qemu/0037-linux-user-lseek-explicitly-cast-en.patch

From f4310e6dc96e9036cd40d6b804019c4edbbb97f5 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Thu, 13 Dec 2012 14:29:22 +0100
Subject: [PATCH] linux-user: lseek: explicitly cast end offsets to signed

When doing lseek, SEEK_END indicates that the offset is a signed variable
that is usually negative, while and other SEEK indicates that it's unsigned.

When converting from 32bit to 64bit parameters, we need to take this into
account and enable SEEK_END to be negative, while other SEEKs usually indicate
absolute position which we need to maintain as unsigned.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 linux-user/syscall.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index c1eceb2..259fed4 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5648,9 +5648,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_ulong arg1,
     case TARGET_NR_oldstat:
         goto unimplemented;
 #endif
-    case TARGET_NR_lseek:
-        ret = get_errno(lseek(arg1, arg2, arg3));
+    case TARGET_NR_lseek: {
+        off_t off = arg2;
+        if (arg3 == SEEK_END) {
+            off = (abi_long)arg2;
+        }
+        ret = get_errno(lseek(arg1, off, arg3));
         break;
+    }
 #if defined(TARGET_NR_getxpid) && defined(TARGET_ALPHA)
     /* Alpha specific */
     case TARGET_NR_getxpid: