Nyaaori/rockbox
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
rockbox/firmware/common/file.c
William Wilgus 5ef28cccf9 Allow mounting of any directory as the root directory. 
Provide definitions for the macros:
* RB_ROOT_VOL_HIDDEN(v) to exclude certain items from the root.
* RB_ROOT_CONTENTS to return a string with the name of the
directory to mount in the root.

Defaults are in export/rbpaths.h

It's a bit much for those that don't need the full functionality.
Some conditional define can cut it back a lot to cut out things only
needed if alternate root mounts are required. I'm just not bothering
yet. The basic concept would be applied to all targets to keep file
code from forking too much.

Change-Id: I90b5c0a1c949283d3102c16734b0b6ac73901a30
2020-08-20 23:08:57 +00:00

1232 lines
34 KiB
C
Raw Blame History

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Björn Stenberg
* Copyright (C) 2014 by Michael Sevakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#define RB_FILESYSTEM_OS
#include "config.h"
#include "system.h"
#include <string.h>
#include <errno.h>
#include "debug.h"
#include "file.h"
#include "fileobj_mgr.h"
#include "disk_cache.h"
#include "rb_namespace.h"
#include "string-extra.h"
/**
* These functions provide a roughly POSIX-compatible file I/O API.
*/
/* structure used for open file descriptors */
static struct filestr_desc
{
struct filestr_base stream; /* basic stream info (first!) */
file_size_t offset; /* current offset for stream */
file_size_t *sizep; /* shortcut to file size in fileobj */
} open_streams[MAX_OPEN_FILES];
/* check and return a struct filestr_desc* from a file descriptor number */
static struct filestr_desc * get_filestr(int fildes)
{
struct filestr_desc *file = &open_streams[fildes];
if ((unsigned int)fildes >= MAX_OPEN_FILES)
file = NULL;
else if (file->stream.flags & FDO_BUSY)
return file;
DEBUGF("fildes %d: bad file number\n", fildes);
errno = (file && (file->stream.flags & FD_NONEXIST)) ? ENXIO : EBADF;
return NULL;
}
#define GET_FILESTR(type, fildes) \
({ \
file_internal_lock_##type(); \
struct filestr_desc * _file = get_filestr(fildes); \
if (_file) \
FILESTR_LOCK(type, &_file->stream); \
else \
file_internal_unlock_##type(); \
_file; \
})
/* release the lock on the filestr_desc* */
#define RELEASE_FILESTR(type, file) \
({ \
FILESTR_UNLOCK(type, &(file)->stream); \
file_internal_unlock_##type(); \
})
/* find a free file descriptor */
static int alloc_filestr(struct filestr_desc **filep)
{
for (int fildes = 0; fildes < MAX_OPEN_FILES; fildes++)
{
struct filestr_desc *file = &open_streams[fildes];
if (!file->stream.flags)
{
*filep = file;
return fildes;
}
}
DEBUGF("Too many files open\n");
return -1;
}
/* return the file size in sectors */
static inline unsigned long filesize_sectors(file_size_t size)
{
/* overflow proof whereas "(x + y - 1) / y" is not */
unsigned long numsectors = size / SECTOR_SIZE;
if (size % SECTOR_SIZE)
numsectors++;
return numsectors;
}
/* flush a dirty cache buffer */
static int flush_cache(struct filestr_desc *file)
{
int rc;
struct filestr_cache *cachep = file->stream.cachep;
DEBUGF("Flushing dirty sector cache (%lu)\n", cachep->sector);
if (fat_query_sectornum(&file->stream.fatstr) != cachep->sector)
{
/* get on the correct sector */
rc = fat_seek(&file->stream.fatstr, cachep->sector);
if (rc < 0)
FILE_ERROR(EIO, rc * 10 - 1);
}
rc = fat_readwrite(&file->stream.fatstr, 1, cachep->buffer, true);
if (rc < 0)
{
if (rc == FAT_RC_ENOSPC)
