[PATCH 3/5] linux-user: Properly handle sigset arg to pselect

[Richard Henderson <richard.henderson@linaro.org>]

Unblocked signals are never delivered, because we
didn't record the new mask for process_pending_signals.
Handle this with the same mechanism as sigsuspend.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/834
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall.c | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 154cb1c7e8..8071a5191d 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1391,14 +1391,12 @@ static abi_long do_pselect6(abi_long arg1, abi_long arg2, abi_long arg3,
      * The 6th arg is actually two args smashed together,
      * so we cannot use the C library.
      */
-    sigset_t set;
     struct {
         sigset_t *set;
         size_t size;
     } sig, *sig_ptr;
 
     abi_ulong arg_sigset, arg_sigsize, *arg7;
-    target_sigset_t *target_sigset;
 
     n = arg1;
     rfd_addr = arg2;
@@ -1439,10 +1437,8 @@ static abi_long do_pselect6(abi_long arg1, abi_long arg2, abi_long arg3,
     }
 
     /* Extract the two packed args for the sigset */
+    sig_ptr = NULL;
     if (arg6) {
-        sig_ptr = &sig;
-        sig.size = SIGSET_T_SIZE;
-
         arg7 = lock_user(VERIFY_READ, arg6, sizeof(*arg7) * 2, 1);
         if (!arg7) {
             return -TARGET_EFAULT;
@@ -1452,28 +1448,22 @@ static abi_long do_pselect6(abi_long arg1, abi_long arg2, abi_long arg3,
         unlock_user(arg7, arg6, 0);
 
         if (arg_sigset) {
-            sig.set = &set;
-            if (arg_sigsize != sizeof(*target_sigset)) {
-                /* Like the kernel, we enforce correct size sigsets */
-                return -TARGET_EINVAL;
+            ret = process_sigsuspend_mask(&sig.set, arg_sigset, arg_sigsize);
+            if (ret != 0) {
+                return ret;
             }
-            target_sigset = lock_user(VERIFY_READ, arg_sigset,
-                                      sizeof(*target_sigset), 1);
-            if (!target_sigset) {
-                return -TARGET_EFAULT;
-            }
-            target_to_host_sigset(&set, target_sigset);
-            unlock_user(target_sigset, arg_sigset, 0);
-        } else {
-            sig.set = NULL;
+            sig_ptr = &sig;
+            sig.size = SIGSET_T_SIZE;
         }
-    } else {
-        sig_ptr = NULL;
     }
 
     ret = get_errno(safe_pselect6(n, rfds_ptr, wfds_ptr, efds_ptr,
                                   ts_ptr, sig_ptr));
 
+    if (sig_ptr) {
+        finish_sigsuspend_mask(ret);
+    }
+
     if (!is_error(ret)) {
         if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n)) {
             return -TARGET_EFAULT;
-- 
2.25.1