Commit a8d48575 authored by Thibault Saunier's avatar Thibault Saunier

gst: Use libunwind/libdw to generate backtraces if avalaible

Making the gst_debug_print_trace function more generally useful.

API:
  + gst_debug_get_trace

https://bugzilla.gnome.org/show_bug.cgi?id=772555
parent 050f486d
......@@ -438,3 +438,6 @@
#mesondefine HAVE_DECL_STRSIGNAL
#mesondefine HAVE_GETRUSAGE
#mesondefine HAVE_SYS_RESOURCE_H
#mesondefine HAVE_UNWIND
#mesondefine HAVE_DW
#mesondefine HAVE_BACKTRACE
......@@ -828,6 +828,15 @@ AM_CONDITIONAL(HAVE_GTK, test "x$HAVE_GTK" = "xyes")
dnl libunwind is optionally used by the leaks tracer
PKG_CHECK_MODULES(UNWIND, libunwind, HAVE_UNWIND=yes, HAVE_UNWIND=no)
if test "x$HAVE_UNWIND" = "xyes"; then
AC_DEFINE(HAVE_UNWIND, 1, [libunwind available])
fi
dnl libdw is optionally used to add source lines and numbers to backtraces
PKG_CHECK_MODULES(DW, libdw, HAVE_DW=yes, HAVE_DW=no)
if test "x$HAVE_DW" = "xyes"; then
AC_DEFINE(HAVE_DW, 1, [libdw available])
fi
dnl Check for backtrace() from libc
AC_CHECK_FUNC(backtrace, [
......@@ -836,10 +845,6 @@ AC_CHECK_FUNC(backtrace, [
], [], [])
])
if test "x$HAVE_UNWIND" = "xyes"; then
AC_DEFINE(HAVE_UNWIND, 1, [libunwind available])
fi
dnl building of unit test libraries
AC_ARG_ENABLE(check,
AS_HELP_STRING([--disable-check],[disable building unit test libraries]),
......@@ -1161,6 +1166,7 @@ Configuration
Unit testing support : ${BUILD_CHECK}
PTP clock support : ${HAVE_PTP}
libunwind support : ${HAVE_UNWIND}
libdw support : ${HAVE_DW}
Debug : ${USE_DEBUG}
Profiling : ${USE_PROFILING}
......
......@@ -1379,6 +1379,7 @@ GST_DEBUG_FUNCPTR_NAME
GST_DEBUG_BIN_TO_DOT_FILE
GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS
gst_debug_print_stack_trace
gst_debug_get_stack_trace
GST_TIME_FORMAT
GST_TIME_ARGS
GST_STIME_FORMAT
......
......@@ -141,6 +141,8 @@ libgstreamer_@GST_API_VERSION@_la_CFLAGS = \
-DGST_API_VERSION=\""$(GST_API_VERSION)"\" \
-DGST_DISABLE_DEPRECATED \
$(VALGRIND_CFLAGS) \
$(UNWIND_CFLAGS) \
$(DW_CFLAGS) \
$(GST_ALL_CFLAGS)
libgstreamer_@GST_API_VERSION@_la_LIBADD = \
......@@ -149,6 +151,8 @@ libgstreamer_@GST_API_VERSION@_la_LIBADD = \
$(GST_ALL_LIBS) \
$(WIN32_LIBS) \
$(SOCKET_LIBS) \
$(UNWIND_LIBS) \
$(DW_LIBS) \
$(LIBM)
libgstreamer_@GST_API_VERSION@_la_LDFLAGS = \
......
