libsysprof: provide unwind pipe from client

We don't need a socketpair for this. Additionally, things seem to work
better from the service when the client provides the pipe. Otherwise, when
running as a dbus service I often have issues with things getting closed
out from under us.
This commit is contained in:
Christian Hergert
2024-11-13 15:40:52 -08:00
parent 8995c65444
commit 083b2edbc0
3 changed files with 48 additions and 65 deletions

View File

@ -20,6 +20,8 @@
#include "config.h"
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/eventfd.h>
@ -62,7 +64,8 @@ struct _SysprofUserSampler
{
SysprofInstrument parent_instance;
GArray *perf_fds;
int capture_fd;
int capture_fd_read;
int capture_fd_write;
int event_fd;
guint stack_size;
};
@ -289,17 +292,14 @@ call_unwind_cb (GObject *object,
{
g_autoptr(DexPromise) promise = user_data;
g_autoptr(GUnixFDList) out_fd_list = NULL;
g_autoptr(GVariant) out_capture_fd = NULL;
g_autofd int capture_fd = -1;
GError *error = NULL;
g_assert (IPC_IS_UNWINDER (object));
g_assert (G_IS_ASYNC_RESULT (result));
g_assert (DEX_IS_PROMISE (promise));
if (ipc_unwinder_call_unwind_finish (IPC_UNWINDER (object), &out_capture_fd, &out_fd_list, result, &error) &&
-1 != (capture_fd = g_unix_fd_list_get (out_fd_list, g_variant_get_handle (out_capture_fd), &error)))
promise_resolve_fd (promise, g_steal_fd (&capture_fd));
if (ipc_unwinder_call_unwind_finish (IPC_UNWINDER (object), &out_fd_list, result, &error))
dex_promise_resolve_boolean (promise, TRUE);
else
dex_promise_reject (promise, error);
}
@ -420,31 +420,26 @@ sysprof_user_sampler_prepare_fiber (gpointer user_data)
{
g_autoptr(DexPromise) promise = dex_promise_new ();
int event_fd_handle = g_unix_fd_list_append (fd_list, prepare->sampler->event_fd, NULL);
g_autofd int fd = -1;
int capture_fd_handle = g_unix_fd_list_append (fd_list, prepare->sampler->capture_fd_write, NULL);
ipc_unwinder_call_unwind (unwinder,
prepare->stack_size,
g_variant_builder_end (&builder),
g_variant_new_handle (event_fd_handle),
g_variant_new_handle (capture_fd_handle),
fd_list,
NULL,
call_unwind_cb,
dex_ref (promise));
fd = await_fd (dex_ref (promise), &error);
if (fd == -1)
if (!dex_await (dex_ref (promise), &error))
{
_sysprof_recording_diagnostic (prepare->recording,
"Sampler",
"Failed to setup user-space unwinder: %s",
"Failed to setup thread unwinder: %s",
error->message);
g_clear_error (&error);
}
else
{
prepare->sampler->capture_fd = g_steal_fd (&fd);
}
}
}
@ -506,21 +501,26 @@ sysprof_user_sampler_record_fiber (gpointer user_data)
writer = _sysprof_recording_writer (record->recording);
sysprof_user_sampler_ioctl (record->sampler, TRUE);
if (record->sampler->capture_fd_read != -1)
{
sysprof_user_sampler_ioctl (record->sampler, TRUE);
g_debug ("Staring muxer for capture_fd");
muxer_source = sysprof_muxer_source_new (g_steal_fd (&record->sampler->capture_fd), writer);
g_source_set_static_name (muxer_source, "[stack-muxer]");
g_source_attach (muxer_source, NULL);
g_debug ("Staring muxer for capture_fd %d", record->sampler->capture_fd_read);
muxer_source = sysprof_muxer_source_new (g_steal_fd (&record->sampler->capture_fd_read), writer);
g_source_set_static_name (muxer_source, "[stack-muxer]");
g_source_attach (muxer_source, NULL);
if (!dex_await (dex_ref (record->cancellable), &error))
g_debug ("UserSampler shutting down for reason: %s", error->message);
if (!dex_await (dex_ref (record->cancellable), &error))
g_debug ("UserSampler shutting down for reason: %s", error->message);
write (record->sampler->event_fd, &exiting, sizeof exiting);
write (record->sampler->event_fd, &exiting, sizeof exiting);
g_source_destroy (muxer_source);
g_source_destroy (muxer_source);
sysprof_user_sampler_ioctl (record->sampler, FALSE);
sysprof_user_sampler_ioctl (record->sampler, FALSE);
}
else
g_warning ("No capture FD available for muxing");
return dex_future_new_for_boolean (TRUE);
}
@ -555,7 +555,8 @@ sysprof_user_sampler_finalize (GObject *object)
g_clear_pointer (&self->perf_fds, g_array_unref);
g_clear_fd (&self->capture_fd, NULL);
g_clear_fd (&self->capture_fd_read, NULL);
g_clear_fd (&self->capture_fd_write, NULL);
g_clear_fd (&self->event_fd, NULL);
G_OBJECT_CLASS (sysprof_user_sampler_parent_class)->finalize (object);
@ -577,9 +578,19 @@ sysprof_user_sampler_class_init (SysprofUserSamplerClass *klass)
static void
sysprof_user_sampler_init (SysprofUserSampler *self)
{
self->capture_fd = -1;
int fds[2];
self->event_fd = eventfd (0, EFD_CLOEXEC);
self->capture_fd_read = -1;
self->capture_fd_write = -1;
if (pipe2 (fds, O_CLOEXEC) == 0)
{
self->capture_fd_read = fds[0];
self->capture_fd_write = fds[1];
}
self->perf_fds = g_array_new (FALSE, FALSE, sizeof (int));
g_array_set_clear_func (self->perf_fds, close_fd);
}

