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This commit is contained in:
Thomas Tanner
parent
510d65627b
commit
94cfa949e2
27
ChangeLog
27
ChangeLog
@ -1,3 +1,28 @@
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1999-01-13 Thomas Tanner <tanner@gmx.de>
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* demo/dlmain.c, libltdl/ltdl.c, ltconfig.in, ltmain.in,
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doc/libtool.texi: renamed dld_preloaded_symbols to
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lt_preloaded_symbols, symbol lists are 'const'
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* cdemo/configure.in: don't check for string.h
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* demo/dlmain.c: renamed dld_symlist to lt_symlist,
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preloaded symbols are 'const', use lt_ptr_t instead of void*
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* demo/foo.h: define lt_ptr_t
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* doc/libtool.texi: document lt_preloaded_symbols correctly
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* libltdl/Makefile.am, mdemo/Makefile.am: renamed libtest to libltdlc
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* libltdl/ltdl.c: fixed some minor typos, renamed dldpre to presym,
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bugfix: search in search_path only if we have no directory
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and a search_path, in lt_dlsym() check whether symbol != 0
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* libltdl/ltdl.h: removed lt_dlpreopen_default()
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* ltconfig.in (dlpreopen): removed dld_preloaded_symbol_count
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* ltmain.in: added help for -avoid-versioning, -export-symbols,
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-module, add @SYMFILE@ if one of -export-dynamic, -dlopen or
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-dlpreopen is used
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* mail/deplibs.html: added Gordon Matzigkeit's inter-library
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dependencies article
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* mdemo/Makefile.am: removed -export-dynamic from LDFLAGS
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(no longer necessary, since libtool defines lt_preloaded_symbols
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when -dlopen is used), initialize with lt_preloaded_symbols
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1999-01-13 Alexandre Oliva <oliva@dcc.unicamp.br>
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* doc/libtool.texi (Test descriptions): cdemo-static works, thanks
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@ -21,7 +46,7 @@
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* ltconfig.in (NM): PATH search was not updated like in
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libtool.m4, in last Alexandre Oliva's change to it
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(sysv4*, ncr): pass all library dependencies
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* ltmain.in (dependency_libs, -R): use `dep' instead of `arg' to
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* ltmain.in (dependency_libs, -R): use `deplib' instead of `arg' to
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iterate, otherwise we'd overwrite `arg'
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(convenience, old_libs): if --disable-shared, convenience
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libraries are just old archives, as .lo's are of no use
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@ -6,7 +6,7 @@ AC_PROG_CC
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AC_EXEEXT
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AM_PROG_LIBTOOL
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AC_CHECK_HEADERS(string.h math.h)
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AC_CHECK_HEADERS(math.h)
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AC_CHECK_LIB(m, cos, LIBADD_M="-lm", LIBADD_M=)
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AC_SUBST(LIBADD_M)
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@ -24,21 +24,21 @@ USA. */
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#include <string.h>
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#endif
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struct dld_symlist
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struct lt_symlist
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{
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char *name;
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void *address;
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const char *name;
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lt_ptr_t address;
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};
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extern struct dld_symlist dld_preloaded_symbols[];
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extern const struct lt_symlist lt_preloaded_symbols[];
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#ifdef __CYGWIN32__
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int
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win32_force_data_import_address __P((void))
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{
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struct dld_symlist *s;
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const struct lt_symlist *s;
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s = dld_preloaded_symbols;
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s = lt_preloaded_symbols;
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while (s->name)
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{
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if (!strcmp ("nothing", s->name))
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@ -56,7 +56,7 @@ main (argc, argv)
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int argc;
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char **argv;
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{
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struct dld_symlist *s;
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const struct lt_symlist *s;
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int (*pfoo)() = 0;
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int (*phello)() = 0;
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int *pnothing = 0;
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@ -69,7 +69,7 @@ main (argc, argv)
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#endif
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/* Look up the symbols we require for this demonstration. */
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s = dld_preloaded_symbols;
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s = lt_preloaded_symbols;
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while (s->name)
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{
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if (s->address) {
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@ -51,8 +51,10 @@ USA. */
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#undef __P
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#if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(__CYGWIN32__) || defined(__cplusplus)
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# define __P(protos) protos
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# define lt_ptr_t void*
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#else
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# define __P(protos) ()
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# define lt_ptr_t char*
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#endif
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#ifdef __CYGWIN32__
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@ -1147,7 +1147,7 @@ no effect.
