1/* dl_dlopen.xs 2 * 3 * Platform: SunOS/Solaris, possibly others which use dlopen. 4 * Author: Paul Marquess (Paul.Marquess@btinternet.com) 5 * Created: 10th July 1994 6 * 7 * Modified: 8 * 15th July 1994 - Added code to explicitly save any error messages. 9 * 3rd August 1994 - Upgraded to v3 spec. 10 * 9th August 1994 - Changed to use IV 11 * 10th August 1994 - Tim Bunce: Added RTLD_LAZY, switchable debugging, 12 * basic FreeBSD support, removed ClearError 13 * 29th Feburary 2000 - Alan Burlison: Added functionality to close dlopen'd 14 * files when the interpreter exits 15 * 16 */ 17 18/* Porting notes: 19 20 21 Definition of Sunos dynamic Linking functions 22 ============================================= 23 In order to make this implementation easier to understand here is a 24 quick definition of the SunOS Dynamic Linking functions which are 25 used here. 26 27 dlopen 28 ------ 29 void * 30 dlopen(path, mode) 31 char * path; 32 int mode; 33 34 This function takes the name of a dynamic object file and returns 35 a descriptor which can be used by dlsym later. It returns NULL on 36 error. 37 38 The mode parameter must be set to 1 for Solaris 1 and to 39 RTLD_LAZY (==2) on Solaris 2. 40 41 42 dlclose 43 ------- 44 int 45 dlclose(handle) 46 void * handle; 47 48 This function takes the handle returned by a previous invocation of 49 dlopen and closes the associated dynamic object file. It returns zero 50 on success, and non-zero on failure. 51 52 53 dlsym 54 ------ 55 void * 56 dlsym(handle, symbol) 57 void * handle; 58 char * symbol; 59 60 Takes the handle returned from dlopen and the name of a symbol to 61 get the address of. If the symbol was found a pointer is 62 returned. It returns NULL on error. If DL_PREPEND_UNDERSCORE is 63 defined an underscore will be added to the start of symbol. This 64 is required on some platforms (freebsd). 65 66 dlerror 67 ------ 68 char * dlerror() 69 70 Returns a null-terminated string which describes the last error 71 that occurred with either dlopen or dlsym. After each call to 72 dlerror the error message will be reset to a null pointer. The 73 SaveError function is used to save the error as soon as it happens. 74 75 76 Return Types 77 ============ 78 In this implementation the two functions, dl_load_file & 79 dl_find_symbol, return void *. This is because the underlying SunOS 80 dynamic linker calls also return void *. This is not necessarily 81 the case for all architectures. For example, some implementation 82 will want to return a char * for dl_load_file. 83 84 If void * is not appropriate for your architecture, you will have to 85 change the void * to whatever you require. If you are not certain of 86 how Perl handles C data types, I suggest you start by consulting 87 Dean Roerich's Perl 5 API document. Also, have a look in the typemap 88 file (in the ext directory) for a fairly comprehensive list of types 89 that are already supported. If you are completely stuck, I suggest you 90 post a message to perl5-porters, comp.lang.perl.misc or if you are really 91 desperate to me. 92 93 Remember when you are making any changes that the return value from 94 dl_load_file is used as a parameter in the dl_find_symbol 95 function. Also the return value from find_symbol is used as a parameter 96 to install_xsub. 97 98 99 Dealing with Error Messages 100 ============================ 101 In order to make the handling of dynamic linking errors as generic as 102 possible you should store any error messages associated with your 103 implementation with the StoreError function. 