fix: use send instead of write to prevent SIGPIPE

example/blocking.c

@@ -34,5 +34,5 @@ int main() {
   lnm_log_init_global();
   lnm_log_register_stdout(lnm_log_level_debug);
 
-  lnm_http_loop_run(hl, 8080, 1);
+  printf("res = %i\n", lnm_http_loop_run(hl, 8080, 1, 32));
 }

include/lnm/http/loop.h

@@ -81,7 +81,8 @@ lnm_err lnm_http_route_init_regex(lnm_http_route **out, lnm_http_method method,
  */
 lnm_err lnm_http_loop_route_add(lnm_http_loop *hl, lnm_http_route *route);
 
-lnm_err lnm_http_loop_run(lnm_http_loop *hl, uint16_t port, int thread_count);
+lnm_err lnm_http_loop_run(lnm_http_loop *hl, uint16_t port,
+                          size_t epoll_threads, size_t worker_threads);
 
 void lnm_http_loop_set_api_key(lnm_http_loop *hl, const char *api_key);
 

include/lnm/loop.h

@@ -9,6 +9,7 @@
 #include "lnm/common.h"
 
 #define LNM_LOOP_BUF_SIZE 2048
+#define LNM_QUEUE_MULTIPLIER 8
 
 typedef enum lnm_loop_state {
   lnm_loop_state_req = 0,
@@ -46,6 +47,7 @@ typedef struct lnm_loop_queue {
   } buf;
   size_t head;
   size_t tail;
+  bool empty;
   pthread_mutex_t mutex;
   pthread_cond_t cond;
 } lnm_loop_queue;
@@ -77,6 +79,12 @@ typedef struct lnm_loop {
   void (*data_read)(lnm_loop_conn *conn);
   void (*data_write)(lnm_loop_conn *conn);
   lnm_loop_queue *wq;
+  struct {
+    // Mutex shared between all threads; used for counting thread IDs
+    pthread_mutex_t mutex;
+    size_t worker_count;
+    size_t epoll_count;
+  } threads;
 } lnm_loop;
 
 lnm_err lnm_loop_init(lnm_loop **out, void *gctx,
@@ -87,7 +95,16 @@ lnm_err lnm_loop_init(lnm_loop **out, void *gctx,
 
 lnm_err lnm_loop_setup(lnm_loop *l, uint16_t port);
 
-lnm_err lnm_loop_run(lnm_loop *l, int thread_count);
+/**
+ * Run a single epoll thread of the event loop.
+ */
+lnm_err lnm_loop_run(lnm_loop *l);
+
+/**
+ * Run a multithreaded event loop with the configured number of threads.
+ */
+lnm_err lnm_loop_run_multi(lnm_loop *l, size_t epoll_threads,
+                           size_t worker_threads);
 
 /**
  * Reschedule the given connection, either on the event loop for network IO or

src/_include/lnm/http/loop_internal.h

@@ -8,6 +8,7 @@
 typedef struct lnm_http_step {
   lnm_http_step_fn fn;
   struct lnm_http_step *next;
+  bool blocking;
 } lnm_http_step;
 
 typedef enum lnm_http_route_type {

src/http/lnm_http_loop.c

@@ -122,9 +122,10 @@ lnm_err lnm_http_loop_route_add(lnm_http_loop *hl, lnm_http_route *route) {
   return lnm_err_ok;
 }
 
-lnm_err lnm_http_loop_run(lnm_http_loop *hl, uint16_t port, int thread_count) {
+lnm_err lnm_http_loop_run(lnm_http_loop *hl, uint16_t port,
+                          size_t epoll_threads, size_t worker_threads) {
   LNM_RES(lnm_loop_setup(hl, port));
-  return lnm_loop_run(hl, thread_count);
+  return lnm_loop_run_multi(hl, epoll_threads, worker_threads);
 }
 
 void lnm_http_loop_set_api_key(lnm_http_loop *hl, const char *api_key) {

src/http/lnm_http_loop_process.c

@@ -133,11 +133,19 @@ void lnm_http_loop_process_steps(lnm_http_conn *conn) {
   while ((ctx->cur_step != NULL) && (step != ctx->cur_step)) {
     step = ctx->cur_step;
 
