* external.cc (cygwin_internal): Export __cygwin_user_data.

* include/sys/cygwin.h: Allow definition of per_process even when not compiling
with C++.
(cygwin_getinfo_types): Add CW_USER_DATA.
* lib/_cygwin_crt0_common.cc (_cygwin_crt0_common): Get __cygwin_user_data
pointer from cygwin_internal.  If it doesn't exist, return failure.  Use either
this pointer or passed in pointer throughout.  Clear forkee.
* lib/crt0.h: Accomodate argument changes to _cygwin_crt0_common.
* lib/cygwin_attach_dll.c (cygwin_attach_dll): Reorganize to allow use of newer
binaries with older DLLs.  Detect older DLLs when _cygwin_crt0_common returns 0
and allocate space for a per_process structure on the stack.
* lib/cygwin_crt0.c (cygwin_crt0): Ditto.

4 files changed, 74 insertions, 39 deletions

diff --git a/winsup/cygwin/lib/_cygwin_crt0_common.cc b/winsup/cygwin/lib/_cygwin_crt0_common.cc
index 676d466..4ca6dd7 100644
--- a/winsup/cygwin/lib/_cygwin_crt0_common.cc
+++ b/winsup/cygwin/lib/_cygwin_crt0_common.cc
@@ -13,8 +13,6 @@ details. */
 #include <reent.h>
 #include <stdlib.h>
 
-extern __declspec(dllimport) per_process __cygwin_user_data;
-
 extern "C"
 {
 char **environ;
@@ -28,49 +26,70 @@ int _fmode;
 /* Set up pointers to various pieces so the dll can then use them,
    and then jump to the dll.  */
 
-void
-_cygwin_crt0_common (MainFunc f)
+int __stdcall
+_cygwin_crt0_common (MainFunc f, per_process *u)
 {
   /* This is used to record what the initial sp was.  The value is needed
      when copying the parent's stack to the child during a fork.  */
-  int onstack;
+  DWORD newu;
+  int uwasnull;
+
+  if (u != NULL)
+    uwasnull = 0;	/* Caller allocated space for per_process structure */
+  else if ((newu = cygwin_internal (CW_USER_DATA)) == (DWORD) -1)
+    return 0;
+  else
+    {
+      u = (per_process *) newu;	/* Using DLL built-in per_process */
+      uwasnull = 1;	/* Remember for later */
+    }
 
   /* The version numbers are the main source of compatibility checking.
      As a backup to them, we use the size of the per_process struct.  */
-  __cygwin_user_data.magic_biscuit = sizeof (per_process);
+  u->magic_biscuit = sizeof (per_process);
 
   /* cygwin.dll version number in effect at the time the app was created.  */
-  __cygwin_user_data.dll_major = CYGWIN_VERSION_DLL_MAJOR;
-  __cygwin_user_data.dll_minor = CYGWIN_VERSION_DLL_MINOR;
-  __cygwin_user_data.api_major = CYGWIN_VERSION_API_MAJOR;
-  __cygwin_user_data.api_minor = CYGWIN_VERSION_API_MINOR;
+  u->dll_major = CYGWIN_VERSION_DLL_MAJOR;
+  u->dll_minor = CYGWIN_VERSION_DLL_MINOR;
+  u->api_major = CYGWIN_VERSION_API_MAJOR;
+  u->api_minor = CYGWIN_VERSION_API_MINOR;
+
+  u->ctors = &__CTOR_LIST__;
+  u->dtors = &__DTOR_LIST__;
+  u->envptr = &environ;
+  if (uwasnull)
+    _impure_ptr = u->impure_ptr;	/* Use field initialized in newer DLLs. */
+  else
+    u->impure_ptr_ptr = &_impure_ptr;	/* Older DLLs need this. */
+      
+  u->forkee = 0;			/* This should only be set in dcrt0.cc
+					   when the process is actually forked */
+  u->main = f;
 
-  __cygwin_user_data.ctors = &__CTOR_LIST__;
-  __cygwin_user_data.dtors = &__DTOR_LIST__;
-  __cygwin_user_data.envptr = &environ;
-  _impure_ptr = __cygwin_user_data.impure_ptr;
-  __cygwin_user_data.main = f;
-  __cygwin_user_data.premain[0] = cygwin_premain0;
-  __cygwin_user_data.premain[1] = cygwin_premain1;
-  __cygwin_user_data.premain[2] = cygwin_premain2;
-  __cygwin_user_data.premain[3] = cygwin_premain3;
-  __cygwin_user_data.fmode_ptr = &_fmode;
-  __cygwin_user_data.initial_sp = (char *) &onstack;
+  /* These functions are executed prior to main.  They are just stubs unless the
+     user overrides them. */
+  u->premain[0] = cygwin_premain0;
+  u->premain[1] = cygwin_premain1;
+  u->premain[2] = cygwin_premain2;
+  u->premain[3] = cygwin_premain3;
+  u->fmode_ptr = &_fmode;
+  u->initial_sp = (char *) __builtin_frame_address (1);
 
