fix: solve leak sanitizer on graceful shutdown

I am testing by simply calling `pipeline_cancel` on the first pipeline
execution.

include/pipeline.h

@@ -38,8 +38,10 @@ typedef struct {
 
 // create a new pipeline_conf struct instance based on a configuration line.
 optional_pipeline_conf pipeline_create(const char* config_line);
+void pipeline_event_destroy(pipeline_event* ev);
 void pipeline_destroy(pipeline_conf* conf);
 void pipeline_register(pthread_t thread);
 void pipeline_loop();
+void pipeline_cancel();
 
 #endif

src/executor.c

@@ -152,7 +152,7 @@ end:
     argv_free(argv);
     close(fd.value);
     free(pipeline_id);
-    free(data);
+    pipeline_event_destroy(data);
     char** cursor = envp;
     while(*cursor != NULL) {
         free(*cursor);

src/main.c

@@ -26,21 +26,26 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 
-threadpool* pool = NULL;
+threadpool* worker_pool = NULL;
 char* trigger_dir = "/tmp/sci";
 bool config_file_changed = false;
 
 void on_event(pipeline_event* const e) {
-    if(!threadpool_add_work(pool, executor, (void*)e))
+    if(!threadpool_add_work(worker_pool, executor, (void*)e))
         log_error("could not add work to the threadpool");
 }
 
+void listener_thread_cleanup(void* data) {
+    // We're now done with the config.
+    pipeline_destroy((pipeline_conf*)data);
+}
+
 void* listen_for_changes_thread(void* data) {
     pipeline_conf* conf = (pipeline_conf*)data;
-    while(1) // TODO: Should be while(sigint_has_not_been_caught) instead
+    pthread_cleanup_push(listener_thread_cleanup, conf);
+    while(1)
         listen_for_changes(conf, &on_event);
-    // We're now done with the config.
+    pthread_cleanup_pop(1);
-    pipeline_destroy(conf);
     return NULL;
 }
 

src/notify.c

@@ -24,7 +24,7 @@
 #define BUF_LEN EV_SIZE * 32
 
 void listen_for_changes(const pipeline_conf* config, notify_callback callback) {
-    // TODO: callback is a bit slow sometimes. We should also poll once after calling callback
+    // TODO: callback is potentially slow. We should also poll once after calling callback
     const char* filename = config->trigger;
     if(access(filename, F_OK) != 0) {
         log_trace("file does not exist yet, creating it.");
@@ -37,17 +37,43 @@ void listen_for_changes(const pipeline_conf* config, notify_callback callback) {
     log_trace("listening for changes in file: %s", filename);
     char buffer[BUF_LEN];
     int r = read(fd, buffer, BUF_LEN);
-    assert(r != -1);
+    if(r == -1) {
+        perror("read");
+        return;
+    }
     for(int i = 0; i < r; ) {
         struct inotify_event* e = (struct inotify_event*)&buffer[i];
         pipeline_event* ev = malloc(sizeof(pipeline_event));
         ev->event = e;
-        ev->name = config->name;
+        ev->name = strdup(config->name);
-        ev->url = config->url;
+        ev->url = strdup(config->url);
-        ev->trigger = config->trigger;
+        ev->trigger = strdup(config->trigger);
-        ev->command = config->command;
+        ev->command = strdup(config->command);
         callback(ev);
         i += EV_SIZE + e->len;
     }
     ASSERT_SYSCALL_SUCCESS(close(fd));
 }
+
+void listen_for_config_changes(const char* config_filepath, config_change_callback callback) {
+    if(access(config_filepath, F_OK) != 0) {
+        perror("access");
+        return;
+    }
+    int fd = inotify_init();
+    ASSERT_SYSCALL_SUCCESS(fd);
+    inotify_add_watch(fd, config_filepath, IN_ATTRIB);
+    log_trace("listening for changes in file: %s", config_filepath);
+    char buffer[BUF_LEN];
+    int r = read(fd, buffer, BUF_LEN);
+    if(r == -1) {
+        perror("read");
+        return;
+    }
+    assert(r != -1);
+    for(int i = 0; i < r; ) {
+        callback();
+        i += EV_SIZE + ((struct inotify_event*)&buffer[i])->len;;
+    }
+    ASSERT_SYSCALL_SUCCESS(close(fd));
+}

src/pipeline.c

@@ -19,6 +19,7 @@
 #include "pipeline.h"
 #include "threadlist.h"
 #include "util.h"
+#include <pthread.h>
 #include <regex.h>
 #include <stdlib.h>
 
@@ -54,6 +55,7 @@ optional_pipeline_conf pipeline_create(const char* config_line) {
             free(opts[j]);
         return result;
     }
+    regfree(&reg);
 
     result.value = malloc(sizeof(pipeline_conf));
     result.value->name = opts[0];
@@ -89,3 +91,19 @@ void pipeline_loop() {
     clear_thread_list(root);
     root = NULL;
 }
+
+void pipeline_cancel() {
+    pthread_list_node* cursor = root;
+    while(cursor != NULL) {
+        pthread_cancel(cursor->thread);
+        cursor = cursor->next;
+    }
+}
+
+void pipeline_event_destroy(pipeline_event* ev) {
+    free(ev->name);
+    free(ev->trigger);
+    free(ev->url);
+    free(ev->command);
+    free(ev);
+}

src/threadlist.c

@@ -71,7 +71,8 @@ void clear_thread_list(pthread_list_node* root) {
     pthread_list_node* cursor = root;
     while(cursor != NULL) {
         pthread_join(cursor->thread, NULL);
+        pthread_list_node* prev = cursor;
         cursor = cursor->next;
-        free(cursor->previous);
+        free(prev);
     }
 }