reattach to the syslog-ng console from syslog-ng-ctl

lib/CMakeLists.txt

@@ -80,6 +80,7 @@ set (LIB_HEADERS
  atomic-gssize.h
  block-ref-parser.h
  cache.h
+ console.h
  cfg.h
  cfg-lexer.h
  cfg-lexer-subst.h
@@ -179,6 +180,7 @@ set(LIB_SOURCES
  apphook.c
  block-ref-parser.c
  cache.c
+ console.c
  cfg.c
  cfg-args.c
  cfg-block.c

lib/Makefile.am

@@ -97,6 +97,7 @@ pkginclude_HEADERS += \
  lib/atomic-gssize.h \
  lib/block-ref-parser.h \
  lib/cache.h \
+ lib/console.h \
  lib/cfg.h \
  lib/cfg-grammar.h \
  lib/cfg-grammar-internal.h \
@@ -195,6 +196,7 @@ lib_libsyslog_ng_la_SOURCES = \
  lib/apphook.c \
  lib/block-ref-parser.c \
  lib/cache.c \
+ lib/console.c \
  lib/cfg.c \
  lib/cfg-args.c \
  lib/cfg-block.c \

lib/console.c

@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2002-2012 Balabit
+ * Copyright (c) 1998-2012 Balázs Scheidler
+ * Copyright (c) 2024 Balázs Scheidler <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As an additional exemption you are allowed to compile & link against the
+ * OpenSSL libraries as published by the OpenSSL project. See the file
+ * COPYING for details.
+ *
+ */
+#include "console.h"
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+
+GMutex console_lock;
+gboolean console_present = FALSE;
+gboolean using_initial_console = TRUE;
+
+/* NOTE: this is not synced with any changes and is just an indication whether we have a console */
+gboolean
+console_is_present(gboolean exclude_initial)
+{
+ gboolean result;
+ /* the lock only serves a memory barrier but is not a real synchronization */
+ g_mutex_lock(&console_lock);
+ if (exclude_initial && using_initial_console)
+ result = FALSE;
+ else
+ result = console_present;
+ g_mutex_unlock(&console_lock);
+ return result;
+}
+
+/* set the current console to be our current stdin/out/err after we start up */
+void
+console_acquire_from_stdio(void)
+{
+ g_assert(!console_is_present(FALSE));
+
+ g_mutex_lock(&console_lock);
+ console_present = TRUE;
+ g_mutex_unlock(&console_lock);
+}
+
+/* re-acquire a console after startup using an array of fds */
+void
+console_acquire_from_fds(gint fds[3])
+{
+ const gchar *takeover_message_on_old_console = "[Console taken over, no further output here]\n";
+ g_assert(!console_is_present(TRUE));
+
+ if (using_initial_console)
+ {
+ (void) write(1, takeover_message_on_old_console, strlen(takeover_message_on_old_console));
+ }
+
+ g_mutex_lock(&console_lock);
+
+ dup2(fds[0], STDIN_FILENO);
+ dup2(fds[1], STDOUT_FILENO);
+ dup2(fds[2], STDERR_FILENO);
+
+ console_present = TRUE;
+ using_initial_console = FALSE;
+ g_mutex_unlock(&console_lock);
+}
+
+/**
+ * console_release:
+ *
+ * Use /dev/null as input/output/error. This function is idempotent, can be
+ * called any number of times without harm.
+ **/
+void
+console_release(void)
+{
+ gint devnull_fd;
+
+ g_mutex_lock(&console_lock);
+
+ if (!console_present)
+ goto exit;
+
+ devnull_fd = open("/dev/null", O_RDONLY);
+ if (devnull_fd >= 0)
+ {
+ dup2(devnull_fd, STDIN_FILENO);
+ close(devnull_fd);
+ }
+ devnull_fd = open("/dev/null", O_WRONLY);
+ if (devnull_fd >= 0)
+ {
+ dup2(devnull_fd, STDOUT_FILENO);
+ dup2(devnull_fd, STDERR_FILENO);
+ close(devnull_fd);
+ }
+ clearerr(stdin);
+ clearerr(stdout);
+ clearerr(stderr);
+ console_present = FALSE;
+ using_initial_console = FALSE;
+
+exit:
+ g_mutex_unlock(&console_lock);
+}
+
+void
+console_global_init(void)
+{
+ g_mutex_init(&console_lock);
+}
+
+void
+console_global_deinit(void)
+{
+ g_mutex_clear(&console_lock);
+}

