From 9f2f808b0dd531840b906e6dd09550a626c32bf1 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Tue, 11 Nov 2008 02:56:39 +0000 Subject: [PATCH] telnetd: correctly output 0xff char. ~100 bytes. telnet: fix some atrocious names and style. no code changes --- networking/telnet.c | 232 ++++++++++++++++++++++--------------------- networking/telnetd.c | 58 +++++++++-- 2 files changed, 168 insertions(+), 122 deletions(-) diff --git a/networking/telnet.c b/networking/telnet.c index 5d7ecef3b..ba6f2fb83 100644 --- a/networking/telnet.c +++ b/networking/telnet.c @@ -93,7 +93,7 @@ static void will_charmode(void); static void telopt(byte c); static int subneg(byte c); -static void iacflush(void) +static void iac_flush(void) { write(netfd, G.iacbuf, G.iaclen); G.iaclen = 0; @@ -108,11 +108,11 @@ static void doexit(int ev) exit(ev); } -static void conescape(void) +static void con_escape(void) { char b; - if (bb_got_signal) /* came from line mode... go raw */ + if (bb_got_signal) /* came from line mode... go raw */ rawmode(); write_str(1, "\r\nConsole escape. Commands are:\r\n\n" @@ -128,13 +128,13 @@ static void conescape(void) case 'l': if (!bb_got_signal) { do_linemode(); - goto rrturn; + goto ret; } break; case 'c': if (bb_got_signal) { will_charmode(); - goto rrturn; + goto ret; } break; case 'z': @@ -150,13 +150,12 @@ static void conescape(void) if (bb_got_signal) cookmode(); - - rrturn: + ret: bb_got_signal = 0; } -static void handlenetoutput(int len) +static void handle_net_output(int len) { /* here we could do smart tricks how to handle 0xFF:s in output * stream like writing twice every sequence of FF:s (thus doing @@ -169,19 +168,19 @@ static void handlenetoutput(int len) * first - I cannot use programs like sz/rz * second - the 0x0D is sent as one character and if the next * char is 0x0A then it's eaten by a server side. - * third - whay doy you have to make 'many write()s'? + * third - why do you have to make 'many write()s'? * I don't understand. - * So I implemented it. It's realy useful for me. I hope that - * others people will find it interesting too. + * So I implemented it. It's really useful for me. I hope that + * other people will find it interesting too. */ int i, j; - byte * p = (byte*)G.buf; + byte *p = (byte*)G.buf; byte outbuf[4*DATABUFSIZE]; for (i = len, j = 0; i > 0; i--, p++) { if (*p == 0x1d) { - conescape(); + con_escape(); return; } outbuf[j++] = *p; @@ -194,7 +193,7 @@ static void handlenetoutput(int len) write(netfd, outbuf, j); } -static void handlenetinput(int len) +static void handle_net_input(int len) { int i; int cstart = 0; @@ -207,51 +206,54 @@ static void handlenetinput(int len) cstart = i; G.telstate = TS_IAC; } - } else - switch (G.telstate) { - case TS_0: - if (c == IAC) - G.telstate = TS_IAC; - else - G.buf[cstart++] = c; - break; + continue; + } + switch (G.telstate) { + case TS_0: + if (c == IAC) + G.telstate = TS_IAC; + else + G.buf[cstart++] = c; + break; - case TS_IAC: - if (c == IAC) { /* IAC IAC -> 0xFF */ - G.buf[cstart++] = c; - G.telstate = TS_0; - break; - } - /* else */ - switch (c) { - case SB: - G.telstate = TS_SUB1; - break; - case DO: - case DONT: - case WILL: - case WONT: - G.telwish = c; - G.telstate = TS_OPT; - break; - default: - G.telstate = TS_0; /* DATA MARK must be added later */ - } - break; - case TS_OPT: /* WILL, WONT, DO, DONT */ - telopt(c); + case TS_IAC: + if (c == IAC) { /* IAC IAC -> 0xFF */ + G.buf[cstart++] = c; G.telstate = TS_0; break; - case TS_SUB1: /* Subnegotiation */ - case TS_SUB2: /* Subnegotiation */ - if (subneg(c)) - G.telstate = TS_0; + } + /* else */ + switch (c) { + case SB: + G.telstate = TS_SUB1; + break; + case DO: + case DONT: + case WILL: + case WONT: + G.telwish = c; + G.telstate = TS_OPT; break; + default: + G.telstate = TS_0; /* DATA MARK must be added later */ } + break; + case TS_OPT: /* WILL, WONT, DO, DONT */ + telopt(c); + G.telstate = TS_0; + break; + case TS_SUB1: /* Subnegotiation */ + case TS_SUB2: /* Subnegotiation */ + if (subneg(c)) + G.telstate = TS_0; + break; + } } if (G.telstate) { - if (G.iaclen) iacflush(); - if (G.telstate == TS_0) G.telstate = 0; + if (G.iaclen) + iac_flush(); + if (G.telstate == TS_0) + G.telstate = 0; len = cstart; } @@ -259,87 +261,87 @@ static void handlenetinput(int len) write(STDOUT_FILENO, G.buf, len); } -static void putiac(int c) +static void put_iac(int c) { G.iacbuf[G.iaclen++] = c; } -static void putiac2(byte wwdd, byte c) +static void put_iac2(byte wwdd, byte c) { if (G.iaclen + 3 > IACBUFSIZE) - iacflush(); + iac_flush(); - putiac(IAC); - putiac(wwdd); - putiac(c); + put_iac(IAC); + put_iac(wwdd); + put_iac(c); } #if ENABLE_FEATURE_TELNET_TTYPE -static void putiac_subopt(byte c, char *str) +static void put_iac_subopt(byte c, char *str) { - int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 ) + int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 ) if (G.iaclen + len > IACBUFSIZE) - iacflush(); + iac_flush(); - putiac(IAC); - putiac(SB); - putiac(c); - putiac(0); + put_iac(IAC); + put_iac(SB); + put_iac(c); + put_iac(0); while (*str) - putiac(*str++); + put_iac(*str++); - putiac(IAC); - putiac(SE); + put_iac(IAC); + put_iac(SE); } #endif #if ENABLE_FEATURE_TELNET_AUTOLOGIN -static void putiac_subopt_autologin(void) +static void put_iac_subopt_autologin(void) { int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2) const char *user = "USER"; if (G.iaclen + len > IACBUFSIZE) - iacflush(); + iac_flush(); - putiac(IAC); - putiac(SB); - putiac(TELOPT_NEW_ENVIRON); - putiac(TELQUAL_IS); - putiac(NEW_ENV_VAR); + put_iac(IAC); + put_iac(SB); + put_iac(TELOPT_NEW_ENVIRON); + put_iac(TELQUAL_IS); + put_iac(NEW_ENV_VAR); while (*user) - putiac(*user++); + put_iac(*user++); - putiac(NEW_ENV_VALUE); + put_iac(NEW_ENV_VALUE); while (*G.autologin) - putiac(*G.autologin++); + put_iac(*G.autologin++); - putiac(IAC); - putiac(SE); + put_iac(IAC); + put_iac(SE); } #endif #if ENABLE_FEATURE_AUTOWIDTH -static void putiac_naws(byte c, int x, int y) +static void put_iac_naws(byte c, int x, int y) { if (G.iaclen + 9 > IACBUFSIZE) - iacflush(); + iac_flush(); - putiac(IAC); - putiac(SB); - putiac(c); + put_iac(IAC); + put_iac(SB); + put_iac(c); - putiac((x >> 8) & 0xff); - putiac(x & 0xff); - putiac((y >> 8) & 0xff); - putiac(y & 0xff); + put_iac((x >> 8) & 0xff); + put_iac(x & 0xff); + put_iac((y >> 8) & 0xff); + put_iac(y & 0xff); - putiac(IAC); - putiac(SE); + put_iac(IAC); + put_iac(SE); } #endif @@ -368,9 +370,9 @@ static void will_charmode(void) G.telflags |= (UF_ECHO | UF_SGA); setConMode(); - putiac2(DO, TELOPT_ECHO); - putiac2(DO, TELOPT_SGA); - iacflush(); + put_iac2(DO, TELOPT_ECHO); + put_iac2(DO, TELOPT_SGA); + iac_flush(); } static void do_linemode(void) @@ -379,24 +381,24 @@ static void do_linemode(void) G.telflags &= ~(UF_ECHO | UF_SGA); setConMode(); - putiac2(DONT, TELOPT_ECHO); - putiac2(DONT, TELOPT_SGA); - iacflush(); + put_iac2(DONT, TELOPT_ECHO); + put_iac2(DONT, TELOPT_SGA); + iac_flush(); } static void to_notsup(char c) { if (G.telwish == WILL) - putiac2(DONT, c); + put_iac2(DONT, c); else if (G.telwish == DO) - putiac2(WONT, c); + put_iac2(WONT, c); } static void to_echo(void) { /* if server requests ECHO, don't agree */ if (G.telwish == DO) { - putiac2(WONT, TELOPT_ECHO); + put_iac2(WONT, TELOPT_ECHO); return; } if (G.telwish == DONT) @@ -412,9 +414,9 @@ static void to_echo(void) G.telflags ^= UF_ECHO; if (G.telflags & UF_ECHO) - putiac2(DO, TELOPT_ECHO); + put_iac2(DO, TELOPT_ECHO); else - putiac2(DONT, TELOPT_ECHO); + put_iac2(DONT, TELOPT_ECHO); setConMode(); write_str(1, "\r\n"); /* sudden modec */ @@ -432,9 +434,9 @@ static void to_sga(void) G.telflags ^= UF_SGA; /* toggle */ if (G.telflags & UF_SGA) - putiac2(DO, TELOPT_SGA); + put_iac2(DO, TELOPT_SGA); else - putiac2(DONT, TELOPT_SGA); + put_iac2(DONT, TELOPT_SGA); } #if ENABLE_FEATURE_TELNET_TTYPE @@ -443,9 +445,9 @@ static void to_ttype(void) /* Tell server we will (or won't) do TTYPE */ if (G.ttype) - putiac2(WILL, TELOPT_TTYPE); + put_iac2(WILL, TELOPT_TTYPE); else - putiac2(WONT, TELOPT_TTYPE); + put_iac2(WONT, TELOPT_TTYPE); } #endif @@ -455,9 +457,9 @@ static void to_new_environ(void) /* Tell server we will (or will not) do AUTOLOGIN */ if (G.autologin) - putiac2(WILL, TELOPT_NEW_ENVIRON); + put_iac2(WILL, TELOPT_NEW_ENVIRON); else - putiac2(WONT, TELOPT_NEW_ENVIRON); + put_iac2(WONT, TELOPT_NEW_ENVIRON); } #endif @@ -465,7 +467,7 @@ static void to_new_environ(void) static void to_naws(void) { /* Tell server we will do NAWS */ - putiac2(WILL, TELOPT_NAWS); + put_iac2(WILL, TELOPT_NAWS); } #endif @@ -487,7 +489,7 @@ static void telopt(byte c) #if ENABLE_FEATURE_AUTOWIDTH case TELOPT_NAWS: to_naws(); - putiac_naws(c, G.win_width, G.win_height); + put_iac_naws(c, G.win_width, G.win_height); break; #endif default: @@ -506,12 +508,12 @@ static int subneg(byte c) #if ENABLE_FEATURE_TELNET_TTYPE else if (c == TELOPT_TTYPE) - putiac_subopt(TELOPT_TTYPE, G.ttype); + put_iac_subopt(TELOPT_TTYPE, G.ttype); #endif #if ENABLE_FEATURE_TELNET_AUTOLOGIN else if (c == TELOPT_NEW_ENVIRON) - putiac_subopt_autologin(); + put_iac_subopt_autologin(); #endif break; case TS_SUB2: @@ -611,7 +613,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv) case -1: /* error, ignore and/or log something, bay go to loop */ if (bb_got_signal) - conescape(); + con_escape(); else sleep(1); break; @@ -627,7 +629,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv) if (len <= 0) doexit(EXIT_SUCCESS); TRACE(0, ("Read con: %d\n", len)); - handlenetoutput(len); + handle_net_output(len); } #ifdef USE_POLL @@ -642,7 +644,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv) doexit(EXIT_FAILURE); } TRACE(0, ("Read netfd (%d): %d\n", netfd, len)); - handlenetinput(len); + handle_net_input(len); } } } /* while (1) */ diff --git a/networking/telnetd.c b/networking/telnetd.c index 46dfb318f..f04b32f9e 100644 --- a/networking/telnetd.c +++ b/networking/telnetd.c @@ -74,9 +74,6 @@ static const char *issuefile = "/etc/issue.net"; past (bf + len) then that IAC will be left unprocessed and *processed will be less than len. - FIXME - if we mean to send 0xFF to the terminal then it will be escaped, - what is the escape character? We aren't handling that situation here. - CR-LF ->'s CR mapping is also done here, for convenience. NB: may fail to remove iacs which wrap around buffer! @@ -159,6 +156,47 @@ remove_iacs(struct tsession *ts, int *pnum_totty) return memmove(ptr - num_totty, ptr0, num_totty); } +/* + * Converting single 0xff into double on output + */ +static size_t iac_safe_write(int fd, const char *buf, size_t count) +{ + const char *oxff; + size_t wr, rc, total; + + total = 0; + while (1) { + if (count == 0) + return total; + if (*buf == (char)0xff) { + rc = safe_write(fd, "\xff\xff", 2); + if (rc != 2) + break; + buf++; + total++; + count--; + continue; + } + /* count != 0, *buf != 0xff */ + oxff = memchr(buf, 0xff, count); + wr = count; + if (oxff) + wr = oxff - buf; + rc = safe_write(fd, buf, wr); + if (rc != wr) + break; + buf += rc; + total += rc; + count -= rc; + } + /* here: rc - result of last short write */ + if ((ssize_t)rc < 0) { /* error? */ + if (total == 0) + return rc; + rc = 0; + } + return total + rc; +} static struct tsession * make_new_session( @@ -212,9 +250,15 @@ make_new_session( IAC, WILL, TELOPT_ECHO, IAC, WILL, TELOPT_SGA }; - memcpy(TS_BUF2, iacs_to_send, sizeof(iacs_to_send)); - ts->rdidx2 = sizeof(iacs_to_send); - ts->size2 = sizeof(iacs_to_send); + /* This confuses iac_safe_write(), it will try to duplicate + * each IAC... */ + //memcpy(TS_BUF2, iacs_to_send, sizeof(iacs_to_send)); + //ts->rdidx2 = sizeof(iacs_to_send); + //ts->size2 = sizeof(iacs_to_send); + /* So just stuff it into TCP buffer! */ + safe_write(sock, iacs_to_send, sizeof(iacs_to_send)); + /*ts->rdidx2 = 0; - xzalloc did it! */ + /*ts->size2 = 0;*/ } fflush(NULL); /* flush all streams */ @@ -538,7 +582,7 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv) if (/*ts->size2 &&*/ FD_ISSET(ts->sockfd_write, &wrfdset)) { /* Write to socket from buffer 2. */ count = MIN(BUFSIZE - ts->wridx2, ts->size2); - count = safe_write(ts->sockfd_write, TS_BUF2 + ts->wridx2, count); + count = iac_safe_write(ts->sockfd_write, (void*)(TS_BUF2 + ts->wridx2), count); if (count < 0) { if (errno == EAGAIN) goto skip2; -- 2.25.1