From: Alan Cox <alan@linux.intel.com>
Date: Sat, 22 Dec 2018 11:17:38 +0000 (+0000)
Subject: dup2: Fix two bugs
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=014946e511a68071c45fac3872d0a5ba25e2cc15;p=FUZIX.git

dup2: Fix two bugs

1.	dup2(x,x) corrupted all the counts we closed the object then referenced
it

2.	dup2() returns the new file handle not 0 on success
---

diff --git a/Kernel/syscall_fs.c b/Kernel/syscall_fs.c
index 60ea8c97..5e9d2e9b 100644
--- a/Kernel/syscall_fs.c
+++ b/Kernel/syscall_fs.c
@@ -206,20 +206,24 @@ arg_t _dup2(void)
 {
 
 	if (getinode(oldd) == NULLINODE)
-		return (-1);
+		return -1;
 
 	if (newd < 0 || newd >= UFTSIZE) {
 		udata.u_error = EBADF;
-		return (-1);
+		return -1;
 	}
 
+	/* No-op - but we must not close and dup so catch it */
+	if (newd == oldd)
+		return oldd;
+
 	if (udata.u_files[newd] != NO_FILE)
 		doclose(newd);
 
 	udata.u_files[newd] = udata.u_files[oldd];
 	++of_tab[udata.u_files[oldd]].o_refs;
 
-	return (0);
+	return newd;
 }
 
 #undef oldd