Commit | Line | Data |
03c9e98c |
1 | use Config; |
2 | |
3 | sub to_string { |
4 | my ($value) = @_; |
146174a9 |
5 | $value =~ s/\\/\\\\/g; |
03c9e98c |
6 | $value =~ s/'/\\'/g; |
7 | return "'$value'"; |
8 | } |
9 | |
10 | unlink "DynaLoader.pm" if -f "DynaLoader.pm"; |
11 | open OUT, ">DynaLoader.pm" or die $!; |
12 | print OUT <<'EOT'; |
13 | |
d0a5ed9f |
14 | # Generated from DynaLoader.pm.PL |
03c9e98c |
15 | |
a0d0e21e |
16 | package DynaLoader; |
17 | |
8e07c86e |
18 | # And Gandalf said: 'Many folk like to know beforehand what is to |
19 | # be set on the table; but those who have laboured to prepare the |
20 | # feast like to keep their secret; for wonder makes the words of |
21 | # praise louder.' |
22 | |
6662521e |
23 | # (Quote from Tolkien suggested by Anno Siegel.) |
8e07c86e |
24 | # |
25 | # See pod text at end of file for documentation. |
26 | # See also ext/DynaLoader/README in source tree for other information. |
27 | # |
28 | # Tim.Bunce@ig.co.uk, August 1994 |
29 | |
632a9a7f |
30 | use vars qw($VERSION *AUTOLOAD); |
31 | |
32 | $VERSION = 1.04; # avoid typo warning |
dc848c6f |
33 | |
dc848c6f |
34 | require AutoLoader; |
35 | *AUTOLOAD = \&AutoLoader::AUTOLOAD; |
8e07c86e |
36 | |
7e9f3af8 |
37 | use Config; |
38 | |
fb73857a |
39 | # The following require can't be removed during maintenance |
40 | # releases, sadly, because of the risk of buggy code that does |
41 | # require Carp; Carp::croak "..."; without brackets dying |
42 | # if Carp hasn't been loaded in earlier compile time. :-( |
43 | # We'll let those bugs get found on the development track. |
44 | require Carp if $] < 5.00450; |
45 | |
8e07c86e |
46 | # enable debug/trace messages from DynaLoader perl code |
47 | $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug; |
48 | |
ff7f3c60 |
49 | # |
50 | # Flags to alter dl_load_file behaviour. Assigned bits: |
51 | # 0x01 make symbols available for linking later dl_load_file's. |
52 | # (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) |
f86702cc |
53 | # (ignored under VMS; effect is built-in to image linking) |
ff7f3c60 |
54 | # |
55 | # This is called as a class method $module->dl_load_flags. The |
56 | # definition here will be inherited and result on "default" loading |
57 | # behaviour unless a sub-class of DynaLoader defines its own version. |
58 | # |
59 | |
60 | sub dl_load_flags { 0x00 } |
61 | |
03c9e98c |
62 | # ($dl_dlext, $dlsrc) |
63 | # = @Config::Config{'dlext', 'dlsrc'}; |
64 | EOT |
65 | |
66 | print OUT " (\$dl_dlext, \$dlsrc) = (", |
67 | to_string($Config::Config{'dlext'}), ",", |
68 | to_string($Config::Config{'dlsrc'}), ")\n;" ; |
ff7f3c60 |
69 | |
03c9e98c |
70 | print OUT <<'EOT'; |
8e07c86e |
71 | |
72 | # Some systems need special handling to expand file specifications |
73 | # (VMS support by Charles Bailey <bailey@HMIVAX.HUMGEN.UPENN.EDU>) |
74 | # See dl_expandspec() for more details. Should be harmless but |
75 | # inefficient to define on systems that don't need it. |
632a9a7f |
76 | $Is_VMS = $^O eq 'VMS'; |
77 | $do_expand = $Is_VMS; |
78 | $Is_MacOS = $^O eq 'MacOS'; |
8e07c86e |
79 | |
80 | @dl_require_symbols = (); # names of symbols we need |
81 | @dl_resolve_using = (); # names of files to link with |
82 | @dl_library_path = (); # path to look for files |
632a9a7f |
83 | @dl_librefs = (); # things we have loaded |
84 | @dl_modules = (); # Modules we have loaded |
8e07c86e |
85 | |
86 | # This is a fix to support DLD's unfortunate desire to relink -lc |
87 | @dl_resolve_using = dl_findfile('-lc') if $dlsrc eq "dl_dld.xs"; |
88 | |
d0a5ed9f |
89 | EOT |
03c9e98c |
90 | |
d0a5ed9f |
91 | my $cfg_dl_library_path = <<'EOT'; |
632a9a7f |
92 | push(@dl_library_path, split(' ', $Config::Config{libpth})); |
03c9e98c |
93 | EOT |
94 | |
d0a5ed9f |
95 | sub dquoted_comma_list { |
96 | join(", ", map {qq("$_")} @_); |
97 | } |
03c9e98c |
98 | |
d0a5ed9f |
99 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) { |
100 | eval $cfg_dl_library_path; |
101 | if (!$ENV{PERL_BUILD_EXPAND_ENV_VARS}) { |
102 | my $dl_library_path = dquoted_comma_list(@dl_library_path); |
103 | print OUT <<EOT; |
7e9f3af8 |
104 | # The below \@dl_library_path has been expanded (%Config) in Perl build time. |
d0a5ed9f |
105 | |
106 | \@dl_library_path = ($dl_library_path); |
107 | |
108 | EOT |
109 | } |
110 | } |
111 | else { |
112 | print OUT <<EOT; |
113 | # Initialise \@dl_library_path with the 'standard' library path |
114 | # for this platform as determined by Configure. |
