open.cpp File Reference

#include <corecrt_internal_lowio.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>

Include dependency graph for open.cpp:

Go to the source code of this file.

Classes
struct	anonymous_namespace{open.cpp}::file_options

Namespaces
namespace	anonymous_namespace{open.cpp}

Macros
#define	UTF16LE_BOM   0xFEFF
#define	UTF16BE_BOM   0xFFFE
#define	BOM_MASK   0xFFFF
#define	UTF8_BOM   0xBFBBEF
#define	UTF16_BOMLEN   2
#define	UTF8_BOMLEN   3

Functions
template<typename Character >
static int __cdecl	common_open (_In_z_ Character const *const path, int const oflag, int const pmode) throw ()
int	_open (char const *const path, int const oflag,...)
int	_wopen (wchar_t const *const path, int const oflag,...)
template<typename Character >
static errno_t __cdecl	common_sopen_dispatch (_In_z_ Character const *const path, int const oflag, int const shflag, int const pmode, int *const pfh, int const secure) throw ()
errno_t __cdecl	_sopen_dispatch (char const *const path, int const oflag, int const shflag, int const pmode, int *const pfh, int const secure)
errno_t __cdecl	_wsopen_dispatch (wchar_t const *const path, int const oflag, int const shflag, int const pmode, int *const pfh, int const secure)
static HANDLE __cdecl	create_file (PCWSTR const path, SECURITY_ATTRIBUTES *const security_attributes, file_options const options) throw ()
static DWORD	decode_access_flags (int const oflag) throw ()
static DWORD	decode_open_create_flags (int const oflag) throw ()
static DWORD	decode_sharing_flags (int const shflag, int const access) throw ()
static bool	is_text_mode (int const oflag) throw ()
static file_options	decode_options (int const oflag, int const shflag, int const pmode) throw ()
static errno_t	truncate_ctrl_z_if_present (int const fh) throw ()
static errno_t	configure_text_mode (int const fh, file_options const options, int oflag, __crt_lowio_text_mode &text_mode) throw ()
errno_t __cdecl	_wsopen_nolock (int *const punlock_flag, int *const pfh, wchar_t const *const path, int const oflag, int const shflag, int const pmode, int const secure)
errno_t __cdecl	_sopen_nolock (int *const punlock_flag, int *const pfh, char const *const path, int const oflag, int const shflag, int const pmode, int const secure)
int __cdecl	_sopen (char const *const path, int const oflag, int const shflag,...)
int __cdecl	_wsopen (wchar_t const *const path, int const oflag, int const shflag,...)
errno_t __cdecl	_sopen_s (int *const pfh, char const *const path, int const oflag, int const shflag, int const pmode)
errno_t __cdecl	_wsopen_s (int *const pfh, wchar_t const *const path, int const oflag, int const shflag, int const pmode)

Variables
DWORD const	anonymous_namespace{open.cpp}::GENERIC_READ_WRITE = (GENERIC_READ | GENERIC_WRITE)

Macro Definition Documentation

BOM_MASK

#define BOM_MASK   0xFFFF

Definition at line 78 of file open.cpp.

UTF16_BOMLEN

#define UTF16_BOMLEN   2

Definition at line 80 of file open.cpp.

UTF16BE_BOM

#define UTF16BE_BOM   0xFFFE

Definition at line 77 of file open.cpp.

UTF16LE_BOM

#define UTF16LE_BOM   0xFEFF

Definition at line 76 of file open.cpp.

UTF8_BOM

#define UTF8_BOM   0xBFBBEF

Definition at line 79 of file open.cpp.

UTF8_BOMLEN

#define UTF8_BOMLEN   3

Definition at line 81 of file open.cpp.

Function Documentation

_open()

int _open	(	char const *const	path,
		int const	oflag,
			...
	)

Definition at line 124 of file open.cpp.

{
    va_list arglist;
    va_start(arglist, oflag);
    int const pmode = va_arg(arglist, int);
    va_end(arglist);
 
    return common_open(path, oflag, pmode);
}

Referenced by _creat(), compat_open(), install_from_unix_file(), main(), rd_open_file(), rw(), test__popen(), test__sopen_s(), test_chsize(), test_file_write_read(), test_get_osfhandle(), test_ioinfo_flags(), test_setmode(), and tmpfile().

