From e85f72300043f96e3f352d9c8f93243d4d0a52dc Mon Sep 17 00:00:00 2001
From: hjl <hjl>
Date: Tue, 15 Oct 2002 16:21:06 +0000
Subject: [PATCH] 2002-10-15  Juan Gomez <juang@us.ibm.com>

	* utils/mountd/rmtab.c (slink_safe_rename): New. Support
	symlink.
	(mountlist_add): Call slink_safe_rename instead of rename.
---
 ChangeLog            |  6 ++++++
 utils/mountd/rmtab.c | 40 ++++++++++++++++++++++++++++++++++++++--
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 1567d82..a050952 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2002-10-15  Juan Gomez <juang@us.ibm.com>
+
+	* utils/mountd/rmtab.c (slink_safe_rename): New. Support
+	symlink.
+	(mountlist_add): Call slink_safe_rename instead of rename.
+
 2002-10-11  H.J. Lu <hjl@lucon.org>
 
 	* support/include/exportfs.h (export_errno): New.
diff --git a/utils/mountd/rmtab.c b/utils/mountd/rmtab.c
index 170d859..0a4ed4c 100644
--- a/utils/mountd/rmtab.c
+++ b/utils/mountd/rmtab.c
@@ -8,7 +8,9 @@
 
 #include "config.h"
 
+#include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>
@@ -18,6 +20,40 @@
 #include "xio.h"
 #include "mountd.h"
 
+#include <limits.h> /* PATH_MAX */
+
+/* If new path is a link do not destroy it but place the
+ * file where the link points.
+ */
+
+static int 
+slink_safe_rename(const char * oldpath, const char * newpath)
+{
+  int r;
+  struct stat s;
+  char slink_path[PATH_MAX];
+  char real_newpath = newpath;
+
+  if((lstat(newpath, &s) == 0) && (S_ISLNK(s.st_mode))) {
+
+    /* New path is a symbolic link, do not destroy but follow */
+
+    if((r = readlink(newpath, slink_path, PATH_MAX))==-1) {
+
+      return -1;
+
+    }
+
+    slink_path[ (r < PATH_MAX) ? (r + 1) : (PATH_MAX - 1)] = '\0';
+
+    real_newpath = slink_path;
+
+  }
+
+  return rename(oldpath, real_newpath);
+
+}/* static int slink_safe_rename() */
+
 void
 mountlist_add(nfs_export *exp, const char *path)
 {
@@ -82,7 +118,7 @@ mountlist_del(nfs_export *exp, const char *path)
 		if (!match || rep->r_count)
 			fputrmtabent(fp, rep, NULL);
 	}
-	if (rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
+	if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
 		xlog(L_ERROR, "couldn't rename %s to %s",
 				_PATH_RMTABTMP, _PATH_RMTAB);
 	}
@@ -130,7 +166,7 @@ mountlist_del_all(struct sockaddr_in *sin)
 		}
 		fputrmtabent(fp, rep, NULL);
 	}
-	if (rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
+	if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
 		xlog(L_ERROR, "couldn't rename %s to %s",
 				_PATH_RMTABTMP, _PATH_RMTAB);
 	}
-- 
2.39.5