mirror of
https://github.com/omar-polo/gmid.git
synced 2024-10-01 23:11:14 +02:00
642 lines
13 KiB
C
642 lines
13 KiB
C
/*
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* Copyright (c) 2021 Omar Polo <op@omarpolo.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <netdb.h>
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include "gmid.h"
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int connected_clients;
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int
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check_path(struct client *c, const char *path, int *fd)
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{
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struct stat sb;
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assert(path != NULL);
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if ((*fd = openat(c->host->dirfd, *path ? path : ".",
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O_RDONLY | O_NOFOLLOW)) == -1) {
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return FILE_MISSING;
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}
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if (fstat(*fd, &sb) == -1) {
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LOGN(c, "failed stat for %s: %s", path, strerror(errno));
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return FILE_MISSING;
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}
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if (S_ISDIR(sb.st_mode))
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return FILE_DIRECTORY;
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if (sb.st_mode & S_IXUSR)
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return FILE_EXECUTABLE;
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return FILE_EXISTS;
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}
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int
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open_file(char *fpath, char *query, struct pollfd *fds, struct client *c)
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{
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switch (check_path(c, fpath, &c->fd)) {
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case FILE_EXECUTABLE:
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if (c->host->cgi != NULL && starts_with(fpath, c->host->cgi))
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return start_cgi(fpath, "", query, fds, c);
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/* fallthrough */
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case FILE_EXISTS:
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if ((c->len = filesize(c->fd)) == -1) {
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LOGE(c, "failed to get file size for %s", fpath);
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goodbye(fds, c);
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return 0;
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}
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if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
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c->fd, 0)) == MAP_FAILED) {
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LOGW(c, "mmap: %s: %s", fpath, strerror(errno));
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goodbye(fds, c);
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return 0;
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}
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c->i = c->buf;
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return start_reply(fds, c, SUCCESS, mime(fpath));
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case FILE_DIRECTORY:
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LOGD(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
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close(c->fd);
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c->fd = -1;
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send_dir(fpath, fds, c);
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return 0;
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case FILE_MISSING:
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if (c->host->cgi != NULL && starts_with(fpath, c->host->cgi))
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return check_for_cgi(fpath, query, fds, c);
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if (!start_reply(fds, c, NOT_FOUND, "not found"))
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return 0;
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goodbye(fds, c);
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return 0;
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default:
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/* unreachable */
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abort();
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}
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}
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/*
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* the inverse of this algorithm, i.e. starting from the start of the
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* path + strlen(cgi), and checking if each component, should be
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* faster. But it's tedious to write. This does the opposite: starts
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* from the end and strip one component at a time, until either an
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* executable is found or we emptied the path.
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*/
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int
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check_for_cgi(char *path, char *query, struct pollfd *fds, struct client *c)
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{
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char *end;
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end = strchr(path, '\0');
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/* NB: assume CGI is enabled and path matches cgi */
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while (end > path) {
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/* go up one level. UNIX paths are simple and POSIX
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* dirname, with its ambiguities on if the given path
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* is changed or not, gives me headaches. */
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while (*end != '/')
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end--;
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*end = '\0';
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switch (check_path(c, path, &c->fd)) {
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case FILE_EXECUTABLE:
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return start_cgi(path, end+1, query, fds,c);
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case FILE_MISSING:
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break;
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default:
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goto err;
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}
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*end = '/';
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end--;
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}
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err:
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if (!start_reply(fds, c, NOT_FOUND, "not found"))
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return 0;
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goodbye(fds, c);
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return 0;
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}
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void
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mark_nonblock(int fd)
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{
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int flags;
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if ((flags = fcntl(fd, F_GETFL)) == -1)
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fatal("fcntl(F_GETFL): %s", strerror(errno));
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if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
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fatal("fcntl(F_SETFL): %s", strerror(errno));
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}