115 | |
116 | $cfg_dl_library_path |
117 | |
118 | EOT |
119 | } |
8e07c86e |
120 | |
8225e35f |
121 | my $ldlibpthname; |
7e9f3af8 |
122 | my $ldlibpthname_defined; |
8225e35f |
123 | my $pthsep; |
124 | |
125 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) { |
7e9f3af8 |
126 | $ldlibpthname = $Config::Config{ldlibpthname}; |
127 | $ldlibpthname_defined = defined $Config::Config{ldlibpthname} ? 1 : 0; |
128 | $pthsep = $Config::Config{path_sep}; |
8225e35f |
129 | } |
130 | else { |
7e9f3af8 |
131 | $ldlibpthname = q($Config::Config{ldlibpthname}); |
132 | $ldlibpthname_defined = q(defined $Config::Config{ldlibpthname}); |
133 | $pthsep = q($Config::Config{path_sep}); |
8225e35f |
134 | print OUT <<EOT; |
7e9f3af8 |
135 | my \$ldlibpthname = $ldlibpthname; |
136 | my \$ldlibpthname_defined = $ldlibpthname_defined; |
137 | my \$pthsep = $pthsep; |
8225e35f |
138 | |
139 | EOT |
140 | } |
141 | |
7e9f3af8 |
142 | my $env_dl_library_path = <<'EOT'; |
143 | if ($ldlibpthname_defined && |
144 | exists $ENV{$ldlibpthname}) { |
145 | push(@dl_library_path, split(/$pthsep/, $ENV{$ldlibpthname})); |
8225e35f |
146 | } |
147 | |
5cf1d1f1 |
148 | # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH. |
8225e35f |
149 | |
7e9f3af8 |
150 | if ($ldlibpthname_defined && |
151 | $ldlibpthname ne 'LD_LIBRARY_PATH' && |
152 | exists $ENV{LD_LIBRARY_PATH}) { |
153 | push(@dl_library_path, split(/$pthsep/, $ENV{LD_LIBRARY_PATH})); |
d0a5ed9f |
154 | } |
e6197cab |
155 | EOT |
156 | |
d0a5ed9f |
157 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS} && $ENV{PERL_BUILD_EXPAND_ENV_VARS}) { |
158 | eval $env_dl_library_path; |
e6197cab |
159 | } |
d0a5ed9f |
160 | else { |
161 | print OUT <<EOT; |
162 | # Add to \@dl_library_path any extra directories we can gather from environment |
163 | # during runtime. |
e6197cab |
164 | |
d0a5ed9f |
165 | $env_dl_library_path |
166 | |
167 | EOT |
e6197cab |
168 | } |
169 | |
d0a5ed9f |
170 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS} && $ENV{PERL_BUILD_EXPAND_ENV_VARS}) { |
171 | my $dl_library_path = dquoted_comma_list(@dl_library_path); |
172 | print OUT <<EOT; |
7e9f3af8 |
173 | # The below \@dl_library_path has been expanded (%Config, %ENV) |
174 | # in Perl build time. |
d0a5ed9f |
175 | |
176 | \@dl_library_path = ($dl_library_path); |
177 | |
178 | EOT |
146174a9 |
179 | } |
8e07c86e |
180 | |
d0a5ed9f |
181 | print OUT <<'EOT'; |
8e07c86e |
182 | # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. |
b4cea227 |
183 | # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB |
bb3913c7 |
184 | boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && |
b4cea227 |
185 | !defined(&dl_error); |
8e07c86e |
186 | |
187 | if ($dl_debug) { |
188 | print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n"; |
189 | print STDERR "DynaLoader not linked into this perl\n" |
190 | unless defined(&boot_DynaLoader); |
191 | } |
192 | |
193 | 1; # End of main code |
194 | |
195 | |
fb73857a |
196 | sub croak { require Carp; Carp::croak(@_) } |
197 | |
146174a9 |
198 | sub bootstrap_inherit { |
199 | my $module = $_[0]; |
200 | local *isa = *{"$module\::ISA"}; |
201 | local @isa = (@isa, 'DynaLoader'); |
202 | # Cannot goto due to delocalization. Will report errors on a wrong line? |
203 | bootstrap(@_); |
204 | } |
205 | |
8e07c86e |
206 | # The bootstrap function cannot be autoloaded (without complications) |
207 | # so we define it here: |
208 | |
209 | sub bootstrap { |
210 | # use local vars to enable $module.bs script to edit values |
211 | local(@args) = @_; |
212 | local($module) = $args[0]; |
213 | local(@dirs, $file); |
214 | |
fb73857a |
215 | unless ($module) { |
216 | require Carp; |
217 | Carp::confess("Usage: DynaLoader::bootstrap(module)"); |
218 | } |
8e07c86e |
219 | |
220 | # A common error on platforms which don't support dynamic loading. |
221 | # Since it's fatal and potentially confusing we give a detailed message. |
fb73857a |
222 | croak("Can't load module $module, dynamic loading not available in this perl.\n". |
8e07c86e |
223 | " (You may need to build a new perl executable which either supports\n". |
224 | " dynamic loading or has the $module module statically linked into it.)\n") |
225 | unless defined(&dl_load_file); |
226 | |
227 | my @modparts = split(/::/,$module); |
228 | my $modfname = $modparts[-1]; |
229 | |
230 | # Some systems have restrictions on files names for DLL's etc. |
231 | # mod2fname returns appropriate file base name (typically truncated) |
