/**************************************************************************** * fs/vfs/fs_stat.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "inode/inode.h" #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifdef CONFIG_PSEUDOFS_SOFTLINKS /* Reset, preserving the number of symbolic links encountered so far */ # define RESET_BUF(b) \ { \ uint16_t save = (b)->st_count; \ memset((b), 0, sizeof(struct stat)); \ (b)->st_count = save; \ } #else /* Reset everything */ # define RESET_BUF(b) memset((b), 0, sizeof(struct stat)); #endif /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int stat_recursive(FAR const char *path, FAR struct stat *buf, int resolve); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: stat_recursive * * Returned Value: * Zero on success; < 0 on failure: * * EACCES Search permission is denied for one of the directories in the * path prefix of path. * EFAULT Bad address. * ENOENT A component of the path path does not exist, or the path is an * empty string. * ENOMEM Out of memory * ENOTDIR A component of the path is not a directory. * ****************************************************************************/ static int stat_recursive(FAR const char *path, FAR struct stat *buf, int resolve) { struct inode_search_s desc; FAR struct inode *inode; int ret; /* Get an inode for this path */ SETUP_SEARCH(&desc, path, true); ret = inode_find(&desc); if (ret < 0) { /* This name does not refer to an inode in the pseudo file system and * there is no mountpoint that includes in this path. */ goto errout_with_search; } /* Get the search results */ inode = desc.node; DEBUGASSERT(inode != NULL); /* The way we handle the stat depends on the type of inode that we * are dealing with. */ #ifndef CONFIG_DISABLE_MOUNTPOINT if (INODE_IS_MOUNTPT(inode)) { /* The node is a file system mointpoint. Verify that the mountpoint * supports the stat() method */ if (inode->u.i_mops && inode->u.i_mops->stat) { /* Perform the stat() operation */ ret = inode->u.i_mops->stat(inode, desc.relpath, buf); } } else #endif { /* The node is part of the root pseudo file system. This path may * recurse if soft links are supported in the pseudo file system. */ ret = inode_stat(inode, buf, resolve); } inode_release(inode); errout_with_search: RELEASE_SEARCH(&desc); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: nx_stat * * Description: * nx_stat() is similar to the standard 'stat' interface except that is * not a cancellation point and it does not modify the errno variable. * * nx_stat() is an internal NuttX interface and should not be called from * applications. * * Returned Value: * Zero is returned on success; a negated value is returned on any failure. * ****************************************************************************/ int nx_stat(FAR const char *path, FAR struct stat *buf, int resolve) { /* Sanity checks */ if (path == NULL || buf == NULL) { return -EFAULT; } if (*path == '\0') { return -ENOENT; } /* The perform the stat() operation on the path. This is potentially * recursive if soft link support is enabled. */ #ifdef CONFIG_PSEUDOFS_SOFTLINKS buf->st_count = 0; #endif return stat_recursive(path, buf, resolve); } /**************************************************************************** * Name: stat * * Returned Value: * Zero on success; -1 on failure with errno set: * * EACCES Search permission is denied for one of the directories in the * path prefix of path. * EFAULT Bad address. * ENOENT A component of the path path does not exist, or the path is an * empty string. * ENOMEM Out of memory * ENOTDIR A component of the path is not a directory. * ****************************************************************************/ int stat(FAR const char *path, FAR struct stat *buf) { int ret; ret = nx_stat(path, buf, 1); if (ret < 0) { set_errno(-ret); ret = ERROR; } return ret; } int lstat(FAR const char *path, FAR struct stat *buf) { int ret; ret = nx_stat(path, buf, 0); if (ret < 0) { set_errno(-ret); ret = ERROR; } return ret; } /**************************************************************************** * Name: inode_stat * * Description: * The inode_stat() function will obtain information