lib/console.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2002-2012 Balabit
+ * Copyright (c) 1998-2012 Balázs Scheidler
+ * Copyright (c) 2024 Balázs Scheidler <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As an additional exemption you are allowed to compile & link against the
+ * OpenSSL libraries as published by the OpenSSL project. See the file
+ * COPYING for details.
+ *
+ */
+#ifndef SYSLOG_NG_CONSOLE_H_INCLUDED
+#define SYSLOG_NG_CONSOLE_H_INCLUDED
+
+#include "syslog-ng.h"
+
+gboolean console_is_present(gboolean exclude_initial);
+void console_acquire_from_fds(gint fds[3]);
+void console_acquire_from_stdio(void);
+void console_release(void);
+
+void console_global_init(void);
+void console_global_deinit(void);
+
+#endif

lib/control/control-command-thread.c

@@ -27,6 +27,7 @@
 #include "messages.h"
 #include "secret-storage/secret-storage.h"
 #include "scratch-buffers.h"
+#include "apphook.h"
 #include <iv_event.h>
 
 struct _ControlCommandThread
@@ -44,6 +45,12 @@ struct _ControlCommandThread
  struct iv_event thread_finished;
 };
 
+gboolean
+control_command_thread_relates_to_connection(ControlCommandThread *self, ControlConnection *cc)
+{
+ return self->connection == cc;
+}
+
 static void
 _on_thread_finished(gpointer user_data)
 {
@@ -64,7 +71,7 @@ _thread(gpointer user_data)
  ControlCommandThread *self = (ControlCommandThread *) user_data;
 
  iv_init();
- scratch_buffers_allocator_init();
+ app_thread_start();
 
  msg_debug("Control command thread has started",
  evt_tag_str("control_command", self->command->str));
@@ -82,8 +89,8 @@ _thread(gpointer user_data)
  evt_tag_str("control_command", self->command->str));
 
  scratch_buffers_explicit_gc();
- scratch_buffers_allocator_deinit();
  control_command_thread_unref(self);
+ app_thread_stop();
  iv_deinit();
 }
 

lib/control/control-command-thread.h

@@ -27,6 +27,8 @@
 
 #include "control.h"
 
+gboolean control_command_thread_relates_to_connection(ControlCommandThread *self, ControlConnection *cc);
+
 void control_command_thread_run(ControlCommandThread *self);
 void control_command_thread_cancel(ControlCommandThread *self);
 const gchar *control_command_thread_get_command(ControlCommandThread *self);

lib/control/control-connection.c

@@ -36,6 +36,14 @@ _g_string_destroy(gpointer user_data)
  g_string_free(str, TRUE);
 }
 
+gboolean
+control_connection_get_attached_fds(ControlConnection *self, gint *fds, gsize *num_fds)
+{
+ if (self->get_attached_fds)
+ return self->get_attached_fds(self, fds, num_fds);
+ return FALSE;
+}
+
 static void
 _control_connection_free(ControlConnection *self)
 {
@@ -215,7 +223,7 @@ control_connection_io_input(void *s)
  }
  else if (rc == 0)
  {
- msg_debug("EOF on control channel, closing connection");
+ msg_trace("EOF on control channel, closing connection");
  goto destroy_connection;
  }
  else

lib/control/control-connection.h

@@ -41,6 +41,7 @@ struct _ControlConnection
  GString *output_buffer;
  gsize pos;
  ControlServer *server;
+ gboolean (*get_attached_fds)(ControlConnection *self, gint *fds, gsize *num_fds);
  gboolean (*run_command)(ControlConnection *self, ControlCommand *command_desc, GString *command_string);
  int (*read)(ControlConnection *self, gpointer buffer, gsize size);
  int (*write)(ControlConnection *self, gpointer buffer, gsize size);
@@ -56,6 +57,7 @@ struct _ControlConnection
 
 };
 
+gboolean control_connection_get_attached_fds(ControlConnection *self, gint *fds, gsize *num_fds);
 gboolean control_connection_run_command(ControlConnection *self, GString *command_string);
 void control_connection_send_reply(ControlConnection *self, GString *reply);
 void control_connection_send_batched_reply(ControlConnection *self, GString *reply);