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void
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handle_handshake(struct pollfd *fds, struct client *c)
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{
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struct vhost *h;
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const char *servname;
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switch (tls_handshake(c->ctx)) {
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case 0: /* success */
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case -1: /* already handshaked */
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break;
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case TLS_WANT_POLLIN:
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fds->events = POLLIN;
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return;
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case TLS_WANT_POLLOUT:
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fds->events = POLLOUT;
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return;
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default:
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/* unreachable */
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abort();
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}
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servname = tls_conn_servername(c->ctx);
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if (servname == NULL)
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goto hostnotfound;
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for (h = hosts; h->domain != NULL; ++h) {
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if (!strcmp(h->domain, servname) || !strcmp(h->domain, "*"))
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break;
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}
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if (h->domain != NULL) {
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c->state = S_OPEN;
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c->host = h;
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handle_open_conn(fds, c);
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return;
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}
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hostnotfound:
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/* XXX: check the correct response */
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if (!start_reply(fds, c, BAD_REQUEST, "Wrong host or missing SNI"))
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return;
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goodbye(fds, c);
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}
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void
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handle_open_conn(struct pollfd *fds, struct client *c)
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{
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char buf[GEMINI_URL_LEN];
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const char *parse_err = "invalid request";
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struct iri iri;
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bzero(buf, sizeof(buf));
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switch (tls_read(c->ctx, buf, sizeof(buf)-1)) {
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case -1:
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LOGE(c, "tls_read: %s", tls_error(c->ctx));
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goodbye(fds, c);
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return;
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case TLS_WANT_POLLIN:
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fds->events = POLLIN;
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return;
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case TLS_WANT_POLLOUT:
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fds->events = POLLOUT;
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return;
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}
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if (!trim_req_iri(buf) || !parse_iri(buf, &iri, &parse_err)) {
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if (!start_reply(fds, c, BAD_REQUEST, parse_err))
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return;
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goodbye(fds, c);
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return;
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}
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if (strcmp(iri.schema, "gemini") || iri.port_no != conf.port) {
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if (!start_reply(fds, c, PROXY_REFUSED, "won't proxy request"))
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return;
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goodbye(fds, c);
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return;
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}
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LOGI(c, "GET %s%s%s",
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*iri.path ? iri.path : "/",
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*iri.query ? "?" : "",
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*iri.query ? iri.query : "");
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send_file(iri.path, iri.query, fds, c);
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}
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int
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start_reply(struct pollfd *pfd, struct client *c, int code, const char *meta)
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{
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char buf[1030]; /* status + ' ' + max reply len + \r\n\0 */
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int len;
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c->code = code;
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c->meta = meta;
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c->state = S_INITIALIZING;
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snprintf(buf, sizeof(buf), "%d ", code);
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strlcat(buf, meta, sizeof(buf));
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if (!strcmp(meta, "text/gemini") && c->host->lang != NULL) {
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strlcat(buf, "; lang=", sizeof(buf));
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strlcat(buf, c->host->lang, sizeof(buf));
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}
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len = strlcat(buf, "\r\n", sizeof(buf));
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assert(len < (int)sizeof(buf));
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switch (tls_write(c->ctx, buf, len)) {
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case TLS_WANT_POLLIN:
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pfd->events = POLLIN;
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return 0;
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case TLS_WANT_POLLOUT:
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pfd->events = POLLOUT;
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return 0;
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default:
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return 1;
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}
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}
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int
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start_cgi(const char *spath, const char *relpath, const char *query,
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struct pollfd *fds, struct client *c)
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{
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char addr[NI_MAXHOST];
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const char *ruser, *cissuer, *chash;
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int e;
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e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
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addr, sizeof(addr),
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NULL, 0,
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NI_NUMERICHOST);
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if (e != 0)
