add docs for syscalls. make syscall code kind-of cleaner

1 files changed, 122 insertions, 48 deletions

diff --git a/sys/syscall_pagedir.c b/sys/syscall_pagedir.c
index 33acc87..961c477 100644
--- a/sys/syscall_pagedir.c
+++ b/sys/syscall_pagedir.c
@@ -5,12 +5,13 @@
 #include "syscall.h"
 
 static int
-s_syscall_pagedir_map(
+s_get_untyped(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pml4,
         size_t payload_bytes,
         void *payload_data,
-        jove_owned_obj_t **untyped_ret)
+        jove_perm_obj_t *untyped_ret)
 {
     size_t bytes_needed = sizeof(struct syscall_pagedir_map);
     CHECK_TOOSMALL(bytes_needed, payload_bytes,
@@ -27,40 +28,44 @@ s_syscall_pagedir_map(
             "Message too small for untyped path.");
 
     errno = 0;
-    jove_owned_obj_t *untyped_obj = objdir_trygetobj(objdir,
-            payload->untyped_path, payload->untyped_pathlen);
+    jove_perm_obj_t untyped = link_try_traverse(
+            lockstack_push(lockstack, objdir_trygetobj(
+                objdir, payload->untyped_path, payload->untyped_pathlen)),
+            lockstack);
     if(errno) {
         kprintf("%s: Untyped obj failed for the reason: %s\n", __func__, errstr(errno));
         return errno;
     }
     
-    CHECK_OBJTYPE(untyped_obj, JOVE_OBJ_UNTYPED,
+    CHECK_OBJTYPE(untyped.obj, JOVE_OBJ_UNTYPED,
             "Untyped path does not point to an untyped object.");
-    jove_untyped_t *untyped_data = obj_deref(untyped_obj);
+    CHECK_OBJPERM(untyped, JOVE_PERM_MUTATE,
+            "Untyped object does not have MUTATE permission.");
+
+    jove_untyped_t *untyped_data = obj_deref(untyped.obj);
 
     if((uintptr_t)untyped_data & 0xFFF) {
         kprintf("%s: Untyped object is not page aligned.\n", __func__);
-        obj_release(untyped_obj);
         return EALIGN;
     }
     if(untyped_data->limit != 0x1000) {
         kprintf("%s: Untyped object is not page sized. (expected 0x1000 got 0x%X)\n", __func__,
                 untyped_data->limit);
-        obj_release(untyped_obj);
         return EBADSIZE;
     }
 
-    *untyped_ret = untyped_obj;
+    *untyped_ret = untyped;
     return 0;
 }
 
 static int
 s_syscall_pagedir_unmap(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pagedir,
         size_t payload_bytes,
         void *payload_data,
-        jove_owned_obj_t **none_ret)
+        jove_perm_obj_t *none_ret)
 {
     size_t bytes_needed = sizeof(struct syscall_pagedir_unmap);
     CHECK_TOOSMALL(bytes_needed, payload_bytes, 
@@ -76,117 +81,186 @@ s_syscall_pagedir_unmap(
     CHECK_TOOSMALL(bytes_needed, payload_bytes,
             "Message too small for none path");
 
-    jove_owned_obj_t *none_obj = objdir_trygetobj(objdir, 
-            payload->none_path, payload->none_pathlen);
+    jove_perm_obj_t none = link_try_traverse(
+            lockstack_push(lockstack, objdir_trygetobj(
+                objdir, payload->none_path, payload->none_pathlen)),
+            lockstack);
     if(errno) {
         kprintf("%s: None obj retrieval failed for the reason: %s\n",
                 __func__, errstr(errno));
         return errno;
     }
 
