# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1653252953 -7200
# Node ID a3c858aa56bbf63a18c5ff69928885bf3de8f573
# Parent  0a74c259c65fc3d34c2498d5e12a7d8e52cde996
Introduced memory mapping of the program code from the executable file segment.

diff -r 0a74c259c65f -r a3c858aa56bb libexec/lib/src/segment.cc
--- a/libexec/lib/src/segment.cc	Sun May 22 22:51:57 2022 +0200
+++ b/libexec/lib/src/segment.cc	Sun May 22 22:55:53 2022 +0200
@@ -58,7 +58,7 @@
 
 offset_t Segment::size()
 {
-  return _size;
+  return _region_size;
 }
 
 /* Allocate a writable region for the segment. */
@@ -73,25 +73,32 @@
 
 long Segment::fill(file_t *file)
 {
-  /* Allocate writable memory to populate. */
+  /* NOTE: This should be replaced by copy-on-write dataspace usage. */
+
+  if (_flags & L4RE_RM_F_W)
+  {
+    long err = allocate();
 
-  long err = ipc_allocate_align(_region_size,
-                                L4RE_RM_F_SEARCH_ADDR | _flags | L4RE_RM_F_W,
-                                L4_PAGESHIFT, (void **) &_buf, &_ds);
+    if (err)
+      return err;
 
-  if (err)
-    return err;
+    client_seek(file, _file_offset - _region_offset, SEEK_SET);
+    offset_t nread = client_read(file, _buf, _region_size);
 
-  /* Align the exposed file contents to the memory mapped region.
-     Since the region is page-aligned, the region offset is introduced to map
-     from an earlier part of the file, if appropriate. */
+    memset(_buf, 0, _region_offset);
+    memset(_buf + _region_offset + _file_contents, 0, _region_size - _region_offset - _file_contents);
 
-  memset(_buf, 0, _region_size);
+    if (nread < _file_contents)
+      return -L4_EIO;
+    else
+      return L4_EOK;
+  }
 
-  client_seek(file, _file_offset, SEEK_SET);
-  offset_t nread = client_read(file, _buf + _region_offset, _file_contents);
+  /* Provide the exposed file contents in a masked memory mapped region. */
 
-  if (nread < _file_contents)
+  _buf = (char *) client_mmap(file, _file_offset - _region_offset, _region_size, 0, _flags);
+
+  if (_buf == NULL)
     return -L4_EIO;
   else
     return L4_EOK;