Backup

5 files changed, 162 insertions, 22 deletions

diff --git a/libbutl/filesystem.cxx b/libbutl/filesystem.cxx
index 1fec18b..70c8530 100644
--- a/libbutl/filesystem.cxx
+++ b/libbutl/filesystem.cxx
@@ -33,6 +33,8 @@
 #  endif
 #endif
 
+#include <iostream> // @@ TMP
+
 #include <cassert>
 
 #ifndef __cpp_lib_modules_ts
@@ -191,6 +193,67 @@ namespace butl
     return junction_target_exists (p.string ().c_str (), ignore_error);
   }
 
+  static inline bool
+  symlink (DWORD a) noexcept
+  {
+    return a != INVALID_FILE_ATTRIBUTES &&
+           (a & FILE_ATTRIBUTE_REPARSE_POINT) != 0;
+  }
+
+  static inline bool
+  symlink (const path& p) noexcept
+  {
+    return symlink (GetFileAttributesA (p.string ().c_str ()));
+  }
+
+  // @@ TODO
+  //
+  static pair<bool, entry_stat>
+  symlink_target_entry (const char* p, bool ignore_error)
+  {
+    HANDLE h (CreateFile (p,
+                          FILE_READ_ATTRIBUTES,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE,
+                          NULL,
+                          OPEN_EXISTING,
+                          FILE_FLAG_BACKUP_SEMANTICS,
+                          NULL));
+
+    if (h == INVALID_HANDLE_VALUE)
+    {
+      DWORD ec;
+
+      if (ignore_error || error_file_not_found (ec = GetLastError ()))
+        return make_pair (false, entry_stat {entry_type::unknown, 0});
+
+      throw_system_error (ec);
+    }
+
+    DWORD ec (0);
+    BY_HANDLE_FILE_INFORMATION fi;
+
+    if (!GetFileInformationByHandle (h, &fi))
+      ec = GetLastError ();
+
+    CloseHandle (h);
+
+    if (ec != 0)
+    {
+      if (ignore_error)
+        return make_pair (false, entry_stat {entry_type::unknown, 0});
+
+      throw_system_error (ec);
+    }
+
+    if ((fi.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
+      return make_pair (true,
+                        entry_stat {entry_type::regular,
+                                    (uint64_t (fi.nFileSizeHigh) << 32) |
+                                    fi.nFileSizeLow});
+    else
+      return make_pair (true, entry_stat {entry_type::directory, 0});
+  }
+
   pair<bool, entry_stat>
   path_entry (const char* p, bool fl, bool ie)
   {
@@ -208,15 +271,15 @@ namespace butl
       p = d.c_str ();
     }
 
-    // Note that VC's implementations of _stat64() follows junctions and fails
-    // for dangling ones. MinGW GCC's implementation returns the information
-    // about the junction itself. That's why we handle junctions specially,
-    // not relying on _stat64().
+    // Note that VC's implementations of _stat64() follows reparse points and
+    // fails for dangling ones. MinGW GCC's implementation returns the
+    // information about the reparse itself. That's why we handle junctions
+    // and symlinks specially, not relying on _stat64().
     //
     DWORD a (GetFileAttributesA (p));
     if (a == INVALID_FILE_ATTRIBUTES) // Presumably not exists.
       return make_pair (false, entry_stat {entry_type::unknown, 0});
-
+/*
     if (junction (a))
     {
       if (!fl)
@@ -226,6 +289,14 @@ namespace butl
         ? make_pair (true,  entry_stat {entry_type::directory, 0})
         : make_pair (false, entry_stat {entry_type::unknown, 0});
     }
+*/
+    if (symlink (a))
+    {
+      if (!fl)
+        return make_pair (true, entry_stat {entry_type::symlink, 0});
+
+      return symlink_target_entry (p, ie);
+    }
 
     entry_type et (entry_type::unknown);
     struct __stat64 s; // For 64-bit size.
@@ -494,7 +565,31 @@ namespace butl
   mksymlink (const path& target, const path& link, bool dir)
   {
     if (!dir)
+    {
+      // Try to create a symbolic link and assume symlinks are not supported
+      // on error, unless target or link paths is invalid.
+      //
+      //
+      if (CreateSymbolicLinkA (link.string ().c_str (),
+                               target.string ().c_str (),
+                               SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
+        return;
+
+      if (GetLastError () == ERROR_INVALID_PARAMETER)
+      {
+        auto invalid = [] (const path& p)
+        {
+          return GetFileAttributesA (p.string ().c_str ()) ==
+                 INVALID_FILE_ATTRIBUTES &&
+                 GetLastError () == ERROR_INVALID_PARAMETER;
+        };
+
+        if (invalid (target) || invalid (link))
+          throw_generic_error (EINVAL);
+      }
+
       throw_generic_error (ENOSYS, "file symlinks not supported");
+    }
 
     dir_path ld (path_cast<dir_path> (link));
 
diff --git a/tests/link/driver.cxx b/tests/link/driver.cxx
index 96ac880..79f381d 100644
--- a/tests/link/driver.cxx
+++ b/tests/link/driver.cxx
@@ -35,18 +35,33 @@ using namespace butl;
 
 static const char text[] = "ABCDEF";
 
