Under some specific circumstances, poll(2) would return a positive
integer, but do_exit might had been previously set. This caused libweb
to ignore SIGTERM, with the potential risk for an endless loop.
Some applications might set up a struct handler object to listen on any
port i.e., 0, but still need a way to determine which port number was
eventually selected by the implementation.
Therefore, handler_listen has been reduced to the server initialization
bit, whereas the main loop has been split into its own function, namely
handler_loop.
Because of these changes, it no longer made sense for libweb to write
the selected port to standard output, as this is something now
applications can do on their own.
It was found out there was another project of the same name around
(https://git.sr.ht/~strahinja/slweb/), also related to website
generation.
In order to avoid confusion, a new name has been chosen for this
project. Surprisingly, libweb was not in use by any distributions
(according to https://repology.org and AUR index), and it should
reflect well the intention behind this project i.e., being a library
to build web-related stuff.
Since slweb is meant as a library, it is advisable to keep public header
files under their own directory in order to avoid name clashing i.e.,
#include "something.h"
Now becomes:
#include "slweb/something.h"
server.c kept an array of all of its active clients, calling realloc(3)
everytime its size had to be modified. However, reallocating this array
had the undesired consequence of moving other active clients to other
memory locations.
Potentially, this would result in dangling pointers from other
components that also kept pointers to struct server_client instances
e.g.: handler.c.
For this reason, the array-based approach has been completely dropped,
in favour of a doubly-linked list.
Under some circumstances, clients could cause SIGPIPE to slcl. Since
this signal was not handled by server.c (i.e., via sigaction(3)), slcl
would crash without any error messages printed to stderr.
In such situation, SIGPIPE should not be usually considered a fatal
error, so it is preferrable to close the connection and keep working.
select(2) has a number of well-known issues (e.g.: FD_SETSIZE limiting
the maximum amount of file descriptors to watch) that are mostly solved
by poll(2) and thus can be used as a drop-in replacement.
According to C99 §7.20.3.4:
If memory for the new object cannot be allocated, the old object is not
deallocated and its value is unchanged.
Therefore, a temporary pointer must be used to ensure the original
object can still be deallocated should realloc(3) return a null pointer.
