This chapter describes the functions that various kernel components use to populate the procfs with files, symlinks, device nodes, and directories.
A minor note before we start: if you want to use any of the procfs functions, be sure to include the correct header file! This should be one of the first lines in your code:
#include <linux/proc_fs.h>
struct proc_dir_entry* create_proc_entry( | const char* | name, |
| mode_t | mode, | |
| struct proc_dir_entry* | parent); |
This function creates a regular file with the name
name, file mode
mode in the directory
parent. To create a file in the root of
the procfs, use NULL as
parent parameter. When successful, the
function will return a pointer to the freshly created
struct proc_dir_entry; otherwise it
will return NULL. Chapter 3, Communicating with userland describes how to do something useful with
regular files.
Note that it is specifically supported that you can pass a
path that spans multiple directories. For example
create_proc_entry("drivers/via0/info")
will create the via0
directory if necessary, with standard
0755 permissions.
If you only want to be able to read the file, the function
create_proc_read_entry described in the section called “Convenience functions” may be used to create and initialise
the procfs entry in one single call.