From 0236f00d26e56d390c8651986e724473dbf9a615 Mon Sep 17 00:00:00 2001
From: tkchia <tkchia@users.noreply.github.com>
Date: Sat, 16 Jul 2022 17:16:45 +0000
Subject: [PATCH] plat/msdos86: fix: read() on O_TEXT fd should try to return
any errors signaled by low-level read
---
plat/msdos86/libsys/read.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/plat/msdos86/libsys/read.c b/plat/msdos86/libsys/read.c
index 71711832e..5075958bd 100644
--- a/plat/msdos86/libsys/read.c
+++ b/plat/msdos86/libsys/read.c
@@ -33,6 +33,10 @@ ssize_t read(int fd, void* buffer, size_t count)
* file pointer to just before the ^Z. Also set an internal flag
* for the fd so that we do not try to read any further (until e.g.
* a seek happens).
+ *
+ * If a low-level read returns an error (-1) before anything has
+ * actually been read, we can pass the error indication (-1) up to
+ * the caller.
*/
p = buffer;
tot = 0;
@@ -41,7 +45,7 @@ ssize_t read(int fd, void* buffer, size_t count)
{
r = _sys_rawread(fd, p, count - (p - (char *)buffer));
if (r <= 0)
- return tot;
+ return tot ? tot : r;
q = memchr(p, 0x1a, (size_t)r);
if (q)