+    if (step->blocking && (conn->state != lnm_loop_state_req_blocking)) {
+      conn->state = lnm_loop_state_req_blocking;
+
+      break;
+    }
+
     switch (step->fn(conn)) {
     case lnm_http_step_err_done:
       ctx->cur_step = ctx->cur_step->next;
       break;
     case lnm_http_step_err_io_needed:
+      // Ensure steps that require more I/O are executed on the event loop
+      conn->state = lnm_loop_state_req;
       break;
     case lnm_http_step_err_close:
       conn->state = lnm_loop_state_end;
@@ -149,6 +157,7 @@ void lnm_http_loop_process_steps(lnm_http_conn *conn) {
   }
 
   if (ctx->cur_step == NULL) {
+    conn->state = lnm_loop_state_res;
     ctx->state = lnm_http_loop_state_add_headers;
   }
 }

src/loop/lnm_loop.c

@@ -30,6 +30,8 @@ lnm_err lnm_loop_init(lnm_loop **out, void *gctx,
   l->data_read = data_read;
   l->data_write = data_write;
 
+  pthread_mutex_init(&l->threads.mutex, NULL);
+
   *out = l;
 
   return lnm_err_ok;
@@ -157,19 +159,21 @@ void lnm_loop_conn_schedule(lnm_loop *l, lnm_loop_conn *conn) {
   }
 }
 
-typedef struct lnm_loop_thread_args {
-  lnm_loop *l;
-  int id;
-  int thread_count;
-} lnm_loop_thread_args;
+lnm_err lnm_loop_run(lnm_loop *l) {
+  if (l->epoll_fd == 0) {
+    return lnm_err_not_setup;
+  }
 
-lnm_err lnm_loop_run_thread(lnm_loop_thread_args *args) {
-  lnm_loop *l = args->l;
-  int thread_id = args->id;
-  int thread_count = args->thread_count;
+  // Get thread ID by incrementing counter
+  pthread_mutex_lock(&l->threads.mutex);
+
+  int thread_id = l->threads.epoll_count;
+  l->threads.epoll_count++;
+
+  pthread_mutex_unlock(&l->threads.mutex);
 
   struct epoll_event *events = calloc(1, sizeof(struct epoll_event));
-  int events_cap = 1;
+  size_t events_cap = 1;
 
   if (events == NULL) {
     return lnm_err_failed_alloc;
@@ -197,9 +201,10 @@ lnm_err lnm_loop_run_thread(lnm_loop_thread_args *args) {
       }
     }
 
-    int open = l->open;
-    int cap_per_thread =
-        open + 1 > thread_count ? (open + 1) / thread_count : 1;
+    size_t open = l->open;
+    size_t cap_per_thread = open + 1 > l->threads.epoll_count
+                                ? (open + 1) / l->threads.epoll_count
+                                : 1;
 
     if (cap_per_thread > events_cap) {
       struct epoll_event *new_events =
@@ -218,28 +223,21 @@ lnm_err lnm_loop_run_thread(lnm_loop_thread_args *args) {
   return lnm_err_ok;
 }
 
-lnm_err lnm_loop_run(lnm_loop *l, int thread_count) {
-  if (l->epoll_fd == 0) {
-    return lnm_err_not_setup;
+lnm_err lnm_loop_run_multi(lnm_loop *l, size_t epoll_threads,
+                           size_t worker_threads) {
+  if (worker_threads > 0) {
+    LNM_RES(lnm_loop_queue_init(&l->wq, LNM_QUEUE_MULTIPLIER * worker_threads));
   }
 
-  lnm_loop_thread_args args[thread_count];
+  pthread_t t;
 
-  for (int i = 1; i < thread_count; i++) {
-    args[i].l = l;
-    args[i].id = i;
-    args[i].thread_count = thread_count;
-
-    pthread_t thread;
-    pthread_create(&thread, NULL, (void *(*)(void *))lnm_loop_run_thread,
-                   &args[i]);
+  for (size_t i = 1; i < epoll_threads; i++) {
+    pthread_create(&t, NULL, (void *(*)(void *))lnm_loop_run, l);
   }
 
