From dca4c8384d68bbf5d67f50a5446865d92d61f032 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 8 Jul 2023 07:24:00 +0200 Subject: [PATCH] linux-user: Fix accept4(SOCK_NONBLOCK) syscall The Linux accept4() syscall allows two flags only: SOCK_NONBLOCK and SOCK_CLOEXEC, and returns -EINVAL if any other bits have been set. Change the qemu implementation accordingly, which means we can not use the fcntl_flags_tbl[] translation table which allows too many other values. Beside the correction in behaviour, this actually fixes the accept4() emulation for hppa, mips and alpha targets for which SOCK_NONBLOCK is different than TARGET_SOCK_NONBLOCK (aka O_NONBLOCK). The fix can be verified with the testcase of the debian lwt package, which hangs forever in a read() syscall without this patch. Signed-off-by: Helge Deller Reviewed-by: Richard Henderson --- linux-user/syscall.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 10f05b1e556d..9b9e3bd5e374 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3440,7 +3440,17 @@ static abi_long do_accept4(int fd, abi_ulong target_addr, abi_long ret; int host_flags; - host_flags = target_to_host_bitmask(flags, fcntl_flags_tbl); + if (flags & ~(TARGET_SOCK_CLOEXEC | TARGET_SOCK_NONBLOCK)) { + return -TARGET_EINVAL; + } + + host_flags = 0; + if (flags & TARGET_SOCK_NONBLOCK) { + host_flags |= SOCK_NONBLOCK; + } + if (flags & TARGET_SOCK_CLOEXEC) { + host_flags |= SOCK_CLOEXEC; + } if (target_addr == 0) { return get_errno(safe_accept4(fd, NULL, NULL, host_flags));