From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 10/30] xap_helper: simplify SIGTERM exit checks
Date: Tue, 17 Oct 2023 23:37:55 +0000 [thread overview]
Message-ID: <20231017233815.1637932-11-e@80x24.org> (raw)
In-Reply-To: <20231017233815.1637932-1-e@80x24.org>
We can just close the socket FD to ensure things fail ASAP
when a SIGTERM hits instead of wasting time making getppid(2)
syscalls.
---
lib/PublicInbox/XapHelper.pm | 7 +++----
lib/PublicInbox/xap_helper.h | 28 ++++++++++++++++------------
2 files changed, 19 insertions(+), 16 deletions(-)
diff --git a/lib/PublicInbox/XapHelper.pm b/lib/PublicInbox/XapHelper.pm
index fe8d20f4..c31fe9a2 100644
--- a/lib/PublicInbox/XapHelper.pm
+++ b/lib/PublicInbox/XapHelper.pm
@@ -17,7 +17,7 @@ use autodie qw(open);
use POSIX qw(:signal_h);
use Fcntl qw(LOCK_UN LOCK_EX);
my $X = \%PublicInbox::Search::X;
-our (%SRCH, %WORKERS, $parent_pid, $alive, $nworker, $workerset);
+our (%SRCH, %WORKERS, $alive, $nworker, $workerset);
our $stderr = \*STDERR;
# only short options for portability in C++ implementation
@@ -177,7 +177,8 @@ sub recv_loop {
local $SIG{__WARN__} = sub { print $stderr @_ };
my $rbuf;
my $in = \*STDIN;
- while (!defined($parent_pid) || getppid == $parent_pid) {
+ local $SIG{TERM} = sub { undef $in };
+ while (defined($in)) {
PublicInbox::DS::sig_setmask($workerset);
my @fds = $PublicInbox::IPC::recv_cmd->($in, $rbuf, 4096*33);
scalar(@fds) or exit(66); # EX_NOINPUT
@@ -218,7 +219,6 @@ sub start_worker ($) {
if ($pid == 0) {
undef %WORKERS;
PublicInbox::DS::Reset();
- $SIG{TERM} = sub { $parent_pid = -1 };
$SIG{TTIN} = $SIG{TTOU} = 'IGNORE';
$SIG{CHLD} = 'DEFAULT'; # Xapian may use this
recv_loop();
@@ -267,7 +267,6 @@ sub start (@) {
for (POSIX::SIGTERM, POSIX::SIGCHLD) {
$workerset->delset($_) or die "delset($_): $!";
}
- local $parent_pid = $$;
my $sig = {
TTIN => sub {
if ($alive) {
diff --git a/lib/PublicInbox/xap_helper.h b/lib/PublicInbox/xap_helper.h
index c68202c3..fafb392d 100644
--- a/lib/PublicInbox/xap_helper.h
+++ b/lib/PublicInbox/xap_helper.h
@@ -72,8 +72,8 @@
assert(ckvar______ == (expect) && "BUG" && __FILE__ && __LINE__); \
} while (0)
-static const int sock_fd = STDIN_FILENO; // SOCK_SEQPACKET as stdin :P
-static volatile pid_t parent_pid; // may be set in worker sighandler (sigw)
+// sock_fd is modified in signal handler, yes, it's SOCK_SEQPACKET
+static volatile int sock_fd = STDIN_FILENO;
static sigset_t fullset, workerset;
static bool alive = true;
#if STDERR_ASSIGNABLE
@@ -640,6 +640,7 @@ static bool recv_req(struct req *req, char *rbuf, size_t *len)
union my_cmsg cmsg = {};
struct msghdr msg = {};
struct iovec iov;
+ ssize_t r;
iov.iov_base = rbuf;
iov.iov_len = *len;
msg.msg_iov = &iov;
@@ -650,25 +651,29 @@ static bool recv_req(struct req *req, char *rbuf, size_t *len)
// allow SIGTERM to hit
CHECK(int, 0, sigprocmask(SIG_SETMASK, &workerset, NULL));
- ssize_t r = recvmsg(sock_fd, &msg, 0);
+again:
+ r = recvmsg(sock_fd, &msg, 0);
if (r == 0) {
exit(EX_NOINPUT); /* grandparent went away */
} else if (r < 0) {
- if (errno == EINTR)
- return false; // retry recv_loop
- err(EXIT_FAILURE, "recvmsg");
+ switch (errno) {
+ case EINTR: goto again;
+ case EBADF: if (sock_fd < 0) exit(0);
+ // fall-through
+ default: err(EXIT_FAILURE, "recvmsg");
+ }
}
// success! no signals for the rest of the request/response cycle
CHECK(int, 0, sigprocmask(SIG_SETMASK, &fullset, NULL));
*len = r;
- if (r > 0 && cmsg.hdr.cmsg_level == SOL_SOCKET &&
+ if (cmsg.hdr.cmsg_level == SOL_SOCKET &&
cmsg.hdr.cmsg_type == SCM_RIGHTS) {
- size_t len = cmsg.hdr.cmsg_len;
+ size_t clen = cmsg.hdr.cmsg_len;
int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
size_t i;
- for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= len; i++) {
