[PATCH] Provide a simple backtrace in the samba AD DC also
Andrew Bartlett
abartlet at samba.org
Tue Apr 10 05:00:32 UTC 2018
smbd has for a long time been able to produce a simple internal
backtrace.
This patch allows 'samba' to do the same, by bringing that code into
lib/util. An un-used IRIX mode, lost since the move to waf, was
removed to allow this to happen. (That mode used become_root()).
This is important because gdb_backtrace as a panic action is not
compatible with gitlab CI, so without this we have no way to tell where
the fault is.
The cstyle.py failures are all in the moved code:
ad84ecfd836 s3-lib: Remove support for libexc for IRIX backtraces
2469ab654a3 lib/util: Log PANIC before calling pacic action just like
s3
212ae4db4bb lib/util: Move log_stack_trace() to common code
:lib/util/fault.c:
178 Comment line does not have * aligned with top
179 Comment line does not have * aligned with top
180 Comment line does not have * aligned with top
181 Garbage before * in comment line
181 Comment is 3+ lines but is not formatted as block comment
197 Preprocessor statement in function body
201 Comment is 3+ lines but is not formatted as block comment
227 Space before close parenthesis
234 Space after cast operator (or inline if/while body)
242 Space after cast operator (or inline if/while body)
252 Preprocessor statement in function body
273 Preprocessor statement in function body
275 Preprocessor statement in function body
19dba766ad6 lib/util: Call log_stack_trace() in smb_panic_default()
Please review and push,
Andrew Bartlett
--
Andrew Bartlett
https://samba.org/~abartlet/
Authentication Developer, Samba Team https://samba.org
Samba Development and Support, Catalyst IT
https://catalyst.net.nz/services/samba
-------------- next part --------------
From ad84ecfd836f07bbfe050fe203d352490c85decc Mon Sep 17 00:00:00 2001
From: Andrew Bartlett <abartlet at samba.org>
Date: Tue, 10 Apr 2018 15:54:10 +1200
Subject: [PATCH 1/4] s3-lib: Remove support for libexc for IRIX backtraces
IRIX is long dead, and this code needs become_root() which is not in
the top level code.
Additionally, the check for libexc never made it into waf, so this
has been dead code since Samba 4.1.
Signed-off-by: Andrew Bartlett <abartlet at samba.org>
---
source3/lib/util.c | 42 ------------------------------------------
source3/wscript | 2 +-
2 files changed, 1 insertion(+), 43 deletions(-)
diff --git a/source3/lib/util.c b/source3/lib/util.c
index ae9fe71c974..98c47b3df9f 100644
--- a/source3/lib/util.c
+++ b/source3/lib/util.c
@@ -852,10 +852,6 @@ void smb_panic_s3(const char *why)
#include <execinfo.h>
#endif
-#ifdef HAVE_LIBEXC_H
-#include <libexc.h>
-#endif
-
void log_stack_trace(void)
{
#ifdef HAVE_LIBUNWIND
@@ -934,44 +930,6 @@ libunwind_failed:
/* Leak the backtrace_strings, rather than risk what free() might do */
}
-#elif HAVE_LIBEXC
-
- /* The IRIX libexc library provides an API for unwinding the stack. See
- * libexc(3) for details. Apparantly trace_back_stack leaks memory, but
- * since we are about to abort anyway, it hardly matters.
- */
-
-#define NAMESIZE 32 /* Arbitrary */
-
- __uint64_t addrs[BACKTRACE_STACK_SIZE];
- char * names[BACKTRACE_STACK_SIZE];
- char namebuf[BACKTRACE_STACK_SIZE * NAMESIZE];
-
- int i;
- int levels;
-
- ZERO_ARRAY(addrs);
- ZERO_ARRAY(names);
- ZERO_ARRAY(namebuf);
-
- /* We need to be root so we can open our /proc entry to walk
- * our stack. It also helps when we want to dump core.
- */
- become_root();
-
- for (i = 0; i < BACKTRACE_STACK_SIZE; i++) {
- names[i] = namebuf + (i * NAMESIZE);
- }
-
- levels = trace_back_stack(0, addrs, names,
- BACKTRACE_STACK_SIZE, NAMESIZE - 1);
-
- DEBUG(0, ("BACKTRACE: %d stack frames:\n", levels));
- for (i = 0; i < levels; i++) {
- DEBUGADD(0, (" #%d 0x%llx %s\n", i, addrs[i], names[i]));
- }
-#undef NAMESIZE
-
#else
DEBUG(0, ("unable to produce a stack trace on this platform\n"));
#endif
diff --git a/source3/wscript b/source3/wscript
index 826877d3dfd..8d658b2f53e 100644
--- a/source3/wscript
+++ b/source3/wscript
@@ -96,7 +96,7 @@ def configure(conf):
# We crash without vfs_default
required_static_modules.extend(TO_LIST('vfs_default'))
- conf.CHECK_HEADERS('execinfo.h libexc.h libunwind.h netdb.h')
+ conf.CHECK_HEADERS('execinfo.h libunwind.h netdb.h')
conf.CHECK_HEADERS('linux/falloc.h linux/ioctl.h')
conf.CHECK_FUNCS('getcwd fchown chmod fchmod mknod')
--
2.11.0
From 2469ab654a3c39099ec6423acb5927182849a3b1 Mon Sep 17 00:00:00 2001
From: Andrew Bartlett <abartlet at samba.org>
Date: Tue, 10 Apr 2018 16:06:12 +1200
Subject: [PATCH 2/4] lib/util: Log PANIC before calling pacic action just like
s3
This is like the changes made in s3 by
4fa555980070d78b39711ef21d77628d26055bc2
Signed-off-by: Andrew Bartlett <abartlet at samba.org>
---
lib/util/fault.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/util/fault.c b/lib/util/fault.c
index 54d84711742..887c7d6c238 100644
--- a/lib/util/fault.c
+++ b/lib/util/fault.c
@@ -123,6 +123,9 @@ _PUBLIC_ const char *panic_action = NULL;
static void smb_panic_default(const char *why) _NORETURN_;
static void smb_panic_default(const char *why)
{
+ DEBUG(0,("PANIC (pid %llu): %s\n",
+ (unsigned long long)getpid(), why));
+
#if defined(HAVE_PRCTL) && defined(PR_SET_PTRACER)
/*
* Make sure all children can attach a debugger.
