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rockbox/firmware/common/file.c
Linus Nielsen Feltzing 5c8e82e097 You can't open() a directory as a file (at least not for writing) 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@4359 a1c6a512-1295-4272-9138-f99709370657
2004-03-10 19:47:59 +00:00

636 lines
15 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Björn Stenberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include "file.h"
#include "fat.h"
#include "dir.h"
#include "debug.h"
/*
These functions provide a roughly POSIX-compatible file IO API.
Since the fat32 driver only manages sectors, we maintain a one-sector
cache for each open file. This way we can provide byte access without
having to re-read the sector each time.
The penalty is the RAM used for the cache and slightly more complex code.
*/
#define MAX_OPEN_FILES 8
struct filedesc {
unsigned char cache[SECTOR_SIZE];
int cacheoffset;
int fileoffset;
int size;
int attr;
struct fat_file fatfile;
bool busy;
bool write;
bool dirty;
bool trunc;
};
static struct filedesc openfiles[MAX_OPEN_FILES];
static int flush_cache(int fd);
int creat(const char *pathname, mode_t mode)
{
(void)mode;
return open(pathname, O_WRONLY|O_CREAT|O_TRUNC);
}
int open(const char* pathname, int flags)
{
DIR* dir;
struct dirent* entry;
int fd;
char* name;
struct filedesc* file = NULL;
int rc;
LDEBUGF("open(\"%s\",%d)\n",pathname,flags);
if ( pathname[0] != '/' ) {
DEBUGF("'%s' is not an absolute path.\n",pathname);
DEBUGF("Only absolute pathnames supported at the moment\n");
errno = EINVAL;
return -1;
}
/* find a free file descriptor */
for ( fd=0; fd<MAX_OPEN_FILES; fd++ )
if ( !openfiles[fd].busy )
break;
if ( fd == MAX_OPEN_FILES ) {
DEBUGF("Too many files open\n");
errno = EMFILE;
return -2;
}
file = &openfiles[fd];
memset(file, 0, sizeof(struct filedesc));
if (flags & (O_RDWR | O_WRONLY)) {
file->write = true;
if (flags & O_TRUNC)
file->trunc = true;
}
file->busy = true;
/* locate filename */
name=strrchr(pathname+1,'/');
if ( name ) {
*name = 0;
dir = opendir((char*)pathname);
*name = '/';
name++;
}
else {
dir = opendir("/");
name = (char*)pathname+1;
}
if (!dir) {
DEBUGF("Failed opening dir\n");
errno = EIO;
file->busy = false;
return -4;
}
if(name[0] == 0) {
DEBUGF("Empty file name\n");
errno = EINVAL;
file->busy = false;
closedir(dir);
return -5;
}
/* scan dir for name */
while ((entry = readdir(dir))) {
if ( !strcasecmp(name, entry->d_name) ) {
fat_open(entry->startcluster,
&(file->fatfile),
&(dir->fatdir));
file->size = entry->size;
file->attr = entry->attribute;
break;
}
}
if ( !entry ) {
LDEBUGF("Didn't find file %s\n",name);
if ( file->write && (flags & O_CREAT) ) {
rc = fat_create_file(name,
&(file->fatfile),
&(dir->fatdir));
if (rc < 0) {
DEBUGF("Couldn't create %s in %s\n",name,pathname);
errno = EIO;
file->busy = false;
closedir(dir);
return rc * 10 - 6;
}
file->size = 0;
file->attr = 0;
}
else {
DEBUGF("Couldn't find %s in %s\n",name,pathname);
errno = ENOENT;
file->busy = false;
closedir(dir);
return -7;
}
} else {
if(file->write && (file->attr & FAT_ATTR_DIRECTORY)) {
errno = EISDIR;
file->busy = false;
closedir(dir);
return -8;
}
}
closedir(dir);
file->cacheoffset = -1;
file->fileoffset = 0;
if (file->write && (flags & O_APPEND)) {
rc = lseek(fd,0,SEEK_END);
if (rc < 0 )
return rc * 10 - 9;
}
return fd;
}
int close(int fd)
{
struct filedesc* file = &openfiles[fd];
int rc = 0;
LDEBUGF("close(%d)\n", fd);
if (fd < 0 || fd > MAX_OPEN_FILES-1) {
errno = EINVAL;
return -1;
}
if (!file->busy) {
errno = EBADF;
return -2;
}
if (file->write) {
rc = fsync(fd);
if (rc < 0)
return rc * 10 - 3;
}
file->busy = false;
return 0;
}
int fsync(int fd)
