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657e1bf66b9406cd4c18af1265443e9ebf006f39
rtems/c/src/lib/libc/memfile.c
Joel Sherrill 657e1bf66b Added initial cut at miniIMFS which leaves out memfile and directory 
readdir support.  The next step is to add a mount table and configure
either the miniIMFS or the full IMFS at the application level.
1999-10-26 20:17:13 +00:00

1059 lines
22 KiB
C
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/*
* IMFS Device Node Handlers
*
* This file contains the set of handlers used to process operations on
* IMFS memory file nodes. The memory files are created in memory using
* malloc'ed memory. Thus any data stored in one of these files is lost
* at system shutdown unless special arrangements to copy the data to
* some type of non-volailte storage are made by the application.
*
* COPYRIGHT (c) 1989-1998.
* On-Line Applications Research Corporation (OAR).
* Copyright assigned to U.S. Government, 1994.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <rtems.h>
#include <rtems/libio.h>
#include "imfs.h"
#include "libio_.h"
#define MEMFILE_STATIC
/*
* Set of operations handlers for operations on memfile entities.
*/
rtems_filesystem_file_handlers_r IMFS_memfile_handlers = {
memfile_open,
memfile_close,
memfile_read,
memfile_write,
memfile_ioctl,
memfile_lseek,
IMFS_stat,
IMFS_fchmod,
memfile_ftruncate,
NULL, /* fpathconf */
NULL, /* fsync */
IMFS_fdatasync,
IMFS_fcntl
};
/*
* Prototypes of private routines
*/
MEMFILE_STATIC int IMFS_memfile_extend(
IMFS_jnode_t *the_jnode,
off_t new_length
);
MEMFILE_STATIC int IMFS_memfile_addblock(
IMFS_jnode_t *the_jnode,
unsigned int block
);
MEMFILE_STATIC int IMFS_memfile_remove_block(
IMFS_jnode_t *the_jnode,
unsigned int block
);
MEMFILE_STATIC block_p *IMFS_memfile_get_block_pointer(
IMFS_jnode_t *the_jnode,
unsigned int block,
int malloc_it
);
MEMFILE_STATIC int IMFS_memfile_read(
IMFS_jnode_t *the_jnode,
off_t start,
unsigned char *destination,
unsigned int length
);
MEMFILE_STATIC int IMFS_memfile_write(
IMFS_jnode_t *the_jnode,
off_t start,
const unsigned char *source,
unsigned int length
);
void *memfile_alloc_block(void);
void memfile_free_block(
void *memory
);
/*
* memfile_open
*
* This routine processes the open() system call. Note that there is
* nothing special to be done at open() time.
*/
int memfile_open(
rtems_libio_t *iop,
const char *pathname,
unsigned32 flag,
unsigned32 mode
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
return 0;
}
/*
* memfile_close
*
* This routine processes the close() system call. Note that there is
* nothing to flush or memory to free at this point.
*/
int memfile_close(
rtems_libio_t *iop
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
return 0;
}
/*
* memfile_read
*
* This routine processes the read() system call.
*/
int memfile_read(
rtems_libio_t *iop,
void *buffer,
unsigned32 count
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
return IMFS_memfile_read( the_jnode, iop->offset, buffer, count );
}
/*
* memfile_write
*
* This routine processes the write() system call.
*/
int memfile_write(
rtems_libio_t *iop,
const void *buffer,
unsigned32 count
)
{
IMFS_jnode_t *the_jnode;
int status;
the_jnode = iop->file_info;
status = IMFS_memfile_write( the_jnode, iop->offset, buffer, count );
iop->size = the_jnode->info.file.size;
return status;
}
/*
* memfile_ioctl
*
* This routine processes the ioctl() system call.
*
* NOTE: No ioctl()'s are supported for in-memory files.
*/
int memfile_ioctl(
rtems_libio_t *iop,
unsigned32 command,
void *buffer
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
return 0;
}
/*
* memfile_lseek
*
* This routine processes the lseek() system call.
