[PATCH 2/6] dll_list: Track main executable and cygwin1.dll.

[Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>]

Even for the main executable and cygwin1.dll store the file name as full
NT path.  Create the child process using the main executable's file name
converted from the full NT path stored before.

	* dll_init.cc (dll_list::alloc): Search for DLL_SELF type entry
	with module name like for DLL_LINK, use full NT path to search
	for DLL_LOAD type only.  For DLL_SELF type do not indicate
	having a destructor to be called.
	(dll_list::find): Ignore DLL_SELF type entries.
	(dll_list::init): Ditto.  Call track_self method.
	(dll_list::track_self): New.
	(dll_list::load_after_fork): Call track_self method.
	* dll_init.h (enum dll_type): Add DLL_SELF, for the main
	executable and cygwin1.dll.
	(struct dll_list): Declare private method track_self.  Declare
	member variable main_executable.
	* fork.cc (frok::parent): Use ntname from dlls.main_executable
	to create child process, converted to short path using
	dll_list::buffered_shortname.
---
 winsup/cygwin/dll_init.cc | 26 ++++++++++++++++++++------
 winsup/cygwin/dll_init.h  |  4 ++++
 winsup/cygwin/fork.cc     | 15 ++++++++++++---
 3 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/winsup/cygwin/dll_init.cc b/winsup/cygwin/dll_init.cc
index 6bdd437..8c208d5 100644
--- a/winsup/cygwin/dll_init.cc
+++ b/winsup/cygwin/dll_init.cc
@@ -307,8 +307,9 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type)
   guard (true);
   /* Already loaded?  For linked DLLs, only compare the basenames.  Linked
      DLLs are loaded using just the basename and the default DLL search path.
-     The Windows loader picks up the first one it finds.  */
-  dll *d = (type == DLL_LINK) ? dlls.find_by_modname (modname) : dlls[ntname];
+     The Windows loader picks up the first one it finds.
+     This also applies to cygwin1.dll and the main-executable (DLL_SELF).  */
+  dll *d = (type != DLL_LOAD) ? dlls.find_by_modname (modname) : dlls[ntname];
   if (d)
     {
       if (!in_forkee)
@@ -344,7 +345,8 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type)
       wcscpy (d->ntname, ntname);
       d->modname = d->ntname + (modname - ntname);
       d->handle = h;
-      d->has_dtors = true;
+      /* DLL_SELF dtors (main-executable, cygwin1.dll) are run elsewhere */
+      d->has_dtors = type != DLL_SELF;
       d->p = p;
       d->ndeps = 0;
       d->deps = NULL;
@@ -488,7 +490,7 @@ dll_list::find (void *retaddr)
 
   dll *d = &start;
   while ((d = d->next))
-    if (d->handle == h)
+    if (d->type != DLL_SELF && d->handle == h)
       break;
   return d;
 }
@@ -533,11 +535,22 @@ dll_list::detach (void *retaddr)
 void
 dll_list::init ()
 {
+  track_self ();
+
   /* Walk the dll chain, initializing each dll */
   dll *d = &start;
   dll_global_dtors_recorded = d->next != NULL;
   while ((d = d->next))
-    d->init ();
+    if (d->type != DLL_SELF) /* linked and early loaded dlls */
+      d->init ();
+}
+
+void
+dll_list::track_self ()
+{
+  /* for cygwin1.dll and main-executable: maintain hardlinks only */
+  alloc (cygwin_hmodule, user_data, DLL_SELF);
+  main_executable = alloc (GetModuleHandle (NULL), user_data, DLL_SELF);
 }
 
 #define A64K (64 * 1024)
@@ -604,7 +617,7 @@ dll_list::reserve_space ()
 
 /* Reload DLLs after a fork.  Iterates over the list of dynamically loaded
    DLLs and attempts to load them in the same place as they were loaded in the
-   parent. */
+   parent.  Updates main-executable and cygwin1.dll tracking. */
 void
 dll_list::load_after_fork (HANDLE parent)
 {
@@ -614,6 +627,7 @@ dll_list::load_after_fork (HANDLE parent)
   in_load_after_fork = true;
   if (reload_on_fork)
     load_after_fork_impl (parent, dlls.istart (DLL_LOAD), 0);
+  track_self ();
   in_load_after_fork = false;
 }
 
diff --git a/winsup/cygwin/dll_init.h b/winsup/cygwin/dll_init.h
index e85fdb1..a132adb 100644
--- a/winsup/cygwin/dll_init.h
+++ b/winsup/cygwin/dll_init.h
@@ -40,6 +40,7 @@ struct per_module
 typedef enum
 {
   DLL_NONE,
+  DLL_SELF, /* main-program.exe, cygwin1.dll */
   DLL_LINK,
   DLL_LOAD,
   DLL_ANY
@@ -75,6 +76,8 @@ struct dll
 
 class dll_list
 {
+  void track_self ();
+
   dll *end;
   dll *hold;
   dll_type hold_type;
@@ -94,6 +97,7 @@ public:
     return nt_max_path_buffer;
   }
 
+  dll *main_executable;
   dll start;
   int loaded_dlls;
   int reload_on_fork;
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index 86689b4..45c571b 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -181,7 +181,7 @@ frok::child (volatile char * volatile here)
   if (fixup_shms_after_fork ())
     api_fatal ("recreate_shm areas after fork failed");
 
-  /* load dynamic dlls, if any */
+  /* load dynamic dlls, if any, re-track main-executable and cygwin1.dll */
   dlls.load_after_fork (hParent);
 
   cygheap->fdtab.fixup_after_fork (hParent);
@@ -345,11 +345,20 @@ frok::parent (volatile char * volatile stack_here)
 
   while (1)
     {
+      PCWCHAR forking_progname = NULL;
+      if (dlls.main_executable)
+        forking_progname = dll_list::buffered_shortname
+			   (dlls.main_executable->ntname);
+      if (!forking_progname || !*forking_progname)
+	forking_progname = myself->progname;
+
       syscall_printf ("CreateProcessW (%W, %W, 0, 0, 1, %y, 0, 0, %p, %p)",
-		      myself->progname, myself->progname, c_flags, &si, &pi);
+		      forking_progname, myself->progname, c_flags, &si, &pi);
 
       hchild = NULL;
-      rc = CreateProcessW (myself->progname,	/* image to run */
+      /* cygwin1.dll may reuse the forking_progname buffer, even
+	 in case of failure: don't reuse forking_progname later */
+      rc = CreateProcessW (forking_progname,	/* image to run */
 			   GetCommandLineW (),	/* Take same space for command
 						   line as in parent to make
 						   sure child stack is allocated
-- 
2.7.3