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@item -dlpreopen @var{file}
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Link @var{file} into the output program, and add its symbols to
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@var{dld_preloaded_symbols} (@pxref{Dlpreopening}).
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@var{lt_preloaded_symbols} (@pxref{Dlpreopening}).
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@item -export-dynamic
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Allow symbols from @var{output-file} to be resolved with @code{dlsym}
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@ -2373,14 +2373,16 @@ In order to use this feature, you must declare the objects you want your
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application to dlopen by using the @samp{-dlopen} or @samp{-dlpreopen}
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flags when you link your program (@pxref{Link mode}).
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@deftypefn {Structure} {typedef struct} dld_symbol @{ @w{char *@var{name};} @w{ptr_t @var{address};} @}
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@deftypefn {Structure} {typedef struct}
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lt_symbol @{ @w{const char *@var{name};} @w{lt_ptr_t @var{address};} @}
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The @var{name} attribute is a zero-terminated character string of the
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symbol name, such as @code{"fprintf"}. The @var{address} attribute is a
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generic pointer to the appropriate object, such as @code{&fprintf}.
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@end deftypefn
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@deftypevar {dld_symbol *} dld_preloaded_symbols
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An array of @var{dld_symbol} structures, representing all the preloaded
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@deftypevar {const lt_symbol *} lt_preloaded_symbols
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An array of @var{lt_symbol} structures, representing all the preloaded
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symbols linked into the program. For each @samp{-dlpreloaded} file
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there is an element with the @var{name} of the file and a @var{address}
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of @code{0}, followed by all symbols exported from this file.
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@ -2391,7 +2393,7 @@ Some compilers may allow identifiers which are not valid in ANSI C, such
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as dollar signs. Libtool only recognizes valid ANSI C symbols (an
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initial ASCII letter or underscore, followed by zero or more ASCII
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letters, digits, and underscores), so non-ANSI symbols will not appear
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in @var{dld_preloaded_symbols}.
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in @var{lt_preloaded_symbols}.
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@node Finding the dlname
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@section Finding the correct name to dlopen
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@ -12,7 +12,7 @@ LTDL_FLAGS =
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noinst_HEADERS = ltdl.h
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endif
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EXTRA_LTLIBRARIES = libltdl.la libtest.la
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EXTRA_LTLIBRARIES = libltdl.la libltdlc.la
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lib_LTLIBRARIES = @LIBLIBS@
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noinst_LTLIBRARIES = @NOINSTLIBS@
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@ -22,10 +22,10 @@ libltdl_la_LDFLAGS = $(LTDL_FLAGS)
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libltdl_la_LIBADD = $(LIBADD_DL)
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libltdl_la_DEPENDENCIES = libtool
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libtest_la_SOURCES = $(libltdl_la_SOURCES)
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libtest_la_LDFLAGS =
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libtest_la_LIBADD = $(libltdl_la_LIBADD)
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libltdl_la_DEPENDENCIES = libtool
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libltdlc_la_SOURCES = $(libltdl_la_SOURCES)
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libltdlc_la_LDFLAGS =
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libltdlc_la_LIBADD = $(libltdl_la_LIBADD)
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libltdlc_la_DEPENDENCIES = libtool
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libtool: ../libtool
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./config.status --recheck
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@ -63,7 +63,7 @@ static const char *symbol_error = "symbol not found";
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static const char *memory_error = "not enough memory";
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static const char *invalid_handle_error = "invalid handle";
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static const char *buffer_overflow_error = "internal buffer overflow";
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static const char *shutdown_error = "libraries already shutdown";
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static const char *shutdown_error = "library already shutdown";
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static const char *last_error;
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@ -299,7 +299,7 @@ dl = { LT_DLTYPE_TOP, dl_init, dl_exit,
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#define BIND_RESTRICTED 0
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#endif /* BIND_RESTRICTED */
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#define OPT_BIND_FLAGS (BIND_IMMEDIATE | BIND_NONFATAL | BIND_VERBOSE | DYNAMIC_PATH)
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#define LTDL_BIND_FLAGS (BIND_IMMEDIATE | BIND_NONFATAL | BIND_VERBOSE | DYNAMIC_PATH)
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static int
