update for HEAD-2003050101

[reactos.git] / lib / epsapi / enum / drivers.c

diff --git a/lib/epsapi/enum/drivers.c b/lib/epsapi/enum/drivers.c
new file mode 100644 (file)
index 0000000..e2893b1
--- /dev/null
+++ b/lib/epsapi/enum/drivers.c
@@ -0,0 +1,227 @@
+/* $Id$
+*/
+/*
+ * COPYRIGHT:   See COPYING in the top level directory
+ * LICENSE:     See LGPL.txt in the top level directory
+ * PROJECT:     ReactOS system libraries
+ * FILE:        reactos/lib/epsapi/enum/drivers.c
+ * PURPOSE:     Enumerate system modules
+ * PROGRAMMER:  KJK::Hyperion <noog@libero.it>
+ * UPDATE HISTORY:
+ *              02/04/2003: Created
+ *              12/04/2003: internal PSAPI renamed EPSAPI (Extended PSAPI) and
+ *                          isolated in its own library to clear the confusion
+ *                          and improve reusability
+ */
+
+#include <ddk/ntddk.h>
+#include <debug.h>
+#include <stddef.h>
+
+#include <epsapi.h>
+
+NTSTATUS
+NTAPI
+PsaEnumerateSystemModules
+(
+ IN PSYSMOD_ENUM_ROUTINE Callback,
+ IN OUT PVOID CallbackContext
+)
+{
+ register NTSTATUS nErrCode = STATUS_SUCCESS;
+ PSYSTEM_MODULES psmModules = NULL;
+
+#if 0
+ __try
+ {
+#endif
+  do
+  {
+   /* capture the system modules */
+   nErrCode = PsaCaptureSystemModules(&psmModules);
+   
+   if(!NT_SUCCESS(nErrCode))
+    /* failure */
+    break;
+ 
+   /* walk the system modules */
+   nErrCode = PsaWalkSystemModules(psmModules, Callback, CallbackContext);
+  }
+  while(0);
+#if 0
+ }
+ __finally
+ {
+#endif
+  /* free the capture */
+  PsaFreeCapture(psmModules);
+#if 0
+ }
+#endif
+ 
+ /* return the last status */
+ return nErrCode;
+}
+
+NTSTATUS
+NTAPI
+PsaCaptureSystemModules
+(
+ OUT PSYSTEM_MODULES * SystemModules
+)
+{
+ SIZE_T nSize = 0;
+ register NTSTATUS nErrCode;
+ register PSYSTEM_MODULES psmModules = (PSYSTEM_MODULES)&nSize;
+
+#if 0
+ __try
+ {
+#endif
+  do
+  {
+   /* initial probe. We just get the count of system modules */
+   nErrCode = NtQuerySystemInformation
+   (
+    SystemModuleInformation,
+    psmModules,
+    sizeof(nSize),
+    NULL
+   );
+
+   if(nErrCode != STATUS_INFO_LENGTH_MISMATCH && !NT_SUCCESS(nErrCode))
+   {
+    /* failure */
+    DPRINT(FAILED_WITH_STATUS, "NtQuerySystemInformation", nErrCode);
+    break;
+   }
+
+   /* RATIONALE: the loading of a system module is a rare occurrence. To
+      minimize memory operations that could be expensive, or fragment the
+      pool/heap, we try to determine the buffer size in advance, knowing that
+      the number of elements is unlikely to change */
+   nSize =
+    sizeof(*psmModules) +
+    (psmModules->Count - 1) * sizeof(SYSTEM_MODULE_INFORMATION);
+
+   psmModules = NULL;
+
+   do
+   {
+    register void * pTmp;
+  
+    /* free the buffer, and reallocate it to the new size. RATIONALE: since we
+       ignore the buffer's content at this point, there's no point in a realloc,
+       that could end up copying a large chunk of data we'd discard anyway */
+    PsaiFree(psmModules);
+    pTmp = PsaiMalloc(nSize);
+    
+    if(pTmp == NULL)
+    {
+     /* failure */
+     nErrCode = STATUS_NO_MEMORY;
+     DPRINT(FAILED_WITH_STATUS, "PsaiMalloc", nErrCode);
+     break;
+    }
+
+    psmModules = pTmp;
+
+    /* query the information */
+    nErrCode = NtQuerySystemInformation
+    (
+     SystemModuleInformation,
+     psmModules,
+     nSize,
+     NULL
+    );
+
+    /* double the buffer for the next loop */
+    nSize += nSize;
+   }
+   /* repeat until the buffer is big enough */
+   while(nErrCode == STATUS_INFO_LENGTH_MISMATCH);
+
+   if(!NT_SUCCESS(nErrCode))
+   {
+    /* failure */
+    DPRINT(FAILED_WITH_STATUS, "NtQuerySystemInformation", nErrCode);
+    break;
+   }
+
+   /* success */
+   *SystemModules = psmModules;
+
+   nErrCode = STATUS_SUCCESS;
+  }
+  while(0);
+#if 0
+ }
+ __finally
+ {
+#endif
+  /* in case of failure, free the buffer */
+  if(!NT_SUCCESS(nErrCode))
+   PsaiFree(psmModules);
+#if 0
+ }
+#endif
+
+ /* return the last status */
+ return (nErrCode);
+}
+
+NTSTATUS
+NTAPI
+PsaWalkSystemModules
+(
+ IN PSYSTEM_MODULES SystemModules,
+ IN PSYSMOD_ENUM_ROUTINE Callback,
+ IN OUT PVOID CallbackContext
+)
+{
+ register NTSTATUS nErrCode;
+ register SIZE_T i;
+
+ /* repeat until all modules have been returned */
+ for(i = 0; i < SystemModules->Count; ++ i)
+ {
+  /* return current module to the callback */
+  nErrCode = Callback(&(SystemModules->Modules[i]), CallbackContext);
+  
+  if(!NT_SUCCESS(nErrCode))
+   /* failure */
+   return nErrCode;
+ }
+
+ /* success */
+ return STATUS_SUCCESS;
+}
+
+PSYSTEM_MODULE_INFORMATION
+FASTCALL
+PsaWalkFirstSystemModule
+(
+ IN PSYSTEM_MODULES SystemModules
+)
+{ 
+ return &(SystemModules->Modules[0]);
+}
+
+PSYSTEM_MODULE_INFORMATION
+FASTCALL
+PsaWalkNextSystemModule
+(
+ IN PSYSTEM_MODULE_INFORMATION CurrentSystemModule
+)
+{
+ return (PSYSTEM_MODULE_INFORMATION)
+ (
+  (ULONG_PTR)CurrentSystemModule +
+  (
+   offsetof(SYSTEM_MODULES, Modules[1]) -
+   offsetof(SYSTEM_MODULES, Modules[0])
+  )
+ );
+}
+
+/* EOF */