+ for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= clen; i++) {
int fd = *fdp++;
const char *mode = NULL;
int fl = fcntl(fd, F_GETFL);
@@ -923,7 +928,7 @@ static void stderr_restore(FILE *tmp_err)
static void sigw(int sig) // SIGTERM handler for worker
{
- parent_pid = -1; // break out of recv_loop
+ sock_fd = -1; // break out of recv_loop
}
static void recv_loop(void) // worker process loop
@@ -934,7 +939,7 @@ static void recv_loop(void) // worker process loop
CHECK(int, 0, sigaction(SIGTERM, &sa, NULL));
- while (!parent_pid || getppid() == parent_pid) {
+ while (sock_fd == 0) {
size_t len = sizeof(rbuf);
struct req req = {};
if (!recv_req(&req, rbuf, &len))
@@ -1197,7 +1202,6 @@ int main(int argc, char *argv[])
}
CHECK(int, 0, sigdelset(&workerset, SIGTERM));
CHECK(int, 0, sigdelset(&workerset, SIGCHLD));
- parent_pid = getpid();
nworker_hwm = nworker;
worker_pids = (pid_t *)calloc(nworker, sizeof(pid_t));
if (!worker_pids) err(EXIT_FAILURE, "calloc");
next prev parent reply other threads:[~2023-10-17 23:38 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-17 23:37 [PATCH 00/30] autodie-ification and code simplifications Eric Wong
2023-10-17 23:37 ` [PATCH 01/30] lei_mirror: start converting to autodie Eric Wong
2023-10-17 23:37 ` [PATCH 02/30] lei_mirror: autodie most `close' calls Eric Wong
2023-10-17 23:37 ` [PATCH 03/30] lei_mirror: use autodie for most `open' calls Eric Wong
2023-10-17 23:37 ` [PATCH 04/30] git: introduce read_all function Eric Wong
2023-10-17 23:37 ` [PATCH 05/30] import: use read_all to detect short reads Eric Wong
2023-10-17 23:37 ` [PATCH 06/30] lei_mirror: use read_all Eric Wong
2023-10-17 23:37 ` [PATCH 07/30] use read_all in more places to improve safety Eric Wong
2023-10-17 23:37 ` [PATCH 08/30] xap_helper*: use autodie in more places Eric Wong
2023-10-17 23:37 ` [PATCH 09/30] xap_helper: die more easily in both implementations Eric Wong
2023-10-17 23:37 ` Eric Wong [this message]
2023-10-17 23:37 ` [PATCH 11/30] xap_helper: autodie for getsockopt Eric Wong
2023-10-17 23:37 ` [PATCH 12/30] xap_client: autodie for pipe and socketpair Eric Wong
2023-10-17 23:37 ` [PATCH 13/30] xt/git-http-backend: remove Net::HTTP usage Eric Wong
2023-10-17 23:37 ` [PATCH 14/30] ds: introduce and use do_fork helper Eric Wong
2023-10-17 23:38 ` [PATCH 15/30] ds: get rid of SetLoopTimeout Eric Wong
2023-10-17 23:38 ` [PATCH 16/30] cindex: drop some unused functions Eric Wong
2023-10-17 23:38 ` [PATCH 17/30] syscall: common $F_SETPIPE_SZ definition Eric Wong
2023-10-17 23:38 ` [PATCH 18/30] t/lei-up: additional diagnostics for match failures Eric Wong
2023-10-17 23:38 ` [PATCH 19/30] test_common: use autodie and read_all where possible Eric Wong
2023-10-17 23:38 ` [PATCH 20/30] test_common: only hide TCP port in messages Eric Wong
2023-10-17 23:38 ` [PATCH 21/30] test_common: use $cwdfh for every run_script command Eric Wong
2023-10-17 23:38 ` [PATCH 22/30] init: drop extraneous `+' Eric Wong
2023-10-17 23:38 ` [PATCH 23/30] init: use autodie to reduce distractions Eric Wong
2023-10-17 23:38 ` [PATCH 24/30] xt/mem-imapd-tls: remove unused/broken epoll imports Eric Wong
2023-10-17 23:38 ` [PATCH 25/30] xt/mem-imapd-tls: reduce FDs for lsof use Eric Wong
2023-10-17 23:38 ` [PATCH 26/30] lei: use autodie where appropriate Eric Wong
2023-10-17 23:38 ` [PATCH 27/30] lei_auth: update comments and use v5.12 Eric Wong
2023-10-17 23:38 ` [PATCH 28/30] lei_config: drop redundant open check Eric Wong
2023-10-17 23:38 ` [PATCH 29/30] convert: use read_all to simplify error checks Eric Wong
2023-10-17 23:38 ` [PATCH 30/30] idx_stack: use autodie + read_all Eric Wong
2023-10-19 1:14 ` [PATCH 31/30] lei: simplify startq/au_done wakeup notifications Eric Wong
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