Re: msvcrt: set mode bits in _fstati64

[Dmitry Timoshkov]

"Juan Lang"  wrote:
> - buf->st_mode = S_IFREG;
> - if (!(hfi.dwFileAttributes & (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM)))
> - {
> - buf->st_mode |= S_IREAD;
> - if (!(hfi.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
> -
>  buf->st_mode |= S_IWRITE;
> - }

Why do you take into account (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM)
at all? They have nothing to do with an ability to read/write files. What
you probably need to consider is a type of a file passed in.

msvcrt: set mode bits in _fstati64

[Juan Lang]

--- Dmitry Timoshkov  wrote:
> Why do you take into account (FILE_ATTRIBUTE_HIDDEN |
> FILE_ATTRIBUTE_SYSTEM)
> at all? They have nothing to do with an ability to read/write files.

You're right.  I didn't do any tests, it was just my poor memory.
> What you probably need to consider is a type of a file passed in.

Hm?  Not sure what you mean here.
--Juan

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msvcrt: set mode bits in _fstati64

[Dmitry Timoshkov]

"Juan Lang"  wrote:
> > What you probably need to consider is a type of a file passed in.
>
> Hm?  Not sure what you mean here.

Apparently a returned info should be based on whether a file handle
resembles an ordinary disk based file, or pipe, or device, or something
else. But that's a target for a separate patch.

msvcrt: set mode bits in _fstati64

[Juan Lang]

--- Dmitry Timoshkov  wrote:
> Apparently a returned info should be based on whether a file handle
> resembles an ordinary disk based file, or pipe, or device, or something
> else. But that's a target for a separate patch.

Got it.  How's this?
--Juan

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msvcrt: set mode bits in _fstati64

[Dmitry Timoshkov]

"Juan Lang"  wrote:
> Got it.  How's this?
> - dw = GetFileType(hand);
> - buf->st_mode = S_IREAD;
> - if (!(hfi.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
> - buf->st_mode |= S_IWRITE;
> - if (hfi.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
> - buf->st_mode |= S_IFDIR;
> - else if (dw == FILE_TYPE_CHAR)
> - buf->st_mode |= S_IFCHR;
> - else
> - buf->st_mode |= S_IFREG;
> - TRACE(":dwFileAttributes = 0x%lx, mode set to 0x%x\n",hfi.dwFileAttributes,
> - buf->st_mode);

Looks better, except that according to MSDN "_S_IFREG bit is set if path specifies
an ordinary file or a device", so you need to add a check for FILE_TYPE_DISK. And
FILE_TYPE_PIPE perhaps should have _S_IFIFO set. Not sure if it's worth to write
a test case for it.

msvcrt: set mode bits in _fstati64

[Juan Lang]

--- Dmitry Timoshkov  wrote:
> Looks better, except that according to MSDN "_S_IFREG bit is set if path
> specifies
> an ordinary file or a device", so you need to add a check for
> FILE_TYPE_DISK.

Interestingly, you can't _open the root directory of a drive in Windows;
it fails with ENOENT.  You also can't _open a directory; it fails with
ENOACCES.  The _S_IFDIR flag never appears to be set, even if you get a
handle to a directory.

The attached test program shows the following output under WinXP:
file c: flags: couldn't open, errno is 14
file c:\ flags: couldn't open, errno is 2
file c:\boot.ini flags: _S_IFREG
file c:\windows flags: couldn't open, errno is 13
directory c: flags: _S_IFREG
directory c:\ flags: _S_IFREG
directory c:\windows flags: _S_IFREG
read pipe flags: _S_IFIFO
write pipe flags: _S_IFIFO

I wasn't really interested in getting this 100% correct; the st_mode set
before was always 0, so it can't be that critical.  Mostly I was tired of
fixme's when running MinGW's gcc.exe under wine.  So, I'll resubmit a
modified patch that isn't entirely correct but is a little closer, anyway
:)

--Juan

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#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/stat.h>
#include <windows.h>

static int firstFlag = 1;

static printFlag(const char *flag)
{
    if (!firstFlag)
        printf("| ");
    printf(flag);
    firstFlag = 0;
}

static void getFDMode(int fd)
{
    struct _stat st;

firstFlag = 1;
    if (_fstat(fd, &st) == 0)
    {
        if (st.st_mode & _S_IFCHR)
            printFlag("_S_IFCHR");
        if (st.st_mode & _S_IFREG)
            printFlag("_S_IFREG");
        if (st.st_mode & _S_IFDIR)
            printFlag("_S_IFDIR");
        if (st.st_mode & _S_IFIFO)
            printFlag("_S_IFIFO");
    }
    putchar('\n');
}

static void getFileMode(const char *file)
{
    int fd = _open(file, _O_RDWR, _S_IREAD | _S_IWRITE);

printf("file %s flags: ", file);
    if (fd == -1)
        fd = _open(file, _O_RDONLY, _S_IREAD);
    if (fd != -1)
    {
        getFDMode(fd);
        _close(fd);
    }
    else
        printf("couldn't open, errno is %d\n", errno);
}

static void getPipeMode(void)
{
    int fds[2];

if (_pipe(fds, 256, O_BINARY) == 0)
    {
        printf("read pipe flags: ");
        getFDMode(fds[0]);
        printf("write pipe flags: ");
        getFDMode(fds[1]);
        _close(fds[0]);
        _close(fds[1]);
    }
}

static void getDirectoryMode(const char *directory)
{
    HANDLE h = CreateFileA(directory, GENERIC_READ, FILE_SHARE_READ, NULL,
     OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);

printf("directory %s flags: ", directory);
    if (h != INVALID_HANDLE_VALUE)
    {
        int fd = _open_osfhandle((intptr_t)h, _O_RDONLY);

if (fd != -1)
        {
            getFDMode(fd);
            _close(fd);
        }
        CloseHandle(h);
    }
    else
        printf("failed with GetLastError() = %ld\n", GetLastError());
}

int main(void)
{
    /* expect errno is 13 (EACCES), can't open a device */
    getFileMode("c:");
    /* expect errno is 2 (ENOENT), can't open a drive */
    getFileMode("c:\");
    getFileMode("c:\boot.ini");
    /* expect errno is 13 (EACCES), can't open a directory */
    getFileMode("c:\windows");
    getDirectoryMode("c:");
    getDirectoryMode("c:\");
    getDirectoryMode("c:\windows");
    getPipeMode();
}