232 | # It may also edit @modparts if required. |
233 | $modfname = &mod2fname(\@modparts) if defined &mod2fname; |
234 | |
146174a9 |
235 | my $modpname = join(($Is_MacOS ? ':' : '/'),@modparts); |
8e07c86e |
236 | |
237 | print STDERR "DynaLoader::bootstrap for $module ", |
146174a9 |
238 | ($Is_MacOS |
6662521e |
239 | ? "(:auto:$modpname:$modfname.$dl_dlext)\n" : |
240 | "(auto/$modpname/$modfname.$dl_dlext)\n") |
146174a9 |
241 | if $dl_debug; |
8e07c86e |
242 | |
243 | foreach (@INC) { |
54d6a3b3 |
244 | chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS; |
146174a9 |
245 | my $dir; |
246 | if ($Is_MacOS) { |
247 | chop $_ if /:$/; |
248 | $dir = "$_:auto:$modpname"; |
249 | } else { |
250 | $dir = "$_/auto/$modpname"; |
251 | } |
8e07c86e |
252 | next unless -d $dir; # skip over uninteresting directories |
253 | |
254 | # check for common cases to avoid autoload of dl_findfile |
146174a9 |
255 | my $try = $Is_MacOS ? "$dir:$modfname.$dl_dlext" : "$dir/$modfname.$dl_dlext"; |
fb73857a |
256 | last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try); |
8e07c86e |
257 | |
258 | # no luck here, save dir for possible later dl_findfile search |
fb73857a |
259 | push @dirs, $dir; |
8e07c86e |
260 | } |
261 | # last resort, let dl_findfile have a go in all known locations |
fb73857a |
262 | $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file; |
8e07c86e |
263 | |
fb73857a |
264 | croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)") |
265 | unless $file; # wording similar to error from 'require' |
8e07c86e |
266 | |
7e9f3af8 |
267 | $file = uc($file) if $Is_VMS && $Config::Config{d_vms_case_sensitive_symbols}; |
8e07c86e |
268 | my $bootname = "boot_$module"; |
269 | $bootname =~ s/\W/_/g; |
270 | @dl_require_symbols = ($bootname); |
271 | |
272 | # Execute optional '.bootstrap' perl script for this module. |
273 | # The .bs file can be used to configure @dl_resolve_using etc to |
274 | # match the needs of the individual module on this architecture. |
275 | my $bs = $file; |
3f45a6dd |
276 | $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library |
8e07c86e |
277 | if (-s $bs) { # only read file if it's not empty |
d404d5bf |
278 | print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug; |
8e07c86e |
279 | eval { do $bs; }; |
280 | warn "$bs: $@\n" if $@; |
281 | } |
282 | |
283 | # Many dynamic extension loading problems will appear to come from |
284 | # this section of code: XYZ failed at line 123 of DynaLoader.pm. |
285 | # Often these errors are actually occurring in the initialisation |
286 | # C code of the extension XS file. Perl reports the error as being |
287 | # in this perl code simply because this was the last perl code |
288 | # it executed. |
289 | |
ff7f3c60 |
290 | my $libref = dl_load_file($file, $module->dl_load_flags) or |
549a6b10 |
291 | croak("Can't load '$file' for module $module: ".dl_error()); |
8e07c86e |
292 | |
ff7f3c60 |
293 | push(@dl_librefs,$libref); # record loaded object |
294 | |
8e07c86e |
295 | my @unresolved = dl_undef_symbols(); |
fb73857a |
296 | if (@unresolved) { |
297 | require Carp; |
298 | Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); |
299 | } |
8e07c86e |
300 | |
301 | my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or |
fb73857a |
302 | croak("Can't find '$bootname' symbol in $file\n"); |
8e07c86e |
303 | |
304 | my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file); |
305 | |
ff7f3c60 |
306 | push(@dl_modules, $module); # record loaded module |
307 | |
8e07c86e |
308 | # See comment block above |
309 | &$xs(@args); |
310 | } |
311 | |
312 | |
fb73857a |
313 | #sub _check_file { # private utility to handle dl_expandspec vs -f tests |
314 | # my($file) = @_; |
315 | # return $file if (!$do_expand && -f $file); # the common case |
316 | # return $file if ( $do_expand && ($file=dl_expandspec($file))); |
317 | # return undef; |
318 | #} |
8e07c86e |
319 | |
320 | |
321 | # Let autosplit and the autoloader deal with these functions: |
322 | __END__ |
323 | |
324 | |
325 | sub dl_findfile { |
326 | # Read ext/DynaLoader/DynaLoader.doc for detailed information. |
327 | # This function does not automatically consider the architecture |
328 | # or the perl library auto directories. |
329 | my (@args) = @_; |
330 | my (@dirs, $dir); # which directories to search |
331 | my (@found); # full paths to real files we have found |
03c9e98c |
332 | EOT |
333 | |
334 | print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) . |
