12949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project/* 22949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Copyright (c) 1997 32949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * The Regents of the University of California. All rights reserved. 42949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * 52949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Redistribution and use in source and binary forms, with or without 62949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * modification, are permitted provided that: (1) source code distributions 72949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * retain the above copyright notice and this paragraph in its entirety, (2) 82949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * distributions including binary code include the above copyright notice and 92949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * this paragraph in its entirety in the documentation or other materials 102949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * provided with the distribution, and (3) all advertising materials mentioning 112949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * features or use of this software display the following acknowledgement: 122949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * ``This product includes software developed by the University of California, 132949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 142949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * the University nor the names of its contributors may be used to endorse 152949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * or promote products derived from this software without specific prior 162949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * written permission. 172949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 182949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 192949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 202949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project */ 212949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 222949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifndef lint 232949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Projectstatic const char rcsid[] _U_ = 2453f17a9db278d33517d9888dd77848f554522a38JP Abgrall "@(#) $Header: /tcpdump/master/tcpdump/setsignal.c,v 1.11 2003-11-16 09:36:42 guy Exp $ (LBL)"; 252949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 262949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 272949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifdef HAVE_CONFIG_H 282949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include "config.h" 292949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 302949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 312949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include <tcpdump-stdinc.h> 322949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 332949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include <signal.h> 342949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifdef HAVE_SIGACTION 352949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include <string.h> 362949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 372949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 382949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifdef HAVE_OS_PROTO_H 392949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include "os-proto.h" 402949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 412949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 422949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#include "setsignal.h" 432949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 442949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project/* 452949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * An OS-independent signal() with, whenever possible, partial BSD 462949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * semantics, i.e. the signal handler is restored following service 472949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * of the signal, but system calls are *not* restarted, so that if 482949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * "pcap_breakloop()" is called in a signal handler in a live capture, 492949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * the read/recvfrom/whatever in the live capture doesn't get restarted, 502949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * it returns -1 and sets "errno" to EINTR, so we can break out of the 512949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * live capture loop. 522949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * 532949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * We use "sigaction()" if available. We don't specify that the signal 542949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * should restart system calls, so that should always do what we want. 552949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * 562949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Otherwise, if "sigset()" is available, it probably has BSD semantics 572949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * while "signal()" has traditional semantics, so we use "sigset()"; it 582949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * might cause system calls to be restarted for the signal, however. 592949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * I don't know whether, in any systems where it did cause system calls to 602949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * be restarted, there was a way to ask it not to do so; there may no 612949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * longer be any interesting systems without "sigaction()", however, 622949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * and, if there are, they might have "sigvec()" with SV_INTERRUPT 632949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * (which I think first appeared in 4.3BSD). 642949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * 652949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Otherwise, we use "signal()" - which means we might get traditional 662949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * semantics, wherein system calls don't get restarted *but* the 672949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * signal handler is reset to SIG_DFL and the signal is not blocked, 682949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * so that a subsequent signal would kill the process immediately. 692949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * 702949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * Did I mention that signals suck? At least in POSIX-compliant systems 712949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project * they suck far less, as those systems have "sigaction()". 722949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project */ 732949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source ProjectRETSIGTYPE 742949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project(*setsignal (int sig, RETSIGTYPE (*func)(int)))(int) 752949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project{ 762949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifdef HAVE_SIGACTION 772949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project struct sigaction old, new; 782949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 792949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project memset(&new, 0, sizeof(new)); 802949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project new.sa_handler = func; 8153f17a9db278d33517d9888dd77848f554522a38JP Abgrall if (sig == SIGCHLD) 8253f17a9db278d33517d9888dd77848f554522a38JP Abgrall new.sa_flags = SA_RESTART; 832949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project if (sigaction(sig, &new, &old) < 0) 842949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project return (SIG_ERR); 852949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project return (old.sa_handler); 862949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 872949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#else 882949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#ifdef HAVE_SIGSET 892949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project return (sigset(sig, func)); 902949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#else 912949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project return (signal(sig, func)); 922949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 932949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project#endif 942949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project} 952949f58a438f6fd85f66a8b7ed4708042cde4b37The Android Open Source Project 96