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1 | /* dl_dlopen.xs |
2 | * |
3 | * Platform: SunOS/Solaris, possibly others which use dlopen. |
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4 | * Author: Paul Marquess (Paul.Marquess@btinternet.com) |
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5 | * Created: 10th July 1994 |
6 | * |
7 | * Modified: |
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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 |
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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 |
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39 | RTLD_LAZY (==2) on Solaris 2. |
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40 | |
41 | |
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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 | |
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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 |
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73 | SaveError function is used to save the error as soon as it happens. |
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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 |
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90 | post a message to perl5-porters, comp.lang.perl.misc or if you are really |
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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 |
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115 | the first parameter if the error may contain any % characters. |
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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 | |
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130 | #ifndef RTLD_LAZY |
131 | # define RTLD_LAZY 1 /* Solaris 1 */ |
132 | #endif |
133 | |
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134 | #ifndef HAS_DLERROR |
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135 | # ifdef __NetBSD__ |
136 | # define dlerror() strerror(errno) |
137 | # else |
138 | # define dlerror() "Unknown error - dlerror() not implemented" |
139 | # endif |
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140 | #endif |
141 | |
142 | |
143 | #include "dlutils.c" /* SaveError() etc */ |
144 | |
145 | |
146 | static void |
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147 | dl_private_init(pTHX) |
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148 | { |
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149 | (void)dl_generic_private_init(aTHX); |
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150 | } |
151 | |
152 | MODULE = DynaLoader PACKAGE = DynaLoader |
153 | |
154 | BOOT: |
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155 | (void)dl_private_init(aTHX); |
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156 | |
157 | |
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158 | void |
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159 | dl_load_file(filename, flags=0) |
160 | char * filename |
161 | int flags |
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162 | PREINIT: |
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163 | int mode = RTLD_LAZY; |
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164 | void *handle; |
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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 |
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177 | #ifdef RTLD_NOW |
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178 | { |
179 | dMY_CXT; |
180 | if (dl_nonlazy) |
181 | mode = RTLD_NOW; |
182 | } |
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183 | #endif |
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184 | if (flags & 0x01) |
185 | #ifdef RTLD_GLOBAL |
186 | mode |= RTLD_GLOBAL; |
187 | #else |
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188 | Perl_warn(aTHX_ "Can't make loaded symbols global on this platform while loading %s",filename); |
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189 | #endif |
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190 | DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_load_file(%s,%x):\n", filename,flags)); |
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191 | handle = dlopen(filename, mode) ; |
192 | DLDEBUG(2,PerlIO_printf(Perl_debug_log, " libref=%lx\n", (unsigned long) handle)); |
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193 | ST(0) = sv_newmortal() ; |
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194 | if (handle == NULL) |
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195 | SaveError(aTHX_ "%s",dlerror()) ; |
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196 | else |
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197 | sv_setiv( ST(0), PTR2IV(handle)); |
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198 | } |
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199 | |
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200 | |
201 | int |
202 | dl_unload_file(libref) |
203 | void * libref |
204 | CODE: |
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205 | DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_unload_file(%lx):\n", PTR2ul(libref))); |
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206 | RETVAL = (dlclose(libref) == 0 ? 1 : 0); |
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207 | if (!RETVAL) |
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208 | SaveError(aTHX_ "%s", dlerror()) ; |
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209 | DLDEBUG(2,PerlIO_printf(Perl_debug_log, " retval = %d\n", RETVAL)); |
210 | OUTPUT: |
211 | RETVAL |
212 | |
213 | |
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214 | void |
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215 | dl_find_symbol(libhandle, symbolname) |
216 | void * libhandle |
217 | char * symbolname |
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218 | PREINIT: |
219 | void *sym; |
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220 | CODE: |
221 | #ifdef DLSYM_NEEDS_UNDERSCORE |
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222 | symbolname = Perl_form_nocontext("_%s", symbolname); |
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223 | #endif |
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224 | DLDEBUG(2, PerlIO_printf(Perl_debug_log, |
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225 | "dl_find_symbol(handle=%lx, symbol=%s)\n", |
226 | (unsigned long) libhandle, symbolname)); |
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227 | sym = dlsym(libhandle, symbolname); |
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228 | DLDEBUG(2, PerlIO_printf(Perl_debug_log, |
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229 | " symbolref = %lx\n", (unsigned long) sym)); |
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230 | ST(0) = sv_newmortal() ; |
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231 | if (sym == NULL) |
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232 | SaveError(aTHX_ "%s",dlerror()) ; |
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233 | else |
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234 | sv_setiv( ST(0), PTR2IV(sym)); |
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235 | |
236 | |
237 | void |
238 | dl_undef_symbols() |
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239 | CODE: |
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240 | |
241 | |
242 | |
243 | # These functions should not need changing on any platform: |
244 | |
245 | void |
246 | dl_install_xsub(perl_name, symref, filename="$Package") |
247 | char * perl_name |
248 | void * symref |
249 | char * filename |
250 | CODE: |
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251 | DLDEBUG(2,PerlIO_printf(Perl_debug_log, "dl_install_xsub(name=%s, symref=%"UVxf")\n", |
252 | perl_name, PTR2UV(symref))); |
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253 | ST(0) = sv_2mortal(newRV((SV*)newXS_flags(perl_name, |
254 | DPTR2FPTR(XSUBADDR_t, symref), |
255 | filename, NULL, |
256 | XS_DYNAMIC_FILENAME))); |
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257 | |
258 | |
259 | char * |
260 | dl_error() |
261 | CODE: |
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262 | dMY_CXT; |
263 | RETVAL = dl_last_error ; |
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264 | OUTPUT: |
265 | RETVAL |
266 | |
267 | # end. |