Adding wallet rekey capability -- work in progress, testing

First, testing version of wallet rekey code, committed in order to get
feedback from Russ.  This code will eventually take an existing keytab
file, and for every principal belonging to our default realm in it, get
new versions of that keytab and merge them into the file.  This allows
for quietly rekeying principals automatically.

1 files changed, 26 insertions, 0 deletions

diff --git a/client/file.c b/client/file.c
index 66d5f63..f24d3ca 100644
--- a/client/file.c
+++ b/client/file.c
@@ -46,6 +46,32 @@ overwrite_file(const char *name, const void *data, size_t length)
         sysdie("close of %s failed (file probably truncated)", name);
 }
 
+/*
+ * Given a filename, some data, and a length, write that data to the given
+ * file safely, but overwrite any existing file by that name.
+ */
+void
+append_file(const char *name, const void *data, size_t length)
+{
+    int fd;
+    ssize_t status;
+
+    if (access(name, F_OK) == 0)
+        if (unlink(name) < 0)
+            sysdie("unable to delete existing file %s", name);
+    fd = open(name, O_WRONLY | O_APPEND);
+    if (fd < 0)
+        sysdie("open of %s failed", name);
+    if (length > 0) {
+        status = write(fd, data, length);
+        if (status < 0)
+            sysdie("write to %s failed", name);
+        else if (status != (ssize_t) length)
+            die("write to %s truncated", name);
+    }
+    if (close(fd) < 0)
+        sysdie("close of %s failed (file probably truncated)", name);
+}
 
 /*
  * Given a filename, some data, and a length, write that data to the given