Make dd's signal handler async safe.

PR:		bin/75258
Submitted by:	"Oleg V. Nauman" <oleg@reis.zp.ua>
Arrival Date:	Sun Dec 19 14:50:21 GMT 2004
Reviewed by:	mjg, jhb
Reviewed by:	jilles (earlier version)
MFC after:	1 week

1 files changed, 10 insertions, 18 deletions

diff --git a/bin/dd/misc.c b/bin/dd/misc.c
index 8edc5a5..84cc5ee 100644
--- a/bin/dd/misc.c
+++ b/bin/dd/misc.c
@@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
 
 #include <errno.h>
 #include <inttypes.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -57,41 +58,32 @@ summary(void)
 {
 	struct timeval tv;
 	double secs;
-	char buf[100];
 
 	(void)gettimeofday(&tv, NULL);
 	secs = tv.tv_sec + tv.tv_usec * 1e-6 - st.start;
 	if (secs < 1e-6)
 		secs = 1e-6;
-	/* Use snprintf(3) so that we don't reenter stdio(3). */
-	(void)snprintf(buf, sizeof(buf),
+	(void)fprintf(stderr,
 	    "%ju+%ju records in\n%ju+%ju records out\n",
 	    st.in_full, st.in_part, st.out_full, st.out_part);
-	(void)write(STDERR_FILENO, buf, strlen(buf));
-	if (st.swab) {
-		(void)snprintf(buf, sizeof(buf), "%ju odd length swab %s\n",
+	if (st.swab)
+		(void)fprintf(stderr, "%ju odd length swab %s\n",
 		     st.swab, (st.swab == 1) ? "block" : "blocks");
-		(void)write(STDERR_FILENO, buf, strlen(buf));
-	}
-	if (st.trunc) {
-		(void)snprintf(buf, sizeof(buf), "%ju truncated %s\n",
+	if (st.trunc)
+		(void)fprintf(stderr, "%ju truncated %s\n",
 		     st.trunc, (st.trunc == 1) ? "block" : "blocks");
-		(void)write(STDERR_FILENO, buf, strlen(buf));
-	}
-	(void)snprintf(buf, sizeof(buf),
+	(void)fprintf(stderr,
 	    "%ju bytes transferred in %.6f secs (%.0f bytes/sec)\n",
 	    st.bytes, secs, st.bytes / secs);
-	(void)write(STDERR_FILENO, buf, strlen(buf));
+	need_summary = 0;
 }
 
 /* ARGSUSED */
 void
-summaryx(int notused __unused)
+siginfo_handler(int signo __unused)
 {
-	int save_errno = errno;
 
-	summary();
-	errno = save_errno;
+	need_summary = 1;
 }
 
 /* ARGSUSED */