Add make-sparse.c to contrib

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 79 insertions, 0 deletions

diff --git a/contrib/make-sparse.c b/contrib/make-sparse.c
new file mode 100644
index 00000000..4a7a3155
--- /dev/null
+++ b/contrib/make-sparse.c
@@ -0,0 +1,79 @@
+/*
+ * make-sparse.c --- make a sparse file from stdin
+ * 
+ * Copyright 2004 by Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#define _LARGEFILE_SOURCE
+#define _LARGEFILE64_SOURCE
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int full_read(int fd, char *buf, size_t count)
+{
+	int got, total = 0;
+	int pass = 0;
+
+	while (count > 0) {
+		got = read(fd, buf, count);
+		if (got == -1) {
+			if ((errno == EINTR) || (errno == EAGAIN)) 
+				continue;
+			return total ? total : -1;
+		}
+		if (got == 0) {
+			if (pass++ >= 3)
+				return total;
+			continue;
+		}
+		pass = 0;
+		buf += got;
+		total += got;
+		count -= got;
+	}
+	return total;
+}
+
+int main(int argc, char **argv)
+{
+	int fd, got, i;
+	char buf[1024];
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: make-sparse out-file\n");
+		exit(1);
+	}
+	fd = open(argv[1], O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0777);
+	if (fd < 0) {
+		perror(argv[1]);
+		exit(1);
+	}
+	while (1) {
+		got = full_read(0, buf, sizeof(buf));
+		if (got == 0)
+			break;
+		if (got == sizeof(buf)) {
+			for (i=0; i < sizeof(buf); i++) 
+				if (buf[i])
+					break;
+			if (i == sizeof(buf)) {
+				lseek(fd, sizeof(buf), SEEK_CUR);
+				continue;
+			}
+		}
+		write(fd, buf, got);
+	}
+	return 0;
+}
+