From f84f2db69203d950c15dbb2f1748052f7b4a2b41 Mon Sep 17 00:00:00 2001
From: Nikolaus Rath <Nikolaus@rath.org>
Date: Mon, 24 Oct 2016 21:09:00 -0700
Subject: [PATCH] Fix segfault in debug logging code

fi may be NULL, so we need to protect against this.
---
 lib/fuse.c            | 49 ++++++++++++++++++++++++++++---------------
 test/test_examples.py |  5 ++++-
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/lib/fuse.c b/lib/fuse.c
index df6e3a0..692f9c5 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -1510,14 +1510,26 @@ static inline void fuse_prepare_interrupt(struct fuse *f, fuse_req_t req,
 		fuse_do_prepare_interrupt(req, d);
 }
 
+static const char* file_info_string(struct fuse_file_info *fi,
+			      char* buf, size_t len)
+{
+	if(fi == NULL)
+		return "NULL";
+	snprintf(buf, len, "%llu", (unsigned long long) fi->fh);
+	return buf;
+}
+
 int fuse_fs_getattr(struct fuse_fs *fs, const char *path, struct stat *buf,
 		    struct fuse_file_info *fi)
 {
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.getattr) {
-		if (fs->debug)
-			fprintf(stderr, "getattr[%llu] %s\n",
-				(unsigned long long) fi->fh, path);
+		if (fs->debug) {
+			char buf[10];
+			fprintf(stderr, "getattr[%s] %s\n",
+				file_info_string(fi, buf, sizeof(buf)),
+				path);
+		}
 		return fs->op.getattr(path, buf, fi);
 	} else {
 		return -ENOSYS;
@@ -1982,11 +1994,12 @@ int fuse_fs_chown(struct fuse_fs *fs, const char *path, uid_t uid,
 {
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.chown) {
-		if (fs->debug)
-			fprintf(stderr, "chown[%llu] %s %lu %lu\n",
-				(unsigned long long) fi->fh, path,
-				(unsigned long) uid, (unsigned long) gid);
-
+		if (fs->debug) {
+			char buf[10];
+			fprintf(stderr, "chown[%s] %s %lu %lu\n",
+				file_info_string(fi, buf, sizeof(buf)),
+				path, (unsigned long) uid, (unsigned long) gid);
+		}
 		return fs->op.chown(path, uid, gid, fi);
 	} else {
 		return -ENOSYS;
@@ -1998,11 +2011,12 @@ int fuse_fs_truncate(struct fuse_fs *fs, const char *path, off_t size,
 {
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.truncate) {
-		if (fs->debug)
-			fprintf(stderr, "truncate[%llu] %llu\n",
-				(unsigned long long) fi->fh,
+		if (fs->debug) {
+			char buf[10];
+			fprintf(stderr, "truncate[%s] %llu\n",
+				file_info_string(fi, buf, sizeof(buf)),
 				(unsigned long long) size);
-
+		}
 		return fs->op.truncate(path, size, fi);
 	} else {
 		return -ENOSYS;
@@ -2014,12 +2028,13 @@ int fuse_fs_utimens(struct fuse_fs *fs, const char *path,
 {
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.utimens) {
-		if (fs->debug)
-			fprintf(stderr, "utimens[%llu] %s %li.%09lu %li.%09lu\n",
-				(unsigned long long) fi->fh, path,
-				tv[0].tv_sec, tv[0].tv_nsec,
+		if (fs->debug) {
+			char buf[10];
+			fprintf(stderr, "utimens[%s] %s %li.%09lu %li.%09lu\n",
+				file_info_string(fi, buf, sizeof(buf)),
+				path, tv[0].tv_sec, tv[0].tv_nsec,
 				tv[1].tv_sec, tv[1].tv_nsec);
-
+		}
 		return fs->op.utimens(path, tv, fi);
 	} else {
 		return -ENOSYS;
diff --git a/test/test_examples.py b/test/test_examples.py
index 5c611a1..457c2a0 100755
--- a/test/test_examples.py
+++ b/test/test_examples.py
@@ -60,13 +60,16 @@ def test_hello(tmpdir, name, options):
 
 @pytest.mark.parametrize("name", ('passthrough', 'passthrough_fh',
                                   'passthrough_ll'))
-def test_passthrough(tmpdir, name):
+@pytest.mark.parametrize("debug", (True, False))
+def test_passthrough(tmpdir, name, debug):
     mnt_dir = str(tmpdir.mkdir('mnt'))
     src_dir = str(tmpdir.mkdir('src'))
 
     cmdline = base_cmdline + \
               [ pjoin(basename, 'example', name),
                 '-f', mnt_dir ]
+    if debug:
+        cmdline.append('-d')
     mount_process = subprocess.Popen(cmdline)
     try:
         wait_for_mount(mount_process, mnt_dir)
-- 
2.30.2