- Don't assign the return value from read(2) to a variable of type

  int.
- Use errx(3) instead of err(3) to print the error message on short
  reads in readlabel(). errno won't be set on short reads which can
  easily occur here due to the fixed size read request.

PR:		144307
Reviewed by:	bde

1 files changed, 8 insertions, 6 deletions

diff --git a/sbin/bsdlabel/bsdlabel.c b/sbin/bsdlabel/bsdlabel.c
index 7f05874..b34fe75 100644
--- a/sbin/bsdlabel/bsdlabel.c
+++ b/sbin/bsdlabel/bsdlabel.c
@@ -347,7 +347,7 @@ makelabel(const char *type, struct disklabel *lp)
 static void
 readboot(void)
 {
-	int fd, i;
+	int fd;
 	struct stat st;
 	uint64_t *p;
 
@@ -358,8 +358,7 @@ readboot(void)
 		err(1, "cannot open %s", xxboot);
 	fstat(fd, &st);
 	if (alphacksum && st.st_size <= BBSIZE - 512) {
-		i = read(fd, bootarea + 512, st.st_size);
-		if (i != st.st_size)
+		if (read(fd, bootarea + 512, st.st_size) != st.st_size)
 			err(1, "read error %s", xxboot);
 
 		/*
@@ -372,8 +371,7 @@ readboot(void)
 		p[62] = 0;
 		return;
 	} else if ((!alphacksum) && st.st_size <= BBSIZE) {
-		i = read(fd, bootarea, st.st_size);
-		if (i != st.st_size)
+		if (read(fd, bootarea, st.st_size) != st.st_size)
 			err(1, "read error %s", xxboot);
 		return;
 	}
@@ -479,6 +477,7 @@ get_file_parms(int f)
 static int
 readlabel(int flag)
 {
+	ssize_t nbytes;
 	uint32_t lba;
 	int f, i;
 	int error;
@@ -498,8 +497,11 @@ readlabel(int flag)
 		errx(1,
 		    "disks with more than 2^32-1 sectors are not supported");
 	(void)lseek(f, (off_t)0, SEEK_SET);
-	if (read(f, bootarea, BBSIZE) != BBSIZE)
+	nbytes = read(f, bootarea, BBSIZE);
+	if (nbytes == -1)
 		err(4, "%s read", specname);
+	if (nbytes != BBSIZE)
+		errx(4, "couldn't read %d bytes from %s", BBSIZE, specname);
 	close (f);
 	error = bsd_disklabel_le_dec(
 	    bootarea + (labeloffset + labelsoffset * secsize),