-  args[0].l = l;
-  args[0].id = 0;
-  args[0].thread_count = thread_count;
-
-  lnm_loop_run_thread(&args[0]);
-
-  return lnm_err_ok;
+  for (size_t i = 0; i < worker_threads; i++) {
+    pthread_create(&t, NULL, (void *(*)(void *))lnm_loop_worker_run, l);
+  }
+
+  return lnm_loop_run(l);
 }

src/loop/lnm_loop_io.c

@@ -1,6 +1,7 @@
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/socket.h>
 
 #include "lnm/loop.h"
 #include "lnm/loop_internal.h"
@@ -43,7 +44,9 @@ void lnm_loop_conn_io_res(lnm_loop *l, lnm_loop_conn *conn) {
     ssize_t res;
 
     do {
-      res = write(conn->fd, conn->w.buf, conn->w.size);
+      // Send with MSG_NOSIGNAL prevents closed pipes from exiting the program
+      // with SIGPIPE
+      res = send(conn->fd, conn->w.buf, conn->w.size, MSG_NOSIGNAL);
     } while (res < 0 && errno == EINTR);
 
     // Write can't be performed without blocking; we come back later

src/loop/lnm_loop_worker.c

@@ -1,9 +1,10 @@
 #include <sys/epoll.h>
 
+#include "lnm/log.h"
 #include "lnm/loop.h"
 
 lnm_err lnm_loop_queue_init(lnm_loop_queue **out, size_t cap) {
-  lnm_loop_conn **arr = malloc(cap * sizeof(lnm_loop_conn *));
+  lnm_loop_conn **arr = calloc(cap, sizeof(lnm_loop_conn *));
 
   if (arr == NULL) {
     return lnm_err_failed_alloc;
@@ -20,6 +21,10 @@ lnm_err lnm_loop_queue_init(lnm_loop_queue **out, size_t cap) {
   q->buf.arr = arr;
   q->buf.len = cap;
 
+  q->tail = 0;
+  q->head = 0;
+  q->empty = true;
+
   pthread_mutex_init(&q->mutex, NULL);
   pthread_cond_init(&q->cond, NULL);
 
@@ -31,14 +36,15 @@ lnm_err lnm_loop_queue_init(lnm_loop_queue **out, size_t cap) {
 void lnm_loop_queue_push(lnm_loop_queue *q, lnm_loop_conn *conn) {
   pthread_mutex_lock(&q->mutex);
 
-  while (q->tail == q->head) {
+  while (q->head == q->tail && !q->empty) {
     pthread_cond_wait(&q->cond, &q->mutex);
   }
 
-  q->buf.arr[q->tail] = conn;
+  q->buf.arr[q->head] = conn;
 
   // Make sure the index wraps around
-  q->tail = (q->tail + 1) % q->buf.len;
+  q->head = (q->head + 1) % q->buf.len;
+  q->empty = false;
 
   // Unlock mutex and signal to waiting threads
   pthread_mutex_unlock(&q->mutex);
@@ -48,12 +54,14 @@ void lnm_loop_queue_push(lnm_loop_queue *q, lnm_loop_conn *conn) {
 lnm_loop_conn *lnm_loop_queue_pop(lnm_loop_queue *q) {
   pthread_mutex_lock(&q->mutex);
 
-  while (q->tail == q->head) {
+  while (q->empty) {
     pthread_cond_wait(&q->cond, &q->mutex);
   }
 
-  lnm_loop_conn *out = q->buf.arr[q->head];
-  q->head = (q->head + 1) % q->buf.len;
+  lnm_loop_conn *out = q->buf.arr[q->tail];
+
+  q->tail = (q->tail + 1) % q->buf.len;
+  q->empty = q->tail == q->head;
 
   // Unlock mutex and signal to waiting threads
   pthread_mutex_unlock(&q->mutex);
@@ -66,8 +74,17 @@ void lnm_loop_worker_run(void *arg) {
   lnm_loop *l = arg;
   lnm_loop_queue *q = l->wq;
 
+  // Get thread ID by incrementing counter
+  pthread_mutex_lock(&l->threads.mutex);
+
+  int thread_id = l->threads.worker_count;
+  l->threads.worker_count++;
+
+  pthread_mutex_unlock(&l->threads.mutex);
+
   while (1) {
     lnm_loop_conn *conn = lnm_loop_queue_pop(q);
+    lnm_ldebug("loop", "worker %i processing fd %i", thread_id, conn->fd);
 
     switch (conn->state) {
     case lnm_loop_state_req_blocking: