Commit | Line | Data |
---|---|---|
03c9e98c GS |
1 | use Config; |
2 | ||
3 | sub to_string { | |
4 | my ($value) = @_; | |
146174a9 | 5 | $value =~ s/\\/\\\\/g; |
03c9e98c GS |
6 | $value =~ s/'/\\'/g; |
7 | return "'$value'"; | |
8 | } | |
9 | ||
10 | unlink "DynaLoader.pm" if -f "DynaLoader.pm"; | |
11 | open OUT, ">DynaLoader.pm" or die $!; | |
12 | print OUT <<'EOT'; | |
13 | ||
d0a5ed9f | 14 | # Generated from DynaLoader.pm.PL |
03c9e98c | 15 | |
a0d0e21e LW |
16 | package DynaLoader; |
17 | ||
8e07c86e AD |
18 | # And Gandalf said: 'Many folk like to know beforehand what is to |
19 | # be set on the table; but those who have laboured to prepare the | |
20 | # feast like to keep their secret; for wonder makes the words of | |
21 | # praise louder.' | |
22 | ||
6662521e | 23 | # (Quote from Tolkien suggested by Anno Siegel.) |
8e07c86e AD |
24 | # |
25 | # See pod text at end of file for documentation. | |
26 | # See also ext/DynaLoader/README in source tree for other information. | |
27 | # | |
28 | # Tim.Bunce@ig.co.uk, August 1994 | |
29 | ||
632a9a7f A |
30 | use vars qw($VERSION *AUTOLOAD); |
31 | ||
32 | $VERSION = 1.04; # avoid typo warning | |
dc848c6f | 33 | |
dc848c6f | 34 | require AutoLoader; |
35 | *AUTOLOAD = \&AutoLoader::AUTOLOAD; | |
8e07c86e | 36 | |
7e9f3af8 JH |
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 AD |
46 | # enable debug/trace messages from DynaLoader perl code |
47 | $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug; | |
48 | ||
ff7f3c60 NIS |
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 NIS |
54 | # |
55 | # This is called as a class method $module->dl_load_flags. The | |
56 | # definition here will be inherited and result on "default" loading | |
57 | # behaviour unless a sub-class of DynaLoader defines its own version. | |
58 | # | |
59 | ||
60 | sub dl_load_flags { 0x00 } | |
61 | ||
03c9e98c GS |
62 | # ($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 AD |
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 A |
76 | $Is_VMS = $^O eq 'VMS'; |
77 | $do_expand = $Is_VMS; | |
78 | $Is_MacOS = $^O eq 'MacOS'; | |
8e07c86e AD |
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 A |
83 | @dl_librefs = (); # things we have loaded |
84 | @dl_modules = (); # Modules we have loaded | |
8e07c86e AD |
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(' ', $Config::Config{libpth})); |
03c9e98c GS |
93 | EOT |
94 | ||
d0a5ed9f JH |
95 | sub dquoted_comma_list { |
96 | join(", ", map {qq("$_")} @_); | |
97 | } | |
03c9e98c | 98 | |
d0a5ed9f JH |
99 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) { |
100 | eval $cfg_dl_library_path; | |
101 | if (!$ENV{PERL_BUILD_EXPAND_ENV_VARS}) { | |
102 | my $dl_library_path = dquoted_comma_list(@dl_library_path); | |
103 | print OUT <<EOT; | |
7e9f3af8 | 104 | # The below \@dl_library_path has been expanded (%Config) in Perl build time. |
d0a5ed9f JH |
105 | |
106 | \@dl_library_path = ($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 JH |
123 | my $pthsep; |
124 | ||
125 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) { | |
7e9f3af8 JH |
126 | $ldlibpthname = $Config::Config{ldlibpthname}; |
127 | $ldlibpthname_defined = defined $Config::Config{ldlibpthname} ? 1 : 0; | |
128 | $pthsep = $Config::Config{path_sep}; | |
8225e35f JH |
129 | } |
130 | else { | |
7e9f3af8 JH |
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 JH |
135 | my \$ldlibpthname = $ldlibpthname; |
136 | my \$ldlibpthname_defined = $ldlibpthname_defined; | |
137 | my \$pthsep = $pthsep; | |
8225e35f JH |
138 | |
139 | EOT | |
140 | } | |
141 | ||
7e9f3af8 JH |
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 JH |
146 | } |
147 | ||
5cf1d1f1 | 148 | # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH. |
8225e35f | 149 | |
7e9f3af8 JH |
150 | if ($ldlibpthname_defined && |
151 | $ldlibpthname ne 'LD_LIBRARY_PATH' && | |
152 | exists $ENV{LD_LIBRARY_PATH}) { | |
153 | push(@dl_library_path, split(/$pthsep/, $ENV{LD_LIBRARY_PATH})); | |
d0a5ed9f | 154 | } |
e6197cab NC |
155 | EOT |
156 | ||
d0a5ed9f JH |
157 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS} && $ENV{PERL_BUILD_EXPAND_ENV_VARS}) { |
158 | eval $env_dl_library_path; | |
e6197cab | 159 | } |
d0a5ed9f JH |
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 JH |
165 | $env_dl_library_path |
166 | ||
167 | EOT | |
e6197cab NC |
168 | } |
169 | ||
d0a5ed9f JH |
170 | if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS} && $ENV{PERL_BUILD_EXPAND_ENV_VARS}) { |
