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Date:      Sat, 27 Jul 2013 21:10:31 GMT
From:      dpl@FreeBSD.org
To:        svn-soc-all@FreeBSD.org
Subject:   socsvn commit: r255234 - soc2013/dpl
Message-ID:  <201307272110.r6RLAVQs010037@socsvn.freebsd.org>
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Author: dpl
Date: Sat Jul 27 21:10:31 2013
New Revision: 255234
URL: http://svnweb.FreeBSD.org/socsvn/?view=rev&rev=255234

Log:
  This toy implementation it's almost working.
  There's only a problem when reading back from buf[] the return value of sum_().
  

Modified:
  soc2013/dpl/caller.c

Modified: soc2013/dpl/caller.c
==============================================================================
--- soc2013/dpl/caller.c	Sat Jul 27 20:47:01 2013	(r255233)
+++ soc2013/dpl/caller.c	Sat Jul 27 21:10:31 2013	(r255234)
@@ -10,87 +10,127 @@
 #include <stdlib.h>
 #include <strings.h>
 
+
+struct pollfd fdread[1], fdwrite[1];
 pid_t child = 0;
 int sv[2], i;
 
-/* commands will live here */
-/* I will malloc it this afternoon */
-int buf[32];
+int *buf[32];
 
 pid_t startChild();
-void worker();
-void setSignals();
 void waitCommand();
-void * command();
 void killChild();
 
+/* Toy lib */
+int sum(int a);
+int sum_(int a);
+
 int
 main()
 {
-	if(child == 0)
-		child = startChild();
-	if(child < 0){
-		perror("error");
-		exit(1);
-	}
-	
+	int ret, a = 1;
+	ret = sum(a);
+	fflush(stdout);
+	printf("ret: %d (should be 2)\n", ret);
+	fflush(stdout);
+
 	atexit(killChild);
 	return 0;
 }
 
-int startChild()
+int sum(int a)
 {
-	bzero(&buf, sizeof(buf));
-	if( socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0 )
-		return -1;
-
-	if( (child = fork()) == -1 ) {
-		return -1;
-	} else if (child == 0){
-		worker();
+	/* Caller overhead */
+	/* Much better if we do this in a function */
+	int ptr = (int)sum_;
+	fdwrite[0].fd = sv[0];
+	fdwrite[0].events = POLLOUT;
+	fdwrite[0].revents = 0;
+	fdread[0].fd = sv[0];
+	fdread[0].events = POLLIN|POLLPRI;
+	fdread[0].revents = 0;
+	if( child == 0)
+		startChild();
+
+	/* Real stuff */
+	buf[0] = &ptr;
+	buf[1] = &a;
+
+	/* Should be in a function as well */
+	/* sendAndWait() (?) */
+	while(1){
+		if(poll(fdwrite, 1, 0) > 0 ){
+			write(sv[0], buf, sizeof(buf));
+			break;
+		}
 	}
-	return child;
+	/* Here, the stuff gets done in child. */
+	while(1){
+		if(poll(fdread, 1, 0) > 0 ){
+			read(sv[0], buf, sizeof(buf));
+			break;
+		}
+	}
+	printf("done: %d\n", *buf[0]);
+
+	return *buf[0];
 }
 
-void worker(){
-	cap_rights_limit(STDIN_FILENO, CAP_WRITE);
-	close(STDIN_FILENO);
-	close(STDERR_FILENO);
-
-	waitCommand();
-	signal(
-	/* Should we call signal() to exit more cleanly? */
+int sum_(int a)
+{
+	return ++a;
 }
 
+int startChild()
+{
+	socketpair(PF_LOCAL, SOCK_STREAM, 0, sv);
+	if( (child = fork()) == 0 ){
+		cap_rights_limit(STDOUT_FILENO, CAP_WRITE);
+		close(STDIN_FILENO);
+		close(STDERR_FILENO);
+		cap_enter();
+		waitCommand();
+	}
+
+	return child;
+}
 
 /* Wait for commands, and execute them */
 void
 waitCommand()
 {
-	int p;
-	pid_t pid;
-	struct pollfd fds[1];
-	fds[0].fd = sv[1];
-	fds[0].events = POLLIN|POLLPRI|POLLOUT;
-	fds[0].revents = 0;
-	
+	struct pollfd fdread[1], fdwrite[1];
+	fdread[0].fd = sv[1];
+	fdread[0].events = POLLIN|POLLPRI;
+	fdread[0].revents = 0;
+	fdwrite[0].fd = sv[1];
+	fdwrite[0].events = POLLOUT;
+	fdwrite[0].revents = 0;
 	while(1) {
-		p = poll(fds, 1, 0);
-		if (p > 0){
-			if( fds[0].revents & POLLIN || fds[0].revents & POLLPRI){
-				/* Read command */
-				read(sv[1], buf, sizeof(buf));	
-			} else if( fds[0].revents & POLLOUT) {
-				/* Write answer */
+		while(1){
+			if( poll(fdread, 1, 0) > 0){
+				read(sv[1], buf, sizeof(buf));
+				break;
 			}
 		}
-	}
-}
 
+		if( (void *)*buf[0] == (void *) sum_ ){
+			/* This is a C exercise }:-) */
+			int ret = ((int (*) (int)) *buf[0])(*buf[1]);
+			/* int ret = sum_(*buf[1]); */
+			printf("ret:%d\n", ret);
+			fflush(stdout);
+			bzero(&buf, sizeof(buf));
+			buf[0] = &ret;
+		}
 
-void *
-command(){
-	return NULL;
+		while(1) {
+			if (poll(fdwrite, 1, 0) > 0){
+				write(sv[1], buf, sizeof(buf));
+				break;
+			}
+		}
+	}
 }
 
 void

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