ipc: send() for unix sockets

src/ipc/sockio.c

@@ -0,0 +1,73 @@
+/*
+ * lux - a lightweight unix-like operating system
+ * Omar Elghoul, 2024
+ * 
+ * Core Microkernel
+ */
+
+/* Socket I/O Functions */
+/* send() and recv() are implemented here */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <kernel/logger.h>
+#include <kernel/socket.h>
+#include <kernel/io.h>
+#include <kernel/sched.h>
+
+/* send(): sends a message to a socket connection
+ * params: t - calling thread
+ * params: sd - socket descriptor
+ * params: buffer - buffer containing the message
+ * params: len - size of the message
+ * params: flags - optional flags for the request
+ * returns: positive number of bytes sent, negative error code on fail
+ */
+
+ssize_t send(Thread *t, int sd, const void *buffer, size_t len, int flags) {
+    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 = self->peer;
+    if(!peer) return -EDESTADDRREQ;     // not in connection mode
+
+    sa_family_t family = self->address.sa_family;
+
+    socketLock();
+
+    if(family == AF_UNIX || family == AF_LOCAL) {
+        // simply append to the peer's inbound list
+        void **newlist = realloc(peer->inbound, (peer->inboundCount + 1) * sizeof(void *));
+        if(!newlist) {
+            socketRelease();
+            return -ENOBUFS;
+        }
+
+        void *message = malloc(len);
+        if(!message) {
+            free(newlist);
+            socketRelease();
+            return -ENOBUFS;
+        }
+
+        // and send
+        memcpy(message, buffer, len);
+        newlist[peer->inboundCount] = message;
+        peer->inboundCount++;
+        peer->inbound = newlist;
+
+        socketRelease();
+        return len;
+    } else {
+        /* TODO: handle other protocols in user space */
+        socketRelease();
+        return -ENOTCONN;
+    }
+}