debian/patches/50_localscan_dlopen.dpatch

   1 ## 50_localscan_dlopen.dpatch by Marc MERLIN
   2
   3
   4 Description: Allow to use and switch between different local_scan functions
   5  without recompiling exim.
   6  http://marc.merlins.org/linux/exim/files/sa-exim-current/ Original patch from
   7  David Woodhouse, modified first by Derrick 'dman' Hudson and then by Marc
   8  MERLIN for SA-Exim and minor/major API version tracking
   9 Author: David Woodhouse, Derrick 'dman' Hudson, Marc MERLIN
  10 Origin: other, http://marc.merlins.org/linux/exim/files/sa-exim-current/
  11 Forwarded: no
  12 Last-Update: 2013-09-28
  13
  14 --- a/src/EDITME
  15 +++ b/src/EDITME
  16 @@ -783,6 +783,21 @@ HEADERS_CHARSET="ISO-8859-1"
  17
  18
  19  #------------------------------------------------------------------------------
  20 +# On systems which support dynamic loading of shared libraries, Exim can
  21 +# load a local_scan function specified in its config file instead of having
  22 +# to be recompiled with the desired local_scan function. For a full
  23 +# description of the API to this function, see the Exim specification.
  24 +
  25 +DLOPEN_LOCAL_SCAN=yes
  26 +
  27 +# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the
  28 +# linker flags.  Without it, the loaded .so won't be able to access any
  29 +# functions from exim.
  30 +
  31 +LDFLAGS += -rdynamic
  32 +CFLAGS += -fvisibility=hidden
  33 +
  34 +#------------------------------------------------------------------------------
  35  # The default distribution of Exim contains only the plain text form of the
  36  # documentation. Other forms are available separately. If you want to install
  37  # the documentation in "info" format, first fetch the Texinfo documentation
  38 --- a/src/config.h.defaults
  39 +++ b/src/config.h.defaults
  40 @@ -27,6 +27,8 @@ it's a default value. */
  41
  42  #define AUTH_VARS                     3
  43
  44 +#define DLOPEN_LOCAL_SCAN
  45 +
  46  #define BIN_DIRECTORY
  47
  48  #define CONFIGURE_FILE
  49 --- a/src/globals.c
  50 +++ b/src/globals.c
  51 @@ -134,6 +134,10 @@ BOOL    smtp_use_dsn           = FALSE;
  52  uschar *dsn_advertise_hosts    = NULL;
  53  #endif
  54
  55 +#ifdef DLOPEN_LOCAL_SCAN
  56 +uschar *local_scan_path        = NULL;
  57 +#endif
  58 +
  59  #ifdef SUPPORT_TLS
  60  BOOL    gnutls_compat_mode     = FALSE;
  61  BOOL    gnutls_allow_auto_pkcs11 = FALSE;
  62 --- a/src/globals.h
  63 +++ b/src/globals.h
  64 @@ -134,6 +134,9 @@ extern BOOL     smtp_use_dsn;          /
  65  extern uschar  *dsn_advertise_hosts;   /* host for which TLS is advertised */
  66  #endif
  67
  68 +#ifdef DLOPEN_LOCAL_SCAN
  69 +extern uschar *local_scan_path;        /* Path to local_scan() library */
  70 +#endif
  71  /* Input-reading functions for messages, so we can use special ones for
  72  incoming TCP/IP. */
  73
  74 --- a/src/local_scan.c
  75 +++ b/src/local_scan.c
  76 @@ -5,60 +5,131 @@
  77  /* Copyright (c) University of Cambridge 1995 - 2009 */
  78  /* See the file NOTICE for conditions of use and distribution. */
  79
  80 +#include "exim.h"
  81
  82 -/******************************************************************************
  83 -This file contains a template local_scan() function that just returns ACCEPT.
