Kill apps using storage through bind mounts.

am: 89f74fbf25

* commit '89f74fbf2529d708534c041d2b711af0f1feff9f':
  Kill apps using storage through bind mounts.

EmulatedVolume.cpp

@@ -113,6 +113,7 @@ status_t EmulatedVolume::doUnmount() {
         mFusePid = 0;
     }
 
+    KillProcessesUsingPath(getPath());
     ForceUnmount(mFuseDefault);
     ForceUnmount(mFuseRead);
     ForceUnmount(mFuseWrite);

Process.cpp

@@ -177,13 +177,14 @@ extern "C" void vold_killProcessesWithOpenFiles(const char *path, int signal) {
 /*
  * Hunt down processes that have files open at the given mount point.
  */
-void Process::killProcessesWithOpenFiles(const char *path, int signal) {
-    DIR*    dir;
+int Process::killProcessesWithOpenFiles(const char *path, int signal) {
+    int count = 0;
+    DIR* dir;
     struct dirent* de;
 
     if (!(dir = opendir("/proc"))) {
         SLOGE("opendir failed (%s)", strerror(errno));
-        return;
+        return count;
     }
 
     while ((de = readdir(dir))) {
@@ -213,7 +214,9 @@ void Process::killProcessesWithOpenFiles(const char *path, int signal) {
         if (signal != 0) {
             SLOGW("Sending %s to process %d", strsignal(signal), pid);
             kill(pid, signal);
+            count++;
         }
     }
     closedir(dir);
+    return count;
 }

Process.h

@@ -21,7 +21,7 @@
 
 class Process {
 public:
-    static void killProcessesWithOpenFiles(const char *path, int signal);
+    static int killProcessesWithOpenFiles(const char *path, int signal);
     static int getPid(const char *s);
     static int checkSymLink(int pid, const char *path, const char *name);
     static int checkFileMaps(int pid, const char *path);

Utils.cpp

@@ -123,35 +123,57 @@ status_t ForceUnmount(const std::string& path) {
     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
-    PLOG(WARNING) << "Failed to unmount " << path;
-
+    // Apps might still be handling eject request, so wait before
+    // we start sending signals
     sleep(5);
-    Process::killProcessesWithOpenFiles(cpath, SIGINT);
 
+    Process::killProcessesWithOpenFiles(cpath, SIGINT);
+    sleep(5);
     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
-    PLOG(WARNING) << "Failed to unmount " << path;
 
-    sleep(5);
     Process::killProcessesWithOpenFiles(cpath, SIGTERM);
-
+    sleep(5);
     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
-    PLOG(WARNING) << "Failed to unmount " << path;
 
-    sleep(5);
     Process::killProcessesWithOpenFiles(cpath, SIGKILL);
-
+    sleep(5);
     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
-    PLOG(ERROR) << "Failed to unmount " << path;
 
     return -errno;
 }
 
+status_t KillProcessesUsingPath(const std::string& path) {
+    const char* cpath = path.c_str();
+    if (Process::killProcessesWithOpenFiles(cpath, SIGINT) == 0) {
+        return OK;
+    }
+    sleep(5);
+
+    if (Process::killProcessesWithOpenFiles(cpath, SIGTERM) == 0) {
+        return OK;
+    }
+    sleep(5);
+
+    if (Process::killProcessesWithOpenFiles(cpath, SIGKILL) == 0) {
+        return OK;
+    }
+    sleep(5);
+
+    // Send SIGKILL a second time to determine if we've
+    // actually killed everyone with open files
+    if (Process::killProcessesWithOpenFiles(cpath, SIGKILL) == 0) {
+        return OK;
+    }
+    PLOG(ERROR) << "Failed to kill processes using " << path;
+    return -EBUSY;
+}
+
 status_t BindMount(const std::string& source, const std::string& target) {
     if (::mount(source.c_str(), target.c_str(), "", MS_BIND, NULL)) {
         PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;

Utils.h

@@ -49,6 +49,9 @@ status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid);
 /* Really unmounts the path, killing active processes along the way */
 status_t ForceUnmount(const std::string& path);
 
+/* Kills any processes using given path */
+status_t KillProcessesUsingPath(const std::string& path);
+
 /* Creates bind mount from source to target */
 status_t BindMount(const std::string& source, const std::string& target);