[PATCH 2/8] alfred: vis: keep interface names always in heap

The interface pointer in globals was used to store an address in .rodata or
in on the heap. This makes the handling of the allocation/deallocation
hard. At the same time, nothing checked for allocations problems. An
allocation error could cause an hard-to-debug problem later when trying to
calculate the ifindex.

Adjust the code to always allocate the string as an heap object to simplify
the handling.

Fixes: 2e3e312f7757 ("alfred: add vis")
Signed-off-by: Sven Eckelmann <[email protected]>
---
 vis/vis.c | 12 +++++++++++-
 vis/vis.h |  2 +-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/vis/vis.c b/vis/vis.c
index d635798..97c6093 100644
--- a/vis/vis.c
+++ b/vis/vis.c
@@ -1058,10 +1058,15 @@ static struct globals *vis_init(int argc, char *argv[])
 	memset(globals, 0, sizeof(*globals));
 
 	globals->opmode = OPMODE_CLIENT;
-	globals->interface = "bat0";
 	globals->vis_format = FORMAT_DOT;
 	globals->unix_path = ALFRED_SOCK_PATH_DEFAULT;
 
+	globals->interface = strdup("bat0");
+	if (!globals->interface) {
+		perror("strdup");
+		return NULL;
+	}
+
 	while ((opt = getopt_long(argc, argv, "shf:i:vu:", long_options,
 				  &opt_ind)) != -1) {
 		switch (opt) {
@@ -1081,7 +1086,12 @@ static struct globals *vis_init(int argc, char *argv[])
 			}
 			break;
 		case 'i':
+			free(globals->interface);
 			globals->interface = strdup(optarg);
+			if (!globals->interface) {
+				perror("strdup");
+				return NULL;
+			}
 			break;
 		case 'u':
 			globals->unix_path = optarg;
diff --git a/vis/vis.h b/vis/vis.h
index e257c45..d3486f9 100644
--- a/vis/vis.h
+++ b/vis/vis.h
@@ -73,7 +73,7 @@ struct vis_list_entry {
 	 (vis_data)->entries_n * sizeof(struct vis_entry))
 
 struct globals {
-	const char *interface;
+	char *interface;
 	enum opmode opmode;
 	enum vis_format vis_format;
 	uint8_t buf[65536];

-- 
2.47.3