docs: add a paragraph about access() to Common Problems section
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
index 91edbf0..eea1bf6 100644
--- a/doc/test-writing-guidelines.txt
+++ b/doc/test-writing-guidelines.txt
@@ -883,6 +883,14 @@
file permissions you need to 'chmod()' the file afterwards or use SAFE_TOUCH()
that does the 'chmod()' for you.
+3.2 access()
+~~~~~~~~~~~
+
+If 'access(some_file, W_OK)' is executed by root it will return success even
+if the file doesn't have write permission bits set (the same holds for R_OK
+too). For sysfs files you can use 'open()' as a workaround to check file's
+read/write permissions. It might not work for other filesystems, for these you
+have to use 'stat()', 'lstat()' or 'fstat()'.
4. Test Contribution Checklist
------------------------------