From 216720de55359828c2dc915b50e6ead44e00cd15 Mon Sep 17 00:00:00 2001
From: Beman <bdawes@acm.org>
Date: Wed, 23 Nov 2016 09:58:43 -0500
Subject: [PATCH] Fix #12495, create_directories() crashes when passed empty
 string as path, from Samantha Ritter. Also affected create_directory().
 Charles Olivi submitted a pull request with some particularly helpful test
 cases.

---
 doc/release_history.html |  4 ++++
 src/operations.cpp       | 15 +++++++++++++-
 test/operations_test.cpp | 43 ++++++++++++++++++++++++++++++++++++----
 3 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/doc/release_history.html b/doc/release_history.html
index 074fc29ac..840c79ec0 100644
--- a/doc/release_history.html
+++ b/doc/release_history.html
@@ -62,6 +62,10 @@ <h2>1.63.0</h2>
   recursive_directory_iterator</code> equality testing has existed more than a 
   dozen years. Nowadays test driven development would likely have detected the 
   problem in early development. Sigh.</li>
+  <li>Fix <a href="https://svn.boost.org/trac/boost/ticket/12495">#12495</a>, <i>
+  <code>create_directories()</code> crashes when passed empty string as path</i>, 
+  from Samantha Ritter. Also affected <code>create_directory()</code>. Charles 
+  Olivi submitted a pull request with some particularly helpful test cases.</li>
   <li>Fix broken link to
   <a href="https://svn.boost.org/trac/boost/ticket/7506">#7506</a> in 1.60.0 Release History (Daniel Krügler).</li>
   <li>Refactor <code>push_directory()</code>internal logic so it is easier to 
diff --git a/src/operations.cpp b/src/operations.cpp
index f34b07612..1b3298e3a 100644
--- a/src/operations.cpp
+++ b/src/operations.cpp
@@ -937,6 +937,17 @@ namespace detail
  BOOST_FILESYSTEM_DECL
   bool create_directories(const path& p, system::error_code* ec)
   {
+   if (p.empty())
+   {
+     if (ec == 0)
+       BOOST_FILESYSTEM_THROW(filesystem_error(
+         "boost::filesystem::create_directories", p,
+         system::errc::make_error_code(system::errc::invalid_argument)));
+     else
+       ec->assign(system::errc::invalid_argument, system::generic_category());
+     return false;
+   }
+
     if (p.filename_is_dot() || p.filename_is_dot_dot())
       return create_directories(p.parent_path(), ec);
     
@@ -990,7 +1001,8 @@ namespace detail
     //  attempt to create directory failed
     int errval(BOOST_ERRNO);  // save reason for failure
     error_code dummy;
-    if (errval == BOOST_ERROR_ALREADY_EXISTS && is_directory(p, dummy))
+
+    if (is_directory(p, dummy))
     {
       if (ec != 0)
         ec->clear();
@@ -1003,6 +1015,7 @@ namespace detail
         p, error_code(errval, system_category())));
     else
       ec->assign(errval, system_category());
+
     return false;
   }
 
diff --git a/test/operations_test.cpp b/test/operations_test.cpp
index 09c28e036..400b12bd8 100644
--- a/test/operations_test.cpp
+++ b/test/operations_test.cpp
@@ -1038,8 +1038,26 @@ namespace
   {
     cout << "create_directory_tests..." << endl;
 
-    BOOST_TEST(!fs::create_directory("."));
-    BOOST_TEST(!fs::create_directory(".."));
+    error_code ec;
+    BOOST_TEST(!fs::create_directory("", ec));
+    BOOST_TEST(ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directory(" ", ec));
+    BOOST_TEST(ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directory("/", ec));
+    BOOST_TEST(!ec);
+    BOOST_TEST(fs::is_directory("/"));  // this is a post-condition
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directory(".", ec));
+    BOOST_TEST(!ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directory("..", ec));
+    BOOST_TEST(!ec);
 
     // create a directory, then check it for consistency
     //   take extra care to report problems, since if this fails
@@ -1114,7 +1132,25 @@ namespace
   {
     cout << "create_directories_tests..." << endl;
 
-    BOOST_TEST(!fs::create_directories("/")); 
+    error_code ec;
+    BOOST_TEST(!fs::create_directories("", ec));
+    BOOST_TEST(ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directories(" ", ec));
+    BOOST_TEST(ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directories("/", ec));
+    BOOST_TEST(!ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directories(".", ec));
+    BOOST_TEST(ec);
+
+    ec.clear();
+    BOOST_TEST(!fs::create_directories("..", ec));
+    BOOST_TEST(ec);
 
     fs::path p = dir / "level1/." / "level2/./.." / "level3/";
     // trailing "/.", "/./..", and "/" in the above elements test ticket #7258 and
@@ -1128,7 +1164,6 @@ namespace
 
     if (fs::exists("/permissions_test"))
     {
-      error_code ec;
       BOOST_TEST(!fs::create_directories("/permissions_test", ec));
       BOOST_TEST(!fs::create_directories("/permissions_test/another_directory", ec));
       BOOST_TEST(ec);