File 0011-0020-PLESK-sig-block-reexec.patch of Package scl-php73

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Julian Brown <julian.brown@cpanel.net>
Date: Tue, 7 May 2019 12:17:00 -0500
Subject: [PATCH 11/14] 0020-PLESK-sig-block-reexec

First of 3 patches for signal management.
---
 sapi/fpm/fpm/fpm_main.c        |  9 ++++++
 sapi/fpm/fpm/fpm_process_ctl.c |  4 +++
 sapi/fpm/fpm/fpm_signals.c     | 54 ++++++++++++++++++++++++++++++++++
 sapi/fpm/fpm/fpm_signals.h     |  3 ++
 4 files changed, 70 insertions(+)

diff --git a/sapi/fpm/fpm/fpm_main.c b/sapi/fpm/fpm/fpm_main.c
index 70d7a37..ba2a324 100644
--- a/sapi/fpm/fpm/fpm_main.c
+++ b/sapi/fpm/fpm/fpm_main.c
@@ -1596,6 +1596,15 @@ int main(int argc, char *argv[])
 								closes it.  in apache|apxs mode apache
 								does that for us!  thies@thieso.net
 								20000419 */
+
+	/* Subset of signals from fpm_signals_init_main() to avoid unexpected death during early init
+		or during reload just after execvp() or fork */
+	int init_signal_array[] = { SIGUSR1, SIGUSR2, SIGCHLD };
+	if (0 > fpm_signals_init_mask(init_signal_array, sizeof(init_signal_array)/sizeof(init_signal_array[0])) ||
+	    0 > fpm_signals_block()) {
+		zlog(ZLOG_WARNING, "Could die in the case of too early reload signal");
+	}
+	zlog(ZLOG_DEBUG, "Blocked some signals");
 #endif
 #endif
 
diff --git a/sapi/fpm/fpm/fpm_process_ctl.c b/sapi/fpm/fpm/fpm_process_ctl.c
index 17fbe8d..2bc0017 100644
--- a/sapi/fpm/fpm/fpm_process_ctl.c
+++ b/sapi/fpm/fpm/fpm_process_ctl.c
@@ -77,6 +77,10 @@ static void fpm_pctl_exit() /* {{{ */
 
 static void fpm_pctl_exec() /* {{{ */
 {
+	zlog(ZLOG_DEBUG, "Blocking some signals before reexec");
+	if (0 > fpm_signals_block()) {
+		zlog(ZLOG_WARNING, "concurrent reloads may be unstable");
+	}
 
 	zlog(ZLOG_NOTICE, "reloading: execvp(\"%s\", {\"%s\""
 			"%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s"
diff --git a/sapi/fpm/fpm/fpm_signals.c b/sapi/fpm/fpm/fpm_signals.c
index caf41e8..f10dac1 100644
--- a/sapi/fpm/fpm/fpm_signals.c
+++ b/sapi/fpm/fpm/fpm_signals.c
@@ -19,6 +19,7 @@
 #include "zlog.h"
 
 static int sp[2];
+static sigset_t block_sigset;
 
 const char *fpm_signal_names[NSIG + 1] = {
 #ifdef SIGHUP
@@ -210,6 +211,11 @@ int fpm_signals_init_main() /* {{{ */
 		zlog(ZLOG_SYSERROR, "failed to init signals: sigaction()");
 		return -1;
 	}
+
+	zlog(ZLOG_DEBUG, "Unblocking all signals");
+	if (0 > fpm_signals_unblock()) {
+		return -1;
+	}
 	return 0;
 }
 /* }}} */
@@ -250,3 +256,51 @@ int fpm_signals_get_fd() /* {{{ */
 	return sp[0];
 }
 /* }}} */
+
+int fpm_signals_init_mask(int *signum_array, size_t size) /* {{{ */
+{
+	size_t i = 0;
+	if (0 > sigemptyset(&block_sigset)) {
+		zlog(ZLOG_SYSERROR, "failed to prepare signal block mask: sigemptyset()");
+		return -1;
+	}
+	for (i = 0; i < size; ++i) {
+		int sig_i = signum_array[i];
+		if (0 > sigaddset(&block_sigset, sig_i)) {
+			if (sig_i <= NSIG && fpm_signal_names[sig_i] != NULL) {
+				zlog(ZLOG_SYSERROR, "failed to prepare signal block mask: sigaddset(%s)",
+					fpm_signal_names[sig_i]);
+			} else {
+				zlog(ZLOG_SYSERROR, "failed to prepare signal block mask: sigaddset(%d)", sig_i);
+			}
+			return -1;
+		}
+	}
+	return 0;
+}
+/* }}} */
+
+int fpm_signals_block() /* {{{ */
+{
+	if (0 > sigprocmask(SIG_BLOCK, &block_sigset, NULL)) {
+		zlog(ZLOG_SYSERROR, "failed to block signals");
+		return -1;
+	}
+	return 0;
+}
+/* }}} */
+
+int fpm_signals_unblock() /* {{{ */
+{
+	/* Ensure that during reload after upgrade all signals are unblocked.
+		block_sigset could have different value before execve() */
+	sigset_t all_signals;
+	sigfillset(&all_signals);
+	if (0 > sigprocmask(SIG_UNBLOCK, &all_signals, NULL)) {
+		zlog(ZLOG_SYSERROR, "failed to unblock signals");
+		return -1;
+	}
+	return 0;
+}
+/* }}} */
+
diff --git a/sapi/fpm/fpm/fpm_signals.h b/sapi/fpm/fpm/fpm_signals.h
index 7202816..6ce7277 100644
--- a/sapi/fpm/fpm/fpm_signals.h
+++ b/sapi/fpm/fpm/fpm_signals.h
@@ -8,6 +8,9 @@
 int fpm_signals_init_main();
 int fpm_signals_init_child();
 int fpm_signals_get_fd();
+int fpm_signals_init_mask(int *signum_array, size_t size);
+int fpm_signals_block();
+int fpm_signals_unblock();
 
 extern const char *fpm_signal_names[NSIG + 1];