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https://github.com/jart/cosmopolitan.git
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Add libresolv from Musl Libc
Locally modified to get nameservers from Windows Registry when `\etc\resolv.conf` isn't defined.
This commit is contained in:
Justine Tunney
parent
8874a37abc
commit
1a96de6eda
36 changed files with 2313 additions and 73 deletions
363
third_party/musl/res_msend.c
vendored
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363
third_party/musl/res_msend.c
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@ -0,0 +1,363 @@
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/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│ vi: set noet ft=c ts=8 tw=8 fenc=utf-8 :vi │
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╚──────────────────────────────────────────────────────────────────────────────╝
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│ │
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│ Musl Libc │
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│ Copyright © 2005-2014 Rich Felker, et al. │
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│ │
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│ Permission is hereby granted, free of charge, to any person obtaining │
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│ a copy of this software and associated documentation files (the │
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│ "Software"), to deal in the Software without restriction, including │
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│ without limitation the rights to use, copy, modify, merge, publish, │
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│ distribute, sublicense, and/or sell copies of the Software, and to │
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│ permit persons to whom the Software is furnished to do so, subject to │
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│ the following conditions: │
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│ │
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│ The above copyright notice and this permission notice shall be │
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│ included in all copies or substantial portions of the Software. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
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│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
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│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
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│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/sock/struct/pollfd.h"
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#include "libc/calls/struct/timespec.h"
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#include "libc/sysv/consts/clock.h"
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#include "libc/calls/calls.h"
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#include "libc/errno.h"
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#include "libc/sock/struct/msghdr.h"
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#include "libc/sysv/consts/poll.h"
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#include "libc/sysv/consts/tcp.h"
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#include "libc/sysv/consts/msg.h"
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#include "libc/sysv/consts/af.h"
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#include "libc/thread/thread.h"
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#include "libc/str/str.h"
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#include "libc/calls/weirdtypes.h"
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#include "libc/sysv/consts/sock.h"
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#include "libc/sysv/consts/ipproto.h"
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#include "libc/sysv/consts/ipv6.h"
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#include "lookup.internal.h"
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asm(".ident\t\"\\n\\n\
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Musl libc (MIT License)\\n\
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Copyright 2005-2014 Rich Felker, et. al.\"");
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asm(".include \"libc/disclaimer.inc\"");
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static void cleanup(void *p)
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{
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struct pollfd *pfd = p;
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for (int i=0; pfd[i].fd >= -1; i++)
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if (pfd[i].fd >= 0)
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close(pfd[i].fd);
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}
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static unsigned long mtime()
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{
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struct timespec ts;
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if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0 && errno == ENOSYS)
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clock_gettime(CLOCK_REALTIME, &ts);
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return (unsigned long)ts.tv_sec * 1000
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+ ts.tv_nsec / 1000000;
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}
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static int start_tcp(struct pollfd *pfd, int family, const void *sa, socklen_t sl, const unsigned char *q, int ql)
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{
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struct msghdr mh = {
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.msg_name = (void *)sa,
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.msg_namelen = sl,
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.msg_iovlen = 2,
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.msg_iov = (struct iovec [2]){
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{ .iov_base = (uint8_t[]){ ql>>8, ql }, .iov_len = 2 },
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{ .iov_base = (void *)q, .iov_len = ql } }
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};
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int r;
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int fd = socket(family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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pfd->fd = fd;
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pfd->events = POLLOUT;
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if (!setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN_CONNECT,
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&(int){1}, sizeof(int))) {
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r = sendmsg(fd, &mh, MSG_FASTOPEN|MSG_NOSIGNAL);
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if (r == ql+2) pfd->events = POLLIN;
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if (r >= 0) return r;
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if (errno == EINPROGRESS) return 0;
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}
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r = connect(fd, sa, sl);
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if (!r || errno == EINPROGRESS) return 0;
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close(fd);
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pfd->fd = -1;
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return -1;
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}
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static void step_mh(struct msghdr *mh, size_t n)
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{
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/* Adjust iovec in msghdr to skip first n bytes. */
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while (mh->msg_iovlen && n >= mh->msg_iov->iov_len) {
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n -= mh->msg_iov->iov_len;
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mh->msg_iov++;
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mh->msg_iovlen--;
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}
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if (!mh->msg_iovlen) return;
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mh->msg_iov->iov_base = (char *)mh->msg_iov->iov_base + n;
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mh->msg_iov->iov_len -= n;
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}
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/* Internal contract for __res_msend[_rc]: asize must be >=512, nqueries
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* must be sufficiently small to be safe as VLA size. In practice it's
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* either 1 or 2, anyway. */