  84 -If you want to implement your own version, you should copy this file to, say
  85 -Local/local_scan.c, and edit the copy. To use your version instead of the
  86 -default, you must set
  87 -
  88 -LOCAL_SCAN_SOURCE=Local/local_scan.c
  89 -
  90 -in your Local/Makefile. This makes it easy to copy your version for use with
  91 -subsequent Exim releases.
  92 -
  93 -For a full description of the API to this function, see the Exim specification.
  94 -******************************************************************************/
  95 -
  96 -
  97 -/* This is the only Exim header that you should include. The effect of
  98 -including any other Exim header is not defined, and may change from release to
  99 -release. Use only the documented interface! */
 100 -
 101 -#include "local_scan.h"
 102 -
 103 -
 104 -/* This is a "do-nothing" version of a local_scan() function. The arguments
 105 -are:
 106 -
 107 -  fd             The file descriptor of the open -D file, which contains the
 108 -                   body of the message. The file is open for reading and
 109 -                   writing, but modifying it is dangerous and not recommended.
 110 -
 111 -  return_text    A pointer to an unsigned char* variable which you can set in
 112 -                   order to return a text string. It is initialized to NULL.
 113 -
 114 -The return values of this function are:
 115 -
 116 -  LOCAL_SCAN_ACCEPT
 117 -                 The message is to be accepted. The return_text argument is
 118 -                   saved in $local_scan_data.
 119 -
 120 -  LOCAL_SCAN_REJECT
 121 -                 The message is to be rejected. The returned text is used
 122 -                   in the rejection message.
 123 -
 124 -  LOCAL_SCAN_TEMPREJECT
 125 -                 This specifies a temporary rejection. The returned text
 126 -                   is used in the rejection message.
 127 -*/
 128 +#ifdef DLOPEN_LOCAL_SCAN
 129 +#include <dlfcn.h>
 130 +static int (*local_scan_fn)(int fd, uschar **return_text) = NULL;
 131 +static int load_local_scan_library(void);
 132 +#endif
 133
 134  int
 135  local_scan(int fd, uschar **return_text)
 136  {
 137  fd = fd;                      /* Keep picky compilers happy */
 138  return_text = return_text;
 139 -return LOCAL_SCAN_ACCEPT;
 140 +#ifdef DLOPEN_LOCAL_SCAN
 141 +/* local_scan_path is defined AND not the empty string */
 142 +if (local_scan_path && *local_scan_path)
 143 +  {
 144 +  if (!local_scan_fn)
 145 +    {
 146 +    if (!load_local_scan_library())
 147 +      {
 148 +        char *base_msg , *error_msg , *final_msg ;
 149 +        int final_length = -1 ;
 150 +
 151 +        base_msg=US"Local configuration error - local_scan() library failure\n";
 152 +        error_msg = dlerror() ;
 153 +
 154 +        final_length = strlen(base_msg) + strlen(error_msg) + 1 ;
 155 +        final_msg = (char*)malloc( final_length*sizeof(char) ) ;
 156 +        *final_msg = '\0' ;
 157 +
 158 +        strcat( final_msg , base_msg ) ;
 159 +        strcat( final_msg , error_msg ) ;
 160 +
 161 +        *return_text = final_msg ;
 162 +      return LOCAL_SCAN_TEMPREJECT;
 163 +      }
 164 +    }
 165 +    return local_scan_fn(fd, return_text);
 166 +  }
 167 +else
 168 +#endif
 169 +  return LOCAL_SCAN_ACCEPT;
 170 +}
 171 +
 172 +#ifdef DLOPEN_LOCAL_SCAN
 173 +
 174 +static int load_local_scan_library(void)
 175 +{
 176 +/* No point in keeping local_scan_lib since we'll never dlclose() anyway */
 177 +void *local_scan_lib = NULL;
 178 +int (*local_scan_version_fn)(void);
 179 +int vers_maj;
 180 +int vers_min;
 181 +
 182 +local_scan_lib = dlopen(local_scan_path, RTLD_NOW);
 183 +if (!local_scan_lib)
 184 +  {
 185 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library open failed - "
