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1 | .de VS |
2 | .sp 1 |
3 | .RS |
4 | .nf |
5 | .ft B |
6 | .. |
7 | .de VE |
8 | .ft R |
9 | .fi |
10 | .RE |
11 | .sp 1 |
12 | .. |
292b125f |
13 | .TH uopen 1 "5 May 2005" "Straylight/Edgeware" "Preload hacks" |
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14 | .SH NAME |
15 | uopen \- connect to Unix-domain sockets using open(2) |
16 | .SH SYNOPSIS |
17 | .B uopen |
18 | .RI [ command |
19 | .RI [ args ...]] |
20 | .SH DESCRIPTION |
21 | The |
22 | .B uopen |
23 | command runs |
24 | .I command |
25 | (by default, the calling user's shell, as determined by the |
26 | .B SHELL |
27 | environment variable) in an environment where an attempt by the program |
28 | to |
29 | .BR open (2) |
30 | a Unix-domain socket results in a connection being made to the socket. |
31 | .PP |
32 | This might be used to implement a signature server which chooses a |
33 | random signature for newly-written news and mail messages. This can be |
34 | done by writing a simple program to choose and print a signature, |
35 | causing it to be invoked in response to connections to the socket |
36 | .B $HOME/.signature |
37 | (for example, by |
38 | .BR fw (1)) |
39 | and running the message-drafting program under the control of |
40 | .BR uopen . |
41 | If we were willing to accept |
42 | .BR fortune (5) |
43 | as our signature generator, this can be done using, say |
44 | .VS |
45 | fw -d -p$HOME/.sigd.pid \e |
46 | "from unix:$HOME/.signature to exec[fortune -s]" |
47 | uopen emacs -nw -f vm |
48 | .VE |
49 | .SH BUGS |
50 | .B uopen |
51 | is implemented as an |
52 | .B LD_PRELOAD |
53 | hack. It won't work on setuid programs. |
54 | .PP |
55 | The code is needlessly Linux-specific in some places. |
56 | .PP |
57 | It may not catch some uses of |
58 | .BR open (2) |
59 | or its friends from inside the Linux C library. It's a strange and |
60 | murky world in there, and glibc does all manner of strange linker tricks |
61 | to stop you messing with |
62 | .BR open (2). |
63 | .SH SEE ALSO |
64 | .BR fw (1), |
65 | .BR ld.so (8), |
66 | .BR open (2). |
67 | .SH AUTHOR |
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68 | Mark Wooding, <mdw@distorted.org.uk> |