a923e21631
Calling fseek() or ftello() on a handle to a non-seeking device such as
a pipe or a communications device is not supported. Unfortunately,
MSVC's flavor of these routines, _fseeki64() and _ftelli64(), do not
return an error when given a pipe as handle. Some of the logic of
pg_dump and restore relies on these routines to check if a handle is
seekable, causing failures when passing the contents of pg_dump to
pg_restore through a pipe, for example.
This commit introduces wrappers for fseeko() and ftello() on MSVC so as
any callers are able to properly detect the cases of non-seekable
handles. This relies mainly on GetFileType(), sharing a bit of code
with the MSVC port for fstat(). The code in charge of getting a file
type is refactored into a new file called win32common.c, shared by
win32stat.c and the new win32fseek.c. It includes the MSVC ports for
fseeko() and ftello().
Like 765f5df, this is backpatched down to 14, where the fstat()
implementation for MSVC is able to understand about files larger than
4GB in size. Using a TAP test for that is proving to be tricky as
IPC::Run handles the pipes by itself, still I have been able to check
the fix manually.
Reported-by: Daniel Watzinger
Author: Juan José Santamaría Flecha, Michael Paquier
Discussion: https://postgr.es/m/CAC+AXB26a4EmxM2suXxPpJaGrqAdxracd7hskLg-zxtPB50h7A@mail.gmail.com
Backpatch-through: 14
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* win32common.c
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* Common routines shared among the win32*.c ports.
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*
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* Portions Copyright (c) 1996-2023, 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/win32common.c
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*
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*-------------------------------------------------------------------------
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*/
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#ifdef FRONTEND
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#include "postgres_fe.h"
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#else
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#include "postgres.h"
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#endif
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#ifdef WIN32
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/*
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* pgwin32_get_file_type
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*
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* Convenience wrapper for GetFileType() with specific error handling for all the
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* port implementations. Returns the file type associated with a HANDLE.
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*
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* On error, sets errno with FILE_TYPE_UNKNOWN as file type.
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*/
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DWORD
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pgwin32_get_file_type(HANDLE hFile)
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{
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DWORD fileType = FILE_TYPE_UNKNOWN;
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DWORD lastError;
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errno = 0;
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/*
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* When stdin, stdout, and stderr aren't associated with a stream the
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* special value -2 is returned:
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* https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/get-osfhandle
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*/
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if (hFile == INVALID_HANDLE_VALUE || hFile == (HANDLE) -2)
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{
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errno = EINVAL;
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return FILE_TYPE_UNKNOWN;
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}
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fileType = GetFileType(hFile);
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lastError = GetLastError();
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/*
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* Invoke GetLastError in order to distinguish between a "valid" return of
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* FILE_TYPE_UNKNOWN and its return due to a calling error. In case of
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* success, GetLastError() returns NO_ERROR.
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*/
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if (fileType == FILE_TYPE_UNKNOWN && lastError != NO_ERROR)
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{
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_dosmaperr(lastError);
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return FILE_TYPE_UNKNOWN;
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}
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return fileType;
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}
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#endif /* WIN32 */
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