/* * debugfs.c - ACPI debugfs interface to userspace. */ #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/uaccess.h> #include <linux/debugfs.h> #include <acpi/acpi_drivers.h> #include "internal.h" #define _COMPONENT ACPI_SYSTEM_COMPONENT ACPI_MODULE_NAME("custom_method"); MODULE_LICENSE("GPL"); static struct dentry *cm_dentry; /* /sys/kernel/debug/acpi/custom_method */ static ssize_t cm_write(struct file *file, const char __user * user_buf, size_t count, loff_t *ppos) { static char *buf; static u32 max_size; static u32 uncopied_bytes; struct acpi_table_header table; acpi_status status; if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) return -EINVAL; if (copy_from_user(&table, user_buf, sizeof(struct acpi_table_header))) return -EFAULT; uncopied_bytes = max_size = table.length; buf = kzalloc(max_size, GFP_KERNEL); if (!buf) return -ENOMEM; } if (buf == NULL) return -EINVAL; if ((*ppos > max_size) || (*ppos + count > max_size) || (*ppos + count < count) || (count > uncopied_bytes)) return -EINVAL; if (copy_from_user(buf + (*ppos), user_buf, count)) { kfree(buf); buf = NULL; return -EFAULT; } uncopied_bytes -= count; *ppos += count; if (!uncopied_bytes) { status = acpi_install_method(buf); kfree(buf); buf = NULL; if (ACPI_FAILURE(status)) return -EINVAL; add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); } return count; } static const struct file_operations cm_fops = { .write = cm_write, .llseek = default_llseek, }; static int __init acpi_custom_method_init(void) { if (acpi_debugfs_dir == NULL) return -ENOENT; cm_dentry = debugfs_create_file("custom_method", S_IWUSR, acpi_debugfs_dir, NULL, &cm_fops); if (cm_dentry == NULL) return -ENODEV; return 0; } static void __exit acpi_custom_method_exit(void) { if (cm_dentry) debugfs_remove(cm_dentry); } module_init(acpi_custom_method_init); module_exit(acpi_custom_method_exit);