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shl_init ()
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@ -318,8 +318,7 @@ shl_open (handle, filename)
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lt_dlhandle handle;
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const char *filename;
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{
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handle->handle = shl_load (filename, OPT_BIND_FLAGS, 0L);
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/* the hp-docs say we should better abort() if errno==ENOSYM ;( */
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handle->handle = shl_load(filename, LTDL_BIND_FLAGS, 0L);
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if (!handle->handle) {
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last_error = unknown_error;
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return 1;
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@ -345,7 +344,7 @@ shl_sym (handle, symbol)
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{
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lt_ptr_t address;
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if (shl_findsym ((shl_t) (handle->handle), symbol, TYPE_UNDEFINED,
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if (shl_findsym((shl_t) (handle->handle), symbol, TYPE_UNDEFINED,
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&address) != 0 || !(handle->handle) || !address) {
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last_error = unknown_error;
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return 0;
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@ -497,17 +496,17 @@ wll = { LT_DLTYPE_TOP, wll_init, wll_exit,
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#if HAVE_DLPREOPEN
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/* emulate dynamic linking using dld_preloaded_symbols */
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/* emulate dynamic linking using preloaded_symbols */
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typedef struct lt_dlsymlists_t {
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struct lt_dlsymlists_t *next;
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lt_dlsymlist *syms;
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const lt_dlsymlist *syms;
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} lt_dlsymlists_t;
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static lt_dlsymlists_t *preloaded_symbols = 0;
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static int
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dldpre_init ()
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presym_init ()
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{
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/* Don't nullify preloaded_symbols here, it would prevent one
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from calling lt_dlpreload_default() before lt_dlinit() */
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@ -515,7 +514,7 @@ dldpre_init ()
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}
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static void
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dldpre_free_symlists ()
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presym_free_symlists ()
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{
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lt_dlsymlists_t *lists = preloaded_symbols;
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@ -529,7 +528,7 @@ dldpre_free_symlists ()
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}
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static int
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dldpre_exit ()
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presym_exit ()
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{
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/* Don't reset preloaded_symbols here; adding/removing symbols
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should be unrelated with init/exit */
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@ -537,8 +536,8 @@ dldpre_exit ()
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}
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static int
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dldpre_add_symlist (preloaded)
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lt_dlsymlist *preloaded;
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presym_add_symlist (preloaded)
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const lt_dlsymlist *preloaded;
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{
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lt_dlsymlists_t *tmp;
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lt_dlsymlists_t *lists = preloaded_symbols;
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@ -569,7 +568,7 @@ dldpre_add_symlist (preloaded)
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}
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static int
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dldpre_open (handle, filename)
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presym_open (handle, filename)
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lt_dlhandle handle;
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const char *filename;
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{
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@ -584,12 +583,12 @@ dldpre_open (handle, filename)
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return 1;
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}
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while (lists) {
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lt_dlsymlist *syms = lists->syms;
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const lt_dlsymlist *syms = lists->syms;
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while (syms->name) {
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if (!syms->address &&
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strcmp(syms->name, filename) == 0) {
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handle->handle = syms;
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handle->handle = (lt_ptr_t) syms;
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return 0;
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}
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syms++;
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@ -601,14 +600,14 @@ dldpre_open (handle, filename)
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}
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static int
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dldpre_close (handle)
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presym_close (handle)
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lt_dlhandle handle;
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{
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return 0;
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}
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static lt_ptr_t
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dldpre_sym (handle, symbol)
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presym_sym (handle, symbol)
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lt_dlhandle handle;
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const char *symbol;
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{
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@ -630,11 +629,11 @@ dldpre_sym (handle, symbol)
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static
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lt_dltype_t
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dldpre = { LT_DLTYPE_TOP, dldpre_init, dldpre_exit,
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dldpre_open, dldpre_close, dldpre_sym };
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presym = { LT_DLTYPE_TOP, presym_init, presym_exit,
|
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presym_open, presym_close, presym_sym };
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#undef LT_DLTYPE_TOP
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#define LT_DLTYPE_TOP &dldpre
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#define LT_DLTYPE_TOP &presym
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#endif
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@ -676,13 +675,13 @@ lt_dlinit ()
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int
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lt_dlpreopen (preloaded)
|
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lt_dlsymlist *preloaded;
|
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const lt_dlsymlist *preloaded;
|
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{
|
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#if HAVE_DLPREOPEN
|
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if (preloaded)
|
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return dldpre_add_symlist(preloaded);
|
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return presym_add_symlist(preloaded);
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else {
|
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dldpre_free_symlists();
|
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presym_free_symlists();
|
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return 0;
|
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}
|
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#else
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@ -835,7 +834,7 @@ find_library (handle, filename, have_dir, basename, search_path)
|
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if (tryall_dlopen(handle, filename) == 0)
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return 0;
|
||||
|
||||
if (have_dir && !search_path) {
|
||||
if (have_dir || !search_path) {
|
||||
last_error = file_not_found_error;
|
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return 1;
|
||||
}
|
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@ -899,7 +898,7 @@ find_file (filename, basename, have_dir, search_path)
|
||||
if (file)
|
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return file;
|
||||
|
||||
if (have_dir && !search_path) {
|
||||
if (have_dir || !search_path) {
|
||||
last_error = file_not_found_error;
|
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return 0;
|
||||
}
|
||||
@ -1157,6 +1156,10 @@ lt_dlsym (handle, symbol)
|
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last_error = invalid_handle_error;
|
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return 0;
|
||||
}
|
||||
if (!symbol) {
|
||||
last_error = symbol_error;
|
||||
return 0;
|
||||
}
|
||||
lensym = strlen(symbol);
|
||||
if (handle->name)
|
||||
lenhand = strlen(handle->name);
|
||||
|
||||
@ -69,21 +69,21 @@ typedef lt_ptr_t lt_dlhandle;
|
||||
#endif
|
||||
|
||||
typedef struct {
|
||||
char *name;
|
||||
const char *name;
|
||||
lt_ptr_t address;
|
||||
} lt_dlsymlist;
|
||||
|
||||
__BEGIN_DECLS
|
||||
_LTDLL_EXTERN int lt_dlinit __P((void));
|
||||
_LTDLL_EXTERN int lt_dlpreopen __P((lt_dlsymlist *preloaded));
|
||||
_LTDLL_EXTERN int lt_dlpreopen __P((const lt_dlsymlist *preloaded));
|
||||
_LTDLL_EXTERN int lt_dlexit __P((void));
|
||||
_LTDLL_EXTERN lt_dlhandle lt_dlopen __P((const char *filename));
|
||||
_LTDLL_EXTERN int lt_dlclose __P((lt_dlhandle handle));
|
||||
_LTDLL_EXTERN lt_ptr_t lt_dlsym __P((lt_dlhandle handle, const char *name));
|
||||
_LTDLL_EXTERN const char *lt_dlerror __P((void));
|
||||
|
||||
extern lt_dlsymlist dld_preloaded_symbols[];
|
||||
#define lt_dlpreopen_default() (lt_dlpreopen(dld_preloaded_symbols))
|
||||
extern const lt_dlsymlist lt_preloaded_symbols[];
|
||||
|
||||
__END_DECLS
|
||||
|
||||
#endif /* !_LTDL_H_ */
|
||||
|
||||
13
ltconfig.in
13
ltconfig.in
@ -1429,12 +1429,8 @@ EOF
|
||||
# Try sorting and uniquifying the output.
|
||||
if sort "$nlist" | uniq > "$nlist"T; then
|
||||
mv -f "$nlist"T "$nlist"
|
||||
wcout=`wc "$nlist" 2>/dev/null`
|
||||
count=`$echo "X$wcout" | $Xsed -e 's/^[ ]*\([0-9][0-9]*\).*$/\1/'`
|
||||
(test "$count" -ge 0) 2>/dev/null || count=-1
|
||||
else
|
||||
rm -f "$nlist"T
|
||||
count=-1
|
||||
fi
|
||||
|
||||
# Make sure that we snagged all the symbols we need.
|
||||
@ -1456,15 +1452,12 @@ EOF
|
||||
# define lt_ptr_t char *
|
||||
#endif
|
||||
|
||||
/* The number of symbols in dld_preloaded_symbols, -1 if unsorted. */
|
||||
int dld_preloaded_symbol_count = $count;
|
||||
|
||||
/* The mapping between symbol names and symbols. */
|
||||
struct {
|
||||
char *name;
|
||||
const struct {
|
||||
const char *name;
|
||||
lt_ptr_t address;
|
||||
}
|
||||
dld_preloaded_symbols[] =
|
||||
lt_preloaded_symbols[] =
|
||||
{
|
||||
EOF
|
||||
sed 's/^\(.*\) \(.*\)$/ {"\1", (lt_ptr_t) \&\2},/' < "$nlist" >> conftest.c
|
||||
|
||||
43
ltmain.in
43
ltmain.in
@ -625,6 +625,7 @@ compiler."
|
||||
ltlibs=
|
||||
module=no
|
||||
objs=
|
||||
preload=no
|
||||
prev=
|
||||
prevarg=
|
||||
release=
|
||||
@ -668,6 +669,12 @@ compiler."
|
||||
|
||||
case "$prev" in
|
||||
dlfiles|dlprefiles)
|
||||
if test "$preload" = no; then
|
||||
# Add the symbol object into the linking commands.
|
||||
compile_command="$compile_command @SYMFILE@"
|
||||
finalize_command="$finalize_command @SYMFILE@"
|
||||
preload=yes
|
||||
fi
|
||||
case "$arg" in
|
||||
*.la | *.lo) ;; # We handle these cases below.
|
||||
*)
|
||||
@ -748,10 +755,12 @@ compiler."
|
||||
else
|
||||
arg=
|
||||
fi
|
||||
|
||||
# Add the symbol object into the linking commands.
|
||||
compile_command="$compile_command @SYMFILE@"
|
||||
finalize_command="$finalize_command @SYMFILE@"
|
||||
if test "$preload" = no; then
|
||||
# Add the symbol object into the linking commands.
|
||||
compile_command="$compile_command @SYMFILE@"
|
||||
finalize_command="$finalize_command @SYMFILE@"
|
||||
preload=yes
|
||||
fi
|
||||
fi
|
||||
;;
|
||||
|
||||
@ -939,10 +948,10 @@ compiler."
|
||||
if test -n "$dependency_libs"; then
|
||||
# Extract -R from dependency_libs
|
||||
temp_deplibs=
|
||||
for dep in $dependency_libs; do
|
||||
case "$dep" in
|
||||
-R*) xrpath="$xrpath "`echo "X$dep" | $Xsed -e 's/^-R//'`;;
|
||||
*) temp_deplibs="$temp_deplibs $dep";;
|
||||
for deplib in $dependency_libs; do
|
||||
case "$deplib" in
|
||||
-R*) xrpath="$xrpath "`echo "X$deplib" | $Xsed -e 's/^-R//'`;;
|
||||
*) temp_deplibs="$temp_deplibs $deplib";;
|
||||
esac
|
||||
done
|
||||
dependency_libs="$temp_deplibs"
|
||||
@ -1922,7 +1931,7 @@ extern \"C\" {
|
||||
#endif
|
||||
|
||||
/* Prevent the only kind of declaration conflicts we can make. */
|
||||
#define dld_preloaded_symbols some_other_symbol
|
||||
#define lt_preloaded_symbols some_other_symbol
|
||||
|
||||
/* External symbol declarations for the compiler. */\
|
||||
"
|
||||
@ -1955,7 +1964,7 @@ extern \"C\" {
|
||||
|
||||
$echo >> "$output_objdir/$dlsyms" "\
|
||||
|
||||
#undef dld_preloaded_symbols
|
||||
#undef lt_preloaded_symbols
|
||||
|
||||
#if defined (__STDC__) && __STDC__
|
||||
# define lt_ptr_t void *
|
||||
@ -1964,11 +1973,11 @@ extern \"C\" {
|
||||
#endif
|
||||
|
||||
/* The mapping between symbol names and symbols. */
|
||||
struct {
|
||||
char *name;
|
||||
const struct {
|
||||
const char *name;
|
||||
lt_ptr_t address;
|
||||
}
|
||||
dld_preloaded_symbols[] =
|
||||
lt_preloaded_symbols[] =
|
||||
{\
|
||||
"
|
||||
|
||||
@ -2016,7 +2025,7 @@ dld_preloaded_symbols[] =
|
||||
esac
|
||||
else
|
||||
# We keep going just in case the user didn't refer to
|
||||
# dld_preloaded_symbols. The linker will fail if global_symbol_pipe
|
||||
# lt_preloaded_symbols. The linker will fail if global_symbol_pipe
|
||||
# really was required.
|
||||
if test -n "$dlfiles$dlprefiles"; then
|
||||
$echo "$modename: not configured to extract global symbols from dlpreopened files" 1>&2
|
||||
@ -3182,11 +3191,15 @@ a program from several object files.
|
||||
The following components of LINK-COMMAND are treated specially:
|
||||
|
||||
-all-static do not do any dynamic linking at all
|
||||
-avoid-versioning do not add a version suffix if possible
|
||||
-dlopen FILE \`-dlpreopen' FILE if it cannot be dlopened at runtime
|
||||
-dlpreopen FILE link in FILE and add its symbols to dld_preloaded_symbols
|
||||
-dlpreopen FILE link in FILE and add its symbols to lt_preloaded_symbols
|
||||
-export-dynamic allow symbols from OUTPUT-FILE to be resolved with dlsym(3)
|
||||
-export-symbols SYMFILE
|
||||
try to export only the symbols listed in SYMFILE
|
||||
-LLIBDIR search LIBDIR for required installed libraries
|
||||
-lNAME OUTPUT-FILE requires the installed library libNAME
|
||||
-module build a library that can dlopened
|
||||
-no-undefined declare that a library does not refer to external symbols
|
||||
-o OUTPUT-FILE create OUTPUT-FILE from the specified objects
|
||||
-release RELEASE specify package release information
|
||||
|
||||
213
mail/deplibs.html
Normal file
213
mail/deplibs.html
Normal file
@ -0,0 +1,213 @@
|
||||
<html>
|
||||
<head>
|
||||
<title>Libtool Inter-library Dependencies</title>
|
||||
<body bgcolor="#ffffff">
|
||||
<center><h1><img src="/graphics/libtool.gif" width=477 height=192
|
||||
alt="Libtool"></h1></center>
|
||||
|
||||
<h1>Inter-library Dependencies</h1>
|
||||
|
||||
<p>About twice a week, for the last five weeks, I've been receiving
|
||||
bug reports which tell me that libtool's inter-library dependency
|
||||
handling is broken.
|
||||
|
||||
<p>I know. I broke it intentionally, until I have the time to fix it
|
||||
myself, or somebody else takes the time to help me with it.
|
||||
|
||||
<p>These same people often give me a simple one-line patch which
|
||||
re-enables my old, simplistic inter-library dependencies, but nobody
|
||||
seems to want to test things thoroughly and come up with a real
|
||||
solution.
|
||||
|
||||
<p>If you don't care about the history, and you just want to help me
|
||||
out, jump to <a href="#solution">the bottom of this document</a>.
|
||||
|
||||
<h2>Background</h2>
|
||||
|
||||
<p>Libtool's basic premise is to make static and shared libraries
|
||||
behave the same way from a programmer's point of view. This allows
|
||||
users to build a libtoolized package with or without shared libraries,
|
||||
determined at configuration time. It does this by using a
|
||||
<dfn>libtool object</dfn> (<samp>.lo</samp>) and <dfn>libtool
|
||||
archive</dfn> (<samp>.la</samp>) abstraction, so that the package
|
||||
maintainer can use libtool to operate on these files without making
|
||||
any assumptions about their underlying representation.
|
||||
|
||||
<p>For the most part, this abstraction works well, and has made
|
||||
libtool as popular as it is today. Without this abstraction, it would
|
||||
be significantly harder to port libtool to new platforms.
|
||||
|
||||
<p>Unfortunately, what this abstraction has also done is reveal some
|
||||
fundamental inconsistencies with most shared library implementations.
|
||||
Every shared library implementation works well for `hello world'-type
|
||||
examples, but very few are robust and well-designed so that libtool
|
||||
doesn't need special tricks in order to build correct, featureful
|
||||
shared libraries.
|
||||
|
||||
<p>Providing inter-library dependencies is one feature that has
|
||||
revealed these kinds of inconsistencies.
|
||||
|
||||
<h2>The problem</h2>
|
||||
|
||||
<p>My orginal inter-library dependency code received rigourous testing
|
||||
in beta releases of <a href="http://www.red-bean.com/guile/">GNU
|
||||
Guile</a>. As soon as the Guile people started using my code, I
|
||||
received a flood of bug reports. People were reporting that
|
||||
<samp>libguile</samp> (Guile's main shared library) was failing to
|
||||
link, or that programs linked against <samp>libguile</samp> were
|
||||
dumping core.
|
||||
|
||||
<p>Not good.
|
||||
|
||||
<p>The Guile people chased this bug down to the following scenario:
|
||||
|
||||
<ol>
|
||||
<li>The user's system has a static regexp library installed,
|
||||
<samp>librx.a</samp>.
|
||||
|
||||
<li>Guile's <samp>configure</samp> script detects that the
|
||||
<samp>-lrx</samp> linker option can be used to link in
|
||||
<samp>librx</samp>.
|
||||
|
||||
<li>When <samp>libguile</samp> is built, the <samp>-lrx</samp> linker
|
||||
option is used.
|
||||
|
||||
<li>Some linkers fail at this point, because they don't allow shared
|
||||
libraries to contain or depend on static libraries.
|
||||
|
||||
<li>If the linker didn't fail, then a few programs are linked against
|
||||
<samp>libguile</samp>.
|
||||
|
||||
<li>On some systems, these programs core dump because
|
||||
<samp>libguile</samp> is a shared library that contains non-PIC code
|
||||
(from <samp>librx</samp>).
|
||||
</ol>
|
||||
|
||||
<h2>The interim solution</h2>
|
||||
|
||||
<p>I needed some way to respond to these reports. I saw my options (in
|
||||
order of my preference) as:
|
||||
|
||||
<ol>
|
||||
<li>Write code in <samp>ltmain.sh</samp> to prevent static libraries
|
||||
from appearing in inter-library dependencies. This would take some
|
||||
work, but obviously is the best solution.
|
||||
|
||||
<li>Find the systems that fail, and turn off inter-library
|
||||
dependencies on only those systems.
|
||||
|
||||
<li>Force the package maintainer to guarantee that static libraries
|
||||
never appear in inter-library dependencies.
|
||||
</ol>
|
||||
|
||||
<p>I immediately vetoed the last solution, because that would violate
|
||||
the whole point of using libtool, and would cause a lot of people to
|
||||
waste time solving a problem that really should be fixed by libtool.
|
||||
|
||||
<p>I preferred the first solution, but at the time of the reports, I
|
||||
didn't see an obviously simple mechanism for detecting the difference
|
||||
between shared and static libraries.
|
||||
|
||||
<p>So, in the meantime, I tried turning off inter-library dependencies
|
||||
on the systems that failed.
|
||||
|
||||
<p>I quickly discovered, to my chagrin, that many systems fail. So,
|
||||
it was be simpler for me to turn off <em>all</em> inter-library
|
||||
dependencies, then find out which systems work, rather than vice
|
||||
versa.
|
||||
|
||||
<h2>The current situation</h2>
|
||||
|
||||
<p>I've been busy trying to avoid bankruptcy. It's been over three
|
||||
months since I first turned off inter-library dependencies, and I
|
||||
still haven't completed the solution I want.
|
||||
|
||||
<p>I've been gearing up for the 1.1 release of libtool, because there
|
||||
is a high demand for a stable public release. So, I'm not going to
|
||||
introduce any destabilizing changes to the inter-library dependency
|
||||
code until after 1.1 is released.
|
||||
|
||||
<h2><a name="solution">The solution</a></h2>
|
||||
|
||||
<p>So, I want to tell you how you can help me solve the various
|
||||
dilemmas surrounding this issue:
|
||||
|
||||
<ol>
|
||||
<li>I need to find out more about the nature of the problems I ran
|
||||
into with Guile. Unfortunately, I cannot reproduce them in simple
|
||||
tests on my own platform (i586-pc-linux-gnulibc1), even though I think
|
||||
they were reported here. I need to find out which platforms already
|
||||
have perfect inter-library dependency support, how to work around the
|
||||
problem on other platforms, and, more importantly, exactly
|
||||
<em>why</em> some systems give me problems and others don't.
|
||||
|
||||
<p>On correct platforms, you can link <em>any</em> static library
|
||||
against a shared library via the <samp>-lNAME</samp> option without
|
||||
the linker complaining, then link a program against this library and
|
||||
run it without dumping core. I know that this scenario will always
|
||||
work fine on the following systems:
|
||||
|
||||
<ul>
|
||||
<li>None reported yet.
|
||||
</ul>
|
||||
|
||||
<p>I also know that on some systems, you can create a shared library
|
||||
linked against a static one, but running programs linked against such
|
||||
a library will dump core:
|
||||
|
||||
<ul>
|
||||
<li>None reported yet.
|
||||
</ul>
|
||||
|
||||
<p>Finally, there are some systems which won't even allow you to link
|
||||
a shared library against a static one:
|
||||
|
||||
<ul>
|
||||
<li>Solaris 2.x
|
||||
</ul>
|
||||
|
||||
<li>Help me figure out a good, portable way to detect if a given
|
||||
<samp>-lNAME</samp> option refers to a shared library or not, since
|
||||
that is needed as a workaround to the problem. Some suggestions so
|
||||
far have been:
|
||||
|
||||
<ul>
|
||||
<li>Link the library against a tiny test program, and:
|
||||
|
||||
<ul>
|
||||
<li>run <samp>ldd(1)</samp> on the test program and search for
|
||||
<samp>libNAME</samp> in the ldd output.
