[PATCH 09/11] elf: Add glibc-hwcaps subdirectory support to ld.so cache processing
Adhemerval Zanella
adhemerval.zanella@linaro.org
Tue Dec 1 17:45:26 GMT 2020
On 09/11/2020 15:41, Florian Weimer via Libc-alpha wrote:
> This recognizes the DL_CACHE_HWCAP_EXTENSION flag and picks up
> the supported cache entry with the highest priority.
Maybe add a brief description of what DL_CACHE_HWCAP_EXTENSION aims to do?
Patch looks good in general, some comments below.
> ---
> elf/Makefile | 18 ++
> elf/dl-cache.c | 182 +++++++++++++++++-
> elf/dl-hwcaps.c | 78 ++++++++
> elf/dl-hwcaps.h | 19 ++
> elf/tst-glibc-hwcaps-cache.c | 45 +++++
> .../etc/ld.so.conf | 2 +
> elf/tst-glibc-hwcaps-cache.root/postclean.req | 0
> elf/tst-glibc-hwcaps-cache.script | 2 +
> elf/tst-glibc-hwcaps-prepend-cache.c | 133 +++++++++++++
> .../postclean.req | 0
> 10 files changed, 476 insertions(+), 3 deletions(-)
> create mode 100644 elf/tst-glibc-hwcaps-cache.c
> create mode 100644 elf/tst-glibc-hwcaps-cache.root/etc/ld.so.conf
> create mode 100644 elf/tst-glibc-hwcaps-cache.root/postclean.req
> create mode 100644 elf/tst-glibc-hwcaps-cache.script
> create mode 100644 elf/tst-glibc-hwcaps-prepend-cache.c
> create mode 100644 elf/tst-glibc-hwcaps-prepend-cache.root/postclean.req
>
> diff --git a/elf/Makefile b/elf/Makefile
> index e26ac16b44..80e94b9ee2 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -171,6 +171,12 @@ tests-container := \
> tst-ldconfig-bad-aux-cache \
> tst-ldconfig-ld_so_conf-update
>
> +ifeq (no,$(build-hardcoded-path-in-tests))
> +# This is an ld.so.cache test, and RPATH/RUNPATH in the executable
> +# interferes with its test objectives.
> +tests-container += tst-glibc-hwcaps-prepend-cache
> +endif
> +
> tests := tst-tls9 tst-leaks1 \
> tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \
> tst-auxv tst-stringtable
Ok.
> @@ -1859,6 +1865,14 @@ $(objpfx)tst-glibc-hwcaps-prepend.out: \
> $< > $@; \
> $(evaluate-test)
>
> +# Like tst-glibc-hwcaps-prepend, but uses a container and loads the
> +# library via ld.so.cache. Test setup is contained in the test
> +# itself.
> +$(objpfx)tst-glibc-hwcaps-prepend-cache: $(libdl)
> +$(objpfx)tst-glibc-hwcaps-prepend-cache.out: \
> + $(objpfx)tst-glibc-hwcaps-prepend-cache $(objpfx)libmarkermod1-1.so \
> + $(objpfx)libmarkermod1-2.so $(objpfx)libmarkermod1-3.so
> +
> # tst-glibc-hwcaps-mask checks that --glibc-hwcaps-mask can be used to
> # suppress all auto-detected subdirectories.
> $(objpfx)tst-glibc-hwcaps-mask: $(objpfx)libmarkermod1-1.so
> @@ -1870,3 +1884,7 @@ $(objpfx)tst-glibc-hwcaps-mask.out: \
> --glibc-hwcaps-mask does-not-exist \
> $< > $@; \
> $(evaluate-test)
> +
> +# Generic dependency for sysdeps implementation of
> +# tst-glibc-hwcaps-cache.
> +$(objpfx)tst-glibc-hwcaps-cache.out: $(objpfx)tst-glibc-hwcaps
Ok.
