[PATCH 5/6] dbghelp: detect collision by looking at module's base address in SymLoadModuleEx()

[Eric Pouech]

this replaces existing collision detection which is based on module name

this ensures that there is no other module present at module's load address
(that's good as all modules are identified in dbghelp by their base address)

this allows loading twice the same module at different addresses (and
even two different modules yet with same module name like foo.dll and
foo.drv)

Signed-off-by: Eric Pouech <eric.pouech at gmail.com>

---
 dlls/dbghelp/module.c |   73 ++++++++++++++++++++++++++-----------------------
 1 file changed, 38 insertions(+), 35 deletions(-)

diff --git a/dlls/dbghelp/module.c b/dlls/dbghelp/module.c
index 5c439dd1d3c..64d4e3113d5 100644
--- a/dlls/dbghelp/module.c
+++ b/dlls/dbghelp/module.c
@@ -900,7 +900,8 @@ DWORD64 WINAPI  SymLoadModuleExW(HANDLE hProcess, HANDLE hFile, PCWSTR wImageNam
                                  PMODLOAD_DATA Data, DWORD Flags)
 {
     struct process*     pcs;
-    struct module*	module = NULL;
+    struct module*      module = NULL;
+    struct module*      altmodule;
 
     TRACE("(%p %p %s %s %s %08x %p %08x)\n",
           hProcess, hFile, debugstr_w(wImageName), debugstr_w(wModuleName),
@@ -912,16 +913,6 @@ DWORD64 WINAPI  SymLoadModuleExW(HANDLE hProcess, HANDLE hFile, PCWSTR wImageNam
 
     if (!(pcs = process_find_by_handle(hProcess))) return 0;
 
-    if (Flags & SLMFLAG_VIRTUAL)
-    {
-        if (!wImageName) return 0;
-        module = module_new(pcs, wImageName, DMT_PE, TRUE, BaseOfDll, SizeOfDll, 0, 0, IMAGE_FILE_MACHINE_UNKNOWN);
-        if (!module) return 0;
-        if (wModuleName) module_set_module(module, wModuleName);
-        module->module.SymType = SymVirtual;
-
-        return module->module.BaseOfImage;
-    }
     if (Flags & ~(SLMFLAG_VIRTUAL))
         FIXME("Unsupported Flags %08x for %s\n", Flags, debugstr_w(wImageName));
 
@@ -930,31 +921,18 @@ DWORD64 WINAPI  SymLoadModuleExW(HANDLE hProcess, HANDLE hFile, PCWSTR wImageNam
     /* this is a Wine extension to the API just to redo the synchronisation */
     if (!wImageName && !hFile) return 0;
 
-    /* check if the module is already loaded, or if it's a builtin PE module with
-     * an containing ELF module
-     */
-    if (wImageName)
+    if (Flags & SLMFLAG_VIRTUAL)
     {
-        module = module_is_already_loaded(pcs, wImageName);
-        if (module)
-        {
-            if (module->module.BaseOfImage == BaseOfDll)
-                SetLastError(ERROR_SUCCESS);
-            else
-            {
-                /* native allows to load the same module at different addresses
-                 * we don't support this for now
-                 */
-                SetLastError(ERROR_INVALID_PARAMETER);
-                FIXME("Reloading %s at different base address isn't supported\n", debugstr_w(module->modulename));
-            }
-            return 0;
-        }
-        if (!module && module_is_container_loaded(pcs, wImageName, BaseOfDll))
-        {
-            /* force the loading of DLL as builtin */
-            module = pe_load_builtin_module(pcs, wImageName, BaseOfDll, SizeOfDll);
-        }
+        if (!wImageName) return 0;
+        module = module_new(pcs, wImageName, DMT_PE, TRUE, BaseOfDll, SizeOfDll, 0, 0, IMAGE_FILE_MACHINE_UNKNOWN);
+        if (!module) return 0;
+        module->module.SymType = SymVirtual;
+    }
+    /* check if it's a builtin PE module with a containing ELF module */
+    else if (wImageName && module_is_container_loaded(pcs, wImageName, BaseOfDll))
+    {
+        /* force the loading of DLL as builtin */
+        module = pe_load_builtin_module(pcs, wImageName, BaseOfDll, SizeOfDll);
     }
     if (!module)
     {
@@ -978,6 +956,31 @@ DWORD64 WINAPI  SymLoadModuleExW(HANDLE hProcess, HANDLE hFile, PCWSTR wImageNam
         module_set_module(module, wModuleName);
     if (wImageName)
         lstrcpynW(module->module.ImageName, wImageName, ARRAY_SIZE(module->module.ImageName));
+
+    for (altmodule = pcs->lmodules; altmodule; altmodule = altmodule->next)
+    {
+        if (altmodule != module && altmodule->type == module->type &&
+            module->module.BaseOfImage >= altmodule->module.BaseOfImage &&
+            module->module.BaseOfImage < altmodule->module.BaseOfImage + altmodule->module.ImageSize)
+            break;
+    }
+    if (altmodule)
+    {
+        /* we have a conflict as the new module cannot be found by its base address
+         * we need to get rid of one on the two modules
+         */
+        /* loading same module at same address... don't change anything */
+        if (module->module.BaseOfImage == altmodule->module.BaseOfImage)
+        {
+            module_remove(pcs, module);
+            SetLastError(ERROR_SUCCESS);
+            return 0;
+        }
+        module_remove(pcs, module);
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return 0;
+    }
+
     if ((dbghelp_options & SYMOPT_DEFERRED_LOADS) == 0)
         module_load_debug(module);
     return module->module.BaseOfImage;