git: fbc0c2a21b76 - stable/13 - dumpon: proceed without compression if the kernel lacks support

The branch stable/13 has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=fbc0c2a21b761f676050e8769ef6ea498c0ac579

commit fbc0c2a21b761f676050e8769ef6ea498c0ac579
Author:     Ed Maste <emaste@FreeBSD.org>
AuthorDate: 2022-03-10 18:04:34 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2022-04-10 23:12:30 +0000

    dumpon: proceed without compression if the kernel lacks support
    
    PR:             252554
    Reviewed by:    markj
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D34520
    
    (cherry picked from commit 2b20327ec9394754c0bac2d83567b972a08e3930)
---
 sbin/dumpon/dumpon.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/sbin/dumpon/dumpon.c b/sbin/dumpon/dumpon.c
index 2b710a611af3..e7f1d06ea666 100644
--- a/sbin/dumpon/dumpon.c
+++ b/sbin/dumpon/dumpon.c
@@ -572,6 +572,15 @@ main(int argc, char *argv[])
 	error = ioctl(fd, DIOCSKERNELDUMP, kdap);
 	if (error != 0)
 		error = errno;
+	if (error == EINVAL && (gzip || zstd)) {
+		/* Retry without compression in case kernel lacks support. */
+		kdap->kda_compression = KERNELDUMP_COMP_NONE;
+		error = ioctl(fd, DIOCSKERNELDUMP, kdap);
+		if (error == 0)
+			warnx("Compression disabled; kernel may lack gzip or zstd support.");
+		else
+			error = errno;
+	}
 	explicit_bzero(kdap->kda_encryptedkey, kdap->kda_encryptedkeysize);
 	free(kdap->kda_encryptedkey);
 	explicit_bzero(kdap, sizeof(*kdap));