FPM. access.log with stderr begins to write logs to error_log after daemon reload (GH-8885)

sapi/fpm/fpm/fpm_events.c

@@ -104,6 +104,13 @@ static void fpm_got_signal(struct fpm_event_s *ev, short which, void *arg) /* {{
 				break;
 			case '1' :                  /* SIGUSR1 */
 				zlog(ZLOG_DEBUG, "received SIGUSR1");
+
+				/* fpm_stdio_init_final tied STDERR fd with error_log fd. This affects logging to the
+				 * access.log if it was configured to write to the stderr. Check #8885. */
+				if (0 > fpm_stdio_restore_original_stderr()) {
+					zlog(ZLOG_SYSERROR, "failed to restore original STDERR descriptor, access.log records may appear in the error_log");
+				}
+
 				if (0 == fpm_stdio_open_error_log(1)) {
 					zlog(ZLOG_NOTICE, "error log file re-opened");
 				} else {
@@ -118,6 +125,9 @@ static void fpm_got_signal(struct fpm_event_s *ev, short which, void *arg) /* {{
 				}
 				/* else no access log are set */
 
+				/* We need to tie stderr with error_log in the master process after log files reload. Check #8885. */
+				fpm_stdio_init_final();
+
 				break;
 			case '2' :                  /* SIGUSR2 */
 				zlog(ZLOG_DEBUG, "received SIGUSR2");

sapi/fpm/fpm/fpm_process_ctl.c

@@ -18,6 +18,7 @@
 #include "fpm_worker_pool.h"
 #include "fpm_scoreboard.h"
 #include "fpm_sockets.h"
+#include "fpm_stdio.h"
 #include "zlog.h"
 
 
@@ -82,6 +83,10 @@ static void fpm_pctl_exec(void) /* {{{ */
 		zlog(ZLOG_WARNING, "concurrent reloads may be unstable");
 	}
 
+	if (0 > fpm_stdio_restore_original_stderr()) {
+		zlog(ZLOG_SYSERROR, "failed to restore original STDERR descriptor, access.log and slowlog records may appear in error_log");
+	}
+
 	zlog(ZLOG_NOTICE, "reloading: execvp(\"%s\", {\"%s\""
 			"%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s"
 			"%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s" "%s%s%s"

sapi/fpm/fpm/fpm_stdio.c

@@ -20,6 +20,7 @@
 #include "fpm_stdio.h"
 #include "zlog.h"
 
+static int fd_stderr_original = -1;
 static int fd_stdout[2];
 static int fd_stderr[2];
 
@@ -67,6 +68,12 @@ int fpm_stdio_init_final() /* {{{ */
 		/* prevent duping if logging to syslog */
 		if (fpm_globals.error_log_fd > 0 && fpm_globals.error_log_fd != STDERR_FILENO) {
 
+			/* php-fpm loses STDERR fd after call of the dup2 below. Check #8555. */
+			if (0 > fpm_stdio_save_original_stderr()) {
+				zlog(ZLOG_SYSERROR, "failed to save original STDERR descriptor, access.log records may appear in error_log");
+				return -1;
+			}
+
 			/* there might be messages to stderr from other parts of the code, we need to log them all */
 			if (0 > dup2(fpm_globals.error_log_fd, STDERR_FILENO)) {
 				zlog(ZLOG_SYSERROR, "failed to init stdio: dup2()");
@@ -85,6 +92,33 @@ int fpm_stdio_init_final() /* {{{ */
 }
 /* }}} */
 
+int fpm_stdio_save_original_stderr(void) /* {{{ */
+{
+	zlog(ZLOG_DEBUG, "saving original STDERR fd: dup()");
+	fd_stderr_original = dup(STDERR_FILENO);
+	return fd_stderr_original;
+}
+/* }}} */
+
+int fpm_stdio_restore_original_stderr(void) /* {{{ */
+{
+	zlog(ZLOG_DEBUG, "restoring original STDERR fd: dup2()");
+	if (-1 != fd_stderr_original) {
+		zlog(ZLOG_DEBUG, "restoring original STDERR fd: dup2()");
+		if (0 > dup2(fd_stderr_original, STDERR_FILENO)) {
+			return -1;
+		} else {
+			close(fd_stderr_original);
+		}
+	} else {
+		zlog(ZLOG_DEBUG, "original STDERR fd is not restored, maybe function is called from a child: dup2()");
+		return -1;
+	}
+
+	return 0;
+}
+/* }}} */
+
 int fpm_stdio_init_child(struct fpm_worker_pool_s *wp) /* {{{ */
 {
 #ifdef HAVE_SYSLOG_H
@@ -336,10 +370,6 @@ int fpm_stdio_open_error_log(int reopen) /* {{{ */
 	}
 
 	if (reopen) {
-		if (fpm_use_error_log()) {
-			dup2(fd, STDERR_FILENO);
-		}
-
 		dup2(fd, fpm_globals.error_log_fd);
 		close(fd);
 		fd = fpm_globals.error_log_fd; /* for FD_CLOSEXEC to work */

sapi/fpm/fpm/fpm_stdio.h

@@ -16,5 +16,7 @@ void fpm_stdio_child_use_pipes(struct fpm_child_s *child);
 int fpm_stdio_parent_use_pipes(struct fpm_child_s *child);
 int fpm_stdio_discard_pipes(struct fpm_child_s *child);
 int fpm_stdio_open_error_log(int reopen);
+int fpm_stdio_save_original_stderr(void);
+int fpm_stdio_restore_original_stderr(void);
 
 #endif