tools/purge/signal.cc

   1 /*
   2  * Copyright (C) 1996-2023 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
  61 SigFunc*
  62 Signal( 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
 101 void
 102 sigChild( 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