add SOCK_CLOEXEC fallback for socketpair on old kernels

as usual, this is non-atomic, but better than producing an error or
failing to set the close-on-exec flag at all.

diff --git a/src/network/socketpair.c b/src/network/socketpair.c
index b15f846..f348962 100644 (file)
--- a/src/network/socketpair.c
+++ b/src/network/socketpair.c
@@ -1,7 +1,25 @@
 #include <sys/socket.h>
+#include <fcntl.h>
+#include <errno.h>
 #include "syscall.h"
 
 int socketpair(int domain, int type, int protocol, int fd[2])
 {
-       return socketcall(socketpair, domain, type, protocol, fd, 0, 0);
+       int r = socketcall(socketpair, domain, type, protocol, fd, 0, 0);
+       if (r<0 && (errno==EINVAL || errno==EPROTONOSUPPORT)
+           && (type&(SOCK_CLOEXEC|SOCK_NONBLOCK))) {
+               r = socketcall(socketpair, domain,
+                       type & ~(SOCK_CLOEXEC|SOCK_NONBLOCK),
+                       protocol, fd, 0, 0);
+               if (r < 0) return r;
+               if (type & SOCK_CLOEXEC) {
+                       __syscall(SYS_fcntl, fd[0], F_SETFD, FD_CLOEXEC);
+                       __syscall(SYS_fcntl, fd[1], F_SETFD, FD_CLOEXEC);
+               }
+               if (type & SOCK_NONBLOCK) {
+                       __syscall(SYS_fcntl, fd[0], F_SETFL, O_NONBLOCK);
+                       __syscall(SYS_fcntl, fd[1], F_SETFL, O_NONBLOCK);
+               }
+       }
+       return r;
 }