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int __res_msend_rc(int nqueries, const unsigned char *const *queries,
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const int *qlens, unsigned char *const *answers, int *alens, int asize,
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const struct resolvconf *conf)
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{
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int fd;
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int timeout, attempts, retry_interval, servfail_retry = 0;
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union {
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struct sockaddr_in sin;
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struct sockaddr_in6 sin6;
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} sa = {0}, ns[MAXNS] = {0};
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socklen_t sl = sizeof sa.sin;
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int nns = 0;
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int family = AF_INET;
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int rlen;
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int next;
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int i, j;
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int cs;
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struct pollfd pfd[nqueries+2];
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int qpos[nqueries], apos[nqueries];
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unsigned char alen_buf[nqueries][2];
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int r;
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unsigned long t0, t1, t2;
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pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
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timeout = 1000*conf->timeout;
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attempts = conf->attempts;
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for (nns=0; nns<conf->nns; nns++) {
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const struct address *iplit = &conf->ns[nns];
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if (iplit->family == AF_INET) {
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memcpy(&ns[nns].sin.sin_addr, iplit->addr, 4);
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ns[nns].sin.sin_port = htons(53);
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ns[nns].sin.sin_family = AF_INET;
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} else {
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sl = sizeof sa.sin6;
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memcpy(&ns[nns].sin6.sin6_addr, iplit->addr, 16);
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ns[nns].sin6.sin6_port = htons(53);
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ns[nns].sin6.sin6_scope_id = iplit->scopeid;
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ns[nns].sin6.sin6_family = family = AF_INET6;
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}
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}
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/* Get local address and open/bind a socket */
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fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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/* Handle case where system lacks IPv6 support */
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if (fd < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
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for (i=0; i<nns && conf->ns[nns].family == AF_INET6; i++);
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if (i==nns) {
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pthread_setcancelstate(cs, 0);
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return -1;
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}
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fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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family = AF_INET;
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sl = sizeof sa.sin;
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}
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/* Convert any IPv4 addresses in a mixed environment to v4-mapped */
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if (fd >= 0 && family == AF_INET6) {
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setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0);
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for (i=0; i<nns; i++) {
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if (ns[i].sin.sin_family != AF_INET) continue;
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memcpy(ns[i].sin6.sin6_addr.s6_addr+12,
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&ns[i].sin.sin_addr, 4);
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memcpy(ns[i].sin6.sin6_addr.s6_addr,
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"\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
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ns[i].sin6.sin6_family = AF_INET6;
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ns[i].sin6.sin6_flowinfo = 0;
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ns[i].sin6.sin6_scope_id = 0;
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}
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}
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sa.sin.sin_family = family;
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if (fd < 0 || bind(fd, (void *)&sa, sl) < 0) {
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if (fd >= 0) close(fd);
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pthread_setcancelstate(cs, 0);
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return -1;
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}
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/* Past this point, there are no errors. Each individual query will
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* yield either no reply (indicated by zero length) or an answer
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* packet which is up to the caller to interpret. */
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for (i=0; i<nqueries; i++) pfd[i].fd = -1;
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pfd[nqueries].fd = fd;
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pfd[nqueries].events = POLLIN;
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pfd[nqueries+1].fd = -2;
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pthread_cleanup_push(cleanup, pfd);
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pthread_setcancelstate(cs, 0);
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memset(alens, 0, sizeof *alens * nqueries);
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retry_interval = timeout / attempts;
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next = 0;
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t0 = t2 = mtime();
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t1 = t2 - retry_interval;
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for (; t2-t0 < timeout; t2=mtime()) {
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/* This is the loop exit condition: that all queries
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* have an accepted answer. */
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for (i=0; i<nqueries && alens[i]>0; i++);
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if (i==nqueries) break;
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if (t2-t1 >= retry_interval) {
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/* Query all configured namservers in parallel */
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for (i=0; i<nqueries; i++)
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if (!alens[i])
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for (j=0; j<nns; j++)
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sendto(fd, queries[i],
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qlens[i], MSG_NOSIGNAL,
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(void *)&ns[j], sl);
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t1 = t2;
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servfail_retry = 2 * nqueries;
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}
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/* Wait for a response, or until time to retry */
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if (poll(pfd, nqueries+1, t1+retry_interval-t2) <= 0) continue;
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while (next < nqueries) {
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struct msghdr mh = {
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.msg_name = (void *)&sa,
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.msg_namelen = sl,
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.msg_iovlen = 1,
