[PATCH 1/2] util: Introduce set_cloexec()

[Michal Privoznik <mprivozn@redhat.com>]

This function is going to be used on FDs inherited from parent.
Parent can't set O_CLOEXEC obviously, so we have to set it
ourselves.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 util.c | 17 +++++++++++++++++
 util.h |  1 +
 2 files changed, 18 insertions(+)

diff --git a/util.c b/util.c
index 1d00404..9817c74 100644
--- a/util.c
+++ b/util.c
@@ -526,6 +526,23 @@ int write_file(const char *path, const char *buf)
 	return len == 0 ? 0 : -1;
 }
 
+/**
+ * set_cloexec() - Set Close-on-exec flag on given FD
+ * @fd:		FD to set the flag on
+ *
+ * Return: 0 on success, -1 on any error
+ */
+int set_cloexec(int fd)
+{
+	int fflags;
+	if ((fflags = fcntl(fd, F_GETFD)) < 0)
+		return -1;
+	fflags |= FD_CLOEXEC;
+	if ((fcntl(fd, F_SETFD, fflags)) < 0)
+		return -1;
+	return 0;
+}
+
 #ifdef __ia64__
 /* Needed by do_clone() below: glibc doesn't export the prototype of __clone2(),
  * use the description from clone(2).
diff --git a/util.h b/util.h
index 26892aa..3db901d 100644
--- a/util.h
+++ b/util.h
@@ -222,5 +222,6 @@ void write_pidfile(int fd, pid_t pid);
 int __daemon(int pidfile_fd, int devnull_fd);
 int fls(unsigned long x);
 int write_file(const char *path, const char *buf);
+int set_cloexec(int fd);
 
 #endif /* UTIL_H */
-- 
@@ -222,5 +222,6 @@ void write_pidfile(int fd, pid_t pid);
 int __daemon(int pidfile_fd, int devnull_fd);
 int fls(unsigned long x);
 int write_file(const char *path, const char *buf);
+int set_cloexec(int fd);
 
 #endif /* UTIL_H */
-- 
2.39.3