
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},
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{
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name: "Write with hash and modify",
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fileName: "testfile",
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hashFileName: "testfile.hash",
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modify: true,
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expUserModified: true,
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},
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{
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name: "Write without hash and modify",
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fileName: "testfile",
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modify: true,
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expUserModified: false,
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},
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{
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name: "Write perm",
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fileName: "testfile",
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perm: 0o640,
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},
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}
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rc, err := Parse(bytes.NewBufferString("nameserver 1.2.3.4"), "")
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assert.NilError(t, err)
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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tc := tc
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d := t.TempDir()
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path := filepath.Join(d, tc.fileName)
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var hashPath string
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if tc.hashFileName != "" {
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hashPath = filepath.Join(d, tc.hashFileName)
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}
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if tc.perm == 0 {
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tc.perm = 0o644
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}
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err := rc.WriteFile(path, hashPath, tc.perm)
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assert.NilError(t, err)
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fi, err := os.Stat(path)
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assert.NilError(t, err)
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// Windows files won't have the expected perms.
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if runtime.GOOS != "windows" {
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assert.Check(t, is.Equal(fi.Mode(), tc.perm))
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}
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if tc.modify {
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err := os.WriteFile(path, []byte("modified"), 0o644)
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assert.NilError(t, err)
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}
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um, err := UserModified(path, hashPath)
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assert.NilError(t, err)
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assert.Check(t, is.Equal(um, tc.expUserModified))
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})
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}
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}
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var (
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a2s = sliceutil.Mapper(netip.Addr.String)
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s2a = sliceutil.Mapper(netip.MustParseAddr)
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)
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// Test that a resolv.conf file can be modified using OverrideXXX() methods
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// to modify nameservers/search/options directives, and tha options can be
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// added via AddOption().
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func TestRCModify(t *testing.T) {
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testcases := []struct {
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name string
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inputNS []string
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inputSearch []string
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inputOptions []string
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noOverrides bool // Whether to apply overrides (empty lists are valid overrides).
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overrideNS []string
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overrideSearch []string
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overrideOptions []string
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addOption string
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}{
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{
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name: "No content no overrides",
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inputNS: []string{},
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},
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{
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name: "No overrides",
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noOverrides: true,
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inputNS: []string{"1.2.3.4"},
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inputSearch: []string{"invalid"},
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inputOptions: []string{"ndots:0"},
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},
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{
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name: "Empty overrides",
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inputNS: []string{"1.2.3.4"},
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inputSearch: []string{"invalid"},
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inputOptions: []string{"ndots:0"},
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},
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{
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name: "Overrides",
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inputNS: []string{"1.2.3.4"},
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inputSearch: []string{"invalid"},
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inputOptions: []string{"ndots:0"},
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overrideNS: []string{"2.3.4.5", "fdba:acdd:587c::53"},
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overrideSearch: []string{"com", "invalid", "example"},
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overrideOptions: []string{"ndots:1", "edns0", "trust-ad"},
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},
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{
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name: "Add option no overrides",
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noOverrides: true,
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inputNS: []string{"1.2.3.4"},
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inputSearch: []string{"invalid"},
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inputOptions: []string{"ndots:0"},
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addOption: "attempts:3",
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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tc := tc
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var input strings.Builder
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if len(tc.inputNS) != 0 {
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for _, ns := range tc.inputNS {
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input.WriteString("nameserver " + ns + "\n")
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}
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}
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if len(tc.inputSearch) != 0 {
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input.WriteString("search " + strings.Join(tc.inputSearch, " ") + "\n")
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}
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if len(tc.inputOptions) != 0 {
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input.WriteString("options " + strings.Join(tc.inputOptions, " ") + "\n")
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}
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rc, err := Parse(bytes.NewBufferString(input.String()), "")
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assert.NilError(t, err)
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assert.Check(t, is.DeepEqual(a2s(rc.NameServers()), tc.inputNS, cmpopts.EquateEmpty()))
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assert.Check(t, is.DeepEqual(rc.Search(), tc.inputSearch))
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assert.Check(t, is.DeepEqual(rc.Options(), tc.inputOptions))
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if !tc.noOverrides {
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overrideNS := s2a(tc.overrideNS)
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rc.OverrideNameServers(overrideNS)
