From 42c7c3c1e6a7b6b001e7ae4f9083b29a5fb872e8 Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Tue, 15 Dec 2020 20:41:00 +0500
Subject: [PATCH] Use semaphores

---
 configure.ac      |  4 ++++
 tests/test_fork.c | 43 +++++++++++++++++++++++++++++++++++++++----
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 2e75261..7087919 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,7 @@ AC_CHECK_HEADERS([sys/mman.h])
 AC_CHECK_HEADERS([sys/stat.h])
 AC_CHECK_HEADERS([sys/types.h])
 AC_CHECK_HEADERS([sys/wait.h])
+AC_CHECK_HEADERS([time.h])
 AC_CHECK_HEADERS([unistd.h])
 
 AC_CHECK_FUNCS([close])
@@ -53,7 +54,10 @@ AC_CHECK_FUNCS([strcpy])
 AC_CHECK_FUNCS([strlen])
 AC_CHECK_FUNCS([waitpid])
 
+AC_SEARCH_LIBS([sem_getvalue], [pthread])
 AC_SEARCH_LIBS([sem_init], [pthread])
+AC_SEARCH_LIBS([sem_post], [pthread])
+AC_SEARCH_LIBS([sem_timedwait], [pthread])
 AC_SEARCH_LIBS([shm_open], [rt])
 AC_SEARCH_LIBS([shm_unlink], [rt])
 
diff --git a/tests/test_fork.c b/tests/test_fork.c
index 0d06d3e..7caea01 100644
--- a/tests/test_fork.c
+++ b/tests/test_fork.c
@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include <shmemq.h>
 
 #include <assert.h>
@@ -6,6 +8,7 @@
 #include <stdlib.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <time.h>
 #include <unistd.h>
 
 static const char name[] = "/foobar";
@@ -34,7 +37,13 @@ int main()
             const ShmemqFrame frame = shmemq_pop_start(consumer);
 
             if (frame == NULL) {
-                sleep(1);
+                struct timespec tspec;
+                const int clock_result = clock_gettime(CLOCK_REALTIME, &tspec);
+                assert(clock_result == 0);
+
+                tspec.tv_nsec += 1000;
+
+                sem_timedwait(&consumer->buffer->header.read_sem, &tspec);
                 continue;
             }
 
@@ -53,14 +62,23 @@ int main()
 
             shmemq_pop_end(consumer, &error);
             assert(error == SHMEMQ_ERROR_NONE);
+
+            int sem_value;
+            const int sem_getvalue_result =
+                sem_getvalue(&consumer->buffer->header.write_sem, &sem_value);
+            assert(sem_getvalue_result == 0);
+
+            if (sem_value == 0) {
+                const int sem_post_result =
+                    sem_post(&consumer->buffer->header.write_sem);
+                assert(sem_post_result == 0);
+            }
         }
     }
     else {
         atexit(on_exit);
         signal(SIGABRT, on_signal);
 
-        sleep(1);
-
         producer = shmemq_new(name, false, &error);
         assert(error == SHMEMQ_ERROR_NONE);
 
@@ -68,7 +86,13 @@ int main()
             const ShmemqFrame frame = shmemq_push_start(producer);
 
             if (frame == NULL) {
-                sleep(1);
+                struct timespec tspec;
+                const int clock_result = clock_gettime(CLOCK_REALTIME, &tspec);
+                assert(clock_result == 0);
+
+                tspec.tv_nsec += 1000;
+
+                sem_timedwait(&producer->buffer->header.write_sem, &tspec);
                 continue;
             }
 
@@ -84,6 +108,17 @@ int main()
 
             shmemq_push_end(producer, sizeof(unsigned), &error);
             assert(error == SHMEMQ_ERROR_NONE);
+
+            int sem_value;
+            const int sem_getvalue_result =
+                sem_getvalue(&producer->buffer->header.read_sem, &sem_value);
+            assert(sem_getvalue_result == 0);
+
+            if (sem_value == 0) {
+                const int sem_post_result =
+                    sem_post(&producer->buffer->header.read_sem);
+                assert(sem_post_result == 0);
+            }
         }
     }