libdwelf: Add dwelf_elf_gnu_build_id.

Move internal function __libdwfl_find_build_id to libdwelf and use it to
add a public dwelf_elf_gnu_build_id function to extract the NT_GNU_BUILD_ID
from an ELF file using either the shdrs or phdrs. Adjust internal callers
and add a testcase.

Signed-off-by: Mark Wielaard <[email protected]>

5 files changed, 135 insertions, 4 deletions

diff --git a/tests/ChangeLog b/tests/ChangeLog
index 1c30778d..ff396d50 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,11 @@
+2014-04-30  Mark Wielaard  <[email protected]>
+
+	* buildid.c, buildid.sh, testfile42_noshdrs.bz2: New files.
+	* Makefile.am (check_PROGRAMS): Add buildid.
+	(TESTS): Add run-buildid.sh.
+	(EXTRA_DISTS): Add run-buildid.sh and testfile42_noshdrs.bz2.
+	(buildid_LDADD): New variable.
+
 2014-04-24  Florian Weimer  <[email protected]>
 
 	* allfcts.c (setup_alt): New function.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 33803fca..dd110a52 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -49,7 +49,9 @@ check_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
 		  alldts md5-sha1-test typeiter typeiter2 low_high_pc \
 		  test-elf_cntl_gelf_getshdr dwflsyms dwfllines \
 		  dwfl-report-elf-align varlocs backtrace backtrace-child \
-		  backtrace-data backtrace-dwarf debuglink debugaltlink
+		  backtrace-data backtrace-dwarf debuglink debugaltlink \
+		  buildid
+
 asm_TESTS = asm-tst1 asm-tst2 asm-tst3 asm-tst4 asm-tst5 \
 	    asm-tst6 asm-tst7 asm-tst8 asm-tst9
 
@@ -86,7 +88,7 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
 	run-readelf-macro.sh run-readelf-loc.sh \
 	run-readelf-aranges.sh run-readelf-line.sh \
 	run-native-test.sh run-bug1-test.sh \
-	run-debuglink.sh run-debugaltlink.sh \
+	run-debuglink.sh run-debugaltlink.sh run-buildid.sh \
 	dwfl-bug-addr-overflow run-addrname-test.sh \
 	dwfl-bug-fd-leak dwfl-bug-report \
 	run-dwfl-bug-offline-rel.sh run-dwfl-addr-sect.sh \
@@ -176,14 +178,15 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh \
 	     run-readelf-test1.sh run-readelf-test2.sh run-readelf-test3.sh \
 	     run-readelf-test4.sh run-readelf-twofiles.sh \
 	     run-bug1-test.sh testfile28.bz2 testfile28.rdwr.bz2 \
-	     run-debuglink.sh run-debugaltlink.sh \
+	     run-debuglink.sh run-debugaltlink.sh run-buildid.sh \
 	     testfile29.bz2 testfile29.rdwr.bz2 \
 	     testfile30.bz2 testfile31.bz2 testfile32.bz2 testfile33.bz2 \
 	     testfile34.bz2 testfile35.bz2 testfile35.debug.bz2 \
 	     testfile36.bz2 testfile36.debug.bz2 \
 	     testfile37.bz2 testfile37.debug.bz2 \
 	     testfile38.bz2 testfile39.bz2 testfile40.bz2 testfile40.debug.bz2 \
-	     testfile41.bz2 testfile42.bz2 testfile43.bz2 \
+	     testfile41.bz2 testfile42.bz2 testfile42_noshdrs.bz2 \
+	     testfile43.bz2 \
 	     testfile44.S.bz2 testfile44.expect.bz2 run-disasm-x86.sh \
 	     testfile45.S.bz2 testfile45.expect.bz2 run-disasm-x86-64.sh \
 	     testfile46.bz2 testfile47.bz2 testfile48.bz2 testfile48.debug.bz2 \
@@ -406,6 +409,7 @@ backtrace_dwarf_CFLAGS = -Wno-unused-parameter
 backtrace_dwarf_LDADD = $(libdw) $(libelf)
 debuglink_LDADD = $(libdw) $(libelf)
 debugaltlink_LDADD = $(libdw) $(libelf)
+buildid_LDADD = $(libdw) $(libelf)
 
