Contents of /trunk/mkinitrd-magellan/busybox/networking/telnetd.ctrlSQ.patch
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Sun May 30 11:32:42 2010 UTC (14 years, 3 months ago) by niro
File size: 6625 byte(s)
Sun May 30 11:32:42 2010 UTC (14 years, 3 months ago) by niro
File size: 6625 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | From: "Doug Graham" <dgraham@nortel.com> |
2 | Date: 2009-01-22 07:20 |
3 | |
4 | Hello, |
5 | |
6 | Busybox's telnetd does not disable local (client-side) flow control |
7 | properly. It does not put the pty into packet mode and then notify the |
8 | client whenever flow control is disabled by an application running under |
9 | its control. The result is that ^S/^Q are not passed through to the |
10 | application, which is painful when the application is an emacs variant. |
11 | |
12 | I suppose that support for this might be considered bloat, but the |
13 | included patch only adds about 200 bytes of text to x86 busybox and 300 |
14 | bytes to mipsel busybox. Please consider applying. |
15 | |
16 | ============================= |
17 | |
18 | NB: the patch doesn't work as-is because we now have iac_safe_write() |
19 | which quotes IACs on output. |
20 | |
21 | ============================= |
22 | Docs: |
23 | |
24 | The following ioctl(2) calls apply only to pseudo terminals: |
25 | |
26 | TIOCSTOP Stops output to a terminal (e.g. like typing ^S). Takes no parameter. |
27 | |
28 | TIOCSTART Restarts output (stopped by TIOCSTOP or by typing ^S). Takes no parameter. |
29 | |
30 | TIOCPKT Enable/disable packet mode. When applied to the master side of a pseudo terminal, each |
31 | subsequent read(2) from the terminal will return data written on the slave part of the pseudo terminal preceded by a |
32 | zero byte (symbolically defined as TIOCPKT_DATA), or a single byte reflecting control status information. |
33 | In the latter case, the byte is an inclusive-or of zero or more of the bits: |
34 | |
35 | TIOCPKT_FLUSHREAD whenever the read queue for the terminal is flushed. |
36 | TIOCPKT_FLUSHWRITE whenever the write queue for the terminal is flushed. |
37 | TIOCPKT_STOP whenever output to the terminal is stopped a la ^S. |
38 | TIOCPKT_START whenever output to the terminal is restarted. |
39 | TIOCPKT_DOSTOP whenever t_stopc is ^S and t_startc is ^Q. |
40 | TIOCPKT_NOSTOP whenever the start and stop characters are not ^S/^Q. |
41 | |
42 | While this mode is in use, the presence of control status information to be read from the master side may be detected |
43 | by a select(2) for exceptional conditions. |
44 | |
45 | This mode is used by rlogin(1) and rlogind(8) to implement a remote-echoed, locally ^S/^Q flow-controlled remote login |
46 | with proper back-flushing of output; it can be used by other similar programs. |
47 | |
48 | TIOCUCNTL Enable/disable a mode that allows a small number of simple user ioctl(2) commands to be passed through |
49 | the pseudo-terminal, using a protocol similar to that of TIOCPKT. The TIOCUCNTL and TIOCPKT modes are mutually |
50 | exclusive. This mode is enabled from the master side of a pseudo terminal. Each subsequent read(2) from the master side |
51 | will return data written on the slave part of the pseudo terminal preceded by a zero byte, or a single byte reflecting a |
52 | user control operation on the slave side. A user control command consists of a special ioctl(2) operation with no data; |
53 | the command is given as UIOCCMD (n), where n is a number in the range 1-255. The operation value n will be received as |
54 | a single byte on the next read(2) from the master side. The ioctl(2) UIOCCMD (0) is a no-op that may be used to probe |
55 | for the existence of this facility. As with TIOCPKT mode, command operations may be detected with a select(2) for |
56 | exceptional conditions. |
57 | |
58 | --- busybox-1.13.2/networking/telnetd.c 2009/01/21 20:02:39 1.1 |
59 | +++ busybox-1.13.2/networking/telnetd.c 2009/01/22 00:35:28 |
