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powerlevel10k/internal/worker.zsh
romkatv 7354eeaa96 workaround for a bug in sysread
There is a bug in sysread from zsh/system. It triggers in the
following case:

1. zsh has been compiled with HAVE_SELECT and without HAVE_POLL.
2. sysread is called with timeout (-t).
3. the input file descriptor is valid but there is no data to read.
4. errno happens to be EINTR prior to the call to sysread.

This results in an infinite loop in sysread:

  while ((ret = select(infd+1, (SELECT_ARG_2_T) &fds,
                       NULL, NULL,&select_tv)) < 1) {
    if (errno != EINTR || errflag || retflag || breaks || contflag)
      break;
  }

Here select() keeps returning 0, indicating timeout. This is not an
error, so errno doesn't get set. If it was EINTR prior to the call,
it stays EINTR, and the loop keeps spinning.

As a workaround, powerlevel10k sets errno to ENOTTY (any value other
than EINTR will do) prior to calling sysread with timeout.
2020-02-05 14:37:43 +01:00

202 lines
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# invoked in worker: _p9k_worker_main <pgid>
function _p9k_worker_main() {
mkfifo $_p9k__worker_file_prefix.fifo || return
echo -nE - s$_p9k_worker_pgid$'\x1e' || return
exec 0<$_p9k__worker_file_prefix.fifo || return
zf_rm $_p9k__worker_file_prefix.fifo || return
local -i reset
local req fd
local -a ready
local _p9k_worker_request_id
local -A _p9k_worker_fds # fd => id$'\x1f'callback
local -A _p9k_worker_inflight # id => inflight count
function _p9k_worker_reply() {
print -nr -- e${(pj:\n:)@}$'\x1e' || kill -- -$_p9k_worker_pgid
}
# usage: _p9k_worker_async <work> <callback>
function _p9k_worker_async() {
local fd async=$1
sysopen -r -o cloexec -u fd <(
() { eval $async; } && print -n '\x1e') || return
(( ++_p9k_worker_inflight[$_p9k_worker_request_id] ))
_p9k_worker_fds[$fd]=$_p9k_worker_request_id$'\x1f'$2
}
trap '' PIPE
{
while zselect -a ready 0 ${(k)_p9k_worker_fds}; do
[[ $ready[1] == -r ]] || return
for fd in ${ready:1}; do
if [[ $fd == 0 ]]; then
local buf=
while true; do
[[ -t 0 ]]
sysread -t 0 'buf[$#buf+1]' && continue
(( $? == 4 )) || return
[[ $buf[-1] == (|$'\x1e') ]] && break
sysread 'buf[$#buf+1]' || return
done
for req in ${(ps:\x1e:)buf}; do
_p9k_worker_request_id=${req%%$'\x1f'*}
() { eval $req[$#_p9k_worker_request_id+2,-1] }
(( $+_p9k_worker_inflight[$_p9k_worker_request_id] )) && continue
print -rn -- d$_p9k_worker_request_id$'\x1e' || return
done
else
local REPLY=
while true; do
sysread -i $fd 'REPLY[$#REPLY+1]' && continue
(( $? == 5 )) || return
break
done
local cb=$_p9k_worker_fds[$fd]
_p9k_worker_request_id=${cb%%$'\x1f'*}
unset "_p9k_worker_fds[$fd]"
exec {fd}>&-
if [[ $REPLY == *$'\x1e' ]]; then
REPLY[-1]=""
() { eval $cb[$#_p9k_worker_request_id+2,-1] }
fi
if (( --_p9k_worker_inflight[$_p9k_worker_request_id] == 0 )); then
unset "_p9k_worker_inflight[$_p9k_worker_request_id]"
print -rn -- d$_p9k_worker_request_id$'\x1e' || return
fi
fi
done
done
} always {
kill -- -$_p9k_worker_pgid
}
}
# invoked in master: _p9k_worker_invoke <request-id> <list>
function _p9k_worker_invoke() {
