[LTP] [PATCH] lib: Add library function for parsing kernel config
Cyril Hrubis
chrubis@suse.cz
Thu Nov 15 14:44:41 CET 2018
This is meant as last resort action for disabling tests if certain
kernel funcitonality was not present, in general case runtime checks are
prefered.
For functionality that can be build as a module tst_check_driver() is
most likely better fit since it will also insert requested kernel module
into kernel if needed.
For newly added syscalls kernel version comparsion and/or checking errno
is prefered.
However in rare cases certain core kernel functionality cannot be
detected in any other way than checking the kernel config, which is
where this API gets into the play.
The path to the kernel config could be specified by LTP_KCONFIG
environment variable, which also takes precedence before the
autodetection that attempts to read the config from known locations.
The required kernel options are passed as an array of strings via the
.needs_kconfigs pointer in the tst_test structure. The purpose of this
is twofold, one is that the test can disable itself at runtime if given
functionality is missing from kernel .config and second is about being
able to propagate this information to the testrunner (this could be done
once we figure out how export the information from the structure to the
test runner) then we can avoid running tests on unsuitable
configurations from the start.
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
CC: Pengfei Xu <pengfei.xu@intel.com>
CC: automated-testing@yoctoproject.org
---
doc/test-writing-guidelines.txt | 32 +++++++
include/tst_kconfig.h | 34 ++++++++
include/tst_test.h | 6 ++
lib/newlib_tests/.gitignore | 1 +
lib/newlib_tests/tst_kconfig.c | 24 ++++++
lib/tst_kconfig.c | 183 ++++++++++++++++++++++++++++++++++++++++
lib/tst_test.c | 4 +
7 files changed, 284 insertions(+)
create mode 100644 include/tst_kconfig.h
create mode 100644 lib/newlib_tests/tst_kconfig.c
create mode 100644 lib/tst_kconfig.c
diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
index d0b91c362..846c39532 100644
--- a/doc/test-writing-guidelines.txt
+++ b/doc/test-writing-guidelines.txt
@@ -1504,6 +1504,38 @@ static struct tst_test test = {
.save_restore = save_restore,
};
+2.2.28 Parsing kernel .config
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Generally testcases should attempt to autodetect as much kernel features as
+possible based on the currently running kernel. We do have tst_check_driver()
+to check if functionality that could be compiled as kernel module is present
+on the system, disabled syscalls can be detected by checking for 'ENOSYS'
+errno etc.
+
+However in rare cases core kernel features couldn't be detected based on the
+kernel userspace API and we have to resort on kernel .config parsing.
+
+For this cases the test should set the 'NULL' terminated needs_kconfig array
+of kernel config options required for the test. The test will exit with
+'TCONF' if any of the required options wasn't set to 'y' or 'm'.
+
+[source,c]
+-------------------------------------------------------------------------------
+#include "tst_test.h"
+
+static const char *kconfigs[] = {
+ "CONFIG_X86_INTEL_UMIP",
+ NULL
+};
+
+static struct tst_test test = {
+ ...
+ .needs_kconfigs = kconfigs,
+ ...
+};
+-------------------------------------------------------------------------------
+
2.3 Writing a testcase in shell
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/include/tst_kconfig.h b/include/tst_kconfig.h
new file mode 100644
index 000000000..daba808b0
--- /dev/null
+++ b/include/tst_kconfig.h
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+#ifndef TST_KCONFIG_H__
+#define TST_KCONFIG_H__
+
+/*
+ * Parses kernel config given a CONFIG_FOO symbol.
+ *
+ * The location of the config is detected automatically in case that the config
+ * lives in one of the standard locations or can be set/overrided by setting
+ * LTP_KCONFIG environment variable.
+ *
+ * The functions returns:
+ *
+ * 'y' -- when compiled in
+ * 'm' -- when compiled as a module
+ * 'v' -- when set to some value e.g. CONFIG_BLK_DEV_RAM_COUNT=16
+ * 'n' -- when not set
+ * 'u' -- when CONFIG_FOO wasn't present in CONFIG
+ * 'e' -- on error i.e. .config couldn't be located
+ */
+char tst_kconfig(const char *id);
+
+/*
+ * Exits the test with TCONF on first config option that is not set to 'm' or 'y'
+ *
+ * @kconfigs: NULL terminated array of kernel config options such as "CONFIG_MMU"
+ */
+void tst_kconfig_check(const char *const *kconfigs);
+
+#endif /* TST_KCONFIG_H__ */
diff --git a/include/tst_test.h b/include/tst_test.h
index 2ebf746eb..f21687c06 100644
--- a/include/tst_test.h
+++ b/include/tst_test.h
@@ -182,6 +182,12 @@ struct tst_test {
* before setup and restore after cleanup
*/
const char * const *save_restore;
+
+ /*
+ * NULL terminated array of kernel config options required for the
+ * test.