60 | @@ -38,6 +38,9 @@ |
61 | int sockfd_read, sockfd_write, ptyfd; |
62 | int shell_pid; |
63 | |
64 | +#ifdef TIOCPKT |
65 | + int flowstate; |
66 | +#endif |
67 | /* two circular buffers */ |
68 | /*char *buf1, *buf2;*/ |
69 | /*#define TS_BUF1 ts->buf1*/ |
70 | @@ -170,6 +173,9 @@ |
71 | int fd, pid; |
72 | char tty_name[GETPTY_BUFSIZE]; |
73 | struct tsession *ts = xzalloc(sizeof(struct tsession) + BUFSIZE * 2); |
74 | +#ifdef TIOCPKT |
75 | + int on = 1; |
76 | +#endif |
77 | |
78 | /*ts->buf1 = (char *)(ts + 1);*/ |
79 | /*ts->buf2 = ts->buf1 + BUFSIZE;*/ |
80 | @@ -180,6 +186,10 @@ |
81 | maxfd = fd; |
82 | ts->ptyfd = fd; |
83 | ndelay_on(fd); |
84 | +#ifdef TIOCPKT |
85 | + ioctl(fd, TIOCPKT, &on); |
86 | + ts->flowstate = TIOCPKT_DOSTOP; |
87 | +#endif |
88 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
89 | ts->sockfd_read = sock; |
90 | /* SO_KEEPALIVE by popular demand */ |
91 | @@ -385,6 +395,16 @@ |
92 | portnbr = 23, |
93 | }; |
94 | #endif |
95 | +#ifdef TIOCPKT |
96 | + int control; |
97 | + static const char lflow_on[] = |
98 | + {IAC, SB, TELOPT_LFLOW, LFLOW_ON, IAC, SE}; |
99 | + static const char lflow_off[] = |
100 | + {IAC, SB, TELOPT_LFLOW, LFLOW_OFF, IAC, SE}; |
101 | +# define RESERVED sizeof(lflow_on) |
102 | +#else |
103 | +# define RESERVED 0 |
104 | +#endif |
105 | /* Even if !STANDALONE, we accept (and ignore) -i, thus people |
106 | * don't need to guess whether it's ok to pass -i to us */ |
107 | opt = getopt32(argv, "f:l:Ki" IF_FEATURE_TELNETD_STANDALONE("p:b:F"), |
108 | @@ -475,7 +495,7 @@ |
109 | FD_SET(ts->sockfd_read, &rdfdset); |
110 | if (ts->size2 > 0) /* can write to socket */ |
111 | FD_SET(ts->sockfd_write, &wrfdset); |
112 | - if (ts->size2 < BUFSIZE) /* can read from pty */ |
113 | + if (ts->size2 < (BUFSIZE - RESERVED)) /* can read from pty */ |
114 | FD_SET(ts->ptyfd, &rdfdset); |
115 | } |
116 | ts = next; |
117 | @@ -593,6 +613,52 @@ |
118 | goto skip4; |
119 | goto kill_session; |
120 | } |
121 | +#ifdef TIOCPKT |
122 | + control = TS_BUF2[ts->rdidx2]; |
123 | + if (--count > 0 && control == TIOCPKT_DATA) { |
124 | + /* |
125 | + * If we are in packet mode, and we have |
126 | + * just read a chunk of actual data from |
127 | + * the pty, then there is the TIOCPKT_DATA |
128 | + * byte (zero) that we have got to remove |
129 | + * somehow. If there were no chars in |
130 | + * TS_BUF2 before we did this read, then |
131 | + * we can optimize by just advancing wridx2. |
132 | + * Otherwise we have to copy the new data down |
133 | + * to close the gap (Could use readv() instead). |
134 | + */ |
135 | + if (ts->size2 == 0) |
136 | + ts->wridx2++; |
137 | + else { |
138 | + memmove(TS_BUF2 + ts->rdidx2, |
139 | + TS_BUF2 + ts->rdidx2 + 1, count); |
140 | + } |
141 | + } |
142 | + |
143 | + /* |
144 | + * If the flow control state changed, notify |
145 | + * the client. If "control" is not TIOCPKT_DATA, |
146 | + * then there are no data bytes to worry about. |
147 | + */ |
148 | + if ((control & (TIOCPKT_DOSTOP|TIOCPKT_NOSTOP)) != 0 |
149 | + && ts->flowstate != (control & TIOCPKT_DOSTOP)) { |
150 | + const char *p = ts->flowstate ? lflow_off : lflow_on; |
151 | + |
152 | + /* |
153 | + * We know we have enough free slots available |
154 | + * (see RESERVED) but they are not necessarily |
155 | + * contiguous; we may have to wrap. |
156 | + */ |
157 | + for (count = sizeof(lflow_on); count > 0; count--) { |
158 | + TS_BUF2[ts->rdidx2++] = *p++; |
159 | + if (ts->rdidx2 >= BUFSIZE) |
160 | + ts->rdidx2 = 0; |
161 | + ts->size2++; |
162 | + } |
163 | + |
164 | + ts->flowstate = control & TIOCPKT_DOSTOP; |
165 | + } |
166 | +#endif /* TIOCPKT */ |
167 | ts->size2 += count; |
168 | ts->rdidx2 += count; |
169 | if (ts->rdidx2 >= BUFSIZE) /* actually == BUFSIZE */ |
170 | |
171 | --Doug |
172 | _______________________________________________ |
173 | busybox mailing list |
174 | busybox@busybox.net |
175 | http://lists.busybox.net/mailman/listinfo/busybox |