[lttng-dev] [PATCH RFC lttng-modules] Fix: lttng-test build failure for kernels < 3.0

[Michael Jeanson]

Fixes an undefined reference to kstrtouint_from_user.

The provided wrapper is just an example and should be carefully reviewed and
probably reimplemented from scratch considering my proficiency in kernel c.

Signed-off-by: Michael Jeanson <mjeanson at efficios.com>
---
 probes/lttng-test.c |  3 ++-
 wrapper/kstrtox.h   | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 wrapper/kstrtox.h

diff --git a/probes/lttng-test.c b/probes/lttng-test.c
index 2a66f45..bd9f5f8 100644
--- a/probes/lttng-test.c
+++ b/probes/lttng-test.c
@@ -28,6 +28,7 @@
 #include "../lttng-events.h"
 #include "../lttng-tracer.h"
 #include "../wrapper/tracepoint.h"
+#include "../wrapper/kstrtox.h"
 
 #define TP_MODULE_NOAUTOLOAD
 #define LTTNG_PACKAGE_BUILD
@@ -76,7 +77,7 @@ ssize_t lttng_test_filter_event_write(struct file *file, const char __user *user
 	int ret;
 
 	/* Get the number of iterations */
-	ret = kstrtouint_from_user(user_buf, count, 10, &nr_iter);
+	ret = lttng_kstrtouint_from_user(user_buf, count, 10, &nr_iter);
 	if (ret) {
 		written = ret;
 		goto end;
diff --git a/wrapper/kstrtox.h b/wrapper/kstrtox.h
new file mode 100644
index 0000000..e0c10cf
--- /dev/null
+++ b/wrapper/kstrtox.h
@@ -0,0 +1,54 @@
+#ifndef _LTTNG_WRAPPER_KSTRTOX_H
+#define _LTTNG_WRAPPER_KSTRTOX_H
+
+/*
+ * wrapper/vzalloc.h
+ *
+ * Copyright (C) 2015 Michael Jeanson <mjeanson at efficios.com>
+ *
+ * This 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; only
+ * version 2.1 of the License.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/version.h>
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(3,0,0))
+static inline
+int __must_check lttng_kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res)
+{
+	int ret;
+	unsigned int tmp;
+	char kbuf[count], *endptr;
+
+	ret = copy_from_user(kbuf, s, count);
+	if (ret)
+		return ret;
+
+	&tmp = simple_strtoul(kbuf, &endptr, base);
+	if (!*endptr)
+		return -EINVAL;
+
+	*res = tmp;
+	return 0;
+}
+#else
+static inline
+int __must_check lttng_kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res)
+{
+	return kstrtouint_from_user(s, count, base, res);
+}
+#endif
+
+
+#endif /* _LTTNG_WRAPPER_KSTRTOX_H */
-- 
1.9.1