> diff --git a/elf/dl-cache.c b/elf/dl-cache.c
> index 02c46ffb0c..13efc6f95f 100644
> --- a/elf/dl-cache.c
> +++ b/elf/dl-cache.c
> @@ -35,6 +35,132 @@ static struct cache_file *cache;
> static struct cache_file_new *cache_new;
> static size_t cachesize;
>
> +#ifdef SHARED
> +/* This is used to cache the priorities of glibc-hwcaps
> + subdirectories. The elements of _dl_cache_priorities correspond to
> + the strings in the cache_extension_tag_glibc_hwcaps section. */
> +static uint32_t *glibc_hwcaps_priorities;
> +static uint32_t glibc_hwcaps_priorities_length;
> +static uint32_t glibc_hwcaps_priorities_allocated;
> +
> +/* True if the full malloc was used to allocated the array. */
> +static bool glibc_hwcaps_priorities_malloced;
> +
> +/* Deallocate the glibc_hwcaps_priorities array. */
> +static void
> +glibc_hwcaps_priorities_free (void)
> +{
> + /* When the minimal malloc is in use, free does not do anything,
> + so it does not make sense to call it. */
> + if (glibc_hwcaps_priorities_malloced)
> + free (glibc_hwcaps_priorities);
> + glibc_hwcaps_priorities = NULL;
> + glibc_hwcaps_priorities_allocated = 0;
> +}
> +
> +/* Return the priority of the cache_extension_tag_glibc_hwcaps section
> + entry at INDEX. Zero means do not use. Otherwise, lower values
> + indicate greater preference. */
> +static uint32_t __attribute__ ((noinline, noclone))
I have a feeling I have asked it before, but why does it need noclone/noinline
here?
> +glibc_hwcaps_priority (uint32_t index)
> +{
> + /* Using a zero-length array as an indicator that nothing has been
> + loaded is not a problem: It does not lead to repeated
> + initialization attempts because caches without an extension
> + section are processed without calling this function (unless the
> + file is corrupted). */
> + if (glibc_hwcaps_priorities_length == 0)
Maybe an early exit here? It allow move the code one identation left
and makes it more readable.
> + {
> + struct cache_extension_all_loaded ext;
> + if (!cache_extension_load (cache_new, cache, cachesize, &ext))
> + return 0;
> +
> + uint32_t length
> + = (ext.sections[cache_extension_tag_glibc_hwcaps].size
> + / sizeof (uint32_t));
> + if (length > glibc_hwcaps_priorities_allocated)
> + {
> + glibc_hwcaps_priorities_free ();
> +
> + glibc_hwcaps_priorities = malloc (length * sizeof (uint32_t));
> + if (glibc_hwcaps_priorities == NULL)
> + /* Disable hwcaps on memory allocation error. */
> + return 0;
> +
> + glibc_hwcaps_priorities_allocated = length;
> + glibc_hwcaps_priorities_malloced = __rtld_malloc_is_complete ();
> + }
> +
> + /* Compute the priorities for the subdirectories by merging the
> + array in the cache with the dl_hwcaps_priorities array. */
> + const uint32_t *left
> + = ext.sections[cache_extension_tag_glibc_hwcaps].base;
> + const uint32_t *left_end = left + length;
> + struct dl_hwcaps_priority *right = _dl_hwcaps_priorities;
> + struct dl_hwcaps_priority *right_end
> + = right + _dl_hwcaps_priorities_length;
> + uint32_t *result = glibc_hwcaps_priorities;
> +
> + while (left < left_end && right < right_end)
> + {
> + uint32_t string_table_index = *left;
> + if (string_table_index < cachesize)
> + {
> + const char *left_name
> + = (const char *) cache + string_table_index;
> + uint32_t left_name_length = strlen (left_name);
> + uint32_t to_compare;
> + if (left_name_length < right->name_length)
> + to_compare = left_name_length;
> + else
> + to_compare = right->name_length;
> + int cmp = memcmp (left_name, right->name, to_compare);
> + if (cmp == 0)
> + {
> + if (left_name_length < right->name_length)
> + cmp = -1;
> + else if (left_name_length > right->name_length)
> + cmp = 1;
> + }
> + if (cmp == 0)
> + {
> + *result = right->priority;
> + ++result;
> + ++left;
> + ++right;
> + }
Maybe add as the 'else' within the 'cmp == 0' below?