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rc.OverrideSearch(tc.overrideSearch)
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rc.OverrideOptions(tc.overrideOptions)
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assert.Check(t, is.DeepEqual(rc.NameServers(), overrideNS, cmpopts.EquateEmpty(), cmpopts.EquateComparable(netip.Addr{})))
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assert.Check(t, is.DeepEqual(rc.Search(), tc.overrideSearch, cmpopts.EquateEmpty()))
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assert.Check(t, is.DeepEqual(rc.Options(), tc.overrideOptions, cmpopts.EquateEmpty()))
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}
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if tc.addOption != "" {
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options := rc.Options()
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rc.AddOption(tc.addOption)
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assert.Check(t, is.DeepEqual(rc.Options(), append(options, tc.addOption), cmpopts.EquateEmpty()))
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}
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content, err := rc.Generate(true)
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assert.NilError(t, err)
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assert.Check(t, golden.String(string(content), t.Name()+".golden"))
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})
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}
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}
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func TestRCTransformForLegacyNw(t *testing.T) {
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testcases := []struct {
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name string
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input string
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ipv6 bool
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overrideNS []string
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}{
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{
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name: "Routable IPv4 only",
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input: "nameserver 10.0.0.1",
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},
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{
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name: "Routable IPv4 and IPv6, ipv6 enabled",
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input: "nameserver 10.0.0.1\nnameserver fdb6:b8fe:b528::1",
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ipv6: true,
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},
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{
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name: "Routable IPv4 and IPv6, ipv6 disabled",
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input: "nameserver 10.0.0.1\nnameserver fdb6:b8fe:b528::1",
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ipv6: false,
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},
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{
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name: "IPv4 localhost, ipv6 disabled",
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input: "nameserver 127.0.0.53",
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ipv6: false,
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},
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{
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name: "IPv4 localhost, ipv6 enabled",
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input: "nameserver 127.0.0.53",
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ipv6: true,
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},
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{
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name: "IPv4 and IPv6 localhost, ipv6 disabled",
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input: "nameserver 127.0.0.53\nnameserver ::1",
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ipv6: false,
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},
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{
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name: "IPv4 and IPv6 localhost, ipv6 enabled",
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input: "nameserver 127.0.0.53\nnameserver ::1",
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ipv6: true,
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},
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{
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name: "IPv4 localhost, IPv6 routeable, ipv6 enabled",
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input: "nameserver 127.0.0.53\nnameserver fd3e:2d1a:1f5a::1",
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ipv6: true,
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},
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{
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name: "IPv4 localhost, IPv6 routeable, ipv6 disabled",
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input: "nameserver 127.0.0.53\nnameserver fd3e:2d1a:1f5a::1",
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ipv6: false,
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},
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{
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name: "Override nameservers",
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input: "nameserver 127.0.0.53",
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overrideNS: []string{"127.0.0.1", "::1"},
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ipv6: false,
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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tc := tc
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rc, err := Parse(bytes.NewBufferString(tc.input), "/etc/resolv.conf")
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assert.NilError(t, err)
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if tc.overrideNS != nil {
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rc.OverrideNameServers(s2a(tc.overrideNS))
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}
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rc.TransformForLegacyNw(tc.ipv6)
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content, err := rc.Generate(true)
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assert.NilError(t, err)
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assert.Check(t, golden.String(string(content), t.Name()+".golden"))
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})
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}
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}
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func TestRCTransformForIntNS(t *testing.T) {
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mke := func(addr string, hostLoopback bool) ExtDNSEntry {
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return ExtDNSEntry{
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Addr: netip.MustParseAddr(addr),
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HostLoopback: hostLoopback,
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}
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}
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testcases := []struct {
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name string
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input string
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intNameServer string
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overrideNS []string
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overrideOptions []string
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reqdOptions []string
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expExtServers []ExtDNSEntry
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expErr string
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}{
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{
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name: "IPv4 only",
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input: "nameserver 10.0.0.1",
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expExtServers: []ExtDNSEntry{mke("10.0.0.1", true)},
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},
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{
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name: "IPv4 and IPv6, ipv6 enabled",
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input: "nameserver 10.0.0.1\nnameserver fdb6:b8fe:b528::1",
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expExtServers: []ExtDNSEntry{
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mke("10.0.0.1", true),
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mke("fdb6:b8fe:b528::1", true),
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},
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},
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{
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name: "IPv4 localhost",
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input: "nameserver 127.0.0.53",
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", true)},
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},
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{
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// Overriding the nameserver with a localhost address means use the container's
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// loopback interface, not the host's.
