Fix Joey's report of rename failing across moint points.

[ccan] / tools / tools.c

diff --git a/tools/tools.c b/tools/tools.c
index 87ff4a3b65f4fe9899cf8aebb6e99a40cd244221..18cc1b84cb299fcc8c5659a05b6c6c05da701a82 100644 (file)
--- a/tools/tools.c
+++ b/tools/tools.c
@@ -1,7 +1,10 @@
 #include <ccan/talloc/talloc.h>
 #include <ccan/grab_file/grab_file.h>
+#include <ccan/noerr/noerr.h>
+#include <ccan/read_write_all/read_write_all.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <fcntl.h>
 #include <string.h>
 #include <unistd.h>
 #include <stdarg.h>
@@ -107,3 +110,39 @@ char *temp_file(const void *ctx, const char *extension)
 
        return talloc_asprintf(ctx, "%s/%u%s", tmpdir, count++, extension);
 }
+
+bool move_file(const char *oldname, const char *newname)
+{
+       char *contents;
+       size_t size;
+       int fd;
+       bool ret;
+
+       /* Simple case: rename works. */
+       if (rename(oldname, newname) == 0)
+               return true;
+
+       /* Try copy and delete: not atomic! */
+       contents = grab_file(NULL, oldname, &size);
+       if (!contents)
+               return false;
+
+       fd = open(newname, O_WRONLY|O_CREAT|O_TRUNC, 0666);
+       if (fd < 0) {
+               ret = false;
+               goto free;
+       }
+
+       ret = write_all(fd, contents, size);
+       if (close(fd) != 0)
+               ret = false;
+
+       if (ret)
+               unlink(oldname);
+       else
+               unlink(newname);
+
+free:
+       talloc_free(contents);
+       return ret;
+}