Linux-driven Learning-Create a directory sample below/sys

Sometimes we need to create some directories under/sys, and here's an example. After the driver module is loaded, a directory named Sysfs_demo is created below/sys and in which several files and directories are created.

ls -r/sys/sysfs_demo//sys/sysfs_demo/: Node_one      node_two      sysfs_demo_2/sys/sysfs_demo/ sysfs_demo_2:node_four   Node_three

The two functions used here are: Kobject_create_and_add and Sysfs_create_group. The previous function is used to create a directory under/sys, and the latter function is used to create the file.

Example driver:

1 #definePR_FMT (FMT) kbuild_modname ":%s:" FMT, __func__2 3#include <linux/init.h>4#include <linux/module.h>5#include <linux/kobject.h>6#include <linux/device.h>7 8 Static structKobject *k_obj =NULL;9 Static structKobject *k_obj_2 =NULL;Ten  One Static Charnode_one_buf[ -] = {0}; A  - Staticssize_t Sysfs_demo_show_node_one (structKobject *kobj,structKobj_attribute *attr,Char*buf) - { thePr_info ("Enter, node:%s\n", attr->attr.name); -     returnsprintf (BUF,"%s:%s\n", attr->Attr.name, node_one_buf); - } -  + Staticssize_t Sysfs_demo_store_node_one (structKobject *kobj,structKobj_attribute *attr,Const Char*buf, size_t N) - { +Pr_info ("Enter, node:%s\n", attr->attr.name); A  atsprintf (Node_one_buf,"%s", buf); -  -     returnN; - } -  - Static structKobj_attribute Node_one_attribute = in__attr (Node_one, s_iwusr|S_irugo, Sysfs_demo_show_node_one, sysfs_demo_store_node_one); -  to Staticssize_t Sysfs_demo_show_node_two (structKobject *kobj,structKobj_attribute *attr,Char*buf) + { -  the     returnsprintf (BUF,"%s\n", attr->attr.name); * } $ Panax Notoginseng Static structKobj_attribute Node_two_attribute = -__attr (Node_two, s_iwusr|S_irugo, Sysfs_demo_show_node_two, NULL); the  + Static structAttribute *sysfs_demo_attributes[] = { A&Node_one_attribute.attr, the&Node_two_attribute.attr, + NULL - }; $  $ Static Const structAttribute_group Sysfs_demo_attr_group = { -. Attrs =Sysfs_demo_attributes, - }; the  - Static Charnode_three_buf[ -] = {0};Wuyi  the Staticssize_t Sysfs_demo_show_node_three (structKobject *kobj,structKobj_attribute *attr,Char*buf) - { WuPr_info ("Enter, node:%s\n", attr->attr.name); -     returnsprintf (BUF,"%s:%s\n", attr->Attr.name, node_three_buf); About } $  - Staticssize_t Sysfs_demo_store_node_three (structKobject *kobj,structKobj_attribute *attr,Const Char*buf, size_t N) - { -Pr_info ("Enter, node:%s\n", attr->attr.name); A  +sprintf (Node_three_buf,"%s", buf); the  -     returnN; $ } the  the Static structKobj_attribute Node_three_attribute = the__attr (Node_three, s_iwusr|S_irugo, Sysfs_demo_show_node_three, sysfs_demo_store_node_three); the  - Staticssize_t Sysfs_demo_show_node_four (structKobject *kobj,structKobj_attribute *attr,Char*buf) in { the  the     returnsprintf (BUF,"%s\n", attr->attr.name); About } the  the Static structKobj_attribute Node_four_attribute = the__attr (Node_four, s_iwusr|S_irugo, Sysfs_demo_show_node_four, NULL); +  - Static structAttribute *sysfs_demo2_attributes[] = { the&Node_three_attribute.attr,Bayi&Node_four_attribute.attr, the NULL the }; -  - Static Const structAttribute_group Sysfs_demo2_attr_group = { the. Attrs =Sysfs_demo2_attributes, the }; the  the Static int__init Sysfs_demo_init (void) - { the     if(K_obj = Kobject_create_and_add ("Sysfs_demo", NULL)) = =NULL) { thePr_err ("Sysfs_demo sys node create error \ n"); the         Goto  out;94     } the  the     if(Sysfs_create_group (K_obj, &Sysfs_demo_attr_group)) { thePr_err ("Sysfs_create_group failed\n");98         GotoOut2; About     } - 101     if(K_obj_2 = Kobject_create_and_add ("sysfs_demo_2", k_obj)) = =NULL) {102Pr_err ("hwinfo sys node create error \ n");103         Gotoout3;104     } the 106     if(Sysfs_create_group (K_obj_2, &Sysfs_demo2_attr_group)) {107Pr_err ("Sysfs_create_group failed\n");108         GotoOut4;109     } the 111Pr_info ("enter.\n"); the     return 0;113 Out4: the Kobject_put (k_obj_2); the OUT3: theSysfs_remove_group (K_obj, &sysfs_demo_attr_group);117 Out2:118 Kobject_put (k_obj);119  out: -     return-1;121 }122 Module_init (sysfs_demo_init);123 124 Static void__exit Sysfs_demo_exit (void) the {126Pr_info ("enter.\n");127  -     if(k_obj) {129Sysfs_remove_group (K_obj, &sysfs_demo_attr_group); the         if(k_obj_2) {131Sysfs_remove_group (K_obj_2, &sysfs_demo2_attr_group); the Kobject_put (k_obj_2);133         }134 Kobject_put (k_obj);135     }136 137 }138 Module_exit (sysfs_demo_exit);139  $Module_license ("GPL");

Linux-driven Learning-Create a directory sample below/sys