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//==========================================================================

//

//      file.cxx

//

//      Fileio file operations

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos 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 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

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// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):           nickg

// Contributors:        nickg

// Date:                2000-05-25

// Purpose:             Fileio file operations

// Description:         These are the functions that operate on files as a whole,

//                      such as open(), creat(), mkdir() etc.

//              

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <pkgconf/hal.h>

#include <pkgconf/io_fileio.h>

#include <pkgconf/isoinfra.h>

#include <cyg/infra/cyg_trac.h>        // tracing macros

#include <cyg/infra/cyg_ass.h>         // assertion macros

#include <string.h>                    // string functions

#include <dirent.h>

#include <stdio.h>                     // stdin, stdout, stderr

#include "fio.h"                       // Private header

//==========================================================================

// Implement filesystem locking protocol. 

#define LOCK_FS( _mte_ )  {                             \

   CYG_ASSERT(_mte_ != NULL, "Bad mount table entry");  \

   cyg_fs_lock( _mte_, (_mte_)->fs->syncmode);          \

}

#define UNLOCK_FS( _mte_ ) cyg_fs_unlock( _mte_, (_mte_)->fs->syncmode)

//==========================================================================

// A local strcpy clone that returns a pointer to the end of the copied

// string, not the beginning.

static char *my_strcpy( char *s1, const char *s2 )

{

    while( (*s1++ = *s2++) != 0);

    return s1-1;

}

//==========================================================================

// Compare a pathname fragment with an element in a pathname. This

// deals with zero or separator termination and avoids substring

// matches.

static int pathcmp( const char *path, const char *name )

{

    while( *path == *name && *path != '\0' )

        path++, name++;

    if( *name != '\0' ) return false;

    if( *path == '/' || *path == '\0' ) return true;

    return false;

}

//==========================================================================

// CWD support

#ifdef CYGPKG_IO_FILEIO_TRACK_CWD

// buffer for storing CWD path

static char cwd[PATH_MAX];

static size_t cwd_size = 0;

static void update_cwd( cyg_mtab_entry *mte, cyg_dir dir, const char *path )

{

    char *p = cwd;

    if( mte != cdir_mtab_entry || dir != cdir_dir )

    {

        // Here, the path is relative to the root of the filesystem,

        // or in a totally new filesystem, initialize the cwd with the

        // mount point name of the filesystem.

        p = my_strcpy( p, mte->name );

    }

    else p = cwd+cwd_size;

    // We must now copy the path into the cwd buffer while dealing

    // with any "." and ".."  components textually.

    while( *path != '\0' )

    {

        // skip any stray directory separators.

        if( *path == '/' ) path++;

        // Look for a "." entry and just ignore it.

        if( pathcmp( path, "." ) )

        {

            path++;

            continue;

        }

        // Look for a ".." entry. If found, chew off the last cwd

        // entry.

        if( pathcmp( path, ".." ) )

        {

            while( *(--p) != '/' );     // back up to last '/'

            path += 2;                  // skip "..".

            continue;

        }

        // Otherwise just copy the name fragment over to the cwd.

        if( *(p-1) != '/' )

            *p++ = '/';        // add a directory separator

        while( *path != '/' && *path != '\0' )

            *p++ = *path++;

    }

    // Zero terminate the cwd.

    *p = '\0';

    // update size

    cwd_size = p-cwd;

}

#else

#ifdef CYGPKG_KERNEL

static Cyg_Mutex getcwd_lock CYGBLD_ATTRIB_INIT_PRI(CYG_INIT_IO_FS);

#endif

#endif

//==========================================================================

// Open a file

__externC int open( const char *path, int oflag, ... )

{

    FILEIO_ENTRY();

    // we want to be sure we pull in stdin/out/err, so they can be

    // assigned to fds 0, 1 and 2

#ifdef CYGINT_ISO_STDIO_STREAMS

    CYG_REFERENCE_OBJECT(stdin);

    CYG_REFERENCE_OBJECT(stdout);

    CYG_REFERENCE_OBJECT(stderr);

#endif

    CYG_CANCELLATION_POINT;

    int ret = 0;

    int fd;

    cyg_file *file;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    // At least one of O_RDONLY, O_WRONLY, O_RDWR must be provided

    if( (oflag & O_RDWR) == 0 )

        FILEIO_RETURN(EINVAL);

    fd = cyg_fd_alloc(0);

    if( fd < 0 )

        FILEIO_RETURN(EMFILE);

    file = cyg_file_alloc();

    if( file == NULL )

    {

        cyg_fd_free(fd);

        FILEIO_RETURN(ENFILE);

    }

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

    {

        cyg_fd_free(fd);

        cyg_file_free(file);

        FILEIO_RETURN(ENOENT);

    }

    LOCK_FS( mte );

    ret = mte->fs->open( mte, dir, name, oflag, file );

    UNLOCK_FS( mte );

    if( 0 != ret )

    {

        cyg_fd_free(fd);

        cyg_file_free(file);

        FILEIO_RETURN(ret);

    }

    file->f_mte = mte;

    file->f_syncmode = mte->fs->syncmode;

    cyg_fd_assign( fd, file );

    FILEIO_RETURN_VALUE(fd);

}

//==========================================================================

// create a file

__externC int creat( const char *path, mode_t mode )

{

    return open( path, O_WRONLY | O_CREAT | O_TRUNC, mode );

}

//==========================================================================

// Unlink/remove a file

__externC int unlink( const char *path )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    LOCK_FS( mte );

    ret = mte->fs->unlink( mte, dir, name );

    UNLOCK_FS( mte );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Make a directory

__externC int mkdir( const char *path, mode_t mode )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    mode=mode;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    LOCK_FS( mte );

    ret = mte->fs->mkdir( mte, dir, name );

    UNLOCK_FS( mte );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Remove a directory

__externC int rmdir( const char *path )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    LOCK_FS( mte );

    ret = mte->fs->rmdir( mte, dir, name );

    UNLOCK_FS( mte );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Rename a file

__externC int rename( const char *path1, const char *path2 )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte1 = cdir_mtab_entry;

    cyg_mtab_entry *mte2 = cdir_mtab_entry;

    cyg_dir dir1 = cdir_dir;

    cyg_dir dir2 = cdir_dir;

    const char *name1 = path1;

    const char *name2 = path2;

    ret = cyg_mtab_lookup( &dir1, &name1, &mte1 );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    ret = cyg_mtab_lookup( &dir2, &name2, &mte2 );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    // Cannot rename between different filesystems

    if( mte1 != mte2 )

        FILEIO_RETURN(EXDEV);

    LOCK_FS( mte1 );

    ret = mte1->fs->rename( mte1, dir1, name1, dir2, name2 );

    UNLOCK_FS( mte1 );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Create a link from an existing file (path1) to a new one (path2)

__externC int link( const char *path1, const char *path2 )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte1 = cdir_mtab_entry;

    cyg_mtab_entry *mte2 = cdir_mtab_entry;

    cyg_dir dir1 = cdir_dir;

    cyg_dir dir2 = cdir_dir;

    const char *name1 = path1;

    const char *name2 = path2;

    ret = cyg_mtab_lookup( &dir1, &name1, &mte1 );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    ret = cyg_mtab_lookup( &dir2, &name2, &mte2 );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    // Cannot hard-link between different filesystems

    if( mte1 != mte2 )

        FILEIO_RETURN(EXDEV);

    LOCK_FS( mte1 );

    ret = mte1->fs->link( mte1, dir1, name1, dir2, name2, CYG_FSLINK_HARD );

    UNLOCK_FS( mte1 );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Change current directory

__externC int chdir( const char *path )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    cyg_dir newdir;

    const char *name = path;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    LOCK_FS(mte);

    ret = mte->fs->chdir( mte, dir, name, &newdir );

    UNLOCK_FS(mte);

    if( 0 != ret )

        FILEIO_RETURN(ret);

#ifdef CYGPKG_IO_FILEIO_TRACK_CWD

    update_cwd( mte, dir, name );

#endif

    if( cdir_mtab_entry != NULL && cdir_dir != CYG_DIR_NULL )

    {

        // Now detach from current cdir. We call the current directory's

        // chdir routine with a NULL dir_out pointer.

        LOCK_FS(cdir_mtab_entry);

        ret = cdir_mtab_entry->fs->chdir( cdir_mtab_entry, cdir_dir, NULL, NULL );

        UNLOCK_FS(cdir_mtab_entry);

        // We really shouldn't get an error here.

        if( 0 != ret )

            FILEIO_RETURN(ret);

    }

    cdir_mtab_entry = mte;

    cdir_dir = newdir;

    FILEIO_RETURN(ENOERR);

}

//==========================================================================

// Get file statistics

__externC int stat( const char *path, struct stat *buf )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    LOCK_FS( mte );

    ret = mte->fs->stat( mte, dir, name, buf );

    UNLOCK_FS( mte );

    FILEIO_RETURN(ret);

}

//==========================================================================

// Get file configurable pathname variables

__externC long pathconf( const char *path, int vname )

{

    FILEIO_ENTRY();

    int ret = 0;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    const char *name = path;

    ret = cyg_mtab_lookup( &dir, &name, &mte );

    if( 0 != ret )

        FILEIO_RETURN(ENOENT);

    struct cyg_pathconf_info info;

    info.name = vname;

    info.value = 0;

    LOCK_FS( mte );

    ret = mte->fs->getinfo( mte, dir, name,

                            FS_INFO_CONF, (char *)&info, sizeof(info) );

    UNLOCK_FS( mte );

    if( 0 != ret )

        FILEIO_RETURN(ret);

    FILEIO_RETURN_VALUE(info.value);

}

//==========================================================================

// Access() function.

// This simply piggybacks onto stat().

extern int      access(const char *path, int amode)

{

    FILEIO_ENTRY();

    int ret;

    struct stat buf;

    ret = stat( path, &buf );

    // Translate not found into EACCES if the F_OK bit is

    // set.

    if( (amode & F_OK) && (ret < 0) && (errno == ENOENT) )

        FILEIO_RETURN(EACCES);

    // All other errors go straight back to the user.

    if( ret < 0 )

        FILEIO_RETURN_VALUE(ret);

    // At present we do not have any access modes, so there is nothing

    // to test.  Just return success for all access modes.

    FILEIO_RETURN(ENOERR);

}

//==========================================================================

// getcwd()

__externC char *getcwd( char *buf, size_t size )

{

    FILEIO_ENTRY();

    int err = ENOERR;

    cyg_mtab_entry *mte = cdir_mtab_entry;

    cyg_dir dir = cdir_dir;

    cyg_getcwd_info info;

    if( size == 0 )

    {

        errno = EINVAL;

        FILEIO_RETURN_VALUE(NULL);

    }

    info.buf = buf;

    info.size = size;

    LOCK_FS( mte );

    err = mte->fs->getinfo( mte, dir, "",

                            FS_INFO_GETCWD, (char *)&info, sizeof(info) );

    UNLOCK_FS( mte );

    if( err == ENOERR )

        FILEIO_RETURN_VALUE(buf);

    // Attempting to use filesystem support for getcwd() has

    // failed.

#ifdef CYGPKG_IO_FILEIO_TRACK_CWD

    // If this option is set, the current directory path has been

    // tracked in chdir(). Just report that value here.

    if( size < cwd_size+1 )

    {

        errno = ERANGE;

        FILEIO_RETURN_VALUE(NULL);

    }

    char *p = my_strcpy( buf, cwd );

    *p = '\0';

#else

    // As a fallback we try to use ".." entries in the directory tree

    // to climb back up to the root.  Because we cannot assume that

    // any filesystem can handle more than one directory pointer we

    // have to do the climbing textually, by manufacturing a path name

    // consisting of ".."s. At each level we then scan the parent

    // directory looking for the entry for the lower level directory

    // by matching st_ino values. This is not guaranteed to work at

    // all since there is no requirement on filesystems to support "."

    // and "..", or for them to report distinct inode values in

    // stat().

    static char ddbuf[PATH_MAX];

    char *p = buf+size-1;

    int ddbufpos;

    // Claim lock to serialize use of ddbuf.

    FILEIO_MUTEX_LOCK(getcwd_lock);

    // Initialize ddbuf with ".".

    ddbuf[0] = '.';

    ddbuf[1] = '\0';

    ddbufpos = 1;

    // Start result buffer with a zero terminator. We accumulate the

    // path name in the top end of the result buffer.

    *p = '\0';

    for(;;)

    {

        struct stat sdbuf;

        struct stat sddbuf;

        // Get status for "." and "..". If the filesystem does not

        // support these, then this whole function will fail here.

        err = stat( ddbuf, &sdbuf );

        if( err < 0 ) break;

        ddbuf[ddbufpos++] = '/';

        ddbuf[ddbufpos++] = '.';

        ddbuf[ddbufpos++] = '.';

        ddbuf[ddbufpos] = '\0';

        err = stat( ddbuf, &sddbuf );

        if( err < 0 ) break;

        // See whether we are at the root. This will be true when

        // the inode numbers of "." and ".." are the same.

        if( sdbuf.st_ino == sddbuf.st_ino )

            break;

        // We now need to find an entry in the ".." directory that

        // matches the inode number of ".".

        struct dirent de;

        DIR *d = opendir( ddbuf );

        if( d == NULL )

        {

            err = -1;

            break;

        }

        for(;;)

        {

            struct dirent *res;

            struct stat objstat;

            int i;

            err = readdir_r( d, &de, &res );

            if( err < 0 || res == NULL ) break;

            // Skip "." and ".." entries.

            if( pathcmp( de.d_name, "." ) || pathcmp( de.d_name, ".." ) )

                continue;

            // Tack the name of the directory entry on to the ddbuf

            // and stat the object.

            ddbuf[ddbufpos] = '/';

            for( i = 0; de.d_name[i] != '\0'; i++ )

                ddbuf[ddbufpos+i+1] = de.d_name[i];

            ddbuf[ddbufpos+i+1] = '\0';

            // Take a look at it

            err = stat( ddbuf, &objstat );

            if( err < 0 ) break;

            // Cast out directories

            if( !S_ISDIR(objstat.st_mode) )

                continue;

            // We have a directory. Compare its inode with that of "."

            // and if they are the same, we have found our entry.

            if( sdbuf.st_ino == objstat.st_ino )

                break;

        }

        ddbuf[ddbufpos] = '\0'; // reterminate ddbuf

        closedir( d );

        // Halt on any errors.

        if( err < 0 )