| /* vi: set sw=4 ts=4: */ |
| /* |
| * Fake identd server. |
| * |
| * Copyright (C) 2007 Denis Vlasenko |
| * |
| * Licensed under GPL version 2, see file LICENSE in this tarball for details. |
| */ |
| |
| #include <syslog.h> |
| #include "busybox.h" |
| #include "isrv.h" |
| |
| enum { TIMEOUT = 20 }; |
| |
| typedef struct identd_buf_t { |
| int pos; |
| int fd_flag; |
| char buf[64 - 2*sizeof(int)]; |
| } identd_buf_t; |
| |
| static const char *bogouser = "nobody"; |
| |
| static int new_peer(isrv_state_t *state, int fd) |
| { |
| int peer; |
| identd_buf_t *buf = xzalloc(sizeof(*buf)); |
| |
| peer = isrv_register_peer(state, buf); |
| if (peer < 0) |
| return 0; /* failure */ |
| if (isrv_register_fd(state, peer, fd) < 0) |
| return peer; /* failure, unregister peer */ |
| |
| buf->fd_flag = fcntl(fd, F_GETFL, 0) | O_NONBLOCK; |
| isrv_want_rd(state, fd); |
| return 0; |
| } |
| |
| static int do_rd(int fd, void **paramp) |
| { |
| identd_buf_t *buf = *paramp; |
| char *cur, *p; |
| int retval = 0; /* session is ok (so far) */ |
| int sz; |
| |
| cur = buf->buf + buf->pos; |
| |
| if (buf->fd_flag & O_NONBLOCK) |
| fcntl(fd, F_SETFL, buf->fd_flag); |
| sz = safe_read(fd, cur, sizeof(buf->buf) - buf->pos); |
| |
| if (sz < 0) { |
| if (errno != EAGAIN) |
| goto term; /* terminate this session if !EAGAIN */ |
| goto ok; |
| } |
| |
| buf->pos += sz; |
| buf->buf[buf->pos] = '\0'; |
| p = strpbrk(cur, "\r\n"); |
| if (p) |
| *p = '\0'; |
| if (!p && sz && buf->pos <= sizeof(buf->buf)) |
| goto ok; |
| /* Terminate session. If we are in server mode, then |
| * fd is still in nonblocking mode - we never block here */ |
| if (fd == 0) fd++; /* inetd mode? then write to fd 1 */ |
| fdprintf(fd, "%s : USERID : UNIX : %s\r\n", buf->buf, bogouser); |
| term: |
| free(buf); |
| retval = 1; /* terminate */ |
| ok: |
| if (buf->fd_flag & O_NONBLOCK) |
| fcntl(fd, F_SETFL, buf->fd_flag & ~O_NONBLOCK); |
| return retval; |
| } |
| |
| static int do_timeout(void **paramp) |
| { |
| return 1; /* terminate session */ |
| } |
| |
| static void inetd_mode(void) |
| { |
| identd_buf_t *buf = xzalloc(sizeof(*buf)); |
| /* buf->pos = 0; - xzalloc did it */ |
| /* We do NOT want nonblocking I/O here! */ |
| /* buf->fd_flag = 0; - xzalloc did it */ |
| do |
| alarm(TIMEOUT); |
| while (do_rd(0, (void*)&buf) == 0); |
| } |
| |
| int fakeidentd_main(int argc, char **argv) |
| { |
| enum { |
| OPT_foreground = 0x1, |
| OPT_inetd = 0x2, |
| OPT_inetdwait = 0x4, |
| OPT_fiw = 0x7, |
| OPT_bindaddr = 0x8, |
| }; |
| |
| const char *bind_address = NULL; |
| unsigned opt; |
| int fd; |
| |
| opt = getopt32(argc, argv, "fiwb:", &bind_address); |
| if (optind < argc) |
| bogouser = argv[optind]; |
| |
| /* Daemonize if no -f and no -i and no -w */ |
| bb_sanitize_server_stdio(!(opt & OPT_fiw)); |
| /* Where to log in inetd modes? "Classic" inetd |
| * probably has its stderr /dev/null'ed (we need log to syslog?), |
| * but daemontools-like utilities usually expect that children |
| * log to stderr. I like daemontools more. Go their way. |
| * (Or maybe we need yet another option "log to syslog") */ |
| if (!(opt & OPT_fiw) /* || (opt & OPT_syslog) */) { |
| openlog(applet_name, 0, LOG_DAEMON); |
| logmode = LOGMODE_SYSLOG; |
| } |
| |
| if (opt & OPT_inetd) { |
| inetd_mode(); |
| return 0; |
| } |
| |
| /* Ignore closed connections when writing */ |
| signal(SIGPIPE, SIG_IGN); |
| |
| fd = 0; |
| if (!(opt & OPT_inetdwait)) { |
| fd = create_and_bind_stream_or_die(bind_address, |
| bb_lookup_port("identd", "tcp", 113)); |
| xlisten(fd, 5); |
| } |
| |
| isrv_run(fd, new_peer, do_rd, /*do_wr:*/ NULL, do_timeout, |
| TIMEOUT, (opt & OPT_inetdwait) ? TIMEOUT : 0); |
| return 0; |
| } |