From d9399944e832d6cb782beb08eb69e3b0bf0a1f3c Mon Sep 17 00:00:00 2001
From: fslongjin <fslongjin@vip.qq.com>
Date: Wed, 27 Apr 2022 21:00:05 +0800
Subject: [PATCH] =?UTF-8?q?:wrench:=20=E6=A0=A1=E9=AA=8C=E6=96=87=E4=BB=B6?=
 =?UTF-8?q?=E6=8F=8F=E8=BF=B0=E7=AC=A6=E6=98=AF=E5=90=A6=E5=AD=98=E5=9C=A8?=
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---
 kernel/syscall/syscall.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/kernel/syscall/syscall.c b/kernel/syscall/syscall.c
index 754792b6..4ea2cb5a 100644
--- a/kernel/syscall/syscall.c
+++ b/kernel/syscall/syscall.c
@@ -218,7 +218,9 @@ uint64_t sys_close(struct pt_regs *regs)
     // 校验文件描述符范围
     if (fd_num < 0 || fd_num > PROC_MAX_FD_NUM)
         return -EBADF;
-
+    // 文件描述符不存在
+    if (current_pcb->fds[fd_num] == NULL)
+        return -EBADF;
     struct vfs_file_t *file_ptr = current_pcb->fds[fd_num];
     uint64_t ret;
     // If there is a valid close function
@@ -232,17 +234,17 @@ uint64_t sys_close(struct pt_regs *regs)
 
 /**
  * @brief 从文件中读取数据
- * 
+ *
  * @param fd_num regs->r8 文件描述符号
  * @param buf regs->r9 输出缓冲区
  * @param count regs->r10 要读取的字节数
- * 
- * @return uint64_t 
+ *
+ * @return uint64_t
  */
 uint64_t sys_read(struct pt_regs *regs)
 {
     int fd_num = (int)regs->r8;
-    void *buf = (void*)regs->r9;
+    void *buf = (void *)regs->r9;
     int64_t count = (int64_t)regs->r10;
 
     // kdebug("sys read: fd=%d", fd_num);
@@ -251,6 +253,10 @@ uint64_t sys_read(struct pt_regs *regs)
     if (fd_num < 0 || fd_num > PROC_MAX_FD_NUM)
         return -EBADF;
 
+    // 文件描述符不存在
+    if (current_pcb->fds[fd_num] == NULL)
+        return -EBADF;
+
     if (count < 0)
         return -EINVAL;