generic compat_sys_rt_sigprocmask()

conditional on GENERIC_COMPAT_RT_SIGPROCMASK; by the end of that series
it will become the same thing as COMPAT and conditional will die out.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 63 insertions, 2 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 6e4c32a5a358..374a68adbf1f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -359,6 +359,9 @@ config MODULES_USE_ELF_REL
 config GENERIC_SIGALTSTACK
         bool
 
+config GENERIC_COMPAT_RT_SIGPROCMASK
+        bool
+
 #
 # ABI hall of shame
 #
diff --git a/include/linux/compat.h b/include/linux/compat.h
index dec7e2d18875..9d3c2a98d537 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -401,7 +401,8 @@ asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
 asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
 
 extern int compat_printk(const char *fmt, ...);
-extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);
+extern void sigset_from_compat(sigset_t *set, const compat_sigset_t *compat);
+extern void sigset_to_compat(compat_sigset_t *compat, const sigset_t *set);
 
 asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
                 compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
@@ -592,6 +593,11 @@ asmlinkage long compat_sys_rt_sigtimedwait(compat_sigset_t __user *uthese,
                 struct compat_timespec __user *uts, compat_size_t sigsetsize);
 asmlinkage long compat_sys_rt_sigsuspend(compat_sigset_t __user *unewset,
                                          compat_size_t sigsetsize);
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGPROCMASK
+asmlinkage long compat_sys_rt_sigprocmask(int how, compat_sigset_t __user *set,
+                                          compat_sigset_t __user *oset,
+                                          compat_size_t sigsetsize);
+#endif
 asmlinkage long compat_sys_sysinfo(struct compat_sysinfo __user *info);
 asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
                                  unsigned long arg);
diff --git a/kernel/compat.c b/kernel/compat.c
index 0c07d435254f..e2a9c4785988 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -971,7 +971,7 @@ long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 }
 
 void
-sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
+sigset_from_compat(sigset_t *set, const compat_sigset_t *compat)
 {
         switch (_NSIG_WORDS) {
         case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
@@ -982,6 +982,17 @@ sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
 }
 EXPORT_SYMBOL_GPL(sigset_from_compat);
 
+void
+sigset_to_compat(compat_sigset_t *compat, const sigset_t *set)
+{
+        switch (_NSIG_WORDS) {
+        case 4: compat->sig[7] = (set->sig[3] >> 32); compat->sig[6] = set->sig[3];
+        case 3: compat->sig[5] = (set->sig[2] >> 32); compat->sig[4] = set->sig[2];
+        case 2: compat->sig[3] = (set->sig[1] >> 32); compat->sig[2] = set->sig[1];
+        case 1: compat->sig[1] = (set->sig[0] >> 32); compat->sig[0] = set->sig[0];
+        }
+}
+
 asmlinkage long
 compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
                 struct compat_siginfo __user *uinfo,
diff --git a/kernel/signal.c b/kernel/signal.c
index 4a0934e03d5c..bce1222b7315 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2613,6 +2613,47 @@ SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
         return 0;
 }
 
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGPROCMASK
+COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
+                compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
+{
+#ifdef __BIG_ENDIAN
+        sigset_t old_set = current->blocked;
+
+        /* XXX: Don't preclude handling different sized sigset_t's.  */
+        if (sigsetsize != sizeof(sigset_t))
+                return -EINVAL;
+
+        if (nset) {
+                compat_sigset_t new32;
+                sigset_t new_set;
+                int error;
+                if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
+                        return -EFAULT;
+
+                sigset_from_compat(&new_set, &new32);
+                sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+                error = sigprocmask(how, &new_set, NULL);
+                if (error)
+                        return error;
+        }
+        if (oset) {
+                compat_sigset_t old32;
+                sigset_to_compat(&old32, &old_set);
+                if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+                        return -EFAULT;
+        }
+        return 0;
+#else
+        return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
+                                  (sigset_t __user *)oset, sigsetsize);
+#endif
+}
+#endif
+#endif
+
 long do_sigpending(void __user *set, unsigned long sigsetsize)
 {
         long error = -EINVAL;