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=== Description (from pull-request) ===
Signed-off-by: Stéphane Graber <stgra...@ubuntu.com>
From b233e6a315b064de23354846efd578886592a37d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgra...@ubuntu.com>
Date: Tue, 13 Mar 2018 12:22:36 -0400
Subject: [PATCH] Improve /etc/hosts generator
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Stéphane Graber <stgra...@ubuntu.com>
---
distrobuilder/main.go | 8 ++++++-
generators/hostname.go | 13 ++++++++++++
generators/hostname_test.go | 2 ++
generators/hosts.go | 52 ++++++++++++++++++++++++++++++++-------------
generators/hosts_test.go | 8 +++----
5 files changed, 63 insertions(+), 20 deletions(-)
diff --git a/distrobuilder/main.go b/distrobuilder/main.go
index f623027..cae2fa8 100644
--- a/distrobuilder/main.go
+++ b/distrobuilder/main.go
@@ -20,11 +20,17 @@ __attribute__((constructor)) void init(void) {
}
// Unshare a new mntns so our mounts don't leak
- if (unshare(CLONE_NEWNS | CLONE_NEWPID) < 0) {
+ if (unshare(CLONE_NEWNS | CLONE_NEWPID | CLONE_NEWUTS) < 0) {
fprintf(stderr, "Failed to unshare namespaces: %s\n",
strerror(errno));
_exit(1);
}
+ // Hardcode the hostname to "distrobuilder"
+ if (sethostname("distrobuilder", 13) < 0) {
+ fprintf(stderr, "Failed to set hostname: %s\n",
strerror(errno));
+ _exit(1);
+ }
+
// Prevent mount propagation back to initial namespace
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL) < 0) {
fprintf(stderr, "Failed to mark / private: %s\n",
strerror(errno));
diff --git a/generators/hostname.go b/generators/hostname.go
index a227532..9ec4949 100644
--- a/generators/hostname.go
+++ b/generators/hostname.go
@@ -5,6 +5,7 @@ import (
"os"
"path/filepath"
+ lxd "github.com/lxc/lxd/shared"
"github.com/lxc/lxd/shared/api"
"github.com/lxc/distrobuilder/image"
@@ -17,6 +18,12 @@ type HostnameGenerator struct{}
// RunLXC creates a hostname template.
func (g HostnameGenerator) RunLXC(cacheDir, sourceDir string, img
*image.LXCImage,
defFile shared.DefinitionFile) error {
+
+ // Skip if the file doesn't exist
+ if !lxd.PathExists(filepath.Join(sourceDir, defFile.Path)) {
+ return nil
+ }
+
// Store original file
err := StoreFile(cacheDir, sourceDir, defFile.Path)
if err != nil {
@@ -43,6 +50,12 @@ func (g HostnameGenerator) RunLXC(cacheDir, sourceDir
string, img *image.LXCImag
// RunLXD creates a hostname template.
func (g HostnameGenerator) RunLXD(cacheDir, sourceDir string, img
*image.LXDImage,
defFile shared.DefinitionFile) error {
+
+ // Skip if the file doesn't exist
+ if !lxd.PathExists(filepath.Join(sourceDir, defFile.Path)) {
+ return nil
+ }
+
templateDir := filepath.Join(cacheDir, "templates")
err := os.MkdirAll(templateDir, 0755)
diff --git a/generators/hostname_test.go b/generators/hostname_test.go
index 446ae36..fc59c66 100644
--- a/generators/hostname_test.go
+++ b/generators/hostname_test.go
@@ -76,6 +76,8 @@ func TestHostnameGeneratorRunLXD(t *testing.T) {
t.Fatalf("Unexpected error: %s", err)
}
+ createTestFile(t, filepath.Join(cacheDir, "rootfs", "etc", "hostname"),
"hostname")
+
err = generator.RunLXD(cacheDir, rootfsDir, image,
shared.DefinitionFile{Path: "/etc/hostname"})
if err != nil {
diff --git a/generators/hosts.go b/generators/hosts.go
index 3cdc4c7..7d5d26e 100644
--- a/generators/hosts.go
+++ b/generators/hosts.go
@@ -1,12 +1,14 @@
package generators
import (
- "io"
+ "io/ioutil"
"os"
"path/filepath"
+ "strings"
"github.com/lxc/distrobuilder/image"
"github.com/lxc/distrobuilder/shared"
+ lxd "github.com/lxc/lxd/shared"
"github.com/lxc/lxd/shared/api"
)
@@ -16,21 +18,37 @@ type HostsGenerator struct{}
// RunLXC creates a LXC specific entry in the hosts file.
