mirror of https://github.com/mirror/busybox.git
145 lines
3.1 KiB
C
145 lines
3.1 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Fake identd server.
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*
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* Copyright (C) 2007 Denis Vlasenko
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include <syslog.h>
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#include "busybox.h"
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#include "isrv.h"
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enum { TIMEOUT = 20 };
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/* Why use alarm(TIMEOUT-1)?
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* isrv's internal select() will run with timeout=TIMEOUT.
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* If nothing happens during TIMEOUT-1 seconds (no accept/read),
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* then ALL sessions timed out by now. Instead of closing them one-by-one
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* (isrv calls do_timeout for each 'stale' session),
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* SIGALRM triggered by alarm(TIMEOUT-1) will kill us, terminating them all.
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*/
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typedef struct identd_buf_t {
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int pos;
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int fd_flag;
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char buf[64 - 2*sizeof(int)];
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} identd_buf_t;
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static const char *bogouser = "nobody";
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static int new_peer(isrv_state_t *state, int fd)
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{
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int peer;
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identd_buf_t *buf = xzalloc(sizeof(*buf));
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alarm(TIMEOUT - 1);
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peer = isrv_register_peer(state, buf);
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if (peer < 0)
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return 0; /* failure */
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if (isrv_register_fd(state, peer, fd) < 0)
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return peer; /* failure, unregister peer */
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buf->fd_flag = fcntl(fd, F_GETFL, 0) | O_NONBLOCK;
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isrv_want_rd(state, fd);
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return 0;
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}
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static int do_rd(int fd, void **paramp)
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{
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identd_buf_t *buf = *paramp;
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char *cur, *p;
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int sz;
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alarm(TIMEOUT - 1);
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cur = buf->buf + buf->pos;
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fcntl(fd, F_SETFL, buf->fd_flag | O_NONBLOCK);
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sz = safe_read(fd, cur, sizeof(buf->buf) - buf->pos);
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if (sz < 0) {
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if (errno != EAGAIN)
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goto term; /* terminate this session if !EAGAIN */
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goto ok;
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}
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buf->pos += sz;
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buf->buf[buf->pos] = '\0';
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p = strpbrk(cur, "\r\n");
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if (p)
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*p = '\0';
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if (p || !sz || buf->pos == sizeof(buf->buf)) {
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/* fd is still in nonblocking mode - we never block here */
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fdprintf(fd, "%s : USERID : UNIX : %s\r\n", buf->buf, bogouser);
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goto term;
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}
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ok:
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fcntl(fd, F_SETFL, buf->fd_flag & ~O_NONBLOCK);
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return 0;
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term:
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fcntl(fd, F_SETFL, buf->fd_flag & ~O_NONBLOCK);
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free(buf);
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return 1;
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}
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static int do_timeout(void **paramp)
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{
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return 1; /* terminate session */
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}
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static void inetd_mode(void)
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{
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identd_buf_t *buf = xzalloc(sizeof(*buf));
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/* We do NOT want nonblocking I/O here! */
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buf->fd_flag = fcntl(0, F_GETFL, 0);
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while (do_rd(0, (void*)&buf) == 0) /* repeat */;
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}
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int fakeidentd_main(int argc, char **argv)
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{
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enum {
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OPT_foreground = 0x1,
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OPT_inetd = 0x2,
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OPT_inetdwait = 0x4,
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OPT_nodeamon = 0x7,
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OPT_bindaddr = 0x8,
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};
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const char *bind_address = NULL;
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unsigned opt;
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int fd;
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opt = getopt32(argc, argv, "fiwb:", &bind_address);
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if (optind < argc)
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bogouser = argv[optind];
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/* Daemonize if no -f or -i or -w */
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bb_sanitize_stdio(!(opt & OPT_nodeamon));
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if (!(opt & OPT_nodeamon)) {
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openlog(applet_name, 0, LOG_DAEMON);
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logmode = LOGMODE_SYSLOG;
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}
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if (opt & OPT_inetd) {
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inetd_mode();
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return 0;
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}
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/* Ignore closed connections when writing */
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signal(SIGPIPE, SIG_IGN);
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if (opt & OPT_inetdwait) {
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fd = 0;
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} else {
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fd = create_and_bind_stream_or_die(bind_address,
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bb_lookup_port("identd", "tcp", 113));
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xlisten(fd, 5);
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}
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isrv_run(fd, new_peer, do_rd, NULL, do_timeout, TIMEOUT, 1);
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return 0;
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}
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