importd: Avoid need for fd translation table

Make use of curl_multi_assign to associate each IO sd_event_source with
a CURL object. This means we always get passed the right event source
and don't need to worry about looking up the associated CURL object,
particularly in the case where the FD has been closed on a REMOVE event.

src/import/curl-util.c

@@ -28,13 +28,11 @@ static void curl_glue_check_finished(CurlGlue *g) {
 
 static int curl_glue_on_io(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
         CurlGlue *g = userdata;
-        int action, k = 0, translated_fd;
+        int action, k = 0;
 
         assert(s);
         assert(g);
 
-        translated_fd = PTR_TO_FD(hashmap_get(g->translate_fds, FD_TO_PTR(fd)));
-
         if (FLAGS_SET(revents, EPOLLIN | EPOLLOUT))
                 action = CURL_POLL_INOUT;
         else if (revents & EPOLLIN)
@@ -44,7 +42,7 @@ static int curl_glue_on_io(sd_event_source *s, int fd, uint32_t revents, void *u
         else
                 action = 0;
 
-        if (curl_multi_socket_action(g->curl, translated_fd, action, &k) != CURLM_OK)
+        if (curl_multi_socket_action(g->curl, fd, action, &k) != CURLM_OK)
                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
                                        "Failed to propagate IO event.");
 
@@ -53,7 +51,7 @@ static int curl_glue_on_io(sd_event_source *s, int fd, uint32_t revents, void *u
 }
 
 static int curl_glue_socket_callback(CURLM *curl, curl_socket_t s, int action, void *userdata, void *socketp) {
-        sd_event_source *io;
+        sd_event_source *io = socketp;
         CurlGlue *g = userdata;
         uint32_t events = 0;
         int r;
@@ -61,21 +59,11 @@ static int curl_glue_socket_callback(CURLM *curl, curl_socket_t s, int action, v
         assert(curl);
         assert(g);
 
-        io = hashmap_get(g->ios, FD_TO_PTR(s));
-
         if (action == CURL_POLL_REMOVE) {
                 if (io) {
-                        int fd;
-
-                        fd = sd_event_source_get_io_fd(io);
-                        assert(fd >= 0);
-
                         sd_event_source_disable_unref(io);
 
                         hashmap_remove(g->ios, FD_TO_PTR(s));
-                        hashmap_remove(g->translate_fds, FD_TO_PTR(fd));
-
-                        safe_close(fd);
                 }
 
                 return 0;
@@ -87,12 +75,6 @@ static int curl_glue_socket_callback(CURLM *curl, curl_socket_t s, int action, v
                 return -1;
         }
 
-        r = hashmap_ensure_allocated(&g->translate_fds, &trivial_hash_ops);
-        if (r < 0) {
-                log_oom();
-                return -1;
-        }
-
         if (action == CURL_POLL_IN)
                 events = EPOLLIN;
         else if (action == CURL_POLL_OUT)
@@ -107,19 +89,10 @@ static int curl_glue_socket_callback(CURLM *curl, curl_socket_t s, int action, v
                 if (sd_event_source_set_enabled(io, SD_EVENT_ON) < 0)
                         return -1;
         } else {
-                _cleanup_close_ int fd = -1;
+                if (sd_event_add_io(g->event, &io, s, events, curl_glue_on_io, g) < 0)
-
-                /* When curl needs to remove an fd from us it closes
-                 * the fd first, and only then calls into us. This is
-                 * nasty, since we cannot pass the fd on to epoll()
-                 * anymore. Hence, duplicate the fds here, and keep a
-                 * copy for epoll which we control after use. */
-
-                fd = fcntl(s, F_DUPFD_CLOEXEC, 3);
-                if (fd < 0)
                         return -1;
 
-                if (sd_event_add_io(g->event, &io, fd, events, curl_glue_on_io, g) < 0)
+                if (curl_multi_assign(g->curl, s, io) != CURLM_OK)
                         return -1;
 
                 (void) sd_event_source_set_description(io, "curl-io");
@@ -130,16 +103,6 @@ static int curl_glue_socket_callback(CURLM *curl, curl_socket_t s, int action, v
                         sd_event_source_unref(io);
                         return -1;
                 }
-
-                r = hashmap_put(g->translate_fds, FD_TO_PTR(fd), FD_TO_PTR(s));
-                if (r < 0) {
-                        log_oom();
-                        hashmap_remove(g->ios, FD_TO_PTR(s));
-                        sd_event_source_unref(io);
-                        return -1;
-                }
-
-                fd = -1;
         }
 
         return 0;
@@ -204,14 +167,6 @@ CurlGlue *curl_glue_unref(CurlGlue *g) {
                 curl_multi_cleanup(g->curl);
 
         while ((io = hashmap_steal_first(g->ios))) {
-                int fd;
-
-                fd = sd_event_source_get_io_fd(io);
-                assert(fd >= 0);
-
-                hashmap_remove(g->translate_fds, FD_TO_PTR(fd));
-
-                safe_close(fd);
                 sd_event_source_unref(io);
         }
 

src/import/curl-util.h

@@ -16,7 +16,6 @@ struct CurlGlue {
         CURLM *curl;
         sd_event_source *timer;
         Hashmap *ios;
-        Hashmap *translate_fds;
 
         void (*on_finished)(CurlGlue *g, CURL *curl, CURLcode code);
         void *userdata;