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ext/sockets: using accept4 wheneever possible for php_accept_connect … #19268

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Merged
merged 1 commit into from
Jul 27, 2025
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ext/sockets: using accept4 wheneever possible for php_accept_connect … #19268

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2 changes: 1 addition & 1 deletion ext/sockets/config.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ PHP_ARG_ENABLE([sockets],
[Enable sockets support])])

if test "$PHP_SOCKETS" != "no"; then
AC_CHECK_FUNCS([hstrerror if_nametoindex if_indextoname sockatmark])
AC_CHECK_FUNCS([hstrerror if_nametoindex if_indextoname sockatmark accept4])
AC_CHECK_HEADERS([sys/sockio.h linux/filter.h linux/if_packet.h linux/if_ether.h linux/udp.h])
AC_DEFINE([HAVE_SOCKETS], [1],
[Define to 1 if the PHP extension 'sockets' is available.])
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16 changes: 15 additions & 1 deletion ext/sockets/sockets.c
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Expand Up @@ -283,6 +283,19 @@ static bool php_open_listen_sock(php_socket *sock, unsigned short port, int back

static bool php_accept_connect(php_socket *in_sock, php_socket *out_sock, struct sockaddr *la, socklen_t *la_len) /* {{{ */
{
#if defined(HAVE_ACCEPT4)
int flags = SOCK_CLOEXEC;
if (!in_sock->blocking) {
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@nielsdos nielsdos Jul 27, 2025 •
edited
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Turns out it's even more complicated:

From https://linux.die.net/man/2/accept4:
On Linux, the new socket returned by accept() does not inherit file status flags such as O_NONBLOCK and O_ASYNC from the listening socket. This behavior differs from the canonical BSD sockets implementation. Portable programs should not rely on inheritance or noninheritance of file status flags and always explicitly set all required flags on the socket returned from accept().

So I guess on BSD you have to inherit the flag and on Linux not, in order to remain consistent?

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@devnexen devnexen Jul 27, 2025 •
edited
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we do not create sockets with O_ASYNC in the extension. However it seems to me it s better to set SOCK_NONBLOCK for all platforms

for cross-platform and explicit control, it is always best practice to use accept4() and include the SOCK_NONBLOCK flag if you require a non-blocking socket

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I guess that makes sense. Damn why are the C interfaces always so inconsistent

flags |= SOCK_NONBLOCK;
}

out_sock->bsd_socket = accept4(in_sock->bsd_socket, la, la_len, flags);

if (IS_INVALID_SOCKET(out_sock)) {
PHP_SOCKET_ERROR(out_sock, "unable to accept incoming connection", errno);
return 0;
}
#else
out_sock->bsd_socket = accept(in_sock->bsd_socket, la, la_len);

if (IS_INVALID_SOCKET(out_sock)) {
Expand All @@ -292,7 +305,7 @@ static bool php_accept_connect(php_socket *in_sock, php_socket *out_sock, struct

#if !defined(PHP_WIN32)
/**
* accept4 could had been used but not all platforms support it (e.g. Haiku, solaris < 11.4, ...)
* for fewer and fewer platforms not supporting accept4 syscall we use fcntl instead,
* win32, not having any concept of child process, has no need to address it.
*/
int mode;
Expand All @@ -310,6 +323,7 @@ static bool php_accept_connect(php_socket *in_sock, php_socket *out_sock, struct
return 0;
}
}
#endif
#endif

out_sock->error = 0;
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