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/* $Id: xiosigchld.c,v 1.18 2005/03/13 12:20:43 gerhard Exp $ */
/* Copyright Gerhard Rieger 2001-2005 */
/* Published under the GNU General Public License V.2, see file COPYING */
/* this is the source of the extended child signal handler */
#include "xiosysincludes.h"
#include "xioopen.h"
/*!! with socat, at most 4 exec children exist */
pid_t diedunknown1; /* child died before it is registered */
pid_t diedunknown2;
pid_t diedunknown3;
pid_t diedunknown4;
int xiosetsigchild(xiofile_t *xfd, int (*callback)(struct single *)) {
if (xfd->tag != XIO_TAG_DUAL) {
xfd->stream.sigchild = callback;
} else {
xfd->dual.stream[0]->stream.sigchild = callback;
xfd->dual.stream[1]->stream.sigchild = callback;
}
return 0;
}
/* exec'd child has died, perform appropriate changes to descriptor */
static int sigchld_stream(struct single *file) {
/*!! call back to application */
file->para.exec.pid = 0;
if (file->sigchild) {
return (*file->sigchild)(file);
}
return 0;
}
/* return 0 if socket is not responsible for deadchild */
static int xio_checkchild(xiofile_t *socket, int socknum, pid_t deadchild) {
int retval;
if (socket != NULL) {
if (socket->tag != XIO_TAG_DUAL) {
if ((socket->stream.howtoend == END_KILL ||
socket->stream.howtoend == END_CLOSE_KILL ||
socket->stream.howtoend == END_SHUTDOWN_KILL) &&
socket->stream.para.exec.pid == deadchild) {
Info2("exec'd process %d on socket %d terminated",
socket->stream.para.exec.pid, socknum);
sigchld_stream(&socket->stream);
return 1;
}
} else {
if (retval = xio_checkchild(socket->dual.stream[0], socknum, deadchild))
return retval;
else
return xio_checkchild(socket->dual.stream[1], socknum, deadchild);
}
}
return 0;
}
/* this is the signal handler for SIGCHLD */
/* the current socat/xio implementation knows two kinds of children:
exec/system addresses perform a fork: these children are registered and
there death influences the parents flow;
listen-socket with fork children: these children are "anonymous" and their
death does not effect the parent process (now; maybe we have a child
process counter later) */
void childdied(int signum) {
pid_t pid;
int _errno;
int status;
bool wassig = false;
int i;
_errno = errno; /* save current value; e.g., select() on Cygwin seems
to set it to EINTR _before_ handling the signal, and
then passes the value left by the signal handler to
the caller of select(), accept() etc. */
Info1("childdied(signum=%d)", signum);
do {
pid = Waitpid(-1, &status, WNOHANG);
if (pid == 0 || (pid < 0 && errno == ECHILD)) {
if (!wassig) {
Warn("waitpid(-1, {}, WNOHANG): no child process");
}
Info("childdied() finished");
errno = _errno;
return;
}
wassig = true;
if (pid < 0) {
Warn2("waitpid(-1, {%d}, WNOHANG): %s", status, strerror(errno));
Info("childdied() finished");
errno = _errno;
return;
}
/*! indent */
i = 0;
while (i < XIO_MAXSOCK) {
if (xio_checkchild(sock[i], i, pid)) break;
++i;
}
if (i == XIO_MAXSOCK) {
Info2("childdied(%d): cannot identify child %d", signum, pid);
if (diedunknown1 == 0) {
diedunknown1 = pid;
Debug("saving pid in diedunknown1");
} else if (diedunknown2 == 0) {
diedunknown2 = pid;
Debug("saving pid in diedunknown2");
} else if (diedunknown3 == 0) {
diedunknown3 = pid;
Debug("saving pid in diedunknown3");
} else {
diedunknown4 = pid;
Debug("saving pid in diedunknown4");
}
}
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == 0) {
Info2("waitpid(): child %d exited with status %d",
pid, WEXITSTATUS(status));
} else {
Warn2("waitpid(): child %d exited with status %d",
pid, WEXITSTATUS(status));
}
} else if (WIFSIGNALED(status)) {
Info2("waitpid(): child %d exited on signal %d",
pid, WTERMSIG(status));
} else if (WIFSTOPPED(status)) {
Info2("waitpid(): child %d stopped on signal %d",
pid, WSTOPSIG(status));
} else {
Warn1("waitpid(): cannot determine status of child %d", pid);
}
#if !HAVE_SIGACTION
if (Signal(SIGCHLD, childdied) == SIG_ERR) {
Warn2("signal(SIGCHLD, %p): %s", childdied, strerror(errno));
}
#endif /* !HAVE_SIGACTION */
} while (1);
Info("childdied() finished");
errno = _errno;
}
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