burncd(8) doesn't handle signals and interrupting burncd during operation.

For example, ^C (SIGINT) may leave the drive spinning and locked.
This may also happen if you try to write a too-large image to a disc
and burncd(8) exits with an I/O error.

Add signal handling by doing a CDRIOCFLUSH ioctl to attempt to leave
burner in a sane state when burning is interrupted with SIGHUP, SIGINT,
SIGTERM, or in case an I/O error occurs during write.
Note, that blanking will still continue after interrupt but it seems to
finish correctly even after burncd(8) has quit.

Also, while I'm here bump WARNS to "6".

PR:		48730
Submitted by:	Jaakko Heinonen <jh@saunalahti.fi>

2 files changed, 37 insertions, 6 deletions

diff --git a/usr.sbin/burncd/Makefile b/usr.sbin/burncd/Makefile
index 6f03273..bd4f285 100644
--- a/usr.sbin/burncd/Makefile
+++ b/usr.sbin/burncd/Makefile
@@ -3,6 +3,6 @@
 PROG=	burncd
 MAN=	burncd.8
 
-WARNS?=	5
+WARNS?=	6
 
 .include <bsd.prog.mk>
diff --git a/usr.sbin/burncd/burncd.c b/usr.sbin/burncd/burncd.c
index 2800f52..5be73e0f 100644
--- a/usr.sbin/burncd/burncd.c
+++ b/usr.sbin/burncd/burncd.c
@@ -29,6 +29,7 @@
  */
 
 #include <unistd.h>
+#include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -67,6 +68,8 @@ int write_file(int fd, struct track_info *);
 int roundup_blocks(struct track_info *);
 void cue_ent(struct cdr_cue_entry *, int, int, int, int, int, int, int);
 void cleanup(int);
+void cleanup_flush(void);
+void cleanup_signal(int);
 void usage(void);
 
 int
@@ -157,6 +160,9 @@ main(int argc, char **argv)
 
 	global_fd_for_cleanup = fd;
 	err_set_exit(cleanup);
+	signal(SIGHUP, cleanup_signal);
+	signal(SIGINT, cleanup_signal);
+	signal(SIGTERM, cleanup_signal);
 
 	for (arg = 0; arg < argc; arg++) {
 		if (!strcasecmp(argv[arg], "fixate")) {
@@ -319,6 +325,10 @@ main(int argc, char **argv)
 	if (eject)
 		if (ioctl(fd, CDIOCEJECT) < 0)
 			err(EX_IOERR, "ioctl(CDIOCEJECT)");
+
+	signal(SIGHUP, SIG_DFL);
+	signal(SIGINT, SIG_DFL);
+	signal(SIGTERM, SIG_DFL);
 	close(fd);
 	exit(EX_OK);
 }
@@ -469,8 +479,10 @@ do_DAO(int fd, int test_write, int multi)
 		err(EX_IOERR, "ioctl(CDRIOCSENDCUE)");
 
 	for (i = 0; i < notracks; i++) {
-		if (write_file(fd, &tracks[i]))
+		if (write_file(fd, &tracks[i])) {
+			cleanup_flush();
 			err(EX_IOERR, "write_file");
+		}
 	}
 
 	ioctl(fd, CDRIOCFLUSH);
@@ -499,8 +511,10 @@ do_TAO(int fd, int test_write, int preemp, int dvdrw)
 		if (!quiet)
 			fprintf(stderr, "next writeable LBA %d\n",
 				tracks[i].addr);
-		if (write_file(fd, &tracks[i]))
+		if (write_file(fd, &tracks[i])) {
+			cleanup_flush();
 			err(EX_IOERR, "write_file");
+		}
 		if (ioctl(fd, CDRIOCFLUSH) < 0)
 			err(EX_IOERR, "ioctl(CDRIOCFLUSH)");
 	}
@@ -630,9 +644,11 @@ write_file(int fd, struct track_info *track_info)
 				track_info->block_size;
 		}
 		if ((res = write(fd, buf, count)) != count) {
-			if (res == -1)
-				fprintf(stderr, "\n%s\n", strerror(errno));
-			else
+			if (res == -1) {
+				fprintf(stderr, "\n");
+				close(track_info->file);
+				return errno;
+			} else
 				fprintf(stderr, "\nonly wrote %d of %jd"
 				    " bytes\n", res, (intmax_t)count);
 			break;
@@ -693,6 +709,21 @@ cleanup(int dummy __unused)
 }
 
 void
+cleanup_flush(void)
+{
+	if (ioctl(global_fd_for_cleanup, CDRIOCFLUSH) < 0)
+		err(EX_IOERR, "ioctl(CDRIOCFLUSH)");
+}
+
+void
+cleanup_signal(int sig __unused)
+{
+	cleanup_flush();
+	fprintf(stderr, "\n");
+	errx(EXIT_FAILURE, "Aborted");
+}
+
+void
 usage(void)
 {
 	fprintf(stderr,