source: branches/3.2/mindi-busybox/networking/isrv_identd.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 3.8 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Fake identd server.
4 *
5 * Copyright (C) 2007 Denys Vlasenko
6 *
7 * Licensed under GPLv2, see file LICENSE in this source tree.
8 */
9
10//usage:#define fakeidentd_trivial_usage
11//usage:       "[-fiw] [-b ADDR] [STRING]"
12//usage:#define fakeidentd_full_usage "\n\n"
13//usage:       "Provide fake ident (auth) service\n"
14//usage:     "\n    -f  Run in foreground"
15//usage:     "\n    -i  Inetd mode"
16//usage:     "\n    -w  Inetd 'wait' mode"
17//usage:     "\n    -b ADDR Bind to specified address"
18//usage:     "\n    STRING  Ident answer string (default: nobody)"
19
20#include "libbb.h"
21#include <syslog.h>
22#include "isrv.h"
23
24enum { TIMEOUT = 20 };
25
26typedef struct identd_buf_t {
27    int pos;
28    int fd_flag;
29    char buf[64 - 2*sizeof(int)];
30} identd_buf_t;
31
32#define bogouser bb_common_bufsiz1
33
34static int new_peer(isrv_state_t *state, int fd)
35{
36    int peer;
37    identd_buf_t *buf = xzalloc(sizeof(*buf));
38
39    peer = isrv_register_peer(state, buf);
40    if (peer < 0)
41        return 0; /* failure */
42    if (isrv_register_fd(state, peer, fd) < 0)
43        return peer; /* failure, unregister peer */
44
45    buf->fd_flag = fcntl(fd, F_GETFL) | O_NONBLOCK;
46    isrv_want_rd(state, fd);
47    return 0;
48}
49
50static int do_rd(int fd, void **paramp)
51{
52    identd_buf_t *buf = *paramp;
53    char *cur, *p;
54    int retval = 0; /* session is ok (so far) */
55    int sz;
56
57    cur = buf->buf + buf->pos;
58
59    if (buf->fd_flag & O_NONBLOCK)
60        fcntl(fd, F_SETFL, buf->fd_flag);
61    sz = safe_read(fd, cur, sizeof(buf->buf) - buf->pos);
62
63    if (sz < 0) {
64        if (errno != EAGAIN)
65            goto term; /* terminate this session if !EAGAIN */
66        goto ok;
67    }
68
69    buf->pos += sz;
70    buf->buf[buf->pos] = '\0';
71    p = strpbrk(cur, "\r\n");
72    if (p)
73        *p = '\0';
74    if (!p && sz && buf->pos <= (int)sizeof(buf->buf))
75        goto ok;
76    /* Terminate session. If we are in server mode, then
77     * fd is still in nonblocking mode - we never block here */
78    if (fd == 0) fd++; /* inetd mode? then write to fd 1 */
79    fdprintf(fd, "%s : USERID : UNIX : %s\r\n", buf->buf, bogouser);
80 term:
81    free(buf);
82    retval = 1; /* terminate */
83 ok:
84    if (buf->fd_flag & O_NONBLOCK)
85        fcntl(fd, F_SETFL, buf->fd_flag & ~O_NONBLOCK);
86    return retval;
87}
88
89static int do_timeout(void **paramp UNUSED_PARAM)
90{
91    return 1; /* terminate session */
92}
93
94static void inetd_mode(void)
95{
96    identd_buf_t *buf = xzalloc(sizeof(*buf));
97    /* buf->pos = 0; - xzalloc did it */
98    /* We do NOT want nonblocking I/O here! */
99    /* buf->fd_flag = 0; - xzalloc did it */
100    do
101        alarm(TIMEOUT);
102    while (do_rd(0, (void*)&buf) == 0);
103}
104
105int fakeidentd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
106int fakeidentd_main(int argc UNUSED_PARAM, char **argv)
107{
108    enum {
109        OPT_foreground = 0x1,
110        OPT_inetd      = 0x2,
111        OPT_inetdwait  = 0x4,
112        OPT_fiw        = 0x7,
113        OPT_bindaddr   = 0x8,
114    };
115
116    const char *bind_address = NULL;
117    unsigned opt;
118    int fd;
119
120    opt = getopt32(argv, "fiwb:", &bind_address);
121    strcpy(bogouser, "nobody");
122    if (argv[optind])
123        strncpy(bogouser, argv[optind], sizeof(bogouser));
124
125    /* Daemonize if no -f and no -i and no -w */
126    if (!(opt & OPT_fiw))
127        bb_daemonize_or_rexec(0, argv);
128
129    /* Where to log in inetd modes? "Classic" inetd
130     * probably has its stderr /dev/null'ed (we need log to syslog?),
131     * but daemontools-like utilities usually expect that children
132     * log to stderr. I like daemontools more. Go their way.
133     * (Or maybe we need yet another option "log to syslog") */
134    if (!(opt & OPT_fiw) /* || (opt & OPT_syslog) */) {
135        openlog(applet_name, LOG_PID, LOG_DAEMON);
136        logmode = LOGMODE_SYSLOG;
137    }
138
139    if (opt & OPT_inetd) {
140        inetd_mode();
141        return 0;
142    }
143
144    /* Ignore closed connections when writing */
145    signal(SIGPIPE, SIG_IGN);
146
147    fd = 0;
148    if (!(opt & OPT_inetdwait)) {
149        fd = create_and_bind_stream_or_die(bind_address,
150                bb_lookup_port("identd", "tcp", 113));
151        xlisten(fd, 5);
152    }
153
154    isrv_run(fd, new_peer, do_rd, /*do_wr:*/ NULL, do_timeout,
155            TIMEOUT, (opt & OPT_inetdwait) ? TIMEOUT : 0);
156    return 0;
157}
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