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/***************************************************************************

 *             __________               __   ___.

 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___

 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /

 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <

 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \

 *                     \/            \/     \/    \/            \/

 * $Id: file.c 26191 2010-05-20 12:59:12Z funman $

 *

 * Copyright (C) 2002 by Björn Stenberg

 *

 * 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.

 *

 ****************************************************************************/

#include "global.h"

#include "libc/include/errno.h"

#include "libc/include/string.h"

#include "file.h"

#include "fat.h"

#include "dir.h"

#include "util.h"

#include "thread.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.

*/

struct filedesc {

    unsigned char cache[SECTOR_SIZE];

    int cacheoffset; /* invariant: 0 <= cacheoffset <= SECTOR_SIZE */

    long fileoffset;

    long size;

    int attr;

    struct fat_file fatfile;

    struct filedesc* next;

    struct scheduler_thread* process;

    bool write;

    bool dirty;

    bool trunc;

};

static struct mutex file_mutex;

static struct filedesc* openfiles;

static int flush_cache(int fd);

int file_creat(const char *pathname)

{

    return open(pathname, O_WRONLY|O_CREAT|O_TRUNC, 0666);

}

static int open_internal(const char* pathname, int flags, bool use_cache)

{

    DIR* dir;

    struct dirent* entry;

    char pathnamecopy[MAX_PATH];

    char* name;

    struct filedesc* file;

    int rc;

    DEBUGF("open(\"%s\",%d)",pathname,flags);

    if ( pathname[0] != '/' ) {

        DEBUGF("'%s' is not an absolute path.", pathname);

        DEBUGF("Only absolute pathnames supported at the moment");

        errno = EINVAL;

        return -1;

    }

    file = (struct filedesc*)memalign(0x10, sizeof(struct filedesc));

    if (!file)

    {

        errno = EMFILE;

        return -2;

    }

    reownalloc(file, KERNEL_OWNER(KERNEL_OWNER_FILE_HANDLE));

    memset(file, 0, sizeof(struct filedesc));

    file->process = current_thread;

    if (flags & (O_RDWR | O_WRONLY)) {

        file->write = true;

        if (flags & O_TRUNC)

            file->trunc = true;

    }

    strlcpy(pathnamecopy, pathname, sizeof(pathnamecopy));

    /* locate filename */

    name=strrchr(pathnamecopy+1,'/');

    if ( name ) {

        *name = 0; 

        dir = opendir(pathnamecopy);

        *name = '/';

        name++;

    }

    else {

        dir = opendir("/");

        name = pathnamecopy+1;

    }

    if (!dir) {

        DEBUGF("Failed opening dir");

        errno = EIO;

        free(file);

        return -4;

    }

    if(name[0] == 0) {

        DEBUGF("Empty file name");

        errno = EINVAL;

        free(file);

        closedir(dir);

        return -5;

    }

    /* scan dir for name */

    while ((entry = readdir(dir))) {

        if ( !strcasecmp(name, entry->d_name) ) {

            fat_open(IF_MV2(dir->fatdir.file.volume,)

                     entry->startcluster,

                     &(file->fatfile),

                     &(dir->fatdir));

            file->size = file->trunc ? 0 : entry->size;

            file->attr = entry->attribute;

            break;

        }

    }

    if ( !entry ) {

        DEBUGF("Didn't find file %s",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",name,pathnamecopy);

                errno = EIO;

                free(file);

                closedir(dir);

                return rc * 10 - 6;

            }

            file->size = 0;

            file->attr = 0;

        }

        else {

            DEBUGF("Couldn't find %s in %s",name,pathnamecopy);

            errno = ENOENT;

            free(file);

            closedir(dir);

            return -7;

        }

    } else {

        if(file->attr & FAT_ATTR_DIRECTORY) {

            errno = EISDIR;

            free(file);

            closedir(dir);

            return -8;

        }

    }

    closedir(dir);

    file->cacheoffset = -1;

    file->fileoffset = 0;

    if (file->write && (flags & O_APPEND)) {

        rc = lseek((int)file,0,SEEK_END);

        if (rc < 0 )

        {

            free(file);

            return rc * 10 - 9;

        }

    }

    mutex_lock(&file_mutex, TIMEOUT_BLOCK);

    file->next = openfiles;

    openfiles = file;

    mutex_unlock(&file_mutex);

    return (int)file;

}

int file_open(const char* pathname, int flags)

{

    /* By default, use the dircache if available. */

    return open_internal(pathname, flags, true);

}

void reown_file(int fd, struct scheduler_thread* owner)

{

    struct filedesc* f = (struct filedesc*)fd;

    f->process = owner;

}

int close(int fd)

{

    int rc = 0;

    struct filedesc* f = (struct filedesc*)fd;

    DEBUGF("close(%d)", fd);

    if (!f)

    {

        errno = EBADF;

        return -2;

    }

    if (f->write)

    {

        rc = fsync(fd);

        if (rc < 0)

            return rc * 10 - 3;