-    CHECK_OBJTYPE(none_obj, JOVE_OBJ_NONE,
+    CHECK_OBJTYPE(none.obj, JOVE_OBJ_NONE,
             "None path does not point to none object.");
-    *none_ret = none_obj;
+    *none_ret = none;
     return 0;
 }
 
 static int
 s_syscall_pagedir_map_frame(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pagedir,
         size_t payload_bytes,
         void *payload_data)
 {
-    jove_owned_obj_t *untyped_obj = NULL;
-    int sysret = s_syscall_pagedir_map(objdir, target_obj, payload_bytes, payload_data, &untyped_obj);
+    jove_perm_obj_t untyped = { .obj = NULL, .permissions = 0 };
+    int sysret = s_get_untyped(lockstack, objdir, pagedir, payload_bytes, payload_data, &untyped);
     if(sysret != 0) {
         return sysret;
     }
 
     struct syscall_pagedir_map *payload = payload_data;
-    sysret = pagedir_map_untyped_frame(target_obj, untyped_obj, payload->virtual_address, payload->flags);
+    sysret = pagedir_map_untyped_frame(pagedir, &untyped, payload->virtual_address, payload->page_flags);
 
     if(sysret == 0)
-        obj_settype(untyped_obj, JOVE_OBJ_NONE);
+        obj_settype(untyped.obj, JOVE_OBJ_NONE);
 
-    obj_release(untyped_obj);
     return sysret;
 }
 
 static int
 s_syscall_pagedir_map_table(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pagedir,
         size_t payload_bytes,
         void *payload_data)
 {
-    jove_owned_obj_t *untyped_obj = NULL;
-    int sysret = s_syscall_pagedir_map(objdir, target_obj, payload_bytes, payload_data, &untyped_obj);
+    jove_perm_obj_t untyped = { .obj = NULL, .permissions = 0 };
+    int sysret = s_get_untyped(lockstack, objdir, pagedir, payload_bytes, payload_data, &untyped);
     if(sysret != 0) {
         return sysret;
     }
 
     struct syscall_pagedir_map *payload = payload_data;
-    sysret = pagedir_map_untyped_table(target_obj, untyped_obj, payload->virtual_address);
+    sysret = pagedir_map_untyped_table(pagedir, &untyped, payload->virtual_address);
 
     if(sysret == 0)
-        obj_settype(untyped_obj, JOVE_OBJ_NONE);
+        obj_settype(untyped.obj, JOVE_OBJ_NONE);
 
-    obj_release(untyped_obj);
     return sysret;
 }
 
 static int
+s_syscall_pagedir_map_shmem(
+        lockstack_t *lockstack,
+        jove_owned_obj_t *objdir,
+        jove_owned_obj_t *pagedir,
+        size_t payload_bytes,
+        void *payload_data)
+{
+    size_t bytes_needed = sizeof(struct syscall_pagedir_map_shmem);
+    CHECK_TOOSMALL(bytes_needed, payload_bytes,
+            "Message too small for payload.");
+
+    struct syscall_pagedir_map_shmem *payload = payload_data;
+    if(payload->virtual_address > 0xFFFF800000000000ULL) {
+        kprintf("%s: Virtual address is above user limit.\n", __func__);
+        return EBADARG;
+    }
+
+    bytes_needed += payload->shmem_pathlen << 1;
+    CHECK_TOOSMALL(bytes_needed, payload_bytes,
+            "Message too small for untyped path.");
+
+    errno = 0;
+    jove_perm_obj_t shmem = link_try_traverse(
+        lockstack_push(lockstack, objdir_trygetobj(
+                objdir, payload->shmem_path, payload->shmem_pathlen)),
+        lockstack);
+    if(errno) {
+        klogf("Shared memory obj failed for the reason: %s\n", errstr(errno));
+        return errno;
+    }
+    
+    CHECK_OBJTYPE(shmem.obj, JOVE_OBJ_SHMEMORY,
+            "Shared memory path does not point to a shared memory object.");
+
+    uintmax_t shmem_value = obj_getvalue(shmem.obj);
+    uint8_t shmem_pages = shmem_value & 0xFF;
+
+    if(payload->page_offset >= shmem_pages) {
+        klogf("Page offset goes beyond size of shared memory object: (%i >= %i)\n",
+                payload->page_offset, shmem_pages);
+        return -EOOB;
+    }
+
+    return pagedir_map_shmem_frame(pagedir, &shmem, payload->page_offset, 
+            payload->virtual_address, payload->page_flags);
+}
+
+static int
 s_syscall_pagedir_unmap_frame(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pagedir,
         size_t payload_bytes,
         void *payload_data)
 {
-    jove_owned_obj_t *none_obj;
-    int sysret = s_syscall_pagedir_unmap(objdir, target_obj, payload_bytes, payload_data, &none_obj);
+    jove_perm_obj_t none;
+    int sysret = s_syscall_pagedir_unmap(lockstack, objdir, pagedir, payload_bytes, payload_data, &none);
 
     if(!sysret) return sysret;
     struct syscall_pagedir_unmap *payload = payload_data;
 
