lib/util: Move log_stack_trace() to common code

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13454
(cherry picked from commit bf9551902afdb32310db4a3381964c435dd08bf0)

3 files changed, 106 insertions, 0 deletions

diff --git a/lib/util/fault.c b/lib/util/fault.c
index fef82a3fcf7..e539aff9e7b 100644
--- a/lib/util/fault.c
+++ b/lib/util/fault.c
@@ -3,6 +3,7 @@
    Critical Fault handling
    Copyright (C) Andrew Tridgell 1992-1998
    Copyright (C) Tim Prouty 2009
+   Copyright (C) James Peach 2006
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -170,3 +171,106 @@ _PUBLIC_ void smb_panic(const char *why)
 	}
 	smb_panic_default(why);
 }
+
+
+
+/*******************************************************************
+ Print a backtrace of the stack to the debug log. This function
+ DELIBERATELY LEAKS MEMORY. The expectation is that you should
+ exit shortly after calling it.
+********************************************************************/
+
+/* Buffer size to use when printing backtraces */
+#define BACKTRACE_STACK_SIZE 64
+
+
+#ifdef HAVE_LIBUNWIND_H
+#include <libunwind.h>
+#endif
+
+#ifdef HAVE_EXECINFO_H
+#include <execinfo.h>
+#endif
+
+void log_stack_trace(void)
+{
+#ifdef HAVE_LIBUNWIND
+	/* Try to use libunwind before any other technique since on ia64
+	 * libunwind correctly walks the stack in more circumstances than
+	 * backtrace.
+	 */
+	unw_cursor_t cursor;
+	unw_context_t uc;
+	unsigned i = 0;
+
+	char procname[256];
+	unw_word_t ip, sp, off;
+
+	procname[sizeof(procname) - 1] = '\0';
+
+	if (unw_getcontext(&uc) != 0) {
+		goto libunwind_failed;
+	}
+
+	if (unw_init_local(&cursor, &uc) != 0) {
+		goto libunwind_failed;
+	}
+
+	DEBUG(0, ("BACKTRACE:\n"));
+
+	do {
+	    ip = sp = 0;
+	    unw_get_reg(&cursor, UNW_REG_IP, &ip);
+	    unw_get_reg(&cursor, UNW_REG_SP, &sp);
+
+	    switch (unw_get_proc_name(&cursor,
+			procname, sizeof(procname) - 1, &off) ) {
+	    case 0:
+		    /* Name found. */
+	    case -UNW_ENOMEM:
+		    /* Name truncated. */
+		    DEBUGADD(0, (" #%u %s + %#llx [ip=%#llx] [sp=%#llx]\n",
+			    i, procname, (long long)off,
+			    (long long)ip, (long long) sp));
+		    break;
+	    default:
+	    /* case -UNW_ENOINFO: */
+	    /* case -UNW_EUNSPEC: */
+		    /* No symbol name found. */
+		    DEBUGADD(0, (" #%u %s [ip=%#llx] [sp=%#llx]\n",
+			    i, "<unknown symbol>",
+			    (long long)ip, (long long) sp));
+	    }
+	    ++i;
+	} while (unw_step(&cursor) > 0);
+
+	return;
+
+libunwind_failed:
+	DEBUG(0, ("unable to produce a stack trace with libunwind\n"));
+
+#elif HAVE_BACKTRACE_SYMBOLS
+	void *backtrace_stack[BACKTRACE_STACK_SIZE];
+	size_t backtrace_size;
+	char **backtrace_strings;
+
+	/* get the backtrace (stack frames) */
+	backtrace_size = backtrace(backtrace_stack,BACKTRACE_STACK_SIZE);
+	backtrace_strings = backtrace_symbols(backtrace_stack, backtrace_size);
+
+	DEBUG(0, ("BACKTRACE: %lu stack frames:\n",
+		  (unsigned long)backtrace_size));
+
+	if (backtrace_strings) {
+		int i;
+
+		for (i = 0; i < backtrace_size; i++)
+			DEBUGADD(0, (" #%u %s\n", i, backtrace_strings[i]));
+
+		/* Leak the backtrace_strings, rather than risk what free() might do */
+	}
+
+#else
+	DEBUG(0, ("unable to produce a stack trace on this platform\n"));
+#endif
+}
diff --git a/lib/util/fault.h b/lib/util/fault.h
index 0ac6cb9ceb5..dfa339b7650 100644
--- a/lib/util/fault.h
+++ b/lib/util/fault.h
@@ -53,5 +53,6 @@ void fault_setup(void);
 void fault_setup_disable(void);
 _NORETURN_ void smb_panic(const char *reason);
 
+void log_stack_trace(void);
 
 #endif /* _SAMBA_FAULT_H_ */
diff --git a/lib/util/wscript_configure b/lib/util/wscript_configure
index 8e5a59c8480..2a8dbef699b 100644
--- a/lib/util/wscript_configure
+++ b/lib/util/wscript_configure
@@ -6,6 +6,7 @@ if Options.options.disable_fault_handling:
 
 # backtrace could be in libexecinfo or in libc
 conf.CHECK_FUNCS_IN('backtrace backtrace_symbols', 'execinfo', checklibc=True, headers='execinfo.h')
+conf.CHECK_HEADERS('execinfo.h libunwind.h')
 
 conf.CHECK_STRUCTURE_MEMBER('struct statvfs', 'f_frsize', define='HAVE_FRSIZE', headers='sys/statvfs.h')