tools/purge/signal.cc

   1 //
   2 // $Id$
   3 //
   4 // Author:   Jens-S. V?ckler <voeckler@rvs.uni-hannover.de>
   5 // File:     signal.cc
   6 // Date:     Sat Feb 28 1998
   7 // Compiler: gcc 2.7.2.x series
   8 //
   9 // Books:    W. Richard Steven, "Advanced Programming in the UNIX Environment",
  10 //           Addison-Wesley, 1992.
  11 //
  12 // (c) 1998 Lehrgebiet Rechnernetze und Verteilte Systeme
  13 //          Universit?t Hannover, Germany
  14 //
  15 // Permission to use, copy, modify, distribute, and sell this software
  16 // and its documentation for any purpose is hereby granted without fee,
  17 // provided that (i) the above copyright notices and this permission
  18 // notice appear in all copies of the software and related documentation,
  19 // and (ii) the names of the Lehrgebiet Rechnernetze und Verteilte
  20 // Systeme and the University of Hannover may not be used in any
  21 // advertising or publicity relating to the software without the
  22 // specific, prior written permission of Lehrgebiet Rechnernetze und
  23 // Verteilte Systeme and the University of Hannover.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  27 // WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  28 //
  29 // IN NO EVENT SHALL THE LEHRGEBIET RECHNERNETZE UND VERTEILTE SYSTEME OR
  30 // THE UNIVERSITY OF HANNOVER BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
  31 // INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES
  32 // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT
  33 // ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY,
  34 // ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  35 // SOFTWARE.
  36 //
  37 // Revision 1.3  1999/01/19 13:11:52  cached
  38 // adaptations necessary for AIX.
  39 //
  40 // Revision 1.2  1999/01/19 11:00:50  voeckler
  41 // added psignal(int,const char*) compatibility function.
  42 //
  43 // Revision 1.1  1998/08/13 21:51:58  voeckler
  44 // Initial revision
  45 //
  46 //
  47
  48 #if defined(__GNUC__) || defined(__GNUG__)
  49 #pragma implementation
  50 #endif
  51
  52 #include "config.h"
  53 #include "signal.hh"
  54
  55 //#include <sys/types.h>
  56 #include <errno.h>
  57 #include <string.h>
  58 #include <memory.h>
  59 #include <stdio.h>
  60 #include <unistd.h>
  61 #include <sys/wait.h>
  62 //#include <signal.h>
  63
  64 SigFunc*
  65 Signal( int signo, SigFunc* newhandler, bool doInterrupt )
  66 // purpose: install reliable signals
  67 // paramtr: signo (IN): signal for which a handler is to be installed
  68 //          newhandler (IN): function pointer to the signal handler
  69 //          doInterrupt (IN): interrupted system calls wanted!
  70 // returns: the old signal handler, or SIG_ERR in case of error.
  71 {
  72     struct sigaction action, old;
  73
  74     memset( &old, 0, sizeof(old) );
  75     memset( &action, 0, sizeof(action) );
  76
  77     // action.sa_handler = newhandler; I HATE TYPE-OVERCORRECTNESS !
  78     memmove( &action.sa_handler, &newhandler, sizeof(SigFunc*) );
  79     sigemptyset( &action.sa_mask );
  80
  81     if ( signo == SIGCHLD ) {
  82         action.sa_flags |= SA_NOCLDSTOP;
  83
  84 #ifdef SA_NODEFER
  85         action.sa_flags |= SA_NODEFER;   // SYSV: don't block current signal
  86 #endif
  87     }
  88
  89     if ( signo == SIGALRM || doInterrupt ) {
  90 #ifdef SA_INTERRUPT
  91         action.sa_flags |= SA_INTERRUPT; // SunOS, obsoleted by POSIX
  92 #endif
  93     } else {
  94 #ifdef SA_RESTART
  95         action.sa_flags |= SA_RESTART;   // BSD, SVR4
  96 #endif
  97     }
  98
  99     return ( sigaction( signo, &action, &old ) < 0 ) ?
 100            (SigFunc*) SIG_ERR :
 101            (SigFunc*) old.sa_handler;
 102 }
 103
 104 SIGRETTYPE
 105 sigChild( int signo )
 106 // purpose: supply ad hoc child handler with output on stderr
 107 // paramtr: signo (IN): == SIGCHLD
 108 // returns: only if OS uses a return type for signal handler
 109 // seealso: Stevens, UNP, figure 5.11 *and* Stevens, APUE, figure 8.3
 110 {
 111     pid_t pid;
 112     int  status = signo; // to stop GNU from complaining...
 113     char line[128];
 114
 115     int saveerr = errno;
 116     while ( (pid = waitpid( -1, &status, WNOHANG )) > 0 ) {
 117         if ( WIFEXITED(status) ) {
 118             snprintf( line, 128, "child (pid=%ld) reaped, status %d\n%c",
 119                      (long) pid, WEXITSTATUS(status), 0 );
 120         } else if ( WIFSIGNALED(status) ) {
 121             snprintf( line, 128, "child (pid=%ld) died on signal %d%s\n%c",
 122                      (long) pid, WTERMSIG(status),
 123 #ifdef WCOREDUMP
 124                      WCOREDUMP(status) ? " (core generated)" : "",
 125 #else
 126                      "",
 127 #endif
 128                      0 );
 129         } else {
 130             snprintf( line, 128, "detected dead child (pid=%ld), status %d\n%c",
 131                      (long) pid, status, 0 );
 132         }
 133         write( STDERR_FILENO, line, strlen(line) );
 134     }
 135     errno = saveerr;
 136
 137 #if SIGRETTYPE != void
 138     return 0;
 139 #endif
 140 }