Squashed 'third_party/elfutils/' content from commit 555e15e

Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/tests/backtrace-dwarf.c b/tests/backtrace-dwarf.c
new file mode 100644
index 0000000..2dc8a9a
--- /dev/null
+++ b/tests/backtrace-dwarf.c
@@ -0,0 +1,170 @@
+/* Test program for unwinding of complicated DWARF expressions.
+   Copyright (C) 2013, 2015 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 <signal.h>
+#include <inttypes.h>
+#include <stdio_ext.h>
+#include <locale.h>
+#include <errno.h>
+#include <error.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include ELFUTILS_HEADER(dwfl)
+
+#ifndef __linux__
+
+int
+main (int argc __attribute__ ((unused)), char **argv)
+{
+  fprintf (stderr, "%s: Unwinding not supported for this architecture\n",
+           argv[0]);
+  return 77;
+}
+
+#else /* __linux__ */
+#include <sys/ptrace.h>
+
+#define main cleanup_13_main
+#include "cleanup-13.c"
+#undef main
+
+static void
+report_pid (Dwfl *dwfl, pid_t pid)
+{
+  int result = dwfl_linux_proc_report (dwfl, pid);
+  if (result < 0)
+    error (2, 0, "dwfl_linux_proc_report: %s", dwfl_errmsg (-1));
+  else if (result > 0)
+    error (2, result, "dwfl_linux_proc_report");
+
+  if (dwfl_report_end (dwfl, NULL, NULL) != 0)
+    error (2, 0, "dwfl_report_end: %s", dwfl_errmsg (-1));
+
+  result = dwfl_linux_proc_attach (dwfl, pid, true);
+  if (result < 0)
+    error (2, 0, "dwfl_linux_proc_attach: %s", dwfl_errmsg (-1));
+  else if (result > 0)
+    error (2, result, "dwfl_linux_proc_attach");
+}
+
+static Dwfl *
+pid_to_dwfl (pid_t pid)
+{
+  static char *debuginfo_path;
+  static const Dwfl_Callbacks proc_callbacks =
+    {
+      .find_debuginfo = dwfl_standard_find_debuginfo,
+      .debuginfo_path = &debuginfo_path,
+
+      .find_elf = dwfl_linux_proc_find_elf,
+    };
+  Dwfl *dwfl = dwfl_begin (&proc_callbacks);
+  if (dwfl == NULL)
+    error (2, 0, "dwfl_begin: %s", dwfl_errmsg (-1));
+  report_pid (dwfl, pid);
+  return dwfl;
+}
+
+static int
+frame_callback (Dwfl_Frame *state, void *frame_arg)
+{
+  Dwarf_Addr pc;
+  bool isactivation;
+  if (! dwfl_frame_pc (state, &pc, &isactivation))
+    {
+      error (0, 0, "%s", dwfl_errmsg (-1));
+      return DWARF_CB_ABORT;
+    }
+  Dwarf_Addr pc_adjusted = pc - (isactivation ? 0 : 1);
+
+  /* Get PC->SYMNAME.  */
+  Dwfl_Thread *thread = dwfl_frame_thread (state);
+  Dwfl *dwfl = dwfl_thread_dwfl (thread);
+  Dwfl_Module *mod = dwfl_addrmodule (dwfl, pc_adjusted);
+  const char *symname = NULL;
+  if (mod)
+    symname = dwfl_module_addrname (mod, pc_adjusted);
+
+  printf ("%#" PRIx64 "\t%s\n", (uint64_t) pc, symname);
+
+  if (symname && (strcmp (symname, "main") == 0
+		  || strcmp (symname, ".main") == 0))
+    {
+      kill (dwfl_pid (dwfl), SIGKILL);
+      exit (0);
+    }
+
+  return DWARF_CB_OK;
+}
+
+static int
+thread_callback (Dwfl_Thread *thread, void *thread_arg)
+{
+  dwfl_thread_getframes (thread, frame_callback, NULL);
+  /* frame_callback shall exit (0) on success.  */
+  error (1, 0, "dwfl_thread_getframes: %s", dwfl_errmsg (-1));
+  return DWARF_CB_ABORT;
+}
+
+int
+main (int argc __attribute__ ((unused)), char **argv)
+{
+  /* We use no threads here which can interfere with handling a stream.  */
+  __fsetlocking (stdin, FSETLOCKING_BYCALLER);
+  __fsetlocking (stdout, FSETLOCKING_BYCALLER);
+  __fsetlocking (stderr, FSETLOCKING_BYCALLER);
+
+  /* Set locale.  */
+  (void) setlocale (LC_ALL, "");
+
+  elf_version (EV_CURRENT);
+
+  pid_t pid = fork ();
+  switch (pid)
+  {
+    case -1:
+      abort ();
+    case 0:;
+      long l = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
+      assert (errno == 0);
+      assert (l == 0);
+      cleanup_13_main ();
+      abort ();
+    default:
+      break;
+  }
+
+  errno = 0;
+  int status;
+  pid_t got = waitpid (pid, &status, 0);
+  assert (errno == 0);
+  assert (got == pid);
+  assert (WIFSTOPPED (status));
+  assert (WSTOPSIG (status) == SIGABRT);
+
+  Dwfl *dwfl = pid_to_dwfl (pid);
+  dwfl_getthreads (dwfl, thread_callback, NULL);
+
+  /* There is an exit (0) call if we find the "main" frame,  */
+  error (1, 0, "dwfl_getthreads: %s", dwfl_errmsg (-1));
+}
+
+#endif /* ! __linux__ */
+