Processing flags before files in regsvr32

[Hugh McMaster]

After investigating bug 38870 [1], I came up with some possible solutions to this problem.

1. Duplicate argv.
2. Copy the filename argument into a dynamically allocated array.
3. Copy the filename's iteration number (the 'n' of argv[n]) into a dynamically allocated array.
4. Use NULL pointers after processing to determine whether an argument is a flag or a filename.

Of these answers, option four is the lightest and easiest to implement. It is also efficient.
The idea is to assign argv[i] = NULL after we have processed an argument that is a flag.

So, I'm proposing something like this pseudo-code (there is an actual diff below):

for (i = 1; i < argc; i++)
{
    if (is a flag)
    {
        do something;
        argv[i] = NULL;
    }
}
for (i = 1; i < argc; i++)
{
    if (argv[i]) /* only filenames are valid */
        do something;
}

diff --git a/programs/regsvr32/regsvr32.c b/programs/regsvr32/regsvr32.c
index 449124f..ef895e0 100644
--- a/programs/regsvr32/regsvr32.c
+++ b/programs/regsvr32/regsvr32.c
@@ -270,8 +270,13 @@ int wmain(int argc, WCHAR* argv[])
                 output_write(STRING_USAGE);
                 return 1;
             }
+            argv[i] = NULL;
         }
-        else
+    }
+
+    for (i = 1; i < argc; i++)
+    {
+        if (argv[i])
         {
             WCHAR *DllName = argv[i];
             int res = 0;

The proposed changes work correctly, both with a test DLL and also MediaInfo program from the bug.

Any comments and suggestions are welcome.

[1] https://bugs.winehq.org/show_bug.cgi?id=38870

[Stefan Dösinger]

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Hi,

I haven't really looked into the details, but I am curious if your
change works ok if the user passes a Unix path to regsvr32?

Cheers,
Stefan

Am 2015-07-14 um 13:37 schrieb Hugh McMaster:
> After investigating bug 38870 [1], I came up with some possible
> solutions to this problem.
> - Duplicate argv. 2. Copy the filename argument into a dynamically
>
> allocated array. 3. Copy the filename's iteration number (the 'n'
> of argv[n]) into a dynamically allocated array. 4. Use NULL
> pointers after processing to determine whether an argument is a
> flag or a filename.
>
> Of these answers, option four is the lightest and easiest to
> implement. It is also efficient. The idea is to assign argv[i] =
> NULL after we have processed an argument that is a flag.
>
> So, I'm proposing something like this pseudo-code (there is an
> actual diff below):
>
> for (i = 1; i < argc; i++) { if (is a flag) { do something; argv[i]
> = NULL; } } for (i = 1; i < argc; i++) { if (argv[i]) /* only
> filenames are valid */ do something; }
>
> diff --git a/programs/regsvr32/regsvr32.c
> b/programs/regsvr32/regsvr32.c index 449124f..ef895e0 100644 ---
> a/programs/regsvr32/regsvr32.c +++ b/programs/regsvr32/regsvr32.c 
> @@ -270,8 +270,13 @@ int wmain(int argc, WCHAR* argv[]) 
> output_write(STRING_USAGE); return 1; } +            argv[i] =
> NULL; } -        else +    } + +    for (i = 1; i < argc; i++) +
> { +        if (argv[i]) { WCHAR *DllName = argv[i]; int res = 0;
>
> The proposed changes work correctly, both with a test DLL and also
> MediaInfo program from the bug.
>
> Any comments and suggestions are welcome.
>
> [1] https://bugs.winehq.org/show_bug.cgi?id=38870
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[Hugh McMaster]

On Wednesday, 15 July 2015 13:05:15 +0200, Stefan Dösinger wrote:
> I haven't really looked into the details, but I am curious if your
> change works ok if the user passes a Unix path to regsvr32?

Hi Stefan,

Users can still pass Unix paths to regsvr32.

A comparison of regsvr32 functionality in Windows, Wine and with the proposed patch can be found at link [1].

[1] https://www.dropbox.com/s/ezu04poan99bf6t/regsvr32-comparison.pdf?dl=0