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1 | /* dl_dlopen.xs |
2 | * | |
3 | * Platform: SunOS/Solaris, possibly others which use dlopen. | |
4 | * Author: Paul Marquess (pmarquess@bfsec.bt.co.uk) | |
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 | * | |
14 | */ | |
15 | ||
16 | /* Porting notes: | |
17 | ||
18 | ||
19 | Definition of Sunos dynamic Linking functions | |
20 | ============================================= | |
21 | In order to make this implementation easier to understand here is a | |
22 | quick definition of the SunOS Dynamic Linking functions which are | |
23 | used here. | |
24 | ||
25 | dlopen | |
26 | ------ | |
27 | void * | |
28 | dlopen(path, mode) | |
29 | char * path; | |
30 | int mode; | |
31 | ||
32 | This function takes the name of a dynamic object file and returns | |
33 | a descriptor which can be used by dlsym later. It returns NULL on | |
34 | error. | |
35 | ||
36 | The mode parameter must be set to 1 for Solaris 1 and to | |
8e07c86e | 37 | RTLD_LAZY (==2) on Solaris 2. |
a0d0e21e LW |
38 | |
39 | ||
40 | dlsym | |
41 | ------ | |
42 | void * | |
43 | dlsym(handle, symbol) | |
44 | void * handle; | |
45 | char * symbol; | |
46 | ||
47 | Takes the handle returned from dlopen and the name of a symbol to | |
48 | get the address of. If the symbol was found a pointer is | |
49 | returned. It returns NULL on error. If DL_PREPEND_UNDERSCORE is | |
50 | defined an underscore will be added to the start of symbol. This | |
51 | is required on some platforms (freebsd). | |
52 | ||
53 | dlerror | |
54 | ------ | |
55 | char * dlerror() | |
56 | ||
57 | Returns a null-terminated string which describes the last error | |
58 | that occurred with either dlopen or dlsym. After each call to | |
59 | dlerror the error message will be reset to a null pointer. The | |
60 | SaveError function is used to save the error as soo as it happens. | |
61 | ||
62 | ||
63 | Return Types | |
64 | ============ | |
65 | In this implementation the two functions, dl_load_file & | |
66 | dl_find_symbol, return void *. This is because the underlying SunOS | |
67 | dynamic linker calls also return void *. This is not necessarily | |
68 | the case for all architectures. For example, some implementation | |
69 | will want to return a char * for dl_load_file. | |
70 | ||
71 | If void * is not appropriate for your architecture, you will have to | |
72 | change the void * to whatever you require. If you are not certain of | |
73 | how Perl handles C data types, I suggest you start by consulting | |
74 | Dean Roerich's Perl 5 API document. Also, have a look in the typemap | |
75 | file (in the ext directory) for a fairly comprehensive list of types | |
76 | that are already supported. If you are completely stuck, I suggest you | |
13934ef4 | 77 | post a message to perl5-porters, comp.lang.perl.misc or if you are really |
a0d0e21e LW |
78 | desperate to me. |
79 | ||
80 | Remember when you are making any changes that the return value from | |
81 | dl_load_file is used as a parameter in the dl_find_symbol | |
82 | function. Also the return value from find_symbol is used as a parameter | |
83 | to install_xsub. | |
84 | ||
85 | ||
86 | Dealing with Error Messages | |
87 | ============================ | |
88 | In order to make the handling of dynamic linking errors as generic as | |
89 | possible you should store any error messages associated with your | |
90 | implementation with the StoreError function. | |
91 | ||
92 | In the case of SunOS the function dlerror returns the error message | |
