Quell Coverity for diskinfo(8)

* CID 1198994: Don't run the speed disk on a disk with no sectors
* CID 1011442: Don't call close(2) if open(2) fails
* CID 1011161: Use snprintf instead of sprintf
* CID 1009825: Check the return value of lseek

Reported by:	Coverity
CID:		1198994 1011442 1011161 1009825
MFC after:	4 weeks
Sponsored by:	Spectra Logic Corp

1 files changed, 7 insertions, 4 deletions

diff --git a/usr.sbin/diskinfo/diskinfo.c b/usr.sbin/diskinfo/diskinfo.c
index df51aac2691e..438f1b8b9655 100644
--- a/usr.sbin/diskinfo/diskinfo.c
+++ b/usr.sbin/diskinfo/diskinfo.c
@@ -104,13 +104,12 @@ main(int argc, char **argv)
 	for (i = 0; i < argc; i++) {
 		fd = open(argv[i], O_RDONLY | O_DIRECT);
 		if (fd < 0 && errno == ENOENT && *argv[i] != '/') {
-			sprintf(buf, "%s%s", _PATH_DEV, argv[i]);
+			snprintf(buf, BUFSIZ, "%s%s", _PATH_DEV, argv[i]);
 			fd = open(buf, O_RDONLY);
 		}
 		if (fd < 0) {
 			warn("%s", argv[i]);
-			exitval = 1;
-			goto out;
+			exit(1);
 		}
 		error = fstat(fd, &sb);
 		if (error != 0) {
@@ -213,7 +212,8 @@ rdsect(int fd, off_t blockno, u_int sectorsize)
 {
 	int error;
 
-	lseek(fd, (off_t)blockno * sectorsize, SEEK_SET);
+	if (lseek(fd, (off_t)blockno * sectorsize, SEEK_SET) == -1)
+		err(1, "lseek");
 	error = read(fd, sector, sectorsize);
 	if (error == -1)
 		err(1, "read");
@@ -296,6 +296,9 @@ speeddisk(int fd, off_t mediasize, u_int sectorsize)
 	off_t b0, b1, sectorcount, step;
 
 	sectorcount = mediasize / sectorsize;
+	if (sectorcount <= 0)
+		return;		/* Can't test devices with no sectors */
+
 	step = 1ULL << (flsll(sectorcount / (4 * 200)) - 1);
 	if (step > 16384)
 		step = 16384;