lib/signals.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2011, 2012, 2013 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "signals.h"
  19 #include <errno.h>
  20 #include <limits.h>
  21 #include <signal.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include "openvswitch/poll-loop.h"
  25 #include "socket-util.h"
  26 #include "openvswitch/type-props.h"
  27 #include "util.h"
  28 #include "openvswitch/vlog.h"
  29
  30 VLOG_DEFINE_THIS_MODULE(signals);
  31
  32 #if defined(_NSIG)
  33 #define N_SIGNALS _NSIG
  34 #elif defined(NSIG)
  35 #define N_SIGNALS NSIG
  36 #else
  37 /* We could try harder to get the maximum signal number, but in practice we
  38  * only care about SIGHUP, which is normally signal 1 anyway. */
  39 #define N_SIGNALS 32
  40 #endif
  41
  42 /* Returns the name of signal 'signum' as a string.  The return value is either
  43  * a statically allocated constant string or the 'bufsize'-byte buffer
  44  * 'namebuf'.  'bufsize' should be at least SIGNAL_NAME_BUFSIZE.
  45  *
  46  * The string is probably a (possibly multi-word) description of the signal
  47  * (e.g. "Hangup") instead of just the stringified version of the macro
  48  * (e.g. "SIGHUP"). */
  49 const char *
  50 signal_name(int signum, char *namebuf, size_t bufsize)
  51 {
  52 #if HAVE_DECL_SYS_SIGLIST
  53     if (signum >= 0 && signum < N_SIGNALS) {
  54         const char *name = sys_siglist[signum];
  55         if (name) {
  56             return name;
  57         }
  58     }
  59 #endif
  60
  61     snprintf(namebuf, bufsize, "signal %d", signum);
  62     return namebuf;
  63 }
  64
  65 void
  66 xsigaction(int signum, const struct sigaction *new, struct sigaction *old)
  67 {
  68     if (sigaction(signum, new, old)) {
  69         char namebuf[SIGNAL_NAME_BUFSIZE];
  70
  71         VLOG_FATAL("sigaction(%s) failed (%s)",
  72                    signal_name(signum, namebuf, sizeof namebuf),
  73                    ovs_strerror(errno));
  74     }
  75 }