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elf: Generalize name-based DSO recognition in ldconfig

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This introduces <dl-is_dso.h> and the _dl_is_dso function.  A
test ensures that the official names of libc.so, ld.so, and their
versioned names are recognized.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Florian Weimer 2021-06-28 08:33:57 +02:00
parent b89d5de250
commit 6bf789d69e
4 changed files with 72 additions and 4 deletions
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3
elf/Makefile
View file

@ -223,7 +223,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-single_threaded tst-single_threaded-pthread \
tst-tls-ie tst-tls-ie-dlmopen argv0test \
tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
tst-tls20 tst-tls21 tst-dlmopen-dlerror tst-dlmopen-gethostbyname
tst-tls20 tst-tls21 tst-dlmopen-dlerror tst-dlmopen-gethostbyname \
tst-dl-is_dso
# reldep9
tests-internal += loadtest unload unload2 circleload1 \
neededtest neededtest2 neededtest3 neededtest4 \

33
elf/dl-is_dso.h Normal file
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@ -0,0 +1,33 @@
/* Heuristic for recognizing DSO file names.
Copyright (C) 2021 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 <stdbool.h>
#include <string.h>
/* Returns true if the file name looks like a DSO name. */
static bool
_dl_is_dso (const char *name)
{
/* Recognize lib*.so*, ld-*.so*, ld.so.*, ld64.so.*. ld-*.so*
matches both platform dynamic linker names like ld-linux.so.2,
and versioned dynamic loader names like ld-2.12.so. */
return (((strncmp (name, "lib", 3) == 0 || strncmp (name, "ld-", 3) == 0)
&& strstr (name, ".so") != NULL)
|| strncmp (name, "ld.so.", 6) == 0
|| strncmp (name, "ld64.so.", 8) == 0);
}

5
elf/ldconfig.c
View file

@ -43,6 +43,7 @@
#include <ldconfig.h>
#include <dl-cache.h>
#include <dl-hwcaps.h>
#include <dl-is_dso.h>
#include <dl-procinfo.h>
@ -842,9 +843,7 @@ search_dir (const struct dir_entry *entry)
subdirectory (if not already processing a glibc-hwcaps
subdirectory)? The dynamic linker is also considered as
shared library. */
if (((strncmp (direntry->d_name, "lib", 3) != 0
&& strncmp (direntry->d_name, "ld-", 3) != 0)
|| strstr (direntry->d_name, ".so") == NULL)
if (!_dl_is_dso (direntry->d_name)
&& (direntry->d_type == DT_REG
|| (entry->hwcaps == NULL
&& !is_hwcap_platform (direntry->d_name))))

35
elf/tst-dl-is_dso.c Normal file
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@ -0,0 +1,35 @@
/* Test heuristic for recognizing DSO file names.
Copyright (C) 2021 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 <dl-is_dso.h>
#include <gnu/lib-names.h>
#include <support/check.h>
static int
do_test (void)
{
/* Official ABI names. */
TEST_VERIFY (_dl_is_dso (LIBC_SO));
TEST_VERIFY (_dl_is_dso (LD_SO));
/* Version-based names. The version number does not matter. */
TEST_VERIFY (_dl_is_dso ("libc-2.12.so"));
TEST_VERIFY (_dl_is_dso ("ld-2.12.so"));
return 0;
}
#include <support/test-driver.c>