y2038: signal: Add sys_rt_sigtimedwait_time32

Once sys_rt_sigtimedwait() gets changed to a 64-bit time_t, we have
to provide compatibility support for existing binaries.

An earlier version of this patch reused the compat_sys_rt_sigtimedwait
entry point to avoid code duplication, but this newer approach
duplicates the existing native entry point instead, which seems
a bit cleaner.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 03cda6793be3f63fae1d0e82b9d6bcd5ccbd882d..251979d2e70919ca7bc80e7204617e70201213ef 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -649,6 +649,10 @@ asmlinkage long sys_rt_sigtimedwait(const sigset_t __user *uthese,
                                siginfo_t __user *uinfo,
                                const struct __kernel_timespec __user *uts,
                                size_t sigsetsize);
+asmlinkage long sys_rt_sigtimedwait_time32(const sigset_t __user *uthese,
+                               siginfo_t __user *uinfo,
+                               const struct old_timespec32 __user *uts,
+                               size_t sigsetsize);
 asmlinkage long sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo);
 
 /* kernel/sys.c */

diff --git a/kernel/signal.c b/kernel/signal.c
index 3c8ea7a328e0d8ada03b2eee1a144b4b1ab291a3..be6744cd0a11b7d464600eec04095a0698d8e63a 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3332,6 +3332,39 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
        return ret;
 }
 
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
+               siginfo_t __user *, uinfo,
+               const struct old_timespec32 __user *, uts,
+               size_t, sigsetsize)
+{
+       sigset_t these;
+       struct timespec64 ts;
+       kernel_siginfo_t info;
+       int ret;
+
+       if (sigsetsize != sizeof(sigset_t))
+               return -EINVAL;
+
+       if (copy_from_user(&these, uthese, sizeof(these)))
+               return -EFAULT;
+
+       if (uts) {
+               if (get_old_timespec32(&ts, uts))
+                       return -EFAULT;
+       }
+
+       ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
+
+       if (ret > 0 && uinfo) {
+               if (copy_siginfo_to_user(uinfo, &info))
+                       ret = -EFAULT;
+       }
+
+       return ret;
+}
+#endif
+
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
                struct compat_siginfo __user *, uinfo,