View File

@ -24,6 +24,7 @@
#include "config.h"
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/prctl.h>
@ -71,19 +72,16 @@ ipc_unwinder_impl_handle_unwind (IpcUnwinder *unwinder,
GUnixFDList *fd_list,
guint stack_size,
GVariant *arg_perf_fds,
GVariant *arg_event_fd)
GVariant *arg_event_fd,
GVariant *arg_capture_fd)
{
g_autoptr(GSubprocessLauncher) launcher = NULL;
g_autoptr(GSubprocess) subprocess = NULL;
g_autoptr(GUnixFDList) out_fd_list = NULL;
g_autoptr(GPtrArray) argv = NULL;
g_autoptr(GError) error = NULL;
g_autofd int our_fd = -1;
g_autofd int their_fd = -1;
g_autofd int capture_fd = -1;
g_autofd int event_fd = -1;
GVariantIter iter;
int capture_fd_handle;
int pair[2];
int next_target_fd = 3;
int perf_fd_handle;
int cpu;
@ -116,13 +114,14 @@ ipc_unwinder_impl_handle_unwind (IpcUnwinder *unwinder,
g_ptr_array_add (argv, g_strdup (PACKAGE_LIBEXECDIR "/sysprof-live-unwinder"));
g_ptr_array_add (argv, g_strdup_printf ("--stack-size=%u", stack_size));
if (-1 == (event_fd = g_unix_fd_list_get (fd_list, g_variant_get_handle (arg_event_fd), &error)))
if (-1 == (event_fd = g_unix_fd_list_get (fd_list, g_variant_get_handle (arg_event_fd), &error)) ||
-1 == (capture_fd = g_unix_fd_list_get (fd_list, g_variant_get_handle (arg_capture_fd), &error)))
{
g_dbus_method_invocation_return_gerror (g_steal_pointer (&invocation), error);
return TRUE;
}
g_ptr_array_add (argv, g_strdup_printf ("--event-fd=%u", next_target_fd));
g_ptr_array_add (argv, g_strdup_printf ("--event-fd=%d", next_target_fd));
g_subprocess_launcher_take_fd (launcher, g_steal_fd (&event_fd), next_target_fd++);
g_variant_iter_init (&iter, arg_perf_fds);
@ -143,32 +142,8 @@ ipc_unwinder_impl_handle_unwind (IpcUnwinder *unwinder,
next_target_fd++);
}
g_subprocess_launcher_set_child_setup (launcher, child_setup, NULL, NULL);
if (socketpair (AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, pair) < 0)
{
int errsv = errno;
g_dbus_method_invocation_return_error_literal (g_steal_pointer (&invocation),
G_IO_ERROR,
g_io_error_from_errno (errsv),
g_strerror (errsv));
return TRUE;
}
our_fd = g_steal_fd (&pair[0]);
their_fd = g_steal_fd (&pair[1]);
out_fd_list = g_unix_fd_list_new ();
capture_fd_handle = g_unix_fd_list_append (out_fd_list, their_fd, &error);
if (capture_fd_handle < 0)
{
g_dbus_method_invocation_return_gerror (g_steal_pointer (&invocation), error);
return TRUE;
}
g_ptr_array_add (argv, g_strdup_printf ("--capture-fd=%d", next_target_fd));
g_subprocess_launcher_take_fd (launcher, g_steal_fd (&our_fd), next_target_fd++);
g_subprocess_launcher_take_fd (launcher, g_steal_fd (&capture_fd), next_target_fd++);
g_ptr_array_add (argv, NULL);
@ -182,10 +157,7 @@ ipc_unwinder_impl_handle_unwind (IpcUnwinder *unwinder,
g_message ("sysprof-live-unwinder started as process %s",
g_subprocess_get_identifier (subprocess));
ipc_unwinder_complete_unwind (unwinder,
g_steal_pointer (&invocation),
out_fd_list,
g_variant_new_handle (capture_fd_handle));
ipc_unwinder_complete_unwind (unwinder, g_steal_pointer (&invocation), NULL);
g_subprocess_wait_check_async (subprocess,
NULL,

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@ -17,7 +17,7 @@
<arg type="u" name="stack_size" direction="in"/>
<arg type="a(hi)" name="perf_fds" direction="in"/>
<arg type="h" name="event_fd" direction="in"/>
<arg type="h" name="capture_fd" direction="out"/>
<arg type="h" name="capture_fd" direction="in"/>
</method>
</interface>
</node>