Let's encapsulate the code, which checks the applied nofile limit into
a separate helper check_nofile_lim_and_prealloc_fd(). Let's keep in this new
function scope the block, which tries to create a copy of FD with the highest
number, if prealloc-fd is set in the configuration.
In step_init_3() we try to apply provided or calculated earlier haproxy
maxsock and memmax limits.
Let's encapsulate these code blocks in dedicated functions:
apply_nofile_limit() and apply_memory_limit() and let's move them into
limits.c. Limits.c gathers now all the logic for calculating and setting
system limits in dependency of the provided configuration.
Let's encapsulate the code, which calculates global.maxconn and
global.maxsslconn into a dedicated function set_global_maxconn() and let's
move this function in limits.c. In limits.c we keep helpers to calculate and
check haproxy internal limits, based on the system nofile and memory limits.
It is more handy to use LIM2A in debug_parse_cli_show_dev(), as it allows to
show a custom string ("unlimited"), if a given limit value equals to 0.
normalize_rlim() handler is needed to convert properly RLIM_INFINITY to zero,
with the respect of type sizes, as rlim_t is always 4 bytes on 32bit and
64bit arch.
Let's encapsulate the check of all supported for now process internal limits in
a separate function. This will help in cases, when we need to simply check if
we have even only one limit set in the configuration file. It's important, as
the default value for a one limit (fd-hard-limits, for example) sometimes must
not affect the computation of the others.
The code which gets, sets and checks initial and current fd limits and process
related limits (maxconn, maxsock, ulimit-n, fd-hard-limit) is spread around
different functions in haproxy.c and in fd.c. Let's group it together in
dedicated limits.c and limits.h.
This patch is done in order to prepare the moving of limits-related functions
from different places to the new 'limits' compilation unit. It helps to keep
clean the next patch, which will do only the move without any additional
modifications.
Such detailed split is needed in order to be sure not to break accidentally
limits logic and in order to be able to compile each commit separately in case
of git-bisect.
