lib/epsapi/enum/drivers.c

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