Hello, I was trying to write a kernel module, but when I compile I get many errors in proc_fs.h file. please have a look at following code, I tried to compile on redhat 7.3 with kernel 2.4.18-3. I tried to compile with following command :- gcc -O2 -D__KERNEL__ -DMODULE -I/usr/src/linux2.4.18-3 -c helloworld_proc_module.c -o helloworld_proc_module.o Thanks in advance for the reply. /* /* * helloworld_proc_module.c is based on procfs_example.c by Erik Mouw. * For more information, please see The Linux Kernel Procfs Guide, * http://kernelnewbies.org/documents/kdoc/procfs-guide/lkprocfsguide.html */ /* helloworld_proc_module * helloworld_proc_module demonstrates the use of a /proc directory entry. * The init function, init_helloworld, creates /proc/helloworld and * populates its data, read_proc, write_proc and owner fields. The exit * function, cleanup_helloworld, removes the /proc/helloworld entry. * The proc_read function, proc_read_helloworld, is called whenever * a file read operation occurs on /proc/helloworld. The * proc_write function, proc_write_helloworld, is called whenever a file * file write operation occurs on /proc/helloworld. * * To demonstrate read and write operations, this module uses data * structure called helloworld_data containing a char field called value. * Read and write operations on /proc/helloworld manipulate * helloworld_data->value. The init function sets value = 'Default'. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/proc_fs.h> #include <asm/uaccess.h> #define MODULE_VERSION "1.0" #define MODULE_NAME "helloworld proc module" /* this is how long our data->value char array can be */ #define HW_LEN 8 struct helloworld_data_t { char value[HW_LEN + 1]; }; static struct proc_dir_entry *helloworld_file; struct helloworld_data_t helloworld_data; /* proc_read - proc_read_helloworld * proc_read_helloworld is the callback function that the kernel calls when * there's a read file operation on the /proc file (for example, * cat /proc/helloworld). The file's data pointer (&helloworld_data) is * passed in the data parameter. You first cast it to the helloworld_data_t * structure. This proc_read function then uses the sprintf function to * create a string that is pointed to by the page pointer. The function then * returns the length of page. Because helloworld_data->value is set to * "Default", the command cat /proc/helloworld should return * helloworld Default */ static int proc_read_helloworld(char *page, char **start, off_t off, int count, int *eof, void *data) { int len; /* cast the void pointer of data to helloworld_data_t*/ struct helloworld_data_t *helloworld_data=(struct helloworld_data_t *)data; /* use sprintf to fill the page array with a string */ len = sprintf(page, "helloworld %s\n", helloworld_data->value); return len; } /* proc_write - proc_write_helloworld * proc_write_helloworld is the callback function that the kernel calls * when there's a write file operation on the /proc file, (for example, * echo test > /proc/helloworld). The file's data pointer * (&helloworld_data) is passed in the data parameter. You first cast it to * the helloworld_data_t structure. The page parameter points to the * incoming data. You use the copy_from_user function to copy the page * contents to the data->value field. Before you do that, though, you check * the page length, which is stored in count to ensure that you don't * overrun the length of data->value. This function then returns the length * of the data copied. */ static int proc_write_helloworld(struct file *file, const char *page, unsigned long count, void *data) { int len; /* cast the void pointer of data to helloworld_data_t*/ struct helloworld_data_t *helloworld_data=(struct helloworld_data_t *)data; /* do a range checking, don't overflow buffers in kernel modules */ if(count > HW_LEN) len = HW_LEN; else len = count; /* use the copy_from_user function to copy page data to * to our helloworld_data->value */ if(copy_from_user(helloworld_data->value, page, len)) { return -EFAULT; } /* zero terminate helloworld_data->value */ helloworld_data->value[len] = '\0'; return len; } /* init - init_helloworld * init_helloworld creates the /proc/helloworld entry file and obtains its * pointer called helloworld_file. The helloworld_file fields, data, * read_proc, write_proc and owner, are filled. init_helloworld completes * by writing an entry to the system log using printk. */ static int __init init_helloworld(void) { int rv = 0; /* Create the proc entry and make it readable and writeable by all - 0666 */ helloworld_file = create_proc_entry("helloworld", 0666, NULL); if(helloworld_file == NULL) { return -ENOMEM; } /* set the default value of our data to Default. This way a read operation on * /proc/helloworld will return something. */ strcpy(helloworld_data.value, "Default"); /* Set helloworld_file fields */ helloworld_file->data = &helloworld_data; helloworld_file->read_proc = &proc_read_helloworld; helloworld_file->write_proc = &proc_write_helloworld; helloworld_file->owner = THIS_MODULE; /* everything initialized */ printk(KERN_INFO "%s %s initialized\n",MODULE_NAME, MODULE_VERSION); return 0; } /* exit - cleanup_helloworld * cleanup_helloworld removes the /proc file entry helloworld and * prints a message to the system log. */ static void __exit cleanup_helloworld(void) { remove_proc_entry("helloworld", NULL); printk(KERN_INFO "%s %s removed\n", MODULE_NAME, MODULE_VERSION); } /* here are the compiler macros for module operation */ module_init(init_helloworld); module_exit(cleanup_helloworld); MODULE_AUTHOR("Craig Hollabaugh"); MODULE_DESCRIPTION("helloworld proc module"); MODULE_LICENSE("GPL"); EXPORT_NO_SYMBOLS; any help will be greatly appreciated.. thanks, -hemanshu _______________________________________________ Redhat-devel-list mailing list Redhat-devel-list@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/redhat-devel-list
