1 files changed, 99 insertions, 0 deletions
diff --git a/src/libdwelf/dwelf_elf_gnu_debuglink.c b/src/libdwelf/dwelf_elf_gnu_debuglink.c
new file mode 100644
index 00000000..6e22cf67
--- /dev/null
+++ b/src/libdwelf/dwelf_elf_gnu_debuglink.c
@@ -0,0 +1,99 @@
+/* Returns the file name and crc stored in the .gnu_debuglink if found.
+   Copyright (C) 2014 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libdwelfP.h"
+
+const char *
+dwelf_elf_gnu_debuglink (Elf *elf, GElf_Word *crc)
+{
+  size_t shstrndx;
+  if (elf_getshdrstrndx (elf, &shstrndx) < 0)
+    return NULL;
+
+  Elf_Scn *scn = NULL;
+  while ((scn = elf_nextscn (elf, scn)) != NULL)
+    {
+      GElf_Shdr shdr_mem;
+      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
+      if (shdr == NULL)
+        return NULL;
+
+      const char *name = elf_strptr (elf, shstrndx, shdr->sh_name);
+      if (name == NULL)
+        return NULL;
+
+      if (!strcmp (name, ".gnu_debuglink"))
+        break;
+    }
+
+  if (scn == NULL)
+    return NULL;
+
+  /* Found the .gnu_debuglink section.  Extract its contents.  */
+  Elf_Data *rawdata = elf_rawdata (scn, NULL);
+  if (rawdata == NULL || rawdata->d_buf == NULL)
+    return NULL;
+
+  /* The CRC comes after the zero-terminated file name,
+     (aligned up to 4 bytes) at the end of the section data.  */
+  if (rawdata->d_size <= sizeof *crc
+      || memchr (rawdata->d_buf, '\0', rawdata->d_size - sizeof *crc) == NULL)
+    return NULL;
+
+  Elf_Data crcdata =
+    {
+      .d_type = ELF_T_WORD,
+      .d_buf = crc,
+      .d_size = sizeof *crc,
+      .d_version = EV_CURRENT,
+    };
+  Elf_Data conv =
+    {
+      .d_type = ELF_T_WORD,
+      .d_buf = rawdata->d_buf + rawdata->d_size - sizeof *crc,
+      .d_size = sizeof *crc,
+      .d_version = EV_CURRENT,
+    };
+
+  GElf_Ehdr ehdr_mem;
+  GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
+  if (ehdr == NULL)
+    return NULL;
+
+  Elf_Data *d = gelf_xlatetom (elf, &crcdata, &conv, ehdr->e_ident[EI_DATA]);
+  if (d == NULL)
+    return NULL;
+  assert (d == &crcdata);
+
+  return rawdata->d_buf;
+}
+INTDEF(dwelf_elf_gnu_debuglink)