Use epoll() and signalfd() in ifchd.
This commit is contained in:
Nicholas J. Kain
parent
fb56a9cb2b
commit
f2b4527179
@ -1,3 +0,0 @@
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write documentation...
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support BSD
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251
ifchd/ifchd.c
251
ifchd/ifchd.c
@ -1,5 +1,5 @@
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/* ifchd.c - interface change daemon
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* Time-stamp: <2010-11-13 08:07:54 njk>
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* Time-stamp: <2010-12-01 12:19:39 njk>
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*
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* (C) 2004-2010 Nicholas J. Kain <njkain at gmail dot com>
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*
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@ -26,6 +26,8 @@
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#include <sys/un.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/epoll.h>
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#include <sys/signalfd.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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@ -71,7 +73,9 @@ enum states {
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STATE_WINS
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};
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static volatile sig_atomic_t pending_exit;
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static int epollfd, signalFd;
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/* Extra two event slots are for signalFd and the listen socket. */
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static struct epoll_event events[SOCK_QUEUE+2];
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/* Socket fd, current state, and idle time for connections. */
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static int sks[SOCK_QUEUE], state[SOCK_QUEUE], idle_time[SOCK_QUEUE];
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@ -102,23 +106,6 @@ static pid_t peer_pid;
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static strlist_t *namesvrs[SOCK_QUEUE];
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static strlist_t *domains[SOCK_QUEUE];
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static void sighandler(int sig) {
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pending_exit = 1;
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}
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static void fix_signals(void) {
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disable_signal(SIGPIPE);
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disable_signal(SIGUSR1);
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disable_signal(SIGUSR2);
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disable_signal(SIGTSTP);
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disable_signal(SIGTTIN);
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disable_signal(SIGCHLD);
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disable_signal(SIGHUP);
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hook_signal(SIGINT, sighandler, 0);
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hook_signal(SIGTERM, sighandler, 0);
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}
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static void die_nulstr(strlist_t *p)
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{
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if (!p)
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@ -133,6 +120,29 @@ static void writeordie(int fd, const char *buf, int len)
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suicide("write returned error");
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}
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static void epoll_add(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(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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static void epoll_del(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(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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/* Abstracts away the details of accept()ing a socket connection. */
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/* Writes out each element in a strlist as an argument to a keyword in
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* a file. */
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static void write_resolve_list(const char *keyword, strlist_t *list)
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@ -300,6 +310,7 @@ static void add_sk(int sk)
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for (i = 0; i < SOCK_QUEUE; i++)
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if (sks[i] == -1) {
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new_sk(i, sk);
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epoll_add(sk);
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return;
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}
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}
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@ -315,6 +326,7 @@ static void close_idle_sk(void)
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if (sks[i] == -1)
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continue;
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if (time(NULL) - idle_time[i] > CONN_TIMEOUT) {
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epoll_del(sks[i]);
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close(sks[i]);
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new_sk(i, -1);
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}
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@ -532,7 +544,6 @@ static int get_listen(void)
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return lsock;
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}
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/* Abstracts away the details of accept()ing a socket connection. */
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static void accept_conns(int *lsock)
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{
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int ret;
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@ -567,8 +578,12 @@ static void accept_conns(int *lsock)
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case ENOTSOCK:
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case EINVAL:
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log_line("warning: accept returned %s!\n", strerror(errno));
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epoll_del(*lsock);
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close(*lsock);
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*lsock = get_listen();
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epoll_add(*lsock);
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return;
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case ECONNABORTED:
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@ -585,110 +600,138 @@ static void accept_conns(int *lsock)
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}
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}
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/* Core function that handles connections, gathers input, and calls
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* the state machine to do actual work. */
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static void dispatch_work(void)
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static void setup_signals()
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{
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sigset_t mask;
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sigemptyset(&mask);
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sigaddset(&mask, SIGPIPE);
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sigaddset(&mask, SIGUSR1);
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sigaddset(&mask, SIGUSR2);
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sigaddset(&mask, SIGTSTP);
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sigaddset(&mask, SIGTTIN);
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sigaddset(&mask, SIGCHLD);
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sigaddset(&mask, SIGHUP);
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sigaddset(&mask, SIGINT);
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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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signalFd = signalfd(-1, &mask, SFD_NONBLOCK);
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if (signalFd < 0)
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suicide("signalfd failed");
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}
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static void signal_dispatch()
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{
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int t, off = 0;
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struct signalfd_siginfo si;
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again:
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t = read(signalFd, (char *)&si + off, sizeof si - off);
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if (t < sizeof si - off) {
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if (t < 0) {
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if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR)
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goto again;
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else
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suicide("signalfd read error");
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}
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off += t;
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}
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switch (si.ssi_signo) {
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case SIGINT:
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case SIGTERM:
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exit(EXIT_SUCCESS);
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default:
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break;
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}
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}
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static void process_client_fd(int fd)
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{
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int lsock, ret, highfd, i, index;
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fd_set rfds;
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char buf[MAX_BUF];
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/* Initialize all structures to blank state. */
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for (i=0; i<SOCK_QUEUE; i++)
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sks[i] = -1;
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initialize_if_data();
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lsock = get_listen();
