[PATCH] Fix parameter passing containing quote/equal to Windows batch command

[Daniel Dai]

Max,
Thanks for your reply.

Yes, the double quote issue can be reproducible from command line, but
not the equal sign.

Let's demonstrate the equal sign issue with a C program:

#include "unistd.h"

int main(int argc, char** argv) {
    execl("a.bat", "a.bat", "a=b");
    return 0;
}

The intention of the program is to pass "a=b" as a single argument.
However, compile and run it under cygwin, I get:
$ cc -o myprog myprog.c
$ ./myprog
a

I run the program with Visual Studio, I get "a=b".

The way Windows/Unix handles parameter containing equal sign is
different. IMHO, Cygwin should be the place to fill this semantic gap.

Thanks,
Daniel



On Mon, Jan 20, 2014 at 4:30 PM, Max Polk <maxpolk@gmail.com> wrote:
> On 1/20/2014 1:02 AM, Daniel Dai wrote:
>>
>> We notice one issue when running a Windows batch command inside
>> cygwin. Here is one example.
>>
>> Simple batch file:
>> a.bat:
>> echo %1
>>
>> Run it under cygwin:
>> ./a.bat a=b
>> a
>>
>> ./a.bat "a=b"
>> a
>>
>> If we pass additional \"
>> ./a.bat "\"a=b\""
>> "\"a
>>
>> There seems no way to pass a=b into bat.
>
>
> This is how batch files work, and likely not a problem with Cygwin:
> http://support.microsoft.com/kb/35938
> Excerpt: "it is not possible to include an equal sign as an argument to a
> batch file"
>
> Be careful to note that cmd.exe and .bat files naturally split a=b into two
> arguments and strip out the equals sign:
>
> (Run from cmd.exe)
> C:\>Argecho.bat a=b
> FIRST a
> SECOND b
> THIRD
>
> I did notice that adding double quotes (in cmd.exe) will make will it arrive
> as one argument, and note that the double quotes are still there:
>
> (Run from cmd.exe)
> C:\>Argecho.bat "a=b"
> FIRST "a=b"
> SECOND
> THIRD
>
> There is a problem getting Cygwin the above test case, however.
>
> The test script was:
> C:\>type Argecho.bat
> @echo off
> echo FIRST %1
> echo SECOND %2
> echo THIRD %3
>
> When run from Cygwin bash, and you force the double quotes by surrounding
> double quotes "a=b" with single quotes '"a=b"', you seem to get too *many*
> quotes in the batch file:
>
> (Run from bash, the batch file behaves correctly as if run from cmd.exe)
> $ Argecho.bat a=b
> FIRST a
> SECOND b
> THIRD
>
> (Run from bash, same as above since bash removes the double quotes prior to
> passing to program):
> $ Argecho.bat "a=b"
> FIRST a
> SECOND b
> THIRD
>
> (Run from bash, this is what is surprising double surrounded with single)
> $ Argecho.bat '"a=b"'
> FIRST "\"a
> SECOND b\""
> THIRD
>
> It seems that only the final test case above doesn't behave as expected.