From 5ab3b18865eb813d433a6c0687dfa1f62a1b6055 Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Fri, 9 Oct 2026 16:50:13 -0400
Subject: add ipc send/recv mechanism for kernel objects.

---
 sys/objdir.c      |  7 ++++++
 sys/objdir.h      |  1 +
 sys/syscall_pcb.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

(limited to 'sys')

diff --git a/sys/objdir.c b/sys/objdir.c
index c448e85..eab935f 100644
--- a/sys/objdir.c
+++ b/sys/objdir.c
@@ -112,3 +112,10 @@ objdir_trygetobj(
     }
 }
 
+void
+objdir_swapobj(jove_owned_obj_t *a, jove_owned_obj_t *b)
+{
+    jove_owned_obj_t buffer_obj = *a;
+    *a = *b;
+    *b = buffer_obj;
+}
diff --git a/sys/objdir.h b/sys/objdir.h
index 54e9618..e2ae7ef 100644
--- a/sys/objdir.h
+++ b/sys/objdir.h
@@ -23,5 +23,6 @@ jove_owned_obj_t *objdir_getobj(jove_owned_obj_t *objdir_obj, const uint16_t *pa
 /*Same as objdir_getobj but does not block if child objects are locked.*/
 jove_owned_obj_t *objdir_trygetobj(jove_owned_obj_t *objdir_obj, const uint16_t *path, size_t path_len);
 
+void objdir_swapobj(jove_owned_obj_t *a, jove_owned_obj_t *b);
 
 #endif
diff --git a/sys/syscall_pcb.c b/sys/syscall_pcb.c
index a37e4bb..4fe557b 100644
--- a/sys/syscall_pcb.c
+++ b/sys/syscall_pcb.c
@@ -1,4 +1,6 @@
 #include "api/error.h"
+#include "api/obj.h"
+#include "api/syscall.h"
 #include "jove.h"
 #include "lib/printf.h"
 #include "proc/process.h"
@@ -18,6 +20,66 @@ s_syscall_pcb_yield(jove_owned_obj_t *pcb_obj,
     return scheduler_yield(subject_pid);
 }
 
+int
+s_syscall_pcb_send(jove_owned_obj_t *pcb_obj,
+                   lockstack_t *lockstack,
+                   jove_owned_obj_t *objdir_obj,
+                   size_t bytes_left,
+                   void *payload_data)
+{
+    size_t bytes_needed = sizeof(struct syscall_pcb_send);
+    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload");
+
+    struct syscall_pcb_send *payload = payload_data;
+    bytes_needed += payload->send_path_length;
+    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for subject path");
+
+    jove_perm_obj_t subject_objdir = link_try_traverse_objdir(
+        objdir_obj, lockstack, payload->send_path_length - 1, payload->send_path);
+    if(errno) {
+        klogf("Unable to get subject %P objdir : %s\n",
+              payload->send_path, payload->send_path_length, errstr(errno));
+        return -errno;
+    }
+    CHECK_OBJPERM(subject_objdir, SYSCALL_PERM_PCB_SEND_OBJDIR, "Subject objdir does not permit send");
+
+    jove_owned_obj_t *subject = objdir_trygetlocal(subject_objdir.obj,
+                                                   payload->send_path[payload->send_path_length-1]);
+    if(subject == 0) {
+        klogf("Unable to get subject %P object : %s\n",
+              payload->send_path, payload->send_path_length, errstr(errno));
+        return -errno;
+    }
+
+    return pcb_send(obj_deref(pcb_obj), payload->send_target, subject, payload->send_timeout);
+}
+
+int
+s_syscall_pcb_recv(jove_owned_obj_t *pcb_obj,
+                   lockstack_t *lockstack,
+                   jove_owned_obj_t *objdir_obj,
+                   size_t bytes_left,
+                   void *payload_data)
+{
+    size_t bytes_needed = sizeof(struct syscall_pcb_recv);
+    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload");
+
+    struct syscall_pcb_recv *payload = payload_data;
+    bytes_needed += payload->recv_path_length * sizeof(objpath_part_t);
+    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for destination path");
+
+    jove_perm_obj_t destination = link_try_traverse_objdir(
+        objdir_obj, lockstack, payload->recv_path_length, payload->recv_path);
+    if(errno) {
+        klogf("Unable to get destination %P : %s\n",
+              payload->recv_path, payload->recv_path_length, errstr(errno));
+        return -errno;
+    }
+    CHECK_OBJPERM(destination, SYSCALL_PERM_PCB_RECV_DST, "Destination object does not permit recv.");
+
+    return pcb_recv(obj_deref(pcb_obj), payload->recv_target, destination.obj, payload->recv_timeout);
+}
+
 int
 _syscall_handle_pcb(syscall_context_t *ctx)
 {
@@ -27,6 +89,18 @@ _syscall_handle_pcb(syscall_context_t *ctx)
                 return s_syscall_pcb_yield(ctx->target.obj, ctx->bytes_left, ctx->payload);
             return -EPERM;
 
+        case SYSCALL_PCB_SEND:
+            if(ctx->target.permissions & SYSCALL_PERM_PCB_SEND)
+                return s_syscall_pcb_send(
+                    ctx->target.obj, &ctx->lockstack, ctx->objdir, ctx->bytes_left, ctx->payload);
+            return -EPERM;
+
+        case SYSCALL_PCB_RECV:
+            if(ctx->target.permissions & SYSCALL_PERM_PCB_RECV)
+                return s_syscall_pcb_recv(
+                    ctx->target.obj, &ctx->lockstack, ctx->objdir, ctx->bytes_left, ctx->payload);
+            return -EPERM;
+
         default:
             return -EBADCALL;
     }
-- 
cgit v1.2.3