 if GCOV
 check: check-am coverage
diff --git a/tests/buildid.c b/tests/buildid.c
new file mode 100644
index 00000000..87c18773
--- /dev/null
+++ b/tests/buildid.c
@@ -0,0 +1,81 @@
+/* Test program for dwelf_elf_gnu_build_id, print build ID.
+   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 the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+#include <assert.h>
+#include <inttypes.h>
+#include <err.h>
+#include <errno.h>
+#include ELFUTILS_HEADER(elf)
+#include ELFUTILS_HEADER(dwelf)
+#include <stdio.h>
+#include <error.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int
+main (int argc, char *argv[])
+{
+  if (argc < 2)
+    error (EXIT_FAILURE, 0, "No input file given");
+
+  elf_version (EV_CURRENT);
+
+  for (int i = 1; i < argc; i++)
+    {
+      const char *file = argv[i];
+      int fd = open (file, O_RDONLY);
+      if (fd < 0)
+	error (EXIT_FAILURE, errno, "couldn't open file '%s'", file);
+
+      Elf *elf = elf_begin (fd, ELF_C_READ, NULL);
+      if (elf == NULL)
+	{
+	  printf("%s: elf_begin failed: %s\n", file, elf_errmsg (-1));
+	  close (fd);
+	  continue;
+	}
+
+      const void *build_id;
+      ssize_t len = dwelf_elf_gnu_build_id (elf, &build_id);
+      switch (len)
+	{
+	case 0:
+	  printf ("%s: <no NT_GNU_BUILD_ID note>\n", file);
+	  break;
+	case -1:
+	  errx (1, "dwelf_elf_gnu_build_id (%s): %s",
+		file, elf_errmsg (-1));
+	default:
+	  printf ("%s: build ID: ", file);
+	  const unsigned char *p = build_id;
+	  const unsigned char *end = p + len;
+	  while (p < end)
+	      printf("%02x", (unsigned)*p++);
+	  putchar('\n');
+	}
+
+      elf_end (elf);
+      close (fd);
+    }
+
+  return 0;
+}
diff --git a/tests/run-buildid.sh b/tests/run-buildid.sh
new file mode 100755
index 00000000..31cec24d
--- /dev/null
+++ b/tests/run-buildid.sh
@@ -0,0 +1,38 @@
+#! /bin/sh
+# 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 the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/test-subr.sh
+
+# Just some random testfiles, four with, one without build-id,
+# and one without shdrs forcing reading the notes through phdrs.
+# eu-strip --strip-sections -g --output=testfile42_noshdrs testfile42
+# See also run-debugaltlink.sh.
+testfiles testfile42 testfile_multi.dwz testfile-dwzstr.multi \
+    test-offset-loop.alt testfile14 testfile42_noshdrs
+
+testrun_compare  ${abs_builddir}/buildid testfile42 testfile42_noshdrs \
+    testfile_multi.dwz testfile-dwzstr.multi \
+    test-offset-loop.alt testfile14 <<\EOF
+testfile42: build ID: d826d96c4d097bdc5c254b1f7344a907e36b0439
+testfile42_noshdrs: build ID: d826d96c4d097bdc5c254b1f7344a907e36b0439
+testfile_multi.dwz: build ID: a0d6c06e0d912d74033b6fe2808753cae8f6f594
+testfile-dwzstr.multi: build ID: 6da22627dae55c1d62cf9122827c665e240a056b
+test-offset-loop.alt: build ID: 066bbf1a7bc5676f5015ee1966a088f23bdb83ae
+testfile14: <no NT_GNU_BUILD_ID note>
+EOF
+
+exit 0
diff --git a/tests/testfile42_noshdrs.bz2 b/tests/testfile42_noshdrs.bz2
new file mode 100644
index 00000000..e50f7500
--- /dev/null
+++ b/tests/testfile42_noshdrs.bz2