_sopen()

int __cdecl _sopen	(	char const *const	path,
		int const	oflag,
		int const	shflag,
			...
	)

Definition at line 859 of file open.cpp.

{
    va_list ap;
    va_start(ap, shflag);
    int const pmode = va_arg(ap, int);
    va_end(ap);
 
    // The last argument is 0 so thta the pmode is not validated in open_s:
    int fh = -1;
    errno_t const result = _sopen_dispatch(path, oflag, shflag, pmode, &fh, FALSE);
    return result ? -1 : fh;
}

Referenced by _open(), and test_get_osfhandle().

_sopen_dispatch()

errno_t __cdecl _sopen_dispatch	(	char const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode,
		int *const	pfh,
		int const	secure
	)

Definition at line 196 of file open.cpp.

{
    return common_sopen_dispatch(path, oflag, shflag, pmode, pfh, secure);
}

Referenced by _sopen(), _sopen_s(), and test__sopen_dispatch().

_sopen_nolock()

errno_t __cdecl _sopen_nolock	(	int *const	punlock_flag,
		int *const	pfh,
		char const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode,
		int const	secure
	)

Definition at line 835 of file open.cpp.

{
    // At this point we know path is not null already
    __crt_internal_win32_buffer<wchar_t> wide_path;
 
    errno_t const cvt = __acrt_mbs_to_wcs_cp(path, wide_path, __acrt_get_utf8_acp_compatibility_codepage());
 
    if (cvt != 0) {
        return -1;
    }
 
    return _wsopen_nolock(punlock_flag, pfh, wide_path.data(), oflag, shflag, pmode, secure);
}

_sopen_s()

errno_t __cdecl _sopen_s	(	int *const	pfh,
		char const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode
	)

Definition at line 887 of file open.cpp.

{
    // The last argument is 1 so that pmode is validated in open_s:
    return _sopen_dispatch(path, oflag, shflag, pmode, pfh, TRUE);
}

_wopen()

int _wopen	(	wchar_t const *const	path,
		int const	oflag,
			...
	)

Definition at line 134 of file open.cpp.

{
    va_list arglist;
    va_start(arglist, oflag);
    int const pmode = va_arg(arglist, int);
    va_end(arglist);
 
    return common_open(path, oflag, pmode);
}

Referenced by compat_open(), and gz_open().

_wsopen()

int __cdecl _wsopen	(	wchar_t const *const	path,
		int const	oflag,
		int const	shflag,
			...
	)

Definition at line 872 of file open.cpp.

{
    va_list ap;
    va_start(ap, shflag);
    int const pmode = va_arg(ap, int);
    va_end(ap);
 
    // The last argument is 0 so thta the pmode is not validated in open_s:
    int fh = -1;
    errno_t const result = _wsopen_dispatch(path, oflag, shflag, pmode, &fh, FALSE);
    return result ? -1 : fh;
}

_wsopen_dispatch()

errno_t __cdecl _wsopen_dispatch	(	wchar_t const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode,
		int *const	pfh,
		int const	secure
	)

Definition at line 208 of file open.cpp.

{
    return common_sopen_dispatch(path, oflag, shflag, pmode, pfh, secure);
}

Referenced by _wsopen(), and _wsopen_s().

_wsopen_nolock()

errno_t __cdecl _wsopen_nolock	(	int *const	punlock_flag,
		int *const	pfh,
		wchar_t const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode,
		int const	secure
	)

Definition at line 655 of file open.cpp.

{
    UNREFERENCED_PARAMETER(secure);
 
    // First, do the initial parse of the options.  The only thing that can fail
    // here is the parsing of the share options, in which case -1 is returned
    // and errno is set.
    file_options options = decode_options(oflag, shflag, pmode);
    if (options.share == static_cast<DWORD>(-1))
    {
        _doserrno = 0;
        *pfh = -1;
        return errno;
    }
 
    // Allocate the CRT file handle.  Note that if a handle is allocated, it is
    // locked when it is returned by the allocation function.  It is our caller's
    // responsibility to unlock the file handle (we do not unlock it before
    // returning).
    *pfh = _alloc_osfhnd();
    if (*pfh == -1)
    {
        _doserrno = 0;
        *pfh = -1;
        errno = EMFILE;
        return errno;
    }
 