@@ -148,7 +151,6 @@ static void smb_panic_default(const char *why)
WEXITSTATUS(result)));
}
}
- DEBUG(0,("PANIC: %s\n", why));
#ifdef SIGABRT
CatchSignal(SIGABRT, SIG_DFL);
--
2.11.0
From 212ae4db4bb433de5e3a70fcb797c6dc21f4d795 Mon Sep 17 00:00:00 2001
From: Andrew Bartlett <abartlet at samba.org>
Date: Tue, 10 Apr 2018 16:35:07 +1200
Subject: [PATCH 3/4] lib/util: Move log_stack_trace() to common code
Signed-off-by: Andrew Bartlett <abartlet at samba.org>
---
lib/util/fault.c | 104 +++++++++++++++++++++++++++++++++++++++++++++
lib/util/fault.h | 1 +
lib/util/wscript_configure | 1 +
source3/include/local.h | 3 --
source3/include/proto.h | 1 -
source3/lib/util.c | 97 ------------------------------------------
source3/wscript | 2 +-
7 files changed, 107 insertions(+), 102 deletions(-)
diff --git a/lib/util/fault.c b/lib/util/fault.c
index 887c7d6c238..af06c9484db 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')
diff --git a/source3/include/local.h b/source3/include/local.h
index 7f97d4ece9c..c2be1ff3b7f 100644
--- a/source3/include/local.h
+++ b/source3/include/local.h
@@ -172,9 +172,6 @@
/* Number in seconds for winbindd to wait for the mutex. Make this 2 * smbd wait time. */
#define WINBIND_SERVER_MUTEX_WAIT_TIME (( ((NUM_CLI_AUTH_CONNECT_RETRIES) * ((CLI_AUTH_TIMEOUT)/1000)) + 5)*2)
-/* Buffer size to use when printing backtraces */
-#define BACKTRACE_STACK_SIZE 64
-
/* size of listen() backlog in smbd */
#define SMBD_LISTEN_BACKLOG 50
diff --git a/source3/include/proto.h b/source3/include/proto.h
index fa87407ff24..2bc5ab2f532 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -356,7 +356,6 @@ char *gidtoname(gid_t gid);
uid_t nametouid(const char *name);
gid_t nametogid(const char *name);
void smb_panic_s3(const char *why);
-void log_stack_trace(void);
const char *readdirname(DIR *p);
bool is_in_path(const char *name, name_compare_entry *namelist, bool case_sensitive);
void set_namearray(name_compare_entry **ppname_array, const char *namelist);
diff --git a/source3/lib/util.c b/source3/lib/util.c
index 98c47b3df9f..5f786f95d3e 100644
--- a/source3/lib/util.c
+++ b/source3/lib/util.c
@@ -839,103 +839,6 @@ void smb_panic_s3(const char *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.
-********************************************************************/
-
-#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
-}
-
-/*******************************************************************
A readdir wrapper which just returns the file name.
********************************************************************/
diff --git a/source3/wscript b/source3/wscript
index 8d658b2f53e..ab64e80214e 100644
--- a/source3/wscript
+++ b/source3/wscript
@@ -96,7 +96,7 @@ def configure(conf):
# We crash without vfs_default
required_static_modules.extend(TO_LIST('vfs_default'))
- conf.CHECK_HEADERS('execinfo.h libunwind.h netdb.h')
+ conf.CHECK_HEADERS('netdb.h')
conf.CHECK_HEADERS('linux/falloc.h linux/ioctl.h')
conf.CHECK_FUNCS('getcwd fchown chmod fchmod mknod')
--
2.11.0
From 19dba766ad65916fe329db77f6bdd8dc59d882a2 Mon Sep 17 00:00:00 2001
From: Andrew Bartlett <abartlet at samba.org>
Date: Tue, 10 Apr 2018 16:37:45 +1200
Subject: [PATCH 4/4] lib/util: Call log_stack_trace() in smb_panic_default()
This matches the AD DC with the behaviour in smbd.
Signed-off-by: Andrew Bartlett <abartlet at samba.org>
---
lib/util/fault.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/util/fault.c b/lib/util/fault.c
index af06c9484db..77415e1134d 100644
--- a/lib/util/fault.c
+++ b/lib/util/fault.c
@@ -126,6 +126,7 @@ static void smb_panic_default(const char *why)
{
DEBUG(0,("PANIC (pid %llu): %s\n",
(unsigned long long)getpid(), why));
+ log_stack_trace();
#if defined(HAVE_PRCTL) && defined(PR_SET_PTRACER)
/*
--
2.11.0
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