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54cdb463 | 1 | $Cambridge: exim/doc/doc-txt/NewStuff,v 1.32 2005/04/04 10:33:49 ph10 Exp $ |
495ae4b0 PH |
2 | |
3 | New Features in Exim | |
4 | -------------------- | |
5 | ||
6 | This file contains descriptions of new features that have been added to Exim, | |
7 | but have not yet made it into the main manual (which is most conveniently | |
8 | updated when there is a relatively large batch of changes). The doc/ChangeLog | |
9 | file contains a listing of all changes, including bug fixes. | |
10 | ||
11 | ||
b5aea5e1 PH |
12 | Version 4.51 |
13 | ------------ | |
14 | ||
1a46a8c5 PH |
15 | PH/01 The format in which GnuTLS parameters are written to the gnutls-param |
16 | file in the spool directory has been changed. This change has been made | |
17 | to alleviate problems that some people had with the generation of the | |
18 | parameters by Exim when /dev/random was exhausted. In this situation, | |
19 | Exim would hang until /dev/random acquired some more entropy. | |
20 | ||
21 | The new code exports and imports the DH and RSA parameters in PEM | |
22 | format. This means that the parameters can be generated externally using | |
23 | the certtool command that is part of GnuTLS. | |
24 | ||
25 | To replace the parameters with new ones, instead of deleting the file | |
26 | and letting Exim re-create it, you can generate new parameters using | |
27 | certtool and, when this has been done, replace Exim's cache file by | |
28 | renaming. The relevant commands are something like this: | |
29 | ||
30 | # rm -f new.params | |
31 | # touch new.params | |
32 | # chown exim:exim new.params | |
33 | # chmod 0400 new.params | |
34 | # certtool --generate-privkey --bits 512 >new.params | |
35 | # echo "" >>new.params | |
36 | # certtool --generate-dh-params --bits 1024 >> new.params | |
37 | # mv new.params params | |
38 | ||
39 | If Exim never has to generate the parameters itself, the possibility of | |
40 | stalling is removed. | |
41 | ||
42 | PH/02 A new expansion item for dynamically loading and calling a locally- | |
43 | written C function is now provided, if Exim is compiled with | |
44 | ||
45 | EXPAND_DLFUNC=yes | |
46 | ||
47 | set in Local/Makefile. The facility is not included by default (a | |
48 | suitable error is given if you try to use it when it is not there.) | |
4754440d PH |
49 | |
50 | If you enable EXPAND_DLFUNC, you should also be aware of the new redirect | |
51 | router option forbid_filter_dlfunc. If you have unprivileged users on | |
52 | your system who are permitted to create filter files, you might want to | |
53 | set forbid_filter_dlfunc=true in the appropriate router, to stop them | |
54 | using ${dlfunc to run code within Exim. | |
55 | ||
56 | You load and call an external function like this: | |
1a46a8c5 PH |
57 | |
58 | ${dlfunc{/some/file}{function}{arg1}{arg2}...} | |
59 | ||
4754440d PH |
60 | Once loaded, Exim remembers the dynamically loaded object so that it |
61 | doesn't reload the same object file in the same Exim process (but of | |
62 | course Exim does start new processes frequently). | |
1a46a8c5 PH |
63 | |
64 | There may be from zero to eight arguments to the function. When compiling | |
65 | a local function that is to be called in this way, local_scan.h should be | |
66 | included. The Exim variables and functions that are defined by that API | |
67 | are also available for dynamically loaded functions. The function itself | |
68 | must have the following type: | |
69 | ||
70 | int dlfunction(uschar **yield, int argc, uschar *argv[]) | |
71 | ||
72 | Where "uschar" is a typedef for "unsigned char" in local_scan.h. The | |
73 | function should return one of the following values: | |
74 | ||
75 | OK Success. The string that is placed in "yield" is put into | |
76 | the expanded string that is being built. | |
77 | ||
78 | FAIL A non-forced expansion failure occurs, with the error | |
79 | message taken from "yield", if it is set. | |
80 | ||
81 | FAIL_FORCED A forced expansion failure occurs, with the error message | |
82 | taken from "yield" if it is set. | |
83 | ||
84 | ERROR Same as FAIL, except that a panic log entry is written. | |
85 | ||
86 | When compiling a function that is to be used in this way with gcc, | |
87 | you need to add -shared to the gcc command. Also, in the Exim build-time | |
88 | configuration, you must add -export-dynamic to EXTRALIBS. | |
b5aea5e1 | 89 | |
7dbf77c9 PH |
90 | TF/01 $received_time is a new expansion variable containing the time and date |
91 | as a number of seconds since the start of the Unix epoch when the | |
92 | current message was received. | |
b5aea5e1 | 93 | |
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94 | PH/03 There is a new value for RADIUS_LIB_TYPE that can be set in |
95 | Local/Makefile. It is RADIUSCLIENTNEW, and it requests that the new API, | |
96 | in use from radiusclient 0.4.0 onwards, be used. It does not appear to be | |
97 | possible to detect the different versions automatically. | |
98 | ||
54cdb463 PH |
99 | PH/04 There is a new option called acl_not_smtp_mime that allows you to scan |
100 | MIME parts in non-SMTP messages. It operates in exactly the same way as | |
101 | acl_smtp_mime | |
102 | ||
7766a4f0 | 103 | |
f7b63901 | 104 | Version 4.50 |
35edf2ff PH |
105 | ------------ |
106 | ||
b9e40c51 | 107 | The documentation is up-to-date for the 4.50 release. |
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108 | |
109 | **** |