reactos/lib/epsapi/enum/drivers.c

   1 /* $Id$
   2 */
   3 /*
   4  * COPYRIGHT:   See COPYING in the top level directory
   5  * LICENSE:     See LGPL.txt in the top level directory
   6  * PROJECT:     ReactOS system libraries
   7  * FILE:        reactos/lib/epsapi/enum/drivers.c
   8  * PURPOSE:     Enumerate system modules
   9  * PROGRAMMER:  KJK::Hyperion <noog@libero.it>
  10  * UPDATE HISTORY:
  11  *              02/04/2003: Created
  12  *              12/04/2003: internal PSAPI renamed EPSAPI (Extended PSAPI) and
  13  *                          isolated in its own library to clear the confusion
  14  *                          and improve reusability
  15  */
  16
  17 #include <stddef.h>
  18 #define NTOS_MODE_USER
  19 #include <ntos.h>
  20
  21 #define NDEBUG
  22 #include <debug.h>
  23
  24 #include <epsapi.h>
  25
  26 NTSTATUS NTAPI
  27 PsaEnumerateSystemModules(IN PSYSMOD_ENUM_ROUTINE Callback,
  28                           IN OUT PVOID CallbackContext)
  29 {
  30   PSYSTEM_MODULE_INFORMATION psmModules;
  31   NTSTATUS Status = STATUS_SUCCESS;
  32
  33 #if 0
  34   __try
  35   {
  36 #else
  37   do
  38   {
  39 #endif
  40   /* capture the system modules */
  41   Status = PsaCaptureSystemModules(&psmModules);
  42
  43   if(!NT_SUCCESS(Status))
  44   {
  45     break;
  46   }
  47
  48   /* walk the system modules */
  49   Status = PsaWalkSystemModules(psmModules, Callback, CallbackContext);
  50 #if 0
  51   }
  52   __finally
  53   {
  54 #else
  55   } while(0);
  56 #endif
  57   /* free the capture */
  58   PsaFreeCapture(psmModules);
  59 #if 0
  60   }
  61 #endif
  62
  63   return Status;
  64 }
  65
  66 NTSTATUS NTAPI
  67 PsaCaptureSystemModules(OUT PSYSTEM_MODULE_INFORMATION *SystemModules)
  68 {
  69   SIZE_T nSize = 0;
  70   PSYSTEM_MODULE_INFORMATION psmModules;
  71   NTSTATUS Status;
  72
  73 #if 0
  74   __try
  75   {
  76 #else
  77   do
  78   {
  79 #endif
  80   /* initial probe. We just get the count of system modules */
  81   Status = NtQuerySystemInformation(SystemModuleInformation,
  82                                     &nSize,
  83                                     sizeof(nSize),
  84                                     NULL);
  85
  86   if(!NT_SUCCESS(Status) && (Status != STATUS_INFO_LENGTH_MISMATCH))
  87   {
  88     DPRINT(FAILED_WITH_STATUS, "NtQuerySystemInformation", Status);
  89     break;
  90   }
  91
  92   /* RATIONALE: the loading of a system module is a rare occurrence. To
  93      minimize memory operations that could be expensive, or fragment the
  94      pool/heap, we try to determine the buffer size in advance, knowing that
  95      the number of elements is unlikely to change */
  96   nSize = sizeof(SYSTEM_MODULE_INFORMATION) +
  97           ((psmModules->Count - 1) * sizeof(SYSTEM_MODULE_INFORMATION));
  98
  99   psmModules = NULL;
 100
 101   do
 102   {
 103     PVOID pTmp;
 104
 105     /* free the buffer, and reallocate it to the new size. RATIONALE: since we
 106        ignore the buffer's content at this point, there's no point in a realloc,
 107        that could end up copying a large chunk of data we'd discard anyway */
 108     PsaiFree(psmModules);
 109     pTmp = PsaiMalloc(nSize);
 110
 111     if(pTmp == NULL)
 112     {
 113       Status = STATUS_NO_MEMORY;
 114       DPRINT(FAILED_WITH_STATUS, "PsaiMalloc", Status);
 115       break;
 116     }
 117
 118     psmModules = pTmp;
 119
 120     /* query the information */
 121     Status = NtQuerySystemInformation(SystemModuleInformation,
 122                                       psmModules,
 123                                       nSize,
 124                                       NULL);
 125
 126     /* double the buffer for the next loop */
 127     nSize *= 2;
 128   } while(Status == STATUS_INFO_LENGTH_MISMATCH);
 129
 130   if(!NT_SUCCESS(Status))
 131   {
 132     DPRINT(FAILED_WITH_STATUS, "NtQuerySystemInformation", Status);
 133     break;
 134   }
 135
 136   *SystemModules = psmModules;
 137
 138   Status = STATUS_SUCCESS;
 139 #if 0
 140   }
 141   __finally
 142   {
 143 #else
 144   } while(0);
 145 #endif
 146   /* in case of failure, free the buffer */
 147   if(!NT_SUCCESS(Status))
 148   {
 149     PsaiFree(psmModules);
 150   }
 151 #if 0
 152   }
 153 #endif
 154
 155   return Status;
 156 }
 157
 158 NTSTATUS NTAPI
 159 PsaWalkSystemModules(IN PSYSTEM_MODULE_INFORMATION SystemModules,
 160                      IN PSYSMOD_ENUM_ROUTINE Callback,
 161                      IN OUT PVOID CallbackContext)
 162 {
 163   ULONG i;
 164   NTSTATUS Status;
 165
 166   /* repeat until all modules have been returned */
 167   for(i = 0; i < SystemModules->Count; i++)
 168   {
 169     /* return current module to the callback */
 170     Status = Callback(&(SystemModules->Module[i]), CallbackContext);
 171
 172     if(!NT_SUCCESS(Status))
 173     {
 174       return Status;
 175     }
 176   }
 177
 178   return STATUS_SUCCESS;
 179 }
 180
 181 PSYSTEM_MODULE_INFORMATION_ENTRY FASTCALL
 182 PsaWalkFirstSystemModule(IN PSYSTEM_MODULE_INFORMATION SystemModules)
 183 {
 184   return &(SystemModules->Module[0]);
 185 }
 186
 187 PSYSTEM_MODULE_INFORMATION_ENTRY FASTCALL
 188 PsaWalkNextSystemModule(IN PSYSTEM_MODULE_INFORMATION CurrentSystemModule)
 189 {
 190   return (PSYSTEM_MODULE_INFORMATION_ENTRY)((ULONG_PTR)CurrentSystemModule +
 191                                             (offsetof(SYSTEM_MODULE_INFORMATION, Module[1]) -
 192                                              offsetof(SYSTEM_MODULE_INFORMATION, Module[0])));
 193 }
 194
 195 /* EOF */