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.

arch/mips/syscall_arch.h

@@ -141,3 +141,6 @@ static inline long __syscall7(long n, long a, long b, long c, long d, long e, lo
 #define VDSO_USEFUL
 #define VDSO_CGT_SYM "__vdso_clock_gettime"
 #define VDSO_CGT_VER "LINUX_2.6"
+
+#define SO_SNDTIMEO_OLD 0x1005
+#define SO_RCVTIMEO_OLD 0x1006

arch/mips64/syscall_arch.h

@@ -117,3 +117,6 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 #define VDSO_USEFUL
 #define VDSO_CGT_SYM "__vdso_clock_gettime"
 #define VDSO_CGT_VER "LINUX_2.6"
+
+#define SO_SNDTIMEO_OLD 0x1005
+#define SO_RCVTIMEO_OLD 0x1006

arch/mipsn32/syscall_arch.h

@@ -112,3 +112,6 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 #define VDSO_USEFUL
 #define VDSO_CGT_SYM "__vdso_clock_gettime"
 #define VDSO_CGT_VER "LINUX_2.6"
+
+#define SO_SNDTIMEO_OLD 0x1005
+#define SO_RCVTIMEO_OLD 0x1006

arch/powerpc/syscall_arch.h

@@ -89,3 +89,6 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 }
 
 #define SYSCALL_FADVISE_6_ARG
+
+#define SO_RCVTIMEO_OLD  18
+#define SO_SNDTIMEO_OLD  19

arch/powerpc64/syscall_arch.h

@@ -85,3 +85,6 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 	:: "memory", "cr0", "r9", "r10", "r11", "r12");
 	return r3;
 }
+
+#define SO_RCVTIMEO_OLD  18
+#define SO_SNDTIMEO_OLD  19

src/internal/syscall.h

@@ -299,6 +299,13 @@ hidden long __syscall_ret(unsigned long),
 #define __SC_recvmmsg    19
 #define __SC_sendmmsg    20
 
+#ifndef SO_RCVTIMEO_OLD
+#define SO_RCVTIMEO_OLD  20
+#endif
+#ifndef SO_SNDTIMEO_OLD
+#define SO_SNDTIMEO_OLD  21
+#endif
+
 #ifdef SYS_open
 #define __sys_open2(x,pn,fl) __syscall2(SYS_open, pn, (fl)|O_LARGEFILE)
 #define __sys_open3(x,pn,fl,mo) __syscall3(SYS_open, pn, (fl)|O_LARGEFILE, mo)

src/network/getsockopt.c

 #include <sys/socket.h>
+#include <sys/time.h>
+#include <errno.h>
 #include "syscall.h"
 
 int getsockopt(int fd, int level, int optname, void *restrict optval, socklen_t *restrict optlen)
 {
-	return socketcall(getsockopt, fd, level, optname, optval, optlen, 0);
+	long tv32[2];
+	struct timeval *tv;
+
+	int r = __socketcall(getsockopt, 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);
+			if (optname==SO_RCVTIMEO) optname=SO_RCVTIMEO_OLD;
+			if (optname==SO_SNDTIMEO) optname=SO_SNDTIMEO_OLD;
+			r = __socketcall(getsockopt, fd, level, optname,
+				tv32, (socklen_t[]){sizeof tv32}, 0);
+			if (r<0) break;
+			tv = optval;
+			tv->tv_sec = tv32[0];
+			tv->tv_usec = tv32[1];
+			*optlen = sizeof *tv;
+		}
+	}
+	return __syscall_ret(r);
 }

src/network/setsockopt.c

 #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);
 }