225 lines
8.7 KiB
Diff
225 lines
8.7 KiB
Diff
commit b2964eb1d9a6b8ab1250e8a881cf406182da5875
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Wed Apr 21 19:49:51 2021 +0200
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dlfcn: Failures after dlmopen should not terminate process [BZ #24772]
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Commit 9e78f6f6e7134a5f299cc8de77370218f8019237 ("Implement
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_dl_catch_error, _dl_signal_error in libc.so [BZ #16628]") has the
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side effect that distinct namespaces, as created by dlmopen, now have
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separate implementations of the rtld exception mechanism. This means
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that the call to _dl_catch_error from libdl in a secondary namespace
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does not actually install an exception handler because the
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thread-local variable catch_hook in the libc.so copy in the secondary
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namespace is distinct from that of the base namepace. As a result, a
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dlsym/dlopen/... failure in a secondary namespace terminates the process
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with a dynamic linker error because it looks to the exception handler
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mechanism as if no handler has been installed.
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This commit restores GLRO (dl_catch_error) and uses it to set the
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handler in the base namespace.
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Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Conflicts:
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elf/Makefile
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diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c
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index 06732460ea1512cd..e08ac3afef302817 100644
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--- a/dlfcn/dlerror.c
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+++ b/dlfcn/dlerror.c
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@@ -167,8 +167,10 @@ _dlerror_run (void (*operate) (void *), void *args)
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result->errstring = NULL;
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}
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- result->errcode = _dl_catch_error (&result->objname, &result->errstring,
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- &result->malloced, operate, args);
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+ result->errcode = GLRO (dl_catch_error) (&result->objname,
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+ &result->errstring,
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+ &result->malloced,
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+ operate, args);
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/* If no error we mark that no error string is available. */
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result->returned = result->errstring == NULL;
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diff --git a/elf/Makefile b/elf/Makefile
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index a811919ba4568d64..e0919486a14cab1a 100644
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--- a/elf/Makefile
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+++ b/elf/Makefile
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@@ -216,6 +216,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
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tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
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tst-tls20 tst-tls21 \
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tst-rtld-run-static \
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+ tst-dlmopen-dlerror \
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# reldep9
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tests-internal += loadtest unload unload2 circleload1 \
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neededtest neededtest2 neededtest3 neededtest4 \
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@@ -349,6 +350,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
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libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
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libmarkermod5-1 libmarkermod5-2 libmarkermod5-3 libmarkermod5-4 \
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libmarkermod5-5 tst-tls20mod-bad tst-tls21mod \
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+ tst-dlmopen-dlerror-mod \
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# Most modules build with _ISOMAC defined, but those filtered out
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# depend on internal headers.
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@@ -1546,6 +1548,10 @@ $(objpfx)tst-sonamemove-dlopen.out: \
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$(objpfx)tst-sonamemove-runmod1.so \
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$(objpfx)tst-sonamemove-runmod2.so
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+$(objpfx)tst-dlmopen-dlerror: $(libdl)
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+$(objpfx)tst-dlmopen-dlerror-mod.so: $(libdl) $(libsupport)
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+$(objpfx)tst-dlmopen-dlerror.out: $(objpfx)tst-dlmopen-dlerror-mod.so
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+
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# Override -z defs, so that we can reference an undefined symbol.
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# Force lazy binding for the same reason.
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LDFLAGS-tst-latepthreadmod.so = \
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diff --git a/elf/dl-error-skeleton.c b/elf/dl-error-skeleton.c
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index 9cb002ccfed2c7b4..7801aa433b12275f 100644
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--- a/elf/dl-error-skeleton.c
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+++ b/elf/dl-error-skeleton.c
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@@ -248,4 +248,16 @@ _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
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catch_hook = old_catch;
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receiver = old_receiver;
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}
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+
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+/* Forwarder used for initializing GLRO (_dl_catch_error). */
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+int
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+_rtld_catch_error (const char **objname, const char **errstring,
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+ bool *mallocedp, void (*operate) (void *),
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+ void *args)
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+{
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+ /* The reference to _dl_catch_error will eventually be relocated to
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+ point to the implementation in libc.so. */
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+ return _dl_catch_error (objname, errstring, mallocedp, operate, args);
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+}
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+
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#endif /* DL_ERROR_BOOTSTRAP */
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diff --git a/elf/rtld.c b/elf/rtld.c
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index 461d8c114a875a9b..c445b5ca25dea193 100644
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--- a/elf/rtld.c
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+++ b/elf/rtld.c
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@@ -365,6 +365,7 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
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._dl_lookup_symbol_x = _dl_lookup_symbol_x,
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._dl_open = _dl_open,
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._dl_close = _dl_close,
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+ ._dl_catch_error = _rtld_catch_error,
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._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
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#ifdef HAVE_DL_DISCOVER_OSVERSION
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._dl_discover_osversion = _dl_discover_osversion
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diff --git a/elf/tst-dlmopen-dlerror-mod.c b/elf/tst-dlmopen-dlerror-mod.c
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new file mode 100644
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index 0000000000000000..7e95dcdeacf005be
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--- /dev/null
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+++ b/elf/tst-dlmopen-dlerror-mod.c
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@@ -0,0 +1,41 @@
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+/* Check that dlfcn errors are reported properly after dlmopen. Test module.
