[07a3253d] | 1 | /* |
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| 2 | * IMFS Device Node Handlers |
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| 3 | * |
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| 4 | * This file contains the set of handlers used to process operations on |
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| 5 | * IMFS memory file nodes. The memory files are created in memory using |
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| 6 | * malloc'ed memory. Thus any data stored in one of these files is lost |
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| 7 | * at system shutdown unless special arrangements to copy the data to |
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| 8 | * some type of non-volailte storage are made by the application. |
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| 9 | * |
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| 10 | * COPYRIGHT (c) 1989-1998. |
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| 11 | * On-Line Applications Research Corporation (OAR). |
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| 12 | * Copyright assigned to U.S. Government, 1994. |
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| 13 | * |
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| 14 | * The license and distribution terms for this file may be |
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| 15 | * found in the file LICENSE in this distribution or at |
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| 16 | * http://www.OARcorp.com/rtems/license.html. |
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| 17 | * |
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| 18 | * $Id$ |
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| 19 | */ |
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| 20 | |
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| 21 | #include <stdlib.h> |
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| 22 | #include <assert.h> |
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| 23 | #include <errno.h> |
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| 24 | |
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| 25 | #include <rtems.h> |
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| 26 | #include <rtems/libio.h> |
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| 27 | #include "imfs.h" |
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| 28 | #include "libio_.h" |
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| 29 | |
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| 30 | #define MEMFILE_STATIC |
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| 31 | |
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| 32 | /* |
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| 33 | * Prototypes of private routines |
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| 34 | */ |
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| 35 | |
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| 36 | MEMFILE_STATIC int IMFS_memfile_extend( |
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| 37 | IMFS_jnode_t *the_jnode, |
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| 38 | off_t new_length |
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| 39 | ); |
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| 40 | |
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| 41 | MEMFILE_STATIC int IMFS_memfile_addblock( |
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| 42 | IMFS_jnode_t *the_jnode, |
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| 43 | unsigned int block |
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| 44 | ); |
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| 45 | |
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| 46 | MEMFILE_STATIC int IMFS_memfile_remove_block( |
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| 47 | IMFS_jnode_t *the_jnode, |
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| 48 | unsigned int block |
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| 49 | ); |
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| 50 | |
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| 51 | MEMFILE_STATIC block_p *IMFS_memfile_get_block_pointer( |
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| 52 | IMFS_jnode_t *the_jnode, |
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| 53 | unsigned int block, |
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| 54 | int malloc_it |
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| 55 | ); |
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| 56 | |
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| 57 | MEMFILE_STATIC int IMFS_memfile_read( |
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| 58 | IMFS_jnode_t *the_jnode, |
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| 59 | off_t start, |
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| 60 | unsigned char *destination, |
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| 61 | unsigned int length |
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| 62 | ); |
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| 63 | |
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| 64 | MEMFILE_STATIC int IMFS_memfile_write( |
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| 65 | IMFS_jnode_t *the_jnode, |
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| 66 | off_t start, |
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| 67 | const unsigned char *source, |
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| 68 | unsigned int length |
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| 69 | ); |
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| 70 | |
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| 71 | void *memfile_alloc_block(void); |
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| 72 | |
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| 73 | void memfile_free_block( |
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| 74 | void *memory |
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| 75 | ); |
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| 76 | |
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| 77 | /* |
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| 78 | * memfile_open |
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| 79 | * |
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| 80 | * This routine processes the open() system call. Note that there is |
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| 81 | * nothing special to be done at open() time. |
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| 82 | */ |
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| 83 | |
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| 84 | int memfile_open( |
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| 85 | rtems_libio_t *iop, |
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| 86 | const char *pathname, |
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| 87 | unsigned32 flag, |
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| 88 | unsigned32 mode |
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| 89 | ) |
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| 90 | { |
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| 91 | IMFS_jnode_t *the_jnode; |
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| 92 | |
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| 93 | the_jnode = iop->file_info; |
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| 94 | |
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| 95 | return 0; |
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| 96 | } |
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| 97 | |
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| 98 | /* |
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| 99 | * memfile_close |
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| 100 | * |
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| 101 | * This routine processes the close() system call. Note that there is |