......@@ -90,7 +90,6 @@
#undef gst_debug_add_log_function
#ifndef GST_DISABLE_GST_DEBUG
#ifdef HAVE_DLFCN_H
# include <dlfcn.h>
#endif
......@@ -127,9 +126,34 @@
static char *gst_info_printf_pointer_extension_func (const char *format,
void *ptr);
#else /* GST_DISABLE_GST_DEBUG */
#include <glib/gprintf.h>
#endif /* !GST_DISABLE_GST_DEBUG */
#ifdef HAVE_UNWIND
/* No need for remote debugging so turn on the 'local only' optimizations in
* libunwind */
#define UNW_LOCAL_ONLY
#include <libunwind.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#ifdef HAVE_DW
#include <elfutils/libdwfl.h>
#endif /* HAVE_DW */
#endif /* HAVE_UNWIND */
#ifdef HAVE_BACKTRACE
#include <execinfo.h>
#define BT_BUF_SIZE 100
#endif /* HAVE_BACKTRACE */
extern gboolean gst_is_initialized (void);
/* we want these symbols exported even if debug is disabled, to maintain
......@@ -2253,7 +2277,6 @@ _gst_debug_dump_mem (GstDebugCategory * cat, const gchar * file,
* fallback function that cleans up the format string and replaces all pointer
* extension formats with plain %p. */
#ifdef GST_DISABLE_GST_DEBUG
#include <glib/gprintf.h>
int
__gst_info_fallback_vasprintf (char **result, char const *format, va_list args)
{
......@@ -2412,15 +2435,16 @@ __cyg_profile_func_exit (void *this_fn, void *call_site)
}
/**
* gst_debug_print_stack_trace:
* gst_debug_get_stack_trace:
*
* If GST_ENABLE_FUNC_INSTRUMENTATION is defined a stacktrace is available for
* gstreamer code, which can be printed with this function.
* If GST_ENABLE_FUNC_INSTRUMENTATION is defined or libunwind or
* glibc backtrace are present, a stack trace is return.
*/
void
gst_debug_print_stack_trace (void)
gchar *
gst_debug_get_stack_trace (void)
{
GSList *walk = stack_trace;
GString *trace = g_string_new (NULL);
gint count = 0;
if (walk)
......@@ -2429,16 +2453,162 @@ gst_debug_print_stack_trace (void)
while (walk) {
gchar *name = (gchar *) walk->data;
g_print ("#%-2d %s\n", count++, name);
g_string_append (trace, "#%-2d %s\n", count++, name);
walk = g_slist_next (walk);
}
return g_string_free (trace, FALSE);
}
#else
void
gst_debug_print_stack_trace (void)
#ifdef HAVE_UNWIND
#ifdef HAVE_DW
static gboolean
append_debug_info (GString * trace, const void *ip)
{
Dwfl *dwfl;
Dwfl_Line *line;
Dwarf_Addr addr;
Dwfl_Module *module;
const gchar *function_name;
gchar *debuginfo_path = NULL;
Dwfl_Callbacks callbacks = {
.find_elf = dwfl_linux_proc_find_elf,
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
};
dwfl = dwfl_begin (&callbacks);
if (!dwfl)
return FALSE;
if (dwfl_linux_proc_report (dwfl, getpid ()) != 0)
return FALSE;
if (dwfl_report_end (dwfl, NULL, NULL))
return FALSE;
addr = (uintptr_t) ip;
module = dwfl_addrmodule (dwfl, addr);
function_name = dwfl_module_addrname (module, addr);
g_string_append_printf (trace, "%s(", function_name ? function_name : "??");
line = dwfl_getsrc (dwfl, addr);
if (line != NULL) {
gint nline;
Dwarf_Addr addr;
const gchar *filename = dwfl_lineinfo (line, &addr,
&nline, NULL, NULL, NULL);
g_string_append_printf (trace, "%s:%d", strrchr (filename,
G_DIR_SEPARATOR) + 1, nline);
} else {
const gchar *eflfile = NULL;
dwfl_module_info (module, NULL, NULL, NULL, NULL, NULL, &eflfile, NULL);
g_string_append_printf (trace, "%s:%p", eflfile ? eflfile : "??", ip);
}
return TRUE;
}
#endif /* HAVE_DW */
static gchar *
generate_unwind_trace (void)
{
/* nothing because it's compiled out */
unw_context_t uc;
unw_cursor_t cursor;
gboolean use_libunwind = TRUE;
GString *trace = g_string_new (NULL);
unw_getcontext (&uc);
unw_init_local (&cursor, &uc);
while (unw_step (&cursor) > 0) {
#ifdef HAVE_DW
