xiosignal.c

   1 /* source: xiosignal.c */
   2 /* Copyright Gerhard Rieger 2001-2003 */
   3 /* Published under the GNU General Public License V.2, see file COPYING */
   4
   5 /* this file contains code for handling signals (except SIGCHLD) */
   6
   7 #include "config.h"
   8 #include "xioconfig.h"  /* what features are enabled */
   9
  10 #include "sysincludes.h"
  11
  12 #include "mytypes.h"
  13 #include "compat.h"
  14 #include "error.h"
  15
  16 #include "sycls.h"
  17
  18
  19 #define SOCAT_MAXPIDS 4
  20
  21 struct socat_sig_desc {
  22    int sig_use;
  23    pid_t  sig_pids[SOCAT_MAXPIDS];
  24 } ;
  25
  26 #if 0
  27 size_t socat_sigint_use;        /* how many pids are set in following array */
  28 static pid_t socat_sigint_pids[SOCAT_MAXPIDS];
  29 size_t socat_sigquit_use;       /* how many pids are set in following array */
  30 static pid_t socat_sigquit_pids[SOCAT_MAXPIDS];
  31 #else
  32 static struct socat_sig_desc socat_sighup;
  33 static struct socat_sig_desc socat_sigint;
  34 static struct socat_sig_desc socat_sigquit;
  35 #endif
  36
  37
  38 static struct socat_sig_desc *socat_get_sig_desc(int signum) {
  39    struct socat_sig_desc *sigdesc;
  40    switch (signum) {
  41    case SIGHUP:  sigdesc = &socat_sighup;  break;
  42    case SIGINT:  sigdesc = &socat_sigint;  break;
  43    case SIGQUIT: sigdesc = &socat_sigquit; break;
  44    default: sigdesc = NULL; break;
  45    }
  46    return sigdesc;
  47 }
  48
  49 /* a signal handler that eventually passes the signal to sub processes */
  50 void socatsignalpass(int sig) {
  51    int i;
  52    struct socat_sig_desc *sigdesc;
  53
  54    Debug1("socatsignalpass(%d)", sig);
  55    if ((sigdesc = socat_get_sig_desc(sig)) == NULL) {
  56       return;
  57    }
  58
  59    for (i=0; i<sigdesc->sig_use; ++i) {
  60       if (sigdesc->sig_pids[i]) {
  61          if (Kill(sigdesc->sig_pids[i], sig) < 0) {
  62             Warn3("kill("F_pid", %d): %s",
  63                   sigdesc->sig_pids[i], sig, strerror(errno));
  64          }
  65       }
  66    }
  67 #if !HAVE_SIGACTION
  68    Signal(sig, socatsignalpass);
  69 #endif /* !HAVE_SIGACTION */
  70    Debug("socatsignalpass() ->");
  71 }
  72
  73
  74 /* register the sub process pid for passing of signals of type signum.
  75    Only for SIGHUP, SIGINT, and SIGQUIT!
  76    returns 0 on success or <0 if an error occurred */
  77 int xio_opt_signal(pid_t pid, int signum) {
  78    struct socat_sig_desc *sigdesc;
  79
  80    if ((sigdesc = socat_get_sig_desc(signum)) == NULL) {
  81       Error("sub process registered for unsupported signal");
  82       return -1;
  83    }
  84
  85    if (sigdesc->sig_use >= SOCAT_MAXPIDS) {
  86       Error1("too many sub processes registered for signal %d", signum);
  87       return -1;
  88    }
  89    if (sigdesc->sig_use == 0) {
  90       /* the special signal handler has not been registered yet - do it now */
  91 #if HAVE_SIGACTION
  92       struct sigaction act;
  93       memset(&act, 0, sizeof(struct sigaction));
  94       act.sa_flags   = SA_RESTART;
  95       act.sa_handler = socatsignalpass;
  96       if (Sigaction(signum, &act, NULL) < 0) {
  97          /*! man does not say that errno is defined */
  98          Warn3("sigaction(%d, %p, NULL): %s", signum, &act, strerror(errno));
  99       }
 100 #else
 101       Signal(signum, socatsignalpass);
 102 #endif /* !HAVE_SIGACTION */
 103    }
 104    sigdesc->sig_pids[sigdesc->sig_use++] = pid;
 105    return 0;
 106 }
 107