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

[Sven Eckelmann <sven@narfation.org>]

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 <sven@narfation.org>
---
 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