client/Client.cc: prevent segfaulting

The segfaulting in the rmdir function is caused by calling
filepath::last_dentry() function.
last_dentry() function assumes that the bits vector has always at
least one element, which is not the case for the the filepath object
created with "/" input.
This commit also fixes other functions affected by this bug:
link, unlink, rename, mkdir, mknod and symlink.

Fixes: http://tracker.ceph.com/issues/9935
Signed-off-by: Michal Jarzabek <stiopa@gmail.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/src/test/libcephfs/test.cc b/src/test/libcephfs/test.cc
index 5f43f4ce2e8..baea14fcf35 100644
--- a/src/test/libcephfs/test.cc
+++ b/src/test/libcephfs/test.cc
@@ -1739,3 +1739,41 @@ TEST(LibCephFS, ClearSetuid) {
 
   ceph_shutdown(cmount);
 }
+
+TEST(LibCephFS, OperationsOnRoot)
+{
+  struct ceph_mount_info *cmount;
+  ASSERT_EQ(ceph_create(&cmount, NULL), 0);
+  ASSERT_EQ(ceph_conf_read_file(cmount, NULL), 0);
+  ASSERT_EQ(0, ceph_conf_parse_env(cmount, NULL));
+  ASSERT_EQ(ceph_mount(cmount, "/"), 0);
+
+  char dirname[32];
+  sprintf(dirname, "/somedir%x", getpid());
+
+  ASSERT_EQ(ceph_mkdir(cmount, dirname, 0755), 0);
+
+  ASSERT_EQ(ceph_rmdir(cmount, "/"), -EBUSY);
+
+  ASSERT_EQ(ceph_link(cmount, "/", "/"), -EEXIST);
+  ASSERT_EQ(ceph_link(cmount, dirname, "/"), -EEXIST);
+  ASSERT_EQ(ceph_link(cmount, "nonExisitingDir", "/"), -ENOENT);
+
+  ASSERT_EQ(ceph_unlink(cmount, "/"), -EISDIR);
+
+  ASSERT_EQ(ceph_rename(cmount, "/", "/"), -EBUSY);
+  ASSERT_EQ(ceph_rename(cmount, dirname, "/"), -EBUSY);
+  ASSERT_EQ(ceph_rename(cmount, "nonExistingDir", "/"), -EBUSY);
+  ASSERT_EQ(ceph_rename(cmount, "/", dirname), -EBUSY);
+  ASSERT_EQ(ceph_rename(cmount, "/", "nonExistingDir"), -EBUSY);
+
+  ASSERT_EQ(ceph_mkdir(cmount, "/", 0777), -EEXIST);
+
+  ASSERT_EQ(ceph_mknod(cmount, "/", 0, 0), -EEXIST);
+
+  ASSERT_EQ(ceph_symlink(cmount, "/", "/"), -EEXIST);
+  ASSERT_EQ(ceph_symlink(cmount, dirname, "/"), -EEXIST);
+  ASSERT_EQ(ceph_symlink(cmount, "nonExistingDir", "/"), -EEXIST);
+
+  ceph_shutdown(cmount);
+}