func (g HostsGenerator) RunLXC(cacheDir, sourceDir string, img *image.LXCImage,
defFile shared.DefinitionFile) error {
+
+ // Skip if the file doesn't exist
+ if !lxd.PathExists(filepath.Join(sourceDir, defFile.Path)) {
+ return nil
+ }
+
// Store original file
err := StoreFile(cacheDir, sourceDir, defFile.Path)
if err != nil {
return err
}
- file, err := os.OpenFile(filepath.Join(sourceDir, defFile.Path),
- os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+ // Read the current content
+ content, err := ioutil.ReadFile(filepath.Join(sourceDir, defFile.Path))
if err != nil {
return err
}
- defer file.Close()
- // Append hosts entry
- file.WriteString("127.0.0.1\tLXC_NAME\n")
+ // Replace hostname with placeholder
+ content = []byte(strings.Replace(string(content), "distrobuilder",
"LXC_NAME", -1))
+
+ // Add a new line if needed
+ if !strings.Contains(string(content), "LXC_NAME") {
+ content = append([]byte("127.0.1.1\tLXC_NAME\n"), content...)
+ }
+
+ // Overwrite the file
+ err = ioutil.WriteFile(filepath.Join(sourceDir, defFile.Path), content,
0644)
+ if err != nil {
+ return err
+ }
// Add hostname path to LXC's templates file
return img.AddTemplate(defFile.Path)
@@ -39,6 +57,12 @@ func (g HostsGenerator) RunLXC(cacheDir, sourceDir string,
img *image.LXCImage,
// RunLXD creates a hosts template.
func (g HostsGenerator) RunLXD(cacheDir, sourceDir string, img *image.LXDImage,
defFile shared.DefinitionFile) error {
+
+ // Skip if the file doesn't exist
+ if !lxd.PathExists(filepath.Join(sourceDir, defFile.Path)) {
+ return nil
+ }
+
templateDir := filepath.Join(cacheDir, "templates")
// Create templates path
@@ -47,22 +71,20 @@ func (g HostsGenerator) RunLXD(cacheDir, sourceDir string,
img *image.LXDImage,
return err
}
- // Create hosts template
- file, err := os.Create(filepath.Join(templateDir, "hosts.tpl"))
+ // Read the current content
+ content, err := ioutil.ReadFile(filepath.Join(sourceDir, defFile.Path))
if err != nil {
return err
}
- defer file.Close()
- hostsFile, err := os.Open(filepath.Join(sourceDir, defFile.Path))
+ // Replace hostname with placeholder
+ content = []byte(strings.Replace(string(content), "distrobuilder", "{{
container.name }}", -1))
+
+ // Write the template
+ err = ioutil.WriteFile(filepath.Join(templateDir, "hosts.tpl"),
content, 0644)
if err != nil {
return err
}
- defer hostsFile.Close()
-
- // Copy old content, and append LXD specific entry
- io.Copy(file, hostsFile)
- file.WriteString("127.0.0.1\t{{ container.name }}\n")
img.Metadata.Templates[defFile.Path] = &api.ImageMetadataTemplate{
Template: "hosts.tpl",
diff --git a/generators/hosts_test.go b/generators/hosts_test.go
index 318243f..e848be3 100644
--- a/generators/hosts_test.go
+++ b/generators/hosts_test.go
@@ -34,7 +34,7 @@ func TestHostsGeneratorRunLXC(t *testing.T) {
}
createTestFile(t, filepath.Join(cacheDir, "rootfs", "etc", "hosts"),
- "127.0.0.1\tlocalhost\n")
+ "127.0.0.1\tlocalhost\n127.0.0.1\tdistrobuilder\n")
err = generator.RunLXC(cacheDir, rootfsDir, image,
shared.DefinitionFile{Path: "/etc/hosts"})
@@ -43,7 +43,7 @@ func TestHostsGeneratorRunLXC(t *testing.T) {
}
validateTestFile(t, filepath.Join(cacheDir, "tmp", "etc", "hosts"),
- "127.0.0.1\tlocalhost\n")
+ "127.0.0.1\tlocalhost\n127.0.0.1\tdistrobuilder\n")
validateTestFile(t, filepath.Join(cacheDir, "rootfs", "etc", "hosts"),
"127.0.0.1\tlocalhost\n127.0.0.1\tLXC_NAME\n")
@@ -53,7 +53,7 @@ func TestHostsGeneratorRunLXC(t *testing.T) {
}
validateTestFile(t, filepath.Join(cacheDir, "rootfs", "etc", "hosts"),
- "127.0.0.1\tlocalhost\n")
+ "127.0.0.1\tlocalhost\n127.0.0.1\tdistrobuilder\n")
}
func TestHostsGeneratorRunLXD(t *testing.T) {
@@ -81,7 +81,7 @@ func TestHostsGeneratorRunLXD(t *testing.T) {
}
createTestFile(t, filepath.Join(cacheDir, "rootfs", "etc", "hosts"),
- "127.0.0.1\tlocalhost\n")
+ "127.0.0.1\tlocalhost\n127.0.0.1\tdistrobuilder\n")
err = generator.RunLXD(cacheDir, rootfsDir, image,
shared.DefinitionFile{Path: "/etc/hosts"})
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