*/
int memfile_lseek(
rtems_libio_t *iop,
off_t offset,
int whence
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
if (IMFS_memfile_extend( the_jnode, iop->offset ))
set_errno_and_return_minus_one( ENOSPC );
iop->size = the_jnode->info.file.size;
return iop->offset;
}
/*
* memfile_stat
*
* This IMFS_stat() can be used.
*/
/*
* memfile_ftruncate
*
* This routine processes the ftruncate() system call.
*/
int memfile_ftruncate(
rtems_libio_t *iop,
off_t length
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->file_info;
/*
* POSIX 1003.1b does not specify what happens if you truncate a file
* and the new length is greater than the current size. We treat this
* as an extend operation.
*/
if ( length > the_jnode->info.file.size )
return IMFS_memfile_extend( the_jnode, length );
/*
* The in-memory files do not currently reclaim memory until the file is
* deleted. So we leave the previously allocated blocks in place for
* future use and just set the length.
*/
the_jnode->info.file.size = length;
iop->size = the_jnode->info.file.size;
IMFS_update_atime( the_jnode );
return 0;
}
/*
* IMFS_memfile_extend
*
* This routine insures that the in-memory file is of the length
* specified. If necessary, it will allocate memory blocks to
* extend the file.
*/
MEMFILE_STATIC int IMFS_memfile_extend(
IMFS_jnode_t *the_jnode,
off_t new_length
)
{
unsigned int block;
unsigned int new_blocks;
unsigned int old_blocks;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
set_errno_and_return_minus_one( EIO );
if ( new_length >= IMFS_MEMFILE_MAXIMUM_SIZE )
set_errno_and_return_minus_one( EINVAL );
if ( new_length <= the_jnode->info.file.size )
return 0;
/*
* Calculate the number of range of blocks to allocate
*/
new_blocks = new_length / IMFS_MEMFILE_BYTES_PER_BLOCK;
old_blocks = the_jnode->info.file.size / IMFS_MEMFILE_BYTES_PER_BLOCK;
/*
* Now allocate each of those blocks.
*/
for ( block=old_blocks ; block<=new_blocks ; block++ ) {
if ( IMFS_memfile_addblock( the_jnode, block ) ) {
for ( ; block>=old_blocks ; block-- ) {
IMFS_memfile_remove_block( the_jnode, block );
}
set_errno_and_return_minus_one( ENOSPC );
}
}
/*
* Set the new length of the file.
*/
the_jnode->info.file.size = new_length;
return 0;
}
/*
* IMFS_memfile_addblock
*
* This routine adds a single block to the specified in-memory file.
*/
MEMFILE_STATIC int IMFS_memfile_addblock(
IMFS_jnode_t *the_jnode,
unsigned int block
)
{
block_p memory;
block_p *block_entry_ptr;
assert( the_jnode );
if ( !the_jnode )
set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
set_errno_and_return_minus_one( EIO );
block_entry_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 1 );
if ( *block_entry_ptr )
return 0;
#if 0
printf( "%d %p", block, block_entry_ptr );
fflush(stdout);
#endif
memory = memfile_alloc_block();
assert( memory );
if ( !memory )
return 1;
*block_entry_ptr = memory;
return 0;
}
/*
* IMFS_memfile_remove_block
*
* This routine removes the specified block from the in-memory file.
*
* NOTE: This is a support routine and is called only to remove
* the last block or set of blocks in a file. Removing a
* block from the middle of a file would be exceptionally
* dangerous and the results unpredictable.
*/
MEMFILE_STATIC int IMFS_memfile_remove_block(
IMFS_jnode_t *the_jnode,
unsigned int block
)
{
block_p *block_entry_ptr;
block_p ptr;
block_entry_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
ptr = *block_entry_ptr;
*block_entry_ptr = 0;
memfile_free_block( ptr );
return 1;
}
/*
* memfile_free_blocks_in_table
*
* This is a support routine for IMFS_memfile_remove. It frees all the
* blocks in one of the indirection tables.