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| 102 | * nothing to flush or memory to free at this point. |
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| 103 | */ |
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| 104 | |
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| 105 | int memfile_close( |
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| 106 | rtems_libio_t *iop |
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| 107 | ) |
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| 108 | { |
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| 109 | IMFS_jnode_t *the_jnode; |
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| 110 | |
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| 111 | the_jnode = iop->file_info; |
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| 112 | |
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| 113 | return 0; |
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| 114 | } |
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| 115 | |
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| 116 | /* |
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| 117 | * memfile_read |
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| 118 | * |
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| 119 | * This routine processes the read() system call. |
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| 120 | */ |
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| 121 | |
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| 122 | int memfile_read( |
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| 123 | rtems_libio_t *iop, |
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| 124 | void *buffer, |
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| 125 | unsigned32 count |
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| 126 | ) |
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| 127 | { |
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| 128 | IMFS_jnode_t *the_jnode; |
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| 129 | |
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| 130 | the_jnode = iop->file_info; |
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| 131 | |
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| 132 | return IMFS_memfile_read( the_jnode, iop->offset, buffer, count ); |
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| 133 | } |
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| 134 | |
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| 135 | /* |
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| 136 | * memfile_write |
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| 137 | * |
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| 138 | * This routine processes the write() system call. |
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| 139 | */ |
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| 140 | |
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| 141 | int memfile_write( |
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| 142 | rtems_libio_t *iop, |
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| 143 | const void *buffer, |
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| 144 | unsigned32 count |
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| 145 | ) |
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| 146 | { |
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| 147 | IMFS_jnode_t *the_jnode; |
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[efb1b830] | 148 | int status; |
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[07a3253d] | 149 | |
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| 150 | the_jnode = iop->file_info; |
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| 151 | |
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[efb1b830] | 152 | status = IMFS_memfile_write( the_jnode, iop->offset, buffer, count ); |
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| 153 | iop->size = the_jnode->info.file.size; |
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| 154 | |
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| 155 | return status; |
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[07a3253d] | 156 | } |
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| 157 | |
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| 158 | /* |
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| 159 | * memfile_ioctl |
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| 160 | * |
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| 161 | * This routine processes the ioctl() system call. |
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| 162 | * |
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| 163 | * NOTE: No ioctl()'s are supported for in-memory files. |
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| 164 | */ |
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| 165 | |
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| 166 | int memfile_ioctl( |
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| 167 | rtems_libio_t *iop, |
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| 168 | unsigned32 command, |
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| 169 | void *buffer |
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| 170 | ) |
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| 171 | { |
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| 172 | IMFS_jnode_t *the_jnode; |
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| 173 | |
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| 174 | the_jnode = iop->file_info; |
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| 175 | |
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| 176 | return 0; |
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| 177 | } |
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| 178 | |
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| 179 | /* |
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| 180 | * memfile_lseek |
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| 181 | * |
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| 182 | * This routine processes the lseek() system call. |
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| 183 | */ |
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| 184 | |
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| 185 | int memfile_lseek( |
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| 186 | rtems_libio_t *iop, |
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| 187 | off_t offset, |
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| 188 | int whence |
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| 189 | ) |
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| 190 | { |
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| 191 | IMFS_jnode_t *the_jnode; |
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| 192 | |
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| 193 | the_jnode = iop->file_info; |
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| 194 | |
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| 195 | if (IMFS_memfile_extend( the_jnode, iop->offset )) |
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| 196 | set_errno_and_return_minus_one( ENOSPC ); |
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| 197 | |
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[efb1b830] | 198 | iop->size = the_jnode->info.file.size; |
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| 199 | return iop->offset; |
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[07a3253d] | 200 | } |
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| 201 | |
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| 202 | /* |
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| 203 | * memfile_stat |
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| 204 | * |
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| 205 | * This IMFS_stat() can be used. |