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name: "IPv4 localhost override",
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input: "nameserver 10.0.0.1",
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overrideNS: []string{"127.0.0.53"},
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", false)},
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},
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{
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name: "IPv6 only",
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input: "nameserver fd14:6e0e:f855::1",
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expExtServers: []ExtDNSEntry{mke("fd14:6e0e:f855::1", true)},
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},
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{
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name: "IPv4 and IPv6 localhost",
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input: "nameserver 127.0.0.53\nnameserver ::1",
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expExtServers: []ExtDNSEntry{
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mke("127.0.0.53", true),
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mke("::1", true),
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},
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},
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{
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name: "ndots present and required",
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input: "nameserver 127.0.0.53\noptions ndots:1",
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reqdOptions: []string{"ndots:0"},
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", true)},
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},
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{
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name: "ndots missing but required",
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input: "nameserver 127.0.0.53",
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reqdOptions: []string{"ndots:0"},
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", true)},
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},
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{
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name: "ndots host, override and required",
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input: "nameserver 127.0.0.53",
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reqdOptions: []string{"ndots:0"},
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overrideOptions: []string{"ndots:2"},
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", true)},
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},
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{
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name: "Extra required options",
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input: "nameserver 127.0.0.53\noptions trust-ad",
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reqdOptions: []string{"ndots:0", "attempts:3", "edns0", "trust-ad"},
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expExtServers: []ExtDNSEntry{mke("127.0.0.53", true)},
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},
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{
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name: "No config",
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input: "",
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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tc := tc
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rc, err := Parse(bytes.NewBufferString(tc.input), "/etc/resolv.conf")
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assert.NilError(t, err)
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if tc.intNameServer == "" {
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tc.intNameServer = "127.0.0.11"
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}
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if len(tc.overrideNS) > 0 {
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rc.OverrideNameServers(s2a(tc.overrideNS))
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}
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if len(tc.overrideOptions) > 0 {
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rc.OverrideOptions(tc.overrideOptions)
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}
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intNS := netip.MustParseAddr(tc.intNameServer)
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extNameServers, err := rc.TransformForIntNS(intNS, tc.reqdOptions)
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if tc.expErr != "" {
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assert.Check(t, is.ErrorContains(err, tc.expErr))
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return
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}
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assert.NilError(t, err)
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content, err := rc.Generate(true)
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assert.NilError(t, err)
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assert.Check(t, golden.String(string(content), t.Name()+".golden"))
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assert.Check(t, is.DeepEqual(extNameServers, tc.expExtServers,
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cmpopts.EquateComparable(netip.Addr{})))
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})
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}
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}
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// Check that invalid ndots options in the host's file are ignored, unless
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// starting the internal resolver (which requires an ndots option), in which
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// case invalid ndots should be replaced.
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func TestRCTransformForIntNSInvalidNdots(t *testing.T) {
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testcases := []struct {
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name string
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options string
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reqdOptions []string
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expVal string
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expOptions []string
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expNDotsFrom string
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}{
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{
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name: "Negative value",
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options: "options ndots:-1",
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expOptions: []string{"ndots:-1"},
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expVal: "-1",
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expNDotsFrom: "host",
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},
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{
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name: "Invalid values with reqd ndots",
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options: "options ndots:-1 foo:bar ndots ndots:",
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reqdOptions: []string{"ndots:2"},
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expVal: "2",
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expNDotsFrom: "internal",
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expOptions: []string{"foo:bar", "ndots:2"},
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},
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{
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name: "Valid value with reqd ndots",
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options: "options ndots:1 foo:bar ndots ndots:",
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reqdOptions: []string{"ndots:2"},
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expVal: "1",
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expNDotsFrom: "host",
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expOptions: []string{"ndots:1", "foo:bar"},
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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content := "nameserver 8.8.8.8\n" + tc.options
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rc, err := Parse(bytes.NewBufferString(content), "/etc/resolv.conf")
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assert.NilError(t, err)
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_, err = rc.TransformForIntNS(netip.MustParseAddr("127.0.0.11"), tc.reqdOptions)
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assert.NilError(t, err)
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val, found := rc.Option("ndots")
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assert.Check(t, is.Equal(found, true))
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assert.Check(t, is.Equal(val, tc.expVal))
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assert.Check(t, is.Equal(rc.md.NDotsFrom, tc.expNDotsFrom))
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assert.Check(t, is.DeepEqual(rc.options, tc.expOptions))
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})
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}
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}
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func TestRCRead(t *testing.T) {
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d := t.TempDir()
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path := filepath.Join(d, "resolv.conf")
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|
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// Try to read a nonexistent file, equivalent to an empty file.