unw_word_t ip;
unw_get_reg (&cursor, UNW_REG_IP, &ip);
if (append_debug_info (trace, (void *) (ip - 4))) {
use_libunwind = FALSE;
g_string_append (trace, ")\n");
}
#endif /* HAVE_DW */
if (use_libunwind) {
char name[32];
unw_word_t offset = 0;
unw_get_proc_name (&cursor, name, sizeof (name), &offset);
g_string_append_printf (trace, "%s (0x%" G_GSIZE_FORMAT ")\n", name,
(gsize) offset);
}
}
return g_string_free (trace, FALSE);
}
#endif /* HAVE_UNWIND */
#ifdef HAVE_BACKTRACE
static gchar *
generate_backtrace_trace (void)
{
int j, nptrs;
void *buffer[BT_BUF_SIZE];
char **strings;
GString *trace;
trace = g_string_new (NULL);
nptrs = backtrace (buffer, BT_BUF_SIZE);
strings = backtrace_symbols (buffer, nptrs);
if (!strings)
return NULL;
for (j = 0; j < nptrs; j++)
g_string_append_printf (trace, "%s\n", strings[j]);
return g_string_free (trace, FALSE);
}
#endif /* HAVE_BACKTRACE */
gchar *
gst_debug_get_stack_trace (void)
{
gchar *trace = NULL;
#ifdef HAVE_UNWIND
trace = generate_unwind_trace ();
if (trace)
return trace;
#endif /* HAVE_UNWIND */
#ifdef HAVE_BACKTRACE
trace = generate_backtrace_trace ();
#endif /* HAVE_BACKTRACE */
return trace;
}
#endif /* GST_ENABLE_FUNC_INSTRUMENTATION */
/**
* gst_debug_print_stack_trace:
*
* If GST_ENABLE_FUNC_INSTRUMENTATION is defined or libunwind or
* glibc backtrace are present, a stack trace is printed.
*/
void
gst_debug_print_stack_trace (void)
{
gchar *trace = gst_debug_get_stack_trace ();
if (trace)
g_print ("%s\n", trace);
g_free (trace);
}
......@@ -1564,6 +1564,7 @@ GST_TRACE (const char *format, ...)
void gst_debug_print_stack_trace (void);
gchar * gst_debug_get_stack_trace (void);
G_END_DECLS
......
......@@ -202,7 +202,7 @@ if libtype != 'shared'
include_directories('parse')],
install : true,
link_with : printf_lib,
dependencies : [gobject_dep, gmodule_dep, glib_dep, mathlib] + platform_deps,
dependencies : [gobject_dep, gmodule_dep, glib_dep, mathlib, unwind_dep, dw_dep] + platform_deps,
)
libgst = libgst_static
endif
......@@ -221,7 +221,7 @@ if libtype != 'static'
include_directories('parse')],
link_with : printf_lib,
install : true,
dependencies : [gobject_dep, gmodule_dep, glib_dep, mathlib] + platform_deps,
dependencies : [gobject_dep, gmodule_dep, glib_dep, mathlib, unwind_dep, dw_dep] + platform_deps,
vs_module_defs: vs_module_defs_dir + 'libgstreamer.def',
)
libgst = libgst_shared
......
......@@ -260,6 +260,27 @@ if cc.has_function('strsignal', prefix : '#include <string.h>')
cdata.set('HAVE_DECL_STRSIGNAL', 1)
endif
unwind_dep = dependency('libunwind', required : false)
dw_dep = dependency('libdw', required: false)
if unwind_dep.found()
cdata.set('HAVE_UNWIND', 1)
if dw_dep.found()
cdata.set('HAVE_DW', 1)
else
message('Support for backtraces is partial only.')
endif
else
if cc.has_function('backtrace')
cdata.set('HAVE_BACKTRACE', 1)
else
message('NO backtraces support.')
endif
endif
if cc.has_header('execinfo.h') and cc.has_function('backtrace', prefix : '#include <execinfo.h>')
cdata.set('HAVE_BACKTRACE', 1)
endif
configure_file(input : 'config.h.meson',
output : 'config.h',
configuration : cdata)
......
......@@ -12,15 +12,6 @@ endif
tracers_args = gst_c_args + ['-DGST_USE_UNSTABLE_API']
unwind_dep = dependency('libunwind', required : false)
if unwind_dep.found()
tracers_args += ['-DHAVE_UNWIND']
endif
if cc.has_header('execinfo.h') and cc.has_function('backtrace', prefix : '#include <execinfo.h>')
tracers_args += ['-DHAVE_BACKTRACE']
endif
gst_tracers = library('gstcoretracers',
gst_tracers_sources,
c_args : tracers_args,
......
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