ipc: socket connect()

src/include/kernel/socket.h

@@ -50,10 +50,11 @@ typedef struct SocketDescriptor {
     Process *process;
     struct sockaddr address;
     bool listener;
-    int type, protocol, backlog;
+    int type, protocol, backlogMax, backlogCount;
     int inboundCount, outboundCount;
     void **inbound, **outbound;
-    struct SocketDescriptor *peer;
+    struct SocketDescriptor **backlog;  // for incoming connections via connect()
+    struct SocketDescriptor *peer;      // for peer-to-peer connections
 } SocketDescriptor;
 
 void socketInit();

src/ipc/connection.c

@@ -0,0 +1,50 @@
+/*
+ * lux - a lightweight unix-like operating system
+ * Omar Elghoul, 2024
+ * 
+ * Core Microkernel
+ */
+
+/* Socket Connection Functions */
+/* connect(), listen(), and accept() are implemented here */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <platform/lock.h>
+#include <kernel/logger.h>
+#include <kernel/socket.h>
+#include <kernel/io.h>
+#include <kernel/sched.h>
+
+/* connect(): creates a socket connection
+ * params: t - calling thread, NULL for kernel threads
+ * params: sd - socket descriptor
+ * params: addr - peer address
+ * params: len - length of peer address
+ * returns: zero on success, negative error code on fail
+ */
+
+int connect(Thread *t, int sd, const struct sockaddr *addr, socklen_t len) {
+    Process *p;
+    if(t) p = getProcess(t->pid);
+    else p = getProcess(getPid());
+    if(!p) return -ESRCH;
+
+    if(!p->io[sd].valid || !p->io[sd].data || (p->io[sd].type != IO_SOCKET))
+        return -ENOTSOCK;
+
+    SocketDescriptor *self = (SocketDescriptor *) p->io[sd].data;
+    SocketDescriptor *peer = getLocalSocket(addr, len);
+
+    if(!peer) return -EADDRNOTAVAIL;
+    if(!peer->listener || !peer->backlogMax || !peer->backlog) return -ECONNREFUSED;
+    if(peer->backlogCount >= peer->backlogMax) return -ETIMEDOUT;
+
+    // at this point we're sure it's safe to create a connection
+    socketLock();
+    peer->backlog[peer->backlogCount] = self;
+    peer->backlogCount++;
+    socketRelease();
+    return 0;
+}