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01e60269 | 1 | Description: Allow one to use and switch between different local_scan functions |
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2 | without recompiling exim. |
3 | http://marc.merlins.org/linux/exim/files/sa-exim-current/ Original patch from | |
4 | David Woodhouse, modified first by Derrick 'dman' Hudson and then by Marc | |
5 | MERLIN for SA-Exim and minor/major API version tracking | |
6 | Author: David Woodhouse, Derrick 'dman' Hudson, Marc MERLIN | |
7 | Origin: other, http://marc.merlins.org/linux/exim/files/sa-exim-current/ | |
8 | Forwarded: no | |
01e60269 | 9 | Last-Update: 2018-12-12 |
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10 | |
11 | --- a/src/EDITME | |
12 | +++ b/src/EDITME | |
01e60269 | 13 | @@ -824,6 +824,21 @@ HEADERS_CHARSET="ISO-8859-1" |
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14 | |
15 | ||
16 | #------------------------------------------------------------------------------ | |
17 | +# On systems which support dynamic loading of shared libraries, Exim can | |
18 | +# load a local_scan function specified in its config file instead of having | |
19 | +# to be recompiled with the desired local_scan function. For a full | |
20 | +# description of the API to this function, see the Exim specification. | |
21 | + | |
22 | +DLOPEN_LOCAL_SCAN=yes | |
23 | + | |
24 | +# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the | |
25 | +# linker flags. Without it, the loaded .so won't be able to access any | |
26 | +# functions from exim. | |
27 | + | |
28 | +LDFLAGS += -rdynamic | |
29 | +CFLAGS += -fvisibility=hidden | |
30 | + | |
31 | +#------------------------------------------------------------------------------ | |
32 | # The default distribution of Exim contains only the plain text form of the | |
33 | # documentation. Other forms are available separately. If you want to install | |
34 | # the documentation in "info" format, first fetch the Texinfo documentation | |
35 | --- a/src/config.h.defaults | |
36 | +++ b/src/config.h.defaults | |
01e60269 | 37 | @@ -32,6 +32,8 @@ Do not put spaces between # and the 'def |
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38 | |
39 | #define AUTH_VARS 3 | |
40 | ||
41 | +#define DLOPEN_LOCAL_SCAN | |
42 | + | |
43 | #define BIN_DIRECTORY | |
44 | ||
45 | #define CONFIGURE_FILE | |
46 | --- a/src/globals.c | |
47 | +++ b/src/globals.c | |
01e60269 | 48 | @@ -141,6 +141,10 @@ int dsn_ret = 0; |
0baa7b9d | 49 | const pcre *regex_DSN = NULL; |
de45f55a | 50 | uschar *dsn_advertise_hosts = NULL; |
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51 | |
52 | +#ifdef DLOPEN_LOCAL_SCAN | |
53 | +uschar *local_scan_path = NULL; | |
54 | +#endif | |
55 | + | |
56 | #ifdef SUPPORT_TLS | |
57 | BOOL gnutls_compat_mode = FALSE; | |
58 | BOOL gnutls_allow_auto_pkcs11 = FALSE; | |
59 | --- a/src/globals.h | |
60 | +++ b/src/globals.h | |
01e60269 | 61 | @@ -138,6 +138,9 @@ extern int dsn_ret; / |
0baa7b9d | 62 | extern const pcre *regex_DSN; /* For recognizing DSN settings */ |
de45f55a | 63 | extern uschar *dsn_advertise_hosts; /* host for which TLS is advertised */ |
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64 | |
65 | +#ifdef DLOPEN_LOCAL_SCAN | |
66 | +extern uschar *local_scan_path; /* Path to local_scan() library */ | |
67 | +#endif | |
68 | /* Input-reading functions for messages, so we can use special ones for | |
69 | incoming TCP/IP. */ | |
70 | ||
71 | --- a/src/local_scan.c | |
72 | +++ b/src/local_scan.c | |
01e60269 | 73 | @@ -5,61 +5,131 @@ |
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74 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
75 | /* See the file NOTICE for conditions of use and distribution. */ | |
76 | ||
77 | +#include "exim.h" | |
78 | ||
79 | -/****************************************************************************** | |
80 | -This file contains a template local_scan() function that just returns ACCEPT. | |
81 | -If you want to implement your own version, you should copy this file to, say | |
