preliminary object linking support. needs testing

3 files changed, 87 insertions, 15 deletions

diff --git a/sys/link.c b/sys/link.c
new file mode 100644
index 0000000..5be9457
--- /dev/null
+++ b/sys/link.c
@@ -0,0 +1,52 @@
+#include "link.h"
+#include "arch/x86_64/hal/obj.h"
+#include "hal/memory.h"
+
+void*
+obj_deref_linked(jove_owned_obj_t *obj)
+{
+    switch(obj_gettype(obj)) {
+        case JOVE_OBJ_LINK: return obj_deref_linked(link_deref(obj));
+        default: return obj_deref(obj);
+    }
+}
+
+uint8_t 
+obj_gettype_linked(jove_owned_obj_t *obj)
+{
+    switch(obj_gettype(obj)) {
+        case JOVE_OBJ_LINK: return obj_gettype_linked(link_deref(obj));
+        default: return obj_gettype(obj);
+    }
+}
+
+uint64_t 
+obj_getvalue_linked(jove_owned_obj_t *obj)
+{
+    switch(obj_gettype(obj)) {
+        case JOVE_OBJ_LINK: return obj_getvalue_linked(link_deref(obj));
+        default: return obj_getvalue(obj);
+    }
+}
+
+jove_owned_obj_t*
+link_deref(jove_owned_obj_t *link)
+{
+    struct obj_link *linkval = obj_deref(link);
+    return obj_take(&linkval->obj);
+}
+
+jove_owned_obj_t *link_new(jove_obj_t *tgt, jove_owned_obj_t *dst)
+{
+    struct obj_link *linkval = obj_deref(dst);
+    linkval->obj = *tgt;
+    linkval->refcount = 2;
+
+    {
+        jove_owned_obj_t *tgt_owned = obj_take(tgt);
+        obj_settype(tgt_owned, JOVE_OBJ_LINK);
+        obj_setvalue(tgt_owned, (uintptr_t)linkval);
+        obj_release(tgt_owned);
+    }
+    return dst;
+}
diff --git a/sys/link.h b/sys/link.h
new file mode 100644
index 0000000..37fa1e8
--- /dev/null
+++ b/sys/link.h
@@ -0,0 +1,21 @@
+#ifndef _JOVE_SYS_LINK_HPP
+#define _JOVE_SYS_LINK_HPP 1
+
+#include "hal/obj.h"
+
+struct obj_link
+{
+    size_t refcount;
+    jove_obj_t obj;
+};
+
+void *obj_deref_linked(jove_owned_obj_t *obj);
+uint8_t obj_gettype_linked(jove_owned_obj_t *obj);
+uint64_t obj_getvalue_linked(jove_owned_obj_t *obj);
+
+jove_owned_obj_t *link_deref(jove_owned_obj_t *link);
+jove_obj_t link_unlink(jove_owned_obj_t *link);
+
+jove_owned_obj_t *link_new(jove_obj_t *tgt, jove_owned_obj_t *dst);
+
+#endif
diff --git a/sys/syscall.c b/sys/syscall.c
index 68a5ae6..9a98030 100644
--- a/sys/syscall.c
+++ b/sys/syscall.c
@@ -4,6 +4,7 @@
 #include "hal/process.h"
 #include "jove.h"
 #include "lib/printf.h"
+#include "sys/link.h"
 #include "sys/message.h"
 
 int
@@ -33,6 +34,7 @@ static const syscall_handle_t s_syscall_handles[128] = {
     [JOVE_OBJ_FRAMEBUFFER] = _syscall_handle_generic,
     [JOVE_OBJ_VIRTTERM] = _syscall_handle_vtt,
     [JOVE_OBJ_MESSAGE] = _syscall_handle_generic,
+    [JOVE_OBJ_LINK] = _syscall_handle_generic,
 };
 
 int
@@ -55,15 +57,11 @@ syscall_handler(uintmax_t message_path_raw, uint16_t message_pathlen)
         return errno;
     }
 
-#define SYSCALL_MIDWAY_CLEANUP \
-    obj_release(message_obj); \
-    obj_release(objdir); \
-    obj_release(pcb_obj)
-
-    if(obj_gettype(message_obj) != JOVE_OBJ_MESSAGE) {
+    int sysret = 0;
+    if(obj_gettype_linked(message_obj) != JOVE_OBJ_MESSAGE) {
         kprintf("syscall: Process %i tried to call syscall with invalid object: %P\n", pcb_pid(pcb), message_path, message_pathlen);
-        SYSCALL_MIDWAY_CLEANUP;
-        return EBADOBJ;
+        sysret = EBADOBJ;
+        goto release_return;
     }
 
     size_t messagelen = message_len(message_obj);
@@ -75,18 +73,17 @@ syscall_handler(uintmax_t message_path_raw, uint16_t message_pathlen)
     if(bytes_left < 0) {
         //Target path exceeds message length.
         kprintf("syscall: Process %i tried to call syscall with OOB target path.\n", pcb_pid(pcb));
-        SYSCALL_MIDWAY_CLEANUP;
-        return EBADPATH;
+        sysret = EBADPATH;
+        goto release_return;
     }
     jove_owned_obj_t *target = objdir_getobj(objdir, header->path, header->pathlen);
     if(target == 0) {
         //Could not find payload target in pcb rootdir.
         kprintf("syscall: Process %i tried to call syscall with bad target path %P\n", 
                 pcb_pid(pcb), header->path, header->pathlen);
-        SYSCALL_MIDWAY_CLEANUP;
-        return errno;
+        sysret = errno;
+        goto release_return;
     }
-    int sysret = 0;
 
     uint8_t target_type = obj_gettype(target);
     if(target_type > 0x7F) {
@@ -104,8 +101,10 @@ syscall_handler(uintmax_t message_path_raw, uint16_t message_pathlen)
                     pcb_obj, objdir, message_obj, target, 
                     header, bytes_left, messagedata + header_bytes);
     }
-
     obj_release(target);
-    SYSCALL_MIDWAY_CLEANUP;
+release_return:
+    obj_release(message_obj);
+    obj_release(objdir);
+    obj_release(pcb_obj);
     return sysret;
 }