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-rw-r--r--sendsig.go42
1 files changed, 42 insertions, 0 deletions
diff --git a/sendsig.go b/sendsig.go
new file mode 100644
index 0000000..d0e1cbb
--- /dev/null
+++ b/sendsig.go
@@ -0,0 +1,42 @@
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "syscall"
+)
+
+// cmdline looks like this: /bin/bash \0 /path/to/gocryptfs \0 --zerokey \0 ...
+const (
+ WRAPPER_PREFIX = "/bin/bash\000"
+ WRAPPER_CONTAINS = "gocryptfs\000"
+)
+
+// Send USR1 to the "gocryptfs" wrapper shell script. This notifies it that the
+// mounting has completed sucessfully.
+//
+// Checks /proc/$PPID/cmdline to make sure we do not kill an unrelated process.
+func sendSig() {
+ ppid := os.Getppid()
+ fn := fmt.Sprintf("/proc/%d/cmdline", ppid)
+ cmdline, err := ioutil.ReadFile(fn)
+ if err != nil {
+ fmt.Printf("sendSig: ReadFile: %v\n", err)
+ return
+ }
+ if bytes.HasPrefix(cmdline, []byte(WRAPPER_PREFIX)) && bytes.Contains(cmdline, []byte(WRAPPER_CONTAINS)) {
+ p, err := os.FindProcess(ppid)
+ if err != nil {
+ fmt.Printf("sendSig: FindProcess: %v\n", err)
+ return
+ }
+ err = p.Signal(syscall.SIGUSR1)
+ if err != nil {
+ fmt.Printf("sendSig: Signal: %v\n", err)
+ }
+ } else {
+ fmt.Printf("Not running under the gocryptfs wrapper - will not daemonize\n")
+ }
+}