--- a/src/config.h.defaults +++ b/src/config.h.defaults @@ -33,6 +33,8 @@ #define AUTH_VARS 4 +#define DLOPEN_LOCAL_SCAN + #define BIN_DIRECTORY #define CONFIGURE_FILE --- a/src/EDITME +++ b/src/EDITME @@ -904,6 +904,24 @@ #------------------------------------------------------------------------------ +# On systems which support dynamic loading of shared libraries, Exim can +# load a local_scan function specified in its config file instead of having +# to be recompiled with the desired local_scan function. For a full +# description of the API to this function, see the Exim specification. + +#DLOPEN_LOCAL_SCAN=yes + +# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the +# linker flags. Without it, the loaded .so won't be able to access any +# functions from exim. + +LFLAGS = -rdynamic +ifeq ($(OSTYPE),Linux) +LFLAGS += -ldl +endif + + +#------------------------------------------------------------------------------ # The default distribution of Exim contains only the plain text form of the # documentation. Other forms are available separately. If you want to install # the documentation in "info" format, first fetch the Texinfo documentation --- a/src/globals.c +++ b/src/globals.c @@ -43,6 +43,10 @@ uschar *no_aliases = NULL; +#ifdef DLOPEN_LOCAL_SCAN +uschar *local_scan_path = NULL; +#endif + /* For comments on these variables, see globals.h. I'm too idle to duplicate them here... */ --- a/src/globals.h +++ b/src/globals.h @@ -173,6 +173,9 @@ extern int (*receive_feof)(void); extern int (*receive_ferror)(void); +#ifdef DLOPEN_LOCAL_SCAN +extern uschar *local_scan_path; /* Path to local_scan() library */ +#endif /* For clearing, saving, restoring address expansion variables. We have to have the size of this vector set explicitly, because it is referenced from more than --- a/src/local_scan.c +++ b/src/local_scan.c @@ -56,10 +56,130 @@ is used in the rejection message. */ +#ifdef DLOPEN_LOCAL_SCAN +# include +# include +static int (*local_scan_fn)(int fd, uschar **return_text) = NULL; +static int load_local_scan_library(void); +extern uschar *local_scan_path; /* Path to local_scan() library */ +#endif + int local_scan(int fd, uschar **return_text) { -return LOCAL_SCAN_ACCEPT; +#ifdef DLOPEN_LOCAL_SCAN +/* local_scan_path is defined AND not the empty string */ +if (local_scan_path && *local_scan_path) + { + if (!local_scan_fn) + { + if (!load_local_scan_library()) + { + char *base_msg , *error_msg , *final_msg ; + int final_length = -1 ; + + base_msg=US"Local configuration error - local_scan() library failure\n"; + error_msg = dlerror() ; + + final_length = strlen(base_msg) + strlen(error_msg) + 1 ; + final_msg = (char*)malloc( final_length*sizeof(char) ) ; + *final_msg = '\0' ; + + strcat( final_msg , base_msg ) ; + strcat( final_msg , error_msg ) ; + + *return_text = final_msg ; + return LOCAL_SCAN_TEMPREJECT; + } + } + return local_scan_fn(fd, return_text); + } +else +#endif + return LOCAL_SCAN_ACCEPT; +} + +#ifdef DLOPEN_LOCAL_SCAN + +static int load_local_scan_library(void) +{ +/* No point in keeping local_scan_lib since we'll never dlclose() anyway */ +void *local_scan_lib = NULL; +int (*local_scan_version_fn)(void); +int vers_maj; +int vers_min; + +local_scan_lib = dlopen(local_scan_path, RTLD_NOW); +if (!local_scan_lib) + { + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library open failed - " + "message temporarily rejected"); + return FALSE; + } + +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major"); +if (!local_scan_version_fn) + { + dlclose(local_scan_lib); + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " + "local_scan_version_major() function - message temporarily rejected"); + return FALSE; + } + +/* The major number is increased when the ABI is changed in a non + backward compatible way. */ +vers_maj = local_scan_version_fn(); + +local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor"); +if (!local_scan_version_fn) + { + dlclose(local_scan_lib); + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " + "local_scan_version_minor() function - message temporarily rejected"); + return FALSE; + } + +/* The minor number is increased each time a new feature is added (in a + way that doesn't break backward compatibility) -- Marc */ +vers_min = local_scan_version_fn(); + + +if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR) + { + dlclose(local_scan_lib); + local_scan_lib = NULL; + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible major" + "version number, you need to recompile your module for this version" + "of exim (The module was compiled for version %d.%d and this exim provides" + "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR, + LOCAL_SCAN_ABI_VERSION_MINOR); + return FALSE; + } +else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR) + { + dlclose(local_scan_lib); + local_scan_lib = NULL; + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible minor" + "version number, you need to recompile your module for this version" + "of exim (The module was compiled for version %d.%d and this exim provides" + "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR, + LOCAL_SCAN_ABI_VERSION_MINOR); + return FALSE; + } + +local_scan_fn = dlsym(local_scan_lib, "local_scan"); +if (!local_scan_fn) + { + dlclose(local_scan_lib); + log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain " + "local_scan() function - message temporarily rejected"); + return FALSE; + } + +return TRUE; } +#endif /* DLOPEN_LOCAL_SCAN */ + + /* End of local_scan.c */ --- a/src/readconf.c +++ b/src/readconf.c @@ -216,6 +216,9 @@ { "local_from_prefix", opt_stringptr, {&local_from_prefix} }, { "local_from_suffix", opt_stringptr, {&local_from_suffix} }, { "local_interfaces", opt_stringptr, {&local_interfaces} }, +#ifdef DLOPEN_LOCAL_SCAN + { "local_scan_path", opt_stringptr, {&local_scan_path} }, +#endif #ifdef HAVE_LOCAL_SCAN { "local_scan_timeout", opt_time, {&local_scan_timeout} }, #endif