From: Roy Marples <roy@marples.name>
Date: Fri, 29 Nov 2019 22:07:08 +0000 (+0000)
Subject: common: add close_std
X-Git-Tag: v9.0.0~193
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=608c60a2ab01efacf941ad313038f024f66107cc;p=thirdparty%2Fdhcpcd.git

common: add close_std

Closed stdin, stdout and stderr.
---

diff --git a/src/common.c b/src/common.c
index 8b45a307..6a686b8c 100644
--- a/src/common.c
+++ b/src/common.c
@@ -30,6 +30,8 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -41,6 +43,24 @@
 /* Most route(4) messages are less than 256 bytes. */
 #define IOVEC_BUFSIZ	256
 
+int
+close_std(void)
+{
+	int fd, error = 0;
+
+	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
+		return -1;
+
+	if (dup2(fd, STDIN_FILENO) == -1)
+		error = -1;
+	if (dup2(fd, STDOUT_FILENO) == -1)
+		error = -1;
+	if (dup2(fd, STDERR_FILENO) == -1)
+		error = -1;
+	close(fd);
+	return error;
+}
+
 const char *
 hwaddr_ntoa(const void *hwaddr, size_t hwlen, char *buf, size_t buflen)
 {
diff --git a/src/common.h b/src/common.h
index 4e8bcdea..44566c25 100644
--- a/src/common.h
+++ b/src/common.h
@@ -190,6 +190,7 @@
 # endif
 #endif
 
+int close_std(void);
 void get_line_free(void);
 extern int clock_monotonic;
 int get_monotonic(struct timespec *);