104 105 In the case of SunOS the function dlerror returns the error message 106 associated with the last dynamic link error. As the SunOS dynamic 107 linker functions dlopen & dlsym both return NULL on error every call 108 to a SunOS dynamic link routine is coded like this 109 110 RETVAL = dlopen(filename, 1) ; 111 if (RETVAL == NULL) 112 SaveError("%s",dlerror()) ; 113 114 Note that SaveError() takes a printf format string. Use a "%s" as 115 the first parameter if the error may contain any % characters. 116 117*/ 118 119#include "EXTERN.h" 120#include "perl.h" 121#include "XSUB.h" 122 123#ifdef I_DLFCN 124#include <dlfcn.h> /* the dynamic linker include file for Sunos/Solaris */ 125#else 126#include <nlist.h> 127#include <link.h> 128#endif 129 130#ifndef RTLD_LAZY 131# define RTLD_LAZY 1 /* Solaris 1 */ 132#endif 133 134#ifndef HAS_DLERROR 135# ifdef __NetBSD__ 136# define dlerror() strerror(errno) 137# else 138# define dlerror() "Unknown error - dlerror() not implemented" 139# endif 140#endif 141 142 143#include "dlutils.c" /* SaveError() etc */ 144 145 146static void 147dl_private_init(pTHX) 148{ 149 (void)dl_generic_private_init(aTHX); 150} 151 152MODULE = DynaLoader PACKAGE = DynaLoader 153 154BOOT: 155 (void)dl_private_init(aTHX); 156 157 158void 159dl_load_file(filename, flags=0) 160 char * filename 161 int flags 162 PREINIT: 163 int mode = RTLD_LAZY; 164 void *handle; 165 CODE: 166{ 167#if defined(DLOPEN_WONT_DO_RELATIVE_PATHS) 168 char pathbuf[PATH_MAX + 2]; 169 if (*filename != '/' && strchr(filename, '/')) { 170 if (getcwd(pathbuf, PATH_MAX - strlen(filename))) { 171 strcat(pathbuf, "/"); 172 strcat(pathbuf, filename); 173 filename = pathbuf; 174 } 175 } 176#endif 177#ifdef RTLD_NOW 178 { 179 dMY_CXT; 180 if (dl_nonlazy) 181 mode = RTLD_NOW; 182 } 183#endif 184 if (flags & 0x01) 185#ifdef RTLD_GLOBAL 186 mode |= RTLD_GLOBAL; 187#else 188 Perl_warn(aTHX_ "Can't make loaded symbols global on this platform while loading %s",filename); 189#endif 190 DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_load_file(%s,%x):\n", filename,flags)); 191 handle = dlopen(filename, mode) ; 192 DLDEBUG(2,PerlIO_printf(Perl_debug_log, " libref=%lx\n", (unsigned long) handle)); 193 ST(0) = sv_newmortal() ; 194 if (handle == NULL) 195 SaveError(aTHX_ "%s",dlerror()) ; 196 else 197 sv_setiv( ST(0), PTR2IV(handle)); 198} 199 200 201int 202dl_unload_file(libref) 203 void * libref 204 CODE: 205 DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_unload_file(%lx):\n", PTR2ul(libref))); 206 RETVAL = (dlclose(libref) == 0 ? 1 : 0); 207 if (!RETVAL) 208 SaveError(aTHX_ "%s", dlerror()) ; 209 DLDEBUG(2,PerlIO_printf(Perl_debug_log, " retval = %d\n", RETVAL)); 210 OUTPUT: 211 RETVAL 212 213 214void 215dl_find_symbol(libhandle, symbolname) 216 void * libhandle 217 char * symbolname 218 PREINIT: 219 void *sym; 220 CODE: 221#ifdef DLSYM_NEEDS_UNDERSCORE 222 symbolname = Perl_form_nocontext("_%s", symbolname); 223#endif 224 DLDEBUG(2, PerlIO_printf(Perl_debug_log, 225 "dl_find_symbol(handle=%lx, symbol=%s)\n", 226 (unsigned long) libhandle, symbolname)); 227 sym = dlsym(libhandle, symbolname); 228 DLDEBUG(2, PerlIO_printf(Perl_debug_log, 229 " symbolref = %lx\n", (unsigned long) sym)); 230 ST(0) = sv_newmortal() ; 231 if (sym == NULL) 232 SaveError(aTHX_ "%s",dlerror()) ; 233 else 234 sv_setiv( ST(0), PTR2IV(sym)); 235 236 237void 238dl_undef_symbols() 239 CODE: 240 241 242 243# These functions should not need changing on any platform: 244 245void 246dl_install_xsub(perl_name, symref, filename="$Package") 247 char * perl_name 248 void * symref 249 char * filename 250 CODE: 251 DLDEBUG(2,PerlIO_printf(Perl_debug_log, "dl_install_xsub(name=%s, symref=%lx)\n", 252 perl_name, (unsigned long) symref)); 253 ST(0) = sv_2mortal(newRV((SV*)newXS(perl_name, 254 (void(*)(pTHX_ CV *))symref, 255 filename))); 256 257 258char * 259dl_error() 260 CODE: 261 dMY_CXT; 262 RETVAL = dl_last_error ; 263 OUTPUT: 264 RETVAL 265 266# end. 267