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| 206 | */ |
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| 207 | |
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| 208 | /* |
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| 209 | * memfile_ftruncate |
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| 210 | * |
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| 211 | * This routine processes the ftruncate() system call. |
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| 212 | */ |
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| 213 | |
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| 214 | int memfile_ftruncate( |
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| 215 | rtems_libio_t *iop, |
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| 216 | off_t length |
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| 217 | ) |
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| 218 | { |
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| 219 | IMFS_jnode_t *the_jnode; |
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| 220 | |
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| 221 | the_jnode = iop->file_info; |
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| 222 | |
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| 223 | /* |
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| 224 | * POSIX 1003.1b does not specify what happens if you truncate a file |
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| 225 | * and the new length is greater than the current size. We treat this |
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| 226 | * as an extend operation. |
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| 227 | */ |
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| 228 | |
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| 229 | if ( length > the_jnode->info.file.size ) |
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| 230 | return IMFS_memfile_extend( the_jnode, length ); |
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| 231 | |
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| 232 | /* |
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| 233 | * The in-memory files do not currently reclaim memory until the file is |
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| 234 | * deleted. So we leave the previously allocated blocks in place for |
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| 235 | * future use and just set the length. |
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| 236 | */ |
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| 237 | |
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| 238 | the_jnode->info.file.size = length; |
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[efb1b830] | 239 | iop->size = the_jnode->info.file.size; |
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[07a3253d] | 240 | |
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| 241 | IMFS_update_atime( the_jnode ); |
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| 242 | |
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| 243 | return 0; |
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| 244 | } |
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| 245 | |
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| 246 | /* |
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| 247 | * IMFS_memfile_extend |
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| 248 | * |
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| 249 | * This routine insures that the in-memory file is of the length |
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| 250 | * specified. If necessary, it will allocate memory blocks to |
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| 251 | * extend the file. |
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| 252 | */ |
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| 253 | |
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| 254 | MEMFILE_STATIC int IMFS_memfile_extend( |
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| 255 | IMFS_jnode_t *the_jnode, |
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| 256 | off_t new_length |
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| 257 | ) |
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| 258 | { |
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| 259 | unsigned int block; |
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| 260 | unsigned int new_blocks; |
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| 261 | unsigned int old_blocks; |
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| 262 | |
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| 263 | /* |
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| 264 | * Perform internal consistency checks |
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| 265 | */ |
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| 266 | |
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| 267 | assert( the_jnode ); |
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| 268 | if ( !the_jnode ) |
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| 269 | set_errno_and_return_minus_one( EIO ); |
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| 270 | |
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| 271 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
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| 272 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
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| 273 | set_errno_and_return_minus_one( EIO ); |
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| 274 | |
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| 275 | if ( new_length >= IMFS_MEMFILE_MAXIMUM_SIZE ) |
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| 276 | set_errno_and_return_minus_one( EINVAL ); |
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| 277 | |
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| 278 | if ( new_length <= the_jnode->info.file.size ) |
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| 279 | return 0; |
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| 280 | |
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| 281 | /* |
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| 282 | * Calculate the number of range of blocks to allocate |
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| 283 | */ |
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| 284 | |
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| 285 | new_blocks = new_length / IMFS_MEMFILE_BYTES_PER_BLOCK; |
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| 286 | old_blocks = the_jnode->info.file.size / IMFS_MEMFILE_BYTES_PER_BLOCK; |
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| 287 | |
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| 288 | /* |
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| 289 | * Now allocate each of those blocks. |
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| 290 | */ |
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| 291 | |
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| 292 | for ( block=old_blocks ; block<=new_blocks ; block++ ) { |
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| 293 | if ( IMFS_memfile_addblock( the_jnode, block ) ) { |
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| 294 | for ( ; block>=old_blocks ; block-- ) { |
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| 295 | IMFS_memfile_remove_block( the_jnode, block ); |
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| 296 | } |
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| 297 | set_errno_and_return_minus_one( ENOSPC ); |
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| 298 | } |
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| 299 | } |
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| 300 | |
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| 301 | /* |
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| 302 | * Set the new length of the file. |