> + else if (cmp < 0)
> + {
> + *result = 0;
> + ++result;
> + ++left;
> + }
> + else
> + ++right;
> + }
> + else
> + {
> + *result = 0;
> + ++result;
> + }
> + }
> + while (left < left_end)
> + {
> + *result = 0;
> + ++result;
> + ++left;
> + }
> +
> + glibc_hwcaps_priorities_length = length;
> + }
> +
> + if (index < glibc_hwcaps_priorities_length)
> + return glibc_hwcaps_priorities[index];
> + else
> + return 0;
> +}
> +#endif /* SHARED */
> +
Ok.
> /* True if PTR is a valid string table index. */
> static inline bool
> _dl_cache_verify_ptr (uint32_t ptr, size_t string_table_size)
> @@ -74,6 +200,9 @@ search_cache (const char *string_table, uint32_t string_table_size,
> int left = 0;
> int right = nlibs - 1;
> const char *best = NULL;
> +#ifdef SHARED
> + uint32_t best_priority = 0;
> +#endif
>
> while (left <= right)
> {
> @@ -129,6 +258,11 @@ search_cache (const char *string_table, uint32_t string_table_size,
> {
> if (best == NULL || flags == GLRO (dl_correct_cache_id))
> {
> + /* Named/extension hwcaps get slightly different
> + treatment: We keep searching for a better
> + match. */
> + bool named_hwcap = false;
> +
> if (entry_size >= sizeof (struct file_entry_new))
> {
> /* The entry is large enough to include
Ok.
> @@ -136,7 +270,18 @@ search_cache (const char *string_table, uint32_t string_table_size,
> struct file_entry_new *libnew
> = (struct file_entry_new *) lib;
>
> - if (libnew->hwcap & hwcap_exclude)
> +#ifdef SHARED
> + named_hwcap = dl_cache_hwcap_extension (libnew);
> +#endif
> +
> + /* The entries with named/extension hwcaps
> + have been exhausted. Return the best
> + match encountered so far if there is
> + one. */
> + if (!named_hwcap && best != NULL)
> + break;
> +
> + if ((libnew->hwcap & hwcap_exclude) && !named_hwcap)
> continue;
> if (GLRO (dl_osversion)
> && libnew->osversion > GLRO (dl_osversion))
Ok.
> @@ -146,14 +291,41 @@ search_cache (const char *string_table, uint32_t string_table_size,
> && ((libnew->hwcap & _DL_HWCAP_PLATFORM)
> != platform))
> continue;
> +
> +#ifdef SHARED
> + /* For named hwcaps, determine the priority
> + and see if beats what has been found so
> + far. */
> + if (named_hwcap)
> + {
> + uint32_t entry_priority
> + = glibc_hwcaps_priority (libnew->hwcap);
> + if (entry_priority == 0)
> + /* Not usable at all. Skip. */
> + continue;
> + else if (best == NULL
> + || entry_priority < best_priority)
> + /* This entry is of higher priority
> + than the previous one, or it is the
> + first entry. */
> + best_priority = entry_priority;
> + else
> + /* An entry has already been found,
> + but it is a better match. */
> + continue;
> + }
> +#endif /* SHARED */
> }
Ok.
>
> best = string_table + lib->value;
>
> - if (flags == GLRO (dl_correct_cache_id))
> + if (flags == GLRO (dl_correct_cache_id)
> + && !named_hwcap)
> /* We've found an exact match for the shared
> object and no general `ELF' release. Stop
> - searching. */
> + searching, but not if a named (extension)
> + hwcap is used. In this case, an entry with
> + a higher priority may come up later. */
> break;
> }
> }
Ok.
> @@ -346,5 +518,9 @@ _dl_unload_cache (void)
> __munmap (cache, cachesize);
> cache = NULL;
> }
> +#ifdef SHARED
> + /* This marks the glibc_hwcaps_priorities array as out-of-date. */
> + glibc_hwcaps_priorities_length = 0;
> +#endif
> }
> #endif
Ok.
> diff --git a/elf/dl-hwcaps.c b/elf/dl-hwcaps.c
> index f611f3a1a6..51cc787b54 100644
> --- a/elf/dl-hwcaps.c
> +++ b/elf/dl-hwcaps.c
> @@ -89,6 +89,81 @@ copy_hwcaps (struct copy_hwcaps *target, const char *hwcaps,
> }
> }
>
> +struct dl_hwcaps_priority *_dl_hwcaps_priorities;
> +uint32_t _dl_hwcaps_priorities_length;
> +
> +/* Allocate _dl_hwcaps_priorities and fill it with data. */
> +static void
> +compute_priorities (size_t total_count, const char *prepend,
> + int32_t bitmask, const char *mask)
I think bitmask should be a 'uint32' here.
