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Use poll() instead of epoll() for ifchd and sockd.

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poll() is simpler, portable, and the scalability advantages of
epoll are inapplicable here.
This commit is contained in:
Nicholas J. Kain 2020-10-20 05:09:26 -04:00
parent 06a541261e
commit af9d45719f
2 changed files with 40 additions and 54 deletions
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47
src/ifchd.c
View File

@ -34,7 +34,7 @@
#include <sys/un.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <poll.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <fcntl.h>
@ -53,10 +53,6 @@
struct ifchd_client cl;
static int epollfd;
/* Slots are for the ndhc -> ifchd socket. */
static struct epoll_event events[2];
static int resolv_conf_fd = -1;
/* int ntp_conf_fd = -1; */
static int resolv_conf_head_fd = -1;
@ -341,36 +337,33 @@ static void process_client_socket(void)
static void do_ifch_work(void)
{
epollfd = epoll_create1(0);
if (epollfd < 0)
suicide("epoll_create1 failed");
cl.state = STATE_NOTHING;
memset(cl.ibuf, 0, sizeof cl.ibuf);
memset(cl.namesvrs, 0, sizeof cl.namesvrs);
memset(cl.domains, 0, sizeof cl.domains);
epoll_add(epollfd, ifchSock[1]);
epoll_add(epollfd, ifchStream[1]);
struct pollfd pfds[2] = {0};
pfds[0].fd = ifchSock[1];
pfds[0].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
pfds[1].fd = ifchStream[1];
pfds[1].events = POLLHUP|POLLERR|POLLRDHUP;
for (;;) {
int r = epoll_wait(epollfd, events, 2, -1);
if (r < 0) {
if (errno == EINTR)
continue;
else
suicide("epoll_wait failed");
if (poll(pfds, 2, -1) < 0) {
if (errno == EINTR) continue;
else suicide("pollt failed");
}
for (int i = 0; i < r; ++i) {
int fd = events[i].data.fd;
if (fd == ifchSock[1]) {
if (events[i].events & EPOLLIN)
process_client_socket();
} else if (fd == ifchStream[1]) {
if (events[i].events & (EPOLLHUP|EPOLLERR|EPOLLRDHUP))
exit(EXIT_SUCCESS);
} else
suicide("ifch: unexpected fd while performing epoll");
if (pfds[0].revents & POLLIN) {
pfds[0].revents &= ~POLLIN;
process_client_socket();
}
if (pfds[0].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
pfds[0].revents &= ~(POLLHUP|POLLERR|POLLRDHUP);
suicide("ifchSock closed unexpectedly");
}
if (pfds[1].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
pfds[1].revents &= ~(POLLHUP|POLLERR|POLLRDHUP);
exit(EXIT_SUCCESS);
}
}
}

47
src/sockd.c
View File

@ -36,7 +36,7 @@
#include <fcntl.h>
#include <assert.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <poll.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/prctl.h>
@ -58,10 +58,6 @@
#include "dhcp.h"
#include "sys.h"
static int epollfd;
/* Slots are for the ndhc -> ifchd socket. */
static struct epoll_event events[2];
uid_t sockd_uid = 0;
gid_t sockd_gid = 0;
@ -550,31 +546,28 @@ static void process_client_socket(void)
static void do_sockd_work(void)
{
epollfd = epoll_create1(0);
if (epollfd < 0)
suicide("epoll_create1 failed");
epoll_add(epollfd, sockdSock[1]);
epoll_add(epollfd, sockdStream[1]);
struct pollfd pfds[2] = {0};
pfds[0].fd = sockdSock[1];
pfds[0].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
pfds[1].fd = sockdStream[1];
pfds[1].events = POLLHUP|POLLERR|POLLRDHUP;
for (;;) {
int r = epoll_wait(epollfd, events, 2, -1);
if (r < 0) {
if (errno == EINTR)
continue;
else
suicide("epoll_wait failed");
if (poll(pfds, 2, -1) < 0) {
if (errno == EINTR) continue;
else suicide("poll failed");
}
for (int i = 0; i < r; ++i) {
int fd = events[i].data.fd;
if (fd == sockdSock[1]) {
if (events[i].events & EPOLLIN)
process_client_socket();
} else if (fd == sockdStream[1]) {
if (events[i].events & (EPOLLHUP|EPOLLERR|EPOLLRDHUP))
exit(EXIT_SUCCESS);
} else
suicide("sockd: unexpected fd while performing epoll");
if (pfds[0].revents & POLLIN) {
pfds[0].revents &= ~POLLIN;
process_client_socket();
}
if (pfds[0].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
pfds[0].revents &= ~(POLLHUP|POLLERR|POLLRDHUP);
suicide("sockdSock closed unexpectedly");
}
if (pfds[1].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
pfds[1].revents &= ~(POLLHUP|POLLERR|POLLRDHUP);
exit(EXIT_SUCCESS);
}
}
}