1 files changed, 21 insertions, 27 deletions

diff --git a/kernel/vm/mmap.c b/kernel/vm/mmap.c
index ce932de..a298df4 100644
--- a/kernel/vm/mmap.c
+++ b/kernel/vm/mmap.c
@@ -70,7 +70,7 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
     }
 
     // check if len is not zero (len is an unsigned value, so it is always positive)
-    if (len == 0)
+    if ((ssize_t) len <= 0)
     {
         return -EINVAL;
     }
@@ -87,8 +87,8 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
         return -EINVAL;
     }
 
-    // check if fd is not a valid file descriptor and MAP_ANON was not set
-    if (fd < 0 && (flags & MAP_ANON) == 0)
+    // check if the fd is valid and MAP_ANON was not set
+    if (((fd < 0 || fd >= NFILES) || curproc->p_files[fd] == NULL) && !(flags & MAP_ANON))
     {
         return -EBADF;
     }
@@ -96,10 +96,10 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
     // check if a file mapping was requested, but fd is not open for reading
     // file error checking is done in if statement below
     file_t *file = NULL;
-    if (fd >= 0 && (flags & MAP_ANON) == 0)
+    if (fd >= 0 && fd < NFILES)
     {
         // get the file and check if it is valid
-        file = fget(fd);
+        file = curproc->p_files[fd];
         if (file == NULL)
         {
             return -EBADF;
@@ -110,7 +110,6 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
         // check if the file's vnode's mmap operation doesn't exist
         if (file->f_vnode->vn_ops == NULL || file->f_vnode->vn_ops->mmap == NULL)
         {
-            fput(&file);
             return -ENODEV;
         }
 
@@ -119,32 +118,26 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
         // check if thef FMODE_READ flag is not set
         if ((file->f_mode & FMODE_READ) == 0)
         {
-            fput(&file);
             return -EACCES;
         }
         
         // check if append mode is set and PROT_WRITE is set
         if ((prot & PROT_WRITE) && (file->f_mode & FMODE_APPEND))
         {
-            fput(&file);
             return -EACCES;
         }
 
-        // check if MAP_SHARED was requested and PROT_WRITE is set, but fd is not open in read/write (O_RDWR) mode
-        if ((flags & MAP_SHARED) && (prot & PROT_WRITE) && (file->f_mode & FMODE_READ) == 0)
+        // if MAP_SHARED was requested and PROT_WRITE is set, but fd is not open in read/write (O_RDWR) mode.
+        if ((flags & MAP_SHARED) && (prot & PROT_WRITE) && (file->f_mode & FMODE_WRITE) == 0)
         {
-            fput(&file);
             return -EACCES;
         }
 
         // check if PROT_WRITE is set, but the file has FMODE_APPEND specified
         if ((prot & PROT_WRITE) && (file->f_mode & FMODE_APPEND))
         {
-            fput(&file);
             return -EACCES;
         }
-
-        fput(&file);
     }
 
 
@@ -167,20 +160,18 @@ long do_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off,
         return err;
     }
 
-    // set ret if it was provided
     void *start = PN_TO_ADDR(vma->vma_start);
-    if (ret)
-    {
-        *ret = start;
-    }
-
     // flush the TLB
     tlb_flush_range(
         (uintptr_t) start,
         PAGE_SIZE * (vma->vma_end - vma->vma_start)
     );
 
-    // return 0 on success
+    // set ret if it was provided and return 0 on success
+    if (ret)
+    {
+        *ret = start;
+    }
     return 0;
 }
 
@@ -212,13 +203,17 @@ long do_munmap(void *addr, size_t len)
     }
 
     // Check if len is in bounds
-    if (len > USER_MEM_HIGH || len == 0)
+    if (len > USER_MEM_HIGH || len <= 0)
     {
         return -EINVAL;
     }
 
     // Check if the addr is out of range of the user address space
-    if ((uintptr_t)addr < USER_MEM_LOW || (uintptr_t)addr + len > USER_MEM_HIGH)
+    if (
+        (uintptr_t)addr < USER_MEM_LOW  
+        || (uintptr_t)addr > USER_MEM_HIGH
+        || (uintptr_t)addr + len > USER_MEM_HIGH
+        )
     {
         return -EINVAL;
     }
@@ -227,9 +222,8 @@ long do_munmap(void *addr, size_t len)
     size_t start = ADDR_TO_PN(addr);
     size_t end = ADDR_TO_PN(PAGE_ALIGN_UP((uintptr_t)addr + len));
     long ret = vmmap_remove(
-        curproc->p_vmmap, 
-        start, 
-        end - start
-    );
+        curproc->p_vmmap,
+        start,
+        end - start);
     return ret;
 }
\ No newline at end of file