From: Alan Cox <alan@linux.intel.com>
Date: Sat, 16 May 2015 11:01:04 +0000 (+0100)
Subject: read/write: A zero byte read or write is a no-op not an error
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=f70462b6a21c34790d4c874dcc61356c2b87b4f5;p=FUZIX.git

read/write: A zero byte read or write is a no-op not an error
---

diff --git a/Kernel/syscall_fs.c b/Kernel/syscall_fs.c
index 78799a92..24a6265c 100644
--- a/Kernel/syscall_fs.c
+++ b/Kernel/syscall_fs.c
@@ -426,6 +426,9 @@ arg_t _read(void)
 	inoptr ino;
 	uint8_t flag;
 
+	if (!nbytes)
+	        return 0;
+
 	if (!valaddr(buf, nbytes))
 	        return -1;
 	/* Set up u_base, u_offset, ino; check permissions, file num. */
@@ -486,6 +489,9 @@ arg_t _write(void)
 	inoptr ino;
 	uint8_t flag;
 
+	if (!nbytes)
+	        return 0;
+
 	if (!valaddr(buf, nbytes))
 	        return -1;
 	/* Set up u_base, u_offset, ino; check permissions, file num. */