FILE_ERROR(ENOSPC, RC);
else
FILE_ERROR(EIO, rc * 10 - 2);
}
cachep->flags = 0;
return 1;
file_error:
DEBUGF("Failed flushing cache: %d\n", rc);
return rc;
}
static void discard_cache(struct filestr_desc *file)
{
struct filestr_cache *const cachep = file->stream.cachep;
cachep->flags = 0;
}
/* set the file pointer */
static off_t lseek_internal(struct filestr_desc *file, off_t offset,
int whence)
{
off_t rc;
file_size_t pos;
file_size_t size = MIN(*file->sizep, FILE_SIZE_MAX);
switch (whence)
{
case SEEK_SET:
if (offset < 0 || (file_size_t)offset > size)
FILE_ERROR(EINVAL, -1);
pos = offset;
break;
case SEEK_CUR:
if ((offset < 0 && (file_size_t)-offset > file->offset) ||
(offset > 0 && (file_size_t)offset > size - file->offset))
FILE_ERROR(EINVAL, -1);
pos = file->offset + offset;
break;
case SEEK_END:
if (offset > 0 || (file_size_t)-offset > size)
FILE_ERROR(EINVAL, -1);
pos = size + offset;
break;
default:
FILE_ERROR(EINVAL, -1);
}
file->offset = pos;
return pos;
file_error:
return rc;
}
/* Handle syncing all file's streams to the truncation */
static void handle_truncate(struct filestr_desc * const file, file_size_t size)
{
unsigned long filesectors = filesize_sectors(size);
struct filestr_base *s = NULL;
while ((s = fileobj_get_next_stream(&file->stream, s)))
{
/* caches with data beyond new extents are invalid */
unsigned long sector = s->cachep->sector;
if (sector != INVALID_SECNUM && sector >= filesectors)
filestr_discard_cache(s);
/* files outside bounds must be rewound */
if (fat_query_sectornum(&s->fatstr) > filesectors)
fat_seek_to_stream(&s->fatstr, &file->stream.fatstr);
/* clip file offset too if needed */
struct filestr_desc *f = (struct filestr_desc *)s;
if (f->offset > size)
f->offset = size;
}
}
/* truncate the file to the specified length */
static int ftruncate_internal(struct filestr_desc *file, file_size_t size,
bool write_now)
{
int rc = 0, rc2 = 1;
file_size_t cursize = *file->sizep;
file_size_t truncsize = MIN(size, cursize);
if (write_now)
{
unsigned long sector = filesize_sectors(truncsize);
struct filestr_cache *const cachep = file->stream.cachep;
if (cachep->flags == (FSC_NEW|FSC_DIRTY) &&
cachep->sector + 1 == sector)
{
/* sector created but may have never been added to the cluster
chain; flush it now or the subsequent may fail */
rc2 = flush_cache(file);
if (rc2 == FAT_RC_ENOSPC)
{
/* no space left on device; further truncation needed */
discard_cache(file);
truncsize = ALIGN_DOWN(truncsize - 1, SECTOR_SIZE);
sector--;
rc = rc2;
}
else if (rc2 < 0)
FILE_ERROR(ERRNO, rc2 * 10 - 1);
}
rc2 = fat_seek(&file->stream.fatstr, sector);
if (rc2 < 0)
FILE_ERROR(EIO, rc2 * 10 - 2);
rc2 = fat_truncate(&file->stream.fatstr);
if (rc2 < 0)
FILE_ERROR(EIO, rc2 * 10 - 3);
/* never needs to be done this way again since any data beyond the
cached size is now gone */
fileobj_change_flags(&file->stream, 0, FO_TRUNC);
}
/* else just change the cached file size */
if (truncsize < cursize)
{
*file->sizep = truncsize;
handle_truncate(file, truncsize);
}
/* if truncation was partially successful, it effectively destroyed
everything after the truncation point; still, indicate failure
after adjusting size */
if (rc2 == 0)
FILE_ERROR(EIO, -4);
else if (rc2 < 0)
FILE_ERROR(ERRNO, rc2);
file_error:
return rc;
}
/* flush back all outstanding writes to the file */
static int fsync_internal(struct filestr_desc *file)
{
/* call only when holding WRITER lock (updates directory entries) */
int rc = 0;
