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authorDenys Vlasenko <vda.linux@googlemail.com>2010-10-29 00:12:22 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2010-10-29 00:12:22 (GMT)
commit036dbb9d9ab239bbd7eecad8580876c9c3e57dc5 (patch)
treec8193d9c5da63a1a58eb34eba1bade3629ecd778
parent6b3f0b0dab46d910f7797dfc8d8554546dd33fa2 (diff)
downloadbusybox-036dbb9d9ab239bbd7eecad8580876c9c3e57dc5.tar.gz
busybox-036dbb9d9ab239bbd7eecad8580876c9c3e57dc5.tar.bz2
telnet: convert CR NUL -> CR on input. Closes bug 2569
function old new delta telnet_main 1558 1594 +36 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/telnet.c132
1 files changed, 63 insertions, 69 deletions
diff --git a/networking/telnet.c b/networking/telnet.c
index 12d1970..0cf28f6 100644
--- a/networking/telnet.c
+++ b/networking/telnet.c
@@ -42,11 +42,13 @@ enum {
UF_ECHO = 0x01,
UF_SGA = 0x02,
- TS_0 = 1,
+ TS_NORMAL = 0,
+ TS_COPY = 1,
TS_IAC = 2,
TS_OPT = 3,
TS_SUB1 = 4,
TS_SUB2 = 5,
+ TS_CR = 6,
};
typedef unsigned char byte;
@@ -83,13 +85,13 @@ struct globals {
}; \
} while (0)
-/* Function prototypes */
+
static void rawmode(void);
static void cookmode(void);
static void do_linemode(void);
static void will_charmode(void);
static void telopt(byte c);
-static int subneg(byte c);
+static void subneg(byte c);
static void iac_flush(void)
{
@@ -170,24 +172,24 @@ static void handle_net_output(int len)
* So I implemented it. It's really useful for me. I hope that
* other people will find it interesting too.
*/
-
- int i, j;
+ byte outbuf[2 * DATABUFSIZE];
byte *p = (byte*)G.buf;
- byte outbuf[4*DATABUFSIZE];
+ int j = 0;
- for (i = len, j = 0; i > 0; i--, p++) {
- if (*p == 0x1d) {
+ for (; len > 0; len--, p++) {
+ byte c = *p;
+ if (c == 0x1d) {
con_escape();
return;
}
- outbuf[j++] = *p;
- if (*p == 0xff)
- outbuf[j++] = 0xff;
- else if (*p == 0x0d)
- outbuf[j++] = 0x00;
+ outbuf[j++] = c;
+ if (c == IAC)
+ outbuf[j++] = c; /* IAC -> IAC IAC */
+ else if (c == '\r')
+ outbuf[j++] = '\0'; /* CR -> CR NUL */
}
if (j > 0)
- write(netfd, outbuf, j);
+ full_write(netfd, outbuf, j);
}
static void handle_net_input(int len)
@@ -198,25 +200,44 @@ static void handle_net_input(int len)
for (i = 0; i < len; i++) {
byte c = G.buf[i];
- if (G.telstate == 0) { /* most of the time state == 0 */
+ if (G.telstate == TS_NORMAL) { /* most typical state */
if (c == IAC) {
cstart = i;
G.telstate = TS_IAC;
}
+ else if (c == '\r') {
+ cstart = i + 1;
+ G.telstate = TS_CR;
+ }
+ /* No IACs were seen so far, no need to copy
+ * bytes within G.buf: */
continue;
}
+
switch (G.telstate) {
- case TS_0:
+ case TS_CR:
+ /* Prev char was CR. If cur one is NUL, ignore it.
