gimp/app/core/gimpbacktrace-linux.c

726 lines
17 KiB
C

/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995-1999 Spencer Kimball and Peter Mattis
*
* gimpbacktrace-linux.c
* Copyright (C) 2018 Ell
*
* 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
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 <https://www.gnu.org/licenses/>.
*/
#define _GNU_SOURCE
#include "config.h"
#include <gio/gio.h>
#include "gimpbacktrace-backend.h"
#ifdef GIMP_BACKTRACE_BACKEND_LINUX
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <signal.h>
#include <execinfo.h>
#include <dlfcn.h>
#include <string.h>
#include <stdio.h>
#ifdef HAVE_LIBBACKTRACE
#include <backtrace.h>
#endif
#ifdef HAVE_LIBUNWIND
#define UNW_LOCAL_ONLY
#include <libunwind.h>
#endif
#include "core-types.h"
#include "gimpbacktrace.h"
#define MAX_N_THREADS 256
#define MAX_N_FRAMES 256
#define MAX_THREAD_NAME_SIZE 32
#define N_SKIPPED_FRAMES 2
#define MAX_WAIT_TIME (G_TIME_SPAN_SECOND / 20)
#define BACKTRACE_SIGNAL SIGUSR1
typedef struct _GimpBacktraceThread GimpBacktraceThread;
struct _GimpBacktraceThread
{
pid_t tid;
gchar name[MAX_THREAD_NAME_SIZE];
gchar state;
guintptr frames[MAX_N_FRAMES];
gint n_frames;
};
struct _GimpBacktrace
{
GimpBacktraceThread *threads;
gint n_threads;
};
/* local function prototypes */
static inline gint gimp_backtrace_normalize_frame (GimpBacktrace *backtrace,
gint thread,
gint frame);
static gint gimp_backtrace_enumerate_threads (gboolean include_current_thread,
pid_t *threads,
gint size);
static void gimp_backtrace_read_thread_name (pid_t tid,
gchar *name,
gint size);
static gchar gimp_backtrace_read_thread_state (pid_t tid);
static void gimp_backtrace_signal_handler (gint signum);
/* static variables */
static GMutex mutex;
static gint n_initializations;
static gboolean initialized;
static struct sigaction orig_action;
static pid_t blacklisted_threads[MAX_N_THREADS];
static gint n_blacklisted_threads;
static GimpBacktrace *handler_backtrace;
static gint handler_n_remaining_threads;
static gint handler_lock;
#ifdef HAVE_LIBBACKTRACE
static struct backtrace_state *backtrace_state;
#endif
static const gchar * const blacklisted_thread_names[] =
{
"gmain",
"threaded-ml"
};
/* private functions */
static inline gint
gimp_backtrace_normalize_frame (GimpBacktrace *backtrace,
gint thread,
gint frame)
{
if (frame >= 0)
return frame + N_SKIPPED_FRAMES;
else
return backtrace->threads[thread].n_frames + frame;
}
static gint
gimp_backtrace_enumerate_threads (gboolean include_current_thread,
pid_t *threads,
gint size)
{
DIR *dir;
struct dirent *dirent;
pid_t tid;
gint n_threads;
dir = opendir ("/proc/self/task");
if (! dir)
return 0;
tid = syscall (SYS_gettid);
n_threads = 0;
while (n_threads < size && (dirent = readdir (dir)))
{
pid_t id = g_ascii_strtoull (dirent->d_name, NULL, 10);
if (id)
{
if (! include_current_thread && id == tid)
id = 0;
}
if (id)
{
gint i;
for (i = 0; i < n_blacklisted_threads; i++)
{
if (id == blacklisted_threads[i])
{
id = 0;
break;
}
}
}
if (id)
threads[n_threads++] = id;
}
closedir (dir);
return n_threads;
}
static void
gimp_backtrace_read_thread_name (pid_t tid,
gchar *name,
gint size)
