core: Add a limited version of gpgrt_ftruncate.

* src/gpg-error.h.in (gpgrt_ftruncate, es_ftruncate): New.
* src/gpg-error.def.in, src/gpg-error.vers: Add gpgrt_ftruncate.
* src/visibility.c (gpgrt_ftruncate): new.
* src/gpgrt-int.h (COOKIE_IOCTL_TRUNCATE): New.
* src/estream.c (func_mem_ioctl): Support new internal IOCTL.
(_gpgrt_ftruncate): New.
--

Right now the ftruncate works only on memory streams.  Can easily be
added to other stream times.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/estream.c b/src/estream.c
index 8ad664e..72e93e0 100644
--- a/src/estream.c
+++ b/src/estream.c
@@ -820,6 +820,14 @@ func_mem_ioctl (void *cookie, int cmd, void *ptr, size_t *len)
       mem_cookie->offset = 0;
       ret = 0;
     }
+  else if (cmd == COOKIE_IOCTL_TRUNCATE)
+    {
+      gpgrt_off_t length = *(gpgrt_off_t *)ptr;
+
+      ret = func_mem_seek (cookie, &length, SEEK_SET);
+      if (ret != -1)
+        mem_cookie->data_len = mem_cookie->offset;
+    }
   else
     {
       _set_errno (EINVAL);
@@ -4027,6 +4035,29 @@ _gpgrt_rewind (estream_t stream)
 
 
 int
+_gpgrt_ftruncate (estream_t stream, gpgrt_off_t length)
+{
+  cookie_ioctl_function_t func_ioctl;
+  int ret;
+
+  lock_stream (stream);
+  func_ioctl = stream->intern->func_ioctl;
+  if (!func_ioctl)
+    {
+      _set_errno (EOPNOTSUPP);
+      ret = -1;
+    }
+  else
+    {
+      ret = func_ioctl (stream->intern->cookie, COOKIE_IOCTL_TRUNCATE,
+                        &length, NULL);
+    }
+  unlock_stream (stream);
+  return ret;
+}
+
+
+int
 _gpgrt__getc_underflow (estream_t stream)
 {
   int err;