Syslog ng ctl attach debugger

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 <balazs.scheidler@axoflow.com>
+ *
+ * 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 <balazs.scheidler@axoflow.com>
+ *
+ * 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);