ioctl: add fallback for new time64 SIOCGSTAMP[NS]

without this, the SIOCGSTAMP and SIOCGSTAMPNS ioctl commands, for
obtaining timestamps, 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/sh/syscall_arch.h

@@ -88,3 +88,6 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 }
 
 #define SYSCALL_IPC_BROKEN_MODE
+
+#define SIOCGSTAMP_OLD   (2U<<30 | 's'<<8 | 100 | 8<<16)
+#define SIOCGSTAMPNS_OLD (2U<<30 | 's'<<8 | 101 | 8<<16)

src/internal/syscall.h

@@ -306,6 +306,13 @@ hidden long __syscall_ret(unsigned long),
 #define SO_SNDTIMEO_OLD  21
 #endif
 
+#ifndef SIOCGSTAMP_OLD
+#define SIOCGSTAMP_OLD 0x8906
+#endif
+#ifndef SIOCGSTAMPNS_OLD
+#define SIOCGSTAMPNS_OLD 0x8907
+#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/misc/ioctl.c

@@ -1,5 +1,8 @@
 #include <sys/ioctl.h>
 #include <stdarg.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/time.h>
 #include "syscall.h"
 
 int ioctl(int fd, int req, ...)
@@ -9,5 +12,25 @@ int ioctl(int fd, int req, ...)
 	va_start(ap, req);
 	arg = va_arg(ap, void *);
 	va_end(ap);
-	return syscall(SYS_ioctl, fd, req, arg);
+	int r = __syscall(SYS_ioctl, fd, req, arg);
+	if (r==-ENOTTY) switch (req) {
+	case SIOCGSTAMP:
+	case SIOCGSTAMPNS:
+		if (SIOCGSTAMP==SIOCGSTAMP_OLD) break;
+		if (req==SIOCGSTAMP) req=SIOCGSTAMP_OLD;
+		if (req==SIOCGSTAMPNS) req=SIOCGSTAMPNS_OLD;
+		long t32[2];
+		r = __syscall(SYS_ioctl, fd, req, t32);
+		if (r<0) break;
+		if (req==SIOCGSTAMP_OLD) {
+			struct timeval *tv = arg;
+			tv->tv_sec = t32[0];
+			tv->tv_usec = t32[1];
+		} else {
+			struct timespec *ts = arg;
+			ts->tv_sec = t32[0];
+			ts->tv_nsec = t32[1];
+		}
+	}
+	return __syscall_ret(r);
 }