From f22a61964e71d32c9dc472e83c75abca96c58d1c Mon Sep 17 00:00:00 2001
From: pumnflqv2 <ggdxz77@163.com>
Date: Sun, 26 Jun 2022 21:34:53 +0800
Subject: [PATCH] ADD file via upload

---
 fs/fcntl.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 fs/fcntl.c

diff --git a/fs/fcntl.c b/fs/fcntl.c
new file mode 100644
index 0000000..c201aa8
--- /dev/null
+++ b/fs/fcntl.c
@@ -0,0 +1,75 @@
+/*
+ *  linux/fs/fcntl.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <asm/segment.h>
+
+#include <fcntl.h>
+#include <sys/stat.h>
+
+extern int sys_close(int fd);
+
+static int dupfd(unsigned int fd, unsigned int arg)
+{
+	if (fd >= NR_OPEN || !current->filp[fd])
+		return -EBADF;
+	if (arg >= NR_OPEN)
+		return -EINVAL;
+	while (arg < NR_OPEN)
+		if (current->filp[arg])
+			arg++;
+		else
+			break;
+	if (arg >= NR_OPEN)
+		return -EMFILE;
+	current->close_on_exec &= ~(1<<arg);
+	(current->filp[arg] = current->filp[fd])->f_count++;
+	return arg;
+}
+
+int sys_dup2(unsigned int oldfd, unsigned int newfd)
+{
+	sys_close(newfd);
+	return dupfd(oldfd,newfd);
+}
+
+int sys_dup(unsigned int fildes)
+{
+	return dupfd(fildes,0);
+}
+
+int sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
+{	
+	struct file * filp;
+
+	if (fd >= NR_OPEN || !(filp = current->filp[fd]))
+		return -EBADF;
+	switch (cmd) {
+		case F_DUPFD:
+			return dupfd(fd,arg);
+		case F_GETFD:
+			return (current->close_on_exec>>fd)&1;
+		case F_SETFD:
+			if (arg&1)
+				current->close_on_exec |= (1<<fd);
+			else
+				current->close_on_exec &= ~(1<<fd);
+			return 0;
+		case F_GETFL:
+			return filp->f_flags;
+		case F_SETFL:
+			filp->f_flags &= ~(O_APPEND | O_NONBLOCK);
+			filp->f_flags |= arg & (O_APPEND | O_NONBLOCK);
+			return 0;
+		case F_GETLK:	case F_SETLK:	case F_SETLKW:
+			return -1;
+		default:
+			return -1;
+	}
+}