Create read_or_die utility routine.

Like write_or_die read_or_die reads the entire length requested
or it kills the current process with a die call.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/write_or_die.c b/write_or_die.c
index bfe4eeb..8cf6486 100644
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -1,5 +1,21 @@
 #include "cache.h"
 
+void read_or_die(int fd, void *buf, size_t count)
+{
+	char *p = buf;
+	ssize_t loaded;
+
+	while (count > 0) {
+		loaded = xread(fd, p, count);
+		if (loaded == 0)
+			die("unexpected end of file");
+		else if (loaded < 0)
+			die("read error (%s)", strerror(errno));
+		count -= loaded;
+		p += loaded;
+	}
+}
+
 void write_or_die(int fd, const void *buf, size_t count)
 {
 	const char *p = buf;