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| 303 | */ |
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| 304 | |
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| 305 | the_jnode->info.file.size = new_length; |
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| 306 | return 0; |
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| 307 | } |
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| 308 | |
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| 309 | /* |
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| 310 | * IMFS_memfile_addblock |
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| 311 | * |
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| 312 | * This routine adds a single block to the specified in-memory file. |
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| 313 | */ |
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| 314 | |
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| 315 | MEMFILE_STATIC int IMFS_memfile_addblock( |
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| 316 | IMFS_jnode_t *the_jnode, |
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| 317 | unsigned int block |
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| 318 | ) |
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| 319 | { |
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| 320 | block_p memory; |
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| 321 | block_p *block_entry_ptr; |
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| 322 | |
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| 323 | assert( the_jnode ); |
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| 324 | if ( !the_jnode ) |
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| 325 | set_errno_and_return_minus_one( EIO ); |
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| 326 | |
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| 327 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
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| 328 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
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| 329 | set_errno_and_return_minus_one( EIO ); |
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| 330 | |
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| 331 | block_entry_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 1 ); |
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| 332 | if ( *block_entry_ptr ) |
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| 333 | return 0; |
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| 334 | |
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| 335 | #if 0 |
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| 336 | printf( "%d %p", block, block_entry_ptr ); |
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| 337 | fflush(stdout); |
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| 338 | #endif |
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| 339 | |
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| 340 | memory = memfile_alloc_block(); |
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| 341 | assert( memory ); |
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| 342 | if ( !memory ) |
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| 343 | return 1; |
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| 344 | *block_entry_ptr = memory; |
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| 345 | |
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| 346 | return 0; |
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| 347 | } |
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| 348 | |
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| 349 | /* |
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| 350 | * IMFS_memfile_remove_block |
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| 351 | * |
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| 352 | * This routine removes the specified block from the in-memory file. |
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| 353 | * |
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| 354 | * NOTE: This is a support routine and is called only to remove |
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| 355 | * the last block or set of blocks in a file. Removing a |
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| 356 | * block from the middle of a file would be exceptionally |
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| 357 | * dangerous and the results unpredictable. |
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| 358 | */ |
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| 359 | |
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| 360 | MEMFILE_STATIC int IMFS_memfile_remove_block( |
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| 361 | IMFS_jnode_t *the_jnode, |
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| 362 | unsigned int block |
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| 363 | ) |
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| 364 | { |
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| 365 | block_p *block_entry_ptr; |
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| 366 | block_p ptr; |
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| 367 | |
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| 368 | block_entry_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
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| 369 | ptr = *block_entry_ptr; |
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| 370 | *block_entry_ptr = 0; |
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| 371 | |
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| 372 | memfile_free_block( ptr ); |
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| 373 | |
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| 374 | return 1; |
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| 375 | } |
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| 376 | |
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| 377 | /* |
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| 378 | * memfile_free_blocks_in_table |
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| 379 | * |
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| 380 | * This is a support routine for IMFS_memfile_remove. It frees all the |
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| 381 | * blocks in one of the indirection tables. |
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| 382 | */ |
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| 383 | |
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| 384 | void memfile_free_blocks_in_table( |
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| 385 | block_p **block_table, |
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| 386 | int entries |
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| 387 | ) |
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| 388 | { |
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| 389 | int i; |
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| 390 | block_p *b; |
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| 391 | |
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| 392 | /* |
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| 393 | * Perform internal consistency checks |
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| 394 | */ |
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| 395 | |
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| 396 | assert( block_table ); |
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| 397 | if ( !block_table ) |
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| 398 | return; |
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| 399 | |
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| 400 | /* |
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| 401 | * Now go through all the slots in the table and free the memory. |
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| 402 | */ |
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| 403 | |
