ngircd-tor/src/ngircd/proc.c

165 lines
3.4 KiB
C

/*
* ngIRCd -- The Next Generation IRC Daemon
* Copyright (c)2001-2011 Alexander Barton (alex@barton.de) and Contributors.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* Please read the file COPYING, README and AUTHORS for more information.
*/
#include "portab.h"
/**
* @file
* Process management
*/
#include "imp.h"
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "log.h"
#include "io.h"
#include "conn.h"
#include "exp.h"
#include "sighandlers.h"
#include "proc.h"
/**
* Initialize process structure.
*/
GLOBAL void
Proc_InitStruct (PROC_STAT *proc)
{
assert(proc != NULL);
proc->pid = 0;
proc->pipe_fd = -1;
}
/**
* Fork a child process.
*/
GLOBAL pid_t
Proc_Fork(PROC_STAT *proc, int *pipefds, void (*cbfunc)(int, short), int timeout)
{
pid_t pid;
unsigned int seed;
assert(proc != NULL);
assert(pipefds != NULL);
assert(cbfunc != NULL);
if (pipe(pipefds) != 0) {
Log(LOG_ALERT, "Can't create output pipe for child process: %s!",
strerror(errno));
return -1;
}
seed = (unsigned int)rand();
pid = fork();
switch (pid) {
case -1:
/* Error on fork: */
Log(LOG_CRIT, "Can't fork child process: %s!", strerror(errno));
close(pipefds[0]);
close(pipefds[1]);
return -1;
case 0:
/* New child process: */
srand(seed ^ (unsigned int)time(NULL) ^ getpid());
Signals_Exit();
signal(SIGTERM, Proc_GenericSignalHandler);
signal(SIGALRM, Proc_GenericSignalHandler);
close(pipefds[0]);
alarm(timeout);
return 0;
}
/* Old parent process: */
close(pipefds[1]);
if (!io_setnonblock(pipefds[0])
|| !io_event_create(pipefds[0], IO_WANTREAD, cbfunc)) {
Log(LOG_CRIT, "Can't register callback for child process: %s!",
strerror(errno));
close(pipefds[0]);
return -1;
}
proc->pid = pid;
proc->pipe_fd = pipefds[0];
return pid;
}
/**
* Generic signal handler for forked child processes.
*/
GLOBAL void
Proc_GenericSignalHandler(int Signal)
{
switch(Signal) {
case SIGTERM:
#ifdef DEBUG
Log_Subprocess(LOG_DEBUG, "Child got TERM signal, exiting.");
#endif
exit(1);
case SIGALRM:
#ifdef DEBUG
Log_Subprocess(LOG_DEBUG, "Child got ALARM signal, exiting.");
#endif
exit(1);
}
}
/**
* Read bytes from a pipe of a forked child process.
* In addition, this function makes sure that the child process is ignored
* after all data has been read or a fatal error occurred.
*/
GLOBAL size_t
Proc_Read(PROC_STAT *proc, void *buffer, size_t buflen)
{
ssize_t bytes_read = 0;
assert(buffer != NULL);
assert(buflen > 0);
bytes_read = read(proc->pipe_fd, buffer, buflen);
if (bytes_read < 0) {
if (errno == EAGAIN)
return 0;
Log(LOG_CRIT, "Can't read from child process %ld: %s",
proc->pid, strerror(errno));
Proc_Close(proc);
bytes_read = 0;
} else if (bytes_read == 0) {
/* EOF: clean up */
LogDebug("Child process %ld: EOF reached, closing pipe.",
proc->pid);
Proc_Close(proc);
}
return (size_t)bytes_read;
}
/**
* Close pipe to a forked child process.
*/
GLOBAL void
Proc_Close(PROC_STAT *proc)
{
/* Close socket, if it exists */
if (proc->pipe_fd >= 0)
io_close(proc->pipe_fd);
Proc_InitStruct(proc);
}
/* -eof- */