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goto err;
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if (tls_peer_cert_provided(c->ctx)) {
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ruser = tls_peer_cert_subject(c->ctx);
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cissuer = tls_peer_cert_issuer(c->ctx);
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chash = tls_peer_cert_hash(c->ctx);
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} else {
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ruser = NULL;
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cissuer = NULL;
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chash = NULL;
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}
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if (!send_string(exfd, spath)
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|| !send_string(exfd, relpath)
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|| !send_string(exfd, query)
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|| !send_string(exfd, addr)
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|| !send_string(exfd, ruser)
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|| !send_string(exfd, cissuer)
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|| !send_string(exfd, chash)
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|| !send_vhost(exfd, c->host))
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goto err;
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close(c->fd);
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if ((c->fd = recv_fd(exfd)) == -1) {
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if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
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return 0;
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goodbye(fds, c);
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return 0;
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}
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c->child = 1;
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c->state = S_SENDING;
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cgi_poll_on_child(fds, c);
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/* handle_cgi(fds, c); */
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return 0;
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err:
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/* fatal("cannot talk to the executor process: %s", strerror(errno)); */
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fatal("cannot talk to the executor process");
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}
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void
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send_file(char *path, char *query, struct pollfd *fds, struct client *c)
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{
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ssize_t ret, len;
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if (c->fd == -1) {
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if (!open_file(path, query, fds, c))
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return;
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c->state = S_SENDING;
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}
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len = (c->buf + c->len) - c->i;
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while (len > 0) {
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switch (ret = tls_write(c->ctx, c->i, len)) {
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case -1:
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LOGE(c, "tls_write: %s", tls_error(c->ctx));
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goodbye(fds, c);
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return;
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case TLS_WANT_POLLIN:
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fds->events = POLLIN;
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return;
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case TLS_WANT_POLLOUT:
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fds->events = POLLOUT;
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return;
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default:
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c->i += ret;
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len -= ret;
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break;
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}
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}
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goodbye(fds, c);
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}
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void
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send_dir(char *path, struct pollfd *fds, struct client *client)
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{
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char fpath[PATHBUF];
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size_t len;
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bzero(fpath, PATHBUF);
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if (path[0] != '.')
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fpath[0] = '.';
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/* this cannot fail since sizeof(fpath) > maxlen of path */
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strlcat(fpath, path, PATHBUF);
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len = strlen(fpath);
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/* add a trailing / in case. */
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if (fpath[len-1] != '/') {
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fpath[len] = '/';
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}
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strlcat(fpath, "index.gmi", sizeof(fpath));
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send_file(fpath, NULL, fds, client);
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}
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void
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cgi_poll_on_child(struct pollfd *fds, struct client *c)
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{
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int fd;
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if (c->waiting_on_child)
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return;
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c->waiting_on_child = 1;
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fds->events = POLLIN;
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fd = fds->fd;
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fds->fd = c->fd;
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c->fd = fd;
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}
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void
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cgi_poll_on_client(struct pollfd *fds, struct client *c)
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{
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int fd;
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if (!c->waiting_on_child)
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return;
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c->waiting_on_child = 0;
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fd = fds->fd;
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fds->fd = c->fd;
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c->fd = fd;
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}
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void
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handle_cgi(struct pollfd *fds, struct client *c)
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{
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ssize_t r;
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/* ensure c->fd is the child and fds->fd the client */
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cgi_poll_on_client(fds, c);
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while (1) {
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if (c->len == 0) {
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if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
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goto end;
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if (r == -1) {