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for (;;) {
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FD_ZERO(&rfds);
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FD_SET(lsock, &rfds);
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/* find highest fd */
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for (i=0, highfd=0; i<SOCK_QUEUE; i++) {
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if (sks[i] != -1) {
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FD_SET(sks[i], &rfds);
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if (sks[i] > highfd)
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highfd = sks[i];
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}
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}
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if (lsock > highfd)
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highfd = lsock;
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ret = select(highfd + 1, &rfds, NULL, NULL, NULL);
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switch (ret) {
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case 0:
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close_idle_sk();
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break;
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case -1:
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if (pending_exit == 1)
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return;
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suicide("dispatch_work - select returned an error!");
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int r, index, sqidx = -1;
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for (int j = 0; j < SOCK_QUEUE; ++j) {
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if (sks[j] == fd) {
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sqidx = j;
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break;
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}
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if (pending_exit == 1)
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return;
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/* handle pending connections */
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if (FD_ISSET(lsock, &rfds))
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accept_conns(&lsock);
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/* Read in and process data on waiting connections */
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for (i=0; i<SOCK_QUEUE; i++) {
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if (sks[i] == -1)
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continue;
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if (!FD_ISSET(sks[i], &rfds))
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continue;
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idle_time[i] = time(NULL);
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memset(buf, '\0', sizeof(buf));
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read_again:
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ret = (int) read(sks[i], buf, MAX_BUF / 2 - 1);
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/* Check to see if peer closed socket */
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if (ret == 0) {
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close(sks[i]);
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new_sk(i, -1);
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continue;
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}
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if (sqidx == -1)
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suicide("epoll returned pending read for untracked fd");
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if (ret == -1) {
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if (errno == EINTR)
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goto read_again;
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log_line("dispatch_work: read returned %s.\n", strerror(errno));
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close(sks[i]);
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new_sk(i, -1);
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continue;
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idle_time[sqidx] = time(NULL);
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memset(buf, '\0', sizeof buf);
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r = safe_read(sks[sqidx], buf, sizeof buf / 2 - 1);
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if (r <= 0) {
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if (r != 0)
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log_line("error reading from client fd: %s", strerror(errno));
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goto fail;
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}
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/* Discard everything and close connection if we risk overflow.
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* This approach is maximally conservative... worst case is that
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* some client requests will get dropped. */
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index = strlen(ibuf[i]);
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if (index + strlen(buf) > MAX_BUF - 2) {
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close(sks[i]);
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new_sk(i, -1);
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continue;
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}
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index = strlen(ibuf[sqidx]);
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if (index + strlen(buf) > sizeof buf - 2)
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goto fail;
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/* Append new stream input avoiding overflow. */
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strlcpy(ibuf[i] + index, buf, sizeof(ibuf[i]) - index);
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strlcpy(ibuf[sqidx] + index, buf, sizeof ibuf[sqidx] - index);
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/* Decompose ibuf contents onto strlist. */
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index = stream_onto_list(i);
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index = stream_onto_list(sqidx);
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/* Remove everything that we've parsed into the list. */
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strlcpy(buf, ibuf[i] + index, sizeof(buf));
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strlcpy(ibuf[i], buf, sizeof(ibuf[i]));
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strlcpy(buf, ibuf[sqidx] + index, sizeof buf);
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strlcpy(ibuf[sqidx], buf, sizeof ibuf[sqidx]);
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/* Now we have a strlist of commands and arguments.
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* Decompose and execute it. */
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if (!head[i])
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if (!head[sqidx])
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return;
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curl[sqidx] = head[sqidx];
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execute_list(sqidx);
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return;
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fail:
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epoll_del(sks[sqidx]);
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close(sks[sqidx]);
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new_sk(sqidx, -1);
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}
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/* Core function that handles connections, gathers input, and calls
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* the state machine to do actual work. */
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static void dispatch_work(void)
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{
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int lsock;
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/* Initialize all structures to blank state. */
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for (int i = 0; i < SOCK_QUEUE; i++)
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sks[i] = -1;
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initialize_if_data();
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lsock = get_listen();
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epollfd = epoll_create1(0);
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if (epollfd == -1)
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suicide("epoll_create1 failed");
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epoll_add(lsock);
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epoll_add(signalFd);
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for (;;) {
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int r = epoll_wait(epollfd, events, SOCK_QUEUE + 2, -1);
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if (r == -1) {
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if (errno == EINTR)
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continue;
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curl[i] = head[i];
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execute_list(i);
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else
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suicide("epoll_wait failed");
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}
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for (int i = 0; i < r; ++i) {
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int fd = events[i].data.fd;
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if (fd == lsock)
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accept_conns(&lsock);
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else if (fd == signalFd)
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signal_dispatch();
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else
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process_client_fd(fd);
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}
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close_idle_sk();
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}
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@ -875,7 +918,7 @@ int main(int argc, char** argv) {
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write_pid(pidfile);
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umask(077);
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fix_signals();
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setup_signals();
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/* If we are requested to update resolv.conf, preopen the fd before
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* we drop root privileges, making sure that if we create
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