signal.cc
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1/*
2 * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
3 *
4 * Squid software is distributed under GPLv2+ license and includes
5 * contributions from numerous individuals and organizations.
6 * Please see the COPYING and CONTRIBUTORS files for details.
7 */
8
9// Author: Jens-S. V?ckler <voeckler@rvs.uni-hannover.de>
10// File: signal.cc
11// Date: Sat Feb 28 1998
12// Compiler: gcc 2.7.2.x series
13//
14// Books: W. Richard Steven, "Advanced Programming in the UNIX Environment",
15// Addison-Wesley, 1992.
16//
17// (c) 1998 Lehrgebiet Rechnernetze und Verteilte Systeme
18// Universit?t Hannover, Germany
19//
20// Permission to use, copy, modify, distribute, and sell this software
21// and its documentation for any purpose is hereby granted without fee,
22// provided that (i) the above copyright notices and this permission
23// notice appear in all copies of the software and related documentation,
24// and (ii) the names of the Lehrgebiet Rechnernetze und Verteilte
25// Systeme and the University of Hannover may not be used in any
26// advertising or publicity relating to the software without the
27// specific, prior written permission of Lehrgebiet Rechnernetze und
28// Verteilte Systeme and the University of Hannover.
29//
30// THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
31// EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
32// WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
33//
34// IN NO EVENT SHALL THE LEHRGEBIET RECHNERNETZE UND VERTEILTE SYSTEME OR
35// THE UNIVERSITY OF HANNOVER BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
36// INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES
37// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT
38// ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY,
39// ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
40// SOFTWARE.
41//
42// Revision 1.3 1999/01/19 13:11:52 cached
43// adaptations necessary for AIX.
44//
45// Revision 1.2 1999/01/19 11:00:50 voeckler
46// added psignal(int,const char*) compatibility function.
47//
48// Revision 1.1 1998/08/13 21:51:58 voeckler
49// Initial revision
50//
51
52#include "squid.h"
53#include "signal.hh"
54
55#include <cerrno>
56#include <cstring>
57#include <memory.h>
58#include <unistd.h>
59#include <sys/wait.h>
60
61SigFunc*
62Signal( int signo, SigFunc* newhandler, bool doInterrupt )
63// purpose: install reliable signals
64// paramtr: signo (IN): signal for which a handler is to be installed
65// newhandler (IN): function pointer to the signal handler
66// doInterrupt (IN): interrupted system calls wanted!
67// returns: the old signal handler, or SIG_ERR in case of error.
68{
69 struct sigaction action, old;
70
71 memset( &old, 0, sizeof(old) );
72 memset( &action, 0, sizeof(action) );
73
74 // action.sa_handler = newhandler; I HATE TYPE-OVERCORRECTNESS !
75 memmove( &action.sa_handler, &newhandler, sizeof(SigFunc*) );
76 sigemptyset( &action.sa_mask );
77
78 if ( signo == SIGCHLD ) {
79 action.sa_flags |= SA_NOCLDSTOP;
80
81#ifdef SA_NODEFER
82 action.sa_flags |= SA_NODEFER; // SYSV: don't block current signal
83#endif
84 }
85
86 if ( signo == SIGALRM || doInterrupt ) {
87#ifdef SA_INTERRUPT
88 action.sa_flags |= SA_INTERRUPT; // SunOS, obsoleted by POSIX
89#endif
90 } else {
91#ifdef SA_RESTART
92 action.sa_flags |= SA_RESTART; // BSD, SVR4
93#endif
94 }
95
96 return ( sigaction( signo, &action, &old ) < 0 ) ?
97 (SigFunc*) SIG_ERR :
98 (SigFunc*) old.sa_handler;
99}
100
101void
102sigChild( int signo )
103// purpose: supply ad hoc child handler with output on stderr
104// paramtr: signo (IN): == SIGCHLD
105// returns: only if OS uses a return type for signal handler
106// seealso: Stevens, UNP, figure 5.11 *and* Stevens, APUE, figure 8.3
107{
108 pid_t pid;
109 int status = signo; // to stop GNU from complaining...
110
111 int saveerr = errno;
112 while ( (pid = waitpid( -1, &status, WNOHANG )) > 0 ) {
113 if ( WIFEXITED(status) ) {
114 fprintf( stderr, "child (pid=%ld) reaped, status %d\n%c",
115 (long) pid, WEXITSTATUS(status), 0 );
116 } else if ( WIFSIGNALED(status) ) {
117 fprintf( stderr, "child (pid=%ld) died on signal %d%s\n%c",
118 (long) pid, WTERMSIG(status),
119#ifdef WCOREDUMP
120 WCOREDUMP(status) ? " (core generated)" : "",
121#else
122 "",
123#endif
124 0 );
125 } else {
126 fprintf( stderr, "detected dead child (pid=%ld), status %d\n%c",
127 (long) pid, status, 0 );
128 }
129 }
130 errno = saveerr;
131}
132
static pid_t pid
Definition: IcmpSquid.cc:34
#define SA_RESTART
#define SA_NODEFER
static bool action(int fd, size_t metasize, const char *fn, const char *url, const SquidMetaList &meta)
Definition: purge.cc:311
SigFunc * Signal(int signo, SigFunc *newhandler, bool doInterrupt)
Definition: signal.cc:62
void sigChild(int signo)
Definition: signal.cc:102

 

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