ext2文件系统源代码之xattr_trusted.c

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我们来看下xattr_trusted.c这个文件的代码

/* * linux/fs/ext2/xattr_trusted.c * 信任的扩展属性处理代码 * * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org> */#include <linux/module.h>#include <linux/string.h>#include <linux/capability.h>#include <linux/fs.h>#include <linux/ext2_fs.h>#include "xattr.h"/*属性名前缀*/#define XATTR_TRUSTED_PREFIX "trusted."/*得到带前缀的属性名称，返回名称长度，list存放全名*/static size_text2_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,const char *name, size_t name_len){/*前缀名长度和总长度*/const int prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;const size_t total_len = prefix_len + name_len + 1;/*权限*/if (!capable(CAP_SYS_ADMIN))return 0;if (list && total_len <= list_size) {/*先复制前缀名，再复制后边名字*/memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);memcpy(list+prefix_len, name, name_len);list[prefix_len + name_len] = '\0';}return total_len;}/*得到想要的属性*/static intext2_xattr_trusted_get(struct inode *inode, const char *name,       void *buffer, size_t size){/*参数检查*/if (strcmp(name, "") == 0)return -EINVAL;/*调用之前讲过的函数来得到属性*/return ext2_xattr_get(inode, EXT2_XATTR_INDEX_TRUSTED, name,      buffer, size);}static intext2_xattr_trusted_set(struct inode *inode, const char *name,       const void *value, size_t size, int flags){/*参数检查*/if (strcmp(name, "") == 0)return -EINVAL;/*调用之前讲过的函数来设置属性*/return ext2_xattr_set(inode, EXT2_XATTR_INDEX_TRUSTED, name,      value, size, flags);}/*trusted属性处理函数结构体*/struct xattr_handler ext2_xattr_trusted_handler = {.prefix= XATTR_TRUSTED_PREFIX,.list= ext2_xattr_trusted_list,.get= ext2_xattr_trusted_get,.set= ext2_xattr_trusted_set,};

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