Re: cgit about-filter in chroot (httpd + slowcgi)

Paul W. Rankin <pwr@bydasein.com> writes:

> On 2021-03-28 18:56, Omar Polo wrote:
>>> Thanks Omar, I like this approach! I'm pretty green to C so this is
>>> what I have (which doesn't work):
>>> #include <unistd.h>
>>> int main(void) {
>>> execl("/bin/lowdown", NULL);
>>> }
>>> There is no HTML render but at least no errors, but cgit expects
>>> the
>>> resulting HTML printed to STDOUT, so I wonder whether this requires a
>>> return?
>> Assuming that the shell script you posted actually works yes, that
>> snippet (with a small tweak[0]) should work. Make sure it's statically
>> linked.
>> For reference, here's how I would do it
>> $ cat <<EOF > my-cgit-filter.c
>> #include <unistd.h>
>> int
>> main(void)
>> {
>> execl("/bin/lowdown", "lowdown", NULL);
>> return 1;
>> }
>> EOF
>> $ cc my-cgit-filter.c -o my-cgit-filter.c -static
>> $ # check that it's actually statically linked
>> $ ldd my-cgit-filter
>> my-cgit-filter:
>> Start End Type Open Ref GrpRef Name
>> 000005196d856000 000005196d87b000 dlib 1 0 0
>> /tmp/my-cgit-filter
>> [0]: if you compile your snippet, clang should warning about a
>> missing
>> sentinel, something along the lines of
>> > warning: not enough variable arguments in 'execl' declaration
>> to fit a
>> > sentinel [-Wsentinel]
>> > execl("/bin/lowdown", NULL);
>> which should suggest the use of
>> > execl("/bin/lowdown", "lowdown", NULL);
>
> Thank you so much Omar! Making the sentinel change solved it :)

Glad it worked, and apologies for not writing the execl call correctly
the first time I mentioned it :)