    // Beyond this point, do not change *pfh, even if an error occurs.  Our
    // caller requires the handle in order to release its lock.
    *punlock_flag = 1;
 
 
 
    SECURITY_ATTRIBUTES security_attributes;
    security_attributes.nLength = sizeof(security_attributes);
    security_attributes.lpSecurityDescriptor = nullptr;
    security_attributes.bInheritHandle = (oflag & _O_NOINHERIT) == 0;
 
 
    // Try to open or create the file:
    HANDLE os_handle = create_file(path, &security_attributes, options);
    if (os_handle == INVALID_HANDLE_VALUE)
    {
        if ((options.access & GENERIC_READ_WRITE) == GENERIC_READ_WRITE && (oflag & _O_WRONLY))
        {
            // The call may have failed because we may be trying to open
            // something for reading that does not allow reading (e.g. a pipe or
            // a device).  So, we try again with just GENERIC_WRITE.  If this
            // succeeds, we will have to assume the default encoding because we
            // will have no way to read the BOM.
            options.access &= ~GENERIC_READ;
 
            os_handle = create_file(path, &security_attributes, options);
        }
    }
 
    if (os_handle == INVALID_HANDLE_VALUE)
    {
        // We failed to open the file.  We need to free the CRT file handle, but
        // we do not release the lock--our caller releases the lock.
        _osfile(*pfh) &= ~FOPEN;
        __acrt_errno_map_os_error(GetLastError());
        return errno;
    }
 
    // Find out what type of file this is (e.g., file, device, pipe, etc.)
    DWORD const file_type = GetFileType(os_handle);
 
    if (file_type == FILE_TYPE_UNKNOWN)
    {
        DWORD const last_error = GetLastError();
        __acrt_errno_map_os_error(last_error);
 
        _osfile(*pfh) &= ~FOPEN;
        CloseHandle(os_handle);
 
        // If GetFileType returns FILE_TYPE_UNKNOWN but doesn't fail, the file
        // type really is unknown.  This function is not designed to handle
        // unknown types of files, so we must return an error.
        if (last_error == ERROR_SUCCESS)
            errno = EACCES;
 
        return errno;
    }
 
    if (file_type == FILE_TYPE_CHAR)
    {
        options.crt_flags |= FDEV;
    }
    else if (file_type == FILE_TYPE_PIPE)
    {
        options.crt_flags |= FPIPE;
    }
 
    // The file is open and valid.  Set the OS handle:
    __acrt_lowio_set_os_handle(*pfh, reinterpret_cast<intptr_t>(os_handle));
 
 
    // Mark the handle as open, and store the flags we gathered so far:
    options.crt_flags |= FOPEN;
    _osfile(*pfh) = options.crt_flags;
 
 
    // The text mode is set to ANSI by default.  If we find a BOM, then we will
    // reset this to the appropriate type (this check happens below).
    _textmode(*pfh) = __crt_lowio_text_mode::ansi;
 
 
    // If the text mode file is opened for writing and allows reading, remove
    // any trailing Ctrl+Z character, if present, to ensure appending works:
    if (oflag & _O_RDWR)
    {
        errno_t const result = truncate_ctrl_z_if_present(*pfh);
        if (result != 0)
        {
            _close_nolock(*pfh);
            return result;
        }
    }
 
    // Configure the text mode:
    __crt_lowio_text_mode text_mode = __crt_lowio_text_mode::ansi;
    errno_t const text_mode_result = configure_text_mode(*pfh, options, oflag, text_mode);
    if (text_mode_result != 0)
    {
        _close_nolock(*pfh);
        return text_mode_result;
    }
 
    _textmode(*pfh)   = text_mode;
    _tm_unicode(*pfh) = (oflag & _O_WTEXT) != 0;
 
 
    // Set FAPPEND flag if appropriate. Don't do this for devices or pipes:
    if ((options.crt_flags & (FDEV | FPIPE)) == 0 && (oflag & _O_APPEND))
        _osfile(*pfh) |= FAPPEND;
 
