From: Mike Frysinger <vapier@gentoo.org>
Date: Thu, 2 Jun 2016 15:07:42 +0000 (-0400)
Subject: ddnuke: handle final write better, fix initial seek, and improve help
X-Git-Url: https://git.wh0rd.org/?a=commitdiff_plain;h=64f2ae36a6d0138fa8dd651bdc9555bd86fc1d0b;p=home.git

ddnuke: handle final write better, fix initial seek, and improve help
---

diff --git a/ddnuke.c b/ddnuke.c
index 03ac789..8e0abdb 100644
--- a/ddnuke.c
+++ b/ddnuke.c
@@ -73,6 +73,9 @@ static void nuke(int fd, off_t offset, off_t max_size, unsigned char pattern)
 	if (pattern)
 		printf("Writing 0x%X to the output\n", pattern);
 
+	if (lseek(fd, offset, SEEK_SET) != offset)
+		errp("lseek(%"PRIu64"u) failed", offset);
+
 	unsigned long long speed = 0;
 	struct timespec stime, etime, itime;
 	clock_gettime(CLOCK_MONOTONIC, &stime);
@@ -86,15 +89,16 @@ static void nuke(int fd, off_t offset, off_t max_size, unsigned char pattern)
 		ret = write(fd, mem, sizeof(mem));
 		pos += ret;
 		if (ret != sizeof(mem)) {
-			printf("\nread() returned %zi (wanted %zu)\n%'llu MB/s over entire run\n",
-				ret, sizeof(mem), mbps(&itime, &etime, pos));
+			if (pos != max_size)
+				printf("\nread() returned %zi (wanted %zu)\n%'llu MB/s over entire run\n",
+					ret, sizeof(mem), mbps(&itime, &etime, pos));
 			return;
 		}
 
 		printf("%'llu bytes %u%% (%'llu MB/s)%20s\r", (unsigned long long)pos,
 			(unsigned)((pos * 100) / max_size), speed, "");
 
-		if ((++fsync_pos % 16) == 0) {
+		if ((++fsync_pos % 32) == 0) {
 			speed = mbps(&stime, &etime, pos - last_pos);
 			last_pos = pos;
 			fflush(stdout);
@@ -111,9 +115,9 @@ static void usage(int status)
 		status ? stderr : stdout,
 		"Usage: ddnuke [options] <dev>\n"
 		"\n"
-		"Options:"
+		"Options:\n"
 		" -o <offset>   Position to start writing\n"
-		" -r            Write random garbage to the device\n"
+		" -r            Write three times: 0x00, then 0xaa, then 0x55\n"
 	);
 	exit(status);
 }
@@ -149,9 +153,6 @@ int main(int argc, char *argv[])
 
 	off_t max_size = get_size(fd);
 
-	if (lseek(fd, offset, SEEK_SET) != offset)
-		errp("lseek(%"PRIu64"u) failed", offset);
-
 	nuke(fd, offset, max_size, 0x00);
 	if (random) {
 		nuke(fd, offset, max_size, 0xaa);