   /* Remember whatever the user linked his application with - or
      point to entries in the dll.  */
-  __cygwin_user_data.malloc = &malloc;
-  __cygwin_user_data.free = &free;
-  __cygwin_user_data.realloc = &realloc;
-  __cygwin_user_data.calloc = &calloc;
+  u->malloc = &malloc;
+  u->free = &free;
+  u->realloc = &realloc;
+  u->calloc = &calloc;
 
   /* Setup the module handle so fork can get the path name. */
-  __cygwin_user_data.hmodule = GetModuleHandle (0);
+  u->hmodule = GetModuleHandle (0);
 
   /* variables for fork */
-  __cygwin_user_data.data_start = &_data_start__;
-  __cygwin_user_data.data_end = &_data_end__;
-  __cygwin_user_data.bss_start = &_bss_start__;
-  __cygwin_user_data.bss_end = &_bss_end__;
+  u->data_start = &_data_start__;
+  u->data_end = &_data_end__;
+  u->bss_start = &_bss_start__;
+  u->bss_end = &_bss_end__;
+  return 1;
 }
 } /* "C" */
diff --git a/winsup/cygwin/lib/crt0.h b/winsup/cygwin/lib/crt0.h
index 74c2c4b..523eedf 100644
--- a/winsup/cygwin/lib/crt0.h
+++ b/winsup/cygwin/lib/crt0.h
@@ -14,7 +14,7 @@ extern "C" {
 
 struct per_process;
 typedef int (*MainFunc) (int argc, char *argv[], char **env);
-void _cygwin_crt0_common (MainFunc);
+int __stdcall _cygwin_crt0_common (MainFunc, struct per_process *);
 int dll_dllcrt0 (HMODULE, struct per_process *);
 
 #ifdef __cplusplus
diff --git a/winsup/cygwin/lib/cygwin_attach_dll.c b/winsup/cygwin/lib/cygwin_attach_dll.c
index 18d9d7f..09b898b 100644
--- a/winsup/cygwin/lib/cygwin_attach_dll.c
+++ b/winsup/cygwin/lib/cygwin_attach_dll.c
@@ -8,15 +8,24 @@ This software is a copyrighted work licensed under the terms of the
 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
 details. */
 
+#undef __INSIDE_CYGWIN__
 #include <windows.h>
+#include <sys/cygwin.h>
 #include "crt0.h"
 
 /* for a loaded dll */
 int
 cygwin_attach_dll (HMODULE h, MainFunc f)
 {
-  _cygwin_crt0_common (f);
+  struct per_process *u;
+  if (_cygwin_crt0_common (f, NULL))
+    u = NULL;		/* Newer DLL.  Use DLL internal per_process. */
+  else			/* Older DLL.  Provide a per_process */
+    {
+      u = (struct per_process *) alloca (sizeof (*u));
+      (void) _cygwin_crt0_common (f, u);
+    }
 
   /* jump into the dll. */
-  return dll_dllcrt0 (h, NULL);
+  return dll_dllcrt0 (h, u);
 }
diff --git a/winsup/cygwin/lib/cygwin_crt0.c b/winsup/cygwin/lib/cygwin_crt0.c
index f0656a1..785d9f1 100644
--- a/winsup/cygwin/lib/cygwin_crt0.c
+++ b/winsup/cygwin/lib/cygwin_crt0.c
@@ -1,4 +1,4 @@
-/* crt0.cc: crt0 for libc
+/* cygwin_crt0.cc: crt0 for cygwin
 
    Copyright 2000 Cygnus Solutions.
 
@@ -8,17 +8,24 @@ This software is a copyrighted work licensed under the terms of the
 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
 details. */
 
+#undef __INSIDE_CYGWIN__
 #include <windows.h>
+#include <sys/cygwin.h>
 #include "crt0.h"
 
-extern void __stdcall _dll_crt0 (void)  __declspec (dllimport) __attribute ((noreturn));
+extern void dll_crt0__FP11per_process (struct per_process *)  __declspec (dllimport) __attribute ((noreturn));
 
 /* for main module */
 void
 cygwin_crt0 (MainFunc f)
 {
-  _cygwin_crt0_common (f);
-
- /* Jump into the dll. */
-  _dll_crt0 ();
+  struct per_process *u;
+  if (_cygwin_crt0_common (f, NULL))
+    u = NULL;		/* Newer DLL.  Use DLL internal per_process. */
+  else			/* Older DLL.  Provide a per_process */
+    {
+      u = (struct per_process *) alloca (sizeof (*u));
+      (void) _cygwin_crt0_common (f, u);
+    }
+  dll_crt0__FP11per_process (u); 	/* Jump into the dll, never to return */
 }