/* dynl.c - dynamic linking Copyright 1990-2003,2008-2011,2017-2018 Free Software Foundation, Inc. This file is part of Guile. Guile is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Guile is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with Guile. If not, see . */ /* "dynl.c" dynamically link&load object files. Author: Aubrey Jaffer Modified for libguile by Marius Vollmer */ #ifdef HAVE_CONFIG_H # include #endif #include #include #include #include #include #include "deprecation.h" #include "dynwind.h" #include "foreign.h" #include "gc.h" #include "gsubr.h" #include "keywords.h" #include "libpath.h" #include "list.h" #include "ports.h" #include "smob.h" #include "strings.h" #include "threads.h" #include "dynl.h" /* From the libtool manual: "Note that libltdl is not threadsafe, i.e. a multithreaded application has to use a mutex for libltdl.". Note: We initialize it as a recursive mutex below. */ static scm_i_pthread_mutex_t ltdl_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER; /* LT_PATH_SEP-separated extension library search path, searched last */ static char *system_extensions_path; static void * sysdep_dynl_link (const char *fname, const char *subr) { lt_dlhandle handle; if (fname == NULL) /* Return a handle for the program as a whole. */ handle = lt_dlopen (NULL); else { handle = lt_dlopenext (fname); if (handle == NULL #ifdef LT_DIRSEP_CHAR && strchr (fname, LT_DIRSEP_CHAR) == NULL #endif && strchr (fname, '/') == NULL) { /* FNAME contains no directory separators and was not in the usual library search paths, so now we search for it in SYSTEM_EXTENSIONS_PATH. */ char *fname_attempt = scm_gc_malloc_pointerless (strlen (system_extensions_path) + strlen (fname) + 2, "dynl fname_attempt"); char *path; /* remaining path to search */ char *end; /* end of current path component */ char *s; /* Iterate over the components of SYSTEM_EXTENSIONS_PATH */ for (path = system_extensions_path; *path != '\0'; path = (*end == '\0') ? end : (end + 1)) { /* Find end of path component */ end = strchr (path, LT_PATHSEP_CHAR); if (end == NULL) end = strchr (path, '\0'); /* Skip empty path components */ if (path == end) continue; /* Construct FNAME_ATTEMPT, starting with path component */ s = fname_attempt; memcpy (s, path, end - path); s += end - path; /* Append directory separator, but avoid duplicates */ if (s[-1] != '/' #ifdef LT_DIRSEP_CHAR && s[-1] != LT_DIRSEP_CHAR #endif ) *s++ = '/'; /* Finally, append FNAME (including null terminator) */ strcpy (s, fname); /* Try to load it, and terminate the search if successful */ handle = lt_dlopenext (fname_attempt); if (handle != NULL) break; } } } if (handle == NULL) { SCM fn; SCM msg; fn = fname != NULL ? scm_from_locale_string (fname) : SCM_BOOL_F; msg = scm_from_locale_string (lt_dlerror ()); scm_misc_error (subr, "file: ~S, message: ~S", scm_list_2 (fn, msg)); } return (void *) handle; } static void sysdep_dynl_unlink (void *handle, const char *subr) { if (lt_dlclose ((lt_dlhandle) handle)) { scm_misc_error (subr, (char *) lt_dlerror (), SCM_EOL); } } static void * sysdep_dynl_value (const char *symb, void *handle, const char *subr) { void *fptr; fptr = lt_dlsym ((lt_dlhandle) handle, symb); if (!fptr) scm_misc_error (subr, "Symbol not found: ~a", scm_list_1 (scm_from_locale_string (symb))); return fptr; } static void sysdep_dynl_init () { char *env; lt_dlinit (); /* Initialize 'system_extensions_path' from $GUILE_SYSTEM_EXTENSIONS_PATH, or if that's not set: . 'lt_dladdsearchdir' can't be used because it is searched before the system-dependent search path, which is the one 'libtool --mode=execute -dlopen' fiddles with (info "(libtool) Libltdl Interface"). See . The environment variables $LTDL_LIBRARY_PATH and $LD_LIBRARY_PATH can't be used because they would be propagated to subprocesses which may cause problems for other programs. See */ env = getenv ("GUILE_SYSTEM_EXTENSIONS_PATH"); if (env) system_extensions_path = env; else { system_extensions_path = scm_gc_malloc_pointerless (strlen (SCM_LIB_DIR) + strlen (SCM_EXTENSIONS_DIR) + 2, "system_extensions_path"); sprintf (system_extensions_path, "%s%c%s", SCM_LIB_DIR, LT_PATHSEP_CHAR, SCM_EXTENSIONS_DIR); } } scm_t_bits scm_tc16_dynamic_obj; #define DYNL_FILENAME SCM_SMOB_OBJECT #define DYNL_HANDLE(x) ((void *) SCM_SMOB_DATA_2 (x)) #define SET_DYNL_HANDLE(x, v) (SCM_SET_SMOB_DATA_2 ((x), (scm_t_bits) (v))) static int dynl_obj_print (SCM exp, SCM port, scm_print_state *pstate) { scm_puts ("#', port); return 1; } SCM_DEFINE (scm_dynamic_link, "dynamic-link", 0, 1, 0, (SCM filename), "Find the shared object (shared library) denoted by\n" "@var{filename} and link it into the running Guile\n" "application. The returned\n" "scheme object is a ``handle'' for the library which can\n" "be passed to @code{dynamic-func}, @code{dynamic-call} etc.