Add support for debuginfod to the binutils (disable by default, enabled via a configure time option).

debuginfod is a lightweight web service that indexes ELF/DWARF
debugging resources by build-id and serves them over HTTP. This patch
enables objdump and readelf to query debuginfod servers when they are
otherwise not able to find separate debug files. Binutils can be built
with debuginfod using the --with-debuginfod configure option. This
requires that libdebuginfod be installed and found at configure time.
debuginfod is packaged with elfutils, starting with version 0.178. For
more information see https://sourceware.org/elfutils/.

toplevel* config/debuginfod.m4: New file. Add macro AC_DEBUGINFOD. Adds
        new configure option --with-debuginfod.
        * configure: Regenerate.
        * configure.ac: Call AC_DEBUGINFOD.

binutils* Makefile.am (readelf_LDADD, objdump_LDADD): Add libdebuginfod.
        * Makefile.in: Regenerate.
        * NEWS: Update.
        * config.in: Regenerate.
        * configure: Regenerate.
        * configure.ac: Call AC_DEBUGINFOD.
        * doc/Makefile.in: Regenerate.
        * doc/binutils.texi: Add section on using binutils
        with debuginfod.
        * dwarf.c (debuginfod_fetch_separate_debug_info): New function.
        Query debuginfod servers for the target debug file.
        (load_separate_debug_info): Call
        debuginfod_fetch_separate_debug_info if configured with
        debuginfod.
        (load_separate_debug_files): Add file argument to
        load_separate_debug_info calls.
        * dwarf.h (get_build_id): Add declaration.
        * objdump.c (get_build_id): New function. Get build-id of file.
        * readelf.c (get_build_id): Likewise.
        * testsuite/binutils-all/debuginfod.exp: New tests.
        * testsuite/binutils-all/linkdebug.s: Add .note.gnu.build-id
        section.

1 files changed, 132 insertions, 0 deletions

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 17c27ce..4326cd0 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -14194,6 +14194,138 @@ load_specific_debug_section (enum dwarf_section_display_enum  debug,
   return TRUE;
 }
 
+#if HAVE_LIBDEBUGINFOD
+/* Return a hex string representation of the build-id.  */
+unsigned char *
+get_build_id (void * data)
+{
+  Filedata * filedata = (Filedata *)data;
+  Elf_Internal_Shdr * shdr;
+  unsigned long i;
+
+  /* Iterate through notes to find note.gnu.build-id.  */
+  for (i = 0, shdr = filedata->section_headers;
+       i < filedata->file_header.e_shnum && shdr != NULL;
+       i++, shdr++)
+    {
+      if (shdr->sh_type != SHT_NOTE)
+        continue;
+
+      char * next;
+      char * end;
+      size_t data_remaining;
+      size_t min_notesz;
+      Elf_External_Note * enote;
+      Elf_Internal_Note inote;
+
+      bfd_vma offset = shdr->sh_offset;
+      bfd_vma align = shdr->sh_addralign;
+      bfd_vma length = shdr->sh_size;
+
+      enote = (Elf_External_Note *) get_section_contents (shdr, filedata);
+      if (enote == NULL)
+        continue;
+
+      if (align < 4)
+        align = 4;
+      else if (align != 4 && align != 8)
+        continue;
+
+      end = (char *) enote + length;
+      data_remaining = end - (char *) enote;
+
+      if (!is_ia64_vms (filedata))
+        {
+          min_notesz = offsetof (Elf_External_Note, name);
+          if (data_remaining < min_notesz)
+            {
+              warn (ngettext ("debuginfod: Corrupt note: only %ld byte remains, "
+                              "not enough for a full note\n",
+                              "Corrupt note: only %ld bytes remain, "
+                              "not enough for a full note\n",
+                              data_remaining),
+                    (long) data_remaining);
+              break;
+            }
+          data_remaining -= min_notesz;
+
+          inote.type     = BYTE_GET (enote->type);
+          inote.namesz   = BYTE_GET (enote->namesz);
+          inote.namedata = enote->name;
+          inote.descsz   = BYTE_GET (enote->descsz);
+          inote.descdata = ((char *) enote
+                            + ELF_NOTE_DESC_OFFSET (inote.namesz, align));
+          inote.descpos  = offset + (inote.descdata - (char *) enote);
+          next = ((char *) enote
+                  + ELF_NOTE_NEXT_OFFSET (inote.namesz, inote.descsz, align));
+        }
+      else
+        {
+          Elf64_External_VMS_Note *vms_enote;
+
+          /* PR binutils/15191
+             Make sure that there is enough data to read.  */
+          min_notesz = offsetof (Elf64_External_VMS_Note, name);
+          if (data_remaining < min_notesz)
+            {
+              warn (ngettext ("debuginfod: Corrupt note: only %ld byte remains, "
+                              "not enough for a full note\n",
+                              "Corrupt note: only %ld bytes remain, "
+                              "not enough for a full note\n",
+                              data_remaining),
+                    (long) data_remaining);
+              break;
+            }
+          data_remaining -= min_notesz;
+
+          vms_enote = (Elf64_External_VMS_Note *) enote;
+          inote.type     = BYTE_GET (vms_enote->type);
+          inote.namesz   = BYTE_GET (vms_enote->namesz);
+          inote.namedata = vms_enote->name;
+          inote.descsz   = BYTE_GET (vms_enote->descsz);
+          inote.descdata = inote.namedata + align_power (inote.namesz, 3);
+          inote.descpos  = offset + (inote.descdata - (char *) enote);
+          next = inote.descdata + align_power (inote.descsz, 3);
+        }
+
+      /* Skip malformed notes.  */
+      if ((size_t) (inote.descdata - inote.namedata) < inote.namesz
+          || (size_t) (inote.descdata - inote.namedata) > data_remaining
+          || (size_t) (next - inote.descdata) < inote.descsz
+          || ((size_t) (next - inote.descdata)
+              > data_remaining - (size_t) (inote.descdata - inote.namedata)))
+        {
+          warn (_("debuginfod: note with invalid namesz and/or descsz found\n"));
+          warn (_(" type: 0x%lx, namesize: 0x%08lx, descsize: 0x%08lx, alignment: %u\n"),
+                inote.type, inote.namesz, inote.descsz, (int) align);
+          continue;
+        }
+
+      /* Check if this is the build-id note. If so then convert the build-id
+         bytes to a hex string.  */
+      if (inote.namesz > 0
+          && const_strneq (inote.namedata, "GNU")
+          && inote.type == NT_GNU_BUILD_ID)
+        {
+          unsigned long j;
+          char * build_id;
+
+          build_id = malloc (inote.descsz * 2 + 1);
+          if (build_id == NULL)
+              return NULL;
+
+          for (j = 0; j < inote.descsz; ++j)
+            sprintf (build_id + (j * 2), "%02x", inote.descdata[j] & 0xff);
+          build_id[inote.descsz * 2] = '\0';
+
+          return (unsigned char *)build_id;
+        }
+    }
+
+  return NULL;
+}
+#endif /* HAVE_LIBDEBUGINFOD */
+
 /* If this is not NULL, load_debug_section will only look for sections
    within the list of sections given here.  */
 static unsigned int * section_subset = NULL;