Merge pull request #122 from dscho/fix-stdio-with-app-exec-aliases-msys2

Fix stdio with app execution aliases (Microsoft Store applications)

Author: dscho

winsup/cygwin/fhandler/termios.cc

@@ -702,24 +702,43 @@ fhandler_termios::fstat (struct stat *buf)
 }
 
 static bool
-is_console_app (const WCHAR *filename)
+is_console_app (path_conv &pc)
 {
+  tmp_pathbuf tp;
+  WCHAR *native_path = tp.w_get ();
+  pc.get_wide_win32_path (native_path);
+
+  wchar_t *e = wcsrchr (native_path, L'.');
+  if (e && (wcscasecmp (e, L".bat") == 0 || wcscasecmp (e, L".cmd") == 0))
+    return true;
+
+  if (pc.is_app_execution_alias ())
+    {
+      UNICODE_STRING upath;
+      RtlInitUnicodeString (&upath, native_path);
+      path_conv target (&upath, PC_SYM_FOLLOW);
+      target.get_wide_win32_path (native_path);
+    }
+
   HANDLE h;
-  h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,
+  h = CreateFileW (native_path, GENERIC_READ, FILE_SHARE_READ,
 		   NULL, OPEN_EXISTING, 0, NULL);
+  if (h == INVALID_HANDLE_VALUE)
+    return true;
   char buf[1024];
   DWORD n;
-  ReadFile (h, buf, sizeof (buf), &n, 0);
+  BOOL res = ReadFile (h, buf, sizeof (buf), &n, 0);
   CloseHandle (h);
+  if (!res)
+    return true;
   /* The offset of Subsystem is the same for both IMAGE_NT_HEADERS32 and
      IMAGE_NT_HEADERS64, so only IMAGE_NT_HEADERS32 is used here. */
   IMAGE_NT_HEADERS32 *p = (IMAGE_NT_HEADERS32 *) memmem (buf, n, "PE\0\0", 4);
   if (p && (char *) &p->OptionalHeader.DllCharacteristics <= buf + n)
     return p->OptionalHeader.Subsystem == IMAGE_SUBSYSTEM_WINDOWS_CUI;
-  wchar_t *e = wcsrchr (filename, L'.');
-  if (e && (wcscasecmp (e, L".bat") == 0 || wcscasecmp (e, L".cmd") == 0))
-    return true;
-  return false;
+  /* Return true for unknown to avoid standard handles from being unset.
+     Setting-up standard handles for GUI apps is pointless, but not unsafe. */
+  return true;
 }
 
 int
@@ -755,7 +774,7 @@ fhandler_termios::ioctl (unsigned int cmd, void *varg)
 
 void
 fhandler_termios::spawn_worker::setup (bool iscygwin, HANDLE h_stdin,
-				       const WCHAR *runpath, bool nopcon,
+				       path_conv &pc, bool nopcon,
 				       bool reset_sendsig,
 				       const WCHAR *envblock)
 {
@@ -794,7 +813,7 @@ fhandler_termios::spawn_worker::setup (bool iscygwin, HANDLE h_stdin,
 	    ptys->setup_locale ();
 	  }
     }
-  if (!iscygwin && ptys_primary && is_console_app (runpath))
+  if (!iscygwin && ptys_primary && is_console_app (pc))
     {
       if (h_stdin == ptys_primary->get_handle_nat ())
 	stdin_is_ptys = true;

winsup/cygwin/local_includes/fhandler.h

@@ -2035,7 +2035,7 @@ class fhandler_termios: public fhandler_base
     spawn_worker () :
       ptys_need_cleanup (false), cons_need_cleanup (false),
       stdin_is_ptys (false), ptys_ttyp (NULL) {}
-    void setup (bool iscygwin, HANDLE h_stdin, const WCHAR *runpath,
+    void setup (bool iscygwin, HANDLE h_stdin, path_conv &pc,
 		bool nopcon, bool reset_sendsig, const WCHAR *envblock);
     bool need_cleanup () { return ptys_need_cleanup || cons_need_cleanup; }
     void cleanup ();

winsup/cygwin/local_includes/path.h

@@ -79,6 +79,7 @@ enum path_types
   PATH_SOCKET		= _BIT ( 5),	/* AF_UNIX socket file */
   PATH_RESOLVE_PROCFD	= _BIT ( 6),	/* fd symlink via /proc */
   PATH_REP_NOAPI	= _BIT ( 7),	/* rep. point unknown to WinAPI */
+  PATH_APPEXECLINK	= _BIT ( 8),	/* rep. point app execution alias */
   PATH_DONT_USE		= _BIT (31)	/* conversion to signed happens. */
 };
 
@@ -214,6 +215,10 @@ class path_conv
   {
     return (path_flags & (PATH_REP | PATH_REP_NOAPI)) == PATH_REP;
   }
+  int is_app_execution_alias () const
+  {
+    return path_flags & PATH_APPEXECLINK;
+  }
 
   int isfifo () const {return dev.is_device (FH_FIFO);}
   int iscygdrive () const {return dev.is_device (FH_CYGDRIVE);}

winsup/cygwin/path.cc

@@ -2946,7 +2946,7 @@ check_reparse_point_target (HANDLE h, bool remote, PREPARSE_DATA_BUFFER rp,
 	  if (i == 2 && n > 0 && n < size)
 	    {
 	      RtlInitCountedUnicodeString (psymbuf, buf, n * sizeof (WCHAR));
-	      return PATH_SYMLINK | PATH_REP;
+	      return PATH_SYMLINK | PATH_REP | PATH_APPEXECLINK;
 	    }
 	  if (i == 2)
 	    break;

winsup/cygwin/spawn.cc

@@ -609,7 +609,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
 
       bool no_pcon = mode != _P_OVERLAY && mode != _P_WAIT;
       term_spawn_worker.setup (iscygwin (), handle (fileno_stdin, false),
-			       runpath, no_pcon, reset_sendsig, envblock);
+			       real_path, no_pcon, reset_sendsig, envblock);
 
       /* Set up needed handles for stdio */
       si.dwFlags = STARTF_USESTDHANDLES;