    }

    mutex_lock(&file_mutex, TIMEOUT_BLOCK);

    if (openfiles == f) openfiles = openfiles->next;

    else

        for (f = openfiles; f; f = f->next)

            if ((int)(f->next) == fd)

                f->next = f->next->next;

    mutex_unlock(&file_mutex);

    free((void*)fd);

    return 0;

}

int close_all_of_process(struct scheduler_thread* process)

{

    struct filedesc* f;

    struct filedesc* prev;

    int closed = 0;

    mutex_lock(&file_mutex, TIMEOUT_BLOCK);

    while (openfiles && openfiles->process == process)

    {

        prev = openfiles;

        openfiles = openfiles->next;

        if (openfiles->write) fsync((int)openfiles);

        free(prev);

        closed++;

    }

    for (f = openfiles; f; f = f->next)

        while (f->next && f->next->process == process)

        {

            prev = f->next;

            f->next = f->next->next;

            free(prev);

            closed++;

        }

    mutex_unlock(&file_mutex);

    return closed; /* return how many we did */

}

int fsync(int fd)

{

    struct filedesc* file = (struct filedesc*)fd;

    int rc = 0;

    DEBUGF("fsync(%d)", fd);

    if (!file) {

        errno = EBADF;

        return -2;

    }

    if (file->write) {

        /* flush sector cache */

        if ( file->dirty ) {

            rc = flush_cache(fd);

            if (rc < 0)

            {

                /* when failing, try to close the file anyway */

                fat_closewrite(&(file->fatfile), file->size, file->attr);

                return rc * 10 - 3;

            }

        }

        /* truncate? */

        if (file->trunc) {

            rc = ftruncate(fd, file->size);

            if (rc < 0)

            {

                /* when failing, try to close the file anyway */

                fat_closewrite(&(file->fatfile), file->size, file->attr);

                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;

    /* Can't use dircache now, because we need to access the fat structures. */

    int fd = open_internal(name, O_WRONLY, false);

    if ( fd < 0 )

        return fd * 10 - 1;

    struct filedesc* file = (struct filedesc*)fd;

    rc = fat_remove(&(file->fatfile));

    if ( rc < 0 ) {

        DEBUGF("Failed removing file: %d", 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;

    DIR* dir;

    char* nameptr;

    char* dirptr;

    struct filedesc* file;

    char newpath2[MAX_PATH];

    /* verify new path does not already exist */

    /* If it is a directory, errno == EISDIR if the name exists */

    fd = open(newpath, O_RDONLY);

    if ( fd >= 0 || errno == EISDIR) {

        close(fd);

        errno = EBUSY;

        return -1;

    }

    close(fd);

    fd = open_internal(path, O_RDONLY, false);

    if ( fd < 0 ) {

        errno = EIO;

        return fd * 10 - 2;

    }

    /* extract new file name */

    nameptr = strrchr(newpath,'/');

    if (nameptr)

        nameptr++;

    else {

        close(fd);

        return - 3;

    }

    /* Extract new path */

    strcpy(newpath2, newpath);

    dirptr = strrchr(newpath2,'/');

    if(dirptr)

        *dirptr = 0;

    else {

        close(fd);

        return - 4;

    }

    dirptr = newpath2;

    if(strlen(dirptr) == 0) {

        dirptr = "/";

    }

    dir = opendir(dirptr);

    if(!dir) {

        close(fd);

        return - 5;

    }

    file = (struct filedesc*)fd;

    rc = fat_rename(&file->fatfile, &dir->fatdir, nameptr,

                    file->size, file->attr);

#ifdef HAVE_MULTIVOLUME

    if ( rc == -1) {

        close(fd);

        closedir(dir);

        DEBUGF("Failed renaming file across volumnes: %d", rc);

        errno = EXDEV;

        return -6;

    }

#endif

    if ( rc < 0 ) {

        close(fd);

        closedir(dir);

        DEBUGF("Failed renaming file: %d", rc);

        errno = EIO;

        return rc * 10 - 7;

    }

    rc = close(fd);

    if (rc<0) {

        closedir(dir);

        errno = EIO;

        return rc * 10 - 8;

    }

    rc = closedir(dir);

    if (rc<0) {

        errno = EIO;

        return rc * 10 - 9;

    }

    return 0;

}

int ftruncate(int fd, off_t size)

{

    int rc, sector;

    struct filedesc* file = (struct filedesc*)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 = (struct filedesc*)fd;

    long sector = file->fileoffset / SECTOR_SIZE;

    DEBUGF("Flushing dirty sector cache");

    /* 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, long count, bool write)

{

    long sectors;

    long i;

    long nread=0;

    struct filedesc* file;

    int rc, rc2;

    file = (struct filedesc*)fd;

    if (!file) {

        errno = EBADF;

        return -1;

    }

    if(file->attr & FAT_ATTR_DIRECTORY) {

        errno = EISDIR;

        return -1;

    }

    DEBUGF( "readwrite(%d,%lx,%ld,%s)",

             fd,(long)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 offs = file->cacheoffset;

        int headbytes = MIN(count, SECTOR_SIZE - offs);

        if (write) {

            memcpy( file->cache + offs, buf, headbytes );

            file->dirty = true;