171 | my $dl_library_path = dquoted_comma_list(@dl_library_path); | |
172 | print OUT <<EOT; | |
7e9f3af8 JH |
173 | # The below \@dl_library_path has been expanded (%Config, %ENV) |
174 | # in Perl build time. | |
d0a5ed9f JH |
175 | |
176 | \@dl_library_path = ($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 AD |
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 CB |
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 AD |
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 AD |
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 AD |
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 AD |
236 | |
237 | print STDERR "DynaLoader::bootstrap for $module ", | |
146174a9 | 238 | ($Is_MacOS |
6662521e GS |
239 | ? "(:auto:$modpname:$modfname.$dl_dlext)\n" : |
240 | "(auto/$modpname/$modfname.$dl_dlext)\n") | |
146174a9 | 241 | if $dl_debug; |
8e07c86e AD |
242 | |
243 | foreach (@INC) { | |
54d6a3b3 | 244 | chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS; |
146174a9 CB |
245 | my $dir; |
246 | if ($Is_MacOS) { | |
247 | chop $_ if /:$/; | |
248 | $dir = "$_:auto:$modpname"; | |
249 | } else { | |
250 | $dir = "$_/auto/$modpname"; | |
251 | } | |
8e07c86e AD |
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 AD |
257 | |
258 | # no luck here, save dir for possible later dl_findfile search | |
fb73857a | 259 | push @dirs, $dir; |
8e07c86e AD |
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 AD |
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 AD |
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 $module: ".dl_error()); |
8e07c86e | 292 | |
ff7f3c60 NIS |
293 | push(@dl_librefs,$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 AD |
300 | |
301 | my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or | |
fb73857a | 302 | croak("Can't find '$bootname' symbol in $file\n"); |
8e07c86e AD |
303 | |
304 | my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file); | |
305 | ||
ff7f3c60 NIS |
306 | push(@dl_modules, $module); # record loaded module |
307 | ||
8e07c86e AD |
308 | # See comment block above |
309 | &$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 AD |
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 GS |
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 AD |
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 CB |
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 AD |
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, $_); next; } | |
366 | ||
146174a9 CB |
367 | if ($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 AD |
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 AD |
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 AD |
408 | push(@names,"$_.$dl_so") unless m/\.$dl_so$/o; |
409 | push(@names,"lib$_.$dl_so") unless m:/:; | |
8e07c86e AD |
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 AD |
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($file); | |
8e07c86e AD |
421 | if ($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 AD |
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 NIS |
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 AD |
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 AD |
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 NIS |
489 | # optional method for 'global' loading |
490 | sub dl_load_flags { 0x01 } | |
491 | ||
3b35bae3 AD |
492 | |
493 | =head1 DESCRIPTION | |
494 | ||
c2960299 | 495 | This document defines a standard generic interface to the dynamic |
3b35bae3 AD |
496 | linking mechanisms available on many platforms. Its primary purpose is |
497 | to implement automatic dynamic loading of Perl modules. | |
498 | ||
c2960299 AD |
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 AD |
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 AD |
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 AD |
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 TB |
514 | is available from CPAN sites which performs that function for some |
515 | common system types. | |
3b35bae3 AD |
516 | |
517 | DynaLoader Interface Summary | |
518 | ||
519 | @dl_library_path | |
520 | @dl_resolve_using | |
521 | @dl_require_symbols | |
522 | $dl_debug | |
ff7f3c60 NIS |
523 | @dl_librefs |
524 | @dl_modules | |
3b35bae3 AD |
525 | Implemented in: |
526 | bootstrap($modulename) Perl | |
527 | @filepaths = dl_findfile(@names) Perl | |
ff7f3c60 NIS |
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 AD |
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 AD |
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 NIS |
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 AD |
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 AD |
651 | @dl_library_path. Directories may be specified as B<-Ldir>. Any other |
652 | names are treated as filenames to be searched for. | |
3b35bae3 AD |
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 AD |
672 | dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for |
673 | more information. | |
3b35bae3 AD |
674 | |
675 | =item dl_load_file() | |
676 | ||
677 | Syntax: | |
678 | ||
ff7f3c60 | 679 | $libref = dl_load_file($filename, $flags) |
3b35bae3 AD |
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 NIS |
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 AD |
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 $libref in any way.) | |
696 | ||
ff7f3c60 NIS |
697 | This is the function that does the real work. It should use the |
698 | current values of @dl_require_symbols and @dl_resolve_using if required. | |
3b35bae3 AD |
699 | |
700 | SunOS: dlopen($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 NIS |
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 GS |
710 | =item dl_unload_file() |
711 | ||
712 | Syntax: | |
713 | ||
714 | $status = dl_unload_file($libref) | |
715 | ||
716 | Dynamically unload $libref, which must be an opaque 'library reference' as | |
717 | returned from dl_load_file. Returns one on success and zero on failure. | |
718 | ||
719 | This function is optional and may not necessarily be provided on all platforms. | |
720 | If it is defined, it is called automatically when the interpreter exits for | |
721 | every shared object or library loaded by DynaLoader::bootstrap. All such | |
722 | library references are stored in @dl_librefs by DynaLoader::Bootstrap as it | |
22851543 | 723 | loads the libraries. The files are unloaded in last-in, first-out order. |
abb9e9dc GS |
724 | |
725 | This unloading is usually necessary when embedding a shared-object perl (e.g. | |
726 | one configured with -Duseshrplib) within a larger application, and the perl | |
727 | interpreter is created and destroyed several times within the lifetime of the | |
728 | application. In this case it is possible that the system dynamic linker will | |
729 | unload and then subsequently reload the shared libperl without relocating any | |
730 | references to it from any files DynaLoaded by the previous incarnation of the | |
731 | interpreter. As a result, any shared objects opened by DynaLoader may point to | |
732 | a now invalid 'ghost' of the libperl shared object, causing apparently random | |
733 | memory corruption and crashes. This behaviour is most commonly seen when using | |
734 | Apache and mod_perl built with the APXS mechanism. | |
735 | ||
736 | SunOS: dlclose($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 NIS |
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 AD |
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 NIS |
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 AD |
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 AD |
796 | a mechanism for this. Most do not need it and hence do not provide it, |
797 | they just return an empty list. | |
3b35bae3 AD |
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 | $filename is not defined then "DynaLoader" will be used. | |
814 | ||
815 | ||
1fef88e7 | 816 | =item bootstrap() |
3b35bae3 AD |
817 | |
818 | Syntax: | |
819 | ||
820 | bootstrap($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 NIS |
848 | calls dl_load_flags() to determine how to load the file. |
849 | ||
850 | =item * | |
851 | ||
3b35bae3 AD |
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 AD |
868 | calls &{"${module}::bootstrap"} to bootstrap the module (actually |
869 | it uses the function reference returned by dl_install_xsub for speed) | |
3b35bae3 AD |
870 | |
871 | =back | |
872 | ||
873 | =back | |
874 | ||
875 | ||
876 | =head1 AUTHOR | |
877 | ||
c2960299 AD |
878 | Tim Bunce, 11 August 1994. |
879 | ||
3b35bae3 AD |
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 AD |
883 | |
884 | Larry Wall designed the elegant inherited bootstrap mechanism and | |
885 | implemented the first Perl 5 dynamic loader using it. | |
886 | ||
ff7f3c60 NIS |
887 | Solaris global loading added by Nick Ing-Simmons with design/coding |
888 | assistance from Tim Bunce, January 1996. | |
889 | ||
3b35bae3 | 890 | =cut |
03c9e98c GS |
891 | EOT |
892 | ||
893 | close OUT or die $!; | |
894 |