From dc01e2cbfb290198c03514fe51ed32c1098b774f Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 21 Feb 2014 22:25:26 -0500 Subject: [PATCH] add fallback emulation for accept4 on old kernels the other atomic FD_CLOEXEC interfaces (dup3, pipe2, socket) already had such emulation in place. the justification for doing the emulation here is the same as for the other functions: it allows applications to simply use accept4 rather than having to have their own fallback code for ENOSYS/EINVAL (which one you get is arch-specific!) and there is no reasonable way an application could benefit from knowing the operation is emulated/non-atomic since there is no workaround at the application level for non-atomicity (that is the whole reason these interfaces were added). --- src/network/accept4.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/network/accept4.c b/src/network/accept4.c index 6b5c16ce..285d8588 100644 --- a/src/network/accept4.c +++ b/src/network/accept4.c @@ -1,9 +1,20 @@ #define _GNU_SOURCE #include +#include +#include #include "syscall.h" #include "libc.h" int accept4(int fd, struct sockaddr *restrict addr, socklen_t *restrict len, int flg) { - return socketcall_cp(accept4, fd, addr, len, flg, 0, 0); + if (!flg) return accept(fd, addr, len); + int ret = socketcall_cp(accept4, fd, addr, len, flg, 0, 0); + if (ret>=0 || (errno != ENOSYS && errno != EINVAL)) return ret; + ret = accept(fd, addr, len); + if (ret<0) return ret; + if (flg & SOCK_CLOEXEC) + __syscall(SYS_fcntl, ret, F_SETFD, FD_CLOEXEC); + if (flg & SOCK_NONBLOCK) + __syscall(SYS_fcntl, ret, F_SETFL, O_NONBLOCK); + return ret; } -- 2.25.1