        }

        else {

            memcpy( buf, file->cache + offs, headbytes );

        }

        if (offs + headbytes == SECTOR_SIZE) {

            if (file->dirty) {

                rc = flush_cache(fd);

                if ( rc < 0 ) {

                    errno = EIO;

                    return rc * 10 - 2;

                }

            }

            file->cacheoffset = -1;

        }

        else {

            file->cacheoffset += headbytes;

        }

        nread = headbytes;

        count -= headbytes;

    }

    /* If the buffer has been modified, either it has been flushed already

     * (if (offs+headbytes == SECTOR_SIZE)...) or does not need to be (no

     * more data to follow in this call). Do NOT flush here. */

    /* read/write whole sectors right into/from the supplied buffer */

    sectors = count / SECTOR_SIZE;

    rc = 0;

    if ( sectors ) {

        if (((uint32_t)buf + nread) & (CACHEALIGN_SIZE - 1))

            for (i = 0; i < sectors; i++)

            {

                if (write) memcpy(file->cache, buf+nread+i*SECTOR_SIZE, SECTOR_SIZE);

                rc2 = fat_readwrite(&(file->fatfile), 1, file->cache, write );

                if (rc2 < 0)

                {

                    rc = rc2;

                    break;

                }

                else rc += rc2;

                if (!write) memcpy(buf+nread+i*SECTOR_SIZE, file->cache, SECTOR_SIZE);

            }

        else rc = fat_readwrite(&(file->fatfile), sectors, (unsigned char*)buf+nread, write );

        if ( rc < 0 ) {

            DEBUGF("Failed read/writing %ld sectors",sectors);

            errno = EIO;

            if(write && file->fatfile.eof) {

                DEBUGF("No space left on device");

                errno = ENOSPC;

            } else {

                file->fileoffset += nread;

            }

            file->cacheoffset = -1;

            /* adjust file size to length written */

            if ( write && file->fileoffset > file->size )

            {

                file->size = file->fileoffset;

            }

            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 */

                DEBUGF("Copy-back tail cache");

                rc = fat_readwrite(&(file->fatfile), 1, file->cache, false );

                if ( rc < 0 ) {

                    DEBUGF("Failed writing");

                    errno = EIO;

                    file->fileoffset += nread;

                    file->cacheoffset = -1;

                    /* adjust file size to length written */

                    if ( file->fileoffset > file->size )

                    {

                        file->size = file->fileoffset;

                    }

                    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");

                    errno = EIO;

                    file->fileoffset += nread;

                    file->cacheoffset = -1;

                    /* adjust file size to length written */

                    if ( file->fileoffset > file->size )

                    {

                        file->size = file->fileoffset;

                    }

                    return nread ? nread : rc * 10 - 6;

                }

            }

            memcpy( file->cache, (unsigned char*)buf + nread, count );

            file->dirty = true;

        }

        else {

            rc = fat_readwrite(&(file->fatfile), 1, file->cache,false);

            if (rc < 1 ) {

                DEBUGF("Failed caching sector");

                errno = EIO;

                file->fileoffset += nread;

                file->cacheoffset = -1;

                return nread ? nread : rc * 10 - 7;

            }

            memcpy( (unsigned char*)buf + nread, file->cache, count );

        }

        nread += count;

        file->cacheoffset = count;

    }

    file->fileoffset += nread;

    DEBUGF("fileoffset: %ld", 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 (!((struct filedesc*)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)

{

    off_t pos;

    long newsector;

    long oldsector;

    int sectoroffset;

    int rc;

    struct filedesc* file = (struct filedesc*)fd;

    DEBUGF("lseek(%d,%ld,%d)",fd,offset,whence);

    if (!file) {

        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;

}

off_t filesize(int fd)

{

    struct filedesc* file = (struct filedesc*)fd;

    if (!file) {

        errno = EBADF;

        return -1;

    }

    return file->size;

}

#ifdef HAVE_HOTSWAP

/* release all file handles on a given volume "by force", to avoid leaks */

int release_files(int volume)

{

    struct filedesc* prev;

    int closed = 0;

    mutex_lock(&file_mutex, TIMEOUT_BLOCK);

#ifdef HAVE_MULTIVOLUME

    struct filedesc* f;

    while (openfiles && openfiles->fatfile.volume == volume)

    {

        prev = openfiles;

        openfiles = openfiles->next;

        free(prev);

        closed++;

    }

    for (f = openfiles; f; f = f->next)

        while (f->next && f->next->fatfile.volume == volume)

        {

            prev = f->next;

            f->next = f->next->next;

            free(prev);

            closed++;

        }

#else

    (void)volume;

    while (openfiles)

    {

        prev = openfiles;

        openfiles = openfiles->next;

        free(prev);

        closed++;

    }

#endif

    mutex_unlock(&file_mutex);

    return closed; /* return how many we did */

}

#endif /* #ifdef HAVE_HOTSWAP */