file_size_t size = *file->sizep;
unsigned int foflags = fileobj_get_flags(&file->stream);
/* flush sector cache? */
struct filestr_cache *const cachep = file->stream.cachep;
if (cachep->flags & FSC_DIRTY)
{
int rc2 = flush_cache(file);
if (rc2 == FAT_RC_ENOSPC && (cachep->flags & FSC_NEW))
{
/* no space left on device so this must be dropped */
discard_cache(file);
size = ALIGN_DOWN(size - 1, SECTOR_SIZE);
foflags |= FO_TRUNC;
rc = rc2;
}
else if (rc2 < 0)
FILE_ERROR(ERRNO, rc2 * 10 - 1);
}
/* truncate? */
if (foflags & FO_TRUNC)
{
int rc2 = ftruncate_internal(file, size, rc == 0);
if (rc2 < 0)
FILE_ERROR(ERRNO, rc2 * 10 - 2);
}
file_error:;
/* tie up all loose ends (try to close the file even if failing) */
int rc2 = fat_closewrite(&file->stream.fatstr, size,
get_dir_fatent_dircache());
if (rc2 >= 0)
fileop_onsync_internal(&file->stream); /* dir_fatent is implicit arg */
if (rc2 < 0 && rc >= 0)
{
errno = EIO;
rc = rc2 * 10 - 3;
}
return rc;
}
/* finish with the file and free resources */
static int close_internal(struct filestr_desc *file)
{
/* call only when holding WRITER lock (updates directory entries) */
int rc;
if ((file->stream.flags & (FD_WRITE|FD_NONEXIST)) == FD_WRITE)
{
rc = fsync_internal(file);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 1);
}
rc = 0;
file_error:;
int rc2 = close_stream_internal(&file->stream);
if (rc2 < 0 && rc >= 0)
rc = rc2 * 10 - 2;
return rc;
}
/* actually do the open gruntwork */
static int open_internal_inner2(const char *path,
struct filestr_desc *file,
unsigned int callflags,
int oflag)
{
int rc;
struct path_component_info compinfo;
if (oflag & O_CREAT)
callflags |= FF_PARENTINFO;
rc = open_stream_internal(path, callflags, &file->stream, &compinfo);
if (rc < 0)
{
DEBUGF("Open failed: %d\n", rc);
FILE_ERROR_RETURN(ERRNO, rc * 10 - 1);
}
bool created = false;
if (rc > 0)
{
if (oflag & O_EXCL)
{
DEBUGF("File exists\n");
FILE_ERROR(EEXIST, -2);
}
if (compinfo.attr & ATTR_DIRECTORY)
{
if ((callflags & FD_WRITE) || !(callflags & FF_ANYTYPE))
{
DEBUGF("File is a directory\n");
FILE_ERROR(EISDIR, -3);
}
compinfo.filesize = MAX_DIRECTORY_SIZE; /* allow file ops */
}
}
else if (oflag & O_CREAT)
{
if (compinfo.attr & ATTR_DIRECTORY)
{
DEBUGF("File is a directory\n");
FILE_ERROR(EISDIR, -5);
}
/* not found; try to create it */
callflags &= ~FO_TRUNC;
rc = create_stream_internal(&compinfo.parentinfo, compinfo.name,
compinfo.length, ATTR_NEW_FILE, callflags,
&file->stream);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 6);
created = true;
}
else
{
DEBUGF("File not found\n");
FILE_ERROR(ENOENT, -7);
}
fat_rewind(&file->stream.fatstr);
file->sizep = fileobj_get_sizep(&file->stream);
file->offset = 0;
if (!created)
{
/* size from storage applies to first stream only otherwise it's
already up to date */
const bool first = fileobj_get_flags(&file->stream) & FO_SINGLE;
if (first)
*file->sizep = compinfo.filesize;
if (callflags & FO_TRUNC)
{
/* if the file is kind of "big" then free some space now */
rc = ftruncate_internal(file, 0, *file->sizep >= O_TRUNC_THRESH);
if (rc < 0)
{
DEBUGF("O_TRUNC failed: %d\n", rc);
FILE_ERROR(ERRNO, rc * 10 - 4);
}
}
}
rc = 0;
file_error:
if (rc < 0)
close_stream_internal(&file->stream);
return rc;
}
/* allocate a file descriptor, if needed, assemble stream flags and open
a new stream */
static int open_internal_inner1(const char *path, int oflag,
unsigned int callflags)
{
DEBUGF("%s(path=\"%s\",oflag=%X,callflags=%X)\n", __func__,
