mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-25 11:03:42 +08:00
bbc1cfa669
appropriately, and that GNUmakefile and the MSVC++ project file define it apppriately, as we do with libpcap, rather than defining it in "interface.h". Undo the rcsid-shuffling and addition of extra #includes, as we no longer need to arrange that "interface.h" be included before using _U_ in an RCS ID or copyright.
94 lines
3.4 KiB
C
94 lines
3.4 KiB
C
/*
|
|
* Copyright (c) 1997
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that: (1) source code distributions
|
|
* retain the above copyright notice and this paragraph in its entirety, (2)
|
|
* distributions including binary code include the above copyright notice and
|
|
* this paragraph in its entirety in the documentation or other materials
|
|
* provided with the distribution, and (3) all advertising materials mentioning
|
|
* features or use of this software display the following acknowledgement:
|
|
* ``This product includes software developed by the University of California,
|
|
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
|
|
* the University nor the names of its contributors may be used to endorse
|
|
* or promote products derived from this software without specific prior
|
|
* written permission.
|
|
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
|
|
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static const char rcsid[] _U_ =
|
|
"@(#) $Header: /tcpdump/master/tcpdump/setsignal.c,v 1.11 2003-11-16 09:36:42 guy Exp $ (LBL)";
|
|
#endif
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <tcpdump-stdinc.h>
|
|
|
|
#include <signal.h>
|
|
#ifdef HAVE_SIGACTION
|
|
#include <string.h>
|
|
#endif
|
|
|
|
#ifdef HAVE_OS_PROTO_H
|
|
#include "os-proto.h"
|
|
#endif
|
|
|
|
#include "setsignal.h"
|
|
|
|
/*
|
|
* An OS-independent signal() with, whenever possible, partial BSD
|
|
* semantics, i.e. the signal handler is restored following service
|
|
* of the signal, but system calls are *not* restarted, so that if
|
|
* "pcap_breakloop()" is called in a signal handler in a live capture,
|
|
* the read/recvfrom/whatever in the live capture doesn't get restarted,
|
|
* it returns -1 and sets "errno" to EINTR, so we can break out of the
|
|
* live capture loop.
|
|
*
|
|
* We use "sigaction()" if available. We don't specify that the signal
|
|
* should restart system calls, so that should always do what we want.
|
|
*
|
|
* Otherwise, if "sigset()" is available, it probably has BSD semantics
|
|
* while "signal()" has traditional semantics, so we use "sigset()"; it
|
|
* might cause system calls to be restarted for the signal, however.
|
|
* I don't know whether, in any systems where it did cause system calls to
|
|
* be restarted, there was a way to ask it not to do so; there may no
|
|
* longer be any interesting systems without "sigaction()", however,
|
|
* and, if there are, they might have "sigvec()" with SV_INTERRUPT
|
|
* (which I think first appeared in 4.3BSD).
|
|
*
|
|
* Otherwise, we use "signal()" - which means we might get traditional
|
|
* semantics, wherein system calls don't get restarted *but* the
|
|
* signal handler is reset to SIG_DFL and the signal is not blocked,
|
|
* so that a subsequent signal would kill the process immediately.
|
|
*
|
|
* Did I mention that signals suck? At least in POSIX-compliant systems
|
|
* they suck far less, as those systems have "sigaction()".
|
|
*/
|
|
RETSIGTYPE
|
|
(*setsignal (int sig, RETSIGTYPE (*func)(int)))(int)
|
|
{
|
|
#ifdef HAVE_SIGACTION
|
|
struct sigaction old, new;
|
|
|
|
memset(&new, 0, sizeof(new));
|
|
new.sa_handler = func;
|
|
if (sigaction(sig, &new, &old) < 0)
|
|
return (SIG_ERR);
|
|
return (old.sa_handler);
|
|
|
|
#else
|
|
#ifdef HAVE_SIGSET
|
|
return (sigset(sig, func));
|
|
#else
|
|
return (signal(sig, func));
|
|
#endif
|
|
#endif
|
|
}
|
|
|