{
gchar filename[64];
gint fd;
if (size <= 0)
return;
name[0] = '\0';
g_snprintf (filename, sizeof (filename),
"/proc/self/task/%llu/comm",
(unsigned long long) tid);
fd = open (filename, O_RDONLY);
if (fd >= 0)
{
gint n = read (fd, name, size);
if (n > 0)
name[n - 1] = '\0';
close (fd);
}
}
static gchar
gimp_backtrace_read_thread_state (pid_t tid)
{
gchar buffer[64];
gint fd;
gchar state = '\0';
g_snprintf (buffer, sizeof (buffer),
"/proc/self/task/%llu/stat",
(unsigned long long) tid);
fd = open (buffer, O_RDONLY);
if (fd >= 0)
{
gint n = read (fd, buffer, sizeof (buffer));
if (n > 0)
buffer[n - 1] = '\0';
sscanf (buffer, "%*d %*s %c", &state);
close (fd);
}
return state;
}
static void
gimp_backtrace_signal_handler (gint signum)
{
GimpBacktrace *curr_backtrace;
gint lock;
do
{
lock = g_atomic_int_get (&handler_lock);
if (lock < 0)
continue;
}
while (! g_atomic_int_compare_and_exchange (&handler_lock, lock, lock + 1));
curr_backtrace = g_atomic_pointer_get (&handler_backtrace);
if (curr_backtrace)
{
pid_t tid = syscall (SYS_gettid);
gint i;
for (i = 0; i < curr_backtrace->n_threads; i++)
{
GimpBacktraceThread *thread = &curr_backtrace->threads[i];
if (thread->tid == tid)
{
thread->n_frames = backtrace ((gpointer *) thread->frames,
MAX_N_FRAMES);
g_atomic_int_dec_and_test (&handler_n_remaining_threads);
break;
}
}
}
g_atomic_int_dec_and_test (&handler_lock);
}
/* public functions */
void
gimp_backtrace_init (void)
{
#ifdef HAVE_LIBBACKTRACE
backtrace_state = backtrace_create_state (NULL, 0, NULL, NULL);
#endif
}
gboolean
gimp_backtrace_start (void)
{
g_mutex_lock (&mutex);
if (n_initializations == 0)
{
struct sigaction action = {};
action.sa_handler = gimp_backtrace_signal_handler;
action.sa_flags = SA_RESTART;
sigemptyset (&action.sa_mask);
if (sigaction (BACKTRACE_SIGNAL, &action, &orig_action) == 0)
{
pid_t *threads;
gint n_threads;
gint i;
n_blacklisted_threads = 0;
threads = g_new (pid_t, MAX_N_THREADS);
n_threads = gimp_backtrace_enumerate_threads (TRUE,
threads, MAX_N_THREADS);
for (i = 0; i < n_threads; i++)
{
gchar name[MAX_THREAD_NAME_SIZE];
gint j;
gimp_backtrace_read_thread_name (threads[i],
name, MAX_THREAD_NAME_SIZE);
for (j = 0; j < G_N_ELEMENTS (blacklisted_thread_names); j++)
{
if (! strcmp (name, blacklisted_thread_names[j]))
{
blacklisted_threads[n_blacklisted_threads++] = threads[i];
}
}
}
g_free (threads);
initialized = TRUE;
}
}
n_initializations++;
g_mutex_unlock (&mutex);
return initialized;
}
void
gimp_backtrace_stop (void)
{
g_return_if_fail (n_initializations > 0);
g_mutex_lock (&mutex);
n_initializations--;
if (n_initializations == 0 && initialized)
{
if (sigaction (BACKTRACE_SIGNAL, &orig_action, NULL) < 0)
g_warning ("failed to restore original backtrace signal handler");
initialized = FALSE;
}
g_mutex_unlock (&mutex);
}
GimpBacktrace *
gimp_backtrace_new (gboolean include_current_thread)
{
GimpBacktrace *backtrace;
pid_t pid;
pid_t *threads;
gint n_threads;
gint64 start_time;
gint i;
if (! initialized)
return NULL;
pid = getpid ();
threads = g_new (pid_t, MAX_N_THREADS);
n_threads = gimp_backtrace_enumerate_threads (include_current_thread,
threads, MAX_N_THREADS);
