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move dns lookups to its own (privilege revoking, not chrooting) process.
reason: the parent process must never ever block, but the dns routines can. last not least this fixes ntpd -s 'hanging' for a long time. tested by a couple of peopleOPENBSD_4_5
henning
16 years ago
4 changed files with 245 additions and 13 deletions
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Diff Options
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+2 -2src/usr.sbin/ntpd/Makefile
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+69 -10src/usr.sbin/ntpd/ntp.c
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+170 -0src/usr.sbin/ntpd/ntp_dns.c
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+4 -1src/usr.sbin/ntpd/ntpd.h
+ 2
- 2
src/usr.sbin/ntpd/Makefile
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+ 69
- 10
src/usr.sbin/ntpd/ntp.c
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+ 170
- 0
src/usr.sbin/ntpd/ntp_dns.c
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| @ -0,0 +1,170 @@ | |||||
| /* $OpenBSD: ntp_dns.c,v 1.1 2008/09/12 10:46:09 henning Exp $ */ | |||||
| /* | |||||
| * Copyright (c) 2003-2008 Henning Brauer <henning@openbsd.org> | |||||
| * | |||||
| * Permission to use, copy, modify, and distribute this software for any | |||||
| * purpose with or without fee is hereby granted, provided that the above | |||||
| * copyright notice and this permission notice appear in all copies. | |||||
| * | |||||
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |||||
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |||||
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |||||
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |||||
| * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER | |||||
| * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING | |||||
| * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |||||
| */ | |||||
| #include <sys/param.h> | |||||
| #include <sys/time.h> | |||||
| #include <errno.h> | |||||
| #include <poll.h> | |||||
| #include <signal.h> | |||||
| #include <stdlib.h> | |||||
| #include <string.h> | |||||
| #include <unistd.h> | |||||
| #include "ntpd.h" | |||||
| volatile sig_atomic_t quit_dns = 0; | |||||
| struct imsgbuf *ibuf_dns; | |||||
| void sighdlr_dns(int); | |||||
| int dns_dispatch_imsg(void); | |||||
| void | |||||
| sighdlr_dns(int sig) | |||||
| { | |||||
| switch (sig) { | |||||
| case SIGTERM: | |||||
| case SIGINT: | |||||
| quit_dns = 1; | |||||
| break; | |||||
| } | |||||
| } | |||||
| pid_t | |||||
| ntp_dns(int pipe_ntp[2], struct ntpd_conf *nconf, struct passwd *pw) | |||||
| { | |||||
| pid_t pid; | |||||
| struct pollfd pfd[1]; | |||||
| int nfds; | |||||
| switch (pid = fork()) { | |||||
| case -1: | |||||
| fatal("cannot fork"); | |||||
| break; | |||||
| case 0: | |||||
| break; | |||||
| default: | |||||
| return (pid); | |||||
| } | |||||
| /* in this case the parent didn't init logging and didn't daemonize */ | |||||
| if (nconf->settime && !nconf->debug) { | |||||
| log_init(nconf->debug); | |||||
| if (setsid() == -1) | |||||
| fatal("setsid"); | |||||
| } | |||||
| setproctitle("dns engine"); | |||||
| close(pipe_ntp[0]); | |||||
| if (setgroups(1, &pw->pw_gid) || | |||||
| setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || | |||||
| setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) | |||||
| fatal("can't drop privileges"); | |||||
| endservent(); | |||||
| signal(SIGTERM, sighdlr_dns); | |||||
| signal(SIGINT, sighdlr_dns); | |||||
| signal(SIGHUP, sighdlr_dns); | |||||
| if ((ibuf_dns = malloc(sizeof(struct imsgbuf))) == NULL) | |||||
| fatal(NULL); | |||||
| imsg_init(ibuf_dns, pipe_ntp[1]); | |||||
| while (quit_dns == 0) { | |||||
| pfd[0].fd = ibuf_dns->fd; | |||||
| pfd[0].events = POLLIN; | |||||
| if (ibuf_dns->w.queued) | |||||
| pfd[0].events |= POLLOUT; | |||||
| if ((nfds = poll(pfd, 1, INFTIM)) == -1) | |||||
| if (errno != EINTR) { | |||||
| log_warn("poll error"); | |||||
| quit_dns = 1; | |||||
| } | |||||
| if (nfds > 0 && (pfd[0].revents & POLLOUT)) | |||||
| if (msgbuf_write(&ibuf_dns->w) < 0) { | |||||
| log_warn("pipe write error (to ntp engine)"); | |||||
| quit_dns = 1; | |||||
| } | |||||
| if (nfds > 0 && pfd[0].revents & POLLIN) { | |||||
| nfds--; | |||||
| if (dns_dispatch_imsg() == -1) | |||||
| quit_dns = 1; | |||||
| } | |||||
| } | |||||
| msgbuf_clear(&ibuf_dns->w); | |||||
| free(ibuf_dns); | |||||
| _exit(0); | |||||
| } | |||||
| int | |||||
| dns_dispatch_imsg(void) | |||||
| { | |||||
| struct imsg imsg; | |||||
| int n, cnt; | |||||
| char *name; | |||||
| struct ntp_addr *h, *hn; | |||||
| struct buf *buf; | |||||
| if ((n = imsg_read(ibuf_dns)) == -1) | |||||
| return (-1); | |||||
| if (n == 0) { /* connection closed */ | |||||
| log_warnx("dispatch_imsg in main: pipe closed"); | |||||
| return (-1); | |||||
| } | |||||
| for (;;) { | |||||
| if ((n = imsg_get(ibuf_dns, &imsg)) == -1) | |||||
| return (-1); | |||||
| if (n == 0) | |||||
| break; | |||||
| switch (imsg.hdr.type) { | |||||
| case IMSG_HOST_DNS: | |||||
| name = imsg.data; | |||||
| if (imsg.hdr.len < 1 + IMSG_HEADER_SIZE) | |||||
| fatalx("invalid IMSG_HOST_DNS received"); | |||||
| imsg.hdr.len -= 1 + IMSG_HEADER_SIZE; | |||||
| if (name[imsg.hdr.len] != '\0' || | |||||
| strlen(name) != imsg.hdr.len) | |||||
| fatalx("invalid IMSG_HOST_DNS received"); | |||||
| if ((cnt = host_dns(name, &hn)) == -1) | |||||
| break; | |||||
| buf = imsg_create(ibuf_dns, IMSG_HOST_DNS, | |||||
| imsg.hdr.peerid, 0, | |||||
| cnt * sizeof(struct sockaddr_storage)); | |||||
| if (buf == NULL) | |||||
| break; | |||||
| if (cnt > 0) | |||||
| for (h = hn; h != NULL; h = h->next) | |||||
| imsg_add(buf, &h->ss, sizeof(h->ss)); | |||||
| imsg_close(ibuf_dns, buf); | |||||
| break; | |||||
| default: | |||||
| break; | |||||
| } | |||||
| imsg_free(&imsg); | |||||
| } | |||||
| return (0); | |||||
| } | |||||