ctf-reader: add support to looks for debug information to extract kABI

With this patch, the abidiff tool is now able to looks for CTF debug
information to extract the kABI, it uses the standard
`--debug-info-dir' option to locate `vmlinux.ctfa`, looking at first
instance in the base directory where the ELF binary (vmlinux/module)
is want to be processed.

	* src/abg-ctf-reader.cc (find_ctfa_file): Add new function
	meant to locate the Linux Kernel debug information file
	`vmlinux.ctfa'.
	(ctf_reader::read_corpus): Use `find_ctfa_file' function.

Signed-off-by: Guillermo E. Martinez <guillermo.e.martinez@oracle.com>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>

diff --git a/src/abg-ctf-reader.cc b/src/abg-ctf-reader.cc
index 77e77d138a75d9bcb250cbbd3ddc997ab9c368cb..c1ea15aac63105a6f56da292e17fdf574d030cc9 100644 (file)
--- a/src/abg-ctf-reader.cc
+++ b/src/abg-ctf-reader.cc
@@ -43,6 +43,8 @@ namespace abigail
 namespace ctf_reader
 {
 using std::dynamic_pointer_cast;
+using abigail::tools_utils::dir_name;
+using abigail::tools_utils::file_exists;
 
 class read_context
 {
@@ -1515,6 +1517,42 @@ slurp_elf_info(read_context *ctxt,
   status |= elf_reader::STATUS_OK;
 }
 
+/// Looks for vmlinux.ctfa file in default directory or in
+/// directories provided by debug-info-dir command line option,
+/// it stores location path in @ref ctfa_file.
+///
+/// @param ctxt the read context.
+/// @param ctfa_file file name found.
+/// @return true if file is found.
+static bool
+find_ctfa_file(read_context *ctxt, std::string& ctfa_file)
+{
+  std::string ctfa_dirname;
+  dir_name(ctxt->filename, ctfa_dirname, false);
+
+  // In corpus group we assume vmlinux as first file to
+  // be processed, so default location for vmlinux.cfa
+  // is vmlinux dirname.
+  ctfa_file = ctfa_dirname + "/vmlinux.ctfa";
+  if (file_exists(ctfa_file))
+    return true;
+
+  // If it's proccessing a module, then location directory
+  // for vmlinux.ctfa should be provided with --debug-info-dir
+  // option.
+  for (vector<char**>::const_iterator i = ctxt->debug_info_root_paths_.begin();
+       i != ctxt->debug_info_root_paths_.end();
+       ++i)
+    {
+      ctfa_dirname = **i;
+      ctfa_file = ctfa_dirname + "/vmlinux.ctfa";
+      if (file_exists(ctfa_file))
+        return true;
+    }
+
+  return false;
+}
+
 /// Create and return a new read context to process CTF information
 /// from a given ELF file.
 ///
@@ -1577,12 +1615,11 @@ read_corpus(read_context *ctxt, elf_reader::status &status)
   int errp;
   if (corp->get_origin() & corpus::LINUX_KERNEL_BINARY_ORIGIN)
     {
-      std::string filename;
-      if (tools_utils::base_name(ctxt->filename, filename)
-          && filename == "vmlinux")
+      if (ctxt->ctfa == NULL)
         {
-          std::string vmlinux_ctfa_path = ctxt->filename + ".ctfa";
-          ctxt->ctfa = ctf_arc_open(vmlinux_ctfa_path.c_str(), &errp);
+          std::string ctfa_filename;
+          if (find_ctfa_file(ctxt, ctfa_filename))
+            ctxt->ctfa = ctf_arc_open(ctfa_filename.c_str(), &errp);
         }
     }
   else