1 files changed, 72 insertions, 0 deletions
diff --git a/src/util/sane_link.c b/src/util/sane_link.c
new file mode 100644
index 0000000..de83564
--- /dev/null
+++ b/src/util/sane_link.c
@@ -0,0 +1,72 @@
+/*++
+/* NAME
+/*	sane_link 3
+/* SUMMARY
+/*	sanitize link() error returns
+/* SYNOPSIS
+/*	#include <sane_fsops.h>
+/*
+/*	int	sane_link(from, to)
+/*	const char *from;
+/*	const char *to;
+/* DESCRIPTION
+/*	sane_link() implements the link(2) system call, and works
+/*	around some errors that are possible with NFS file systems.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include "sys_defs.h"
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* Utility library. */
+
+#include "msg.h"
+#include "sane_fsops.h"
+#include "warn_stat.h"
+
+/* sane_link - sanitize link() error returns */
+
+int     sane_link(const char *from, const char *to)
+{
+    const char *myname = "sane_link";
+    int     saved_errno;
+    struct stat from_st;
+    struct stat to_st;
+
+    /*
+     * Normal case: link() succeeds.
+     */
+    if (link(from, to) >= 0)
+	return (0);
+
+    /*
+     * Woops. Save errno, and see if the error is an NFS artefact. If it is,
+     * pretend the error never happened.
+     */
+    saved_errno = errno;
+    if (stat(from, &from_st) >= 0 && stat(to, &to_st) >= 0
+	&& from_st.st_dev == to_st.st_dev
+	&& from_st.st_ino == to_st.st_ino) {
+	msg_info("%s(%s,%s): worked around spurious NFS error",
+		 myname, from, to);
+	return (0);
+    }
+
+    /*
+     * Nope, it didn't. Restore errno and report the error.
+     */
+    errno = saved_errno;
+    return (-1);
+}