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if (errno == EAGAIN || errno == EWOULDBLOCK) {
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cgi_poll_on_child(fds, c);
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return;
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}
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goto end;
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}
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c->len = r;
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c->off = 0;
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}
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while (c->len > 0) {
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switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
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case -1:
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goto end;
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case TLS_WANT_POLLOUT:
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fds->events = POLLOUT;
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return;
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case TLS_WANT_POLLIN:
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fds->events = POLLIN;
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return;
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default:
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c->off += r;
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c->len -= r;
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break;
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}
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}
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}
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end:
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goodbye(fds, c);
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}
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void
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goodbye(struct pollfd *pfd, struct client *c)
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{
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c->state = S_CLOSING;
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switch (tls_close(c->ctx)) {
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case TLS_WANT_POLLIN:
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pfd->events = POLLIN;
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return;
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case TLS_WANT_POLLOUT:
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pfd->events = POLLOUT;
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return;
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}
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connected_clients--;
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tls_free(c->ctx);
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c->ctx = NULL;
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if (c->buf != MAP_FAILED)
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munmap(c->buf, c->len);
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if (c->fd != -1)
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close(c->fd);
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close(pfd->fd);
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pfd->fd = -1;
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}
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void
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do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
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{
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int i, fd;
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struct sockaddr_storage addr;
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socklen_t len;
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len = sizeof(addr);
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if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
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if (errno == EWOULDBLOCK)
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return;
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fatal("accept: %s", strerror(errno));
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}
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mark_nonblock(fd);
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for (i = 0; i < MAX_USERS; ++i) {
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if (fds[i].fd == -1) {
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bzero(&clients[i], sizeof(struct client));
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if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
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break; /* goodbye fd! */
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fds[i].fd = fd;
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fds[i].events = POLLIN;
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clients[i].state = S_HANDSHAKE;
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clients[i].fd = -1;
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clients[i].child = 0;
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clients[i].waiting_on_child = 0;
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clients[i].buf = MAP_FAILED;
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clients[i].af = AF_INET;
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clients[i].addr = addr;
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connected_clients++;
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return;
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}
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}
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close(fd);
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}
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void
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handle(struct pollfd *fds, struct client *client)
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{
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switch (client->state) {
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case S_HANDSHAKE:
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handle_handshake(fds, client);
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break;
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case S_OPEN:
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handle_open_conn(fds, client);
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break;
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case S_INITIALIZING:
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if (!start_reply(fds, client, client->code, client->meta))
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return;
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if (client->code != SUCCESS) {
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|
/* we don't need a body */
|
|
goodbye(fds, client);
|
|
return;
|
|
}
|
|
|
|
client->state = S_SENDING;
|
|
|
|
/* fallthrough */
|
|
|
|
case S_SENDING:
|
|
if (client->child)
|
|
handle_cgi(fds, client);
|
|
else
|
|
send_file(NULL, NULL, fds, client);
|
|
break;
|
|
|
|
case S_CLOSING:
|
|
goodbye(fds, client);
|
|
break;
|
|
|
|
default:
|
|
/* unreachable */
|
|
abort();
|
|
}
|
|
}
|
|
|
|
void
|
|
loop(struct tls *ctx, int sock4, int sock6)
|
|
{
|
|
int i;
|
|
struct client clients[MAX_USERS];
|
|
struct pollfd fds[MAX_USERS];
|
|
|
|
connected_clients = 0;
|
|
|
|
for (i = 0; i < MAX_USERS; ++i) {
|
|
fds[i].fd = -1;
|
|
fds[i].events = POLLIN;
|
|
bzero(&clients[i], sizeof(struct client));
|
|
}
|
|
|
|
fds[0].fd = sock4;
|
|
fds[1].fd = sock6;
|
|
|
|
for (;;) {
|
|
if (poll(fds, MAX_USERS, INFTIM) == -1) {
|
|
if (errno == EINTR) {
|
|
fprintf(stderr, "connected clients: %d\n",
|
|
connected_clients);
|
|
continue;
|
|
}
|
|
fatal("poll: %s", strerror(errno));
|
|
}
|
|
|
|
for (i = 0; i < MAX_USERS; i++) {
|
|
if (fds[i].revents == 0)
|
|
continue;
|
|
|
|
if (fds[i].revents & (POLLERR|POLLNVAL))
|
|
fatal("bad fd %d: %s", fds[i].fd,
|
|
strerror(errno));
|
|
|
|
if (fds[i].revents & POLLHUP) {
|
|
/* fds[i] may be the fd of the stdin
|
|
* of a cgi script that has exited. */
|
|
if (!clients[i].waiting_on_child) {
|
|
goodbye(&fds[i], &clients[i]);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (fds[i].fd == sock4)
|
|
do_accept(sock4, ctx, fds, clients);
|
|
else if (fds[i].fd == sock6)
|
|
do_accept(sock6, ctx, fds, clients);
|
|
else
|
|
handle(&fds[i], &clients[i]);
|
|
}
|
|
}
|
|
}
|