elf: Add tst-ldconfig-ld_so_conf-update test
Commit Message
From: Alexandra Hájková <ahajkova@redhat.com>
Test ldconfig after /etc/ld.so.conf update and verify a running process
observes changes to /etc/ld.so.cache.
The test uses the test-in-container framework.
---
elf/Makefile | 11 +-
elf/tst-ldconfig-ld-mod.c | 8 +
elf/tst-ldconfig-ld_so_conf-update.c | 143 ++++++++++++++++++
.../postclean.req | 0
.../tst-ldconfig-ld_so_conf-update.script | 1 +
5 files changed, 160 insertions(+), 3 deletions(-)
create mode 100644 elf/tst-ldconfig-ld-mod.c
create mode 100644 elf/tst-ldconfig-ld_so_conf-update.c
create mode 100644 elf/tst-ldconfig-ld_so_conf-update.root/postclean.req
create mode 100644 elf/tst-ldconfig-ld_so_conf-update.root/tst-ldconfig-ld_so_conf-update.script
Comments
Hi Alexandra,
The patch looks good to me, overall.
I only have questions and nitpicks, which are as follows:
> Test ldconfig after /etc/ld.so.conf update and verify a running process
> observes changes to /etc/ld.so.cache.
Does this test for a bug that was reported and fixed at some point? If yes, is
there a bug number that can be included?
Also, looks like the intention of the test is to verify running processes'
obseration of cache changes, and not ldconfig itself. Am I right?
> diff --git a/elf/Makefile b/elf/Makefile
> index b2b3be203f..5a8d60c6a8 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -162,8 +162,9 @@ tests-static-internal := tst-tls1-static tst-tls2-static \
> CRT-tst-tls1-static-non-pie := $(csu-objpfx)crt1.o
> tst-tls1-static-non-pie-no-pie = yes
>
> -tests-container = \
> - tst-ldconfig-bad-aux-cache
> +tests-container := \
> + tst-ldconfig-bad-aux-cache \
> + tst-ldconfig-ld_so_conf-update
>
> tests := tst-tls9 tst-leaks1 \
> tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \
> @@ -292,7 +293,8 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
> tst-auditmanymod4 tst-auditmanymod5 tst-auditmanymod6 \
> tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 \
> tst-initlazyfailmod tst-finilazyfailmod \
> - tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2
> + tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2 \
> + tst-ldconfig-ld-mod
> # Most modules build with _ISOMAC defined, but those filtered out
> # depend on internal headers.
> modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\
> @@ -1627,3 +1629,6 @@ $(objpfx)tst-dlopenfailmod1.so: \
> $(shared-thread-library) $(objpfx)tst-dlopenfaillinkmod.so
> LDFLAGS-tst-dlopenfaillinkmod.so = -Wl,-soname,tst-dlopenfail-missingmod.so
> $(objpfx)tst-dlopenfailmod2.so: $(shared-thread-library)
> +
> +$(objpfx)tst-ldconfig-ld_so_conf-update.out: $(objpfx)tst-ldconfig-ld-mod.so
> +$(objpfx)tst-ldconfig-ld_so_conf-update: $(libdl)
Looks okay.
> diff --git a/elf/tst-ldconfig-ld-mod.c b/elf/tst-ldconfig-ld-mod.c
> new file mode 100644
> index 0000000000..acd6609739
> --- /dev/null
> +++ b/elf/tst-ldconfig-ld-mod.c
> @@ -0,0 +1,8 @@
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +void
> +bar (void)
> +{
> + printf ("Called DSO.\n");
> +}
Looks okay minus glibc's two space indent.
> diff --git a/elf/tst-ldconfig-ld_so_conf-update.c b/elf/tst-ldconfig-ld_so_conf-update.c
> new file mode 100644
> index 0000000000..59de51c494
> --- /dev/null
> +++ b/elf/tst-ldconfig-ld_so_conf-update.c
> @@ -0,0 +1,143 @@
> +/* Test ldconfig after /etc/ld.so.conf update and verify a running process
> + observes changes to /etc/ld.so.cache.
