bin/140143: [patch] dlopen(3) doesn't promote RTLD_GLOBAL for linked libraries

[David Naylor]

The following reply was made to PR bin/140143; it has been noted by GNATS.

From: David Naylor <naylor.b.david at gmail.com>
To: bug-followup at freebsd.org
Cc:  
Subject: Re: bin/140143: [patch] dlopen(3) doesn't promote RTLD_GLOBAL for linked libraries
Date: Mon, 31 May 2010 16:14:30 +0200

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 Attached is an undated test case.  Extract and run make.  This works without 
 failure under Linux but fails under FreeBSD.  
 
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 Content-Disposition: attachment;
 	filename="rtld_global.shar"
 
 # This is a shell archive.  Save it in a file, remove anything before
 # this line, and then unpack it by entering "sh file".  Note, it may
 # create directories; files and directories will be owned by you and
 # have default permissions.
 #
 # This archive contains:
 #
 #	rtld_global
 #	rtld_global/Makefile
 #	rtld_global/libmaster.c
 #	rtld_global/main.c
 #	rtld_global/libslave.c
 #	rtld_global/common.h
 #	rtld_global/libplugin.c
 #
 echo c - rtld_global
 mkdir -p rtld_global > /dev/null 2>&1
 echo x - rtld_global/Makefile
 sed 's/^X//' >rtld_global/Makefile << '54185eeffb995a36288ad17f38c2bdc0'
 X.ORDER: test clean
 X.SUFFIXES: .a .c .o .so .so.1
 X.SILENT:
 X
 XCFLAGS=-Wall -rdynamic
 X
 X.if defined(TRIGGER)
 XCFLAGS+=-DTRIGGER
 X.endif
 X
 XCC=cc
 XAR=ar
 XLN=ln
 X
 Xall: clean
 X	echo "Running test without linking: "
 X	${MAKE} test clean #> /dev/null
 X	echo "done"
 X	echo
 X	echo "Running test with linking: "
 X	${MAKE} test clean -DLINKED #> /dev/null
 X	echo "done"
 X	echo
 X	echo "Running test with linking (trigger): "
 X	${MAKE} test clean -DLINKED -DTRIGGER
 X	echo "done"
 X
 Xclean:
 X	rm -f *.a *.o *.so* main
 X
 Xtest: main libmaster.so libslave.so
 X	env LD_LIBRARY_PATH=${PWD} ./main
 X
 X.c.o:
 X	${CC} ${CFLAGS} -c -fPIC -o $@ $<
 X
 X.c.so:
 X	${CC} ${CFLAGS} -fPIC -shared -Wl,-soname,$@ -o $@ $<
 X
 X.if defined(LINKED)
 Xlibplugin.so: libplugin.c libmaster.so
 X	${CC} ${CFLAGS} -DLINKED -fPIC -L. -lmaster -shared -Wl,-soname,$@ -o $@ $<
 X.endif
 X
 Xmain: main.o libplugin.so
 X	cc ${CFLAGS} -o main main.o
 54185eeffb995a36288ad17f38c2bdc0
 echo x - rtld_global/libmaster.c
 sed 's/^X//' >rtld_global/libmaster.c << '4c7e49ccff36dd33ab5357b611fe5d83'
 X#include "common.h"
 X
 Xint master_func() {
 X  void* libslave;
 X  func_t func;
 X
 X  printf("libmaster: opening libslave:");
 X  libslave = dlopen("libslave.so", RTLD_NOW);
 X  STATUS_CHECK(libslave);
 X
 X  printf("libmaster: getting symbol 'libslave::slave_func':");
 X  func = (func_t)dlsym(libslave, "slave_func");
 X  STATUS_CHECK(func);
 X
 X  printf("libmaster: calling 'libslave::slave_func'...\n");
 X  return func();
 X}
 X
 Xconst char* master_name() {
 X  return "libmaster.1";
 X}
 4c7e49ccff36dd33ab5357b611fe5d83
 echo x - rtld_global/main.c
 sed 's/^X//' >rtld_global/main.c << 'cb6b43e30862d408f1380a58a3050ed8'
 X#include "common.h"
 X
 Xint main(int argc, char** argv) {
 X  void* libplugin;
 X  func_t func;
 X
 X  printf("main: opening libplugin:");
 X  libplugin = dlopen("libplugin.so", RTLD_LAZY /*| RTLD_GLOBAL*/);
 X  STATUS_CHECK(libplugin);
 X
 X  printf("main: getting symbol 'libplugin::plugin_func':");
 X  func = (func_t)dlsym(libplugin, "plugin_func");
 X  STATUS_CHECK(func);
 X
 X  printf("main: calling 'libplugin::plugin_func'...\n");
 X  return func();
 X}
 cb6b43e30862d408f1380a58a3050ed8
 echo x - rtld_global/libslave.c
 sed 's/^X//' >rtld_global/libslave.c << '6027f0c5e11bc3f1d64c5398f3095d35'
 X#include <stdio.h>
 X
 X/* Forward declaration from libmaster */
 Xconst char* master_name();
 X
 Xint slave_func() {
 X  printf("libslave: %s\n", master_name());
 X  return 0;
 X}
 6027f0c5e11bc3f1d64c5398f3095d35
 echo x - rtld_global/common.h
 sed 's/^X//' >rtld_global/common.h << '96ded3809880f52ca04e85b8175d157f'
 X#include <dlfcn.h>
 X#include <stdio.h>
 X
 X#define STATUS_CHECK(var)                                                     \
 X  if ((var) == NULL) {                                                          \
 X    printf(" failure (%s)\n", dlerror());                                     \
 X    return 1;                                                                 \
 X  } else                                                                      \
 X    printf(" success\n")
 X
 Xtypedef int (*func_t)();
 96ded3809880f52ca04e85b8175d157f
 echo x - rtld_global/libplugin.c
 sed 's/^X//' >rtld_global/libplugin.c << 'a806cc4670bd702634b1d6e2d06150e5'
 X#include "common.h"
 X
 X#ifdef LINKED
 Xint master_func();
 X#endif
 X
 Xint plugin_func() {
 X  func_t func;
 X
 X#if !defined(LINKED)
 X  void* libmaster;
 X
 X  printf("libplugin: opening libmaster:");
 X  libmaster = dlopen("libmaster.so", RTLD_LAZY | RTLD_GLOBAL);
 X  STATUS_CHECK(libmaster);
 X#elif !defined(TRIGGER)
 X  void* libplugin;
 X
 X  printf("libplugin: exposing symbols globally:");
 X  libplugin = dlopen("libplugin.so", RTLD_NOLOAD | RTLD_GLOBAL);
 X  STATUS_CHECK(libplugin);
 X#else
 X  void* libmaster;
 X
 X  printf("libplugin: exposing libmaster symbols globally:");
 X  libmaster = dlopen("libmaster.so", RTLD_NOLOAD | RTLD_GLOBAL);
 X  STATUS_CHECK(libmaster);
 X#endif
 X
 X#if !defined(LINKED)
 X  printf("libplugin: getting symbol 'libmaster::master_func':");
 X  func = (func_t)dlsym(libmaster, "master_func");
 X  STATUS_CHECK(func);
 X#else
 X  func = &master_func;
 X#endif
 X
 X  printf("libplugin: calling 'libmaster::master_func'...\n");
 X  return func();
 X}
 a806cc4670bd702634b1d6e2d06150e5
 exit
 
 
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