Mirrors/fish-shell
2
0
Fork 0
mirror of https://github.com/fish-shell/fish-shell synced 2024-11-14 17:07:44 +00:00
Code Issues Projects Releases Packages Wiki Activity

Optimize __fish_print_hostnames hosts file loading/parsing

Browse source 
Reordering the `getent hosts` and read from `/etc/hosts` combined with
minimizing shelling and job invocations for parsing the output results
in a profiled and benchmarked ~42% decrease in the time it takes to run,
and that's on a machine with a very small hosts list in the first place.

This update also fixes the hadling of IPv6 addresses in the hosts
output, which were previously ignored, and ignores 127.* loopback
addresses in addition to the 0.0.0.0 address (plus adds support for
shorter IPv4 notations).
This commit is contained in:
Mahmoud Al-Qudsi 2019-09-05 20:44:12 -05:00
parent b760fd9064
commit 06317f0a98
1 changed files with 38 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

69
share/functions/__fish_print_hostnames.fish
View file

@ -1,22 +1,26 @@
function __fish_print_hostnames -d "Print a list of known hostnames"
# Print all hosts from /etc/hosts. Use 'getent hosts' on OSes that support it
# (apparently just Cygwin does not).
#
# Test if 'getent hosts' works and redirect output so errors don't print.
#
# This is all done under the assumption that `getent` *might* print more hosts than the static /etc/hosts.
type -q getent
# Ignore zero IPs.
and getent hosts 2>/dev/null | string match -r -v '^0.0.0.0' | string replace -r '^\s*\S+\s+' '' | string split ' '
# We care about _getent_s status, not `string split`s.
if test $pipestatus[1] -ne 0; and test -r /etc/hosts
# Ignore commented lines and functionally empty lines.
string match -r -v '^\s*0.0.0.0|^\s*#|^\s*$' </etc/hosts | string replace -r -a '#.*$' '' | string replace -r '^\s*\S+\s+' '' | string trim | string replace -r -a '\s+' ' ' | string split ' '
end
# This function used to primarily query `getent hosts` and only read from `/etc/hosts` if
# `getent` did not exist or `getent hosts` failed, based off the (documented) assumption that
# the former *might* return more hosts than the latter, which has never been officially noted
# to be the case. As `getent` is several times slower, involves shelling out, and is not
# available on some platforms (Cygin and at least some versions of macOS, such as 10.10), that
# order is now reversed and `getent hosts` is only used if the hosts file is not found at
# `/etc/hosts` for portability reasons.
begin
test -r /etc/hosts && read -z </etc/hosts
or type -q getent && getent hosts 2>/dev/null
end |
# Ignore comments, own IP addresses (127.*, 0.0[.0[.0]], ::1), non-host IPs (fe00::*, ff00::*),
# and leading/trailing whitespace. Split results on whitespace to handle multiple aliases for
# one IP.
string replace -irf '^\s*?(?!(?:#|0\.|127\.|ff0|fe0|::1))\S+\s*(.*?)\s*$' '$1' |
string split ' '
# Print nfs servers from /etc/fstab
if test -r /etc/fstab
string match -r '^\s*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3]:|^[a-zA-Z\.]*:' </etc/fstab | string replace -r ':.*' ''
string match -r '^\s*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3]:|^[a-zA-Z\.]*:' </etc/fstab |
string replace -r ':.*' ''
end
# Check hosts known to ssh.
@ -25,25 +29,28 @@ function __fish_print_hostnames -d "Print a list of known hostnames"
# The directory is available as $PREFIX/etc, but that variable name is so generic that
# it would cause false-positives.
# Also, some people might use /usr/local/etc.
set -l known_hosts ~/.ssh/known_hosts{,2} {/data/data/com.termux/files/usr,/usr/local,}/etc/ssh/{,ssh_}known_hosts{,2}
set -l known_hosts ~/.ssh/known_hosts{,2} \
{/data/data/com.termux/files/usr,/usr/local,}/etc/ssh/{,ssh_}known_hosts{,2}
# Check default ssh configs.
set -l ssh_config
# Get alias and commandline options.
set -l ssh_func_tokens (functions ssh | string match '*command ssh *' | string split ' ')
set -l ssh_command $ssh_func_tokens (commandline -cpo)
# Extract ssh config path from last -F short option.
if contains -- '-F' $ssh_command
set -l ssh_config_path_is_next 1
for token in $ssh_command
if contains -- '-F' $token
set ssh_config_path_is_next 0
else if test $ssh_config_path_is_next -eq 0
set ssh_config (eval "echo $token")
set ssh_config_path_is_next 1
set -l ssh_config ~/.ssh/config
# Inherit settings and parameters from `ssh` aliases, if any
if functions -q ssh
# Get alias and commandline options.
set -l ssh_func_tokens (functions ssh | string match '*command ssh *' | string split ' ')
set -l ssh_command $ssh_func_tokens (commandline -cpo)
# Extract ssh config path from last -F short option.
if contains -- '-F' $ssh_command
set -l ssh_config_path_is_next 1
for token in $ssh_command
if contains -- '-F' $token
set ssh_config_path_is_next 0
else if test $ssh_config_path_is_next -eq 0
set ssh_config (eval "echo $token")
set ssh_config_path_is_next 1
end
end
end
else
set ssh_config $ssh_config ~/.ssh/config
end
# Extract ssh config paths from Include option