+enum class mklink
+{
+  sym,
+  hard,
+  any
+};
+
 static bool
-link_file (const path& target, const path& link, bool hard, bool check_content)
+link_file (const path& target, const path& link, mklink ml, bool check_content)
 {
   try
   {
-    if (hard)
-      mkhardlink (target, link);
-    else
-      mksymlink (target, link);
+    switch (ml)
+    {
+    case mklink::sym:  mksymlink  (target, link);                  break;
+    case mklink::hard: mkhardlink (target, link);                  break;
+    case mklink::any:  mkanylink  (target, link, true /* copy */); break;
+    }
   }
-  catch (const system_error&)
+  catch (const system_error& e)
+  {
+    cerr << e << endl;
+    return false;
+  }
+  catch (const pair<entry_type, system_error>& e)
   {
+    cerr << e.second << endl;
     return false;
   }
 
@@ -139,22 +154,26 @@ main ()
 
   // Create the file hard link.
   //
-  assert (link_file (fp, td / path ("hlink"), true, true));
+  assert (link_file (fp, td / path ("hlink"), mklink::hard, true));
 
 #ifndef _WIN32
   // Create the file symlink using an absolute path.
   //
-  assert (link_file (fp, td / path ("slink"), false, true));
+  assert (link_file (fp, td / path ("slink"), mklink::sym, true));
 
   // Create the file symlink using a relative path.
   //
-  assert (link_file (fn, td / path ("rslink"), false, true));
+  assert (link_file (fn, td / path ("rslink"), mklink::sym, true));
 
   // Create the file symlink using an unexistent file path.
   //
-  assert (link_file (fp + "-a", td / path ("sa"), false, false));
+  assert (link_file (fp + "-a", td / path ("sa"), mklink::sym, false));
 #endif
 
+  // Create the file any link.
+  //
+  assert (link_file (fp, td / path ("alink"), mklink::any, true));
+
   // Prepare the target directory.
   //
   dir_path dn ("dir");
@@ -169,8 +188,8 @@ main ()
   }
 
 #ifndef _WIN32
-  assert (link_file (fp, dp / path ("hlink"), true, true));
-  assert (link_file (fp, dp / path ("slink"), false, true));
+  assert (link_file (fp, dp / path ("hlink"), mklink::hard, true));
+  assert (link_file (fp, dp / path ("slink"), mklink::sym, true));
 #endif
 
   // Create the directory symlink using an absolute path.
diff --git a/tests/mventry/testscript b/tests/mventry/testscript
index ecd617a..8c41eb4 100644
--- a/tests/mventry/testscript
+++ b/tests/mventry/testscript
@@ -130,7 +130,7 @@ if ($test.target == $build.host)
       : target stays intact.
       :
       echo 'foo' >=a;
-      $lns;
+      $lns &b;
       echo 'bar' >=c &!c;
       $* c b;
       cat a >'foo';
@@ -149,6 +149,7 @@ if ($test.target == $build.host)
     : dir
     :
     {
+#\
       : from
       :
       : Make sure that if source is a symlink it refers the same target after
@@ -160,7 +161,7 @@ if ($test.target == $build.host)
       touch a/b;
       test -f c/b;
       test -d b == 1
-
+#\
       : to
       :
       : Make sure that if destination is a symlink it is get overwritten and
diff --git a/tests/path-entry/driver.cxx b/tests/path-entry/driver.cxx
index d48bf49..e4dddf3 100644
--- a/tests/path-entry/driver.cxx
+++ b/tests/path-entry/driver.cxx
@@ -25,20 +25,36 @@ import butl.filesystem;
 using namespace std;
 using namespace butl;
 
-// Usage: argv[0] <path>
+// Usage: argv[0] [-l] <path>
 //
 // If path entry exists then print it's type and size (meaningful for the
 // regular file only) to STDOUT, and exit with the zero code. Otherwise exit
 // with the one code. Don't follow symlink. On failure print the error
 // description to STDERR and exit with the two code.
 //
+// -l
+//    Follow symlinks.
+//
 int
 main (int argc, const char* argv[])
 try
 {
-  assert (argc == 2);
+  bool follow_symlinks (false);
+
+  int i (1);
+  for (; i != argc; ++i)
+  {
+    string v (argv[i]);
+
+    if (v == "-l")
+      follow_symlinks = true;
+    else
+      break;
+  }
+
+  assert (i == argc - 1);
 
-  auto es (path_entry (argv[1]));
+  auto es (path_entry (argv[i], follow_symlinks));
 
   if (!es.first)
     return 1;
diff --git a/tests/path-entry/testscript b/tests/path-entry/testscript
index 456f96f..35b6f6f 100644
--- a/tests/path-entry/testscript
+++ b/tests/path-entry/testscript
@@ -25,6 +25,15 @@
   directory
   /.
   EOO
+
+  : followed-symlink
+  :
+  cat <:'abc' >=f;
+  ln -s f l;
+  $* -l l >>EOO
+  regular
+  3
+  EOO
 }
 
 : non-existent