Test a little more of compat_threads.c

src/common/compat_threads.c

@@ -155,19 +155,18 @@ sock_drain(tor_socket_t fd)
 /** Allocate a new set of alert sockets, and set the appropriate function
  * pointers, in <b>socks_out</b>. */
 int
-alert_sockets_create(alert_sockets_t *socks_out)
+alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags)
 {
-  tor_socket_t socks[2];
+  tor_socket_t socks[2] = { TOR_INVALID_SOCKET, TOR_INVALID_SOCKET };
 
 #ifdef HAVE_EVENTFD
   /* First, we try the Linux eventfd() syscall.  This gives a 64-bit counter
    * associated with a single file descriptor. */
 #if defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
-  socks[0] = eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK);
+  if (!(flags & ASOCKS_NOEVENTFD2))
-#else
+    socks[0] = eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK);
-  socks[0] = -1;
 #endif
-  if (socks[0] < 0) {
+  if (socks[0] < 0 && !(flags & ASOCKS_NOEVENTFD)) {
     socks[0] = eventfd(0,0);
     if (socks[0] >= 0) {
       if (fcntl(socks[0], F_SETFD, FD_CLOEXEC) < 0 ||
@@ -188,7 +187,8 @@ alert_sockets_create(alert_sockets_t *socks_out)
 #ifdef HAVE_PIPE2
   /* Now we're going to try pipes. First type the pipe2() syscall, if we
    * have it, so we can save some calls... */
-  if (pipe2(socks, O_NONBLOCK|O_CLOEXEC) == 0) {
+  if (!(flags & ASOCKS_NOPIPE2) &&
+      pipe2(socks, O_NONBLOCK|O_CLOEXEC) == 0) {
     socks_out->read_fd = socks[0];
     socks_out->write_fd = socks[1];
     socks_out->alert_fn = pipe_alert;
@@ -200,7 +200,8 @@ alert_sockets_create(alert_sockets_t *socks_out)
 #ifdef HAVE_PIPE
   /* Now try the regular pipe() syscall.  Pipes have a bit lower overhead than
    * socketpairs, fwict. */
-  if (pipe(socks) == 0) {
+  if (!(flags & ASOCKS_NOPIPE) &&
+      pipe(socks) == 0) {
     if (fcntl(socks[0], F_SETFD, FD_CLOEXEC) < 0 ||
         fcntl(socks[1], F_SETFD, FD_CLOEXEC) < 0 ||
         set_socket_nonblocking(socks[0]) < 0 ||
@@ -218,7 +219,8 @@ alert_sockets_create(alert_sockets_t *socks_out)
 #endif
 
   /* If nothing else worked, fall back on socketpair(). */
-  if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, socks) == 0) {
+  if (!(flags & ASOCKS_NOSOCKETPAIR) &&
+      tor_socketpair(AF_UNIX, SOCK_STREAM, 0, socks) == 0) {
     if (set_socket_nonblocking(socks[0]) < 0 ||
         set_socket_nonblocking(socks[1])) {
       tor_close_socket(socks[0]);

src/common/compat_threads.h

@@ -102,7 +102,14 @@ typedef struct alert_sockets_s {
   int (*drain_fn)(tor_socket_t read_fd);
 } alert_sockets_t;
 
-int alert_sockets_create(alert_sockets_t *socks_out);
+/* Flags to disable one or more alert_sockets backends. */
+#define ASOCKS_NOEVENTFD2   (1u<<0)
+#define ASOCKS_NOEVENTFD    (1u<<1)
+#define ASOCKS_NOPIPE2      (1u<<2)
+#define ASOCKS_NOPIPE       (1u<<3)
+#define ASOCKS_NOSOCKETPAIR (1u<<4)
+
+int alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags);
 void alert_sockets_close(alert_sockets_t *socks);
 
 #endif

src/common/workqueue.c

@@ -397,12 +397,12 @@ threadpool_get_replyqueue(threadpool_t *tp)
  * IO-centric event loop, it needs to get woken up with means other than a
  * condition variable. */
 replyqueue_t *
-replyqueue_new(void)
+replyqueue_new(uint32_t alertsocks_flags)
 {
   replyqueue_t *rq;
 
   rq = tor_malloc_zero(sizeof(replyqueue_t));
-  if (alert_sockets_create(&rq->alert) < 0) {
+  if (alert_sockets_create(&rq->alert, alertsocks_flags) < 0) {
     tor_free(rq);
     return NULL;
   }

src/common/workqueue.h

@@ -40,7 +40,7 @@ threadpool_t *threadpool_new(int n_threads,
                              void *arg);
 replyqueue_t *threadpool_get_replyqueue(threadpool_t *tp);
 
-replyqueue_t *replyqueue_new(void);
+replyqueue_t *replyqueue_new(uint32_t alertsocks_flags);
 tor_socket_t replyqueue_get_socket(replyqueue_t *rq);
 void replyqueue_process(replyqueue_t *queue);
 

src/test/test_workqueue.c

@@ -249,8 +249,10 @@ help(void)
      "    -N <items>    Run this many items of work\n"
      "    -T <threads>  Use this many threads\n"
      "    -I <inflight> Have no more than this many requests queued at once\n"
-     "    -L <lowwater> Add items whenever fewer than this many are pending.\n"
+     "    -L <lowwater> Add items whenever fewer than this many are pending\n"
-     "    -R <ratio>    Make one out of this many items be a slow (RSA) one");
+     "    -R <ratio>    Make one out of this many items be a slow (RSA) one\n"
+     "    --no-{eventfd2,eventfd,pipe2,pipe,socketpair}\n"
+     "                  Disable one of the alert_socket backends.");
 }
 
 int
@@ -261,6 +263,7 @@ main(int argc, char **argv)
   int i;
   tor_libevent_cfg evcfg;
   struct event *ev;
+  uint32_t as_flags = 0;
 
   for (i = 1; i < argc; ++i) {
     if (!strcmp(argv[i], "-v")) {
@@ -275,6 +278,16 @@ main(int argc, char **argv)
       opt_n_lowwater = atoi(argv[++i]);
     } else if (!strcmp(argv[i], "-R") && i+1<argc) {
       opt_ratio_rsa = atoi(argv[++i]);
+    } else if (!strcmp(argv[i], "--no-eventfd2")) {
+      as_flags |= ASOCKS_NOEVENTFD2;
+    } else if (!strcmp(argv[i], "--no-eventfd")) {
+      as_flags |= ASOCKS_NOEVENTFD;
+    } else if (!strcmp(argv[i], "--no-pipe2")) {
+      as_flags |= ASOCKS_NOPIPE2;
+    } else if (!strcmp(argv[i], "--no-pipe")) {
+      as_flags |= ASOCKS_NOPIPE;
+    } else if (!strcmp(argv[i], "--no-socketpair")) {
+      as_flags |= ASOCKS_NOSOCKETPAIR;
     } else if (!strcmp(argv[i], "-h")) {
       help();
       return 0;
@@ -294,7 +307,7 @@ main(int argc, char **argv)
   crypto_global_init(1, NULL, NULL);
   crypto_seed_rng(1);
 
-  rq = replyqueue_new();
+  rq = replyqueue_new(as_flags);
   tor_assert(rq);
   tp = threadpool_new(opt_n_threads,
                       rq, new_state, free_state, NULL);