* [PATCH 08/13] lei: avoid racing on unlink + bind + listen
2021-02-08 9:05 7% [PATCH 00/13] lei approxidate, startup fix, --alert Eric Wong
@ 2021-02-08 9:05 7% ` Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2021-02-08 9:05 UTC (permalink / raw)
To: meta
When multiple lei(1) processes are starting in parallel without
lei-daemon already running, it's possible for them to trample
each others' socket path trying to start lei-daemon. Lock
errors.log before unlink/bind/listen. We'll add an extra
connect(2) attempt to check if the starter lost the race.
Without this change, a stress script like the following could
easily cause problems:
lei q -o ~/tmp/a foo ... &
lei q -o ~/tmp/b bar ... &
lei q -o ~/tmp/c quux ... &
lei q -o ~/tmp/d baz ... &
---
lib/PublicInbox/LEI.pm | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 2f370f52..cddb94e9 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -22,7 +22,7 @@ use PublicInbox::Syscall qw(SFD_NONBLOCK EPOLLIN EPOLLET);
use PublicInbox::Sigfd;
use PublicInbox::DS qw(now dwaitpid);
use PublicInbox::Spawn qw(spawn popen_rd);
-use PublicInbox::OnDestroy;
+use PublicInbox::Lock;
use Time::HiRes qw(stat); # ctime comparisons for config cache
use File::Path qw(mkpath);
use File::Spec;
@@ -828,17 +828,19 @@ sub accept_dispatch { # Listener {post_accept} callback
vec(my $rvec = '', fileno($sock), 1) = 1;
select($rvec, undef, undef, 60) or
return send($sock, 'timed out waiting to recv FDs', MSG_EOR);
- my @fds = $recv_cmd->($sock, my $buf, 4096 * 33); # >MAX_ARG_STRLEN
+ # (4096 * 33) >MAX_ARG_STRLEN
+ my @fds = $recv_cmd->($sock, my $buf, 4096 * 33) or return; # EOF
if (scalar(@fds) == 4) {
for my $i (0..3) {
my $fd = shift(@fds);
open($self->{$i}, '+<&=', $fd) and next;
send($sock, "open(+<&=$fd) (FD=$i): $!", MSG_EOR);
}
- } else {
- my $msg = "recv_cmd failed: $!";
- warn $msg;
+ } elsif (!defined($fds[0])) {
+ warn(my $msg = "recv_cmd failed: $!");
return send($sock, $msg, MSG_EOR);
+ } else {
+ return;
}
$self->{2}->autoflush(1); # keep stdout buffered until x_it|DESTROY
# $ENV_STR = join('', map { "\0$_=$ENV{$_}" } keys %ENV);
@@ -923,9 +925,19 @@ sub dump_and_clear_log {
# lei(1) calls this when it can't connect
sub lazy_start {
my ($path, $errno, $narg) = @_;
- if ($errno == ECONNREFUSED) {
- unlink($path) or die "unlink($path): $!";
- } elsif ($errno != ENOENT) {
+ local ($errors_log, $listener);
+ ($errors_log) = ($path =~ m!\A(.+?/)[^/]+\z!);
+ $errors_log .= 'errors.log';
+ my $addr = pack_sockaddr_un($path);
+ my $lk = bless { lock_path => $errors_log }, 'PublicInbox::Lock';
+ $lk->lock_acquire;
+ socket($listener, AF_UNIX, SOCK_SEQPACKET, 0) or die "socket: $!";
+ if ($errno == ECONNREFUSED || $errno == ENOENT) {
+ return if connect($listener, $addr); # another process won
+ if ($errno == ECONNREFUSED && -S $path) {
+ unlink($path) or die "unlink($path): $!";
+ }
+ } else {
$! = $errno; # allow interpolation to stringify in die
die "connect($path): $!";
}
@@ -935,10 +947,10 @@ sub lazy_start {
BSD::Resource::setrlimit($NOFILE, $h, $h) if $s < $h;
}
umask(077) // die("umask(077): $!");
- local $listener;
- socket($listener, AF_UNIX, SOCK_SEQPACKET, 0) or die "socket: $!";
- bind($listener, pack_sockaddr_un($path)) or die "bind($path): $!";
+ bind($listener, $addr) or die "bind($path): $!";
listen($listener, 1024) or die "listen: $!";
+ $lk->lock_release;
+ undef $lk;
my @st = stat($path) or die "stat($path): $!";
my $dev_ino_expect = pack('dd', $st[0], $st[1]); # dev+ino
local $oldset = PublicInbox::DS::block_signals();
@@ -956,9 +968,6 @@ sub lazy_start {
require PublicInbox::Listener;
require PublicInbox::EOFpipe;
(-p STDOUT) or die "E: stdout must be a pipe\n";
- local $errors_log;
- ($errors_log) = ($path =~ m!\A(.+?/)[^/]+\z!);
- $errors_log .= 'errors.log';
open(STDIN, '+>>', $errors_log) or die "open($errors_log): $!";
STDIN->autoflush(1);
dump_and_clear_log("from previous daemon process:\n");
^ permalink raw reply related [relevance 7%]
* [PATCH 00/13] lei approxidate, startup fix, --alert
@ 2021-02-08 9:05 7% Eric Wong
2021-02-08 9:05 7% ` [PATCH 08/13] lei: avoid racing on unlink + bind + listen Eric Wong
0 siblings, 1 reply; 2+ results
From: Eric Wong @ 2021-02-08 9:05 UTC (permalink / raw)
To: meta
I've redone and squashed some changes into PATCH 1/13 which
was posted yesterday.