path, oflag, callflags);
int rc;
struct filestr_desc *file;
int fildes = alloc_filestr(&file);
if (fildes < 0)
FILE_ERROR(EMFILE, -1);
callflags &= ~FDO_MASK;
if (oflag & O_ACCMODE)
{
callflags |= FD_WRITE;
if ((oflag & O_ACCMODE) == O_WRONLY)
callflags |= FD_WRONLY;
if (oflag & O_APPEND)
callflags |= FD_APPEND;
if (oflag & O_TRUNC)
callflags |= FO_TRUNC;
}
else if (oflag & O_TRUNC)
{
/* O_TRUNC requires write mode */
DEBUGF("No write mode but have O_TRUNC\n");
FILE_ERROR(EINVAL, -2);
}
/* O_CREAT and O_APPEND are fine without write mode
* for the former, an empty file is created but no data may be written
* for the latter, no append will be allowed anyway */
if (!(oflag & O_CREAT))
oflag &= ~O_EXCL; /* result is undefined: we choose "ignore" */
rc = open_internal_inner2(path, file, callflags, oflag);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
return fildes;
file_error:
return rc;
}
static int open_internal_locked(const char *path, int oflag,
unsigned int callflags)
{
file_internal_lock_WRITER();
int rc = open_internal_inner1(path, oflag, callflags);
file_internal_unlock_WRITER();
return rc;
}
/* fill a cache buffer with a new sector */
static int readwrite_fill_cache(struct filestr_desc *file, unsigned long sector,
unsigned long filesectors, bool write)
{
/* sector != cachep->sector should have been checked by now */
int rc;
struct filestr_cache *cachep = filestr_get_cache(&file->stream);
if (cachep->flags & FSC_DIRTY)
{
rc = flush_cache(file);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 1);
}
if (fat_query_sectornum(&file->stream.fatstr) != sector)
{
/* get on the correct sector */
rc = fat_seek(&file->stream.fatstr, sector);
if (rc < 0)
FILE_ERROR(EIO, rc * 10 - 2);
}
if (!write || sector < filesectors)
{
/* only reading or this sector would have been flushed if the cache
was previously needed for a different sector */
rc = fat_readwrite(&file->stream.fatstr, 1, cachep->buffer, false);
if (rc < 0)
FILE_ERROR(rc == FAT_RC_ENOSPC ? ENOSPC : EIO, rc * 10 - 3);
}
else
{
/* create a fresh, shiny, new sector with that new sector smell */
cachep->flags = FSC_NEW;
}
cachep->sector = sector;
return 1;
file_error:
DEBUGF("Failed caching sector: %d\n", rc);
return rc;
}
/* read or write to part or all of the cache buffer */
static inline void readwrite_cache(struct filestr_cache *cachep, void *buf,
unsigned long secoffset, size_t nbyte,
bool write)
{
void *dst, *cbufp = cachep->buffer + secoffset;
if (write)
{
dst = cbufp;
cachep->flags |= FSC_DIRTY;
}
else
{
dst = buf;
buf = cbufp;
}
memcpy(dst, buf, nbyte);
}
/* read or write a partial sector using the file's cache */
static inline ssize_t readwrite_partial(struct filestr_desc *file,
struct filestr_cache *cachep,
unsigned long sector,
unsigned long secoffset,
void *buf,
size_t nbyte,
unsigned long filesectors,
unsigned int flags)
{
if (sector != cachep->sector)
{
/* wrong sector in buffer */
int rc = readwrite_fill_cache(file, sector, filesectors, flags);
if (rc <= 0)
return rc;
}
readwrite_cache(cachep, buf, secoffset, nbyte, flags);
return nbyte;
}
/* read from or write to the file; back end to read() and write() */
static ssize_t readwrite(struct filestr_desc *file, void *buf, size_t nbyte,
bool write)
{
DEBUGF("readwrite(%p,%lx,%lu,%s)\n",
file, (long)buf, (unsigned long)nbyte, write ? "write" : "read");
const file_size_t size = *file->sizep;
file_size_t filerem;
if (write)
{
/* if opened in append mode, move pointer to end */
if (file->stream.flags & FD_APPEND)