> +
> + Copyright (C) 2019 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; see the file COPYING.LIB. If
> + not, see <https://www.gnu.org/licenses/>. */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +
> +#include <support/capture_subprocess.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xdlfcn.h>
> +#include <support/xstdio.h>
> +#include <support/xunistd.h>
> +
> +#define DSO "libldconfig-ld-mod.so"
> +#define DSO_DIR "/tmp/tst-ldconfig"
> +#define CONF "/etc/ld.so.conf"
Looks okay.
> +static void
> +execv_wrapper (void *args)
> +{
> + char **argv = args;
> +
> + execv (argv[0], argv);
> + FAIL_EXIT1 ("execv: %m");
> +}
Perhaps rename to 'run_ldconfig' and drop the use of args? This function is
only ever called to run ldconfig, and with the same args each time.
> +int
> +open_dso (const char *msg)
> +{
> + void *dso;
> + char *err;
> + int ret = 0;
> +
> + /* RTLD_NOW - all undefined symbols in the library are resolved
> + * before dlopen() returns. If this cannot be done, an error
> + * is returned.
> + * RTLD_GLOBAL - The symbols defined by this library will be made
> + * available for symbol resolution of subsequently loaded libraries. */
> + dso = dlopen (DSO, RTLD_NOW | RTLD_GLOBAL);
> + if (dso == NULL)
> + {
> + err = dlerror ();
> + printf ("%s dlerror: %s\n", msg, err);
> + ret = 1;
> + }
> + /* Clear any errors. */
> + dlerror ();
> +
> + return ret;
> +}
Since we aren't using the "expected" error messages in any way except
logging it, and since passing a string is a bit awkward, we could maybe
drop this entire function, and replace calls to it with:
(for expected failures)
TEST_VERIFY_EXIT (dlopen (DSO, RTLD_NOW | RTLD_GLOBAL) == NULL);
or
(for the final successful call)
TEST_VERIFY_EXIT (dlopen (DSO, RTLD_NOW | RTLD_GLOBAL) != NULL);
> +/* Create a new directory.
> + Copy a test shared object there.
> + Try to dlopen it by soname. This should fail.
> + (Directory is not searched.)
> + Run ldconfig.
> + Try to dlopen it again. It should still fail.
> + (Directory is still not searched.)
> + Add the directory to /etc/ld.so.conf.
> + Try to dlopen it again. It should still fail.
> + (The loader does not read /etc/ld.so.conf, only /etc/ld.so.cache.)
> + Run ldconfig.
> + Try to dlopen it again. This should finally succeed. */
Description is clear. There's a missing double space before the last sentence.
> +static int
> +do_test (void)
> +{
> + char *prog = xasprintf ("%s/ldconfig", support_install_rootsbindir);
> + char *args[] = { prog, NULL };
Could go into 'run_ldconfig' (i.e. execv_wrapper).
> + FILE *fp;
> + struct support_capture_subprocess result;
Could be declared at point of first use.
> + /* Create the needed directories. */
Missing double space.
> + xmkdirp ("/var/cache/ldconfig", 0777);
> + xmkdirp (DSO_DIR, 0777);
> +
> + /* Rename the DSO to start with "lib" because there's an undocumented
> + filter in ldconfig where it ignores any file that doesn't start with
> + "lib" (for regular shared libraries) or "ld-" (for ld-linux-*). */
> + if (rename ("/usr/lib64/tst-ldconfig-ld-mod.so",
> + "/tmp/tst-ldconfig/libldconfig-ld-mod.so"))
> + FAIL_EXIT1 ("Renaming/moving the DSO failed: %m");
Looks okay.
> + /* Open the DSO. We expect this to fail - test_ldconfig directory
> + * is not searched. */
The directory you used is tst-ldconfig.
> + if (!open_dso ("[Expected] "))
> + FAIL_EXIT1
> + ("We expect dlopen to fail at this point - test dir is not searched.");
Could be replaced with that line I suggested earlier:
TEST_VERIFY_EXIT (dlopen (DSO, RTLD_NOW | RTLD_GLOBAL) == NULL);
> + fp = xfopen (CONF, "a+");
> + if (!fp)
> + FAIL_EXIT1 ("creating /etc/ld.so.conf failed: %m");
> + xfclose (fp);
Looks okay.