[[ -n $_p9k__worker_resp_fd ]] || return
local req=$1$'\x1f'$2$'\x1e'
if [[ -n $_p9k__worker_req_fd && $+_p9k__worker_request_map[$1] == 0 ]]; then
_p9k__worker_request_map[$1]=
print -rnu $_p9k__worker_req_fd -- $req
else
_p9k__worker_request_map[$1]=$req
fi
}
function _p9k_worker_cleanup() {
eval "$__p9k_intro"
[[ $_p9k__worker_shell_pid == $sysparams[pid] ]] && _p9k_worker_stop
return 0
}
function _p9k_worker_stop() {
add-zsh-hook -D zshexit _p9k_worker_cleanup
[[ -n $_p9k__worker_resp_fd ]] && zle -F $_p9k__worker_resp_fd
[[ -n $_p9k__worker_resp_fd ]] && exec {_p9k__worker_resp_fd}>&-
[[ -n $_p9k__worker_req_fd ]] && exec {_p9k__worker_req_fd}>&-
[[ -n $_p9k__worker_pid ]] && kill -- -$_p9k__worker_pid 2>/dev/null
[[ -n $_p9k__worker_file_prefix ]] && zf_rm -f $_p9k__worker_file_prefix.fifo
_p9k__worker_pid=
_p9k__worker_req_fd=
_p9k__worker_resp_fd=
_p9k__worker_shell_pid=
_p9k__worker_request_map=()
return 0
}
function _p9k_worker_receive() {
eval "$__p9k_intro"
[[ -z $_p9k__worker_resp_fd ]] && return
{
(( $# <= 1 )) || return
local buf resp
while true; do
[[ -t $_p9k__worker_resp_fd ]]
sysread -t 0 -i $_p9k__worker_resp_fd 'buf[$#buf+1]' && continue
(( $? == 4 )) || return
[[ $buf == (|*$'\x1e')$'\x05'# ]] && break
sysread -i $_p9k__worker_resp_fd 'buf[$#buf+1]' || return
done
local -i reset max_reset
for resp in ${(ps:\x1e:)${buf//$'\x05'}}; do
local arg=$resp[2,-1]
case $resp[1] in
d)
local req=$_p9k__worker_request_map[$arg]
if [[ -n $req ]]; then
_p9k__worker_request_map[$arg]=
print -rnu $_p9k__worker_req_fd -- $req || return
else
unset "_p9k__worker_request_map[$arg]"
fi
;;
e)
() { eval $arg }
(( reset > max_reset )) && max_reset=reset
;;
s)
[[ -z $_p9k__worker_pid ]] || return
[[ $arg == <1-> ]] || return
_p9k__worker_pid=$arg
sysopen -w -o cloexec -u _p9k__worker_req_fd $_p9k__worker_file_prefix.fifo || return
local req=
for req in $_p9k__worker_request_map; do
print -rnu $_p9k__worker_req_fd -- $req || return
done
_p9k__worker_request_map=({${(k)^_p9k__worker_request_map},''})
;;
*)
return 1
;;
esac
done
if (( max_reset == 2 )); then
_p9k_refresh_reason=worker
_p9k_set_prompt
_p9k_refresh_reason=''
fi
(( max_reset )) && _p9k_reset_prompt
return 0
} always {
(( $? )) && _p9k_worker_stop
}
}
function _p9k_worker_start() {
setopt monitor || return
{
[[ -n $_p9k__worker_resp_fd ]] && return
_p9k__worker_file_prefix=${TMPDIR:-/tmp}/p10k.worker.$EUID.$$.$EPOCHSECONDS
sysopen -r -o cloexec -u _p9k__worker_resp_fd <(
if [[ -n $_POWERLEVEL9K_WORKER_LOG_LEVEL ]]; then
exec 2>$_p9k__worker_file_prefix.log
setopt xtrace
else
exec 2>/dev/null
fi
zmodload zsh/zselect || return
! { zselect -t0 || (( $? != 1 )) } || return
local _p9k_worker_pgid=$sysparams[pid]
_p9k_worker_main &
{
trap '' PIPE
while syswrite $'\x05'; do zselect -t 1000; done
zf_rm -f $_p9k__worker_file_prefix.fifo
kill -- -$_p9k_worker_pgid
} &
exec =true) || return
zle -F $_p9k__worker_resp_fd _p9k_worker_receive
_p9k__worker_shell_pid=$sysparams[pid]
add-zsh-hook zshexit _p9k_worker_cleanup
} always {
(( $? )) && _p9k_worker_stop
}
}