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[PULL,6/7] linux-user: fix the errno value in print_syscall_err()

Message ID 20200714073259.1464675-7-laurent@vivier.eu
State New
Headers show
Series [PULL,1/7] linux-user: Use EPROTONOSUPPORT for unimplemented netlink protocols | expand

Commit Message

Laurent Vivier July 14, 2020, 7:32 a.m. UTC 
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>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Message-Id: <20200708152435.706070-2-laurent@vivier.eu>
---
 linux-user/strace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 39554d903911..7769f53bd5ed 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);