mirror of https://github.com/postgres/postgres
Hack things so that our idea of "struct stat" is equivalent to Windows' struct __stat64, allowing it to have a wide enough st_size field. Instead of relying on native stat(), use GetFileInformationByHandle(). This avoids a number of issues with Microsoft's multiple and rather slipshod emulations of stat(). We still need to jump through hoops to deal with ERROR_DELETE_PENDING, though :-( Pull the relevant support code out of dirmod.c and put it into its own file, win32stat.c. Still TODO: do we need to do something different with lstat(), rather than treating it identically to stat()? Juan José Santamaría Flecha, reviewed by Emil Iggland; based on prior work by Michael Paquier, Sergey Zubkovsky, and others Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905CF5099@g01jpexmbkw24 Discussion: https://postgr.es/m/15858-9572469fd3b73263@postgresql.orgpull/57/head
Tom Lane
5 years ago
parent
f13f2e4841
commit
bed90759fc
@ -0,0 +1,299 @@ |
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/*-------------------------------------------------------------------------
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* |
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* win32stat.c |
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* Replacements for <sys/stat.h> functions using GetFileInformationByHandle |
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* |
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* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group |
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* Portions Copyright (c) 1994, Regents of the University of California |
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* |
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* |
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* IDENTIFICATION |
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* src/port/win32stat.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifdef WIN32 |
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#include "c.h" |
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#include <windows.h> |
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/*
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* In order to support MinGW and MSVC2013 we use NtQueryInformationFile as an |
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* alternative for GetFileInformationByHandleEx. It is loaded from the ntdll |
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* library. |
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*/ |
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#if _WIN32_WINNT < 0x0600 |
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#include <winternl.h> |
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#if !defined(__MINGW32__) && !defined(__MINGW64__) |
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/* MinGW includes this in <winternl.h>, but it is missing in MSVC */ |
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typedef struct _FILE_STANDARD_INFORMATION |
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{ |
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LARGE_INTEGER AllocationSize; |
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LARGE_INTEGER EndOfFile; |
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ULONG NumberOfLinks; |
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BOOLEAN DeletePending; |
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BOOLEAN Directory; |
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} FILE_STANDARD_INFORMATION; |
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#define FileStandardInformation 5 |
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#endif /* !defined(__MINGW32__) && |
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* !defined(__MINGW64__) */ |
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typedef NTSTATUS(NTAPI * PFN_NTQUERYINFORMATIONFILE) |
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( |
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IN HANDLE FileHandle, |
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OUT PIO_STATUS_BLOCK IoStatusBlock, |
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OUT PVOID FileInformation, |
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IN ULONG Length, |
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IN FILE_INFORMATION_CLASS FileInformationClass |
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); |
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static PFN_NTQUERYINFORMATIONFILE _NtQueryInformationFile = NULL; |
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static HMODULE ntdll = NULL; |
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/*
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* Load DLL file just once regardless of how many functions we load/call in it. |
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*/ |
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static void |
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LoadNtdll(void) |
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{ |
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if (ntdll != NULL) |
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return; |
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ntdll = LoadLibraryEx("ntdll.dll", NULL, 0); |
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} |
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#endif /* _WIN32_WINNT < 0x0600 */ |
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/*
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* Convert a FILETIME struct into a 64 bit time_t. |
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*/ |
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static __time64_t |
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filetime_to_time(const FILETIME *ft) |
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{ |
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ULARGE_INTEGER unified_ft = {0}; |
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static const uint64 EpochShift = UINT64CONST(116444736000000000); |
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unified_ft.LowPart = ft->dwLowDateTime; |
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unified_ft.HighPart = ft->dwHighDateTime; |
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if (unified_ft.QuadPart < EpochShift) |
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return -1; |
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unified_ft.QuadPart -= EpochShift; |
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unified_ft.QuadPart /= 10 * 1000 * 1000; |
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return unified_ft.QuadPart; |
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} |
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/*
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* Convert WIN32 file attributes to a Unix-style mode. |
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* |
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* Only owner permissions are set. |
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*/ |
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static unsigned short |
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fileattr_to_unixmode(int attr) |
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{ |
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unsigned short uxmode = 0; |
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uxmode |= (unsigned short) ((attr & FILE_ATTRIBUTE_DIRECTORY) ? |
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(_S_IFDIR) : (_S_IFREG)); |
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uxmode |= (unsigned short) (attr & FILE_ATTRIBUTE_READONLY) ? |
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(_S_IREAD) : (_S_IREAD | _S_IWRITE); |
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/* there is no need to simulate _S_IEXEC using CMD's PATHEXT extensions */ |
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uxmode |= _S_IEXEC; |
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return uxmode; |
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} |
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/*
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* Convert WIN32 file information (from a HANDLE) to a struct stat. |
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*/ |
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static int |
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fileinfo_to_stat(HANDLE hFile, struct stat *buf) |
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{ |
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BY_HANDLE_FILE_INFORMATION fiData; |
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memset(buf, 0, sizeof(*buf)); |
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/*
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* GetFileInformationByHandle minimum supported version: Windows XP and |
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* Windows Server 2003, so it exists everywhere we care about. |
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*/ |
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if (!GetFileInformationByHandle(hFile, &fiData)) |
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{ |
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_dosmaperr(GetLastError()); |
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return -1; |
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} |
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if (fiData.ftLastWriteTime.dwLowDateTime || |
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fiData.ftLastWriteTime.dwHighDateTime) |
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buf->st_mtime = filetime_to_time(&fiData.ftLastWriteTime); |
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if (fiData.ftLastAccessTime.dwLowDateTime || |
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fiData.ftLastAccessTime.dwHighDateTime) |
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buf->st_atime = filetime_to_time(&fiData.ftLastAccessTime); |
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else |
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buf->st_atime = buf->st_mtime; |
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if (fiData.ftCreationTime.dwLowDateTime || |
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fiData.ftCreationTime.dwHighDateTime) |
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buf->st_ctime = filetime_to_time(&fiData.ftCreationTime); |