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| 404 | b = *block_table; |
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| 405 | |
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| 406 | for ( i=0 ; i<entries ; i++ ) { |
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| 407 | if ( b[i] ) { |
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| 408 | memfile_free_block( b[i] ); |
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| 409 | b[i] = 0; |
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| 410 | } |
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| 411 | } |
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| 412 | |
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| 413 | /* |
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| 414 | * Now that all the blocks in the block table are free, we can |
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| 415 | * free the block table itself. |
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| 416 | */ |
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| 417 | |
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| 418 | memfile_free_block( *block_table ); |
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| 419 | *block_table = 0; |
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| 420 | } |
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| 421 | |
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| 422 | /* |
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| 423 | * IMFS_memfile_remove |
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| 424 | * |
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| 425 | * This routine frees all memory associated with an in memory file. |
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| 426 | * |
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| 427 | * NOTE: This is an exceptionally conservative implementation. |
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| 428 | * It will check EVERY pointer which is non-NULL and insure |
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| 429 | * any child non-NULL pointers are freed. Optimistically, all that |
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| 430 | * is necessary is to scan until a NULL pointer is found. There |
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| 431 | * should be no allocated data past that point. |
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| 432 | * |
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| 433 | * In experimentation on the powerpc simulator, it was noted |
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| 434 | * that using blocks which held 128 slots versus 16 slots made |
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| 435 | * a significant difference in the performance of this routine. |
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| 436 | * |
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| 437 | * Regardless until the IMFS implementation is proven, it |
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| 438 | * is better to stick to simple, easy to understand algorithms. |
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| 439 | */ |
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| 440 | |
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| 441 | int IMFS_memfile_remove( |
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| 442 | IMFS_jnode_t *the_jnode |
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| 443 | ) |
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| 444 | { |
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| 445 | IMFS_memfile_t *info; |
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| 446 | int i; |
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| 447 | int j; |
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| 448 | unsigned int to_free; |
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| 449 | block_p *p; |
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| 450 | |
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| 451 | /* |
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| 452 | * Perform internal consistency checks |
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| 453 | */ |
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| 454 | |
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| 455 | assert( the_jnode ); |
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| 456 | if ( !the_jnode ) |
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| 457 | set_errno_and_return_minus_one( EIO ); |
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| 458 | |
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| 459 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
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| 460 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
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| 461 | set_errno_and_return_minus_one( EIO ); |
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| 462 | |
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| 463 | /* |
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| 464 | * Eventually this could be set smarter at each call to |
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| 465 | * memfile_free_blocks_in_table to greatly speed this up. |
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| 466 | */ |
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| 467 | |
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| 468 | to_free = IMFS_MEMFILE_BLOCK_SLOTS; |
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| 469 | |
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| 470 | /* |
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| 471 | * Now start freeing blocks in this order: |
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| 472 | * + indirect |
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| 473 | * + doubly indirect |
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| 474 | * + triply indirect |
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| 475 | */ |
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| 476 | |
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| 477 | info = &the_jnode->info.file; |
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| 478 | |
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| 479 | if ( info->indirect ) { |
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| 480 | memfile_free_blocks_in_table( &info->indirect, to_free ); |
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| 481 | } |
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| 482 | |
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| 483 | if ( info->doubly_indirect ) { |
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| 484 | |
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| 485 | for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) { |
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| 486 | if ( info->doubly_indirect[i] ) { |
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| 487 | memfile_free_blocks_in_table( |
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| 488 | (block_p **)&info->doubly_indirect[i], to_free ); |
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| 489 | } |
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| 490 | } |
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| 491 | memfile_free_blocks_in_table( &info->doubly_indirect, to_free ); |
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| 492 | |
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| 493 | } |
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| 494 | |
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| 495 | if ( info->triply_indirect ) { |
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| 496 | for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) { |
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| 497 | p = (block_p *) info->triply_indirect[i]; |
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| 498 | for ( j=0 ; j<IMFS_MEMFILE_BLOCK_SLOTS ; j++ ) { |
