From: Peter Maydell <peter.mayd...@linaro.org> The POSIX standard mandates that for a connected socket recvfrom() must ignore the msg_name and msg_namelen fields. This is awkward for QEMU because we will attempt to copy them from guest address space. Handle this by not immediately returning a TARGET_EFAULT if the copy failed, but instead passing a known-bad address to the host kernel, which can then return EFAULT or ignore the value appropriately.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> Signed-off-by: Riku Voipio <riku.voi...@linaro.org> --- linux-user/syscall.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 9d18326..51f558d 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3472,7 +3472,14 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, ret = target_to_host_sockaddr(fd, msg.msg_name, tswapal(msgp->msg_name), msg.msg_namelen); - if (ret) { + if (ret == -TARGET_EFAULT) { + /* For connected sockets msg_name and msg_namelen must + * be ignored, so returning EFAULT immediately is wrong. + * Instead, pass a bad msg_name to the host kernel, and + * let it decide whether to return EFAULT or not. + */ + msg.msg_name = (void *)-1; + } else if (ret) { goto out2; } } else { @@ -3534,7 +3541,7 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, } if (!is_error(ret)) { msgp->msg_namelen = tswap32(msg.msg_namelen); - if (msg.msg_name != NULL) { + if (msg.msg_name != NULL && msg.msg_name != (void *)-1) { ret = host_to_target_sockaddr(tswapal(msgp->msg_name), msg.msg_name, msg.msg_namelen); if (ret) { -- 2.1.4