vyatta-cfg: remove unused unionfs mounts following unclean config exits

If a configuration session is exited uncleanly, either as a result of a
network disconnect / timeout or other forced quit from within config
mode, the unionfs mount is left in place.  These remain until the
system is rebooted, giving an error when unmounting the config
directory.

This commit checks for old configuartion directories when a user enters
config mode, removing any found that are owned by that user but not
part of any active configuration seesion.

Bug #564 http://bugzilla.vyos.net/show_bug.cgi?id=564

1 files changed, 130 insertions, 3 deletions

diff --git a/src/cstore/unionfs/cstore-unionfs.cpp b/src/cstore/unionfs/cstore-unionfs.cpp
index 379f3bf..dccb626 100644
--- a/src/cstore/unionfs/cstore-unionfs.cpp
+++ b/src/cstore/unionfs/cstore-unionfs.cpp
@@ -25,6 +25,10 @@
 #include <fcntl.h>
 #include <sys/mount.h>
 #include <wait.h>
+#include <dirent.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include <cli_cstore.h>
 #include <cstore/unionfs/cstore-unionfs.hpp>
@@ -163,6 +167,42 @@ _unescape_path_name(const string& path)
   return npath;
 }
 
+vector<int> getActiveCommits()
+{
+  string process_name = "vbash";
+  vector<int> pids;
+
+  DIR *dp = opendir("/proc");
+  if (dp != NULL) {
+    struct dirent *dirp;
+    while ((dirp = readdir(dp))) {
+      int pid = atoi(dirp->d_name);
+      if (pid > 0) {
+        string command_path = string("/proc/") + dirp->d_name + "/cmdline";
+        ifstream command_file(command_path.c_str());
+        string command_line;
+        getline(command_file, command_line);
+        if (!command_line.empty()) {
+          size_t pos = command_line.find('\0');
+          if (pos != string::npos) {
+            command_line = command_line.substr(0, pos);
+          }
+          pos = command_line.rfind('/');
+          if (pos != string::npos) {
+            command_line = command_line.substr(pos + 1);
+          }
+          if (process_name == command_line) {
+            pids.push_back(pid);
+          }
+        }
+      }
+    }
+  }
+
+  closedir(dp);
+
+  return pids;
+}
 
 ////// constructor/destructor
 /* "current session" constructor.
@@ -202,7 +242,6 @@ UnionfsCstore::UnionfsCstore(bool use_edit_level)
   if ((val = getenv(C_ENV_CHANGE_ROOT.c_str()))) {
     change_root = val;
   }
-
   /* note: the original perl API module does not use the edit levels
    *       from environment. only the actual CLI operations use them.
    *       so here make it an option.
@@ -342,6 +381,29 @@ UnionfsCstore::sessionChanged()
 bool
 UnionfsCstore::setupSession()
 {
+  vector<FsPath> directories;
+  vector<int> pids;
+  vector<int> old_pids;
+  FsPath old_config;
+  FsPath work_base;
+
+  string work_string = work_root.path_cstr();
+  work_base = work_string.erase(work_string.find_last_of("/"));
+
+  try {
+    b_fs::directory_iterator di(work_base.path_cstr());
+    for (; di != b_fs::directory_iterator(); ++di) {
+      old_config = di->path().file_string().c_str();
+      if (path_is_directory(old_config)) {
+        directories.push_back(old_config);
+      }
+    }
+  } catch (...) {
+    if (path_exists(active_root)) {
+      output_internal("no session directories found [%s]\n", work_root.path_cstr());
+    }
+  }
+
   if (!path_exists(work_root)) {
     // session doesn't exist. create dirs.
     try {
@@ -362,10 +424,75 @@ UnionfsCstore::setupSession()
       return false;
     }
   } else if (!path_is_directory(work_root)) {
-    output_internal("setup session not dir [%s]\n",
-                    work_root.path_cstr());
+    output_internal("setup session not dir [%s]\n", work_root.path_cstr());
     return false;
   }
+
+  pids = getActiveCommits();
+
+  struct stat config_info;
+  stat(work_root.path_cstr(), &config_info);
+  int current_uid = (int) config_info.st_uid;
+  bool failed = false;
+
+  for (size_t i = 0; i < directories.size(); i++) {
+    struct stat directory_info;
+    int directory_uid;
+    int current_pid = 0;
+
+    // find uid for the current directory and the active config directory
+
+    stat(directories[i].path_cstr(), &directory_info);
+    directory_uid = (int) directory_info.st_uid;
+
+    // remove old config session directories but only for the current user
+
+    if (directory_uid == current_uid) {
+      string config_match = work_base.path_cstr() + std::string("/new_config_");
+      string current_path = directories[i].path_cstr();
+
+      if (current_path.find(config_match) != std::string::npos) {
+        current_pid = atoi(current_path.erase(current_path.find(config_match), config_match.length()).c_str());
+
+        // umount only inactive config session directory, don't touch active sessions
+
+        if (std::find(pids.begin(), pids.end(), current_pid) == pids.end()) {
+          old_pids.push_back(current_pid);
+          output_internal("found inactive config [%d]\n", current_pid);
+          output_internal("umount [%s]\n", directories[i].path_cstr());
+          if (!do_umount(directories[i])) {
+            failed = true;
+          }
+        }
+      }
+    }
+  }
+
+  if (!old_pids.empty()) {
+    for (size_t i = 0; i < directories.size(); i++) {
+
+      int current_pid;
+      string current_path;
+
+      current_path = directories[i].path_cstr();
+      current_pid = atoi(current_path.erase(0, (current_path.find_last_of("_")) + 1).c_str());
+
+      if (std::find(old_pids.begin(), old_pids.end(), current_pid) != old_pids.end()) {
+        try {
+          if (b_fs::remove_all(directories[i].path_cstr()) == 0) {
+            failed = true;
+          }
+        } catch (...) {
+          failed = true;
+        }
+      }
+    }
+  }
+
+  if (failed) {
+    output_internal("failed to remove old config session directories\n");
+  }
+
   return true;
 }