 
    // Finally, if we were asked only to open the file with write access but we
    // opened it with read and write access in order to read the BOM, close the
    // file and re-open it with only write access:
    if ((options.access & GENERIC_READ_WRITE) == GENERIC_READ_WRITE && (oflag & _O_WRONLY))
    {
        CloseHandle(os_handle);
        options.access &= ~GENERIC_READ;
        os_handle = create_file(path, &security_attributes, options);
 
        if (os_handle == INVALID_HANDLE_VALUE)
        {
            // Note that we can't use the normal close function here because the
            // file isn't really open anymore.  We need only release the file
            // handle by unsetting the FOPEN flag:
            __acrt_errno_map_os_error(GetLastError());
            _osfile(*pfh) &= ~FOPEN;
            _free_osfhnd(*pfh);
            return errno;
        }
        else
        {
            // We were able to open the file successfully, set the file
            // handle in the _ioinfo structure, then we are done.  All
            // the options.crt_flags should have been set properly already.
            _osfhnd(*pfh) = reinterpret_cast<intptr_t>(os_handle);
        }
    }
 
    return 0; // Success!
}

Referenced by _sopen_nolock().

_wsopen_s()

errno_t __cdecl _wsopen_s	(	int *const	pfh,
		wchar_t const *const	path,
		int const	oflag,
		int const	shflag,
		int const	pmode
	)

Definition at line 899 of file open.cpp.

{
    // The last argument is 1 so that pmode is validated in open_s:
    return _wsopen_dispatch(path, oflag, shflag, pmode, pfh, TRUE);
}

common_open()

template<typename Character >

static int __cdecl common_open ( _In_z_ Character const *const  path, int const  oflag, int const  pmode  ) throw ( )

static

Definition at line 84 of file open.cpp.

{
    typedef __crt_char_traits<Character> traits;
 
    _VALIDATE_RETURN(path != nullptr, EINVAL, -1);
 
    int fh = -1;
    int unlock_flag = 0;
    errno_t error_code = 0;
    __try
    {
        error_code = traits::tsopen_nolock(&unlock_flag, &fh, path, oflag, _SH_DENYNO, pmode, 0);
    }
    __finally
    {
        if (unlock_flag)
        {
            if (error_code)
            {
                _osfile(fh) &= ~FOPEN;
            }
 
            __acrt_lowio_unlock_fh(fh);
        }
    }
    __endtry
 
    if (error_code != 0)
    {
        errno = error_code;
        return -1;
    }
 
    return fh;
}

Referenced by _open(), and _wopen().

common_sopen_dispatch()

template<typename Character >

static errno_t __cdecl common_sopen_dispatch ( _In_z_ Character const *const  path, int const  oflag, int const  shflag, int const  pmode, int *const  pfh, int const  secure  ) throw ( )

static

Definition at line 147 of file open.cpp.

{
    typedef __crt_char_traits<Character> traits;
 
    _VALIDATE_RETURN_ERRCODE(pfh != nullptr, EINVAL);
    *pfh = -1;
 
    _VALIDATE_RETURN_ERRCODE(path != nullptr, EINVAL);
 
    if(secure)
    {
        _VALIDATE_RETURN_ERRCODE((pmode & (~(_S_IREAD | _S_IWRITE))) == 0, EINVAL);
    }
 
 
    int unlock_flag = 0;
    errno_t error_code = 0;
    __try
    {
        error_code = traits::tsopen_nolock(&unlock_flag, pfh, path, oflag, shflag, pmode, secure);
    }
    __finally
    {
        if (unlock_flag)
        {
            if (error_code)
            {
                _osfile(*pfh) &= ~FOPEN;
            }
            __acrt_lowio_unlock_fh(*pfh);
        }
    }
    __endtry
 
    if (error_code != 0)
    {
        *pfh = -1;
    }
 
    return error_code;
}

Referenced by _sopen_dispatch(), and _wsopen_dispatch().

configure_text_mode()

static errno_t configure_text_mode ( int const  fh, file_options const  options, int  oflag, __crt_lowio_text_mode &  text_mode  ) throw ( )

static

Definition at line 441 of file open.cpp.

