HDFS-13322 fuse dfs - uid persists when switching between ticket caches. Contributed by Istvan Fajth.

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/fuse-dfs/fuse_connect.c

@@ -192,7 +192,7 @@ int fuseConnectInit(const char *nnUri, int port)
 }
 
 /**
- * Compare two libhdfs connections by username
+ * Compare two libhdfs connections by username and Kerberos ticket cache path
  *
  * @param a                The first libhdfs connection
  * @param b                The second libhdfs connection
@@ -201,22 +201,26 @@ int fuseConnectInit(const char *nnUri, int port)
  */
 static int hdfsConnCompare(const struct hdfsConn *a, const struct hdfsConn *b)
 {
-  return strcmp(a->usrname, b->usrname);
+  int rc = strcmp(a->usrname, b->usrname);
+  if (rc) return rc;
+  return gHdfsAuthConf == AUTH_CONF_KERBEROS && strcmp(a->kpath, b->kpath);
 }
 
 /**
  * Find a libhdfs connection by username
  *
  * @param usrname         The username to look up
+ * @param kpath           The Kerberos ticket cache file path
  *
  * @return                The connection, or NULL if none could be found
  */
-static struct hdfsConn* hdfsConnFind(const char *usrname)
+static struct hdfsConn* hdfsConnFind(const char *usrname, const char *kpath)
 {
   struct hdfsConn exemplar;
 
   memset(&exemplar, 0, sizeof(exemplar));
   exemplar.usrname = (char*)usrname;
+  exemplar.kpath = (char*)kpath;
   return RB_FIND(hdfsConnTree, &gConnTree, &exemplar);
 }
 
@@ -542,8 +546,13 @@ static int fuseConnect(const char *usrname, struct fuse_context *ctx,
   int ret;
   struct hdfsConn* conn;
 
+  char kpath[PATH_MAX] = { 0 };
+  if (gHdfsAuthConf == AUTH_CONF_KERBEROS) {
+    findKerbTicketCachePath(ctx, kpath, sizeof(kpath));
+  }
+
   pthread_mutex_lock(&gConnMutex);
-  conn = hdfsConnFind(usrname);
+  conn = hdfsConnFind(usrname, kpath);
   if (!conn) {
     ret = fuseNewConnect(usrname, ctx, &conn);
     if (ret) {