> + /* Run ldconfig. */
> + result = support_capture_subprocess (execv_wrapper, args);
> + support_capture_subprocess_check (&result, "execv", 0, sc_allow_none);
> +
> + /* Try to dlopen the same DSO again, we expect this to fail again. */
> + if (!open_dso ("[Expected] "))
> + FAIL_EXIT1 ("We expect dlopen to fail at this point!.");
> +
> + /* Add test_ldconfig directory to /etc/ld.so.conf. */
> + fp = xfopen (CONF, "w");
> + if (!(fwrite (DSO_DIR, 1, sizeof (DSO_DIR), fp)))
> + FAIL_EXIT1 ("updating /etc/ld.so.conf failed: %m");
> + xfclose (fp);
> +
> + /* Try to dlopen the same DSO again, we expect this to still fail. */
> + if (!open_dso ("[Expected] "))
> + FAIL_EXIT1 ("We expect dlopen to fail at this point!.");
> +
> + /* Run ldconfig again. */
> + result = support_capture_subprocess (execv_wrapper, args);
> + support_capture_subprocess_check (&result, "execv", 0, sc_allow_none);
> + support_capture_subprocess_free (&result);
> +
> + if (open_dso ("[Unexpected] "))
> + FAIL_EXIT1 ("Dlopen failed.");
Looks okay minus the one reference to test_ldconfig. Of course, it will change a
bit if you go for my dlopen and run_ldconfig suggestions.
Cheers,
Arjun
@@ -162,8 +162,9 @@ tests-static-internal := tst-tls1-static tst-tls2-static \
CRT-tst-tls1-static-non-pie := $(csu-objpfx)crt1.o
tst-tls1-static-non-pie-no-pie = yes
-tests-container = \
- tst-ldconfig-bad-aux-cache
+tests-container := \
+ tst-ldconfig-bad-aux-cache \
+ tst-ldconfig-ld_so_conf-update
tests := tst-tls9 tst-leaks1 \
tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \
@@ -292,7 +293,8 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
tst-auditmanymod4 tst-auditmanymod5 tst-auditmanymod6 \
tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 \
tst-initlazyfailmod tst-finilazyfailmod \
- tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2
+ tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2 \
+ tst-ldconfig-ld-mod
# Most modules build with _ISOMAC defined, but those filtered out
# depend on internal headers.
modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\
@@ -1627,3 +1629,6 @@ $(objpfx)tst-dlopenfailmod1.so: \
$(shared-thread-library) $(objpfx)tst-dlopenfaillinkmod.so
LDFLAGS-tst-dlopenfaillinkmod.so = -Wl,-soname,tst-dlopenfail-missingmod.so
$(objpfx)tst-dlopenfailmod2.so: $(shared-thread-library)
+
+$(objpfx)tst-ldconfig-ld_so_conf-update.out: $(objpfx)tst-ldconfig-ld-mod.so
+$(objpfx)tst-ldconfig-ld_so_conf-update: $(libdl)
new file mode 100644
@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void
+bar (void)
+{
+ printf ("Called DSO.\n");
+}
new file mode 100644
@@ -0,0 +1,143 @@
+/* Test ldconfig after /etc/ld.so.conf update and verify a running process
+ observes changes to /etc/ld.so.cache.
+
+ Copyright (C) 2019 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; see the file COPYING.LIB. If
+ not, see <https://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <support/capture_subprocess.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xdlfcn.h>
+#include <support/xstdio.h>
+#include <support/xunistd.h>
+
+#define DSO "libldconfig-ld-mod.so"
+#define DSO_DIR "/tmp/tst-ldconfig"
+#define CONF "/etc/ld.so.conf"
+
+static void
+execv_wrapper (void *args)
+{
+ char **argv = args;
+
+ execv (argv[0], argv);
+ FAIL_EXIT1 ("execv: %m");
+}
+
+int
+open_dso (const char *msg)
+{
+ void *dso;
+ char *err;
+ int ret = 0;
+
+ /* RTLD_NOW - all undefined symbols in the library are resolved
+ * before dlopen() returns. If this cannot be done, an error
+ * is returned.