{
    // The text mode is ANSI by default:
    text_mode = __crt_lowio_text_mode::ansi;
 
    // If the file is open in binary mode, it gets the default text mode:
    if ((_osfile(fh) & FTEXT) == 0)
        return 0;
 
    // Set the default text mode per the oflag.  The BOM may change the default,
    // if one is present.  If oflag does not specify a text mode, use the _fmode
    // default:
    DWORD const text_mode_mask = (_O_TEXT | _O_WTEXT | _O_U16TEXT | _O_U8TEXT);
    if ((oflag & text_mode_mask) == 0)
    {
        int fmode = 0;
        _ERRCHECK(_get_fmode(&fmode));
 
        if ((fmode & text_mode_mask) == 0)
            oflag |= _O_TEXT; // Default to ANSI.
        else
            oflag |= fmode & text_mode_mask;
    }
 
    // Now oflags should be set to one of the text modes:
    _ASSERTE((oflag & text_mode_mask) != 0);
 
    switch (oflag & text_mode_mask)
    {
    case _O_TEXT:
        text_mode = __crt_lowio_text_mode::ansi;
        break;
 
    case _O_WTEXT:
    case _O_WTEXT | _O_TEXT:
        if ((oflag & (_O_WRONLY | _O_CREAT | _O_TRUNC)) == (_O_WRONLY | _O_CREAT | _O_TRUNC))
            text_mode = __crt_lowio_text_mode::utf16le;
        break;
 
    case _O_U16TEXT:
    case _O_U16TEXT | _O_TEXT:
        text_mode = __crt_lowio_text_mode::utf16le;
        break;
 
    case _O_U8TEXT:
    case _O_U8TEXT | _O_TEXT:
        text_mode = __crt_lowio_text_mode::utf8;
        break;
    }
 
 
    // If the file hasn't been opened with the UNICODE flags then we have
    // nothing to do:  the text mode is the default mode that we just set:
    if ((oflag & (_O_WTEXT | _O_U16TEXT | _O_U8TEXT)) == 0)
        return 0;
 
    // If this file refers to a device, we cannot check the BOM, so we have
    // nothing to do:  the text mode is the default mode that we just set:
    if ((options.crt_flags & FDEV) != 0)
        return 0;
 
 
    // Determine whether we need to check or write the BOM, by testing the
    // access with which the file was opened and whether the file already
    // existed or was just created:
    int check_bom = 0;
    int write_bom = 0;
    switch (options.access & GENERIC_READ_WRITE)
    {
    case GENERIC_READ:
        check_bom = 1;
        break;
 
    case GENERIC_WRITE:
    case GENERIC_READ_WRITE:
        switch (options.create)
        {
        // If this file was opened, we will read the BOM if the file was opened
        // with read/write access.  We will write the BOM if and only if the
        // file is empty:
        case OPEN_EXISTING:
        case OPEN_ALWAYS:
        {
            if (_lseeki64_nolock(fh, 0, SEEK_END) != 0)
            {
                if (_lseeki64_nolock(fh, 0, SEEK_SET) == -1)
                    return errno;
 
                // If we have read access, then we need to check the BOM.  Note
                // that we've taken a shortcut here:  if the file is empty, then
                // we do not set this flag because the file doesn't have a BOM
                // to be read.
                check_bom = (options.access & GENERIC_READ) != 0;
            }
            else
            {
                write_bom = 1;
                break;
            }
            break;
        }
 
        // If this is a new or truncated file, then we always write the BOM:
        case CREATE_NEW:
        case CREATE_ALWAYS:
        case TRUNCATE_EXISTING:
        {
            write_bom = 1;
            break;
        }
        }
        break;
    }
 
    if (check_bom)
    {
        int bom = 0;
        int const count = _read_nolock(fh, &bom, UTF8_BOMLEN);
 
        // Intrernal validation:  This branch should never be taken if write_bom
        // is true and count > 0:
        if (count > 0 && write_bom == 1)
        {
            _ASSERTE(0 && "Internal Error");
            write_bom = 0;
        }
 
        switch (count)
        {
        case -1:
            return errno;
 
        case UTF8_BOMLEN:
            if (bom == UTF8_BOM)
            {
                text_mode = __crt_lowio_text_mode::utf8;
                break;
            }
 
        case UTF16_BOMLEN:
            if((bom & BOM_MASK) == UTF16BE_BOM)
            {
                _ASSERTE(0 && "Only UTF-16 little endian & UTF-8 is supported for reads");
                errno = EINVAL;
                return errno;
            }
 
            if((bom & BOM_MASK) == UTF16LE_BOM)
            {
                // We have read three bytes, so we should seek back one byte:
                if(_lseeki64_nolock(fh, UTF16_BOMLEN, SEEK_SET) == -1)
                    return errno;
 
