| 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 3 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, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 |
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| 21 | #include "includes.h"
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| 22 |
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| 23 | /****************************************************************************
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| 24 | Catch child exits and reap the child zombie status.
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| 25 | ****************************************************************************/
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| 26 |
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| 27 | static void sig_cld(int signum)
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| 28 | {
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| 29 | while (sys_waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0)
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| 30 | ;
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| 31 |
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| 32 | /*
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| 33 | * Turns out it's *really* important not to
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| 34 | * restore the signal handler here if we have real POSIX
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| 35 | * signal handling. If we do, then we get the signal re-delivered
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| 36 | * immediately - hey presto - instant loop ! JRA.
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| 37 | */
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| 38 |
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| 39 | #if !defined(HAVE_SIGACTION)
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| 40 | CatchSignal(SIGCLD, sig_cld);
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| 41 | #endif
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| 42 | }
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| 43 |
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| 44 | /****************************************************************************
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| 45 | catch child exits - leave status;
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| 46 | ****************************************************************************/
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| 47 |
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| 48 | static void sig_cld_leave_status(int signum)
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| 49 | {
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| 50 | /*
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| 51 | * Turns out it's *really* important not to
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| 52 | * restore the signal handler here if we have real POSIX
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| 53 | * signal handling. If we do, then we get the signal re-delivered
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| 54 | * immediately - hey presto - instant loop ! JRA.
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| 55 | */
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| 56 |
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| 57 | #if !defined(HAVE_SIGACTION)
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| 58 | CatchSignal(SIGCLD, sig_cld_leave_status);
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| 59 | #endif
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| 60 | }
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| 61 |
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| 62 | /*******************************************************************
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| 63 | Block sigs.
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| 64 | ********************************************************************/
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| 65 |
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| 66 | void BlockSignals(bool block,int signum)
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| 67 | {
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| 68 | #ifdef HAVE_SIGPROCMASK
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| 69 | sigset_t set;
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| 70 | sigemptyset(&set);
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| 71 | sigaddset(&set,signum);
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| 72 | sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL);
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| 73 | #elif defined(HAVE_SIGBLOCK)
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| 74 | if (block) {
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| 75 | sigblock(sigmask(signum));
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| 76 | } else {
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| 77 | sigsetmask(siggetmask() & ~sigmask(signum));
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| 78 | }
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| 79 | #else
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| 80 | /* yikes! This platform can't block signals? */
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| 81 | static int done;
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| 82 | if (!done) {
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| 83 | DEBUG(0,("WARNING: No signal blocking available\n"));
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| 84 | done=1;
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| 85 | }
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| 86 | #endif
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| 87 | }
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| 88 |
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| 89 | /*******************************************************************
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| 90 | Catch a signal. This should implement the following semantics:
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| 91 |
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| 92 | 1) The handler remains installed after being called.
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| 93 | 2) The signal should be blocked during handler execution.
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| 94 | ********************************************************************/
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| 95 |
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| 96 | void (*CatchSignal(int signum,void (*handler)(int )))(int)
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| 97 | {
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| 98 | #ifdef HAVE_SIGACTION
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| 99 | struct sigaction act;
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| 100 | struct sigaction oldact;
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| 101 |
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| 102 | ZERO_STRUCT(act);
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| 103 |
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| 104 | act.sa_handler = handler;
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| 105 | #ifdef SA_RESTART
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| 106 | /*
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| 107 | * We *want* SIGALRM to interrupt a system call.
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| 108 | */
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| 109 | if(signum != SIGALRM)
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| 110 | act.sa_flags = SA_RESTART;
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| 111 | #endif
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| 112 | sigemptyset(&act.sa_mask);
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| 113 | sigaddset(&act.sa_mask,signum);
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| 114 | sigaction(signum,&act,&oldact);
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| 115 | return oldact.sa_handler;
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| 116 | #else /* !HAVE_SIGACTION */
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| 117 | /* FIXME: need to handle sigvec and systems with broken signal() */
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| 118 | return signal(signum, handler);
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| 119 | #endif
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| 120 | }
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| 121 |
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| 122 | /*******************************************************************
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| 123 | Ignore SIGCLD via whatever means is necessary for this OS.
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| 124 | ********************************************************************/
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| 125 |
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| 126 | void CatchChild(void)
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| 127 | {
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| 128 | CatchSignal(SIGCLD, sig_cld);
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| 129 | }
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| 130 |
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| 131 | /*******************************************************************
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| 132 | Catch SIGCLD but leave the child around so it's status can be reaped.
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| 133 | ********************************************************************/
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| 134 |
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| 135 | void CatchChildLeaveStatus(void)
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| 136 | {
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| 137 | CatchSignal(SIGCLD, sig_cld_leave_status);
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| 138 | }
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