+ * RTLD_GLOBAL - The symbols defined by this library will be made
+ * available for symbol resolution of subsequently loaded libraries. */
+ dso = dlopen (DSO, RTLD_NOW | RTLD_GLOBAL);
+ if (dso == NULL)
+ {
+ err = dlerror ();
+ printf ("%s dlerror: %s\n", msg, err);
+ ret = 1;
+ }
+ /* Clear any errors. */
+ dlerror ();
+
+ return ret;
+}
+
+/* Create a new directory.
+ Copy a test shared object there.
+ Try to dlopen it by soname. This should fail.
+ (Directory is not searched.)
+ Run ldconfig.
+ Try to dlopen it again. It should still fail.
+ (Directory is still not searched.)
+ Add the directory to /etc/ld.so.conf.
+ Try to dlopen it again. It should still fail.
+ (The loader does not read /etc/ld.so.conf, only /etc/ld.so.cache.)
+ Run ldconfig.
+ Try to dlopen it again. This should finally succeed. */
+static int
+do_test (void)
+{
+ char *prog = xasprintf ("%s/ldconfig", support_install_rootsbindir);
+ char *args[] = { prog, NULL };
+ FILE *fp;
+ struct support_capture_subprocess result;
+
+ /* Create the needed directories. */
+ xmkdirp ("/var/cache/ldconfig", 0777);
+ xmkdirp (DSO_DIR, 0777);
+
+ /* Rename the DSO to start with "lib" because there's an undocumented
+ filter in ldconfig where it ignores any file that doesn't start with
+ "lib" (for regular shared libraries) or "ld-" (for ld-linux-*). */
+ if (rename ("/usr/lib64/tst-ldconfig-ld-mod.so",
+ "/tmp/tst-ldconfig/libldconfig-ld-mod.so"))
+ FAIL_EXIT1 ("Renaming/moving the DSO failed: %m");
+
+
+ /* Open the DSO. We expect this to fail - test_ldconfig directory
+ * is not searched. */
+ if (!open_dso ("[Expected] "))
+ FAIL_EXIT1
+ ("We expect dlopen to fail at this point - test dir is not searched.");
+ fp = xfopen (CONF, "a+");
+ if (!fp)
+ FAIL_EXIT1 ("creating /etc/ld.so.conf failed: %m");
+ xfclose (fp);
+
+ /* Run ldconfig. */
+ result = support_capture_subprocess (execv_wrapper, args);
+ support_capture_subprocess_check (&result, "execv", 0, sc_allow_none);
+
+ /* Try to dlopen the same DSO again, we expect this to fail again. */
+ if (!open_dso ("[Expected] "))
+ FAIL_EXIT1 ("We expect dlopen to fail at this point!.");
+
+ /* Add test_ldconfig directory to /etc/ld.so.conf. */
+ fp = xfopen (CONF, "w");
+ if (!(fwrite (DSO_DIR, 1, sizeof (DSO_DIR), fp)))
+ FAIL_EXIT1 ("updating /etc/ld.so.conf failed: %m");
+ xfclose (fp);
+
+ /* Try to dlopen the same DSO again, we expect this to still fail. */
+ if (!open_dso ("[Expected] "))
+ FAIL_EXIT1 ("We expect dlopen to fail at this point!.");
+
+ /* Run ldconfig again. */
+ result = support_capture_subprocess (execv_wrapper, args);
+ support_capture_subprocess_check (&result, "execv", 0, sc_allow_none);
+ support_capture_subprocess_free (&result);
+
+ if (open_dso ("[Unexpected] "))
+ FAIL_EXIT1 ("Dlopen failed.");
+
+ free (prog);
+ return 0;
+}
+
+#include <support/test-driver.c>
new file mode 100644
new file mode 100644
@@ -0,0 +1 @@
+cp $B/elf/tst-ldconfig-ld-mod.so $L/tst-ldconfig-ld-mod.so