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.
OpenRC · Sep 5, 2023 · e237f6d · e237f6d
1 parent 3b401d1
commit e237f6d
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Showing 3 changed files with 31 additions and 20 deletions.
diff --git 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
@@ -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
diff --git a/src/supervise-daemon/supervise-daemon.c b/src/supervise-daemon/supervise-daemon.c
@@ -22,11 +22,6 @@
 #define ONE_SECOND    1000000000
 #define ONE_MS           1000000
 
-#ifdef HAVE_CLOSE_RANGE
-/* For close_range() */
-# define _GNU_SOURCE
-#endif
-
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
@@ -203,18 +198,6 @@ static inline int ioprio_set(int which RC_UNUSED, int who RC_UNUSED,
 }
 #endif
 
-#ifndef CLOSE_RANGE_CLOEXEC
-# define CLOSE_RANGE_CLOEXEC	(1U << 2)
-#endif
-#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
-
 static void cleanup(void)
 {
 	free(changeuser);
@@ -582,9 +565,8 @@ RC_NORETURN static void child_process(char *exec, char **argv)
 	if (redirect_stderr || rc_yesno(getenv("EINFO_QUIET")))
 		dup2(stderr_fd, STDERR_FILENO);
 
-	if (close_range(3, UINT_MAX, CLOSE_RANGE_CLOEXEC) < 0)
-		for (i = getdtablesize() - 1; i >= 3; --i)
-			fcntl(i, F_SETFD, FD_CLOEXEC);
+	cloexec_fds_from(3);
+
 	cmdline = make_cmdline(argv);
 	syslog(LOG_INFO, "Child command line: %s", cmdline);
 	free(cmdline);