fabrics: Explicitly initialize auto-cleanup variables

gcc complains about potentially	uninitialized variables used
in the cleanup function even though such scenario is unlikely
to happen. Still, an explicit initializer makes the warnings
go away.

E.g.

../src/nvme/fabrics.c: In function ‘nvmf_hostnqn_generate’:
../src/nvme/fabrics.c:1297:30: note: ‘stream’ was declared here
 1297 |         _cleanup_file_ FILE *stream;
      |                              ^~~~~~
In function ‘cleanup_fd’,
    inlined from ‘uuid_from_device_tree’ at ../src/nvme/fabrics.c:1189:19,
    inlined from ‘nvmf_hostnqn_generate’ at ../src/nvme/fabrics.c:1350:9:
../src/nvme/cleanup.h:37:17: warning: ‘f’ may be used uninitialized [-Wmaybe-uninitialized]
   37 |                 close(*fd);
      |                 ^~~~~~~~~~

Signed-off-by: Tomas Bzatek <[email protected]>

Author: tbzatek

src/nvme/fabrics.c

@@ -740,7 +740,7 @@ static  int __nvmf_supported_options(nvme_root_t r)
 
 static int __nvmf_add_ctrl(nvme_root_t r, const char *argstr)
 {
-	_cleanup_fd_ int fd;
+	_cleanup_fd_ int fd = -1;
 	int ret, len = strlen(argstr);
 	char buf[0x1000], *options, *p;
 
@@ -1186,7 +1186,7 @@ struct nvmf_discovery_log *nvmf_get_discovery_wargs(struct nvme_get_discovery_ar
 static int uuid_from_device_tree(char *system_uuid)
 {
 	ssize_t len;
-	_cleanup_fd_ int f;
+	_cleanup_fd_ int f = -1;
 
 	f = open(PATH_UUID_IBM, O_RDONLY);
 	if (f < 0)
@@ -1230,7 +1230,7 @@ static bool is_dmi_uuid_valid(const char *buf, size_t len)
 static int uuid_from_dmi_entries(char *system_uuid)
 {
 	int f;
-	_cleanup_dir_ DIR *d;
+	_cleanup_dir_ DIR *d = NULL;
 	struct dirent *de;
 	char buf[512] = {0};
 
@@ -1294,7 +1294,7 @@ static int uuid_from_dmi_entries(char *system_uuid)
  */
 static int uuid_from_product_uuid(char *system_uuid)
 {
-	_cleanup_file_ FILE *stream;
+	_cleanup_file_ FILE *stream = NULL;
 	ssize_t nread;
 	_cleanup_free_ char *line = NULL;
 	size_t len = 0;
@@ -1364,7 +1364,7 @@ char *nvmf_hostnqn_generate()
 static char *nvmf_read_file(const char *f, int len)
 {
 	char buf[len];
-	_cleanup_fd_ int fd;
+	_cleanup_fd_ int fd = -1;
 	int ret;
 
 	fd = open(f, O_RDONLY);
@@ -1637,7 +1637,7 @@ static const char *dctype_str[] = {
  */
 static int nvme_fetch_cntrltype_dctype_from_id(nvme_ctrl_t c)
 {
-	_cleanup_free_ struct nvme_id_ctrl *id;
+	_cleanup_free_ struct nvme_id_ctrl *id = NULL;
 	int ret;
 
 	id = __nvme_alloc(sizeof(*id));