summaryrefslogtreecommitdiffhomepage
path: root/runsc/fsgofer
diff options
context:
space:
mode:
authorFabricio Voznika <fvoznika@google.com>2018-05-10 12:37:46 -0700
committerShentubot <shentubot@google.com>2018-05-10 12:38:36 -0700
commit5a509c47a20e0b81b95bb4932e8b19dfc6a402e2 (patch)
tree6c7e78b4d2c2d888ed0f68a993107e8272b010d8 /runsc/fsgofer
parent2d3c6dc2efb1d9957836d70d1a59634b96ea74d4 (diff)
Open file as read-write when mount points to a file
This is to allow files mapped directly, like /etc/hosts, to be writable. Closes #40 PiperOrigin-RevId: 196155920 Change-Id: Id2027e421cef5f94a0951c3e18b398a77c285bbd
Diffstat (limited to 'runsc/fsgofer')
-rw-r--r--runsc/fsgofer/fsgofer.go12
-rw-r--r--runsc/fsgofer/fsgofer_test.go50
2 files changed, 60 insertions, 2 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go
index be2ac5f3c..11dd28cef 100644
--- a/runsc/fsgofer/fsgofer.go
+++ b/runsc/fsgofer/fsgofer.go
@@ -98,7 +98,17 @@ func (a *attachPoint) Attach(appPath string) (p9.File, error) {
}
root := filepath.Join(a.prefix, appPath)
- f, err := os.OpenFile(root, openFlags|syscall.O_RDONLY, 0)
+ fi, err := os.Stat(root)
+ if err != nil {
+ return nil, err
+ }
+
+ mode := syscall.O_RDWR
+ if a.conf.ROMount || fi.IsDir() {
+ mode = syscall.O_RDONLY
+ }
+
+ f, err := os.OpenFile(root, mode|openFlags, 0)
if err != nil {
return nil, fmt.Errorf("unable to open file %q, err: %v", root, err)
}
diff --git a/runsc/fsgofer/fsgofer_test.go b/runsc/fsgofer/fsgofer_test.go
index 58d04aefa..249f67bf9 100644
--- a/runsc/fsgofer/fsgofer_test.go
+++ b/runsc/fsgofer/fsgofer_test.go
@@ -18,6 +18,7 @@ import (
"fmt"
"io/ioutil"
"os"
+ "path"
"syscall"
"testing"
@@ -102,7 +103,7 @@ func setup(ft fileType) (string, string, error) {
return "", "", fmt.Errorf("ioutil.TempDir() failed, err: %v", err)
}
- // First attach with writable configuiration to setup tree.
+ // First attach with writable configuration to setup tree.
a := NewAttachPoint(path, Config{})
root, err := a.Attach("/")
if err != nil {
@@ -574,3 +575,50 @@ func TestReaddir(t *testing.T) {
}
})
}
+
+// Test that attach point can be written to when it points to a file, e.g.
+// /etc/hosts.
+func TestAttachFile(t *testing.T) {
+ conf := Config{ROMount: false}
+ dir, err := ioutil.TempDir("", "root-")
+ if err != nil {
+ t.Fatalf("ioutil.TempDir() failed, err: %v", err)
+ }
+ defer os.RemoveAll(dir)
+
+ path := path.Join(dir, "test")
+ if _, err := os.Create(path); err != nil {
+ t.Fatalf("os.Create(%q) failed, err: %v", path, err)
+ }
+
+ a := NewAttachPoint(path, conf)
+ root, err := a.Attach("/")
+ if err != nil {
+ t.Fatalf("Attach(%q) failed, err: %v", "/", err)
+ }
+
+ if _, _, _, err := root.Open(p9.ReadWrite); err != nil {
+ t.Fatalf("Open(ReadWrite) failed, err: %v", err)
+ }
+ defer root.Close()
+
+ b := []byte("foobar")
+ w, err := root.WriteAt(b, 0)
+ if err != nil {
+ t.Fatalf("Write() failed, err: %v", err)
+ }
+ if w != len(b) {
+ t.Fatalf("Write() was partial, got: %d, expected: %d", w, len(b))
+ }
+ rBuf := make([]byte, len(b))
+ r, err := root.ReadAt(rBuf, 0)
+ if err != nil {
+ t.Fatalf("ReadAt() failed, err: %v", err)
+ }
+ if r != len(rBuf) {
+ t.Fatalf("ReadAt() was partial, got: %d, expected: %d", r, len(rBuf))
+ }
+ if string(rBuf) != "foobar" {
+ t.Fatalf("ReadAt() wrong data, got: %s, expected: %s", string(rBuf), "foobar")
+ }
+}