335 | "; # \$Config::Config{'dlext'} suffix for perl extensions\n"; |
336 | print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) . |
337 | "; # \$Config::Config{'so'} suffix for shared libraries\n"; |
338 | |
339 | print OUT <<'EOT'; |
8e07c86e |
340 | |
341 | print STDERR "dl_findfile(@args)\n" if $dl_debug; |
342 | |
343 | # accumulate directories but process files as they appear |
344 | arg: foreach(@args) { |
345 | # Special fast case: full filepath requires no search |
54d6a3b3 |
346 | if ($Is_VMS && m%[:>/\]]% && -f $_) { |
347 | push(@found,dl_expandspec(VMS::Filespec::vmsify($_))); |
348 | last arg unless wantarray; |
349 | next; |
350 | } |
146174a9 |
351 | elsif ($Is_MacOS) { |
352 | if (m/:/ && -f $_) { |
353 | push(@found,$_); |
354 | last arg unless wantarray; |
355 | } |
356 | } |
54d6a3b3 |
357 | elsif (m:/: && -f $_ && !$do_expand) { |
8e07c86e |
358 | push(@found,$_); |
359 | last arg unless wantarray; |
360 | next; |
361 | } |
362 | |
363 | # Deal with directories first: |
364 | # Using a -L prefix is the preferred option (faster and more robust) |
365 | if (m:^-L:) { s/^-L//; push(@dirs, $_); next; } |
366 | |
146174a9 |
367 | if ($Is_MacOS) { |
368 | # Otherwise we try to try to spot directories by a heuristic |
369 | # (this is a more complicated issue than it first appears) |
370 | if (m/:/ && -d $_) { push(@dirs, $_); next; } |
371 | # Only files should get this far... |
372 | my(@names, $name); # what filenames to look for |
373 | s/^-l//; |
374 | push(@names, $_); |
375 | foreach $dir (@dirs, @dl_library_path) { |
376 | next unless -d $dir; |
377 | $dir =~ s/^([^:]+)$/:$1/; |
378 | $dir =~ s/:$//; |
379 | foreach $name (@names) { |
380 | my($file) = "$dir:$name"; |
381 | print STDERR " checking in $dir for $name\n" if $dl_debug; |
382 | if (-f $file) { |
383 | push(@found, $file); |
384 | next arg; # no need to look any further |
385 | } |
386 | } |
387 | } |
388 | next; |
389 | } |
390 | |
8e07c86e |
391 | # Otherwise we try to try to spot directories by a heuristic |
392 | # (this is a more complicated issue than it first appears) |
393 | if (m:/: && -d $_) { push(@dirs, $_); next; } |
394 | |
7e9f3af8 |
395 | # VMS: we may be using native VMS directory syntax instead of |
8e07c86e |
396 | # Unix emulation, so check this as well |
54d6a3b3 |
397 | if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; } |
8e07c86e |
398 | |
399 | # Only files should get this far... |
400 | my(@names, $name); # what filenames to look for |
401 | if (m:-l: ) { # convert -lname to appropriate library name |
402 | s/-l//; |
403 | push(@names,"lib$_.$dl_so"); |
404 | push(@names,"lib$_.a"); |
405 | } else { # Umm, a bare name. Try various alternatives: |
406 | # these should be ordered with the most likely first |
d404d5bf |
407 | push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o; |
8e07c86e |
408 | push(@names,"$_.$dl_so") unless m/\.$dl_so$/o; |
409 | push(@names,"lib$_.$dl_so") unless m:/:; |
8e07c86e |
410 | push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs"; |
411 | push(@names, $_); |
412 | } |
413 | foreach $dir (@dirs, @dl_library_path) { |
414 | next unless -d $dir; |
54d6a3b3 |
415 | chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS; |
8e07c86e |
416 | foreach $name (@names) { |
417 | my($file) = "$dir/$name"; |
418 | print STDERR " checking in $dir for $name\n" if $dl_debug; |
fb73857a |
419 | $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file); |
420 | #$file = _check_file($file); |
8e07c86e |
421 | if ($file) { |
422 | push(@found, $file); |
423 | next arg; # no need to look any further |
424 | } |
425 | } |
426 | } |
427 | } |
428 | if ($dl_debug) { |
429 | foreach(@dirs) { |
430 | print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_; |
431 | } |
432 | print STDERR "dl_findfile found: @found\n"; |
433 | } |
434 | return $found[0] unless wantarray; |
435 | @found; |
436 | } |
437 | |
438 | |
439 | sub dl_expandspec { |
440 | my($spec) = @_; |
441 | # Optional function invoked if DynaLoader.pm sets $do_expand. |
442 | # Most systems do not require or use this function. |
443 | # Some systems may implement it in the dl_*.xs file in which case |
444 | # this autoload version will not be called but is harmless. |
445 | |
446 | # This function is designed to deal with systems which treat some |
447 | # 'filenames' in a special way. For example VMS 'Logical Names' |
448 | # (something like unix environment variables - but different). |
