Fix up totally buggered read_or_die()

[Linus Torvalds <torvalds@osdl.org>]

The "read_or_die()" function would silently NOT die for a partial read, 
and since it was of type "void" it obviously couldn't even return the 
partial number of bytes read.

IOW, it was totally broken. This hopefully fixes it up.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

I'm really quite fed up with the "cleanups" that were just too buggy for 
words.

diff --git a/write_or_die.c b/write_or_die.c
index 1224cac..4e8183e 100644
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -4,16 +4,11 @@ int read_in_full(int fd, void *buf, size_t count)
 {
 	char *p = buf;
 	ssize_t total = 0;
-	ssize_t loaded = 0;
 
 	while (count > 0) {
-		loaded = xread(fd, p, count);
-		if (loaded <= 0) {
-			if (total)
-				return total;
-			else
-				return loaded;
-		}
+		ssize_t loaded = xread(fd, p, count);
+		if (loaded <= 0)
+			return total ? total : loaded;
 		count -= loaded;
 		p += loaded;
 		total += loaded;
@@ -26,13 +21,12 @@ void read_or_die(int fd, void *buf, size_t count)
 {
 	ssize_t loaded;
 
-	if (!count)
-		return;
 	loaded = read_in_full(fd, buf, count);
-	if (loaded == 0)
-		die("unexpected end of file");
-	else if (loaded < 0)
-		die("read error (%s)", strerror(errno));
+	if (loaded != count) {
+		if (loaded < 0)
+			die("read error (%s)", strerror(errno));
+		die("read error: end of file");
+	}
 }
 
 int write_in_full(int fd, const void *buf, size_t count)