Add make-sparse.c to contrib

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

diff --git a/contrib/make-sparse.c b/contrib/make-sparse.c
new file mode 100644 (file)
index 0000000..4a7a315
--- /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;
+}
+