Pull the file writing code for the wallet client into a separate file

so that the srvtab and keytab management can share it.  Write atomically
to a new file and then link and rename to do an atomic update.  Leave a
backup copy of any file that's replaced.

1 files changed, 7 insertions, 23 deletions

diff --git a/client/internal.h b/client/internal.h
index 834ec57..186d83f 100644
--- a/client/internal.h
+++ b/client/internal.h
@@ -11,29 +11,8 @@
 #ifndef CLIENT_INTERNAL_H
 #define CLIENT_INTERNAL_H 1
 
-/* __attribute__ is available in gcc 2.5 and later, but only with gcc 2.7
-   could you use the __format__ form of the attributes, which is what we use
-   (to avoid confusion with other macros). */
-#ifndef __attribute__
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
-#  define __attribute__(spec)   /* empty */
-# endif
-#endif
-
-/* Used for unused parameters to silence gcc warnings. */
-#define UNUSED  __attribute__((__unused__))
-
-/* BEGIN_DECLS is used at the beginning of declarations so that C++
-   compilers don't mangle their names.  END_DECLS is used at the end. */
-#undef BEGIN_DECLS
-#undef END_DECLS
-#ifdef __cplusplus
-# define BEGIN_DECLS    extern "C" {
-# define END_DECLS      }
-#else
-# define BEGIN_DECLS    /* empty */
-# define END_DECLS      /* empty */
-#endif
+#include <sys/types.h>
+#include <util/util.h>
 
 /* Temporary until we have some real configuration. */
 #ifndef SERVER
@@ -45,6 +24,11 @@
 
 BEGIN_DECLS
 
+/* Given a filename, some data, and a length, write that data to the given
+   file safely and atomically by creating file.new, writing the data, linking
+   file to file.bak, and then renaming file.new to file. */
+void write_file(const char *name, const void *data, size_t length);
+
 /* Given a srvtab file, the Kerberos v5 principal, and the keytab file, write
    a srvtab file for the corresponding Kerberos v4 principal. */
 void write_srvtab(const char *srvtab, const char *principal,