93 | associated with the last dynamic link error. As the SunOS dynamic | |
94 | linker functions dlopen & dlsym both return NULL on error every call | |
95 | to a SunOS dynamic link routine is coded like this | |
96 | ||
97 | RETVAL = dlopen(filename, 1) ; | |
98 | if (RETVAL == NULL) | |
99 | SaveError("%s",dlerror()) ; | |
100 | ||
101 | Note that SaveError() takes a printf format string. Use a "%s" as | |
102 | the first parameter if the error may contain and % characters. | |
103 | ||
104 | */ | |
105 | ||
106 | #include "EXTERN.h" | |
107 | #include "perl.h" | |
108 | #include "XSUB.h" | |
109 | ||
110 | #ifdef I_DLFCN | |
111 | #include <dlfcn.h> /* the dynamic linker include file for Sunos/Solaris */ | |
112 | #else | |
113 | #include <nlist.h> | |
114 | #include <link.h> | |
115 | #endif | |
116 | ||
8e07c86e AD |
117 | #ifndef RTLD_LAZY |
118 | # define RTLD_LAZY 1 /* Solaris 1 */ | |
119 | #endif | |
120 | ||
a0d0e21e | 121 | #ifndef HAS_DLERROR |
5d94fbed AD |
122 | # ifdef __NetBSD__ |
123 | # define dlerror() strerror(errno) | |
124 | # else | |
125 | # define dlerror() "Unknown error - dlerror() not implemented" | |
126 | # endif | |
a0d0e21e LW |
127 | #endif |
128 | ||
129 | ||
130 | #include "dlutils.c" /* SaveError() etc */ | |
131 | ||
132 | ||
133 | static void | |
134 | dl_private_init() | |
135 | { | |
136 | (void)dl_generic_private_init(); | |
137 | } | |
138 | ||
139 | MODULE = DynaLoader PACKAGE = DynaLoader | |
140 | ||
141 | BOOT: | |
142 | (void)dl_private_init(); | |
143 | ||
144 | ||
145 | void * | |
146 | dl_load_file(filename) | |
147 | char * filename | |
148 | CODE: | |
8e07c86e AD |
149 | int mode = RTLD_LAZY; |
150 | #ifdef RTLD_NOW | |
151 | if (dl_nonlazy) | |
152 | mode = RTLD_NOW; | |
a0d0e21e LW |
153 | #endif |
154 | DLDEBUG(1,fprintf(stderr,"dl_load_file(%s):\n", filename)); | |
155 | RETVAL = dlopen(filename, mode) ; | |
156 | DLDEBUG(2,fprintf(stderr," libref=%x\n", RETVAL)); | |
157 | ST(0) = sv_newmortal() ; | |
158 | if (RETVAL == NULL) | |
159 | SaveError("%s",dlerror()) ; | |
160 | else | |
161 | sv_setiv( ST(0), (IV)RETVAL); | |
162 | ||
163 | ||
164 | void * | |
165 | dl_find_symbol(libhandle, symbolname) | |
166 | void * libhandle | |
167 | char * symbolname | |
168 | CODE: | |
169 | #ifdef DLSYM_NEEDS_UNDERSCORE | |
170 | char symbolname_buf[1024]; | |
171 | symbolname = dl_add_underscore(symbolname, symbolname_buf); | |
172 | #endif | |
173 | DLDEBUG(2,fprintf(stderr,"dl_find_symbol(handle=%x, symbol=%s)\n", | |
174 | libhandle, symbolname)); | |
175 | RETVAL = dlsym(libhandle, symbolname); | |
176 | DLDEBUG(2,fprintf(stderr," symbolref = %x\n", RETVAL)); | |
177 | ST(0) = sv_newmortal() ; | |
178 | if (RETVAL == NULL) | |
179 | SaveError("%s",dlerror()) ; | |
180 | else | |
181 | sv_setiv( ST(0), (IV)RETVAL); | |
182 | ||
183 | ||
184 | void | |
185 | dl_undef_symbols() | |
186 | PPCODE: | |
187 | ||
188 | ||
189 | ||
190 | # These functions should not need changing on any platform: | |
191 | ||
192 | void | |
193 | dl_install_xsub(perl_name, symref, filename="$Package") | |
194 | char * perl_name | |
195 | void * symref | |
196 | char * filename | |
197 | CODE: | |
198 | DLDEBUG(2,fprintf(stderr,"dl_install_xsub(name=%s, symref=%x)\n", | |
199 | perl_name, symref)); | |
200 | ST(0)=sv_2mortal(newRV((SV*)newXS(perl_name, (void(*)())symref, filename))); | |
201 | ||
202 | ||
203 | char * | |
204 | dl_error() | |
205 | CODE: | |
206 | RETVAL = LastError ; | |
207 | OUTPUT: | |
208 | RETVAL | |
209 | ||
210 | # end. |