From c199c5cf6e39d6e21b92bddba7beeebcc3afca79 Mon Sep 17 00:00:00 2001
From: Natanael Copa <ncopa@alpinelinux.org>
Date: Wed, 30 Aug 2023 13:17:07 +0200
Subject: misc: add cloexec_fds_from() helper function

Move logic to set file descriptors to a cloexec_fds_from() function in
misc.c so it can be shared by both supervisor-daemon and
start-stop-daemon, and hide the details behind.
---
 src/shared/misc.c | 27 +++++++++++++++++++++++++++
 src/shared/misc.h |  2 ++
 2 files changed, 29 insertions(+)

(limited to 'src/shared')

diff --git a/src/shared/misc.c b/src/shared/misc.c
index c987ce8c..429407d4 100644
--- a/src/shared/misc.c
+++ b/src/shared/misc.c
@@ -15,6 +15,11 @@
  *    except according to the terms contained in the LICENSE file.
  */
 
+#ifdef HAVE_CLOSE_RANGE
+/* For close_range() */
+# define _GNU_SOURCE
+#endif
+
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -500,3 +505,25 @@ pid_t get_pid(const char *applet,const char *pidfile)
 
 	return pid;
 }
+
+#ifndef HAVE_CLOSE_RANGE
+static inline int close_range(int first RC_UNUSED,
+			      int last RC_UNUSED,
+			      unsigned int flags RC_UNUSED)
+{
+	return -1;
+}
+#endif
+#ifndef CLOSE_RANGE_CLOEXEC
+# define CLOSE_RANGE_CLOEXEC	(1U << 2)
+#endif
+
+void
+cloexec_fds_from(int first)
+{
+	int i;
+	if (close_range(first, UINT_MAX, CLOSE_RANGE_CLOEXEC) < 0) {
+		for (i = getdtablesize() - 1; i >= first; --i)
+			fcntl(i, F_SETFD, FD_CLOEXEC);
+	}
+}
diff --git a/src/shared/misc.h b/src/shared/misc.h
index f4ab25ad..b158a786 100644
--- a/src/shared/misc.h
+++ b/src/shared/misc.h
@@ -73,4 +73,6 @@ void from_time_t(char *time_string, time_t tv);
 time_t to_time_t(char *timestring);
 pid_t get_pid(const char *applet, const char *pidfile);
 
+void cloexec_fds_from(int);
+
 #endif
-- 
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