\n\n" "Searching for object files is system dependent. Normally,\n" "if @var{filename} does have an explicit directory it will\n" "be searched for in locations\n" "such as @file{/usr/lib} and @file{/usr/local/lib}.\n\n" "When @var{filename} is omitted, a @dfn{global symbol handle} is\n" "returned. This handle provides access to the symbols\n" "available to the program at run-time, including those exported\n" "by the program itself and the shared libraries already loaded.\n") #define FUNC_NAME s_scm_dynamic_link { void *handle; char *file; scm_dynwind_begin (0); scm_i_dynwind_pthread_mutex_lock (<dl_lock); if (SCM_UNBNDP (filename)) file = NULL; else { file = scm_to_locale_string (filename); scm_dynwind_free (file); } handle = sysdep_dynl_link (file, FUNC_NAME); scm_dynwind_end (); SCM_RETURN_NEWSMOB2 (scm_tc16_dynamic_obj, SCM_UNBNDP (filename) ? SCM_UNPACK (SCM_BOOL_F) : SCM_UNPACK (filename), handle); } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_object_p, "dynamic-object?", 1, 0, 0, (SCM obj), "Return @code{#t} if @var{obj} is a dynamic object handle,\n" "or @code{#f} otherwise.") #define FUNC_NAME s_scm_dynamic_object_p { return scm_from_bool (SCM_TYP16_PREDICATE (scm_tc16_dynamic_obj, obj)); } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_unlink, "dynamic-unlink", 1, 0, 0, (SCM dobj), "Unlink a dynamic object from the application, if possible. The\n" "object must have been linked by @code{dynamic-link}, with \n" "@var{dobj} the corresponding handle. After this procedure\n" "is called, the handle can no longer be used to access the\n" "object.") #define FUNC_NAME s_scm_dynamic_unlink { /*fixme* GC-problem */ SCM_VALIDATE_SMOB (SCM_ARG1, dobj, dynamic_obj); scm_dynwind_begin (0); scm_i_dynwind_pthread_mutex_lock (<dl_lock); if (DYNL_HANDLE (dobj) == NULL) { SCM_MISC_ERROR ("Already unlinked: ~S", scm_list_1 (dobj)); } else { sysdep_dynl_unlink (DYNL_HANDLE (dobj), FUNC_NAME); SET_DYNL_HANDLE (dobj, NULL); } scm_dynwind_end (); return SCM_UNSPECIFIED; } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_pointer, "dynamic-pointer", 2, 0, 0, (SCM name, SCM dobj), "Return a ``wrapped pointer'' to the symbol @var{name}\n" "in the shared object referred to by @var{dobj}. The returned\n" "pointer points to a C object.\n\n" "Regardless whether your C compiler prepends an underscore\n" "@samp{_} to the global names in a program, you should\n" "@strong{not} include this underscore in @var{name}\n" "since it will be added automatically when necessary.") #define FUNC_NAME s_scm_dynamic_pointer { void *val; SCM_VALIDATE_STRING (1, name); SCM_VALIDATE_SMOB (SCM_ARG2, dobj, dynamic_obj); if (DYNL_HANDLE (dobj) == NULL) SCM_MISC_ERROR ("Already unlinked: ~S", dobj); else { char *chars; scm_dynwind_begin (0); scm_i_dynwind_pthread_mutex_lock (<dl_lock); chars = scm_to_locale_string (name); scm_dynwind_free (chars); val = sysdep_dynl_value (chars, DYNL_HANDLE (dobj), FUNC_NAME); scm_dynwind_end (); return scm_from_pointer (val, NULL); } } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_func, "dynamic-func", 2, 0, 0, (SCM name, SCM dobj), "Return a ``handle'' for the function @var{name} in the\n" "shared object referred to by @var{dobj}. The handle\n" "can be passed to @code{dynamic-call} to actually\n" "call the function.\n\n" "Regardless whether your C compiler prepends an underscore\n" "@samp{_} to the global names in a program, you should\n" "@strong{not} include this underscore in @var{name}\n" "since it will be added automatically when necessary.") #define FUNC_NAME s_scm_dynamic_func { return scm_dynamic_pointer (name, dobj); } #undef FUNC_NAME SCM_DEFINE (scm_dynamic_call, "dynamic-call", 2, 0, 0, (SCM func, SCM dobj), "Call a C function in a dynamic object. Two styles of\n" "invocation are supported:\n\n" "@itemize @bullet\n" "@item @var{func} can be a function handle returned by\n" "@code{dynamic-func}. In this case @var{dobj} is\n" "ignored\n" "@item @var{func} can be a string with the name of the\n" "function to call, with @var{dobj} the handle of the\n" "dynamic object in which to find the function.\n" "This is equivalent to\n" "@smallexample\n\n" "(dynamic-call (dynamic-func @var{func} @var{dobj}) #f)\n" "@end smallexample\n" "@end itemize\n\n" "In either case, the function is passed no arguments\n" "and its return value is ignored.") #define FUNC_NAME s_scm_dynamic_call { void (*fptr) (void); if (scm_is_string (func)) func = scm_dynamic_func (func, dobj); SCM_VALIDATE_POINTER (SCM_ARG1, func); fptr = SCM_POINTER_VALUE (func); fptr (); return SCM_UNSPECIFIED; } #undef FUNC_NAME void scm_init_dynamic_linking () { scm_tc16_dynamic_obj = scm_make_smob_type ("dynamic-object", 0); scm_set_smob_print (scm_tc16_dynamic_obj, dynl_obj_print); /* Make LTDL_LOCK recursive so that a pre-unwind handler can still use 'dynamic-link', as is the case at the REPL. See . */ scm_i_pthread_mutex_init (<dl_lock, scm_i_pthread_mutexattr_recursive); sysdep_dynl_init (); #include "dynl.x" }