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[PATCH v2 2/3] linux-user: Fix accept4(SOCK_NONBLOCK) syscall
From: |
Helge Deller |
Subject: |
[PATCH v2 2/3] linux-user: Fix accept4(SOCK_NONBLOCK) syscall |
Date: |
Sat, 8 Jul 2023 07:42:48 +0200 |
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 <deller@gmx.de>
---
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 10f05b1e55..9b9e3bd5e3 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));
--
2.41.0