t/helper/test-drop-caches.c

   1 #include "git-compat-util.h"
   2
   3 #if defined(GIT_WINDOWS_NATIVE)
   4
   5 static int cmd_sync(void)
   6 {
   7         char Buffer[MAX_PATH];
   8         DWORD dwRet;
   9         char szVolumeAccessPath[] = "\\\\.\\XXXX:";
  10         HANDLE hVolWrite;
  11         int success = 0, dos_drive_prefix;
  12
  13         dwRet = GetCurrentDirectory(MAX_PATH, Buffer);
  14         if ((0 == dwRet) || (dwRet > MAX_PATH))
  15                 return error("Error getting current directory");
  16
  17         dos_drive_prefix = has_dos_drive_prefix(Buffer);
  18         if (!dos_drive_prefix)
  19                 return error("'%s': invalid drive letter", Buffer);
  20
  21         memcpy(szVolumeAccessPath, Buffer, dos_drive_prefix);
  22         szVolumeAccessPath[dos_drive_prefix] = '\0';
  23
  24         hVolWrite = CreateFile(szVolumeAccessPath, GENERIC_READ | GENERIC_WRITE,
  25                 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
  26         if (INVALID_HANDLE_VALUE == hVolWrite)
  27                 return error("Unable to open volume for writing, need admin access");
  28
  29         success = FlushFileBuffers(hVolWrite);
  30         if (!success)
  31                 error("Unable to flush volume");
  32
  33         CloseHandle(hVolWrite);
  34
  35         return !success;
  36 }
  37
  38 #define STATUS_SUCCESS                  (0x00000000L)
  39 #define STATUS_PRIVILEGE_NOT_HELD       (0xC0000061L)
  40
  41 typedef enum _SYSTEM_INFORMATION_CLASS {
  42         SystemMemoryListInformation = 80,
  43 } SYSTEM_INFORMATION_CLASS;
  44
  45 typedef enum _SYSTEM_MEMORY_LIST_COMMAND {
  46         MemoryCaptureAccessedBits,
  47         MemoryCaptureAndResetAccessedBits,
  48         MemoryEmptyWorkingSets,
  49         MemoryFlushModifiedList,
  50         MemoryPurgeStandbyList,
  51         MemoryPurgeLowPriorityStandbyList,
  52         MemoryCommandMax
  53 } SYSTEM_MEMORY_LIST_COMMAND;
  54
  55 static BOOL GetPrivilege(HANDLE TokenHandle, LPCSTR lpName, int flags)
  56 {
  57         BOOL bResult;
  58         DWORD dwBufferLength;
  59         LUID luid;
  60         TOKEN_PRIVILEGES tpPreviousState;
  61         TOKEN_PRIVILEGES tpNewState;
  62
  63         dwBufferLength = 16;
  64         bResult = LookupPrivilegeValueA(0, lpName, &luid);
  65         if (bResult) {
  66                 tpNewState.PrivilegeCount = 1;
  67                 tpNewState.Privileges[0].Luid = luid;
  68                 tpNewState.Privileges[0].Attributes = 0;
  69                 bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpNewState,
  70                         (DWORD)((LPBYTE)&(tpNewState.Privileges[1]) - (LPBYTE)&tpNewState),
  71                         &tpPreviousState, &dwBufferLength);
  72                 if (bResult) {
  73                         tpPreviousState.PrivilegeCount = 1;
  74                         tpPreviousState.Privileges[0].Luid = luid;
  75                         tpPreviousState.Privileges[0].Attributes = flags != 0 ? 2 : 0;
  76                         bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpPreviousState,
  77                                 dwBufferLength, 0, 0);
  78                 }
  79         }
  80         return bResult;
  81 }
  82
  83 static int cmd_dropcaches(void)
  84 {
  85         HANDLE hProcess = GetCurrentProcess();
  86         HANDLE hToken;
  87         HMODULE ntdll;
  88         DWORD(WINAPI *NtSetSystemInformation)(INT, PVOID, ULONG);
  89         SYSTEM_MEMORY_LIST_COMMAND command;
  90         int status;
  91
  92         if (!OpenProcessToken(hProcess, TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, &hToken))
  93                 return error("Can't open current process token");
  94
  95         if (!GetPrivilege(hToken, "SeProfileSingleProcessPrivilege", 1))
  96                 return error("Can't get SeProfileSingleProcessPrivilege");
  97
  98         CloseHandle(hToken);
  99
 100         ntdll = LoadLibrary("ntdll.dll");
 101         if (!ntdll)
 102                 return error("Can't load ntdll.dll, wrong Windows version?");
 103
 104         NtSetSystemInformation =
 105                 (DWORD(WINAPI *)(INT, PVOID, ULONG))GetProcAddress(ntdll, "NtSetSystemInformation");
 106         if (!NtSetSystemInformation)
 107                 return error("Can't get function addresses, wrong Windows version?");
 108
 109         command = MemoryPurgeStandbyList;
 110         status = NtSetSystemInformation(
 111                 SystemMemoryListInformation,
 112                 &command,
 113                 sizeof(SYSTEM_MEMORY_LIST_COMMAND)
 114         );
 115         if (status == STATUS_PRIVILEGE_NOT_HELD)
 116                 error("Insufficient privileges to purge the standby list, need admin access");
 117         else if (status != STATUS_SUCCESS)
 118                 error("Unable to execute the memory list command %d", status);
 119
 120         FreeLibrary(ntdll);
 121
 122         return status;
 123 }
 124
 125 #elif defined(__linux__)
 126
 127 static int cmd_sync(void)
 128 {
 129         return system("sync");
 130 }
 131
 132 static int cmd_dropcaches(void)
 133 {
 134         return system("echo 3 | sudo tee /proc/sys/vm/drop_caches");
 135 }
 136
 137 #elif defined(__APPLE__)
 138
 139 static int cmd_sync(void)
 140 {
 141         return system("sync");
 142 }
 143
 144 static int cmd_dropcaches(void)
 145 {
 146         return system("sudo purge");
 147 }
 148
 149 #else
 150
 151 static int cmd_sync(void)
 152 {
 153         return 0;
 154 }
 155
 156 static int cmd_dropcaches(void)
 157 {
 158         return error("drop caches not implemented on this platform");
 159 }
 160
 161 #endif
 162
 163 int cmd_main(int argc, const char **argv)
 164 {
 165         cmd_sync();
 166         return cmd_dropcaches();
 167 }