if (n_threads == 0)
{
g_free (threads);
return NULL;
}
g_mutex_lock (&mutex);
backtrace = g_slice_new (GimpBacktrace);
backtrace->threads = g_new (GimpBacktraceThread, n_threads);
backtrace->n_threads = n_threads;
while (! g_atomic_int_compare_and_exchange (&handler_lock, 0, -1));
g_atomic_pointer_set (&handler_backtrace, backtrace);
g_atomic_int_set (&handler_n_remaining_threads, n_threads);
g_atomic_int_set (&handler_lock, 0);
for (i = 0; i < n_threads; i++)
{
GimpBacktraceThread *thread = &backtrace->threads[i];
thread->tid = threads[i];
thread->n_frames = 0;
gimp_backtrace_read_thread_name (thread->tid,
thread->name, MAX_THREAD_NAME_SIZE);
thread->state = gimp_backtrace_read_thread_state (thread->tid);
syscall (SYS_tgkill, pid, threads[i], BACKTRACE_SIGNAL);
}
g_free (threads);
start_time = g_get_monotonic_time ();
while (g_atomic_int_get (&handler_n_remaining_threads) > 0)
{
gint64 time = g_get_monotonic_time ();
if (time - start_time > MAX_WAIT_TIME)
break;
g_usleep (1000);
}
while (! g_atomic_int_compare_and_exchange (&handler_lock, 0, -1));
g_atomic_pointer_set (&handler_backtrace, NULL);
g_atomic_int_set (&handler_lock, 0);
#if 0
if (handler_n_remaining_threads > 0)
{
gint j = 0;
for (i = 0; i < n_threads; i++)
{
if (backtrace->threads[i].n_frames == 0)
{
if (n_blacklisted_threads < MAX_N_THREADS)
{
blacklisted_threads[n_blacklisted_threads++] =
backtrace->threads[i].tid;
}
}
else
{
if (j < i)
backtrace->threads[j] = backtrace->threads[i];
j++;
}
}
n_threads = j;
}
#endif
g_mutex_unlock (&mutex);
if (n_threads == 0)
{
gimp_backtrace_free (backtrace);
return NULL;
}
return backtrace;
}
void
gimp_backtrace_free (GimpBacktrace *backtrace)
{
if (! backtrace)
return;
g_free (backtrace->threads);
g_slice_free (GimpBacktrace, backtrace);
}
gint
gimp_backtrace_get_n_threads (GimpBacktrace *backtrace)
{
g_return_val_if_fail (backtrace != NULL, 0);
return backtrace->n_threads;
}
guintptr
gimp_backtrace_get_thread_id (GimpBacktrace *backtrace,
gint thread)
{
g_return_val_if_fail (backtrace != NULL, 0);
g_return_val_if_fail (thread >= 0 && thread < backtrace->n_threads, 0);
return backtrace->threads[thread].tid;
}
const gchar *
gimp_backtrace_get_thread_name (GimpBacktrace *backtrace,
gint thread)
{
g_return_val_if_fail (backtrace != NULL, NULL);
g_return_val_if_fail (thread >= 0 && thread < backtrace->n_threads, NULL);
if (backtrace->threads[thread].name[0])
return backtrace->threads[thread].name;
else
return NULL;
}
gboolean
gimp_backtrace_is_thread_running (GimpBacktrace *backtrace,
gint thread)
{
g_return_val_if_fail (backtrace != NULL, FALSE);
g_return_val_if_fail (thread >= 0 && thread < backtrace->n_threads, FALSE);
return backtrace->threads[thread].state == 'R';
}
gint
gimp_backtrace_find_thread_by_id (GimpBacktrace *backtrace,
guintptr thread_id,
gint thread_hint)
{
pid_t tid = thread_id;
gint i;
g_return_val_if_fail (backtrace != NULL, -1);
if (thread_hint >= 0 &&
thread_hint < backtrace->n_threads &&
backtrace->threads[thread_hint].tid == tid)
{
return thread_hint;
}
for (i = 0; i < backtrace->n_threads; i++)
{
if (backtrace->threads[i].tid == tid)
return i;
}
return -1;
}
gint
