1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
From: Aron Xu <aron@debian.org>
Date: Mon, 13 Feb 2012 15:16:04 +0800
Subject: New flag '-q' to specify a quit timer
---
nc.1 | 10 ++++++++++
netcat.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++-----------
2 files changed, 58 insertions(+), 11 deletions(-)
diff --git a/nc.1 b/nc.1
index 478fedd..fbcc098 100644
--- a/nc.1
+++ b/nc.1
@@ -41,6 +41,7 @@
.Op Fl O Ar length
.Op Fl P Ar proxy_username
.Op Fl p Ar source_port
+.Op Fl q Ar seconds
.Op Fl s Ar sourceaddr
.Op Fl T Ar keyword
.Op Fl V Ar rtable
@@ -167,6 +168,15 @@ Proxy authentication is only supported for HTTP CONNECT proxies at present.
Specify the source port
.Nm
should use, subject to privilege restrictions and availability.
+.It Fl q Ar seconds
+after EOF on stdin, wait the specified number of
+.Ar seconds
+and then quit. If
+.Ar seconds
+is negative, wait forever (default). Specifying a non-negative
+.Ar seconds
+implies
+.Fl N .
.It Fl r
Choose source and/or destination ports randomly
instead of sequentially within a range or in the order that the system
diff --git a/netcat.c b/netcat.c
index 2f3e9a8..03d339c 100644
--- a/netcat.c
+++ b/netcat.c
@@ -139,6 +139,7 @@ int Nflag; /* shutdown() network socket */
int nflag; /* Don't do name look up */
char *Pflag; /* Proxy username */
char *pflag; /* Localport flag */
+int qflag = -1; /* Quit after some secs */
int rflag; /* Random ports flag */
char *sflag; /* Source Address */
int tflag; /* Telnet Emulation */
@@ -223,6 +224,7 @@ ssize_t fillbuf(int, unsigned char *, size_t *);
#endif
static int connect_with_timeout(int, const struct sockaddr *, socklen_t, int);
+static void quit(int sig);
int
main(int argc, char *argv[])
@@ -255,9 +257,9 @@ main(int argc, char *argv[])
while ((ch = getopt(argc, argv,
#ifdef HAVE_TLS
- "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z"))
+ "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:q:R:rSs:T:tUuV:vW:w:X:x:Z:z"))
#else
- "46CDdFhI:i:klM:m:NnO:P:p:rSs:T:tUuV:vW:w:X:x:z"))
+ "46CDdFhI:i:klM:m:NnO:P:p:q:rSs:T:tUuV:vW:w:X:x:z"))
#endif
!= -1) {
switch (ch) {
@@ -349,6 +351,13 @@ main(int argc, char *argv[])
case 'p':
pflag = optarg;
break;
+ case 'q':
+ qflag = strtonum(optarg, INT_MIN, INT_MAX, &errstr);
+ if (errstr)
+ errx(1, "quit timer %s: %s", errstr, optarg);
+ if (qflag >= 0)
+ Nflag = 1;
+ break;
#ifdef HAVE_TLS
case 'R':
tls_cachanged = 1;
@@ -1335,15 +1344,27 @@ readwrite(int net_fd)
while (1) {
/* both inputs are gone, buffers are empty, we are done */
if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 &&
- stdinbufpos == 0 && netinbufpos == 0)
- return;
+ stdinbufpos == 0 && netinbufpos == 0) {
+ if (qflag <= 0)
+ return;
+ goto delay_exit;
+ }
/* both outputs are gone, we can't continue */
- if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1)
- return;
+ if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
+ if (qflag <= 0)
+ return;
+ goto delay_exit;
+ }
/* listen and net in gone, queues empty, done */
if (lflag && pfd[POLL_NETIN].fd == -1 &&
- stdinbufpos == 0 && netinbufpos == 0)
- return;
+ stdinbufpos == 0 && netinbufpos == 0) {
+ if (qflag <= 0)
+ return;
+delay_exit:
+ close(net_fd);
+ signal(SIGALRM, quit);
+ alarm(qflag);
+ }
/* poll */
num_fds = poll(pfd, 4, timeout);
@@ -1500,6 +1521,13 @@ readwrite(int net_fd)
if (pfd[POLL_NETOUT].fd != -1 && Nflag)
shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
pfd[POLL_NETOUT].fd = -1;
+ /* #817050: handle UDP sockets and kflag */
+ if ((lflag || uflag) && pfd[POLL_NETIN].fd != -1 &&
+ qflag >= 0 && netinbufpos == 0) {
+ shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
+ pfd[POLL_NETIN].fd = -1;
+ kflag = 0;
+ }
}
/* net in gone and queue empty? */
if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
@@ -2106,6 +2134,7 @@ help(void)
\t-O length TCP send buffer length\n\
\t-P proxyuser\tUsername for proxy authentication\n\
\t-p port\t Specify local port for remote connects\n\
+ \t-q secs\t quit after EOF on stdin and delay of secs\n\
\t-r Randomize remote ports\n\
\t-S Enable the TCP MD5 signature option\n\
\t-s sourceaddr Local source address\n\
@@ -2130,10 +2159,18 @@ usage(int ret)
fprintf(stderr,
"usage: nc [-46CDdFhklNnrStUuvz] [-I length] [-i interval] [-M ttl]\n"
"\t [-m minttl] [-O length] [-P proxy_username] [-p source_port]\n"
- "\t [-s sourceaddr] [-T keyword] [-V rtable] [-W recvlimit] "
- "[-w timeout]\n"
- "\t [-X proxy_protocol] [-x proxy_address[:port]]\n"
+ "\t [-q seconds] [-s sourceaddr] [-T keyword] [-V rtable] [-W recvlimit]\n"
+ "\t [-w timeout] [-X proxy_protocol] [-x proxy_address[:port]]\n"
"\t [destination] [port]\n");
if (ret)
exit(1);
}
+
+/*
+ * quit()
+ * handler for a "-q" timeout (exit 0 instead of 1)
+ */
+static void quit(__attribute__((unused)) int sig)
+{
+ exit(0);
+}
|