> +{
> + _dl_hwcaps_priorities = malloc (total_count
> + * sizeof (*_dl_hwcaps_priorities));
> + if (_dl_hwcaps_priorities == NULL)
> + _dl_signal_error (ENOMEM, NULL, NULL,
> + N_("cannot create HWCAP priorities"));
> + _dl_hwcaps_priorities_length = total_count;
> +
> + /* First the prepended subdirectories. */
> + size_t i = 0;
> + {
> + struct dl_hwcaps_split sp;
> + _dl_hwcaps_split_init (&sp, prepend);
> + while (_dl_hwcaps_split (&sp))
> + {
> + _dl_hwcaps_priorities[i].name = sp.segment;
> + _dl_hwcaps_priorities[i].name_length = sp.length;
> + _dl_hwcaps_priorities[i].priority = i + 1;
> + ++i;
> + }
> + }
> +
Ok.
> + /* Then the built-in subdirectories that are actually active. */
> + {
> + struct dl_hwcaps_split_masked sp;
> + _dl_hwcaps_split_masked_init (&sp, _dl_hwcaps_subdirs, bitmask, mask);
> + while (_dl_hwcaps_split_masked (&sp))
> + {
> + _dl_hwcaps_priorities[i].name = sp.split.segment;
> + _dl_hwcaps_priorities[i].name_length = sp.split.length;
> + _dl_hwcaps_priorities[i].priority = i + 1;
> + ++i;
> + }
> + }
> + assert (i == total_count);
> +}
> +
Ok.
> +/* Sort the _dl_hwcaps_priorities array by name. */
> +static void
> +sort_priorities_by_name (void)
> +{
> + /* Insertion sort. There is no need to link qsort into the dynamic
> + loader for such a short array. */
> + for (size_t i = 1; i < _dl_hwcaps_priorities_length; ++i)
> + for (size_t j = i; j > 0; --j)
> + {
> + struct dl_hwcaps_priority *previous = _dl_hwcaps_priorities + j - 1;
> + struct dl_hwcaps_priority *current = _dl_hwcaps_priorities + j;
> +
> + /* Bail out if current is greater or equal to the previous
> + value. */
> + uint32_t to_compare;
> + if (current->name_length < previous->name_length)
> + to_compare = current->name_length;
> + else
> + to_compare = previous->name_length;
> + int cmp = memcmp (current->name, previous->name, to_compare);
> + if (cmp >= 0
> + || (cmp == 0 && current->name_length >= previous->name_length))
> + break;
> +
> + /* Swap *previous and *current. */
> + struct dl_hwcaps_priority tmp = *previous;
> + *previous = *current;
> + *current = tmp;
> + }
> +}
> +
Ok.
> /* Return an array of useful/necessary hardware capability names. */
> const struct r_strlenpair *
> _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
> @@ -111,6 +186,9 @@ _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
> update_hwcaps_counts (&hwcaps_counts, glibc_hwcaps_prepend, -1, NULL);
> update_hwcaps_counts (&hwcaps_counts, _dl_hwcaps_subdirs,
> hwcaps_subdirs_active, glibc_hwcaps_mask);
> + compute_priorities (hwcaps_counts.count, glibc_hwcaps_prepend,
> + hwcaps_subdirs_active, glibc_hwcaps_mask);
> + sort_priorities_by_name ();
>
> /* Each hwcaps subdirectory has a GLIBC_HWCAPS_PREFIX string prefix
> and a "/" suffix once stored in the result. */
Ok.