file->offset = MIN(size, FILE_SIZE_MAX);
filerem = FILE_SIZE_MAX - file->offset;
}
else
{
/* limit to maximum possible offset (EOF or FILE_SIZE_MAX) */
filerem = MIN(size, FILE_SIZE_MAX) - file->offset;
}
if (nbyte > filerem)
{
nbyte = filerem;
if (nbyte > 0)
{}
else if (write)
FILE_ERROR_RETURN(EFBIG, -1); /* would get too large */
else if (file->offset >= FILE_SIZE_MAX)
FILE_ERROR_RETURN(EOVERFLOW, -2); /* can't read here */
}
if (nbyte == 0)
return 0;
int rc = 0;
struct filestr_cache * const cachep = file->stream.cachep;
void * const bufstart = buf;
const unsigned long filesectors = filesize_sectors(size);
unsigned long sector = file->offset / SECTOR_SIZE;
unsigned long sectoroffs = file->offset % SECTOR_SIZE;
/* any head bytes? */
if (sectoroffs)
{
size_t headbytes = MIN(nbyte, SECTOR_SIZE - sectoroffs);
rc = readwrite_partial(file, cachep, sector, sectoroffs, buf, headbytes,
filesectors, write);
if (rc <= 0)
{
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
nbyte = 0; /* eof, skip the rest */
}
else
{
buf += rc;
nbyte -= rc;
sector++; /* if nbyte goes to 0, the rest is skipped anyway */
}
}
/* read/write whole sectors right into/from the supplied buffer */
unsigned long sectorcount = nbyte / SECTOR_SIZE;
while (sectorcount)
{
unsigned long runlen = sectorcount;
/* if a cached sector is inside the transfer range, split the transfer
into two parts and use the cache for that sector to keep it coherent
without writeback */
if (UNLIKELY(cachep->sector >= sector &&
cachep->sector < sector + sectorcount))
{
runlen = cachep->sector - sector;
}
if (runlen)
{
if (fat_query_sectornum(&file->stream.fatstr) != sector)
{
/* get on the correct sector */
rc = 0;
/* If the dirty bit isn't set, we're somehow beyond the file
size and you can't explain _that_ */
if (sector >= filesectors && cachep->flags == (FSC_NEW|FSC_DIRTY))
{
rc = flush_cache(file);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 4);
if (cachep->sector + 1 == sector)
rc = 1; /* if now ok, don't seek */
}
if (rc == 0)
{
rc = fat_seek(&file->stream.fatstr, sector);
if (rc < 0)
FILE_ERROR(EIO, rc * 10 - 5);
}
}
rc = fat_readwrite(&file->stream.fatstr, runlen, buf, write);
if (rc < 0)
{
DEBUGF("I/O error %sing %ld sectors\n",
write ? "writ" : "read", runlen);
FILE_ERROR(rc == FAT_RC_ENOSPC ? ENOSPC : EIO,
rc * 10 - 6);
}
else
{
buf += rc * SECTOR_SIZE;
nbyte -= rc * SECTOR_SIZE;
sector += rc;
sectorcount -= rc;
/* if eof, skip tail bytes */
if ((unsigned long)rc < runlen)
nbyte = 0;
if (!nbyte)
break;
}
}
if (UNLIKELY(sectorcount && sector == cachep->sector))
{
/* do this one sector with the cache */
readwrite_cache(cachep, buf, 0, SECTOR_SIZE, write);
buf += SECTOR_SIZE;
nbyte -= SECTOR_SIZE;
sector++;
sectorcount--;
}
}
/* any tail bytes? */
if (nbyte)
{
/* tail bytes always start at sector offset 0 */
rc = readwrite_partial(file, cachep, sector, 0, buf, nbyte,
filesectors, write);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 7);
buf += rc;
}
file_error:;
#ifdef DEBUG
if (errno == ENOSPC)
DEBUGF("No space left on device\n");
#endif
size_t done = buf - bufstart;
if (done)
{
/* error or not, update the file offset and size if anything was
transferred */
file->offset += done;
DEBUGF("file offset: %ld\n", file->offset);
/* adjust file size to length written */
if (write && file->offset > size)
*file->sizep = file->offset;
if (rc > 0)
return done;
}
return rc;
}
/** Internal interface **/
/* open a file without codepage conversion during the directory search;