|
|
_, err := Load(path)
|
|
assert.Check(t, is.ErrorIs(err, fs.ErrNotExist))
|
|
|
|
err = os.WriteFile(path, []byte("options edns0"), 0o644)
|
|
assert.NilError(t, err)
|
|
|
|
// Read that file in the constructor.
|
|
rc, err := Load(path)
|
|
assert.NilError(t, err)
|
|
assert.Check(t, is.DeepEqual(rc.Options(), []string{"edns0"}))
|
|
|
|
// Pass in an os.File, check the path is extracted.
|
|
file, err := os.Open(path)
|
|
assert.NilError(t, err)
|
|
rc, err = Parse(file, "")
|
|
_ = file.Close()
|
|
assert.NilError(t, err)
|
|
assert.Check(t, is.Equal(rc.md.SourcePath, path))
|
|
}
|
|
|
|
func TestRCInvalidNS(t *testing.T) {
|
|
// A resolv.conf with an invalid nameserver address.
|
|
rc, err := Parse(bytes.NewBufferString("nameserver 1.2.3.4.5"), "")
|
|
assert.NilError(t, err)
|
|
|
|
content, err := rc.Generate(true)
|
|
assert.NilError(t, err)
|
|
assert.Check(t, golden.String(string(content), t.Name()+".golden"))
|
|
}
|
|
|
|
func TestRCSetHeader(t *testing.T) {
|
|
rc, err := Parse(bytes.NewBufferString("nameserver 127.0.0.53"), "/etc/resolv.conf")
|
|
assert.NilError(t, err)
|
|
|
|
rc.SetHeader("# This is a comment.")
|
|
|
|
content, err := rc.Generate(true)
|
|
assert.NilError(t, err)
|
|
assert.Check(t, golden.String(string(content), t.Name()+".golden"))
|
|
}
|
|
|
|
func TestRCUnknownDirectives(t *testing.T) {
|
|
const input = `
|
|
something unexpected
|
|
nameserver 127.0.0.53
|
|
options ndots:1
|
|
unrecognised thing
|
|
`
|
|
rc, err := Parse(bytes.NewBufferString(input), "/etc/resolv.conf")
|
|
assert.NilError(t, err)
|
|
|
|
content, err := rc.Generate(true)
|
|
assert.NilError(t, err)
|
|
assert.Check(t, golden.String(string(content), t.Name()+".golden"))
|
|
}
|
|
|
|
// TestRCParseErrors tests that attempting to read a resolv.conf with a
|
|
// very long line produces a useful error.
|
|
// see https://github.com/moby/moby/issues/51679#issuecomment-3714403300
|
|
func TestRCParseErrors(t *testing.T) {
|
|
input := strings.Repeat("a", bufio.MaxScanTokenSize+1) + "\n"
|
|
|
|
_, err := Parse(bytes.NewBufferString(input), "/etc/resolv.conf")
|
|
assert.Error(t, err, `failed to parse resolv.conf from /etc/resolv.conf: line too long (exceeds 65536)`)
|
|
}
|
|
|
|
func BenchmarkGenerate(b *testing.B) {
|
|
rc := &ResolvConf{
|
|
nameServers: []netip.Addr{
|
|
netip.MustParseAddr("8.8.8.8"),
|
|
netip.MustParseAddr("1.1.1.1"),
|
|
},
|
|
search: []string{"example.com", "svc.local"},
|
|
options: []string{"ndots:1", "ndots:2", "ndots:3"},
|
|
other: []string{"something", "something else", "something else"},
|
|
md: metadata{
|
|
Header: `# Generated by Docker Engine.
|
|
# This file can be edited; Docker Engine will not make further changes once it
|
|
# has been modified.`,
|
|
NSOverride: true,
|
|
SearchOverride: true,
|
|
OptionsOverride: true,
|
|
NDotsFrom: "host",
|
|
ExtNameServers: []ExtDNSEntry{
|
|
{Addr: netip.MustParseAddr("127.0.0.53"), HostLoopback: true},
|
|
{Addr: netip.MustParseAddr("2.2.2.2"), HostLoopback: false},
|
|
},
|
|
InvalidNSs: []string{"256.256.256.256"},
|
|
Warnings: []string{"bad nameserver ignored"},
|
|
},
|
|
}
|
|
|
|
b.ReportAllocs()
|
|
for b.Loop() {
|
|
_, err := rc.Generate(true)
|
|
if err != nil {
|
|
b.Fatal(err)
|
|
}
|
|
}
|
|
}
|