get/setsockopt: add fallback for new time64 SO_RCVTIMEO/SO_SNDTIMEO

without this, the SO_RCVTIMEO and SO_SNDTIMEO socket options would
stop working on pre-5.1 kernels after time_t is switched to 64-bit and
their values are changed to the new time64 versions.

new code is written such that it's statically unreachable on 64-bit
archs, and on existing 32-bit archs until the macro values are changed
to activate 64-bit time_t.

1 files changed, 31 insertions, 1 deletions

diff --git a/src/network/setsockopt.c b/src/network/setsockopt.c
index c960c9ca..2c188a96 100644
--- a/src/network/setsockopt.c
+++ b/src/network/setsockopt.c
@@ -1,7 +1,37 @@
 #include <sys/socket.h>
+#include <sys/time.h>
+#include <errno.h>
 #include "syscall.h"
 
+#define IS32BIT(x) !((x)+0x80000000ULL>>32)
+#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
+
 int setsockopt(int fd, int level, int optname, const void *optval, socklen_t optlen)
 {
-	return socketcall(setsockopt, fd, level, optname, optval, optlen, 0);
+	const struct timeval *tv;
+	time_t s;
+	suseconds_t us;
+
+	int r = __socketcall(setsockopt, fd, level, optname, optval, optlen, 0);
+
+	if (r==-ENOPROTOOPT) switch (level) {
+	case SOL_SOCKET:
+		switch (optname) {
+		case SO_RCVTIMEO:
+		case SO_SNDTIMEO:
+			if (SO_RCVTIMEO == SO_RCVTIMEO_OLD) break;
+			if (optlen < sizeof *tv) return __syscall_ret(-EINVAL);
+			tv = optval;
+			s = tv->tv_sec;
+			us = tv->tv_usec;
+			if (!IS32BIT(s)) return __syscall_ret(-ENOTSUP);
+
+			if (optname==SO_RCVTIMEO) optname=SO_RCVTIMEO_OLD;
+			if (optname==SO_SNDTIMEO) optname=SO_SNDTIMEO_OLD;
+
+			r = __socketcall(setsockopt, fd, level, optname,
+				((long[]){s, CLAMP(us)}), 2*sizeof(long), 0);
+		}
+	}
+	return __syscall_ret(r);
 }