required to avoid any reentrancy when opening codepages and when scanning
directories internally, which could infinitely recurse and would corrupt
the static data */
int open_noiso_internal(const char *path, int oflag)
{
return open_internal_locked(path, oflag, FF_ANYTYPE | FF_NOISO);
}
void force_close_writer_internal(struct filestr_base *stream)
{
/* only we do writers so we know this is our guy */
close_internal((struct filestr_desc *)stream);
}
/** POSIX **/
/* open a file */
int open(const char *path, int oflag)
{
DEBUGF("open(path=\"%s\",oflag=%X)\n", path, (unsigned)oflag);
return open_internal_locked(path, oflag, FF_ANYTYPE);
}
/* create a new file or rewrite an existing one */
int creat(const char *path)
{
DEBUGF("creat(path=\"%s\")\n", path);
return open_internal_locked(path, O_WRONLY|O_CREAT|O_TRUNC, FF_ANYTYPE);
}
/* close a file descriptor */
int close(int fildes)
{
DEBUGF("close(fd=%d)\n", fildes);
int rc;
file_internal_lock_WRITER();
/* needs to work even if marked "nonexistant" */
struct filestr_desc *file = &open_streams[fildes];
if ((unsigned int)fildes >= MAX_OPEN_FILES || !file->stream.flags)
{
DEBUGF("filedes %d not open\n", fildes);
FILE_ERROR(EBADF, -2);
}
rc = close_internal(file);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
file_error:
file_internal_unlock_WRITER();
return rc;
}
/* truncate a file to a specified length */
int ftruncate(int fildes, off_t length)
{
DEBUGF("ftruncate(fd=%d,len=%ld)\n", fildes, (long)length);
struct filestr_desc * const file = GET_FILESTR(READER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
int rc;
if (!(file->stream.flags & FD_WRITE))
{
DEBUGF("Descriptor is read-only mode\n");
FILE_ERROR(EBADF, -2);
}
if (length < 0)
{
DEBUGF("Length %ld is invalid\n", (long)length);
FILE_ERROR(EINVAL, -3);
}
rc = ftruncate_internal(file, length, true);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 4);
file_error:
RELEASE_FILESTR(READER, file);
return rc;
}
/* synchronize changes to a file */
int fsync(int fildes)
{
DEBUGF("fsync(fd=%d)\n", fildes);
struct filestr_desc * const file = GET_FILESTR(WRITER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
int rc;
if (!(file->stream.flags & FD_WRITE))
{
DEBUGF("Descriptor is read-only mode\n");
FILE_ERROR(EINVAL, -2);
}
rc = fsync_internal(file);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
file_error:
RELEASE_FILESTR(WRITER, file);
return rc;
}
/* move the read/write file offset */
off_t lseek(int fildes, off_t offset, int whence)
{
DEBUGF("lseek(fd=%d,ofs=%ld,wh=%d)\n", fildes, (long)offset, whence);
struct filestr_desc * const file = GET_FILESTR(READER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
off_t rc = lseek_internal(file, offset, whence);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 2);
file_error:
RELEASE_FILESTR(READER, file);
return rc;
}
/* read from a file */
ssize_t read(int fildes, void *buf, size_t nbyte)
{
struct filestr_desc * const file = GET_FILESTR(READER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
ssize_t rc;
if (file->stream.flags & FD_WRONLY)
{
DEBUGF("read(fd=%d,buf=%p,nb=%lu) - "
"descriptor is write-only mode\n",
fildes, buf, (unsigned long)nbyte);
FILE_ERROR(EBADF, -2);
}
rc = readwrite(file, buf, nbyte, false);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
file_error:
RELEASE_FILESTR(READER, file);
return rc;
}
/* write on a file */
ssize_t write(int fildes, const void *buf, size_t nbyte)
{
