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telnetd: add -w ("inetd wait") option. Can be configured off.

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gcc fils to fully optimize it out when it's off:

function                                             old     new   delta
telnetd_main                                        1527    1548     +21
packed_usage                                       26596   26587      -9

but nevertheless it's a useful (and so far single) example
how to write "inetd wait" tcp service.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2009-09-04 02:21:13 +02:00
parent cfc216345e
commit ed1667e8ee
3 changed files with 69 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
networking/telnetd.c
View File

@@ -211,8 +211,10 @@ static size_t iac_safe_write(int fd, const char *buf, size_t count)
enum {
OPT_WATCHCHILD = (1 << 2), /* -K */
OPT_INETD = (1 << 3) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -i */
OPT_PORT = (1 << 4) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -p */
OPT_PORT = (1 << 4) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -p PORT */
OPT_FOREGROUND = (1 << 6) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -F */
OPT_SYSLOG = (1 << 7) * ENABLE_FEATURE_TELNETD_INETD_WAIT, /* -S */
OPT_WAIT = (1 << 8) * ENABLE_FEATURE_TELNETD_INETD_WAIT, /* -w SEC */
};
static struct tsession *
@@ -438,24 +440,29 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
struct tsession *ts;
#if ENABLE_FEATURE_TELNETD_STANDALONE
#define IS_INETD (opt & OPT_INETD)
int master_fd = master_fd; /* be happy, gcc */
unsigned portnbr = 23;
int master_fd = master_fd; /* for compiler */
int sec_linger = sec_linger;
char *opt_bindaddr = NULL;
char *opt_portnbr;
#else
enum {
IS_INETD = 1,
master_fd = -1,
portnbr = 23,
};
#endif
INIT_G();
/* -w NUM, and implies -F. -w and -i don't mix */
IF_FEATURE_TELNETD_INETD_WAIT(opt_complementary = "wF:w+:i--w:w--i";)
/* Even if !STANDALONE, we accept (and ignore) -i, thus people
* don't need to guess whether it's ok to pass -i to us */
opt = getopt32(argv, "f:l:Ki" IF_FEATURE_TELNETD_STANDALONE("p:b:F"),
opt = getopt32(argv, "f:l:Ki"
IF_FEATURE_TELNETD_STANDALONE("p:b:F")
IF_FEATURE_TELNETD_INETD_WAIT("Sw:"),
&G.issuefile, &G.loginpath
IF_FEATURE_TELNETD_STANDALONE(, &opt_portnbr, &opt_bindaddr));
IF_FEATURE_TELNETD_STANDALONE(, &opt_portnbr, &opt_bindaddr)
IF_FEATURE_TELNETD_INETD_WAIT(, &sec_linger)
);
if (!IS_INETD /*&& !re_execed*/) {
/* inform that we start in standalone mode?
* May be useful when people forget to give -i */
@@ -467,32 +474,30 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
}
}
/* Redirect log to syslog early, if needed */
if (IS_INETD || !(opt & OPT_FOREGROUND)) {
if (IS_INETD || (opt & OPT_SYSLOG) || !(opt & OPT_FOREGROUND)) {
openlog(applet_name, LOG_PID, LOG_DAEMON);
logmode = LOGMODE_SYSLOG;
}
IF_FEATURE_TELNETD_STANDALONE(
if (opt & OPT_PORT)
portnbr = xatou16(opt_portnbr);
);
/* Used to check access(G.loginpath, X_OK) here. Pointless.
* exec will do this for us for free later. */
#if ENABLE_FEATURE_TELNETD_STANDALONE
if (IS_INETD) {
G.sessions = make_new_session(0);
if (!G.sessions) /* pty opening or vfork problem, exit */
return 1; /* make_new_session prints error message */
return 1; /* make_new_session printed error message */
} else {
master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr);
xlisten(master_fd, 1);
master_fd = 0;
if (!(opt & OPT_WAIT)) {
unsigned portnbr = 23;
if (opt & OPT_PORT)
portnbr = xatou16(opt_portnbr);
master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr);
xlisten(master_fd, 1);
}
close_on_exec_on(master_fd);
}
#else
G.sessions = make_new_session();
if (!G.sessions) /* pty opening or vfork problem, exit */
return 1; /* make_new_session prints error message */
return 1; /* make_new_session printed error message */
#endif
/* We don't want to die if just one session is broken */
@@ -556,7 +561,18 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
G.maxfd = master_fd;
}
count = select(G.maxfd + 1, &rdfdset, &wrfdset, NULL, NULL);
{
struct timeval tv;
struct timeval *tv_ptr = NULL;
if ((opt & OPT_WAIT) && !G.sessions) {
tv.tv_sec = sec_linger;
tv.tv_usec = 0;
tv_ptr = &tv;
}
count = select(G.maxfd + 1, &rdfdset, &wrfdset, NULL, tv_ptr);
}
if (count == 0) /* "telnetd -w SEC" timed out */
return 0;
if (count < 0)
goto again; /* EINTR or ENOMEM */