| 1 | Description: Allow one to use and switch between different local_scan functions |
| 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 |
| 9 | Last-Update: 2018-12-12 |
| 10 | |
| 11 | --- a/src/EDITME |
| 12 | +++ b/src/EDITME |
| 13 | @@ -824,6 +824,21 @@ HEADERS_CHARSET="ISO-8859-1" |
| 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 |
| 37 | @@ -32,6 +32,8 @@ Do not put spaces between # and the 'def |
| 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 |
| 48 | @@ -141,6 +141,10 @@ int dsn_ret = 0; |
| 49 | const pcre *regex_DSN = NULL; |
| 50 | uschar *dsn_advertise_hosts = NULL; |
| 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 |
| 61 | @@ -138,6 +138,9 @@ extern int dsn_ret; / |
| 62 | extern const pcre *regex_DSN; /* For recognizing DSN settings */ |
| 63 | extern uschar *dsn_advertise_hosts; /* host for which TLS is advertised */ |
| 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 |
| 73 | @@ -5,61 +5,131 @@ |
| 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 | - |
| 85 | -HAVE_LOCAL_SCAN=yes |
| 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" |
| 263 | @@ -192,4 +193,6 @@ extern uschar *string_copy(const uschar |
| 264 | extern uschar *string_copyn(const uschar *, int); |
| 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 |
| 272 | @@ -199,6 +199,9 @@ static optionlist optionlist_config[] = |
| 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 |
| 279 | #ifdef HAVE_LOCAL_SCAN |
| 280 | { "local_scan_timeout", opt_time, &local_scan_timeout }, |
| 281 | #endif |