struct filestr_desc * const file = GET_FILESTR(READER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
ssize_t rc;
if (!(file->stream.flags & FD_WRITE))
{
DEBUGF("write(fd=%d,buf=%p,nb=%lu) - "
"descriptor is read-only mode\n",
fildes, buf, (unsigned long)nbyte);
FILE_ERROR(EBADF, -2);
}
rc = readwrite(file, (void *)buf, nbyte, true);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 3);
file_error:
RELEASE_FILESTR(READER, file);
return rc;
}
/* remove a file */
int remove(const char *path)
{
DEBUGF("remove(path=\"%s\")\n", path);
file_internal_lock_WRITER();
int rc = remove_stream_internal(path, NULL, FF_FILE);
file_internal_unlock_WRITER();
return rc;
}
/* rename a file */
int rename(const char *old, const char *new)
{
DEBUGF("rename(old=\"%s\",new=\"%s\")\n", old, new);
int rc, open1rc = -1, open2rc = -1;
struct filestr_base oldstr, newstr;
struct path_component_info oldinfo, newinfo;
file_internal_lock_WRITER();
/* open 'old'; it must exist */
open1rc = open_stream_internal(old, FF_ANYTYPE | FF_PARENTINFO, &oldstr,
&oldinfo);
if (open1rc <= 0)
{
DEBUGF("Failed opening old: %d\n", open1rc);
if (open1rc == 0)
FILE_ERROR(ENOENT, -1);
else
FILE_ERROR(ERRNO, open1rc * 10 - 1);
}
/* if 'old' is a directory then 'new' is also required to be one if 'new'
is to be overwritten */
const bool are_dirs = oldinfo.attr & ATTR_DIRECTORY;
/* open new (may or may not exist) */
unsigned int callflags = FF_FILE;
if (are_dirs)
{
/* if 'old' is found while parsing the new directory components then
'new' contains path prefix that names 'old'; if new and old are in
the same directory, this tests positive but that is checked later */
callflags = FF_DIR | FF_CHECKPREFIX;
newinfo.prefixp = oldstr.infop;
}
open2rc = open_stream_internal(new, callflags | FF_PARENTINFO, &newstr,
&newinfo);
if (open2rc < 0)
{
DEBUGF("Failed opening new file: %d\n", open2rc);
FILE_ERROR(ERRNO, open2rc * 10 - 2);
}
#ifdef HAVE_MULTIVOLUME
if (oldinfo.parentinfo.volume != newinfo.parentinfo.volume)
{
DEBUGF("Cross-device link\n");
FILE_ERROR(EXDEV, -3);
}
#endif /* HAVE_MULTIVOLUME */
/* if the parent is changing then this is a move, not a simple rename */
const bool is_move = !fat_file_is_same(&oldinfo.parentinfo.fatfile,
&newinfo.parentinfo.fatfile);
/* prefix found and moving? */
if (is_move && (newinfo.attr & ATTR_PREFIX))
{
DEBUGF("New contains prefix that names old\n");
FILE_ERROR(EINVAL, -4);
}
const char * const oldname = strmemdupa(oldinfo.name, oldinfo.length);
const char * const newname = strmemdupa(newinfo.name, newinfo.length);
bool is_overwrite = false;
if (open2rc > 0)
{
/* new name exists in parent; check if 'old' is overwriting 'new';
if it's the very same file, then it's just a rename */
is_overwrite = oldstr.bindp != newstr.bindp;
if (is_overwrite)
{
if (are_dirs)
{
/* the directory to be overwritten must be empty */
rc = test_dir_empty_internal(&newstr);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 5);
}
}
else if (!strcmp(newname, oldname)) /* case-only is ok */
{
DEBUGF("No name change (success)\n");
rc = 0;
FILE_ERROR(ERRNO, RC);
}
}
else if (!are_dirs && (newinfo.attr & ATTR_DIRECTORY))
{
/* even if new doesn't exist, canonical path type must match
(ie. a directory path such as "/foo/bar/" when old names a file) */
DEBUGF("New path is a directory\n");
FILE_ERROR(EISDIR, -6);
}
/* first, create the new entry so that there's never a time that the
victim's data has no reference in the directory tree, that is, until
everything else first succeeds */
struct file_base_info old_fileinfo = *oldstr.infop;
rc = fat_rename(&newinfo.parentinfo.fatfile, &oldstr.infop->fatfile,
newname);
if (rc < 0)
{
DEBUGF("I/O error renaming file: %d\n", rc);
FILE_ERROR(rc == FAT_RC_ENOSPC ? ENOSPC : EIO, rc * 10 - 7);
}
if (is_overwrite)
{
/* 'new' would have been assigned its own directory entry and
succeeded so at this point it is treated like a remove() call
on the victim which preserves data until the last reference is
closed */
rc = remove_stream_internal(NULL, &newstr, callflags);
if (rc < 0)
FILE_ERROR(ERRNO, rc * 10 - 8);
}
fileop_onrename_internal(&oldstr, is_move ? &old_fileinfo : NULL,
&newinfo.parentinfo, newname);
file_error:
/* for now, there is nothing to fail upon closing the old stream */
if (open1rc >= 0)
close_stream_internal(&oldstr);
/* the 'new' stream could fail to close cleanly because it became
impossible to remove its data if this was an overwrite operation */
if (open2rc >= 0)
{
int rc2 = close_stream_internal(&newstr);
if (rc2 < 0 && rc >= 0)
{
DEBUGF("Success but failed closing new: %d\n", rc2);
rc = rc2 * 10 - 9;
}
}
file_internal_unlock_WRITER();
return rc;
}
/** Extensions **/
/* get the binary size of a file (in bytes) */
off_t filesize(int fildes)
{
struct filestr_desc * const file = GET_FILESTR(READER, fildes);
if (!file)
FILE_ERROR_RETURN(ERRNO, -1);
off_t rc;
file_size_t size = *file->sizep;
if (size > FILE_SIZE_MAX)
FILE_ERROR(EOVERFLOW, -2);
rc = (off_t)size;
file_error:
RELEASE_FILESTR(READER, file);
return rc;
}
/* test if two file descriptors refer to the same file */
int fsamefile(int fildes1, int fildes2)
{
struct filestr_desc * const file1 = GET_FILESTR(WRITER, fildes1);
if (!file1)
FILE_ERROR_RETURN(ERRNO, -1);
int rc = -2;
struct filestr_desc * const file2 = get_filestr(fildes2);
if (file2)
rc = file1->stream.bindp == file2->stream.bindp ? 1 : 0;
RELEASE_FILESTR(WRITER, file1);
return rc;
}
/* tell the relationship of path1 to path2 */
int relate(const char *path1, const char *path2)
{
/* this is basically what rename() does but reduced to the relationship
determination */
DEBUGF("relate(path1=\"%s\",path2=\"%s\")\n", path1, path2);
int rc, open1rc = -1, open2rc = -1;
struct filestr_base str1, str2;
struct path_component_info info1, info2;
file_internal_lock_WRITER();
open1rc = open_stream_internal(path1, FF_ANYTYPE, &str1, &info1);
if (open1rc <= 0)
{
DEBUGF("Failed opening path1: %d\n", open1rc);
if (open1rc < 0)
FILE_ERROR(ERRNO, open1rc * 10 - 1);
else
FILE_ERROR(ENOENT, -1);
}
info2.prefixp = str1.infop;
open2rc = open_stream_internal(path2, FF_ANYTYPE | FF_CHECKPREFIX,
&str2, &info2);
if (open2rc < 0)
{
DEBUGF("Failed opening path2: %d\n", open2rc);
FILE_ERROR(ERRNO, open2rc * 10 - 2);
}
rc = RELATE_DIFFERENT;
if (open2rc > 0)
{
if (str1.bindp == str2.bindp)
rc = RELATE_SAME;
else if (info2.attr & ATTR_PREFIX)
rc = RELATE_PREFIX;
}
else /* open2rc == 0 */
{
/* path1 existing and path2's final part not can only be a prefix or
different */
if (info2.attr & ATTR_PREFIX)
rc = RELATE_PREFIX;
}
file_error:
if (open1rc >= 0)
close_stream_internal(&str1);
if (open2rc >= 0)
close_stream_internal(&str2);
file_internal_unlock_WRITER();
return rc;
}
/* test file or directory existence */
bool file_exists(const char *path)
{
file_internal_lock_WRITER();
bool rc = test_stream_exists_internal(path, FF_ANYTYPE) > 0;
file_internal_unlock_WRITER();
return rc;
}
Reference in a new issue View git blame Copy permalink