compat: generic compat get/settimeofday

Nothing arch specific in get/settimeofday.  The details of the timeval
conversion varied a little from arch to arch, but all with the same
results.

Also add an extern declaration for sys_tz to linux/time.h because externs
in .c files are fowned upon.  I'll kill the externs in various other files
in a sparate patch.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net> [ sparc bits ]
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/kernel/compat.c b/kernel/compat.c
index 32c254a8ab9a..143990e48cb9 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -26,6 +26,64 @@
 
 #include <asm/uaccess.h>
 
+/*
+ * Note that the native side is already converted to a timespec, because
+ * that's what we want anyway.
+ */
+static int compat_get_timeval(struct timespec *o,
+                struct compat_timeval __user *i)
+{
+        long usec;
+
+        if (get_user(o->tv_sec, &i->tv_sec) ||
+            get_user(usec, &i->tv_usec))
+                return -EFAULT;
+        o->tv_nsec = usec * 1000;
+        return 0;
+}
+
+static int compat_put_timeval(struct compat_timeval __user *o,
+                struct timeval *i)
+{
+        return (put_user(i->tv_sec, &o->tv_sec) ||
+                put_user(i->tv_usec, &o->tv_usec)) ? -EFAULT : 0;
+}
+
+asmlinkage long compat_sys_gettimeofday(struct compat_timeval __user *tv,
+                struct timezone __user *tz)
+{
+        if (tv) {
+                struct timeval ktv;
+                do_gettimeofday(&ktv);
+                if (compat_put_timeval(tv, &ktv))
+                        return -EFAULT;
+        }
+        if (tz) {
+                if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
+                        return -EFAULT;
+        }
+
+        return 0;
+}
+
+asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
+                struct timezone __user *tz)
+{
+        struct timespec kts;
+        struct timezone ktz;
+
+        if (tv) {
+                if (compat_get_timeval(&kts, tv))
+                        return -EFAULT;
+        }
+        if (tz) {
+                if (copy_from_user(&ktz, tz, sizeof(ktz)))
+                        return -EFAULT;
+        }
+
+        return do_sys_settimeofday(tv ? &kts : NULL, tz ? &ktz : NULL);
+}
+
 int get_compat_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
 {
         return (!access_ok(VERIFY_READ, cts, sizeof(*cts)) ||