{
struct filedesc* file = &openfiles[fd];
int rc = 0;
LDEBUGF("fsync(%d)\n", fd);
if (fd < 0 || fd > MAX_OPEN_FILES-1) {
errno = EINVAL;
return -1;
}
if (!file->busy) {
errno = EBADF;
return -2;
}
if (file->write) {
/* flush sector cache */
if ( file->dirty ) {
rc = flush_cache(fd);
if (rc < 0)
return rc * 10 - 3;
}
/* truncate? */
if (file->trunc) {
rc = ftruncate(fd, file->fileoffset);
if (rc < 0)
return rc * 10 - 4;
}
/* tie up all loose ends */
rc = fat_closewrite(&(file->fatfile), file->size, file->attr);
if (rc < 0)
return rc * 10 - 5;
}
return 0;
}
int remove(const char* name)
{
int rc;
struct filedesc* file;
int fd = open(name, O_WRONLY);
if ( fd < 0 )
return fd * 10 - 1;
file = &openfiles[fd];
rc = fat_truncate(&(file->fatfile));
if ( rc < 0 ) {
DEBUGF("Failed truncating file: %d\n", rc);
errno = EIO;
return rc * 10 - 2;
}
rc = fat_remove(&(file->fatfile));
if ( rc < 0 ) {
DEBUGF("Failed removing file: %d\n", rc);
errno = EIO;
return rc * 10 - 3;
}
file->size = 0;
rc = close(fd);
if (rc<0)
return rc * 10 - 4;
return 0;
}
int rename(const char* path, const char* newpath)
{
int rc, fd;
char* nameptr;
struct filedesc* file;
/* verify new path does not already exist */
fd = open(newpath, O_RDONLY);
if ( fd >= 0 ) {
close(fd);
errno = EBUSY;
return -1;
}
close(fd);
fd = open(path, O_RDONLY);
if ( fd < 0 ) {
errno = EIO;
return fd * 10 - 2;
}
/* strip path */
nameptr = strrchr(newpath,'/');
if (nameptr)
nameptr++;
else
nameptr = (char*)newpath;
file = &openfiles[fd];
rc = fat_rename(&file->fatfile, nameptr, file->size, file->attr);
if ( rc < 0 ) {
DEBUGF("Failed renaming file: %d\n", rc);
errno = EIO;
return rc * 10 - 3;
}
rc = close(fd);
if (rc<0) {
errno = EIO;
return rc * 10 - 4;
}
return 0;
}
int ftruncate(int fd, off_t size)
{
int rc, sector;
struct filedesc* file = &openfiles[fd];
sector = size / SECTOR_SIZE;
if (size % SECTOR_SIZE)
sector++;
rc = fat_seek(&(file->fatfile), sector);
if (rc < 0) {
errno = EIO;
return rc * 10 - 1;
}
rc = fat_truncate(&(file->fatfile));
if (rc < 0) {
errno = EIO;
return rc * 10 - 2;
}
file->size = size;
return 0;
}
static int flush_cache(int fd)
{
int rc;
struct filedesc* file = &openfiles[fd];
int sector = file->fileoffset / SECTOR_SIZE;
DEBUGF("Flushing dirty sector cache\n");
/* make sure we are on correct sector */
rc = fat_seek(&(file->fatfile), sector);
if ( rc < 0 )
return rc * 10 - 3;
rc = fat_readwrite(&(file->fatfile), 1,
file->cache, true );
if ( rc < 0 ) {
if(file->fatfile.eof)
errno = ENOSPC;
return rc * 10 - 2;
}
file->dirty = false;
return 0;
}
static int readwrite(int fd, void* buf, int count, bool write)
{
int sectors;
int nread=0;
struct filedesc* file = &openfiles[fd];
int rc;
if ( !file->busy ) {
errno = EBADF;
return -1;
}
LDEBUGF( "readwrite(%d,%x,%d,%s)\n",
fd,buf,count,write?"write":"read");
/* attempt to read past EOF? */
if (!write && count > file->size - file->fileoffset)
count = file->size - file->fileoffset;
/* any head bytes? */
if ( file->cacheoffset != -1 ) {
int headbytes;
int offs = file->cacheoffset;
if ( count <= SECTOR_SIZE - file->cacheoffset ) {
headbytes = count;
file->cacheoffset += count;
if ( file->cacheoffset >= SECTOR_SIZE )
file->cacheoffset = -1;
}
else {
headbytes = SECTOR_SIZE - file->cacheoffset;
file->cacheoffset = -1;
}
if (write) {
memcpy( file->cache + offs, buf, headbytes );
if (offs+headbytes == SECTOR_SIZE) {
int rc = flush_cache(fd);
if ( rc < 0 ) {
errno = EIO;
return rc * 10 - 2;
}
file->cacheoffset = -1;
}
else
file->dirty = true;
}
else {
memcpy( buf, file->cache + offs, headbytes );
}
nread = headbytes;
count -= headbytes;
}
/* if buffer has been modified, write it back to disk */
if (nread && file->dirty) {
