Fix: prioritize control socket communication in relayd

[lttng-tools.git] / src / common / compat / poll.h

diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index 46200ac3e313effea9c198ef0dd061008341133e..49673cd5af643e40a10aa9173d1ff4cf489d0802 100644 (file)
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -18,6 +18,7 @@
 #ifndef _LTT_POLL_H
 #define _LTT_POLL_H
 
+#include <assert.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -42,7 +43,9 @@ extern unsigned int poll_max_size;
  */
 static inline void __lttng_poll_free(void *events)
 {
-       free(events);
+       if (events) {
+               free(events);
+       }
 }
 
 /*
@@ -76,11 +79,25 @@ enum {
 struct compat_epoll_event {
        int epfd;
        uint32_t nb_fd;       /* Current number of fd in events */
-       uint32_t events_size; /* Size of events array */
+       uint32_t alloc_size; /* Size of events array */
+       uint32_t init_size;     /* Initial size of events array */
        struct epoll_event *events;
 };
 #define lttng_poll_event compat_epoll_event
 
+static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
+               int index, uint32_t nb_fd)
+{
+       assert(events);
+       assert(index != nb_fd);
+
+       if (index == 0 || nb_fd == 0) {
+               return -1;
+       } else {
+               return events->events[index - 1].data.fd;
+       }
+}
+
 /*
  * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
  * being the index of the events array.
@@ -89,6 +106,8 @@ struct compat_epoll_event {
 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
 #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
+#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
+       __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
 
 /*
  * Create the epoll set. No memory allocation is done here.
@@ -188,7 +207,7 @@ enum {
 #if __linux__
        LPOLLMSG = POLLMSG,
        LPOLLRDHUP = POLLRDHUP,
-#elif defined(__FreeBSD__)
+#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
        LPOLLMSG = 0,
        LPOLLRDHUP = 0,
 #else
@@ -200,21 +219,55 @@ enum {
        LTTNG_CLOEXEC = 0xdead,
 };
 
-struct compat_poll_event {
+struct compat_poll_event_array {
        uint32_t nb_fd;       /* Current number of fd in events */
-       uint32_t events_size; /* Size of events array */
+       uint32_t alloc_size; /* Size of events array */
+       /* Initial size of the pollset. We never shrink below that. */
+       uint32_t init_size;
        struct pollfd *events;
 };
+
+struct compat_poll_event {
+       /*
+        * Modified by the wait action. Updated using current fields if the
+        * need_update flag is set.
+        */
+       struct compat_poll_event_array wait;
+       /*
+        * This is modified by add/del actions being the _current_ flow of
+        * execution before a poll wait is done.
+        */
+       struct compat_poll_event_array current;
+       /* Indicate if wait.events needs to be realloc. */
+       int need_realloc:1;
+       /* Indicate if wait.events need to be updated from current. */
+       int need_update:1;
+};
 #define lttng_poll_event compat_poll_event
 
+static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
+               int index, uint32_t nb_fd)
+{
+       assert(events);
+       assert(index != nb_fd);
+
+       if (index == 0 || nb_fd == 0) {
+               return -1;
+       } else {
+               return events->current.events[index - 1].fd;
+       }
+}
+
 /*
  * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
  * being the index of the events array.
  */
-#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].fd
-#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].revents
-#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
-#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
+#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
+#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
+#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
+#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
+#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
+       __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
 
 /*
  * Create a pollfd structure of size 'size'.
@@ -268,7 +321,8 @@ static inline void lttng_poll_reset(struct lttng_poll_event *events)
 static inline void lttng_poll_clean(struct lttng_poll_event *events)
 {
        if (events) {
-               __lttng_poll_free((void *) events->events);
+               __lttng_poll_free((void *) events->wait.events);
+               __lttng_poll_free((void *) events->current.events);
        }
 }