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authorJakob Unterwurzacher2018-09-22 19:41:58 +0200
committerJakob Unterwurzacher2018-09-23 12:17:26 +0200
commit05c8d4a1c459dc4c73918af898119b1e17b1c0ce (patch)
tree2c1d6b7d71041f2df09e804579e610f04e7c9b82
parent2d01d5f2d4bb1fc9c7a7bb9165edcef42d4f89c6 (diff)
tests: add symlink_race tool
Help uncover symlink races.
-rw-r--r--tests/symlink_race/.gitignore3
-rw-r--r--tests/symlink_race/main.go91
2 files changed, 94 insertions, 0 deletions
diff --git a/tests/symlink_race/.gitignore b/tests/symlink_race/.gitignore
new file mode 100644
index 0000000..45df5f8
--- /dev/null
+++ b/tests/symlink_race/.gitignore
@@ -0,0 +1,3 @@
+symlink_race.test_file.tmp
+symlink_race.test_file
+symlink_race
diff --git a/tests/symlink_race/main.go b/tests/symlink_race/main.go
new file mode 100644
index 0000000..6fb794f
--- /dev/null
+++ b/tests/symlink_race/main.go
@@ -0,0 +1,91 @@
+package main
+
+import (
+ "fmt"
+ "os"
+ "syscall"
+ "time"
+)
+
+const (
+ testFile = "symlink_race.test_file"
+ testFileTmp = testFile + ".tmp"
+)
+
+func renameLoop() {
+ // May be left behind from an earlier run
+ syscall.Unlink(testFileTmp)
+
+ var err error
+ var fd *os.File
+ for {
+ err = syscall.Symlink("/root/chmod_me", testFileTmp)
+ if err != nil {
+ fmt.Printf("Symlink() failed: %v\n", err)
+ continue
+ }
+ err = syscall.Rename(testFileTmp, testFile)
+ if err != nil {
+ fmt.Printf("Rename() 1 failed: %v\n", err)
+ continue
+ }
+ fd, err = os.Create(testFileTmp)
+ if err != nil {
+ fmt.Printf("Create() failed: %v\n", err)
+ continue
+ }
+ fd.Close()
+ err = syscall.Rename(testFileTmp, testFile)
+ if err != nil {
+ fmt.Printf("Rename() 2 failed: %v\n", err)
+ continue
+ }
+ fmt.Printf(".")
+ }
+}
+
+func chmodLoop() {
+ var err error
+ for {
+ err = syscall.Chmod(testFile, 0777)
+ if err != nil {
+ fmt.Printf("Chmod() failed: %v\n", err)
+ } else {
+ fmt.Printf("Chmod() ok\n")
+ }
+ time.Sleep(100 * time.Microsecond)
+ }
+}
+
+func openLoop() {
+ var err error
+ var f *os.File
+ buf := make([]byte, 100)
+ owned := []byte("owned")
+ var n int
+ for {
+ f, err = os.OpenFile(testFile, os.O_RDWR, 0777)
+ if err != nil {
+ fmt.Printf("Open() failed: %v\n", err)
+ continue
+ }
+ _, err = f.Write(owned)
+ if err != nil {
+ fmt.Printf("Write() failed: %v\n", err)
+ }
+ n, err = f.Read(buf)
+ if err != nil {
+ fmt.Printf("Read() failed: %v\n", err)
+ continue
+ }
+ if n > 0 {
+ fmt.Printf("Content: %q\n", string(buf[:n]))
+ os.Exit(1)
+ }
+ }
+}
+
+func main() {
+ go openLoop()
+ renameLoop()
+}