82 | -Local/local_scan.c, and edit the copy. To use your version instead of the | |
83 | -default, you must set | |
84 | - | |
01e60269 | 85 | -HAVE_LOCAL_SCAN=yes |
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86 | -LOCAL_SCAN_SOURCE=Local/local_scan.c |
87 | - | |
88 | -in your Local/Makefile. This makes it easy to copy your version for use with | |
89 | -subsequent Exim releases. | |
90 | - | |
91 | -For a full description of the API to this function, see the Exim specification. | |
92 | -******************************************************************************/ | |
93 | - | |
94 | - | |
95 | -/* This is the only Exim header that you should include. The effect of | |
96 | -including any other Exim header is not defined, and may change from release to | |
97 | -release. Use only the documented interface! */ | |
98 | - | |
99 | -#include "local_scan.h" | |
100 | - | |
101 | - | |
102 | -/* This is a "do-nothing" version of a local_scan() function. The arguments | |
103 | -are: | |
104 | - | |
105 | - fd The file descriptor of the open -D file, which contains the | |
106 | - body of the message. The file is open for reading and | |
107 | - writing, but modifying it is dangerous and not recommended. | |
108 | - | |
109 | - return_text A pointer to an unsigned char* variable which you can set in | |
110 | - order to return a text string. It is initialized to NULL. | |
111 | - | |
112 | -The return values of this function are: | |
113 | - | |
114 | - LOCAL_SCAN_ACCEPT | |
115 | - The message is to be accepted. The return_text argument is | |
116 | - saved in $local_scan_data. | |
117 | - | |
118 | - LOCAL_SCAN_REJECT | |
119 | - The message is to be rejected. The returned text is used | |
120 | - in the rejection message. | |
121 | - | |
122 | - LOCAL_SCAN_TEMPREJECT | |
123 | - This specifies a temporary rejection. The returned text | |
124 | - is used in the rejection message. | |
125 | -*/ | |
126 | +#ifdef DLOPEN_LOCAL_SCAN | |
127 | +#include <dlfcn.h> | |
128 | +static int (*local_scan_fn)(int fd, uschar **return_text) = NULL; | |
129 | +static int load_local_scan_library(void); | |
130 | +#endif | |
131 | ||
132 | int | |
133 | local_scan(int fd, uschar **return_text) | |
134 | { | |
135 | fd = fd; /* Keep picky compilers happy */ | |
136 | return_text = return_text; | |
137 | -return LOCAL_SCAN_ACCEPT; | |
138 | +#ifdef DLOPEN_LOCAL_SCAN | |
139 | +/* local_scan_path is defined AND not the empty string */ | |
140 | +if (local_scan_path && *local_scan_path) | |
141 | + { | |
142 | + if (!local_scan_fn) | |
143 | + { | |
144 | + if (!load_local_scan_library()) | |
145 | + { | |
146 | + char *base_msg , *error_msg , *final_msg ; | |
147 | + int final_length = -1 ; | |
148 | + | |
149 | + base_msg=US"Local configuration error - local_scan() library failure\n"; | |
150 | + error_msg = dlerror() ; | |
151 | + | |
152 | + final_length = strlen(base_msg) + strlen(error_msg) + 1 ; | |
153 | + final_msg = (char*)malloc( final_length*sizeof(char) ) ; | |
154 | + *final_msg = '\0' ; | |
155 | + | |
156 | + strcat( final_msg , base_msg ) ; | |
157 | + strcat( final_msg , error_msg ) ; | |
158 | + | |
159 | + *return_text = final_msg ; | |
160 | + return LOCAL_SCAN_TEMPREJECT; | |
161 | + } | |
162 | + } | |
163 | + return local_scan_fn(fd, return_text); | |
164 | + } | |
165 | +else | |
166 | +#endif | |
167 | + return LOCAL_SCAN_ACCEPT; | |
168 | +} | |
169 | + | |
170 | +#ifdef DLOPEN_LOCAL_SCAN | |
171 | + | |
172 | +static int load_local_scan_library(void) | |
173 | +{ | |
174 | +/* No point in keeping local_scan_lib since we'll never dlclose() anyway */ | |
175 | +void *local_scan_lib = NULL; | |
176 | +int (*local_scan_version_fn)(void); | |
177 | +int vers_maj; | |
178 | +int vers_min; | |
179 | + | |
180 | +local_scan_lib = dlopen(local_scan_path, RTLD_NOW); | |
181 | +if (!local_scan_lib) | |
182 | + { | |
183 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library open failed - " | |
184 | + "message temporarily rejected"); | |
185 | + return FALSE; | |
186 | + } | |
187 | + | |