> diff --git a/elf/dl-hwcaps.h b/elf/dl-hwcaps.h
> index ab39d8a46d..ddfdde278e 100644
> --- a/elf/dl-hwcaps.h
> +++ b/elf/dl-hwcaps.h
> @@ -132,4 +132,23 @@ _dl_hwcaps_subdirs_build_bitmask (int subdirs, int active)
> return mask ^ ((1U << inactive) - 1);
> }
>
> +/* Pre-computed glibc-hwcaps subdirectory priorities. Used in
> + dl-cache.c to quickly find the proprities for the stored HWCAP
> + names. */
> +struct dl_hwcaps_priority
> +{
> + /* The name consists of name_length bytes at name (not necessarily
> + null-terminated). */
> + const char *name;
> + uint32_t name_length;
> +
> + /* Priority of this name. A positive number. */
> + uint32_t priority;
> +};
> +
> +/* Pre-computed hwcaps priorities. Set up by
> + _dl_important_hwcaps. */
> +extern struct dl_hwcaps_priority *_dl_hwcaps_priorities attribute_hidden;
> +extern uint32_t _dl_hwcaps_priorities_length attribute_hidden;
> +
> #endif /* _DL_HWCAPS_H */
Ok.
> diff --git a/elf/tst-glibc-hwcaps-cache.c b/elf/tst-glibc-hwcaps-cache.c
> new file mode 100644
> index 0000000000..4bad56afc0
> --- /dev/null
> +++ b/elf/tst-glibc-hwcaps-cache.c
> @@ -0,0 +1,45 @@
> +/* Wrapper to invoke tst-glibc-hwcaps in a container, to test ld.so.cache.
> + Copyright (C) 2020 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +/* This program is just a wrapper that runs ldconfig followed by
> + tst-glibc-hwcaps. The actual test is provided via an
> + implementation in a sysdeps subdirectory. */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <support/support.h>
> +#include <unistd.h>
> +
> +int
> +main (int argc, char **argv)
> +{
> + /* Run ldconfig to populate the cache. */
> + {
> + char *command = xasprintf ("%s/ldconfig", support_install_rootsbindir);
> + if (system (command) != 0)
> + return 1;
> + free (command);
> + }
> +
> + /* Reuse tst-glibc-hwcaps. Since this code is running in a
> + container, we can launch it directly. */
> + char *path = xasprintf ("%s/elf/tst-glibc-hwcaps", support_objdir_root);
> + execv (path, argv);
> + printf ("error: execv of %s failed: %m\n", path);
> + return 1;
> +}
Ok, it should be simple enough to require use libsupport fork/timeout check.
> diff --git a/elf/tst-glibc-hwcaps-cache.root/etc/ld.so.conf b/elf/tst-glibc-hwcaps-cache.root/etc/ld.so.conf
> new file mode 100644
> index 0000000000..e1e74dbda2
> --- /dev/null
> +++ b/elf/tst-glibc-hwcaps-cache.root/etc/ld.so.conf
> @@ -0,0 +1,2 @@
> +# This file was created to suppress a warning from ldconfig:
> +# /sbin/ldconfig: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf: No such file or directory
> diff --git a/elf/tst-glibc-hwcaps-cache.root/postclean.req b/elf/tst-glibc-hwcaps-cache.root/postclean.req
> new file mode 100644
> index 0000000000..e69de29bb2
Ok.
> diff --git a/elf/tst-glibc-hwcaps-cache.script b/elf/tst-glibc-hwcaps-cache.script
> new file mode 100644
> index 0000000000..46cb5fd553
> --- /dev/null
> +++ b/elf/tst-glibc-hwcaps-cache.script
> @@ -0,0 +1,2 @@
> +# test-container does not support scripts in sysdeps directories, so
> +# collect everything in one file.
Ok.
> diff --git a/elf/tst-glibc-hwcaps-prepend-cache.c b/elf/tst-glibc-hwcaps-prepend-cache.c
> new file mode 100644
> index 0000000000..eedbf5f6df
> --- /dev/null
> +++ b/elf/tst-glibc-hwcaps-prepend-cache.c
> @@ -0,0 +1,133 @@
> +/* Test that --glibc-hwcaps-prepend works, using dlopen and /etc/ld.so.cache.
