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