gimp_backtrace_get_n_frames (GimpBacktrace *backtrace,
gint thread)
{
g_return_val_if_fail (backtrace != NULL, 0);
g_return_val_if_fail (thread >= 0 && thread < backtrace->n_threads, 0);
return MAX (backtrace->threads[thread].n_frames - N_SKIPPED_FRAMES, 0);
}
guintptr
gimp_backtrace_get_frame_address (GimpBacktrace *backtrace,
gint thread,
gint frame)
{
g_return_val_if_fail (backtrace != NULL, 0);
g_return_val_if_fail (thread >= 0 && thread < backtrace->n_threads, 0);
frame = gimp_backtrace_normalize_frame (backtrace, thread, frame);
g_return_val_if_fail (frame >= N_SKIPPED_FRAMES &&
frame < backtrace->threads[thread].n_frames, 0);
return backtrace->threads[thread].frames[frame];
}
#ifdef HAVE_LIBBACKTRACE
static void
gimp_backtrace_syminfo_callback (GimpBacktraceAddressInfo *info,
guintptr pc,
const gchar *symname,
guintptr symval,
guintptr symsize)
{
if (symname)
g_strlcpy (info->symbol_name, symname, sizeof (info->symbol_name));
info->symbol_address = symval;
}
static gint
gimp_backtrace_pcinfo_callback (GimpBacktraceAddressInfo *info,
guintptr pc,
const gchar *filename,
gint lineno,
const gchar *function)
{
if (function)
g_strlcpy (info->symbol_name, function, sizeof (info->symbol_name));
if (filename)
g_strlcpy (info->source_file, filename, sizeof (info->source_file));
info->source_line = lineno;
return 0;
}
#endif /* HAVE_LIBBACKTRACE */
gboolean
gimp_backtrace_get_address_info (guintptr address,
GimpBacktraceAddressInfo *info)
{
Dl_info dl_info;
gboolean result = FALSE;
g_return_val_if_fail (info != NULL, FALSE);
info->object_name[0] = '\0';
info->symbol_name[0] = '\0';
info->symbol_address = 0;
info->source_file[0] = '\0';
info->source_line = 0;
if (dladdr ((gpointer) address, &dl_info))
{
if (dl_info.dli_fname)
{
g_strlcpy (info->object_name, dl_info.dli_fname,
sizeof (info->object_name));
}
if (dl_info.dli_sname)
{
g_strlcpy (info->symbol_name, dl_info.dli_sname,
sizeof (info->symbol_name));
}
info->symbol_address = (guintptr) dl_info.dli_saddr;
result = TRUE;
}
#ifdef HAVE_LIBBACKTRACE
if (backtrace_state)
{
backtrace_syminfo (
backtrace_state, address,
(backtrace_syminfo_callback) gimp_backtrace_syminfo_callback,
NULL,
info);
backtrace_pcinfo (
backtrace_state, address,
(backtrace_full_callback) gimp_backtrace_pcinfo_callback,
NULL,
info);
result = TRUE;
}
#endif /* HAVE_LIBBACKTRACE */
#ifdef HAVE_LIBUNWIND
/* we use libunwind to get the symbol name, when available, even if dladdr() or
* libbacktrace already found one, since it provides more descriptive names in
* some cases, and, in particular, full symbol names for C++ lambdas.
*
* note that, in some cases, this can result in a discrepancy between the
* symbol name, and the corresponding source location.
*/
#if 0
if (! info->symbol_name[0])
#endif
{
unw_context_t context = {};
unw_cursor_t cursor;
unw_word_t offset;
if (unw_init_local (&cursor, &context) == 0 &&
unw_set_reg (&cursor, UNW_REG_IP, address) == 0 &&
unw_get_proc_name (&cursor,
info->symbol_name, sizeof (info->symbol_name),
&offset) == 0)
{
info->symbol_address = address - offset;
result = TRUE;
}
}
#endif /* HAVE_LIBUNWIND */
return result;
}
#endif /* GIMP_BACKTRACE_BACKEND_LINUX */