+ * See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
+ */
+ G.telstate = TS_COPY;
+ if (c == '\0')
+ break;
+ /* else: fall through - need to handle CR IAC ... properly */
+
+ case TS_COPY: /* Prev char was ordinary */
+ /* Similar to NORMAL, but in TS_COPY we need to copy bytes */
if (c == IAC)
G.telstate = TS_IAC;
else
G.buf[cstart++] = c;
+ if (c == '\r')
+ G.telstate = TS_CR;
break;
- case TS_IAC:
- if (c == IAC) { /* IAC IAC -> 0xFF */
+ case TS_IAC: /* Prev char was IAC */
+ if (c == IAC) { /* IAC IAC -> one IAC */
G.buf[cstart++] = c;
- G.telstate = TS_0;
+ G.telstate = TS_COPY;
break;
}
/* else */
@@ -228,34 +249,38 @@ static void handle_net_input(int len)
case DONT:
case WILL:
case WONT:
- G.telwish = c;
+ G.telwish = c;
G.telstate = TS_OPT;
break;
+ /* DATA MARK must be added later */
default:
- G.telstate = TS_0; /* DATA MARK must be added later */
+ G.telstate = TS_COPY;
}
break;
- case TS_OPT: /* WILL, WONT, DO, DONT */
+
+ case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
telopt(c);
- G.telstate = TS_0;
+ G.telstate = TS_COPY;
break;
+
case TS_SUB1: /* Subnegotiation */
case TS_SUB2: /* Subnegotiation */
- if (subneg(c))
- G.telstate = TS_0;
+ subneg(c); /* can change G.telstate */
break;
}
}
- if (G.telstate) {
+
+ if (G.telstate != TS_NORMAL) {
+ /* We had some IACs, or CR */
if (G.iaclen)
iac_flush();
- if (G.telstate == TS_0)
- G.telstate = 0;
+ if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
+ G.telstate = TS_NORMAL;
len = cstart;
}
if (len)
- write(STDOUT_FILENO, G.buf, len);
+ full_write(STDOUT_FILENO, G.buf, len);
}
static void put_iac(int c)
@@ -495,7 +520,7 @@ static void telopt(byte c)
}
/* subnegotiation -- ignore all (except TTYPE,NAWS) */
-static int subneg(byte c)
+static void subneg(byte c)
{
switch (G.telstate) {
case TS_SUB1:
@@ -513,12 +538,13 @@ static int subneg(byte c)
#endif
break;
case TS_SUB2:
- if (c == SE)
- return TRUE;
+ if (c == SE) {
+ G.telstate = TS_COPY;
+ return;
+ }
G.telstate = TS_SUB1;
- /* break; */
+ break;
}
- return FALSE;
}
static void rawmode(void)
@@ -533,21 +559,13 @@ static void cookmode(void)
tcsetattr(0, TCSADRAIN, &G.termios_def);
}
-/* poll gives smaller (-70 bytes) code */
-#define USE_POLL 1
-
int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int telnet_main(int argc UNUSED_PARAM, char **argv)
{
char *host;
int port;
int len;
-#ifdef USE_POLL
struct pollfd ufds[2];
-#else
- fd_set readfds;
- int maxfd;
-#endif
INIT_G();
@@ -585,25 +603,11 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)
signal(SIGINT, record_signo);
-#ifdef USE_POLL
ufds[0].fd = 0; ufds[1].fd = netfd;
ufds[0].events = ufds[1].events = POLLIN;
-#else
- FD_ZERO(&readfds);
- FD_SET(STDIN_FILENO, &readfds);
- FD_SET(netfd, &readfds);
- maxfd = netfd + 1;
-#endif
while (1) {
-#ifndef USE_POLL
- fd_set rfds = readfds;
-
- switch (select(maxfd, &rfds, NULL, NULL, NULL))
-#else
- switch (poll(ufds, 2, -1))
-#endif
- {
+ switch (poll(ufds, 2, -1)) {
case 0:
/* timeout */
case -1:
@@ -615,12 +619,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)
break;
default:
-#ifdef USE_POLL
- if (ufds[0].revents)
-#else
- if (FD_ISSET(STDIN_FILENO, &rfds))
-#endif
- {
+ if (ufds[0].revents) {
len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
if (len <= 0)
doexit(EXIT_SUCCESS);
@@ -628,12 +627,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)
handle_net_output(len);
}
-#ifdef USE_POLL
- if (ufds[1].revents)
-#else
- if (FD_ISSET(netfd, &rfds))
-#endif
- {
+ if (ufds[1].revents) {
len = safe_read(netfd, G.buf, DATABUFSIZE);
if (len <= 0) {
full_write1_str("Connection closed by foreign host\r\n");