win32: track current directory of mapped drives

Drives mapped to a network share or path didn't have their current
directory tracked when using path names of the form 'c:path'.

This was because commit 585d17d26 used realpath(3) to canonicalise
paths in chdir(2).  Use readlink(2) instead so that mapped drives
aren't canonicalised but symlinks are resolved.

See GitHub issue #147.

1 files changed, 7 insertions, 4 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index ec7d6c456..22a3ede58 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1204,13 +1204,16 @@ int mingw_mkdir(const char *path, int mode UNUSED_PARAM)
 #undef chdir
 int mingw_chdir(const char *dirname)
 {
+        struct stat st;
         int ret = -1;
-        char *realdir = xmalloc_realpath(dirname);
+        const char *realdir = dirname;
+
+        if (lstat(dirname, &st) == 0 && S_ISLNK(st.st_mode))
+                realdir = auto_string(xmalloc_readlink(dirname));
 
-        if (realdir) {
+        if (realdir)
                 ret = chdir(realdir);
-                free(realdir);
-        }
+
         return ret;
 }