fix: reopen FIFO on EOF to prevent blocking on subsequent writes

Co-authored-by: aider (deepseek/deepseek-reasoner) <aider@aider.chat>

src/pipe.c

@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
@@ -19,58 +20,67 @@ extern spsc_queue_t cmd_queue_main_fifo;
 
 static void *pipe_thread_func(void *arg) {
   (void)arg;
-  FILE *fifo = fopen(FIFO_PATH, "r");
-  if (!fifo) {
-    perror("fopen fifo");
-    return NULL;
-  }
   char line[LINE_MAX];
-  while (fgets(line, sizeof(line), fifo)) {
-    /* strip newline */
-    size_t len = strlen(line);
-    if (len > 0 && line[len - 1] == '\n')
-      line[len - 1] = '\0';
 
-    if (strcmp(line, "add") == 0) {
+  while (1) {
-      command_t cmd = {.type = CMD_ADD_CHANNEL, .channel = -1, .data = 0};
+    FILE *fifo = fopen(FIFO_PATH, "r");
-      queue_push(&cmd_queue_main_fifo, cmd);
+    if (!fifo) {
-    } else if (strcmp(line, "add_midi") == 0) {
+      perror("fopen fifo");
-      command_t cmd = {.type = CMD_ADD_MIDI_CHANNEL, .channel = -1, .data = 0};
+      return NULL;
-      queue_push(&cmd_queue_main_fifo, cmd);
-    } else if (strcmp(line, "remove") == 0) {
-      command_t cmd = {.type = CMD_REMOVE_CHANNEL, .channel = -1, .data = 0};
-      queue_push(&cmd_queue_main_fifo, cmd);
-    } else if (strncmp(line, "record ", 7) == 0) {
-      int ch = atoi(line + 7);
-      command_t cmd = {.type = CMD_CYCLE, .channel = ch, .data = 0};
-      queue_push(&cmd_queue, cmd);
-    } else if (strcmp(line, "stop") == 0) {
-      command_t cmd = {.type = CMD_STOP, .channel = -1, .data = 0};
-      queue_push(&cmd_queue, cmd);
-    } else if (strncmp(line, "bind ", 5) == 0) {
-      int ch = atoi(line + 5);
-      command_t cmd = {.type = CMD_BIND_CHANNEL, .channel = -1, .data = ch};
-      queue_push(&cmd_queue, cmd);
-    } else if (strcmp(line, "unbind") == 0) {
-      command_t cmd = {.type = CMD_UNBIND, .channel = -1, .data = 0};
-      queue_push(&cmd_queue, cmd);
-    } else if (strcmp(line, "scene_add") == 0) {
-      command_t cmd = {.type = CMD_ADD_SCENE, .channel = -1, .data = 0};
-      queue_push(&cmd_queue_main_fifo, cmd);
-    } else if (strcmp(line, "scene_remove") == 0) {
-      command_t cmd = {.type = CMD_REMOVE_SCENE, .channel = -1, .data = 0};
-      queue_push(&cmd_queue_main_fifo, cmd);
-    } else if (strcmp(line, "scene_next") == 0) {
-      command_t cmd = {.type = CMD_NEXT_SCENE, .channel = -1, .data = 0};
-      queue_push(&cmd_queue_main_fifo, cmd);
-    } else if (strcmp(line, "scene_prev") == 0) {
-      command_t cmd = {.type = CMD_PREV_SCENE, .channel = -1, .data = 0};
-      queue_push(&cmd_queue_main_fifo, cmd);
     }
-    /* ignore unknown lines */
+
+    while (fgets(line, sizeof(line), fifo)) {
+      /* strip newline */
+      size_t len = strlen(line);
+      if (len > 0 && line[len - 1] == '\n')
+        line[len - 1] = '\0';
+
+      if (strcmp(line, "add") == 0) {
+        command_t cmd = {.type = CMD_ADD_CHANNEL, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strcmp(line, "add_midi") == 0) {
+        command_t cmd = {.type = CMD_ADD_MIDI_CHANNEL, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strcmp(line, "remove") == 0) {
+        command_t cmd = {.type = CMD_REMOVE_CHANNEL, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strncmp(line, "record ", 7) == 0) {
+        int ch = atoi(line + 7);
+        command_t cmd = {.type = CMD_CYCLE, .channel = ch, .data = 0};
+        queue_push(&cmd_queue, cmd);
+      } else if (strcmp(line, "stop") == 0) {
+        command_t cmd = {.type = CMD_STOP, .channel = -1, .data = 0};
+        queue_push(&cmd_queue, cmd);
+      } else if (strncmp(line, "bind ", 5) == 0) {
+        int ch = atoi(line + 5);
+        command_t cmd = {.type = CMD_BIND_CHANNEL, .channel = -1, .data = ch};
+        queue_push(&cmd_queue, cmd);
+      } else if (strcmp(line, "unbind") == 0) {
+        command_t cmd = {.type = CMD_UNBIND, .channel = -1, .data = 0};
+        queue_push(&cmd_queue, cmd);
+      } else if (strcmp(line, "scene_add") == 0) {
+        command_t cmd = {.type = CMD_ADD_SCENE, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strcmp(line, "scene_remove") == 0) {
+        command_t cmd = {.type = CMD_REMOVE_SCENE, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strcmp(line, "scene_next") == 0) {
+        command_t cmd = {.type = CMD_NEXT_SCENE, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      } else if (strcmp(line, "scene_prev") == 0) {
+        command_t cmd = {.type = CMD_PREV_SCENE, .channel = -1, .data = 0};
+        queue_push(&cmd_queue_main_fifo, cmd);
+      }
+      /* ignore unknown lines */
+    }
+    /* EOF – all writers closed, reopen for next connection */
+    fclose(fifo);
+    {
+      struct timespec ts = {.tv_sec = 0, .tv_nsec = 50000000};
+      nanosleep(&ts, NULL);
+    } /* small pause before retrying */
   }
-  fclose(fifo);
+  return NULL; /* unreachable */
-  return NULL;
 }
 
 int pipe_start_reader(void) {