|
||||
<li>use the <samp>-verbose</samp> flag for GNU ld in order to see
|
||||
which library is actually linked.
|
||||
<li>run some sort of other program to determine if the library was
|
||||
dynamic.
|
||||
</ul>
|
||||
|
||||
<li>Track the <samp>-LDIR</samp> flags, do a search for the library,
|
||||
and then check whether it is shared by:
|
||||
|
||||
<ul>
|
||||
<li>using the <samp>file(1)</samp> program.
|
||||
<li>looking at its suffix.
|
||||
</ul>
|
||||
</ul>
|
||||
|
||||
<li>Contact any people you know who might be interested, get them to
|
||||
read this page, so that they can help me solve the problem.
|
||||
|
||||
<li>Send me money, so that I can devote more of my time to solving the
|
||||
problem.
|
||||
</ol>
|
||||
|
||||
<p>Thank you for your help, and have fun.
|
||||
|
||||
<hr>
|
||||
<a href="http://www.gimp.org/"><img src="/graphics/gfx_by_gimp.gif"
|
||||
align="right" border=0></a>
|
||||
|
||||
<p><a href="libtool.html">Back to the libtool home page.</a>
|
||||
|
||||
<address>
|
||||
Gordon Matzigkeit <a href="mailto:gord@profitpress.com"><gord@profitpress.com></a>
|
||||
</address>
|
||||
</html>
|
||||
@ -18,19 +18,18 @@ noinst_HEADERS = foo.h
|
||||
|
||||
bin_PROGRAMS = mdemo mdemo.debug
|
||||
|
||||
../libltdl/libtest.la: ../libltdl/libtool \
|
||||
../libltdl/libltdlc.la: ../libltdl/libtool \
|
||||
$(srcdir)/../libltdl/ltdl.c $(srcdir)/../libltdl/ltdl.h
|
||||
(cd ../libltdl; $(MAKE) libtest.la)
|
||||
(cd ../libltdl; $(MAKE) libltdlc.la)
|
||||
|
||||
# Create a version of mdemo that does dlopen.
|
||||
mdemo_SOURCES = main.c
|
||||
mdemo_LDADD = ../libltdl/libtest.la
|
||||
mdemo_LDFLAGS = -export-dynamic -dlopen foo1.la -dlopen libfoo2.la
|
||||
mdemo_DEPENDENCIES = ../libltdl/libtest.la foo1.la libfoo2.la
|
||||
mdemo_LDADD = ../libltdl/libltdlc.la
|
||||
mdemo_LDFLAGS = -dlopen foo1.la -dlopen libfoo2.la
|
||||
mdemo_DEPENDENCIES = ../libltdl/libltdlc.la foo1.la libfoo2.la
|
||||
|
||||
# Create an easier-to-debug version of mdemo.
|
||||
mdemo_debug_SOURCES = main.c
|
||||
mdemo_debug_LDADD = ../libltdl/libtest.la
|
||||
mdemo_debug_LDFLAGS = -static -export-dynamic \
|
||||
-dlopen foo1.la -dlopen libfoo2.la
|
||||
mdemo_debug_DEPENDENCIES = ../libltdl/libtest.la foo1.la libfoo2.la
|
||||
mdemo_debug_LDADD = ../libltdl/libltdlc.la
|
||||
mdemo_debug_LDFLAGS = -static -dlopen foo1.la -dlopen libfoo2.la
|
||||
mdemo_debug_DEPENDENCIES = ../libltdl/libltdlc.la foo1.la libfoo2.la
|
||||
|
||||
@ -92,6 +92,10 @@ main (int argc, char **argv)
|
||||
fprintf (stderr, "error during initialization: %s\n", lt_dlerror());
|
||||
return 1;
|
||||
}
|
||||
if (lt_dlpreopen(lt_preloaded_symbols) != 0) {
|
||||
fprintf (stderr, "error during initialization: %s\n", lt_dlerror());
|
||||
return 1;
|
||||
}
|
||||
|
||||
for (i = 1; i < argc; i++)
|
||||
if (test_dl(argv[i]))
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user