Patch #954115: Fix os.stat handling of UNC roots.

Will backport to 2.3.

diff --git a/Misc/NEWS b/Misc/NEWS
index 33bfc43cecd439dcb3e11a4ca82a47967dc646fc..15630a3fd2d4f5826b361c6e67fbf60fb8c6f88d 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -210,6 +210,8 @@ Core and builtins
 Extension modules
 -----------------
 
+- nt now properly allows to refer to UNC roots, e.g. in nt.stat().
+
 - the weakref module now supports additional objects:  array.array,
   sre.pattern_objects, file objects, and sockets.
 

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 1df5af0329f6367b6df7d305a7b3e487563942c8..42bc767ea4d389fc453b7d02b1ce192cca6f6090 100644 (file)
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -892,6 +892,66 @@ _pystat_fromstructstat(STRUCT_STAT st)
        return v;
 }
 
+#ifdef MS_WINDOWS
+
+/* IsUNCRoot -- test whether the supplied path is of the form \\SERVER\SHARE\,
+   where / can be used in place of \ and the trailing slash is optional.
+   Both SERVER and SHARE must have at least one character.
+*/
+
+#define ISSLASHA(c) ((c) == '\\' || (c) == '/')
+#define ISSLASHW(c) ((c) == L'\\' || (c) == L'/')
+#define ARRAYSIZE(a) (sizeof(a) / sizeof(a[0]))
+
+static BOOL 
+IsUNCRootA(char *path, int pathlen)
+{
+       #define ISSLASH ISSLASHA
+
+       int i, share;
+
+       if (pathlen < 5 || !ISSLASH(path[0]) || !ISSLASH(path[1]))
+               /* minimum UNCRoot is \\x\y */
+               return FALSE;
+       for (i = 2; i < pathlen ; i++)
+               if (ISSLASH(path[i])) break;
+       if (i == 2 || i == pathlen)
+               /* do not allow \\\SHARE or \\SERVER */
+               return FALSE;
+       share = i+1;
+       for (i = share; i < pathlen; i++)
+               if (ISSLASH(path[i])) break;
+       return (i != share && (i == pathlen || i == pathlen-1));
+
+       #undef ISSLASH
+}
+
+#ifdef Py_WIN_WIDE_FILENAMES
+static BOOL 
+IsUNCRootW(Py_UNICODE *path, int pathlen)
+{
+       #define ISSLASH ISSLASHW
+
+       int i, share;
+
+       if (pathlen < 5 || !ISSLASH(path[0]) || !ISSLASH(path[1]))
+               /* minimum UNCRoot is \\x\y */
+               return FALSE;
+       for (i = 2; i < pathlen ; i++)
+               if (ISSLASH(path[i])) break;
+       if (i == 2 || i == pathlen)
+               /* do not allow \\\SHARE or \\SERVER */
+               return FALSE;
+       share = i+1;
+       for (i = share; i < pathlen; i++)
+               if (ISSLASH(path[i])) break;
+       return (i != share && (i == pathlen || i == pathlen-1));
+
+       #undef ISSLASH
+}
+#endif /* Py_WIN_WIDE_FILENAMES */
+#endif /* MS_WINDOWS */
+
 static PyObject *
 posix_do_stat(PyObject *self, PyObject *args,
              char *format,
@@ -931,15 +991,22 @@ posix_do_stat(PyObject *self, PyObject *args,
                        /* Remove trailing slash or backslash, unless it's the current
                           drive root (/ or \) or a specific drive's root (like c:\ or c:/).
                        */
-                       if (pathlen > 0 &&
-                               (wpath[pathlen-1]== L'\\' || wpath[pathlen-1] == L'/')) {
-                               /* It does end with a slash -- exempt the root drive cases. */
-                               /* XXX UNC root drives should also be exempted? */
-                               if (pathlen == 1 || (pathlen == 3 && wpath[1] == L':'))
-                               /* leave it alone */;
-                       else {
-                                       /* nuke the trailing backslash */
-                                       wpath[pathlen-1] = L'\0';
+                       if (pathlen > 0) {
+                               if (ISSLASHW(wpath[pathlen-1])) {
+                                       /* It does end with a slash -- exempt the root drive cases. */
+                                       if (pathlen == 1 || (pathlen == 3 && wpath[1] == L':') || 
+                                               IsUNCRootW(wpath, pathlen))
+                                               /* leave it alone */;
+                                       else {
+                                               /* nuke the trailing backslash */
+                                               wpath[pathlen-1] = L'\0';
+                                       }
+                               }
+                               else if (ISSLASHW(wpath[1]) && pathlen < ARRAYSIZE(wpath)-1 && 
+                                       IsUNCRootW(wpath, pathlen)) {
+                                       /* UNC root w/o trailing slash: add one when there's room */
+                                       wpath[pathlen++] = L'\\';
+                                       wpath[pathlen] = L'\0';
                                }
                        }
                        Py_BEGIN_ALLOW_THREADS
@@ -974,16 +1041,25 @@ posix_do_stat(PyObject *self, PyObject *args,
        /* Remove trailing slash or backslash, unless it's the current
           drive root (/ or \) or a specific drive's root (like c:\ or c:/).
        */
-       if (pathlen > 0 &&
-           (path[pathlen-1]== '\\' || path[pathlen-1] == '/')) {
-               /* It does end with a slash -- exempt the root drive cases. */
-               /* XXX UNC root drives should also be exempted? */
-               if (pathlen == 1 || (pathlen == 3 && path[1] == ':'))
-                       /* leave it alone */;
-               else {
-                       /* nuke the trailing backslash */
+       if (pathlen > 0) {
+               if (ISSLASHA(path[pathlen-1])) {
+                       /* It does end with a slash -- exempt the root drive cases. */
+                       if (pathlen == 1 || (pathlen == 3 && path[1] == ':') || 
+                               IsUNCRootA(path, pathlen))
+                               /* leave it alone */;
+                       else {
+                               /* nuke the trailing backslash */
+                               strncpy(pathcopy, path, pathlen);
+                               pathcopy[pathlen-1] = '\0';
+                               path = pathcopy;
+                       }
+               }
+               else if (ISSLASHA(path[1]) && pathlen < ARRAYSIZE(pathcopy)-1 && 
+                       IsUNCRootA(path, pathlen)) {
+                       /* UNC root w/o trailing slash: add one when there's room */
                        strncpy(pathcopy, path, pathlen);
-                       pathcopy[pathlen-1] = '\0';
+                       pathcopy[pathlen++] = '\\';
+                       pathcopy[pathlen] = '\0';
                        path = pathcopy;
                }
        }