win32: canonicalize path in chdir(2)

Provide an implementation of chdir(2) which canonicalizes the
path to resolve symlinks.  Otherwise changing to a symlinked
directory confuses 'ls -l' because it thinks '.' is a link
rather than a directory.

OTOH, using 'cd' in the shell to change to a symlinked directory
now results in a mismatch between the shell's idea of where we are
and what's displayed in the prompt.  But upstream BusyBox does
that too so it must be OK.

2 files changed, 15 insertions, 0 deletions

diff --git a/include/mingw.h b/include/mingw.h
index b5324e49b..9bc5eb018 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -271,9 +271,11 @@ mode_t mingw_umask(mode_t mode);
 IMPL(fchmod,int,0,int fildes UNUSED_PARAM, mode_t mode UNUSED_PARAM);
 NOIMPL(fchown,int fd UNUSED_PARAM, uid_t uid UNUSED_PARAM, gid_t gid UNUSED_PARAM);
 int mingw_mkdir(const char *path, int mode);
+int mingw_chdir(const char *path);
 int mingw_chmod(const char *path, int mode);
 
 #define mkdir mingw_mkdir
+#define chdir mingw_chdir
 #define chmod mingw_chmod
 
 #if ENABLE_LFS && !defined(__MINGW64_VERSION_MAJOR)
diff --git a/win32/mingw.c b/win32/mingw.c
index c42dbed97..b1a8b9711 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1159,6 +1159,19 @@ int mingw_mkdir(const char *path, int mode UNUSED_PARAM)
         return ret;
 }
 
+#undef chdir
+int mingw_chdir(const char *dirname)
+{
+        int ret = -1;
+        char *realdir = xmalloc_realpath(dirname);
+
+        if (realdir) {
+                ret = chdir(realdir);
+                free(realdir);
+        }
+        return ret;
+}
+
 #undef chmod
 int mingw_chmod(const char *path, int mode)
 {