signal.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2001, 2002, 2006 GNUnet e.V.
 
     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.
 
     GNUnet 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
     Affero General Public License for more details.
 
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_util_lib.h"
 
#define LOG(kind, ...) GNUNET_log_from (kind, "util-signal", __VA_ARGS__)
 
 
struct GNUNET_SIGNAL_Context
{
  struct GNUNET_SIGNAL_Context *next;
 
  struct GNUNET_SIGNAL_Context *prev;
 
  int sig;
 
  GNUNET_SIGNAL_Handler method;
 
  struct sigaction oldsig;
};
 
static struct GNUNET_SIGNAL_Context *sc_head;
 
static struct GNUNET_SIGNAL_Context *sc_tail;
 
struct GNUNET_SIGNAL_Context *
GNUNET_SIGNAL_handler_install (int signum, GNUNET_SIGNAL_Handler handler)
{
  struct GNUNET_SIGNAL_Context *ret;
 
  struct sigaction sig;
 
  ret = GNUNET_new (struct GNUNET_SIGNAL_Context);
  ret->sig = signum;
  ret->method = handler;
 
  memset (&sig, 0, sizeof(sig));
  sig.sa_handler = (void *) handler;
  sigemptyset (&sig.sa_mask);
#ifdef SA_INTERRUPT
  sig.sa_flags = SA_INTERRUPT;  /* SunOS */
#else
  sig.sa_flags = SA_RESTART;
#endif
  sigaction (signum, &sig, &ret->oldsig);
 
  GNUNET_CONTAINER_DLL_insert_tail (sc_head, sc_tail, ret);
  return ret;
}
 
 
void
GNUNET_SIGNAL_handler_uninstall (struct GNUNET_SIGNAL_Context *ctx)
{
  struct sigaction sig;
 
  sigemptyset (&sig.sa_mask);
  sigaction (ctx->sig, &ctx->oldsig, &sig);
 
  GNUNET_CONTAINER_DLL_remove (sc_head, sc_tail, ctx);
  GNUNET_free (ctx);
}
 
 
void
GNUNET_SIGNAL_raise (const int sig)
{
  struct GNUNET_SIGNAL_Context *ctx;
 
  for (ctx = sc_head; NULL != ctx; ctx = ctx->next)
  {
    if (sig != ctx->sig)
      continue;
    if (NULL == ctx->method)
      continue;
    ctx->method ();
  }
}