From: Roy Marples <roy@marples.name>
Date: Fri, 6 Sep 2019 11:52:22 +0000 (+0100)
Subject: DHCP: If root fs is network mounted, enable last lease extend
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d68b260c745008426e8411121325b6cf4d038ddd;p=thirdparty%2Fdhcpcd.git

DHCP: If root fs is network mounted, enable last lease extend

We don't want expiry to unmount the root FS.
Also, we don't want a reboot with an expired lease to kill
our current assignment either.

Only works on NetBSD right now.
---

diff --git a/src/common.c b/src/common.c
index 838b4887..8b45a307 100644
--- a/src/common.c
+++ b/src/common.c
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#include <sys/statvfs.h>
+
 #include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
@@ -135,3 +137,18 @@ read_hwaddr_aton(uint8_t **data, const char *path)
 	fclose(fp);
 	return len;
 }
+
+int
+is_root_local(void)
+{
+#ifdef ST_LOCAL
+	struct statvfs vfs;
+
+	if (statvfs("/", &vfs) == -1)
+		return -1;
+	return vfs.f_flag & ST_LOCAL ? 1 : 0;
+#else
+	errno = ENOTSUP;
+	return -1;
+#endif
+}
diff --git a/src/common.h b/src/common.h
index 301c8869..4e8bcdea 100644
--- a/src/common.h
+++ b/src/common.h
@@ -197,4 +197,5 @@ int get_monotonic(struct timespec *);
 const char *hwaddr_ntoa(const void *, size_t, char *, size_t);
 size_t hwaddr_aton(uint8_t *, const char *);
 size_t read_hwaddr_aton(uint8_t **, const char *);
+int is_root_local(void);
 #endif
diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index 6d361e49..f944d9e6 100644
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -590,6 +590,12 @@ configure_interface1(struct interface *ifp)
 		}
 	}
 #endif
+
+	/* If root is network mounted, we don't want to kill the connection
+	 * if the DHCP server goes the way of the dodo OR dhcpcd is rebooting
+	 * and the lease file has expired. */
+	if (is_root_local() == 0)
+		ifo->options |= DHCPCD_LASTLEASE_EXTEND;
 }
 
 int