d72b24a2fe
Handle EAGAIN and EWOULDBLOCK more gracefully when dealing with safe_read(). All occurrences of safe_read() should only be invoked on fds that have signaled ready-to-read state via the epoll() mechanism, so this change should not result in any observable difference, but it is best to be safe. Additionally, a constant stack variable is converted to an equivalent macro define for cleanliness. Finally, print the error type encountered if reading data from an ARP response fails with a read error.
95 lines
2.7 KiB
C
95 lines
2.7 KiB
C
/* sys.c - linux-specific signal and epoll functions
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* Time-stamp: <2011-03-30 23:40:33 nk>
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*
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* (c) 2010-2011 Nicholas J. Kain <njkain at gmail dot com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <signal.h>
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#include <sys/epoll.h>
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#include <sys/signalfd.h>
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#include "config.h"
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#include "log.h"
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#include "pidfile.h"
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#include "sys.h"
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char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT;
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void setup_signals(struct client_state_t *cs)
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{
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sigset_t mask;
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sigemptyset(&mask);
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sigaddset(&mask, SIGUSR1);
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sigaddset(&mask, SIGUSR2);
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sigaddset(&mask, SIGTERM);
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if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
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suicide("sigprocmask failed");
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if (cs->signalFd >= 0) {
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epoll_del(cs, cs->signalFd);
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close(cs->signalFd);
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}
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cs->signalFd = signalfd(-1, &mask, SFD_NONBLOCK);
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if (cs->signalFd < 0)
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suicide("signalfd failed");
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epoll_add(cs, cs->signalFd);
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}
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// @cs can be NULL
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void background(struct client_state_t *cs)
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{
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static char called;
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if (!called) {
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called = 1; /* Do not fork again. */
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if (daemon(0, 0) == -1) {
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perror("fork");
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exit(EXIT_SUCCESS);
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}
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if (cs)
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setup_signals(cs);
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}
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if (file_exists(pidfile, "w") == -1) {
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log_line("cannot open pidfile for write!");
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} else
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write_pid(pidfile);
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}
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void epoll_add(struct client_state_t *cs, int fd)
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{
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struct epoll_event ev;
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int r;
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ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP;
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ev.data.fd = fd;
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r = epoll_ctl(cs->epollFd, EPOLL_CTL_ADD, fd, &ev);
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if (r == -1)
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suicide("epoll_add failed %s", strerror(errno));
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}
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void epoll_del(struct client_state_t *cs, int fd)
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{
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struct epoll_event ev;
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int r;
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ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP;
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ev.data.fd = fd;
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r = epoll_ctl(cs->epollFd, EPOLL_CTL_DEL, fd, &ev);
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if (r == -1)
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suicide("epoll_del failed %s", strerror(errno));
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}
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