ash: support UNC paths in cd command

1 files changed, 20 insertions, 13 deletions

diff --git a/shell/ash.c b/shell/ash.c
index ce6e355eb..c3e950893 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2581,6 +2581,7 @@ updatepwd(const char *dir)
 {
 #if ENABLE_PLATFORM_MINGW32
 #define is_path_sep(x) ((x) == '/' || (x) == '\\')
+#define is_unc_path(x) (is_path_sep(x[0]) && is_path_sep(x[1]))
         /*
          * Due to Windows drive notion, getting pwd is a completely
          * different thing. Handle it in a separate routine
@@ -2591,10 +2592,11 @@ updatepwd(const char *dir)
         char *cdcomppath;
         const char *lim;
         /*
-         * There are four cases
+         * There are five cases that make some kind of sense
          *  absdrive +  abspath: c:/path
          *  absdrive + !abspath: c:path
          * !absdrive +  abspath: /path
+         * !absdrive +  uncpath: //host/share
          * !absdrive + !abspath: path
          *
          * Damn DOS!
@@ -2606,7 +2608,6 @@ updatepwd(const char *dir)
          */
         int absdrive = *dir && dir[1] == ':';
         int abspath = absdrive ? is_path_sep(dir[2]) : is_path_sep(*dir);
-        char *drive;
 
         cdcomppath = ststrdup(dir);
         STARTSTACKSTR(new);
@@ -2619,19 +2620,25 @@ updatepwd(const char *dir)
         }
         new = makestrspace(strlen(dir) + 2, new);
 
-        drive = stackblock();
-        if (absdrive) {
-                *drive = *dir;
-                cdcomppath += 2;
-                dir += 2;
-        } else {
-                *drive = *curdir;
+        if ( is_unc_path(dir) || (!absdrive && !abspath && is_unc_path(curdir)) ) {
+                lim = (char *)stackblock() + 1;
+        }
+        else {
+                char *drive = stackblock();
+                if (absdrive) {
+                        *drive = *dir;
+                        cdcomppath += 2;
+                        dir += 2;
+                } else {
+                        *drive = *curdir;
+                }
+                drive[1] = ':'; /* in case of absolute drive+path */
+
+                if (abspath)
+                        new = drive + 2;
+                lim = drive + 3;
         }
-        drive[1] = ':'; /* in case of absolute drive+path */
 
-        if (abspath)
-                new = drive + 2;
-        lim = drive + 3;
         if (!abspath) {
                 if (!is_path_sep(new[-1]))
                         USTPUTC('/', new);