225 lines
7.3 KiB
Diff
225 lines
7.3 KiB
Diff
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commit 54b12733959238204d7b0e46e69fc7f7d8890b20
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Fri Mar 11 08:23:56 2022 +0100
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nss: Protect against errno changes in function lookup (bug 28953)
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dlopen may clobber errno. The nss_test_errno module uses an ELF
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constructor to achieve that, but there could be internal errors
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during dlopen that cause this, too. Therefore, the NSS framework
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has to guard against such errno clobbers.
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__nss_module_get_function is currently the only function that calls
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__nss_module_load, so it is sufficient to save and restore errno
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around this call.
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Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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(cherry picked from commit 9bdf92c79d63b42f931101bb6df87129c408b0c4)
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diff --git a/nss/Makefile b/nss/Makefile
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index e223243d9d62041c..716bc8f6ef5276b0 100644
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--- a/nss/Makefile
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+++ b/nss/Makefile
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@@ -60,7 +60,8 @@ tests = test-netdb test-digits-dots tst-nss-getpwent bug17079 \
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tst-nss-test1 \
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tst-nss-test2 \
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tst-nss-test4 \
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- tst-nss-test5
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+ tst-nss-test5 \
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+ tst-nss-test_errno
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xtests = bug-erange
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tests-container = \
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@@ -132,7 +133,7 @@ libnss_compat-inhibit-o = $(filter-out .os,$(object-suffixes))
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ifeq ($(build-static-nss),yes)
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tests-static += tst-nss-static
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endif
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-extra-test-objs += nss_test1.os nss_test2.os
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+extra-test-objs += nss_test1.os nss_test2.os nss_test_errno.os
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include ../Rules
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@@ -166,19 +167,26 @@ rtld-tests-LDFLAGS += -Wl,--dynamic-list=nss_test.ver
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libof-nss_test1 = extramodules
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libof-nss_test2 = extramodules
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+libof-nss_test_errno = extramodules
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$(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
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$(build-module)
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$(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
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$(build-module)
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+$(objpfx)/libnss_test_errno.so: $(objpfx)nss_test_errno.os $(link-libc-deps)
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+ $(build-module)
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$(objpfx)nss_test2.os : nss_test1.c
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# Use the nss_files suffix for these objects as well.
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$(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
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$(make-link)
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$(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
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$(make-link)
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+$(objpfx)/libnss_test_errno.so$(libnss_files.so-version): \
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+ $(objpfx)/libnss_test_errno.so
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+ $(make-link)
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$(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
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$(objpfx)/libnss_test1.so$(libnss_files.so-version) \
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- $(objpfx)/libnss_test2.so$(libnss_files.so-version)
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+ $(objpfx)/libnss_test2.so$(libnss_files.so-version) \
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+ $(objpfx)/libnss_test_errno.so$(libnss_files.so-version)
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ifeq (yes,$(have-thread-library))
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$(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
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diff --git a/nss/nss_module.c b/nss/nss_module.c
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index b28cb94a6a0aeb41..3a4a464256121e41 100644
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--- a/nss/nss_module.c
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+++ b/nss/nss_module.c
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@@ -330,8 +330,18 @@ name_search (const void *left, const void *right)
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void *
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__nss_module_get_function (struct nss_module *module, const char *name)
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{
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+ /* A successful dlopen might clobber errno. */
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+ int saved_errno = errno;
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+
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if (!__nss_module_load (module))
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- return NULL;
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+ {
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+ /* Reporting module load failure is currently inaccurate. See
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+ bug 22041. Not changing errno is the conservative choice. */
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+ __set_errno (saved_errno);
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+ return NULL;
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+ }
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+
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+ __set_errno (saved_errno);
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function_name *name_entry = bsearch (name, nss_function_name_array,
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array_length (nss_function_name_array),
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diff --git a/nss/nss_test_errno.c b/nss/nss_test_errno.c
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new file mode 100644
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index 0000000000000000..680f8a07b97fe263
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--- /dev/null
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+++ b/nss/nss_test_errno.c
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@@ -0,0 +1,58 @@
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+/* NSS service provider with errno clobber.
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+ Copyright (C) 2022 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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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <errno.h>
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+#include <nss.h>
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+#include <stdlib.h>
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+
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+/* Catch misnamed and functions. */
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+#pragma GCC diagnostic error "-Wmissing-prototypes"
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+NSS_DECLARE_MODULE_FUNCTIONS (test_errno)
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+
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+static void __attribute__ ((constructor))
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+init (void)
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+{
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+ /* An arbitrary error code which is otherwise not used. */
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+ errno = ELIBBAD;
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+}
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+
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+/* Lookup functions for pwd follow that do not return any data. */
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+
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+/* Catch misnamed function definitions. */
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+
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+enum nss_status
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+_nss_test_errno_setpwent (int stayopen)
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+{
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+ setenv ("_nss_test_errno_setpwent", "yes", 1);
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+ return NSS_STATUS_SUCCESS;
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+}
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+
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+enum nss_status
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+_nss_test_errno_getpwent_r (struct passwd *result,
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+ char *buffer, size_t size, int *errnop)
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+{
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+ setenv ("_nss_test_errno_getpwent_r", "yes", 1);
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+ return NSS_STATUS_NOTFOUND;
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+}
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+
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+enum nss_status
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+_nss_test_errno_endpwent (void)
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+{
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+ setenv ("_nss_test_errno_endpwent", "yes", 1);
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+ return NSS_STATUS_SUCCESS;
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+}
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diff --git a/nss/tst-nss-test_errno.c b/nss/tst-nss-test_errno.c
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new file mode 100644
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index 0000000000000000..d2c42dd363a38b0e
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--- /dev/null
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+++ b/nss/tst-nss-test_errno.c
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@@ -0,0 +1,61 @@
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+/* getpwent failure when dlopen clobbers errno (bug 28953).
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+ Copyright (C) 2022 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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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <nss.h>
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+#include <support/check.h>
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+#include <stdlib.h>
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+#include <errno.h>
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+#include <stdbool.h>
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+#include <pwd.h>
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+#include <string.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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+ __nss_configure_lookup ("passwd", "files test_errno");
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+
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+ errno = 0;
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+ setpwent ();
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+ TEST_COMPARE (errno, 0);
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+
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+ bool root_seen = false;
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+ while (true)
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+ {
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+ errno = 0;
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+ struct passwd *e = getpwent ();
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+ if (e == NULL)
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+ break;
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+ if (strcmp (e->pw_name, "root"))
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+ root_seen = true;
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+ }
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+
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+ TEST_COMPARE (errno, 0);
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+ TEST_VERIFY (root_seen);
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+
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+ errno = 0;
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+ endpwent ();
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+ TEST_COMPARE (errno, 0);
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+
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+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes");
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+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes");
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+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes");
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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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