fixes to work on dept machine

1 files changed, 10 insertions, 4 deletions

diff --git a/kernel/api/syscall.c b/kernel/api/syscall.c
index 7c76e51..c5fea6d 100644
--- a/kernel/api/syscall.c
+++ b/kernel/api/syscall.c
@@ -77,10 +77,11 @@ static long sys_read(read_args_t *args)
     ERROR_OUT_RET(ret);
 
     // Allocate a temporary buffer (a page-aligned block of n pages that are enough space to store the number of bytes to read)
-    size_t size_in_pages = 0;
-    while(++size_in_pages * PAGE_SIZE < kargs.nbytes)
-        ;
-    void *addr = page_alloc_n(size_in_pages);
+    // size_t size_in_pages = 0;
+    // while(++size_in_pages * PAGE_SIZE < kargs.nbytes)
+    //     ;
+    size_t size_in_pages = ADDR_TO_PN(PAGE_ALIGN_UP(kargs.nbytes));
+    char *addr = (char *)page_alloc_n(size_in_pages);
     if (!addr)
     {
         ret = -ENOMEM;
@@ -134,6 +135,11 @@ static long sys_write(write_args_t *args)
     long ret = copy_from_user(&kargs, args, sizeof(kargs));
     ERROR_OUT_RET(ret);
 
+    if (kargs.nbytes == 0)
+    {
+        return 0;
+    }
+    
     // Allocate a temporary buffer (a page-aligned block of n pages that are enough space to store the number of bytes to write)
     size_t size_in_pages = 0;
     while(++size_in_pages * PAGE_SIZE < kargs.nbytes)