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+ Copyright (C) 2021 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <http://www.gnu.org/licenses/>. */
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+
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+#include <dlfcn.h>
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+#include <stddef.h>
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+#include <support/check.h>
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+
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+/* Note: This object is not linked into the main program, so we cannot
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+ use delayed test failure reporting via TEST_VERIFY etc., and have
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+ to use FAIL_EXIT1 (or something else that calls exit). */
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+
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+void
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+call_dlsym (void)
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+{
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+ void *ptr = dlsym (NULL, "does not exist");
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+ if (ptr != NULL)
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+ FAIL_EXIT1 ("dlsym did not fail as expected");
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+}
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+
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+void
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+call_dlopen (void)
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+{
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+ void *handle = dlopen ("tst-dlmopen-dlerror does not exist", RTLD_NOW);
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+ if (handle != NULL)
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+ FAIL_EXIT1 ("dlopen did not fail as expected");
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+}
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diff --git a/elf/tst-dlmopen-dlerror.c b/elf/tst-dlmopen-dlerror.c
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new file mode 100644
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index 0000000000000000..e864d2fe4c3484ab
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--- /dev/null
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+++ b/elf/tst-dlmopen-dlerror.c
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@@ -0,0 +1,37 @@
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+/* Check that dlfcn errors are reported properly after dlmopen.
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+ Copyright (C) 2021 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <http://www.gnu.org/licenses/>. */
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+
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+#include <stddef.h>
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+#include <support/check.h>
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+#include <support/xdlfcn.h>
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+
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+static int
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+do_test (void)
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+{
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+ void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-dlerror-mod.so",
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+ RTLD_NOW);
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+ void (*call_dlsym) (void) = xdlsym (handle, "call_dlsym");
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+ void (*call_dlopen) (void) = xdlsym (handle, "call_dlopen");
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+
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+ call_dlsym ();
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+ call_dlopen ();
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+
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+ return 0;
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+}
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+
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+#include <support/test-driver.c>
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diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
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index 7b0a667629ddc06a..d6d02aa3ccffba33 100644
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--- a/sysdeps/generic/ldsodefs.h
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+++ b/sysdeps/generic/ldsodefs.h
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@@ -647,6 +647,12 @@ struct rtld_global_ro
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void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
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Lmid_t nsid, int argc, char *argv[], char *env[]);
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void (*_dl_close) (void *map);
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+ /* libdl in a secondary namespace (after dlopen) must use
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+ _dl_catch_error from the main namespace, so it has to be
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+ exported in some way. */
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+ int (*_dl_catch_error) (const char **objname, const char **errstring,
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+ bool *mallocedp, void (*operate) (void *),
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+ void *args);
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void *(*_dl_tls_get_addr_soft) (struct link_map *);
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#ifdef HAVE_DL_DISCOVER_OSVERSION
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int (*_dl_discover_osversion) (void);
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@@ -889,6 +895,9 @@ extern int _dl_catch_error (const char **objname, const char **errstring,
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void *args);
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libc_hidden_proto (_dl_catch_error)
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+/* Used for initializing GLRO (_dl_catch_error). */
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+extern __typeof__ (_dl_catch_error) _rtld_catch_error attribute_hidden;
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+
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/* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
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Otherwise, store a copy of the raised exception in *EXCEPTION,
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which has to be freed by _dl_exception_free. As a special case, if
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