188 | +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major"); | |
189 | +if (!local_scan_version_fn) | |
190 | + { | |
191 | + dlclose(local_scan_lib); | |
192 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " | |
193 | + "local_scan_version_major() function - message temporarily rejected"); | |
194 | + return FALSE; | |
195 | + } | |
196 | + | |
197 | +/* The major number is increased when the ABI is changed in a non | |
198 | + backward compatible way. */ | |
199 | +vers_maj = local_scan_version_fn(); | |
200 | + | |
201 | +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor"); | |
202 | +if (!local_scan_version_fn) | |
203 | + { | |
204 | + dlclose(local_scan_lib); | |
205 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " | |
206 | + "local_scan_version_minor() function - message temporarily rejected"); | |
207 | + return FALSE; | |
208 | + } | |
209 | + | |
210 | +/* The minor number is increased each time a new feature is added (in a | |
211 | + way that doesn't break backward compatibility) -- Marc */ | |
212 | +vers_min = local_scan_version_fn(); | |
213 | + | |
214 | + | |
215 | +if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR) | |
216 | + { | |
217 | + dlclose(local_scan_lib); | |
218 | + local_scan_lib = NULL; | |
219 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible major" | |
220 | + "version number, you need to recompile your module for this version" | |
221 | + "of exim (The module was compiled for version %d.%d and this exim provides" | |
222 | + "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR, | |
223 | + LOCAL_SCAN_ABI_VERSION_MINOR); | |
224 | + return FALSE; | |
225 | + } | |
226 | +else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR) | |
227 | + { | |
228 | + dlclose(local_scan_lib); | |
229 | + local_scan_lib = NULL; | |
230 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible minor" | |
231 | + "version number, you need to recompile your module for this version" | |
232 | + "of exim (The module was compiled for version %d.%d and this exim provides" | |
233 | + "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR, | |
234 | + LOCAL_SCAN_ABI_VERSION_MINOR); | |
235 | + return FALSE; | |
236 | + } | |
237 | + | |
238 | +local_scan_fn = dlsym(local_scan_lib, "local_scan"); | |
239 | +if (!local_scan_fn) | |
240 | + { | |
241 | + dlclose(local_scan_lib); | |
242 | + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " | |
243 | + "local_scan() function - message temporarily rejected"); | |
244 | + return FALSE; | |
245 | + } | |
246 | + | |
247 | +return TRUE; | |
248 | } | |
249 | ||
250 | +#endif /* DLOPEN_LOCAL_SCAN */ | |
251 | + | |
252 | /* End of local_scan.c */ | |
253 | --- a/src/local_scan.h | |
254 | +++ b/src/local_scan.h | |
255 | @@ -17,6 +17,7 @@ settings, and the store functions. */ | |
256 | ||
257 | #include <stdarg.h> | |
258 | #include <sys/types.h> | |
259 | +#pragma GCC visibility push(default) | |
260 | #include "config.h" | |
261 | #include "mytypes.h" | |
262 | #include "store.h" | |
0baa7b9d SB |
263 | @@ -192,4 +193,6 @@ extern uschar *string_copy(const uschar |
264 | extern uschar *string_copyn(const uschar *, int); | |
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265 | extern uschar *string_sprintf(const char *, ...) ALMOST_PRINTF(1,2); |
266 | ||
267 | +#pragma GCC visibility pop | |
268 | + | |
269 | /* End of local_scan.h */ | |
270 | --- a/src/readconf.c | |
271 | +++ b/src/readconf.c | |
01e60269 | 272 | @@ -199,6 +199,9 @@ static optionlist optionlist_config[] = |
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273 | { "local_from_prefix", opt_stringptr, &local_from_prefix }, |
274 | { "local_from_suffix", opt_stringptr, &local_from_suffix }, | |
275 | { "local_interfaces", opt_stringptr, &local_interfaces }, | |
276 | +#ifdef DLOPEN_LOCAL_SCAN | |
277 | + { "local_scan_path", opt_stringptr, &local_scan_path }, | |
278 | +#endif | |
01e60269 | 279 | #ifdef HAVE_LOCAL_SCAN |
de45f55a | 280 | { "local_scan_timeout", opt_time, &local_scan_timeout }, |
01e60269 | 281 | #endif |