send pack check for failure to send revisions list

When passing the revisions list to pack-objects we do not check for
errors nor short writes.  Introduce a new write_in_full which will
handle short writes and report errors to the caller.  Use this to
short cut the send on failure, allowing us to wait for and report
the child in case the failure is its fault.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

cache.h

@@ -420,6 +420,7 @@ extern char *git_commit_encoding;
 extern char *git_log_output_encoding;
 
 extern int copy_fd(int ifd, int ofd);
+extern int write_in_full(int fd, const void *buf, size_t count, const char *);
 extern void write_or_die(int fd, const void *buf, size_t count);
 extern int write_or_whine(int fd, const void *buf, size_t count, const char *msg);
 

send-pack.c

@@ -65,12 +65,16 @@ static int pack_objects(int fd, struct ref *refs)
 			memcpy(buf + 1, sha1_to_hex(refs->old_sha1), 40);
 			buf[0] = '^';
 			buf[41] = '\n';
-			write(pipe_fd[1], buf, 42);
+			if (!write_in_full(pipe_fd[1], buf, 42,
+						"send-pack: send refs"))
+				break;
 		}
 		if (!is_null_sha1(refs->new_sha1)) {
 			memcpy(buf, sha1_to_hex(refs->new_sha1), 40);
 			buf[40] = '\n';
-			write(pipe_fd[1], buf, 41);
+			if (!write_in_full(pipe_fd[1], buf, 41,
+						"send-pack: send refs"))
+				break;
 		}
 		refs = refs->next;
 	}

write_or_die.c

@@ -43,3 +43,26 @@ int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
 
 	return 1;
 }
+
+int write_in_full(int fd, const void *buf, size_t count, const char *msg)
+{
+	const char *p = buf;
+	ssize_t written;
+
+	while (count > 0) {
+		written = xwrite(fd, p, count);
+		if (written == 0) {
+			fprintf(stderr, "%s: disk full?\n", msg);
+			return 0;
+		}
+		else if (written < 0) {
+			fprintf(stderr, "%s: write error (%s)\n",
+				msg, strerror(errno));
+			return 0;
+		}
+		count -= written;
+		p += written;
+	}
+
+	return 1;
+}