 186 +    "message temporarily rejected");
 187 +  return FALSE;
 188 +  }
 189 +
 190 +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major");
 191 +if (!local_scan_version_fn)
 192 +  {
 193 +  dlclose(local_scan_lib);
 194 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
 195 +    "local_scan_version_major() function - message temporarily rejected");
 196 +  return FALSE;
 197 +  }
 198 +
 199 +/* The major number is increased when the ABI is changed in a non
 200 +   backward compatible way. */
 201 +vers_maj = local_scan_version_fn();
 202 +
 203 +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor");
 204 +if (!local_scan_version_fn)
 205 +  {
 206 +  dlclose(local_scan_lib);
 207 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
 208 +    "local_scan_version_minor() function - message temporarily rejected");
 209 +  return FALSE;
 210 +  }
 211 +
 212 +/* The minor number is increased each time a new feature is added (in a
 213 +   way that doesn't break backward compatibility) -- Marc */
 214 +vers_min = local_scan_version_fn();
 215 +
 216 +
 217 +if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR)
 218 +  {
 219 +  dlclose(local_scan_lib);
 220 +  local_scan_lib = NULL;
 221 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible major"
 222 +    "version number, you need to recompile your module for this version"
 223 +    "of exim (The module was compiled for version %d.%d and this exim provides"
 224 +    "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
 225 +    LOCAL_SCAN_ABI_VERSION_MINOR);
 226 +  return FALSE;
 227 +  }
 228 +else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR)
 229 +  {
 230 +  dlclose(local_scan_lib);
 231 +  local_scan_lib = NULL;
 232 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible minor"
 233 +    "version number, you need to recompile your module for this version"
 234 +    "of exim (The module was compiled for version %d.%d and this exim provides"
 235 +    "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
 236 +    LOCAL_SCAN_ABI_VERSION_MINOR);
 237 +  return FALSE;
 238 +  }
 239 +
 240 +local_scan_fn = dlsym(local_scan_lib, "local_scan");
 241 +if (!local_scan_fn)
 242 +  {
 243 +  dlclose(local_scan_lib);
 244 +  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
 245 +    "local_scan() function - message temporarily rejected");
 246 +  return FALSE;
 247 +  }
 248 +
 249 +return TRUE;
 250  }
 251
 252 +#endif /* DLOPEN_LOCAL_SCAN */
 253 +
 254  /* End of local_scan.c */
 255 --- a/src/local_scan.h
 256 +++ b/src/local_scan.h
 257 @@ -17,6 +17,7 @@ settings, and the store functions. */
 258
 259  #include <stdarg.h>
 260  #include <sys/types.h>
 261 +#pragma GCC visibility push(default)
 262  #include "config.h"
 263  #include "mytypes.h"
 264  #include "store.h"
 265 @@ -194,4 +195,6 @@ extern uschar *string_copy(const uschar
 266  extern uschar *string_copyn(uschar *, int);
 267  extern uschar *string_sprintf(const char *, ...) ALMOST_PRINTF(1,2);
 268
 269 +#pragma GCC visibility pop
 270 +
 271  /* End of local_scan.h */
 272 --- a/src/readconf.c
 273 +++ b/src/readconf.c
 274 @@ -289,6 +289,9 @@ static optionlist optionlist_config[] =
 275    { "local_from_prefix",        opt_stringptr,   &local_from_prefix },
 276    { "local_from_suffix",        opt_stringptr,   &local_from_suffix },
 277    { "local_interfaces",         opt_stringptr,   &local_interfaces },
 278 +#ifdef DLOPEN_LOCAL_SCAN
 279 +  { "local_scan_path",          opt_stringptr,   &local_scan_path },
 280 +#endif
 281    { "local_scan_timeout",       opt_time,        &local_scan_timeout },
 282    { "local_sender_retain",      opt_bool,        &local_sender_retain },
 283    { "localhost_number",         opt_stringptr,   &host_number_string },