449 | # This function should recognise such names and expand them into |
450 | # full file paths. |
451 | # Must return undef if $spec is invalid or file does not exist. |
452 | |
453 | my $file = $spec; # default output to input |
454 | |
d404d5bf |
455 | if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs |
fb73857a |
456 | require Carp; |
4633a7c4 |
457 | Carp::croak("dl_expandspec: should be defined in XS file!\n"); |
8e07c86e |
458 | } else { |
459 | return undef unless -f $file; |
460 | } |
461 | print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug; |
462 | $file; |
463 | } |
464 | |
ff7f3c60 |
465 | sub dl_find_symbol_anywhere |
466 | { |
467 | my $sym = shift; |
468 | my $libref; |
469 | foreach $libref (@dl_librefs) { |
470 | my $symref = dl_find_symbol($libref,$sym); |
471 | return $symref if $symref; |
472 | } |
473 | return undef; |
474 | } |
8e07c86e |
475 | |
3b35bae3 |
476 | =head1 NAME |
477 | |
478 | DynaLoader - Dynamically load C libraries into Perl code |
479 | |
abb9e9dc |
480 | dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_unload_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules |
3b35bae3 |
481 | |
482 | =head1 SYNOPSIS |
483 | |
8e07c86e |
484 | package YourPackage; |
3b35bae3 |
485 | require DynaLoader; |
c2960299 |
486 | @ISA = qw(... DynaLoader ...); |
8e07c86e |
487 | bootstrap YourPackage; |
3b35bae3 |
488 | |
ff7f3c60 |
489 | # optional method for 'global' loading |
490 | sub dl_load_flags { 0x01 } |
491 | |
3b35bae3 |
492 | |
493 | =head1 DESCRIPTION |
494 | |
c2960299 |
495 | This document defines a standard generic interface to the dynamic |
3b35bae3 |
496 | linking mechanisms available on many platforms. Its primary purpose is |
497 | to implement automatic dynamic loading of Perl modules. |
498 | |
c2960299 |
499 | This document serves as both a specification for anyone wishing to |
500 | implement the DynaLoader for a new platform and as a guide for |
501 | anyone wishing to use the DynaLoader directly in an application. |
502 | |
3b35bae3 |
503 | The DynaLoader is designed to be a very simple high-level |
504 | interface that is sufficiently general to cover the requirements |
505 | of SunOS, HP-UX, NeXT, Linux, VMS and other platforms. |
506 | |
c2960299 |
507 | It is also hoped that the interface will cover the needs of OS/2, NT |
508 | etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime). |
3b35bae3 |
509 | |
510 | It must be stressed that the DynaLoader, by itself, is practically |
511 | useless for accessing non-Perl libraries because it provides almost no |
512 | Perl-to-C 'glue'. There is, for example, no mechanism for calling a C |
03c9e98c |
513 | library function or supplying arguments. A C::DynaLib module |
90248788 |
514 | is available from CPAN sites which performs that function for some |
515 | common system types. |
3b35bae3 |
516 | |
517 | DynaLoader Interface Summary |
518 | |
519 | @dl_library_path |
520 | @dl_resolve_using |
521 | @dl_require_symbols |
522 | $dl_debug |
ff7f3c60 |
523 | @dl_librefs |
524 | @dl_modules |
3b35bae3 |
525 | Implemented in: |
526 | bootstrap($modulename) Perl |
527 | @filepaths = dl_findfile(@names) Perl |
ff7f3c60 |
528 | $flags = $modulename->dl_load_flags Perl |
529 | $symref = dl_find_symbol_anywhere($symbol) Perl |
3b35bae3 |
530 | |
ff7f3c60 |
531 | $libref = dl_load_file($filename, $flags) C |
abb9e9dc |
532 | $status = dl_unload_file($libref) C |
3b35bae3 |
533 | $symref = dl_find_symbol($libref, $symbol) C |
534 | @symbols = dl_undef_symbols() C |
535 | dl_install_xsub($name, $symref [, $filename]) C |
536 | $message = dl_error C |
537 | |
538 | =over 4 |
539 | |
540 | =item @dl_library_path |
541 | |
542 | The standard/default list of directories in which dl_findfile() will |
543 | search for libraries etc. Directories are searched in order: |
544 | $dl_library_path[0], [1], ... etc |
545 | |
546 | @dl_library_path is initialised to hold the list of 'normal' directories |
547 | (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should |
548 | ensure portability across a wide range of platforms. |
549 | |
550 | @dl_library_path should also be initialised with any other directories |
551 | that can be determined from the environment at runtime (such as |
552 | LD_LIBRARY_PATH for SunOS). |
553 | |
554 | After initialisation @dl_library_path can be manipulated by an |
555 | application using push and unshift before calling dl_findfile(). |
556 | Unshift can be used to add directories to the front of the search order |