-    return pagedir_unmap_untyped_frame(target_obj, none_obj, payload->virtual_address);
+    return pagedir_unmap_untyped_frame(pagedir, none.obj, payload->virtual_address);
 }
 
 static int
 s_syscall_pagedir_unmap_table(
+        lockstack_t *lockstack,
         jove_owned_obj_t *objdir,
-        jove_owned_obj_t *target_obj,
+        jove_owned_obj_t *pagedir,
         size_t payload_bytes,
         void *payload_data)
 {
-    jove_owned_obj_t *none_obj;
-    int sysret = s_syscall_pagedir_unmap(objdir, target_obj, payload_bytes, payload_data, &none_obj);
+    jove_perm_obj_t none;
+    int sysret = s_syscall_pagedir_unmap(lockstack, objdir, pagedir, payload_bytes, payload_data, &none);
 
     if(!sysret) return sysret;
     struct syscall_pagedir_unmap *payload = payload_data;
 
-    return pagedir_unmap_untyped_table(target_obj, none_obj, payload->virtual_address);
+    return pagedir_unmap_untyped_table(pagedir, none.obj, payload->virtual_address);
 }
 
 int
-_syscall_handle_pagedir(
-        jove_owned_obj_t *pcb_obj,
-        jove_owned_obj_t *objdir,
-        jove_owned_obj_t *message_obj,
-        jove_owned_obj_t *target_obj,
-        struct syscall_header *header,
-        size_t bytes_left,
-        void *payload)
+_syscall_handle_pagedir(syscall_context_t *ctx)
 {
+    lockstack_t *lockstack = &ctx->lockstack;
+    struct syscall_header *header = ctx->header;
+    jove_owned_obj_t *objdir = ctx->objdir;
+    jove_perm_obj_t *target = &ctx->target;
+    size_t bytes_left = ctx->bytes_left;
+    void *payload = ctx->payload;
+
     switch(header->callid) {
         case SYSCALL_PAGEDIR_MAP_FRAME:
-            return s_syscall_pagedir_map_frame(objdir, target_obj, bytes_left, payload);
+            if(target->permissions & SYSCALL_PERM_PAGEDIR_MAP_FRAME)
+                return s_syscall_pagedir_map_frame(lockstack, objdir, target->obj, bytes_left, payload);
+            return -EPERM;
+
         case SYSCALL_PAGEDIR_MAP_TABLE:
-            return s_syscall_pagedir_map_table(objdir, target_obj, bytes_left, payload);
+            if(target->permissions & SYSCALL_PERM_PAGEDIR_MAP_TABLE)
+                return s_syscall_pagedir_map_table(lockstack, objdir, target->obj, bytes_left, payload);
+            return -EPERM;
+        
+        case SYSCALL_PAGEDIR_MAP_SHMEM:
+            if(target->permissions & SYSCALL_PERM_PAGEDIR_MAP_SHMEM)
+                return s_syscall_pagedir_map_shmem(lockstack, objdir, target->obj, bytes_left, payload);
+            return -EPERM;
+        
         case SYSCALL_PAGEDIR_UNMAP_FRAME:
-            return s_syscall_pagedir_unmap_frame(objdir, target_obj, bytes_left, payload);
+            if(target->permissions & SYSCALL_PERM_PAGEDIR_UNMAP_FRAME)
+               return s_syscall_pagedir_unmap_frame(lockstack, objdir, target->obj, bytes_left, payload);
+            return -EPERM;
+
         case SYSCALL_PAGEDIR_UNMAP_TABLE:
-            return s_syscall_pagedir_unmap_table(objdir, target_obj, bytes_left, payload);
+            if(target->permissions & SYSCALL_PERM_PAGEDIR_UNMAP_TABLE)
+                return s_syscall_pagedir_unmap_table(lockstack, objdir, target->obj, bytes_left, payload);
+            return -EPERM;
+
         default:
             kprintf("syscall_handle_pagedir: Pagedir does not support syscall %i\n", header->callid);
             return EBADARG;