+ */
+ const char *const *needs_kconfigs;
};
/*
diff --git a/lib/newlib_tests/.gitignore b/lib/newlib_tests/.gitignore
index c702644f0..4052162bf 100644
--- a/lib/newlib_tests/.gitignore
+++ b/lib/newlib_tests/.gitignore
@@ -24,3 +24,4 @@ test19
tst_expiration_timer
test_exec
test_exec_child
+tst_kconfig
diff --git a/lib/newlib_tests/tst_kconfig.c b/lib/newlib_tests/tst_kconfig.c
new file mode 100644
index 000000000..855269366
--- /dev/null
+++ b/lib/newlib_tests/tst_kconfig.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+#include "tst_test.h"
+#include "tst_kconfig.h"
+
+static void do_test(void)
+{
+ tst_res(TPASS, "Not reached!");
+}
+
+static const char *kconfigs[] = {
+ "CONFIG_MMU",
+ "CONFIG_EXT4_FS",
+ /* Comment this to make the test run */
+ "CONFIG_NONEXISTENT",
+ NULL
+};
+
+static struct tst_test test = {
+ .test_all = do_test,
+ .needs_kconfigs = kconfigs,
+};
diff --git a/lib/tst_kconfig.c b/lib/tst_kconfig.c
new file mode 100644
index 000000000..348767b3d
--- /dev/null
+++ b/lib/tst_kconfig.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+#ifndef TST_KCONFIG_H__
+#define TST_KCONFIG_H__
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/utsname.h>
+
+#define TST_NO_DEFAULT_MAIN
+#include "tst_test.h"
+
+static const char *kconfig_path(char *path_buf, size_t path_buf_len)
+{
+ const char *path = getenv("LTP_KCONFIG");
+ struct utsname un;
+
+ if (path) {
+ if (!access(path, F_OK))
+ return path;
+
+ tst_res(TWARN, "LTP_KCONFIG='%s' does not exist", path);
+ }
+
+ if (!access("/proc/config.gz", F_OK))
+ return "/proc/config.gz";
+
+ uname(&un);
+
+ snprintf(path_buf, path_buf_len, "/boot/config-%s", un.release);
+
+ if (!access(path_buf, F_OK))
+ return path_buf;
+
+ tst_res(TINFO, "Couldn't locate kernel config!");
+
+ return NULL;
+}
+
+static char parse_line(const char *line)
+{
+ if (strstr(line, "=y"))
+ return 'y';
+
+ if (strstr(line, "=m"))
+ return 'm';
+
+ if (strstr(line, "="))
+ return 'v';
+
+ return 'n';
+}
+
+static char is_gzip;
+
+static FILE *open_kconfig(void)
+{
+ FILE *fp;
+ char buf[1024];
+ char path_buf[1024];
+ const char *path = kconfig_path(path_buf, sizeof(path_buf));
+
+ if (!path)
+ return NULL;
+
+ is_gzip = !!strstr(path, ".gz");
+
+ if (is_gzip) {
+ snprintf(buf, sizeof(buf), "zcat '%s'", path);
+ fp = popen(buf, "r");
+ } else {
+ fp = fopen(path, "r");
+ }
+
+ if (!fp)
+ tst_brk(TBROK | TERRNO, "Failed to open '%s'", path);
+
+ return fp;
+}
+
+static void close_kconfig(FILE *fp)
+{
+ if (is_gzip)
+ pclose(fp);
+ else
+ fclose(fp);
+}
+
+static int match_option(const char *line, const char *opt)
+{
+ size_t opt_len = strlen(opt);
+
+ return !strncmp(line, opt, opt_len) &&
+ (line[opt_len] == '=' || line[opt_len] == ' ');
+}
+
+char tst_kconfig(const char *id)
+{
+ char buf[1024];
+ char match = 'u';
+ FILE *fp;
+
+ fp = open_kconfig();
+ if (!fp)
+ return 'e';
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ if (match_option(buf, id)) {
+ match = parse_line(buf);
+ break;
+ }
+ }
+
+ close_kconfig(fp);
+
+ return match;
+}
+
+static unsigned int array_len(const char *const *kconfigs)
+{
+ unsigned int i = 0;
+
+ while (kconfigs[i])
+ i++;
+
+ return i;
+}
+
+void tst_kconfig_check(const char *const *kconfigs)
+{
+ char buf[1024];
+ FILE *fp;
+ unsigned int conf_cnt = array_len(kconfigs);
+ unsigned int conf_match[conf_cnt];
+ unsigned int i, j;
+
+ memset(conf_match, 0, sizeof(conf_match));
+
+ fp = open_kconfig();
+ if (!fp)
+ tst_brk(TBROK, "Cannot parse kernel .config");
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ for (i = 0; i < conf_cnt; i++) {
+ if (conf_match[i])
+ continue;
+
+ if (match_option(buf, kconfigs[i]) &&
+ (strstr(buf, "=y") || strstr(buf, "=m"))) {
+ conf_match[i] = 1;
+
+ for (j = 0; j < conf_cnt; j++) {
+ if (!conf_match[j])
+ break;
+ }
+
+ if (j == i)
+ goto exit;
+ }
+ }
+
+ }
+
+ int abort_test = 0;
+
+ for (i = 0; i < conf_cnt; i++) {
+ if (!conf_match[i]) {
+ abort_test = 1;
+ tst_res(TINFO, "Kernel is missing %s", kconfigs[i]);
+ }
+ }
+
+ if (abort_test)
+ tst_brk(TCONF, "Aborting test due to missing kernel config options!");
+
+exit:
+ close_kconfig(fp);
+}
+
+#endif /* TST_KCONFIG_H__ */
diff --git a/lib/tst_test.c b/lib/tst_test.c
index 661fbbfce..da3e0c8a0 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -36,6 +36,7 @@
#include "tst_clocks.h"
#include "tst_timer.h"
#include "tst_sys_conf.h"
+#include "tst_kconfig.h"
#include "old_resource.h"
#include "old_device.h"
@@ -770,6 +771,9 @@ static void do_setup(int argc, char *argv[])
if (tst_test->tconf_msg)
tst_brk(TCONF, "%s", tst_test->tconf_msg);
+ if (tst_test->needs_kconfigs)
+ tst_kconfig_check(tst_test->needs_kconfigs);
+
assert_test_fn();
tid = get_tid(argv);
--
2.16.4
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