> + Copyright (C) 2020 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <dlfcn.h>
> +#include <stddef.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xdlfcn.h>
> +#include <support/xunistd.h>
> +
> +/* Invoke /sbin/ldconfig with some error checking. */
> +static void
> +run_ldconfig (void)
> +{
> + char *command = xasprintf ("%s/ldconfig", support_install_rootsbindir);
> + TEST_COMPARE (system (command), 0);
> + free (command);
> +}
> +
> +/* The library under test. */
> +#define SONAME "libmarkermod1.so"
> +
> +static int
> +do_test (void)
> +{
> + if (dlopen (SONAME, RTLD_NOW) != NULL)
> + FAIL_EXIT1 (SONAME " is already on the search path");
> +
> + /* Install the default implementation of libmarkermod1.so. */
> + xmkdirp ("/etc", 0777);
> + support_write_file_string ("/etc/ld.so.conf", "/glibc-test/lib\n");
> + xmkdirp ("/glibc-test/lib/glibc-hwcaps/prepend2", 0777);
> + xmkdirp ("/glibc-test/lib/glibc-hwcaps/prepend3", 0777);
> + {
> + char *src = xasprintf ("%s/elf/libmarkermod1-1.so", support_objdir_root);
> + support_copy_file (src, "/glibc-test/lib/" SONAME);
> + free (src);
> + }
Ok.
> + run_ldconfig ();
> + {
> + /* The default implementation can now be loaded. */
> + void *handle = xdlopen (SONAME, RTLD_NOW);
> + int (*marker1) (void) = xdlsym (handle, "marker1");
> + TEST_COMPARE (marker1 (), 1);
> + xdlclose (handle);
> + }
Ok.
> +
> + /* Add the first override to the directory that is searched last. */
> + {
> + char *src = xasprintf ("%s/elf/libmarkermod1-2.so", support_objdir_root);
> + support_copy_file (src, "/glibc-test/lib/glibc-hwcaps/prepend2/"
> + SONAME);
> + free (src);
> + }
> + {
> + /* This is still the first implementation. The cache has not been
> + updated. */
> + void *handle = xdlopen (SONAME, RTLD_NOW);
> + int (*marker1) (void) = xdlsym (handle, "marker1");
> + TEST_COMPARE (marker1 (), 1);
> + xdlclose (handle);
> + }
Ok.
> + run_ldconfig ();
> + {
> + /* After running ldconfig, it is the second implementation. */
> + void *handle = xdlopen (SONAME, RTLD_NOW);
> + int (*marker1) (void) = xdlsym (handle, "marker1");
> + TEST_COMPARE (marker1 (), 2);
> + xdlclose (handle);
> + }
> +
Ok.
> + /* Add the second override to the directory that is searched first. */
> + {
> + char *src = xasprintf ("%s/elf/libmarkermod1-3.so", support_objdir_root);
> + support_copy_file (src, "/glibc-test/lib/glibc-hwcaps/prepend3/"
> + SONAME);
> + free (src);
> + }
> + {
> + /* This is still the second implementation. */
> + void *handle = xdlopen (SONAME, RTLD_NOW);
> + int (*marker1) (void) = xdlsym (handle, "marker1");
> + TEST_COMPARE (marker1 (), 2);
> + xdlclose (handle);
> + }
Ok.
> + run_ldconfig ();
> + {
> + /* After running ldconfig, it is the third implementation. */
> + void *handle = xdlopen (SONAME, RTLD_NOW);
> + int (*marker1) (void) = xdlsym (handle, "marker1");
> + TEST_COMPARE (marker1 (), 3);
> + xdlclose (handle);
> + }
> +
Ok.
Should we test the case of shared memory removal, for instance:
1. Remove second override, without ldconfig
2. Remove third override, run ldconfig
3. Add both second and third back, run ldconfig, remove third
4. Keep second, run ldconfig
> + return 0;
> +}
> +
> +static void
> +prepare (int argc, char **argv)
> +{
> + const char *no_restart = "no-restart";
> + if (argc == 2 && strcmp (argv[1], no_restart) == 0)
> + return;
> + /* Re-execute the test with an explicit loader invocation. */
> + execl (support_objdir_elf_ldso,
> + support_objdir_elf_ldso,
> + "--glibc-hwcaps-prepend", "prepend3:prepend2",
> + argv[0], no_restart,
> + NULL);
> + printf ("error: execv of %s failed: %m\n", argv[0]);
> + _exit (1);
> +}
> +
> +#define PREPARE prepare
> +#include <support/test-driver.c>
> diff --git a/elf/tst-glibc-hwcaps-prepend-cache.root/postclean.req b/elf/tst-glibc-hwcaps-prepend-cache.root/postclean.req
> new file mode 100644
> index 0000000000..e69de29bb2
>
Ok.
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