blob: 4be4f5fbe6d511df2962c305beb7145fe0541707 [file] [log] [blame]
/*
* 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.
*/
#include <assert.h>
#include <string.h>
#include <nffs/nffs.h>
#include <nffs/os.h>
static struct nffs_file *
nffs_file_alloc(void)
{
struct nffs_file *file;
file = nffs_os_mempool_get(&nffs_file_pool);
if (file != NULL) {
memset(file, 0, sizeof *file);
}
return file;
}
static int
nffs_file_free(struct nffs_file *file)
{
int rc;
if (file != NULL) {
rc = nffs_os_mempool_free(&nffs_file_pool, file);
if (rc != 0) {
return FS_EOS;
}
}
return 0;
}
/**
* Creates a new empty file and writes it to the file system. If a file with
* the specified path already exists, the behavior is undefined.
*
* @param parent The parent directory to insert the new file in.
* @param filename The name of the file to create.
* @param filename_len The length of the filename, in characters.
* @param is_dir 1 if this is a directory; 0 if it is a normal
* file.
* @param out_inode_entry On success, this points to the inode
* corresponding to the new file.
*
* @return 0 on success; nonzero on failure.
*/
int
nffs_file_new(struct nffs_inode_entry *parent, const char *filename,
uint8_t filename_len, int is_dir,
struct nffs_inode_entry **out_inode_entry)
{
struct nffs_disk_inode disk_inode;
struct nffs_inode_entry *inode_entry;
uint32_t offset;
uint8_t area_idx;
int rc;
rc = nffs_inode_entry_reserve(&inode_entry);
if (rc != 0) {
goto err;
}
rc = nffs_misc_reserve_space(sizeof disk_inode + filename_len,
&area_idx, &offset);
if (rc != 0) {
goto err;
}
memset(&disk_inode, 0, sizeof disk_inode);
if (is_dir) {
disk_inode.ndi_id = nffs_hash_next_dir_id++;
} else {
disk_inode.ndi_id = nffs_hash_next_file_id++;
}
disk_inode.ndi_seq = 0;
disk_inode.ndi_lastblock_id = NFFS_ID_NONE;
if (parent == NULL) {
disk_inode.ndi_parent_id = NFFS_ID_NONE;
} else {
disk_inode.ndi_parent_id = parent->nie_hash_entry.nhe_id;
}
disk_inode.ndi_filename_len = filename_len;
disk_inode.ndi_flags = 0;
nffs_crc_disk_inode_fill(&disk_inode, filename);
rc = nffs_inode_write_disk(&disk_inode, filename, area_idx, offset);
if (rc != 0) {
goto err;
}
inode_entry->nie_hash_entry.nhe_id = disk_inode.ndi_id;
inode_entry->nie_hash_entry.nhe_flash_loc =
nffs_flash_loc(area_idx, offset);
inode_entry->nie_refcnt = 1;
inode_entry->nie_last_block_entry = NULL;
if (parent != NULL) {
rc = nffs_inode_add_child(parent, inode_entry);
if (rc != 0) {
goto err;
}
} else {
assert(disk_inode.ndi_id == NFFS_ID_ROOT_DIR);
nffs_inode_setflags(inode_entry, NFFS_INODE_FLAG_INTREE);
}
nffs_hash_insert(&inode_entry->nie_hash_entry);
*out_inode_entry = inode_entry;
return 0;
err:
nffs_inode_entry_free(inode_entry);
return rc;
}
/**
* Performs a file open operation.
*
* @param out_file On success, a pointer to the newly-created file
* handle gets written here.
* @param path The path of the file to open.
* @param access_flags Flags controlling file access; see nffs_open() for
* details.
*
* @return 0 on success; nonzero on failure.
*/
int
nffs_file_open(struct nffs_file **out_file, const char *path,
uint8_t access_flags)
{
struct nffs_path_parser parser;
struct nffs_inode_entry *parent;
struct nffs_inode_entry *inode;
struct nffs_file *file;
int rc;
file = NULL;
/* Reject invalid access flag combinations. */
if (!(access_flags & (FS_ACCESS_READ | FS_ACCESS_WRITE))) {
rc = FS_EINVAL;
goto err;
}
if (access_flags & (FS_ACCESS_APPEND | FS_ACCESS_TRUNCATE) &&
!(access_flags & FS_ACCESS_WRITE)) {
rc = FS_EINVAL;
goto err;
}
if (access_flags & FS_ACCESS_APPEND &&
access_flags & FS_ACCESS_TRUNCATE) {
rc = FS_EINVAL;
goto err;
}
file = nffs_file_alloc();
if (file == NULL) {
rc = FS_ENOMEM;
goto err;
}
nffs_path_parser_new(&parser, path);
rc = nffs_path_find(&parser, &inode, &parent);
if (rc == FS_ENOENT && parser.npp_token_type == NFFS_PATH_TOKEN_LEAF) {
/* The path is valid, but the file does not exist. This is an error
* for read-only opens.
