signal: fill in si_code in prepare_kill_siginfo()

So that do_tkill() can use this helper too. This also simplifies
the next patch.

TODO: perhaps we can kill prepare_kill_siginfo() and change the
callers to use SEND_SIG_NOINFO,  but this needs some changes in
__send_signal_locked() and TP_STORE_SIGINFO().

Reviewed-by: Tycho Andersen <tandersen@netflix.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240209130620.GA8039@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/kernel/signal.c b/kernel/signal.c
index c3fac06937e2800d52fb957e4a263828788aaf2d..1450689302d90e42f4652273b6f5e85e241e0cf6 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3793,12 +3793,13 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
 #endif
 #endif
 
-static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
+static void prepare_kill_siginfo(int sig, struct kernel_siginfo *info,
+                                enum pid_type type)
 {
        clear_siginfo(info);
        info->si_signo = sig;
        info->si_errno = 0;
-       info->si_code = SI_USER;
+       info->si_code = (type == PIDTYPE_PID) ? SI_TKILL : SI_USER;
        info->si_pid = task_tgid_vnr(current);
        info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
 }
@@ -3812,7 +3813,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 {
        struct kernel_siginfo info;
 
-       prepare_kill_siginfo(sig, &info);
+       prepare_kill_siginfo(sig, &info, PIDTYPE_TGID);
 
        return kill_something_info(sig, &info, pid);
 }
@@ -3925,7 +3926,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
                    (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
                        goto err;
        } else {
-               prepare_kill_siginfo(sig, &kinfo);
+               prepare_kill_siginfo(sig, &kinfo, PIDTYPE_TGID);
        }
 
        /* TODO: respect PIDFD_THREAD */
@@ -3970,12 +3971,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
 {
        struct kernel_siginfo info;
 
-       clear_siginfo(&info);
-       info.si_signo = sig;
-       info.si_errno = 0;
-       info.si_code = SI_TKILL;
-       info.si_pid = task_tgid_vnr(current);
-       info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+       prepare_kill_siginfo(sig, &info, PIDTYPE_PID);
 
        return do_send_specific(tgid, pid, sig, &info);
 }