3/13 (SIGWINCH) is rebase necessary after 1/13,
4/13 (--alert=CMD) is a generalized take on 3/13.
12/13 is...
Eric Wong (13):
lei q: improve remote mboxrd UX + MUA
lei_xsearch: quiet Eml warnings from remote mboxrds
lei q: SIGWINCH process group with the terminal
lei q: support --alert=CMD for early MUA users
tests: favor IPv6
ds: improve add_timer usability
lei: start_pager: drop COLUMNS default
lei: avoid racing on unlink + bind + listen
lei: drop BSD::Resource usage
git: implement date_parse method
lei q: use git approxidate with d:, dt: and rt: ranges
search: use one git-rev-parse process for all dates
spawnpp: raise exception on E2BIG errors
lib/PublicInbox/DS.pm | 10 ++--
lib/PublicInbox/ExtSearchIdx.pm | 5 +-
lib/PublicInbox/FakeInotify.pm | 4 +-
lib/PublicInbox/Git.pm | 10 +++-
lib/PublicInbox/IPC.pm | 8 +--
lib/PublicInbox/LEI.pm | 100 ++++++++++++++++++++++----------
lib/PublicInbox/LeiCurl.pm | 11 +++-
lib/PublicInbox/LeiMirror.pm | 5 +-
lib/PublicInbox/LeiOverview.pm | 6 +-
lib/PublicInbox/LeiQuery.pm | 12 ++--
lib/PublicInbox/LeiToMail.pm | 24 ++++----
lib/PublicInbox/LeiXSearch.pm | 97 ++++++++++++++++++++-----------
lib/PublicInbox/Search.pm | 86 +++++++++++++++++++++++++++
lib/PublicInbox/SpawnPP.pm | 23 ++++++--
lib/PublicInbox/TestCommon.pm | 30 ++++++++--
lib/PublicInbox/Watch.pm | 19 +++---
script/lei | 16 ++---
t/extsearch.t | 2 +-
t/git.t | 17 +++++-
t/httpd-corner.psgi | 2 +-
t/httpd-corner.t | 12 ++--
t/httpd-https.t | 2 +-
t/httpd-unix.t | 7 +--
t/httpd.t | 8 +--
t/imapd-tls.t | 4 +-
t/imapd.t | 8 +--
t/lei-mirror.t | 2 +-
t/nntpd-tls.t | 4 +-
t/nntpd.t | 11 ++--
t/psgi_attach.t | 2 +-
t/psgi_v2.t | 2 +-
t/search.t | 51 ++++++++++++++++
t/solver_git.t | 2 +-
t/v2mirror.t | 3 +-
t/v2writable.t | 3 +-
t/www_altid.t | 2 +-
t/www_listing.t | 3 +-
xt/git-http-backend.t | 4 +-
xt/httpd-async-stream.t | 2 +-
xt/imapd-mbsync-oimap.t | 4 +-
xt/imapd-validate.t | 4 +-
xt/mem-imapd-tls.t | 2 +-
xt/nntpd-validate.t | 3 +-
xt/perf-nntpd.t | 16 ++---
xt/solver.t | 3 +-
45 files changed, 441 insertions(+), 210 deletions(-)
^ permalink raw reply [relevance 7%]
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2021-02-08 9:05 7% ` [PATCH 08/13] lei: avoid racing on unlink + bind + listen Eric Wong
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