rc = flush_cache(fd);
if (rc < 0)
return rc * 10 - 3;
}
/* read/write whole sectors right into/from the supplied buffer */
sectors = count / SECTOR_SIZE;
if ( sectors ) {
int rc = fat_readwrite(&(file->fatfile), sectors, buf+nread, write );
if ( rc < 0 ) {
DEBUGF("Failed read/writing %d sectors\n",sectors);
errno = EIO;
if(write && file->fatfile.eof) {
DEBUGF("No space left on device\n");
errno = ENOSPC;
} else {
file->fileoffset += nread;
}
file->cacheoffset = -1;
return nread ? nread : rc * 10 - 4;
}
else {
if ( rc > 0 ) {
nread += rc * SECTOR_SIZE;
count -= sectors * SECTOR_SIZE;
/* if eof, skip tail bytes */
if ( rc < sectors )
count = 0;
}
else {
/* eof */
count=0;
}
file->cacheoffset = -1;
}
}
/* any tail bytes? */
if ( count ) {
if (write) {
if ( file->fileoffset + nread < file->size ) {
/* sector is only partially filled. copy-back from disk */
int rc;
LDEBUGF("Copy-back tail cache\n");
rc = fat_readwrite(&(file->fatfile), 1, file->cache, false );
if ( rc < 0 ) {
DEBUGF("Failed writing\n");
errno = EIO;
file->fileoffset += nread;
file->cacheoffset = -1;
return nread ? nread : rc * 10 - 5;
}
/* seek back one sector to put file position right */
rc = fat_seek(&(file->fatfile),
(file->fileoffset + nread) /
SECTOR_SIZE);
if ( rc < 0 ) {
DEBUGF("fat_seek() failed\n");
errno = EIO;
file->fileoffset += nread;
file->cacheoffset = -1;
return nread ? nread : rc * 10 - 6;
}
}
memcpy( file->cache, buf + nread, count );
file->dirty = true;
}
else {
rc = fat_readwrite(&(file->fatfile), 1, &(file->cache),false);
if (rc < 1 ) {
DEBUGF("Failed caching sector\n");
errno = EIO;
file->fileoffset += nread;
file->cacheoffset = -1;
return nread ? nread : rc * 10 - 7;
}
memcpy( buf + nread, file->cache, count );
}
nread += count;
file->cacheoffset = count;
}
file->fileoffset += nread;
LDEBUGF("fileoffset: %d\n", file->fileoffset);
/* adjust file size to length written */
if ( write && file->fileoffset > file->size )
file->size = file->fileoffset;
return nread;
}
ssize_t write(int fd, const void* buf, size_t count)
{
if (!openfiles[fd].write) {
errno = EACCES;
return -1;
}
return readwrite(fd, (void *)buf, count, true);
}
ssize_t read(int fd, void* buf, size_t count)
{
return readwrite(fd, buf, count, false);
}
off_t lseek(int fd, off_t offset, int whence)
{
int pos;
int newsector;
int oldsector;
int sectoroffset;
int rc;
struct filedesc* file = &openfiles[fd];
LDEBUGF("lseek(%d,%d,%d)\n",fd,offset,whence);
if ( !file->busy ) {
errno = EBADF;
return -1;
}
switch ( whence ) {
case SEEK_SET:
pos = offset;
break;
case SEEK_CUR:
pos = file->fileoffset + offset;
break;
case SEEK_END:
pos = file->size + offset;
break;
default:
errno = EINVAL;
return -2;
}
if ((pos < 0) || (pos > file->size)) {
errno = EINVAL;
return -3;
}
/* new sector? */
newsector = pos / SECTOR_SIZE;
oldsector = file->fileoffset / SECTOR_SIZE;
sectoroffset = pos % SECTOR_SIZE;
if ( (newsector != oldsector) ||
((file->cacheoffset==-1) && sectoroffset) ) {
if ( newsector != oldsector ) {
if (file->dirty) {
rc = flush_cache(fd);
if (rc < 0)
return rc * 10 - 5;
}
rc = fat_seek(&(file->fatfile), newsector);
if ( rc < 0 ) {
errno = EIO;
return rc * 10 - 4;
}
}
if ( sectoroffset ) {
rc = fat_readwrite(&(file->fatfile), 1,
&(file->cache),false);
if ( rc < 0 ) {
errno = EIO;
return rc * 10 - 6;
}
file->cacheoffset = sectoroffset;
}
else
file->cacheoffset = -1;
}
else
if ( file->cacheoffset != -1 )
file->cacheoffset = sectoroffset;
file->fileoffset = pos;
return pos;
}
int filesize(int fd)
{
struct filedesc* file = &openfiles[fd];
if ( !file->busy ) {
errno = EBADF;
return -1;
}
return file->size;
}
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