From d5c0a8c2f32ac96d4151bc94aa42d0bf06fdf4a9 Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@gmail.com>
Date: Fri, 18 Dec 2015 19:41:49 +0100
Subject: [PATCH] Support the case of an empty symlink

There is the report of a such condition in Windows.
---
 HISTORY         |  1 +
 cmdline/scan.c  |  2 ++
 cmdline/state.c | 20 ++++++++++++++++----
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/HISTORY b/HISTORY
index 07ababf7..23302423 100644
--- a/HISTORY
+++ b/HISTORY
@@ -3,6 +3,7 @@ SnapRAID HISTORY
 
 9.2 2015/12
 ===========
+ * Allows symlinks pointing to an empty target.
  * Adds UUID support to Btrfs filesystems. It's available only if the
    libblkid library is available on the system.
 
diff --git a/cmdline/scan.c b/cmdline/scan.c
index f428f842..43da04de 100644
--- a/cmdline/scan.c
+++ b/cmdline/scan.c
@@ -1325,6 +1325,8 @@ static int scan_dir(struct snapraid_scan* scan, int level, int is_diff, const ch
 					exit(EXIT_FAILURE);
 					/* LCOV_EXCL_STOP */
 				}
+				if (ret == 0)
+					log_fatal("WARNING! Empty symbolic link '%s'.\n", path_next);
 
 				/* readlink doesn't put the final 0 */
 				subnew[ret] = 0;
diff --git a/cmdline/state.c b/cmdline/state.c
index 424d997f..cc8acad9 100644
--- a/cmdline/state.c
+++ b/cmdline/state.c
@@ -1738,6 +1738,7 @@ static void state_read_content(struct snapraid_state* state, const char* path, S
 			if (!*sub) {
 				/* LCOV_EXCL_START */
 				decoding_error(path, f);
+				log_fatal("Internal inconsistency for null file!\n");
 				os_abort();
 				/* LCOV_EXCL_STOP */
 			}
@@ -2100,15 +2101,16 @@ static void state_read_content(struct snapraid_state* state, const char* path, S
 				/* LCOV_EXCL_STOP */
 			}
 
-			ret = sgetbs(f, linkto, sizeof(linkto));
-			if (ret < 0) {
+			if (!*sub) {
 				/* LCOV_EXCL_START */
 				decoding_error(path, f);
+				log_fatal("Internal inconsistency for null symlink!\n");
 				os_abort();
 				/* LCOV_EXCL_STOP */
 			}
 
-			if (!*sub || !*linkto) {
+			ret = sgetbs(f, linkto, sizeof(linkto));
+			if (ret < 0) {
 				/* LCOV_EXCL_START */
 				decoding_error(path, f);
 				os_abort();
@@ -2150,6 +2152,14 @@ static void state_read_content(struct snapraid_state* state, const char* path, S
 				/* LCOV_EXCL_STOP */
 			}
 
+			if (!*sub) {
+				/* LCOV_EXCL_START */
+				decoding_error(path, f);
+				log_fatal("Internal inconsistency for null hardlink!\n");
+				os_abort();
+				/* LCOV_EXCL_STOP */
+			}
+
 			ret = sgetbs(f, linkto, sizeof(linkto));
 			if (ret < 0) {
 				/* LCOV_EXCL_START */
@@ -2158,9 +2168,10 @@ static void state_read_content(struct snapraid_state* state, const char* path, S
 				/* LCOV_EXCL_STOP */
 			}
 
-			if (!*sub || !*linkto) {
+			if (!*linkto) {
 				/* LCOV_EXCL_START */
 				decoding_error(path, f);
+				log_fatal("Internal inconsistency for empty hardlink '%s'!\n", sub);
 				os_abort();
 				/* LCOV_EXCL_STOP */
 			}
@@ -2202,6 +2213,7 @@ static void state_read_content(struct snapraid_state* state, const char* path, S
 			if (!*sub) {
 				/* LCOV_EXCL_START */
 				decoding_error(path, f);
+				log_fatal("Internal inconsistency for null dir!\n");
 				os_abort();
 				/* LCOV_EXCL_STOP */
 			}