libdwfl automagic decompression support

1 files changed, 143 insertions, 0 deletions

diff --git a/libdwfl/open.c b/libdwfl/open.c
new file mode 100644
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--- /dev/null
+++ b/libdwfl/open.c
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+/* Decompression support for libdwfl: zlib (gzip) and/or bzlib (bzip2).
+   Copyright (C) 2009 Red Hat, Inc.
+   This file is part of Red Hat elfutils.
+
+   Red Hat elfutils is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by the
+   Free Software Foundation; version 2 of the License.
+
+   Red Hat elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with Red Hat elfutils; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
+
+   In addition, as a special exception, Red Hat, Inc. gives You the
+   additional right to link the code of Red Hat elfutils with code licensed
+   under any Open Source Initiative certified open source license
+   (http://www.opensource.org/licenses/index.php) which requires the
+   distribution of source code with any binary distribution and to
+   distribute linked combinations of the two.  Non-GPL Code permitted under
+   this exception must only link to the code of Red Hat elfutils through
+   those well defined interfaces identified in the file named EXCEPTION
+   found in the source code files (the "Approved Interfaces").  The files
+   of Non-GPL Code may instantiate templates or use macros or inline
+   functions from the Approved Interfaces without causing the resulting
+   work to be covered by the GNU General Public License.  Only Red Hat,
+   Inc. may make changes or additions to the list of Approved Interfaces.
+   Red Hat's grant of this exception is conditioned upon your not adding
+   any new exceptions.  If you wish to add a new Approved Interface or
+   exception, please contact Red Hat.  You must obey the GNU General Public
+   License in all respects for all of the Red Hat elfutils code and other
+   code used in conjunction with Red Hat elfutils except the Non-GPL Code
+   covered by this exception.  If you modify this file, you may extend this
+   exception to your version of the file, but you are not obligated to do
+   so.  If you do not wish to provide this exception without modification,
+   you must delete this exception statement from your version and license
+   this file solely under the GPL without exception.
+
+   Red Hat elfutils is an included package of the Open Invention Network.
+   An included package of the Open Invention Network is a package for which
+   Open Invention Network licensees cross-license their patents.  No patent
+   license is granted, either expressly or impliedly, by designation as an
+   included package.  Should you wish to participate in the Open Invention
+   Network licensing program, please visit www.openinventionnetwork.com
+   <http://www.openinventionnetwork.com>.  */
+
+#include "../libelf/libelfP.h"
+#undef	_
+#include "libdwflP.h"
+
+#include <unistd.h>
+
+#if !USE_ZLIB
+# define __libdw_gunzip(...)	false
+#endif
+
+#if !USE_BZLIB
+# define __libdw_bunzip2(...)	false
+#endif
+
+/* Always consumes *ELF, never consumes FD.
+   Replaces *ELF on success.  */
+static Dwfl_Error
+decompress (int fd, Elf **elf)
+{
+  Dwfl_Error error = DWFL_E_BADELF;
+
+#if USE_ZLIB || USE_BZLIB
+  void *buffer;
+  size_t size;
+
+  const off64_t offset = (*elf)->start_offset;
+  void *const mapped = ((*elf)->map_address == NULL ? NULL
+			: (*elf)->map_address + (*elf)->start_offset);
+  const size_t mapped_size = (*elf)->maximum_size;
+
+  error = __libdw_gunzip (fd, offset, mapped, mapped_size, &buffer, &size);
+  if (error == DWFL_E_BADELF)
+    error = __libdw_bunzip2 (fd, offset, mapped, mapped_size, &buffer, &size);
+#endif
+
+  elf_end (*elf);
+  *elf = NULL;
+
+  if (error == DWFL_E_NOERROR)
+    {
+      *elf = elf_memory (buffer, size);
+      if (*elf == NULL)
+	{
+	  error = DWFL_E_LIBELF;
+	  free (buffer);
+	}
+      else
+	(*elf)->flags |= ELF_F_MALLOCED;
+    }
+
+  return error;
+}
+
+Dwfl_Error internal_function
+__libdw_open_file (int *fdp, Elf **elfp, bool close_on_fail, bool archive_ok)
+{
+  bool close_fd = false;
+  Dwfl_Error error = DWFL_E_NOERROR;
+
+  Elf *elf = elf_begin (*fdp, ELF_C_READ_MMAP_PRIVATE, NULL);
+  Elf_Kind kind = elf_kind (elf);
+  if (unlikely (kind == ELF_K_NONE))
+    {
+      if (unlikely (elf == NULL))
+	error = DWFL_E_LIBELF;
+      else
+	{
+	  error = decompress (*fdp, &elf);
+	  if (error == DWFL_E_NOERROR)
+	    {
+	      close_fd = true;
+	      kind = elf_kind (elf);
+	    }
+	}
+    }
+
+  if (error == DWFL_E_NOERROR
+      && kind != ELF_K_ELF
+      && !(archive_ok && kind == ELF_K_AR))
+    {
+      elf_end (elf);
+      elf = NULL;
+      error = DWFL_E_BADELF;
+    }
+
+  if (error == DWFL_E_NOERROR ? close_fd : close_on_fail)
+    {
+      close (*fdp);
+      *fdp = -1;
+    }
+
+  *elfp = elf;
+  return error;
+}