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.msg_iov = (struct iovec []){
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{ .iov_base = (void *)answers[next],
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.iov_len = asize }
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}
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};
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rlen = recvmsg(fd, &mh, 0);
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if (rlen < 0) break;
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/* Ignore non-identifiable packets */
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if (rlen < 4) continue;
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/* Ignore replies from addresses we didn't send to */
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for (j=0; j<nns && memcmp(ns+j, &sa, sl); j++);
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if (j==nns) continue;
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/* Find which query this answer goes with, if any */
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for (i=next; i<nqueries && (
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answers[next][0] != queries[i][0] ||
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answers[next][1] != queries[i][1] ); i++);
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if (i==nqueries) continue;
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if (alens[i]) continue;
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/* Only accept positive or negative responses;
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* retry immediately on server failure, and ignore
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* all other codes such as refusal. */
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switch (answers[next][3] & 15) {
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case 0:
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case 3:
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break;
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case 2:
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if (servfail_retry && servfail_retry--)
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sendto(fd, queries[i],
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qlens[i], MSG_NOSIGNAL,
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(void *)&ns[j], sl);
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default:
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continue;
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}
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/* Store answer in the right slot, or update next
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* available temp slot if it's already in place. */
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alens[i] = rlen;
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if (i == next)
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for (; next<nqueries && alens[next]; next++);
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else
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memcpy(answers[i], answers[next], rlen);
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/* Ignore further UDP if all slots full or TCP-mode */
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if (next == nqueries) pfd[nqueries].events = 0;
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/* If answer is truncated (TC bit), fallback to TCP */
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if ((answers[i][2] & 2) || (mh.msg_flags & MSG_TRUNC)) {
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alens[i] = -1;
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pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, 0);
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r = start_tcp(pfd+i, family, ns+j, sl, queries[i], qlens[i]);
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pthread_setcancelstate(cs, 0);
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if (r >= 0) {
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qpos[i] = r;
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apos[i] = 0;
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}
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continue;
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}
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}
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for (i=0; i<nqueries; i++) {
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if (pfd[i].revents & POLLOUT) {
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struct msghdr mh = {
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.msg_iovlen = 2,
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.msg_iov = (struct iovec [2]){
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{ .iov_base = (uint8_t[]){ qlens[i]>>8, qlens[i] }, .iov_len = 2 },
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{ .iov_base = (void *)queries[i], .iov_len = qlens[i] } }
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};
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step_mh(&mh, qpos[i]);
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r = sendmsg(pfd[i].fd, &mh, MSG_NOSIGNAL);
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if (r < 0) goto out;
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qpos[i] += r;
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if (qpos[i] == qlens[i]+2)
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pfd[i].events = POLLIN;
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}
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}
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for (i=0; i<nqueries; i++) {
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if (pfd[i].revents & POLLIN) {
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struct msghdr mh = {
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.msg_iovlen = 2,
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.msg_iov = (struct iovec [2]){
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{ .iov_base = alen_buf[i], .iov_len = 2 },
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{ .iov_base = answers[i], .iov_len = asize } }
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};
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step_mh(&mh, apos[i]);
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r = recvmsg(pfd[i].fd, &mh, 0);
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if (r <= 0) goto out;
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apos[i] += r;
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if (apos[i] < 2) continue;
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int alen = alen_buf[i][0]*256 + alen_buf[i][1];
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if (alen < 13) goto out;
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if (apos[i] < alen+2 && apos[i] < asize+2)
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continue;
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int rcode = answers[i][3] & 15;
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if (rcode != 0 && rcode != 3)
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goto out;
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/* Storing the length here commits the accepted answer.
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* Immediately close TCP socket so as not to consume
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* resources we no longer need. */
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alens[i] = alen;
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close(pfd[i].fd);
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pfd[i].fd = -1;
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}
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}
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}
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out:
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pthread_cleanup_pop(1);
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/* Disregard any incomplete TCP results */
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for (i=0; i<nqueries; i++) if (alens[i]<0) alens[i] = 0;
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return 0;
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}
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int __res_msend(int nqueries, const unsigned char *const *queries,
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const int *qlens, unsigned char *const *answers, int *alens, int asize)
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{
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struct resolvconf conf;
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if (__get_resolv_conf(&conf, 0, 0) < 0) return -1;
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return __res_msend_rc(nqueries, queries, qlens, answers, alens, asize, &conf);
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}
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