about an 'inode' in * the pseudo file system and write it to the area pointed to by 'buf'. * * The 'buf' argument is a pointer to a stat structure, as defined in * , into which information is placed concerning the file. * * Input Parameters: * inode - The inode of interest * buf - The caller provide location in which to return information * about the inode. * resolve - Whether to resolve the symbolic link * * Returned Value: * Zero (OK) returned on success. Otherwise, a negated errno value is * returned to indicate the nature of the failure. * ****************************************************************************/ int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve) { DEBUGASSERT(inode != NULL && buf != NULL); /* Most of the stat entries just do not apply */ RESET_BUF(buf); /* Handle "special" nodes */ if (INODE_IS_SPECIAL(inode)) { #if defined(CONFIG_FS_NAMED_SEMAPHORES) /* Check for a named semaphore */ if (INODE_IS_NAMEDSEM(inode)) { buf->st_mode = S_IFSEM; } else #endif #if !defined(CONFIG_DISABLE_MQUEUE) /* Check for a message queue */ if (INODE_IS_MQUEUE(inode)) { buf->st_mode = S_IFMQ; } else #endif #if defined(CONFIG_FS_SHM) /* Check for shared memory */ if (INODE_IS_SHM(inode)) { buf->st_mode = S_IFSHM; } else #endif #if defined(CONFIG_MTD) /* Check for an MTD driver */ if (INODE_IS_MTD(inode)) { struct mtd_geometry_s mtdgeo; buf->st_mode = S_IFMTD; buf->st_mode |= S_IROTH | S_IRGRP | S_IRUSR; buf->st_mode |= S_IWOTH | S_IWGRP | S_IWUSR; if (inode->u.i_mtd != NULL && MTD_IOCTL(inode->u.i_mtd, MTDIOC_GEOMETRY, (unsigned long)((uintptr_t)&mtdgeo)) >= 0) { buf->st_size = mtdgeo.neraseblocks * mtdgeo.erasesize; } } else #endif #ifdef CONFIG_PSEUDOFS_SOFTLINKS /* Handle softlinks differently. Just call stat() recursively on the * target of the softlink. * * REVISIT: This has the possibility of an infinite loop! */ if (INODE_IS_SOFTLINK(inode)) { if (resolve) { int ret; /* Increment the link counter. This is necessary to avoid * infinite recursion if loops are encountered in the * traversal. If we encounter more SYMLOOP_MAX symbolic links * at any time during the traversal, error out. * * NOTE: That inode_search() will automatically skip over * consecutive, intermediate symbolic links. Those numbers * will not be included in the total. */ if (++buf->st_count > SYMLOOP_MAX) { return -ELOOP; } DEBUGASSERT(buf->st_count > 0); /* Check for unsigned integer overflow */ /* stat() the target of the soft link. */ ret = stat_recursive(inode->u.i_link, buf, 1); /* If stat() fails, then there is a problem with the target of * the symbolic link, but not with the symbolic link itself. * We should still report success, just with less information. */ if (ret < 0) { RESET_BUF(buf); } } else { /* Make sure the caller knows that this is a symbolic link. */ buf->st_mode = S_IRWXO | S_IRWXG | S_IRWXU | S_IFLNK; } } else #endif { } } /* Handle "normal inodes */ else if (inode->u.i_ops != NULL) { /* Determine read/write privileges based on the existence of read * and write methods. */ if (inode->u.i_ops->read) { buf->st_mode = S_IROTH | S_IRGRP | S_IRUSR; } if (inode->u.i_ops->write) { buf->st_mode |= S_IWOTH | S_IWGRP | S_IWUSR; } /* Determine the type of the inode */ /* Check for a mountpoint */ if (INODE_IS_MOUNTPT(inode)) { buf->st_mode |= S_IFDIR; } /* Check for a block driver */ else if (INODE_IS_BLOCK(inode)) { /* What is if also has child inodes? */ buf->st_mode |= S_IFBLK; #ifndef CONFIG_DISABLE_MOUNTPOINT if ((inode->u.i_bops != NULL) && (inode->u.i_bops->geometry != NULL)) { struct geometry geo; if (inode->u.i_bops->geometry(inode, &geo) >= 0 && geo.geo_available) { buf->st_size = geo.geo_nsectors * geo.geo_sectorsize; } } #endif } /* Otherwise, the node must refer to a character driver */ else /* if (INODE_IS_DRIVER(inode)) */ { /* What is it if it also has child inodes? */ buf->st_mode |= S_IFCHR; } } else { /* If it has no operations, then it must just be a intermediate * node in the inode tree. It is something like a directory. * We'll say that all pseudo-directories are read-able but not * write-able. */ buf->st_mode |= S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR; } return OK; }