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     pTmp = PsaiMalloc(nSize);
 104
 105     if(pTmp == NULL)
 106     {
 107       Status = STATUS_NO_MEMORY;
 108       DPRINT(FAILED_WITH_STATUS, "PsaiMalloc", Status);
 109       break;
 110     }
 111
 112     psmModules = pTmp;
 113
 114     /* query the information */
 115     Status = NtQuerySystemInformation(SystemModuleInformation,
 116                                       psmModules,
 117                                       nSize,
 118                                       NULL);
 119
 120     /* double the buffer for the next loop */
 121     nSize *= 2;
 122   } while(Status == STATUS_INFO_LENGTH_MISMATCH);
 123
 124   if(!NT_SUCCESS(Status))
 125   {
 126     DPRINT(FAILED_WITH_STATUS, "NtQuerySystemInformation", Status);
 127     break;
 128   }
 129
 130   *SystemModules = psmModules;
 131
 132   Status = STATUS_SUCCESS;
 133 #if 0
 134   }
 135   __finally
 136   {
 137 #else
 138   } while(0);
 139 #endif
 140   /* in case of failure, free the buffer */
 141   if(!NT_SUCCESS(Status))
 142   {
 143     PsaiFree(psmModules);
 144   }
 145 #if 0
 146   }
 147 #endif
 148
 149   return Status;
 150 }
 151
 152 NTSTATUS NTAPI
 153 PsaWalkSystemModules(IN PRTL_PROCESS_MODULES SystemModules,
 154                      IN PSYSMOD_ENUM_ROUTINE Callback,
 155                      IN OUT PVOID CallbackContext)
 156 {
 157   ULONG i;
 158   NTSTATUS Status;
 159
 160   /* repeat until all modules have been returned */
 161   for(i = 0; i < SystemModules->NumberOfModules; i++)
 162   {
 163     /* return current module to the callback */
 164     Status = Callback(&(SystemModules->Modules[i]), CallbackContext);
 165
 166     if(!NT_SUCCESS(Status))
 167     {
 168       return Status;
 169     }
 170   }
 171
 172   return STATUS_SUCCESS;
 173 }
 174
 175 PRTL_PROCESS_MODULE_INFORMATION FASTCALL
 176 PsaWalkFirstSystemModule(IN PRTL_PROCESS_MODULES SystemModules)
 177 {
 178   return &(SystemModules->Modules[0]);
 179 }
 180
 181 PRTL_PROCESS_MODULE_INFORMATION FASTCALL
 182 PsaWalkNextSystemModule(IN PRTL_PROCESS_MODULES CurrentSystemModule)
 183 {
 184   return (PRTL_PROCESS_MODULE_INFORMATION)((ULONG_PTR)CurrentSystemModule +
 185                                             (FIELD_OFFSET(RTL_PROCESS_MODULES, Modules[1]) -
 186                                              FIELD_OFFSET(RTL_PROCESS_MODULES, Modules[0])));
 187 }
 188
 189 /* EOF */