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else |
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buf->st_ctime = buf->st_mtime; |
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buf->st_mode = fileattr_to_unixmode(fiData.dwFileAttributes); |
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buf->st_nlink = fiData.nNumberOfLinks; |
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buf->st_size = (((uint64) fiData.nFileSizeHigh) << 32) | |
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(uint64) fiData.nFileSizeLow; |
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return 0; |
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} |
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/*
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* Windows implementation of stat(). |
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* |
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* This currently also implements lstat(), though perhaps that should change. |
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*/ |
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int |
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_pgstat64(const char *name, struct stat *buf) |
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{ |
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/*
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* We must use a handle so lstat() returns the information of the target |
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* file. To have a reliable test for ERROR_DELETE_PENDING, we use |
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* NtQueryInformationFile from Windows 2000 or |
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* GetFileInformationByHandleEx from Server 2008 / Vista. |
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*/ |
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SECURITY_ATTRIBUTES sa; |
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HANDLE hFile; |
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int ret; |
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#if _WIN32_WINNT < 0x0600 |
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IO_STATUS_BLOCK ioStatus; |
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FILE_STANDARD_INFORMATION standardInfo; |
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#else |
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FILE_STANDARD_INFO standardInfo; |
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#endif |
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if (name == NULL || buf == NULL) |
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{ |
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errno = EINVAL; |
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return -1; |
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} |
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/* fast not-exists check */ |
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if (GetFileAttributes(name) == INVALID_FILE_ATTRIBUTES) |
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{ |
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_dosmaperr(GetLastError()); |
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return -1; |
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} |
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/* get a file handle as lightweight as we can */ |
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sa.nLength = sizeof(SECURITY_ATTRIBUTES); |
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sa.bInheritHandle = TRUE; |
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sa.lpSecurityDescriptor = NULL; |
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hFile = CreateFile(name, |
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GENERIC_READ, |
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(FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE), |
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&sa, |
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OPEN_EXISTING, |
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(FILE_FLAG_NO_BUFFERING | FILE_FLAG_BACKUP_SEMANTICS | |
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FILE_FLAG_OVERLAPPED), |
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NULL); |
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if (hFile == INVALID_HANDLE_VALUE) |
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{ |
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CloseHandle(hFile); |
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errno = ENOENT; |
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return -1; |
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} |
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memset(&standardInfo, 0, sizeof(standardInfo)); |
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#if _WIN32_WINNT < 0x0600 |
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if (_NtQueryInformationFile == NULL) |
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{ |
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/* First time through: load ntdll.dll and find NtQueryInformationFile */ |
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LoadNtdll(); |
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if (ntdll == NULL) |
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{ |
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_dosmaperr(GetLastError()); |
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CloseHandle(hFile); |
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return -1; |
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} |
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_NtQueryInformationFile = (PFN_NTQUERYINFORMATIONFILE) |
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GetProcAddress(ntdll, "NtQueryInformationFile"); |
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if (_NtQueryInformationFile == NULL) |
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{ |
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_dosmaperr(GetLastError()); |
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CloseHandle(hFile); |
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return -1; |
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} |
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} |
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if (!NT_SUCCESS(_NtQueryInformationFile(hFile, &ioStatus, &standardInfo, |
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sizeof(standardInfo), |
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FileStandardInformation))) |
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{ |
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_dosmaperr(GetLastError()); |
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CloseHandle(hFile); |
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return -1; |
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} |
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#else |
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if (!GetFileInformationByHandleEx(hFile, FileStandardInfo, &standardInfo, |
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sizeof(standardInfo))) |
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{ |
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_dosmaperr(GetLastError()); |
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CloseHandle(hFile); |
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return -1; |
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} |
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#endif /* _WIN32_WINNT < 0x0600 */ |
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if (standardInfo.DeletePending) |
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{ |
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/*
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* File has been deleted, but is not gone from the filesystem yet. |
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* This can happen when some process with FILE_SHARE_DELETE has it |
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* open, and it will be fully removed once that handle is closed. |
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* Meanwhile, we can't open it, so indicate that the file just doesn't |
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* exist. |
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*/ |
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CloseHandle(hFile); |
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errno = ENOENT; |
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return -1; |
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} |
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/* At last we can invoke fileinfo_to_stat */ |
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ret = fileinfo_to_stat(hFile, buf); |
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CloseHandle(hFile); |
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return ret; |
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} |
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/*
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* Windows implementation of fstat(). |
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*/ |
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int |
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_pgfstat64(int fileno, struct stat *buf) |
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{ |
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HANDLE hFile = (HANDLE) _get_osfhandle(fileno); |
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if (hFile == INVALID_HANDLE_VALUE || buf == NULL) |
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{ |
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errno = EINVAL; |
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return -1; |
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} |
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/*
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* Since we already have a file handle there is no need to check for |
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* ERROR_DELETE_PENDING. |
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*/ |
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return fileinfo_to_stat(hFile, buf); |
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} |
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#endif /* WIN32 */ |
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Loading…
Reference in new issue