557 | either to save search time or to override libraries with the same name |
558 | in the 'normal' directories. |
559 | |
560 | The load function that dl_load_file() calls may require an absolute |
561 | pathname. The dl_findfile() function and @dl_library_path can be |
562 | used to search for and return the absolute pathname for the |
563 | library/object that you wish to load. |
564 | |
565 | =item @dl_resolve_using |
566 | |
567 | A list of additional libraries or other shared objects which can be |
568 | used to resolve any undefined symbols that might be generated by a |
569 | later call to load_file(). |
570 | |
571 | This is only required on some platforms which do not handle dependent |
7a2e2cd6 |
572 | libraries automatically. For example the Socket Perl extension |
573 | library (F<auto/Socket/Socket.so>) contains references to many socket |
574 | functions which need to be resolved when it's loaded. Most platforms |
575 | will automatically know where to find the 'dependent' library (e.g., |
576 | F</usr/lib/libsocket.so>). A few platforms need to be told the |
577 | location of the dependent library explicitly. Use @dl_resolve_using |
578 | for this. |
3b35bae3 |
579 | |
580 | Example usage: |
581 | |
582 | @dl_resolve_using = dl_findfile('-lsocket'); |
583 | |
584 | =item @dl_require_symbols |
585 | |
586 | A list of one or more symbol names that are in the library/object file |
587 | to be dynamically loaded. This is only required on some platforms. |
588 | |
ff7f3c60 |
589 | =item @dl_librefs |
590 | |
591 | An array of the handles returned by successful calls to dl_load_file(), |
592 | made by bootstrap, in the order in which they were loaded. |
593 | Can be used with dl_find_symbol() to look for a symbol in any of |
594 | the loaded files. |
595 | |
596 | =item @dl_modules |
597 | |
598 | An array of module (package) names that have been bootstrap'ed. |
599 | |
3b35bae3 |
600 | =item dl_error() |
601 | |
602 | Syntax: |
603 | |
604 | $message = dl_error(); |
605 | |
606 | Error message text from the last failed DynaLoader function. Note |
607 | that, similar to errno in unix, a successful function call does not |
608 | reset this message. |
609 | |
610 | Implementations should detect the error as soon as it occurs in any of |
611 | the other functions and save the corresponding message for later |
612 | retrieval. This will avoid problems on some platforms (such as SunOS) |
613 | where the error message is very temporary (e.g., dlerror()). |
614 | |
615 | =item $dl_debug |
616 | |
617 | Internal debugging messages are enabled when $dl_debug is set true. |
618 | Currently setting $dl_debug only affects the Perl side of the |
619 | DynaLoader. These messages should help an application developer to |
620 | resolve any DynaLoader usage problems. |
621 | |
622 | $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined. |
623 | |
624 | For the DynaLoader developer/porter there is a similar debugging |
625 | variable added to the C code (see dlutils.c) and enabled if Perl was |
626 | built with the B<-DDEBUGGING> flag. This can also be set via the |
627 | PERL_DL_DEBUG environment variable. Set to 1 for minimal information or |
628 | higher for more. |
629 | |
630 | =item dl_findfile() |
631 | |
632 | Syntax: |
633 | |
634 | @filepaths = dl_findfile(@names) |
635 | |
636 | Determine the full paths (including file suffix) of one or more |
637 | loadable files given their generic names and optionally one or more |
638 | directories. Searches directories in @dl_library_path by default and |
639 | returns an empty list if no files were found. |
640 | |
641 | Names can be specified in a variety of platform independent forms. Any |
642 | names in the form B<-lname> are converted into F<libname.*>, where F<.*> is |
643 | an appropriate suffix for the platform. |
644 | |
645 | If a name does not already have a suitable prefix and/or suffix then |
646 | the corresponding file will be searched for by trying combinations of |
647 | prefix and suffix appropriate to the platform: "$name.o", "lib$name.*" |
648 | and "$name". |
649 | |
650 | If any directories are included in @names they are searched before |
c2960299 |
651 | @dl_library_path. Directories may be specified as B<-Ldir>. Any other |
652 | names are treated as filenames to be searched for. |
3b35bae3 |
653 | |
654 | Using arguments of the form C<-Ldir> and C<-lname> is recommended. |
655 | |
656 | Example: |
657 | |
658 | @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix)); |
