Implement sh -> cmd.exe translation hack.

* winsup/cygwin/spawn.cc (spawnve): Rewrite /bin/sh -c cmd
invocations to use cmd.exe /c cmd instead.

1 files changed, 15 insertions, 0 deletions

diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index f56eb547f..663fde2d3 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -873,6 +873,21 @@ spawnve (int mode, const char *path, const char *const *argv,
 {
   static char *const empty_env[] = { NULL };
 
+  /* Cygnal hack! If the path is "/bin/sh" and argv is of the three-element
+     form { "<name>", "-c", "<cmd>" } then let us rewrite argv to:
+     { "<path-to-cmd.exe>", "/c", "<cmd>" } and invoke "<path-to-cmd.exe>".
+     This will automatically "port" many programs that use hard-coded /bin/sh
+     for command execution. For instance, we can use the Cygwin-packaged
+     gawk.exe binary over Cygnal; awk pipes will work using cmd.exe.*/
+
+  if (argv[0] && argv[1] && argv[2] && !argv[3] &&
+      !strcmp(path, "/bin/sh") && !strcmp(argv[1], "-c"))
+    {
+      const char *argv_sub[3] = { get_cmd_exe_path(), "/c", argv[2] };
+      return spawnve (mode, argv_sub[0],
+		      const_cast<const char *const *>(argv_sub), envp);
+    }
+
   int ret;
 
   syscall_printf ("spawnve (%s, %s, %p)", path, argv[0], envp);