                text_mode = __crt_lowio_text_mode::utf16le;
                break;
            }
 
            // Fall through to default case to lseek to beginning of file
 
        default:
            // The file has no BOM, so we seek back to the beginning:
            if (_lseeki64_nolock(fh, 0, SEEK_SET) == -1)
                return errno;
 
            break;
        }
    }
 
    if (write_bom)
    {
        // If we are creating a new file, we write a UTF-16LE or UTF8 BOM:
        int bom_length = 0;
        int bom = 0;
        switch (text_mode)
        {
        case __crt_lowio_text_mode::utf16le:
        {
            bom        = UTF16LE_BOM;
            bom_length = UTF16_BOMLEN;
            break;
        }
        case __crt_lowio_text_mode::utf8:
        {
            bom        = UTF8_BOM;
            bom_length = UTF8_BOMLEN;
            break;
        }
        }
 
        for (int total_written = 0; bom_length > total_written; )
        {
            char const* const bom_begin = reinterpret_cast<char const*>(&bom);
 
            // Note that the call to write may write less than bom_length
            // characters but not really fail.  We retry until the write fails
            // or we have written all of the characters:
            int const written = _write(fh, bom_begin + total_written, bom_length - total_written);
            if (written == -1)
                return errno;
 
            total_written += written;
        }
    }
 
    return 0; // Success!
}

Referenced by _wsopen_nolock().

create_file()

static HANDLE __cdecl create_file ( PCWSTR const  path, SECURITY_ATTRIBUTES *const  security_attributes, file_options const  options  ) throw ( )

static

Definition at line 222 of file open.cpp.

{
    return CreateFileW(
        path,
        options.access,
        options.share,
        security_attributes,
        options.create,
        options.flags | options.attributes,
        nullptr);
}

decode_access_flags()

static DWORD decode_access_flags ( int const  oflag ) throw ( )

static

Definition at line 240 of file open.cpp.

{
    switch (oflag & (_O_RDONLY | _O_WRONLY | _O_RDWR))
    {
    case _O_RDONLY:
            return GENERIC_READ;
 
    case _O_WRONLY:
        // If the file is being opened in append mode, we give read access as
        // well because in append (a, not a+) mode, we need to read the BOM to
        // determine the encoding (ANSI, UTF-8, or UTF-16).
        if ((oflag & _O_APPEND) && (oflag & (_O_WTEXT | _O_U16TEXT | _O_U8TEXT)) != 0)
            return GENERIC_READ | GENERIC_WRITE;
 
        return GENERIC_WRITE;
 
    case _O_RDWR:
        return GENERIC_READ | GENERIC_WRITE;
    }
 
    // This is unreachable, but the compiler can't tell.
    _VALIDATE_RETURN(("Invalid open flag", 0), EINVAL, static_cast<DWORD>(-1));
    return 0;
}

Referenced by decode_options().

decode_open_create_flags()

static DWORD decode_open_create_flags ( int const  oflag ) throw ( )

static

Definition at line 265 of file open.cpp.

{
    switch (oflag & (_O_CREAT | _O_EXCL | _O_TRUNC))
    {
    case 0:
    case _O_EXCL: // ignore EXCL w/o CREAT
        return OPEN_EXISTING;
 
    case _O_CREAT:
        return OPEN_ALWAYS;
 
    case _O_CREAT | _O_EXCL:
    case _O_CREAT | _O_TRUNC | _O_EXCL:
        return CREATE_NEW;
 
    case _O_TRUNC:
    case _O_TRUNC | _O_EXCL: // ignore EXCL w/o CREAT
        return TRUNCATE_EXISTING;
 
    case _O_CREAT | _O_TRUNC:
        return CREATE_ALWAYS;
    }
 
    // This is unreachable, but the compiler can't tell.
    _VALIDATE_RETURN(("Invalid open flag", 0), EINVAL, static_cast<DWORD>(-1));
    return 0;
}

Referenced by decode_options().

decode_options()

static file_options decode_options ( int const  oflag, int const  shflag, int const  pmode  ) throw ( )

static

Definition at line 337 of file open.cpp.