659 | |
660 | |
661 | =item dl_expandspec() |
662 | |
663 | Syntax: |
664 | |
665 | $filepath = dl_expandspec($spec) |
666 | |
667 | Some unusual systems, such as VMS, require special filename handling in |
668 | order to deal with symbolic names for files (i.e., VMS's Logical Names). |
669 | |
670 | To support these systems a dl_expandspec() function can be implemented |
671 | either in the F<dl_*.xs> file or code can be added to the autoloadable |
c2960299 |
672 | dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for |
673 | more information. |
3b35bae3 |
674 | |
675 | =item dl_load_file() |
676 | |
677 | Syntax: |
678 | |
ff7f3c60 |
679 | $libref = dl_load_file($filename, $flags) |
3b35bae3 |
680 | |
681 | Dynamically load $filename, which must be the path to a shared object |
682 | or library. An opaque 'library reference' is returned as a handle for |
683 | the loaded object. Returns undef on error. |
684 | |
ff7f3c60 |
685 | The $flags argument to alters dl_load_file behaviour. |
686 | Assigned bits: |
687 | |
688 | 0x01 make symbols available for linking later dl_load_file's. |
689 | (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) |
f86702cc |
690 | (ignored under VMS; this is a normal part of image linking) |
ff7f3c60 |
691 | |
3b35bae3 |
692 | (On systems that provide a handle for the loaded object such as SunOS |
693 | and HPUX, $libref will be that handle. On other systems $libref will |
694 | typically be $filename or a pointer to a buffer containing $filename. |
695 | The application should not examine or alter $libref in any way.) |
696 | |
ff7f3c60 |
697 | This is the function that does the real work. It should use the |
698 | current values of @dl_require_symbols and @dl_resolve_using if required. |
3b35bae3 |
699 | |
700 | SunOS: dlopen($filename) |
701 | HP-UX: shl_load($filename) |
702 | Linux: dld_create_reference(@dl_require_symbols); dld_link($filename) |
703 | NeXT: rld_load($filename, @dl_resolve_using) |
704 | VMS: lib$find_image_symbol($filename,$dl_require_symbols[0]) |
705 | |
ff7f3c60 |
706 | (The dlopen() function is also used by Solaris and some versions of |
707 | Linux, and is a common choice when providing a "wrapper" on other |
708 | mechanisms as is done in the OS/2 port.) |
709 | |
abb9e9dc |
710 | =item dl_unload_file() |
711 | |
712 | Syntax: |
713 | |
714 | $status = dl_unload_file($libref) |
715 | |
716 | Dynamically unload $libref, which must be an opaque 'library reference' as |
717 | returned from dl_load_file. Returns one on success and zero on failure. |
718 | |
719 | This function is optional and may not necessarily be provided on all platforms. |
720 | If it is defined, it is called automatically when the interpreter exits for |
721 | every shared object or library loaded by DynaLoader::bootstrap. All such |
722 | library references are stored in @dl_librefs by DynaLoader::Bootstrap as it |
22851543 |
723 | loads the libraries. The files are unloaded in last-in, first-out order. |
abb9e9dc |
724 | |
725 | This unloading is usually necessary when embedding a shared-object perl (e.g. |
726 | one configured with -Duseshrplib) within a larger application, and the perl |
727 | interpreter is created and destroyed several times within the lifetime of the |
728 | application. In this case it is possible that the system dynamic linker will |
729 | unload and then subsequently reload the shared libperl without relocating any |
730 | references to it from any files DynaLoaded by the previous incarnation of the |
731 | interpreter. As a result, any shared objects opened by DynaLoader may point to |
732 | a now invalid 'ghost' of the libperl shared object, causing apparently random |
733 | memory corruption and crashes. This behaviour is most commonly seen when using |
734 | Apache and mod_perl built with the APXS mechanism. |
735 | |
736 | SunOS: dlclose($libref) |
737 | HP-UX: ??? |
738 | Linux: ??? |
739 | NeXT: ??? |
740 | VMS: ??? |
741 | |
742 | (The dlclose() function is also used by Solaris and some versions of |
743 | Linux, and is a common choice when providing a "wrapper" on other |
744 | mechanisms as is done in the OS/2 port.) |
745 | |
ff7f3c60 |
746 | =item dl_loadflags() |
747 | |
748 | Syntax: |
749 | |
750 | $flags = dl_loadflags $modulename; |
751 | |
752 | Designed to be a method call, and to be overridden by a derived class |
753 | (i.e. a class which has DynaLoader in its @ISA). The definition in |
754 | DynaLoader itself returns 0, which produces standard behavior from |
755 | dl_load_file(). |
3b35bae3 |
756 | |
757 | =item dl_find_symbol() |
758 | |
759 | Syntax: |
760 | |
761 | $symref = dl_find_symbol($libref, $symbol) |
762 | |
763 | Return the address of the symbol $symbol or C<undef> if not found. If the |
764 | target system has separate functions to search for symbols of different |
765 | types then dl_find_symbol() should search for function symbols first and |
766 | then other types. |
767 | |
768 | The exact manner in which the address is returned in $symref is not |
769 | currently defined. The only initial requirement is that $symref can |
770 | be passed to, and understood by, dl_install_xsub(). |
771 | |
772 | SunOS: dlsym($libref, $symbol) |
773 | HP-UX: shl_findsym($libref, $symbol) |
774 | Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol) |
775 | NeXT: rld_lookup("_$symbol") |
776 | VMS: lib$find_image_symbol($libref,$symbol) |
777 | |
778 | |
ff7f3c60 |
779 | =item dl_find_symbol_anywhere() |
780 | |
781 | Syntax: |
782 | |
783 | $symref = dl_find_symbol_anywhere($symbol) |
784 | |
785 | Applies dl_find_symbol() to the members of @dl_librefs and returns |
786 | the first match found. |
787 | |
3b35bae3 |
788 | =item dl_undef_symbols() |
789 | |
790 | Example |
791 | |
792 | @symbols = dl_undef_symbols() |
793 | |
794 | Return a list of symbol names which remain undefined after load_file(). |
795 | Returns C<()> if not known. Don't worry if your platform does not provide |
c2960299 |
796 | a mechanism for this. Most do not need it and hence do not provide it, |
797 | they just return an empty list. |
3b35bae3 |
798 | |
799 | |
800 | =item dl_install_xsub() |
801 | |
802 | Syntax: |
803 | |
804 | dl_install_xsub($perl_name, $symref [, $filename]) |
805 | |
806 | Create a new Perl external subroutine named $perl_name using $symref as |
807 | a pointer to the function which implements the routine. This is simply |
808 | a direct call to newXSUB(). Returns a reference to the installed |
809 | function. |
810 | |
811 | The $filename parameter is used by Perl to identify the source file for |
812 | the function if required by die(), caller() or the debugger. If |
813 | $filename is not defined then "DynaLoader" will be used. |
814 | |
815 | |
1fef88e7 |
816 | =item bootstrap() |
3b35bae3 |
817 | |
818 | Syntax: |
819 | |
820 | bootstrap($module) |
821 | |
822 | This is the normal entry point for automatic dynamic loading in Perl. |
823 | |
824 | It performs the following actions: |
825 | |
826 | =over 8 |
827 | |
828 | =item * |
829 | |
830 | locates an auto/$module directory by searching @INC |
831 | |
832 | =item * |
833 | |
834 | uses dl_findfile() to determine the filename to load |
835 | |
836 | =item * |
837 | |
838 | sets @dl_require_symbols to C<("boot_$module")> |
839 | |
840 | =item * |
841 | |
842 | executes an F<auto/$module/$module.bs> file if it exists |
843 | (typically used to add to @dl_resolve_using any files which |
844 | are required to load the module on the current platform) |
845 | |
846 | =item * |
847 | |
ff7f3c60 |
848 | calls dl_load_flags() to determine how to load the file. |
849 | |
850 | =item * |
851 | |
3b35bae3 |
852 | calls dl_load_file() to load the file |
853 | |
854 | =item * |
855 | |
856 | calls dl_undef_symbols() and warns if any symbols are undefined |
857 | |
858 | =item * |
859 | |
860 | calls dl_find_symbol() for "boot_$module" |
861 | |
862 | =item * |
863 | |
864 | calls dl_install_xsub() to install it as "${module}::bootstrap" |
865 | |
866 | =item * |
867 | |
8e07c86e |
868 | calls &{"${module}::bootstrap"} to bootstrap the module (actually |
869 | it uses the function reference returned by dl_install_xsub for speed) |
3b35bae3 |
870 | |
871 | =back |
872 | |
873 | =back |
874 | |
875 | |
876 | =head1 AUTHOR |
877 | |
c2960299 |
878 | Tim Bunce, 11 August 1994. |
879 | |
3b35bae3 |
880 | This interface is based on the work and comments of (in no particular |
881 | order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno |
c2960299 |
882 | Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others. |
3b35bae3 |
883 | |
884 | Larry Wall designed the elegant inherited bootstrap mechanism and |
885 | implemented the first Perl 5 dynamic loader using it. |
886 | |
ff7f3c60 |
887 | Solaris global loading added by Nick Ing-Simmons with design/coding |
888 | assistance from Tim Bunce, January 1996. |
889 | |
3b35bae3 |
890 | =cut |
03c9e98c |
891 | EOT |
892 | |
893 | close OUT or die $!; |
894 | |