aplay/jack: avoid using alloca/strdup

+ small related improvements

Author: MartinPulec

src/audio/playback/jack.c

@@ -153,16 +153,14 @@ static void audio_play_jack_help(const char *client_name)
 
 static void * audio_play_jack_init(const char *cfg)
 {
-        struct state_jack_playback *s;
         const char **ports;
         jack_status_t status;
-        char *client_name;
+        char client_name[STR_LEN];
         const char *source_name = "";
 
-        client_name = alloca(MAX(strlen(PACKAGE_NAME), strlen(cfg)) + 1);
-        strcpy(client_name, PACKAGE_NAME);
+        snprintf_ch(client_name, "%s", PACKAGE_NAME);
 
-        s = calloc(1, sizeof(struct state_jack_playback));
+        struct state_jack_playback *s = calloc(1, sizeof(*s));
         if(!s) {
                 log_msg(LOG_LEVEL_ERROR, MOD_NAME "Unable to allocate memory.\n");
                 return NULL;
@@ -174,16 +172,16 @@ static void * audio_play_jack_init(const char *cfg)
                 return NULL;
         }
 
-        char *dup = strdup(cfg);
-        assert(dup != NULL);
+        char dup[STR_LEN];
+        snprintf_ch(dup, "%s", cfg);
         char *tmp = dup, *item, *save_ptr;
         while ((item = strtok_r(tmp, ":", &save_ptr)) != NULL) {
                 if (strcmp(item, "help") == 0) {
                         audio_play_jack_help(client_name);
                         free(s);
-                        free(dup);
                         return INIT_NOERR;
-                } else if (strstr(item, "first_channel=") == item) {
+                }
+                if (strstr(item, "first_channel=") == item) {
                         char *endptr;
                         char *val = item + strlen("first_channel=");
                         errno = 0;
@@ -200,8 +198,6 @@ static void * audio_play_jack_init(const char *cfg)
                 }
                 tmp = NULL;
         }
-        free(dup);
-        dup = NULL;
 
         s->jack_ports_pattern = strdup(source_name);
 
@@ -253,7 +249,6 @@ static void * audio_play_jack_init(const char *cfg)
         s->libjack->client_close(s->client);
 error:
         close_libjack(s->libjack);
-        free(dup);
         free(s);
         return NULL;
 }