conf.c: fix handling of NULL ids

Make sure that we do not crash when encountering configuration nodes
with a NULL id.  Furthermore, since we cannot avoid having NULL ids
anyway, allow the id of a top-level node to be reset to NULL.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

diff --git a/src/conf.c b/src/conf.c
index c86f819b1e024280d7079a645630eb2482e42c30..ff9d4332ee1aaf67462aa378399471e917397bb3 100644 (file)
--- a/src/conf.c
+++ b/src/conf.c
@@ -1522,10 +1522,16 @@ int snd_config_get_id(const snd_config_t *config, const char **id)
 int snd_config_set_id(snd_config_t *config, const char *id)
 {
        char *new_id;
-       assert(config && id);
-       new_id = strdup(id);
-       if (!new_id)
-               return -ENOMEM;
+       assert(config);
+       if (id) {
+               new_id = strdup(id);
+               if (!new_id)
+                       return -ENOMEM;
+       } else {
+               if (config->father)
+                       return -EINVAL;
+               new_id = NULL;
+       }
        free(config->id);
        config->id = new_id;
        return 0;
@@ -1638,6 +1644,8 @@ int snd_config_add(snd_config_t *father, snd_config_t *leaf)
 {
        snd_config_iterator_t i, next;
        assert(father && leaf);
+       if (!leaf->id)
+               return -EINVAL;
        snd_config_for_each(i, next, father) {
                snd_config_t *n = snd_config_iterator_entry(i);
                if (strcmp(leaf->id, n->id) == 0)
@@ -2286,7 +2294,10 @@ int snd_config_get_ascii(const snd_config_t *config, char **ascii)
 int snd_config_test_id(const snd_config_t *config, const char *id)
 {
        assert(config && id);
-       return strcmp(config->id, id);
+       if (config->id)
+               return strcmp(config->id, id);
+       else
+               return -1;
 }
 
 /**
@@ -3350,7 +3361,7 @@ static int _snd_config_expand(snd_config_t *src,
        switch (pass) {
        case SND_CONFIG_WALK_PASS_PRE:
        {
-               if (strcmp(id, "@args") == 0)
+               if (id && strcmp(id, "@args") == 0)
                        return 0;
                err = snd_config_make_compound(dst, id, src->u.compound.join);
                if (err < 0)