| 1 | /*
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| 2 | Unix SMB/CIFS implementation.
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| 3 | signal handling functions
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| 4 |
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| 5 | Copyright (C) Andrew Tridgell 1998
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| 6 |
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| 7 | This program is free software; you can redistribute it and/or modify
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| 8 | it under the terms of the GNU General Public License as published by
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| 9 | the Free Software Foundation; either version 2 of the License, or
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| 10 | (at your option) any later version.
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| 11 |
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| 12 | This program is distributed in the hope that it will be useful,
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | GNU General Public License for more details.
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| 16 |
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| 17 | You should have received a copy of the GNU General Public License
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| 18 | along with this program; if not, write to the Free Software
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| 19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 20 | */
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| 21 |
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| 22 | #include "includes.h"
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| 23 |
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| 24 | /****************************************************************************
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| 25 | Catch child exits and reap the child zombie status.
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| 26 | ****************************************************************************/
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| 27 |
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| 28 | static void sig_cld(int signum)
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| 29 | {
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| 30 | while (sys_waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0)
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| 31 | ;
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| 32 |
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| 33 | /*
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| 34 | * Turns out it's *really* important not to
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| 35 | * restore the signal handler here if we have real POSIX
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| 36 | * signal handling. If we do, then we get the signal re-delivered
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| 37 | * immediately - hey presto - instant loop ! JRA.
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| 38 | */
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| 39 |
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| 40 | #if !defined(HAVE_SIGACTION)
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| 41 | CatchSignal(SIGCLD, sig_cld);
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| 42 | #endif
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| 43 | }
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| 44 |
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| 45 | /****************************************************************************
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| 46 | catch child exits - leave status;
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| 47 | ****************************************************************************/
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| 48 |
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| 49 | static void sig_cld_leave_status(int signum)
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| 50 | {
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| 51 | /*
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| 52 | * Turns out it's *really* important not to
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| 53 | * restore the signal handler here if we have real POSIX
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| 54 | * signal handling. If we do, then we get the signal re-delivered
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| 55 | * immediately - hey presto - instant loop ! JRA.
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| 56 | */
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| 57 |
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| 58 | #if !defined(HAVE_SIGACTION)
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| 59 | CatchSignal(SIGCLD, sig_cld_leave_status);
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| 60 | #endif
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| 61 | }
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| 62 |
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| 63 | /*******************************************************************
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| 64 | Block sigs.
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| 65 | ********************************************************************/
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| 66 |
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| 67 | void BlockSignals(BOOL block,int signum)
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| 68 | {
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| 69 | #ifdef HAVE_SIGPROCMASK
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| 70 | sigset_t set;
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| 71 | sigemptyset(&set);
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| 72 | sigaddset(&set,signum);
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| 73 | sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL);
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| 74 | #elif defined(HAVE_SIGBLOCK)
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| 75 | if (block) {
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| 76 | sigblock(sigmask(signum));
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| 77 | } else {
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| 78 | sigsetmask(siggetmask() & ~sigmask(signum));
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| 79 | }
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| 80 | #else
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| 81 | /* yikes! This platform can't block signals? */
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| 82 | static int done;
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| 83 | if (!done) {
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| 84 | DEBUG(0,("WARNING: No signal blocking available\n"));
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| 85 | done=1;
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| 86 | }
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| 87 | #endif
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| 88 | }
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| 89 |
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| 90 | /*******************************************************************
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| 91 | Catch a signal. This should implement the following semantics:
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| 92 |
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| 93 | 1) The handler remains installed after being called.
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| 94 | 2) The signal should be blocked during handler execution.
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| 95 | ********************************************************************/
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| 96 |
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| 97 | void (*CatchSignal(int signum,void (*handler)(int )))(int)
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| 98 | {
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| 99 | #ifdef HAVE_SIGACTION
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| 100 | struct sigaction act;
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| 101 | struct sigaction oldact;
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| 102 |
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| 103 | ZERO_STRUCT(act);
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| 104 |
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| 105 | act.sa_handler = handler;
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| 106 | #ifdef SA_RESTART
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| 107 | /*
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| 108 | * We *want* SIGALRM to interrupt a system call.
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| 109 | */
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| 110 | if(signum != SIGALRM)
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| 111 | act.sa_flags = SA_RESTART;
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| 112 | #endif
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| 113 | sigemptyset(&act.sa_mask);
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| 114 | sigaddset(&act.sa_mask,signum);
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| 115 | sigaction(signum,&act,&oldact);
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| 116 | return oldact.sa_handler;
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| 117 | #else /* !HAVE_SIGACTION */
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| 118 | /* FIXME: need to handle sigvec and systems with broken signal() */
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| 119 | return signal(signum, handler);
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| 120 | #endif
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| 121 | }
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| 122 |
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| 123 | /*******************************************************************
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| 124 | Ignore SIGCLD via whatever means is necessary for this OS.
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| 125 | ********************************************************************/
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| 126 |
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| 127 | void CatchChild(void)
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| 128 | {
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| 129 | CatchSignal(SIGCLD, sig_cld);
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| 130 | }
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| 131 |
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| 132 | /*******************************************************************
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| 133 | Catch SIGCLD but leave the child around so it's status can be reaped.
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| 134 | ********************************************************************/
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| 135 |
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| 136 | void CatchChildLeaveStatus(void)
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| 137 | {
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| 138 | CatchSignal(SIGCLD, sig_cld_leave_status);
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| 139 | }
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