ext/libuv/src/unix/os390-syscalls.c in libuv-4.0.0 vs ext/libuv/src/unix/os390-syscalls.c in libuv-4.0.1

@@ -23,10 +23,12 @@
 #include "os390-syscalls.h"
 #include <errno.h>
 #include <stdlib.h>
 #include <assert.h>
 #include <search.h>
+#include <termios.h>
+#include <sys/msg.h>
 
 #define CW_CONDVAR 32
 
 #pragma linkage(BPX4CTW, OS)
 #pragma linkage(BPX1CTW, OS)
@@ -101,27 +103,65 @@
 
 static void maybe_resize(uv__os390_epoll* lst, unsigned int len) {
   unsigned int newsize;
   unsigned int i;
   struct pollfd* newlst;
+  struct pollfd event;
 
   if (len <= lst->size)
     return;
 
+  if (lst->size == 0)
+    event.fd = -1;
+  else {
+    /* Extract the message queue at the end. */
+    event = lst->items[lst->size - 1];
+    lst->items[lst->size - 1].fd = -1;
+  }
+
   newsize = next_power_of_two(len);
   newlst = uv__realloc(lst->items, newsize * sizeof(lst->items[0]));
 
   if (newlst == NULL)
     abort();
   for (i = lst->size; i < newsize; ++i)
     newlst[i].fd = -1;
 
+  /* Restore the message queue at the end */
+  newlst[newsize - 1] = event;
+
   lst->items = newlst;
   lst->size = newsize;
 }
 
 
+static void init_message_queue(uv__os390_epoll* lst) {
+  struct {
+    long int header;
+    char body;
+  } msg;
+
+  /* initialize message queue */
+  lst->msg_queue = msgget(IPC_PRIVATE, 0622 | IPC_CREAT);
+  if (lst->msg_queue == -1)
+    abort();
+
+  /*
+     On z/OS, the message queue will be affiliated with the process only
+     when a send is performed on it. Once this is done, the system
+     can be queried for all message queues belonging to our process id.
+  */
+  msg.header = 1;
+  if (msgsnd(lst->msg_queue, &msg, sizeof(msg.body), 0) != 0)
+    abort();
+
+  /* Clean up the dummy message sent above */
+  if (msgrcv(lst->msg_queue, &msg, sizeof(msg.body), 0, 0) != sizeof(msg.body))
+    abort();
+}
+
+
 static void before_fork(void) {
   uv_mutex_lock(&global_epoll_lock);
 }
 
 
@@ -137,12 +177,17 @@
   /* reset once */
   memcpy(&once, &child_once, sizeof(child_once));
 
   /* reset epoll list */
   while (!QUEUE_EMPTY(&global_epoll_queue)) {
+    uv__os390_epoll* lst;
     q = QUEUE_HEAD(&global_epoll_queue);
     QUEUE_REMOVE(q);
+    lst = QUEUE_DATA(q, uv__os390_epoll, member);
+    uv__free(lst->items);
+    lst->items = NULL;
+    lst->size = 0;
   }
 
   uv_mutex_unlock(&global_epoll_lock);
   uv_mutex_destroy(&global_epoll_lock);
 }
@@ -164,10 +209,15 @@
   lst = uv__malloc(sizeof(*lst));
   if (lst != NULL) {
     /* initialize list */
     lst->size = 0;
     lst->items = NULL;
+    init_message_queue(lst);
+    maybe_resize(lst, 1);
+    lst->items[lst->size - 1].fd = lst->msg_queue;
+    lst->items[lst->size - 1].events = POLLIN;
+    lst->items[lst->size - 1].revents = 0;
     uv_once(&once, epoll_init);
     uv_mutex_lock(&global_epoll_lock);
     QUEUE_INSERT_TAIL(&global_epoll_queue, &lst->member);
     uv_mutex_unlock(&global_epoll_lock);
   }
@@ -180,27 +230,33 @@
               int op,
               int fd,
               struct epoll_event *event) {
   uv_mutex_lock(&global_epoll_lock);
 
-  if(op == EPOLL_CTL_DEL) {
+  if (op == EPOLL_CTL_DEL) {
     if (fd >= lst->size || lst->items[fd].fd == -1) {
       uv_mutex_unlock(&global_epoll_lock);
       errno = ENOENT;
       return -1;
     }
     lst->items[fd].fd = -1;
-  } else if(op == EPOLL_CTL_ADD) {
-    maybe_resize(lst, fd + 1);
+  } else if (op == EPOLL_CTL_ADD) {
+
+    /* Resizing to 'fd + 1' would expand the list to contain at least
+     * 'fd'. But we need to guarantee that the last index on the list 
+     * is reserved for the message queue. So specify 'fd + 2' instead.
+     */
+    maybe_resize(lst, fd + 2);
     if (lst->items[fd].fd != -1) {
       uv_mutex_unlock(&global_epoll_lock);
       errno = EEXIST;
       return -1;
     }
     lst->items[fd].fd = fd;
     lst->items[fd].events = event->events;
-  } else if(op == EPOLL_CTL_MOD) {
+    lst->items[fd].revents = 0;
+  } else if (op == EPOLL_CTL_MOD) {
     if (fd >= lst->size || lst->items[fd].fd == -1) {
       uv_mutex_unlock(&global_epoll_lock);
       errno = ENOENT;
       return -1;
     }
@@ -213,21 +269,23 @@
 }
 
 
 int epoll_wait(uv__os390_epoll* lst, struct epoll_event* events,
                int maxevents, int timeout) {
-  size_t size;
+  nmsgsfds_t size;
   struct pollfd* pfds;
   int pollret;
   int reventcount;
 
-  size = lst->size;
+  size = _SET_FDS_MSGS(size, 1, lst->size - 1);
   pfds = lst->items;
   pollret = poll(pfds, size, timeout);
   if (pollret <= 0)
     return pollret;
 
+  pollret = _NFDS(pollret) + _NMSGS(pollret);
+
   reventcount = 0;
   for (int i = 0; 
        i < lst->size && i < maxevents && reventcount < pollret; ++i) {
     struct epoll_event ev;
 
@@ -259,12 +317,17 @@
   uv_mutex_unlock(&global_epoll_lock);
   return 0;
 }
 
 void epoll_queue_close(uv__os390_epoll* lst) {
+  /* Remove epoll instance from global queue */
   uv_mutex_lock(&global_epoll_lock);
   QUEUE_REMOVE(&lst->member);
   uv_mutex_unlock(&global_epoll_lock);
+
+  /* Free resources */
+  msgctl(lst->msg_queue, IPC_RMID, NULL);
+  lst->msg_queue = -1;
   uv__free(lst->items);
   lst->items = NULL;
 }