test: Add test-rnd-from-file test

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

test/Makefile

 SRCS	+= test-counter.c
+SRCS	+= test-rnd-from-file.c
 
 OBJS	:= $(patsubst %.c,%.o,$(SRCS))
 PROGS	:= $(patsubst %.c,%,$(SRCS))
@@ -7,7 +8,7 @@ all: $(PROGS)
 
 $(PROGS): $(OBJS)
 	$(E) "  LINK    " $@
-	$(Q) $(CC) $< -o $@
+	$(Q) $(CC) $@.o -o $@
 
 %.o: %.c
 	$(E) "  CC      " $@

test/test-rnd-from-file.c

+#include <stdio.h>
+#include <stdlib.h>
+
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main(int argc, char *argv[])
+{
+	const char fname_rnd[] = "random-data.o"; /* so make clean drops it */
+	const int limit = 10;
+	int counter, fd, rnd;
+
+	unlink((char *)fname_rnd);
+
+	fd = open(fname_rnd, O_RDWR | O_CREAT | O_EXCL, 0644);
+	if (fd < 0) {
+		perror("Can't open file");
+		return fd;
+	}
+
+	counter = 0;
+	while (counter++ < limit) {
+		rnd = rand();
+		write(fd, &rnd, sizeof(rnd));
+	}
+
+	counter = 0;
+	while (1) {
+		lseek(fd, 0, SEEK_SET);
+		while (counter++ < limit) {
+			read(fd, &rnd, sizeof(rnd));
+			printf("Pid: %10d Rnd: %10d\n",
+			       getpid(), rnd);
+			sleep(3);
+		}
+	}
+
+	return 0;
+}