*/
if (!(access_flags & FS_ACCESS_WRITE)) {
goto err;
}
/* Make sure the parent directory exists. */
if (parent == NULL) {
goto err;
}
/* Create a new file at the specified path. */
rc = nffs_file_new(parent, parser.npp_token, parser.npp_token_len, 0,
&file->nf_inode_entry);
if (rc != 0) {
goto err;
}
} else if (rc == 0) {
/* The file already exists. */
/* Reject an attempt to open a directory. */
if (nffs_hash_id_is_dir(inode->nie_hash_entry.nhe_id)) {
rc = FS_EINVAL;
goto err;
}
if (access_flags & FS_ACCESS_TRUNCATE) {
/* The user is truncating the file. Unlink the old file and create
* a new one in its place.
*/
nffs_path_unlink(path);
rc = nffs_file_new(parent, parser.npp_token, parser.npp_token_len,
0, &file->nf_inode_entry);
if (rc != 0) {
goto err;
}
} else {
/* The user is not truncating the file. Point the file handle to
* the existing inode.
*/
file->nf_inode_entry = inode;
}
} else {
/* Invalid path. */
goto err;
}
if (access_flags & FS_ACCESS_APPEND) {
rc = nffs_inode_data_len(file->nf_inode_entry, &file->nf_offset);
if (rc != 0) {
goto err;
}
} else {
file->nf_offset = 0;
}
nffs_inode_inc_refcnt(file->nf_inode_entry);
file->nf_access_flags = access_flags;
*out_file = file;
return 0;
err:
nffs_file_free(file);
return rc;
}
/**
* Positions a file's read and write pointer at the specified offset. The
* offset is expressed as the number of bytes from the start of the file (i.e.,
* seeking to 0 places the pointer at the first byte in the file).
*
* @param file The file to reposition.
* @param offset The offset from the start of the file to seek to.
*
* @return 0 on success; nonzero on failure.
*/
int
nffs_file_seek(struct nffs_file *file, uint32_t offset)
{
uint32_t len;
int rc;
rc = nffs_inode_data_len(file->nf_inode_entry, &len);
if (rc != 0) {
return rc;
}
if (offset > len) {
return FS_EOFFSET;
}
file->nf_offset = offset;
return 0;
}
/**
* Reads data from the specified file. If more data is requested than remains
* in the file, all available data is retrieved. Note: this type of short read
* results in a success return code.
*
* @param file The file to read from.
* @param len The number of bytes to attempt to read.
* @param out_data The destination buffer to read into.
* @param out_len On success, the number of bytes actually read gets
* written here. Pass null if you don't care.
*
* @return 0 on success; nonzero on failure.
*/
int
nffs_file_read(struct nffs_file *file, uint32_t len, void *out_data,
uint32_t *out_len)
{
uint32_t bytes_read;
int rc;
if (!nffs_misc_ready()) {
return FS_EUNINIT;
}
if (!(file->nf_access_flags & FS_ACCESS_READ)) {
return FS_EACCESS;
}
rc = nffs_inode_read(file->nf_inode_entry, file->nf_offset, len, out_data,
&bytes_read);
if (rc != 0) {
return rc;
}
file->nf_offset += bytes_read;
if (out_len != NULL) {
*out_len = bytes_read;
}
return 0;
}
/**
* Closes the specified file and invalidates the file handle. If the file has
* already been unlinked, and this is the last open handle to the file, this
* operation causes the file to be deleted.
*
* @param file The file handle to close.
*
* @return 0 on success; nonzero on failure.
*/
int
nffs_file_close(struct nffs_file *file)
{
int rc;
rc = nffs_inode_dec_refcnt(file->nf_inode_entry);
if (rc != 0) {
return rc;
}
rc = nffs_file_free(file);
if (rc != 0) {
return rc;
}
return 0;
}