*/
void memfile_free_blocks_in_table(
block_p **block_table,
int entries
)
{
int i;
block_p *b;
/*
* Perform internal consistency checks
*/
assert( block_table );
if ( !block_table )
return;
/*
* Now go through all the slots in the table and free the memory.
*/
b = *block_table;
for ( i=0 ; i<entries ; i++ ) {
if ( b[i] ) {
memfile_free_block( b[i] );
b[i] = 0;
}
}
/*
* Now that all the blocks in the block table are free, we can
* free the block table itself.
*/
memfile_free_block( *block_table );
*block_table = 0;
}
/*
* IMFS_memfile_remove
*
* This routine frees all memory associated with an in memory file.
*
* NOTE: This is an exceptionally conservative implementation.
* It will check EVERY pointer which is non-NULL and insure
* any child non-NULL pointers are freed. Optimistically, all that
* is necessary is to scan until a NULL pointer is found. There
* should be no allocated data past that point.
*
* In experimentation on the powerpc simulator, it was noted
* that using blocks which held 128 slots versus 16 slots made
* a significant difference in the performance of this routine.
*
* Regardless until the IMFS implementation is proven, it
* is better to stick to simple, easy to understand algorithms.
*/
int IMFS_memfile_remove(
IMFS_jnode_t *the_jnode
)
{
IMFS_memfile_t *info;
int i;
int j;
unsigned int to_free;
block_p *p;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
set_errno_and_return_minus_one( EIO );
/*
* Eventually this could be set smarter at each call to
* memfile_free_blocks_in_table to greatly speed this up.
*/
to_free = IMFS_MEMFILE_BLOCK_SLOTS;
/*
* Now start freeing blocks in this order:
* + indirect
* + doubly indirect
* + triply indirect
*/
info = &the_jnode->info.file;
if ( info->indirect ) {
memfile_free_blocks_in_table( &info->indirect, to_free );
}
if ( info->doubly_indirect ) {
for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) {
if ( info->doubly_indirect[i] ) {
memfile_free_blocks_in_table(
(block_p **)&info->doubly_indirect[i], to_free );
}
}
memfile_free_blocks_in_table( &info->doubly_indirect, to_free );
}
if ( info->triply_indirect ) {
for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) {
p = (block_p *) info->triply_indirect[i];
for ( j=0 ; j<IMFS_MEMFILE_BLOCK_SLOTS ; j++ ) {
if ( p[j] ) {
memfile_free_blocks_in_table( (block_p **)&p[j], to_free);
}
}
memfile_free_blocks_in_table(
(block_p **)&info->triply_indirect[i], to_free );
}
memfile_free_blocks_in_table(
(block_p **)&info->triply_indirect, to_free );
}
return 0;
}
/*
* IMFS_memfile_read
*
* This routine read from memory file pointed to by the_jnode into
* the specified data buffer specified by destination. The file
* is NOT extended. An offset greater than the length of the file
* is considered an error. Read from an offset for more bytes than
* are between the offset and the end of the file will result in
* reading the data between offset and the end of the file (truncated
* read).
*/
MEMFILE_STATIC int IMFS_memfile_read(
IMFS_jnode_t *the_jnode,
off_t start,
unsigned char *destination,
unsigned int length
)
{
block_p *block_ptr;
unsigned int block;
unsigned int my_length;
unsigned int to_copy = 0;
unsigned int last_byte;
unsigned int copied;
unsigned int start_offset;
unsigned char *dest;
dest = destination;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
set_errno_and_return_minus_one( EIO );
/*
* Error checks on arguments
*/
assert( dest );
if ( !dest )
set_errno_and_return_minus_one( EINVAL );
/*
* If there is nothing to read, then quick exit.
*/
my_length = length;
if ( !my_length )
set_errno_and_return_minus_one( EINVAL );
/*
* If the last byte we are supposed to read is past the end of this
* in memory file, then shorten the length to read.
*/
last_byte = start + length;
if ( last_byte > the_jnode->info.file.size )
my_length = the_jnode->info.file.size - start;
copied = 0;
/*
* Three phases to the read:
* + possibly the last part of one block
* + all of zero of more blocks
* + possibly the first part of one block
*/
/*
* Phase 1: possibly the last part of one block
*/
start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK;
block = start / IMFS_MEMFILE_BYTES_PER_BLOCK;
if ( start_offset ) {
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset;
if ( to_copy > my_length )
to_copy = my_length;
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ start_offset ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 2: all of zero of more blocks
*/
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK;
while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 3: possibly the first part of one block
*/
assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK );
if ( my_length ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], my_length );
copied += my_length;
}
IMFS_update_atime( the_jnode );
return copied;
}
/*
* IMFS_memfile_write
*
* This routine writes the specified data buffer into the in memory
* file pointed to by the_jnode. The file is extended as needed.
*/
MEMFILE_STATIC int IMFS_memfile_write(
IMFS_jnode_t *the_jnode,
off_t start,
const unsigned char *source,
unsigned int length
)
{
block_p *block_ptr;
unsigned int block;
int status;
unsigned int my_length;
unsigned int to_copy = 0;
unsigned int last_byte;
unsigned int start_offset;
int copied;
const unsigned char *src;
src = source;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
set_errno_and_return_minus_one( EIO );
/*
* Error check arguments
*/
assert( source );
if ( !source )
set_errno_and_return_minus_one( EINVAL );
/*
* If there is nothing to write, then quick exit.
*/
my_length = length;
if ( !my_length )
set_errno_and_return_minus_one( EINVAL );
/*
* If the last byte we are supposed to write is past the end of this
* in memory file, then extend the length.
*/
last_byte = start + length;
if ( last_byte > the_jnode->info.file.size ) {
status = IMFS_memfile_extend( the_jnode, last_byte );
if ( status )
set_errno_and_return_minus_one( ENOSPC );
}
copied = 0;
/*
* Three phases to the write:
* + possibly the last part of one block
* + all of zero of more blocks
* + possibly the first part of one block
*/
/*
* Phase 1: possibly the last part of one block
*/
start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK;
block = start / IMFS_MEMFILE_BYTES_PER_BLOCK;
if ( start_offset ) {
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset;
if ( to_copy > my_length )
to_copy = my_length;
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
#if 0
printf( "write %d at %d in %d: %*s\n", to_copy, start_offset, block, to_copy, src );
#endif
memcpy( &(*block_ptr)[ start_offset ], src, to_copy );
src += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 2: all of zero of more blocks
*/
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK;
while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
#if 0
printf( "write %d in %d: %*s\n", to_copy, block, to_copy, src );
#endif
memcpy( &(*block_ptr)[ 0 ], src, to_copy );
src += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 3: possibly the first part of one block
*/
assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK );
to_copy = my_length;
if ( my_length ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
#if 0
printf( "write %d in %d: %*s\n", to_copy, block, to_copy, src );
#endif
memcpy( &(*block_ptr)[ 0 ], src, my_length );
my_length = 0;
copied += to_copy;
}
IMFS_atime_mtime_update( the_jnode );
return copied;
}
/*
* IMFS_memfile_get_block_pointer
*
* This routine looks up the block pointer associated with the given block
* number. If that block has not been allocated and "malloc_it" is
* TRUE, then the block is allocated. Otherwise, it is an error.
*/
#if 0
block_p *IMFS_memfile_get_block_pointer_DEBUG(
IMFS_jnode_t *the_jnode,
unsigned int block,
int malloc_it
);
block_p *IMFS_memfile_get_block_pointer(
IMFS_jnode_t *the_jnode,
unsigned int block,
int malloc_it
)
{
block_p *p;
p = IMFS_memfile_get_block_pointer_DEBUG( the_jnode, block, malloc_it );
printf( "(%d -> %p) ", block, p );
return p;
}
block_p *IMFS_memfile_get_block_pointer_DEBUG(
#else
block_p *IMFS_memfile_get_block_pointer(
#endif
IMFS_jnode_t *the_jnode,
unsigned int block,
int malloc_it
)
{
unsigned int my_block;
IMFS_memfile_t *info;
unsigned int singly;
unsigned int doubly;
unsigned int triply;
block_p *p;
block_p *p1;
block_p *p2;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
return NULL;
assert( the_jnode->type == IMFS_MEMORY_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE )
return NULL;
info = &the_jnode->info.file;
my_block = block;
/*
* Is the block number in the simple indirect portion?
*/
if ( my_block <= LAST_INDIRECT ) {
#if 0
printf( "(s %d) ", block );
fflush(stdout);
#endif
p = info->indirect;
if ( malloc_it ) {
if ( !p ) {
p = memfile_alloc_block();
if ( !p )
return 0;
info->indirect = p;
}
return &info->indirect[ my_block ];
}
if ( !p )
return 0;
return &info->indirect[ my_block ];
}
/*
* Is the block number in the doubly indirect portion?
*/
if ( my_block <= LAST_DOUBLY_INDIRECT ) {
#if 0
printf( "(d %d) ", block );
fflush(stdout);
#endif
my_block -= FIRST_DOUBLY_INDIRECT;
singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS;
doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS;
p = info->doubly_indirect;
if ( malloc_it ) {
if ( !p ) {
p = memfile_alloc_block();
if ( !p )
return 0;
info->doubly_indirect = p;
}
p1 = (block_p *)p[ doubly ];
if ( !p1 ) {
p1 = memfile_alloc_block();
if ( !p1 )
return 0;
p[ doubly ] = (block_p) p1;
}
return (block_p *)&p1[ singly ];
}
if ( !p )
return 0;
p = (block_p *)p[ doubly ];
if ( !p )
return 0;
#if 0
printf( "(d %d %d %d %d %p %p) ", block, my_block, doubly,
singly, p, &p[singly] );
fflush(stdout);
#endif
return (block_p *)&p[ singly ];
}
#if 0
printf( "(t %d) ", block );
fflush(stdout);
#endif
/*
* Is the block number in the triply indirect portion?
*/
if ( my_block <= LAST_TRIPLY_INDIRECT ) {
my_block -= FIRST_TRIPLY_INDIRECT;
singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS;
doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS;
triply = doubly / IMFS_MEMFILE_BLOCK_SLOTS;
doubly %= IMFS_MEMFILE_BLOCK_SLOTS;
p = info->triply_indirect;
if ( malloc_it ) {
if ( !p ) {
p = memfile_alloc_block();
if ( !p )
return 0;
info->triply_indirect = p;
}
p1 = (block_p *) p[ triply ];
if ( !p1 ) {
p1 = memfile_alloc_block();
if ( !p1 )
return 0;
p[ triply ] = (block_p) p1;
}
p2 = (block_p *)p1[ doubly ];
if ( !p2 ) {
p2 = memfile_alloc_block();
if ( !p2 )
return 0;
p1[ doubly ] = (block_p) p2;
}
return (block_p *)&p2[ singly ];
}
if ( !p )
return 0;
#if 0
printf( "(t %d %d %d %d %d) ", block, my_block, triply, doubly, singly );
fflush(stdout);
#endif
p1 = (block_p *) p[ triply ];
if ( !p1 )
return 0;
p2 = (block_p *)p1[ doubly ];
if ( !p )
return 0;
return (block_p *)&p2[ singly ];
}
/*
* This means the requested block number is out of range.
*/
return 0;
}
/*
* memfile_alloc_block
*
* Allocate a block for an in-memory file.
*/
int memfile_blocks_allocated = 0;
void *memfile_alloc_block(void)
{
void *memory;
memory = (void *)calloc(1, IMFS_MEMFILE_BYTES_PER_BLOCK);
if ( memory )
memfile_blocks_allocated++;
return memory;
}
/*
* memfile_free_block
*
* Free a block from an in-memory file.
*/
void memfile_free_block(
void *memory
)
{
#if 0
printf( "(d %p) ", memory );
fflush(stdout);
#endif
free(memory);
memfile_blocks_allocated--;
}
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