{
    file_options result;
    result.crt_flags  = 0;
    result.access     = decode_access_flags(oflag);
    result.create     = decode_open_create_flags(oflag);
    result.share      = decode_sharing_flags(shflag, result.access);
    result.attributes = FILE_ATTRIBUTE_NORMAL;
    result.flags      = 0;
 
    if (oflag & _O_NOINHERIT)
    {
        result.crt_flags |= FNOINHERIT;
    }
 
    if (is_text_mode(oflag))
    {
        result.crt_flags |= FTEXT;
    }
 
    if (oflag & _O_CREAT)
    {
        if (((pmode & ~_umaskval) & _S_IWRITE) == 0)
            result.attributes = FILE_ATTRIBUTE_READONLY;
    }
 
    if (oflag & _O_TEMPORARY)
    {
        result.flags  |= FILE_FLAG_DELETE_ON_CLOSE;
        result.access |= DELETE;
        result.share  |= FILE_SHARE_DELETE;
    }
 
    if (oflag & _O_SHORT_LIVED)
    {
        result.attributes |= FILE_ATTRIBUTE_TEMPORARY;
    }
 
    if (oflag & _O_OBTAIN_DIR)
    {
        result.flags |= FILE_FLAG_BACKUP_SEMANTICS;
    }
 
    if (oflag & _O_SEQUENTIAL)
    {
        result.flags |= FILE_FLAG_SEQUENTIAL_SCAN;
    }
    else if (oflag & _O_RANDOM)
    {
        result.flags |= FILE_FLAG_RANDOM_ACCESS;
    }
 
    return result;
}

Referenced by _wsopen_nolock().

decode_sharing_flags()

static DWORD decode_sharing_flags ( int const  shflag, int const  access  ) throw ( )

static

Definition at line 293 of file open.cpp.

{
    switch (shflag)
    {
    case _SH_DENYRW:
        return 0;
 
    case _SH_DENYWR:
        return FILE_SHARE_READ;
 
    case _SH_DENYRD:
        return FILE_SHARE_WRITE;
 
    case _SH_DENYNO:
        return FILE_SHARE_READ | FILE_SHARE_WRITE;
 
    case _SH_SECURE:
        if (access == GENERIC_READ)
            return FILE_SHARE_READ;
        else
            return 0;
    }
 
    _VALIDATE_RETURN(("Invalid sharing flag", 0), EINVAL, static_cast<DWORD>(-1));
    return 0;
}

Referenced by decode_options().

is_text_mode()

static bool is_text_mode ( int const  oflag ) throw ( )

static

Definition at line 320 of file open.cpp.

{
    if (oflag & _O_BINARY)
        return false;
 
    if (oflag & (_O_TEXT | _O_WTEXT | _O_U16TEXT | _O_U8TEXT))
        return true;
 
    // Finally, check the global default mode:
    int fmode;
    _ERRCHECK(_get_fmode(&fmode));
    if (fmode != _O_BINARY)
        return true;
 
    return false;
}

Referenced by decode_options().

truncate_ctrl_z_if_present()

static errno_t truncate_ctrl_z_if_present ( int const  fh ) throw ( )

static

Definition at line 398 of file open.cpp.

{
    // No truncation is possible for devices and pipes:
    if (_osfile(fh) & (FDEV | FPIPE))
        return 0;
 
    // No truncation is necessary for binary files:
    if ((_osfile(fh) & FTEXT) == 0)
        return 0;
 
    // Find the end of the file:
    __int64 const last_char_position = _lseeki64_nolock(fh, -1, SEEK_END);
 
    // If the seek failed, either the file is empty or an error occurred.
    // (It's not an error if the file is empty.)
    if (last_char_position == -1)
    {
        if (_doserrno == ERROR_NEGATIVE_SEEK)
            return 0;
 
        return errno;
    }
 
    // Read the last character.  If the read succeeds and the character
    // is a Ctrl+Z, remove the character from the file by shortening:
    wchar_t c = 0;
    if (_read_nolock(fh, &c, 1) == 0 && c == 26)
    {
        if (_chsize_nolock(fh, last_char_position) == -1)
            return errno;
    }
 
    // Now, rewind the file pointer back to the beginning:
    if (_lseeki64_nolock(fh, 0, SEEK_SET) == -1)
        return errno;
 
    return 0;
}

Referenced by _wsopen_nolock().