[PATCH] batctl: don't stop on missing batman-adv version file

The system doesn't have to expose the /sys/module/batman_adv/version to the
userspace. This can either happen because:

* batman-adv was not loaded
* container doesn't expose the root namespace's /sys/modules
* distribution (like OpenWrt with `CONFIG_MODULE_STRIPPED`) decided to
  strip out this information and therefore the file
* kernel removed the version support at all
* ...

The check does therefore more harm and is not helping a lot to identify the
a missing batman-adv kernel module.

Signed-off-by: Sven Eckelmann <[email protected]>
---
 functions.c | 12 ------------
 functions.h |  1 -
 interface.c | 11 -----------
 main.c      |  4 ++--
 main.h      |  2 --
 5 files changed, 2 insertions(+), 28 deletions(-)

diff --git a/functions.c b/functions.c
index f7a3080..771b065 100644
--- a/functions.c
+++ b/functions.c
@@ -110,20 +110,8 @@ char *get_name_by_macstr(char *mac_str, int read_opt)
 	return get_name_by_macaddr(mac_addr, read_opt);
 }
 
-int file_exists(const char *fpath)
-{
-	struct stat st;
-
-	return stat(fpath, &st) == 0;
-}
-
 static void file_open_problem_dbg(const char *full_path)
 {
-	if (!file_exists(module_ver_path)) {
-		fprintf(stderr, "Error - batman-adv module has not been loaded\n");
-		return;
-	}
-
 	fprintf(stderr, "Error - can't open file '%s': %s\n", full_path, strerror(errno));
 	fprintf(stderr,
 		"The option you called seems not to be compiled into your batman-adv kernel module.\n");
diff --git a/functions.h b/functions.h
index 33b57da..c2ce1b8 100644
--- a/functions.h
+++ b/functions.h
@@ -42,7 +42,6 @@ double end_timer(void);
 char *ether_ntoa_long(const struct ether_addr *addr);
 char *get_name_by_macaddr(struct ether_addr *mac_addr, int read_opt);
 char *get_name_by_macstr(char *mac_str, int read_opt);
-int file_exists(const char *fpath);
 int read_file(const char *full_path, int read_opt);
 struct ether_addr *translate_mac(struct state *state,
 				 const struct ether_addr *mac);
diff --git a/interface.c b/interface.c
index dfe5ad4..dc77ad4 100644
--- a/interface.c
+++ b/interface.c
@@ -154,11 +154,6 @@ static int print_interfaces(struct state *state)
 {
 	int ret;
 
-	if (!file_exists(module_ver_path)) {
-		fprintf(stderr, "Error - batman-adv module has not been loaded\n");
-		return EXIT_FAILURE;
-	}
-
 	/* duplicated code here from the main() because interface doesn't always
 	 * need COMMAND_FLAG_MESH_IFACE and COMMAND_FLAG_NETLINK
 	 */
@@ -524,12 +519,6 @@ static int interface(struct state *state, int argc, char **argv)
 		goto err;
 	}
 
-	/* make sure that batman-adv is loaded or was loaded by create_interface */
-	if (!file_exists(module_ver_path)) {
-		fprintf(stderr, "Error - batman-adv module has not been loaded\n");
-		goto err;
-	}
-
 	pre_cnt = count_interfaces(state->mesh_iface);
 
 	for (i = 1; i < rest_argc; i++) {
diff --git a/main.c b/main.c
index 9516dee..921b3af 100644
--- a/main.c
+++ b/main.c
@@ -20,7 +20,7 @@
 #include "netlink.h"
 
 char mesh_dfl_iface[] = "bat0";
-char module_ver_path[] = "/sys/module/batman_adv/version";
+static const char module_ver_path[] = "/sys/module/batman_adv/version";
 
 extern const struct command *__start___command[];
 extern const struct command *__stop___command[];
@@ -138,7 +138,7 @@ static void version(void)
 	if (ret == EXIT_SUCCESS)
 		printf("%s]\n", line_ptr);
 	else
-		printf("module not loaded]\n");
+		printf("module version unknown]\n");
 
 	free(line_ptr);
 	exit(EXIT_SUCCESS);
diff --git a/main.h b/main.h
index bbac4c2..e6a08d3 100644
--- a/main.h
+++ b/main.h
@@ -33,8 +33,6 @@
 #define __maybe_unused __attribute__((unused))
 #define BIT(nr)                 (1UL << (nr)) /* linux kernel compat */
 
-extern char module_ver_path[];
-
 #ifndef VLAN_VID_MASK
 #define VLAN_VID_MASK   0xfff
 #endif

---
base-commit: a77a273d30a2fff8027e0b2382b4759740435f8c
change-id: 20260515-no-version-file-check-7f5b797c430c

Best regards,
--  
Sven Eckelmann <[email protected]>