Re: kernel32: Reimplement GetLogicalDrives using the mountmgr

[Alexandre Julliard]

Alexandre Goujon <ale.goujon(a)gmail.com> writes:
> Previous approach was patch #88280
> ---
>  dlls/kernel32/volume.c |   18 +++---------------
>  1 file changed, 3 insertions(+), 15 deletions(-)
>
> diff --git a/dlls/kernel32/volume.c b/dlls/kernel32/volume.c
> index 8377e41..57453bb 100644
> --- a/dlls/kernel32/volume.c
> +++ b/dlls/kernel32/volume.c
> @@ -1435,27 +1435,15 @@ DWORD WINAPI QueryDosDeviceA( LPCSTR devname, LPSTR target, DWORD bufsize )
>   */
>  DWORD WINAPI GetLogicalDrives(void)
>  {
> -    const char *config_dir = wine_get_config_dir();
> -    struct stat st;
> -    char *buffer, *dev;
>      DWORD ret = 0;
> +    WCHAR drive;
>      int i;
>
> -    if (!(buffer = HeapAlloc( GetProcessHeap(), 0, strlen(config_dir) + sizeof("/dosdevices/a:") )))
> -    {
> -        SetLastError( ERROR_NOT_ENOUGH_MEMORY );
> -        return 0;
> -    }
> -    strcpy( buffer, config_dir );
> -    strcat( buffer, "/dosdevices/a:" );
> -    dev = buffer + strlen(buffer) - 2;
> -
>      for (i = 0; i < 26; i++)
>      {
> -        *dev = 'a' + i;
> -        if (!stat( buffer, &st )) ret |= (1 << i);
> +        drive = 'A'+i;
> +        if (get_mountmgr_drive_type(&drive) != DRIVE_UNKNOWN) ret |= (1 << i);
>      }

That's very inefficient. There are better way of enumerating drives,
check for instance QueryDosDevice.

-- 
Alexandre Julliard
julliard(a)winehq.org

kernel32: Reimplement GetLogicalDrives using the mountmgr

[GOUJON Alexandre]

On 07/23/2012 03:03 PM, Alexandre Julliard wrote:
> That's very inefficient. There are better way of enumerating drives,
> check for instance QueryDosDevice.
I'm not sure QueryDosDevice is more efficient :
+ with NULL device name, it returns every MS-DOS device which is not 
what we want
+ if we call it with A: B: C: and so on, we still need a loop
+ plus, we have to dynamically increase the buffer size while 
GetLastError is ERROR_INSUFFICIENT_BUFFER

Would creating a new IOCTL_MOUNTMGR_QUERY_ALL_UNIX_DRIVES be (more) 
acceptable ?

kernel32: Reimplement GetLogicalDrives using the mountmgr

[Alexandre Julliard]

GOUJON Alexandre <ale.goujon(a)gmail.com> writes:

> On 07/23/2012 03:03 PM, Alexandre Julliard wrote:
>> That's very inefficient. There are better way of enumerating drives,
>> check for instance QueryDosDevice.
> I'm not sure QueryDosDevice is more efficient :
> + with NULL device name, it returns every MS-DOS device which is not
> what we want

It's pretty much what we want. Check how it does it.

-- 
Alexandre Julliard
julliard(a)winehq.org

kernel32: Reimplement GetLogicalDrives using the mountmgr

[GOUJON Alexandre]

On 07/23/2012 09:15 PM, Alexandre Julliard wrote:
> GOUJON Alexandre <ale.goujon(a)gmail.com> writes:
>
>> On 07/23/2012 03:03 PM, Alexandre Julliard wrote:
>>> That's very inefficient. There are better way of enumerating drives,
>>> check for instance QueryDosDevice.
>> I'm not sure QueryDosDevice is more efficient :
>> + with NULL device name, it returns every MS-DOS device which is not
>> what we want
> It's pretty much what we want. Check how it does it.
>
I may be mis-using it but on my (virtualized) Win7, QueryDosDevice with 
a NULL argument returns 6651 chars.
I truncated the output to the first strings and here's the result :

Z:
Global
D:
ACPI#PNP0C0A#0#{72631e54-78a4-11d0-bcf7-00aa00b7b32a}
PhysicalDrive0
DISPLAY5
Root#MS_L2TPMINIPORT#0000#{cac88484-7515-4c03-82e6-71a87abac361}
VDRVROOT
STORAGE#Volume#{a76e80e3-477f-11e1-b83a-806e6f6e6963}#0000000006500000#{53f5630d-b6bf-11d0-94f2-00a0c91efb8b}
SW#{eeab7790-c514-11d1-b42b-00805fc1270e}#asyncmac#{cac88484-7515-4c03-82e6-71a87abac361}
Root#SYSTEM#0000#{97ebaacb-95bd-11d0-a3ea-00a0c9223196}
DISPLAY1
Root#MS_SSTPMINIPORT#0000#{cac88484-7515-4c03-82e6-71a87abac361}

And note that using NULL, the strings are concatenated.
So getting each string is not very easy.

But if you say, it's the way to go .. will do that.

kernel32: Reimplement GetLogicalDrives using the mountmgr

[Alexandre Julliard]

GOUJON Alexandre <ale.goujon(a)gmail.com> writes:
> I may be mis-using it but on my (virtualized) Win7, QueryDosDevice
> with a NULL argument returns 6651 chars.
> I truncated the output to the first strings and here's the result :
>
> Z:
> Global
> D:
> ACPI#PNP0C0A#0#{72631e54-78a4-11d0-bcf7-00aa00b7b32a}
> PhysicalDrive0
> DISPLAY5
> Root#MS_L2TPMINIPORT#0000#{cac88484-7515-4c03-82e6-71a87abac361}
> VDRVROOT
> STORAGE#Volume#{a76e80e3-477f-11e1-b83a-806e6f6e6963}#0000000006500000#{53f5630d-b6bf-11d0-94f2-00a0c91efb8b}
> SW#{eeab7790-c514-11d1-b42b-00805fc1270e}#asyncmac#{cac88484-7515-4c03-82e6-71a87abac361}
> Root#SYSTEM#0000#{97ebaacb-95bd-11d0-a3ea-00a0c9223196}
> DISPLAY1
> Root#MS_SSTPMINIPORT#0000#{cac88484-7515-4c03-82e6-71a87abac361}
>
> And note that using NULL, the strings are concatenated.
> So getting each string is not very easy.

It's actually very easy, but you don't even need that. Look at how
QueryDosDevice is implemented and think about it some more.

-- 
Alexandre Julliard
julliard(a)winehq.org