linux-user: fix the errno value in print_syscall_err()

[PATCH] linux-user: fix the errno value in print_syscall_err()

Laurent Vivier posted 1 patch 3 years, 9 months ago

Download mbox

Test checkpatch passed

Test docker-mingw@fedora passed

Test FreeBSD passed

Test docker-quick@centos7 passed

Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20200707171115.533166-1-laurent@vivier.eu

Maintainers: Laurent Vivier <laurent@vivier.eu>

linux-user/strace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Expand all Fold all

[PATCH] linux-user: fix the errno value in print_syscall_err()

Posted by Laurent Vivier 3 years, 9 months ago

errno of the target is returned as a negative value by the syscall,
not in the host errno variable.

The emulation of the target syscall can return an error while the
host doesn't set an errno value. Target errnos and host errnos can
also differ in some cases.

Fixes: c84be71f6854 ("linux-user: Extend strace support to enable argument printing after syscall execution")
Cc: Filip.Bozuta@syrmia.com
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/strace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 5235b2260cdd..b42664bbd180 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -731,7 +731,7 @@ print_syscall_err(abi_long ret)
 
     qemu_log(" = ");
     if (ret < 0) {
-        qemu_log("-1 errno=%d", errno);
+        qemu_log("-1 errno=%d", (int)-ret);
         errstr = target_strerror(-ret);
         if (errstr) {
             qemu_log(" (%s)", errstr);
-- 
2.26.2