Category: Uncategorized

Microsoft has just open-sourced it’s Windows Subsystem for Linux (WSL).

https://blogs.windows.com/windowsdeveloper/2025/05/19/the-windows-subsystem-for-linux-is-now-open-source/

This is major. WSL runs the FOSS Unix knock-off on their closed source and expensive operating system, making it possible to host Unix applications on it. Cynics might think this was a ploy to still sell a Windows server license instead of people running Linux direct on the hardware. Or you could say it allows lower skilled Windows administrators who couldn’t cope with a command line to still access Linux applications.

Since it first appeared, people have been questioning Microsoft’s open source credentials, as WSL was closed source. Not now. You can get at the source code, customise it and run your own version.

This is great news, but as with anything Microsoft, it’s probably another cyber security attack vector for Windows.

I’ve seen all sorts of stuff on forums about how to process command line argument in C or C++. What a load of fuss and bother. There’s a standard getopt() function in the ‘C’ library, similar to the shell programming command, but it’s not great.

The main problem with getopt() is that it produces its own error message. Although this saves you the trouble, it can be a bit user unfriendly for the user, especially when things get complex. For example, you might have mutually exclusive arguments and want to print out a suitable message. That said, it’ll work most of the time.

Here’s a page showing a good explanation for the GCC version, whcih is pretty standard.

Example of Getopt (The GNU C Library)

But rolling your own is not hard. Here’s a skeleton I use. It’s pretty self-explanatory. My rules allow single options (e.g. -a -b) or combined options (e.g. -ab), or any mixture. “–” ends options, meaning subsequent arguments are going to be a actual arguments.

If you want to pass something as an option, such as a filename, you can. -fmyfile or -f myfile are both handled in the example.

You can add code to detect a long option by adding “if (!strcmp(p,”longname”)) … just after the char c. But I don’t like long options.

#include <stdio.h>

void process(char *s)
{
    printf("Processing %s\n",s);
}

int main (int cnt, char **a)
{
    int i;
    for (i=1; i<cnt && a[i][0] == '-'; i++)
    {
        char *p = &a[i][1];
        char c;
        if (*p == '-')
        {
            i++;
            break;
        }
        while (c = *p)
            switch (*p++)
            {
            case 'a':
                printf("Option a\n");
                break;
                
            case 'b':
                printf("Option b\n");
                break;

            case 'f':
                if (!*p && i+1 < cnt)
                    printf("Value for f=%s\n", a[++i]);
                else
                {
                    printf("Value for f=%s\n", p);
                    while (*p)
                        p++;
                }
                break;
                
            default:
                printf("Bad switch %c\n",c);

            }
    }
    for (;i<cnt;i++)
        process(a[i]);
}

The above code assumes that options precede arguments. If you want to mix them the following code allows for complete anarchy – but you can end it using the “–” option, which will take any following flags as arguments. As a bonus it shows how to add a long argument.

#include <stdio.h>
#include <string.h>

void process(char *s)
{
    printf("Processing %s\n",s);
}

int main (int cnt, char **a)
{
    int i;
    int moreargs=1;

    for (i=1; i<cnt; i++)
    {
            if (moreargs && a[i][0] == '-')
            {
            char *p = &a[i][1];
            char c;
                if (*p == '-')
                {
                    moreargs = 0;
                    continue;
                }
                if (!strcmp(p,"long"))
                {
                    printf("Long argument\n");
                    i++;
                    continue;
                }

                while (c = *p)
                    switch (*p++)
                    {
                    case 'a':
                        printf("Option a\n");
                        break;

                    case 'b':
                        printf("Option b\n");
                        break;

                    case 'f':
                        if (!*p && i+1 < cnt)
                            printf("Value for f=%s\n", a[++i]);
                        else
                        {
                            printf("Value for f=%s\n", p);
                            while (*p)
                                p++;
                        }
                        break;

                        default:
                            printf("Bad switch %c\n",c);

            }
        }
    else
        process(a[i]);
    }
}

Hardly a week goes by without someone contacting me about a problem with their email. Pretty much every time they’re just doing something wrong.

“Your message bounced back because you spelled your friends name wrong.”

I’ve learned to say it without sounding judgemental; or I think I have. Everyone’s done it, after all. It’d be nice if people checked before blaming the mail server, but so would world peace and I’m not hopeful I’ll see either.

But last week was a bit different. Someone got a bounce-back after emailing someone@talktalk.net, but the address in the bounce was someone@www.talktalk.co.uk. I know what you’re thinking; same as me. Someone had manage to type their address wrong in their iPad and the replies were to somewhere silly. (Why’s it always Apple users)

Not so this time. After more complaints I checked TalkTalk’s email server. First thing to check is the MX records. Hang on, there aren’t any!

An domain MX record simply tells other mail servers where to send email for that domain. In the absence of an MX record, a mail server is supposed to send email for a domain to it’s IP address (A record). Not everyone knows. this. As a final roll of the dice, it’s allowed to send it to a domain name’s alias (CNAME).

It turns out that talktalk.net lacks an a record, and it’s CNAME is www.talktalk.co.uk. This kinda makes sense – anyone going to the obsolete talktalk.net web site will end up at www.talktalk.co.uk. Great for web users, but it also means that all the email going to talktalk.net customers will be directed to their mail server. Not cool. Unsurprisingly their web server didn’t know what to make of it.

Was this something weird with my DNS? Nope. I tried it multiple DNS servers on several networks, and Google’s 8.8.8.8 service with exactly the same results. Definitely wrong; and it was a Saturday so there was no one at the company to TalkTalk to. I sent an email to the address their tech support suggested, and got a snotty “we’re not talking to you because you’re not a customer” response. Er, no. At this stage it was on behalf on an ISP trying to resolve a serious problem for their customers. How dumb can you get?

Now TalkTalk is an interesting company. It’s basically a mishmash of many ISPs purchased over time by Charles Dunstone’s Carphone Warehouse. These include Opal, Pipex, Nildram, and OneTel, AOL, Virgin’s ADSL business. The group has not been without its problems, including being slammed by the ASA and Ofcom for not delivering what it promised, and let’s not forget the famous 2015 data heist, malware infected home routers, slamming, and customer privacy concerns (Phorm, URL harvesting with Huawei and so on).

However, a big worry is how these disparate ISPs have been on-boarded to the TalkTalk communication bemouth. The answer is probably “badly”, and woe betide anyone on a legacy service such as an @talktalk.net email address. We had the same problem a year or so ago with @onetel.co.uk emails; TalkTalk had kindly left the service running but had no way of known which customers had left and who was using it for free. It was twenty years before they decided to pull the plug on it and see who squealed.

Naturally I phone around about the talktalk.net MX records to see what other were experiencing, and the consensus was that they’d decide to pull the plug on these legacy accounts too.

Of course, having bad/no MX records in your DNS doesn’t cause an overnight meltdown. DNS entries are often cached, and drop off senders’ servers over time. To add to the confusion, many high volume providers trying to save a few quid don’t even bother to check MX records when sending – they simply use the last known good destination server and “do something” when it fails to connect for a period. Freemail users may not have noticed a problem corresponding with their chums on TalkTalk.net – at least not for a while.

So what did I do? The user was convinced they were infected with malware (as they do) so for a quiet life I faked up the last known good talktalk.net zone in a local DNS server and sat back waiting for the actual server to be turned off. But a week later they’d fixed it; so that’s alright then. For now. I guess legacy customers of the worst domestic broadband provider in the UK (consistently, along with Virgin Media and Plusnet and Vodafone, according to Which? Surveys and Ofcom rankings for customer service) aren’t going to heed any warnings about shifting their email service elsewhere before it’s too late.

Well known conspiracy theorist and tennis player Novak Djokovic appears to have gained entry to Australia without the covid-19 vaccination that he and his wife Jelena oppose, even though it’s a requirement for everyone else.

Jelena Djokovic is on record as believing that 5G mobile phones are the real cause of Covid-19.

It appears Djokovic obtained this exception on a technicality – that he’d tested positive for Covid19 in the last six months. Normally exemptions are granted by an independent (and blind) panel to people with documented medical conditions (usually cardiac) that would make vaccination risky. Immunity through past infection makes the matter less urgent. Does Djokovic really have a dicky ticker? You wouldn’t think so to look at him.

Now the Australian Prime Minister, Scott Morrison, has said he could be on the next plane home because of another technicality – his visa was completed incorrectly.

You’ve got to admire the Australian way of doing things. However, I’d be surprised if the wealth of the rich and famous doesn’t prevail. But whilst I have no interest in watching tennis, I must say this is the shaping up to be the best soap opera coming out of the country since neighbours.

Meanwhile, in France, their controversial but entertaining president has made it clear his strategy is to “piss off” the vaccine dodgers, rather than forcing them to be vaccinated by law.

« Moi, je ne suis pas pour emmerder les Français », confie-t-il tout d’abord. Mais « je peste toute la journée contre l’administration quand elle les bloque. Eh bien, là, les non-vaccinés, j’ai très envie de les emmerder. Et donc, on va continuer de le faire, jusqu’au bout. C’est ça, la stratégie ». Source: Le Parisien

To put this in to context, the UK has been playing softly with the anti-vaxxers, but other European countries are gearing up for compulsory vaccination – starting with Austria, with Italy and Germany not far behind.

Has Macron gone mad? Politicians on the left and right have condemned his language, and the admission of his strategy. However, with 90% of France vaccinated, I suspect he’s gambling that the majority have lost patience with the needle-phobic 10% playing Jacques, and he’s basically asking people to side with him or them. Media politicians have been tricked into knee-jerk siding siding with “them”.

You’d have thought that a google search for “manually add plugin to WordPress” would turn up lots of articles on how to do this, but, er, no. They all seem to tell you to log in to the site and do this or that on the GUI. That’s not doing it manually – it’s using the GUI. If the GUI doesn’t work, then you need to do it manually. Here’s how:

The method is actually simple if you remember it. You download the plugin from the site (e.g. https://wordpress.org/plugins/) and you’ll end up with a DOS/Windows .ZIP file. Unpack this any way you wish and you’ll get a directory with some file in it. As a sanity check, one of these files will have the same name as the directory, but ending in .php.

Take this whole directory and copy it to /wp-content/plugins. That’s the directory – not the files in the directory.

That’s it. You’re done. It’ll appear in the plugins dashboard.