/**************************************************************************** * fs/vfs/fs_stat.c * * Copyright (C) 2007-2009, 2012, 2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "inode/inode.h" /**************************************************************************** * 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 inline int statpseudo(FAR struct inode *inode, FAR struct stat *buf); static inline int statroot(FAR struct stat *buf); int stat_recursive(FAR const char *path, FAR struct stat *buf); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: statpseudo ****************************************************************************/ static inline int statpseudo(FAR struct inode *inode, FAR struct stat *buf) { /* Most of the stat entries just do not apply */ RESET_BUF(buf); if (INODE_IS_SPECIAL(inode)) { #if defined(CONFIG_FS_NAMED_SEMAPHORES) if (INODE_IS_NAMEDSEM(inode)) { buf->st_mode = S_IFSEM; } else #endif #if !defined(CONFIG_DISABLE_MQUEUE) if (INODE_IS_MQUEUE(inode)) { buf->st_mode = S_IFMQ; } else #endif #if defined(CONFIG_FS_SHM) if (INODE_IS_SHM(inode)) */ { buf->st_mode = S_IFSHM; } 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)) { int ret; /* Increment the link counter. This is necesssary to avoid * infinite recursion if loops are encountered in the traversal. * If we encounter more SYMLOOP_MAX symbolic links at any time * during the travrsal, 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((FAR const char *)inode->u.i_link, buf); /* 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); } /* Make sure that the caller knows that this really a symbolic link. */ buf->st_mode |= S_IFLNK; } else #endif { } } 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 */ if (INODE_IS_MOUNTPT(inode)) { buf->st_mode |= S_IFDIR; } else if (INODE_IS_BLOCK(inode)) { /* What is if also has child inodes? */ buf->st_mode |= S_IFBLK; } 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; } /**************************************************************************** * Name: statroot ****************************************************************************/ static inline int statroot(FAR struct stat *buf) { /* There is no inode associated with the fake root directory */ RESET_BUF(buf); buf->st_mode = S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR; return OK; } /**************************************************************************** * Name: stat_recursive * * 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_recursive(FAR const char *path, FAR struct stat *buf) { 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 a psudeo-inode and there is no * mountpoint that includes in this path. */ ret = -ret; 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 = statpseudo(inode, buf); } /* Check if the stat operation was successful */ if (ret < 0) { ret = -ret; goto errout_with_inode; } /* Successfully stat'ed the file */ inode_release(inode); RELEASE_SEARCH(&desc); return OK; /* Failure conditions always set the errno appropriately */ errout_with_inode: inode_release(inode); errout_with_search: RELEASE_SEARCH(&desc); set_errno(ret); return ERROR; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * 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; /* Sanity checks */ if (path == NULL || buf == NULL) { ret = EFAULT; goto errout; } if (*path == '\0') { ret = ENOENT; goto errout; } /* Check for the fake root directory (which has no inode) */ if (strcmp(path, "/") == 0) { return statroot(buf); } /* 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); errout: set_errno(ret); return ERROR; }