git: 6edbe5616c76 - main - Provide some more information for userland core dumps

The branch main has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=6edbe5616c761bff9e570d9c77db0644a9487174

commit 6edbe5616c761bff9e570d9c77db0644a9487174
Author:     Ed Maste <emaste@FreeBSD.org>
AuthorDate: 2017-10-27 14:26:03 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2023-08-05 23:18:35 +0000

    Provide some more information for userland core dumps
    
    Previously the log message indicated only "(core dumped)" if a core was
    successfully created, or nothing if it was not. This provides
    insufficient information to faciliate debugging. Dtrace is no help as
    coredump() is static and we cannot find the return value via fbt.
    Expand the log message to include error return value information.
    
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D39942
---
 sys/kern/kern_sig.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 5876e2e93920..df3ebc0103c4 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -3598,6 +3598,8 @@ void
 sigexit(struct thread *td, int sig)
 {
 	struct proc *p = td->td_proc;
+	const char *coreinfo;
+	int rv;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	proc_set_p2_wexit(p);
@@ -3622,16 +3624,31 @@ sigexit(struct thread *td, int sig)
 		 * XXX : Todo, as well as euid, write out ruid too
 		 * Note that coredump() drops proc lock.
 		 */
-		if (coredump(td) == 0)
+		rv = coredump(td);
+		switch (rv) {
+		case 0:
 			sig |= WCOREFLAG;
+			coreinfo = " (core dumped)";
+			break;
+		case EFAULT:
+			coreinfo = " (no core dump - bad address)";
+			break;
+		case EINVAL:
+			coreinfo = " (no core dump - invalid argument)";
+			break;
+		case EFBIG:
+			coreinfo = " (no core dump - too large)";
+			break;
+		default:
+			coreinfo = " (no core dump - other error)";
+		}
 		if (kern_logsigexit)
 			log(LOG_INFO,
 			    "pid %d (%s), jid %d, uid %d: exited on "
 			    "signal %d%s\n", p->p_pid, p->p_comm,
 			    p->p_ucred->cr_prison->pr_id,
 			    td->td_ucred->cr_uid,
-			    sig &~ WCOREFLAG,
-			    sig & WCOREFLAG ? " (core dumped)" : "");
+			    sig &~ WCOREFLAG, coreinfo);
 	} else
 		PROC_UNLOCK(p);
 	exit1(td, 0, sig);