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| 499 | if ( p[j] ) { |
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| 500 | memfile_free_blocks_in_table( (block_p **)&p[j], to_free); |
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| 501 | } |
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| 502 | } |
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| 503 | memfile_free_blocks_in_table( |
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| 504 | (block_p **)&info->triply_indirect[i], to_free ); |
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| 505 | } |
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| 506 | memfile_free_blocks_in_table( |
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| 507 | (block_p **)&info->triply_indirect, to_free ); |
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| 508 | } |
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| 509 | |
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| 510 | return 0; |
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| 511 | } |
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| 512 | |
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| 513 | /* |
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| 514 | * IMFS_memfile_read |
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| 515 | * |
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| 516 | * This routine read from memory file pointed to by the_jnode into |
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| 517 | * the specified data buffer specified by destination. The file |
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| 518 | * is NOT extended. An offset greater than the length of the file |
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| 519 | * is considered an error. Read from an offset for more bytes than |
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| 520 | * are between the offset and the end of the file will result in |
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| 521 | * reading the data between offset and the end of the file (truncated |
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| 522 | * read). |
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| 523 | */ |
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| 524 | |
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| 525 | MEMFILE_STATIC int IMFS_memfile_read( |
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| 526 | IMFS_jnode_t *the_jnode, |
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| 527 | off_t start, |
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| 528 | unsigned char *destination, |
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| 529 | unsigned int length |
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| 530 | ) |
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| 531 | { |
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| 532 | block_p *block_ptr; |
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| 533 | unsigned int block; |
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| 534 | unsigned int my_length; |
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| 535 | unsigned int to_copy = 0; |
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| 536 | unsigned int last_byte; |
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| 537 | unsigned int copied; |
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| 538 | unsigned int start_offset; |
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| 539 | unsigned char *dest; |
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| 540 | |
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| 541 | dest = destination; |
---|
| 542 | |
---|
| 543 | /* |
---|
| 544 | * Perform internal consistency checks |
---|
| 545 | */ |
---|
| 546 | |
---|
| 547 | assert( the_jnode ); |
---|
| 548 | if ( !the_jnode ) |
---|
| 549 | set_errno_and_return_minus_one( EIO ); |
---|
| 550 | |
---|
| 551 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
---|
| 552 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
---|
| 553 | set_errno_and_return_minus_one( EIO ); |
---|
| 554 | |
---|
| 555 | /* |
---|
| 556 | * Error checks on arguments |
---|
| 557 | */ |
---|
| 558 | |
---|
| 559 | assert( dest ); |
---|
| 560 | if ( !dest ) |
---|
| 561 | set_errno_and_return_minus_one( EINVAL ); |
---|
| 562 | |
---|
| 563 | /* |
---|
| 564 | * If there is nothing to read, then quick exit. |
---|
| 565 | */ |
---|
| 566 | |
---|
| 567 | my_length = length; |
---|
| 568 | if ( !my_length ) |
---|
| 569 | set_errno_and_return_minus_one( EINVAL ); |
---|
| 570 | |
---|
| 571 | /* |
---|
| 572 | * If the last byte we are supposed to read is past the end of this |
---|
| 573 | * in memory file, then shorten the length to read. |
---|
| 574 | */ |
---|
| 575 | |
---|
| 576 | last_byte = start + length; |
---|
| 577 | if ( last_byte > the_jnode->info.file.size ) |
---|
| 578 | my_length = the_jnode->info.file.size - start; |
---|
| 579 | |
---|
| 580 | copied = 0; |
---|
| 581 | |
---|
| 582 | /* |
---|
| 583 | * Three phases to the read: |
---|
| 584 | * + possibly the last part of one block |
---|
| 585 | * + all of zero of more blocks |
---|
| 586 | * + possibly the first part of one block |
---|
| 587 | */ |
---|
| 588 | |
---|
| 589 | /* |
---|
| 590 | * Phase 1: possibly the last part of one block |
---|
| 591 | */ |
---|
| 592 | |
---|
| 593 | start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 594 | block = start / IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 595 | if ( start_offset ) { |
---|
| 596 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset; |
---|
| 597 | if ( to_copy > my_length ) |
---|
| 598 | to_copy = my_length; |
---|
| 599 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 600 | assert( block_ptr ); |
---|
| 601 | if ( !block_ptr ) |
---|
| 602 | return copied; |
---|
| 603 | memcpy( dest, &(*block_ptr)[ start_offset ], to_copy ); |
---|
| 604 | dest += to_copy; |
---|
| 605 | block++; |
---|
| 606 | my_length -= to_copy; |
---|
| 607 | copied += to_copy; |
---|
| 608 | } |
---|
| 609 | |
---|
| 610 | /* |
---|
| 611 | * Phase 2: all of zero of more blocks |
---|
| 612 | */ |
---|
| 613 | |
---|
| 614 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 615 | while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) { |
---|
| 616 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 617 | assert( block_ptr ); |
---|
| 618 | if ( !block_ptr ) |
---|
| 619 | return copied; |
---|
| 620 | memcpy( dest, &(*block_ptr)[ 0 ], to_copy ); |
---|
| 621 | dest += to_copy; |
---|
| 622 | block++; |
---|
| 623 | my_length -= to_copy; |
---|
| 624 | copied += to_copy; |
---|
| 625 | } |
---|
| 626 | |
---|
| 627 | /* |
---|
| 628 | * Phase 3: possibly the first part of one block |
---|
| 629 | */ |
---|
| 630 | |
---|
| 631 | assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK ); |
---|
| 632 | |
---|
| 633 | if ( my_length ) { |
---|
| 634 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 635 | assert( block_ptr ); |
---|
| 636 | if ( !block_ptr ) |
---|
| 637 | return copied; |
---|
| 638 | memcpy( dest, &(*block_ptr)[ 0 ], my_length ); |
---|
| 639 | copied += my_length; |
---|
| 640 | } |
---|
| 641 | |
---|
| 642 | IMFS_update_atime( the_jnode ); |
---|
| 643 | |
---|
| 644 | return copied; |
---|
| 645 | } |
---|
| 646 | |
---|
| 647 | /* |
---|
| 648 | * IMFS_memfile_write |
---|
| 649 | * |
---|
| 650 | * This routine writes the specified data buffer into the in memory |
---|
| 651 | * file pointed to by the_jnode. The file is extended as needed. |
---|
| 652 | */ |
---|
| 653 | |
---|
| 654 | MEMFILE_STATIC int IMFS_memfile_write( |
---|
| 655 | IMFS_jnode_t *the_jnode, |
---|
| 656 | off_t start, |
---|
| 657 | const unsigned char *source, |
---|
| 658 | unsigned int length |
---|
| 659 | ) |
---|
| 660 | { |
---|
| 661 | block_p *block_ptr; |
---|
| 662 | unsigned int block; |
---|
| 663 | int status; |
---|
| 664 | unsigned int my_length; |
---|
| 665 | unsigned int to_copy = 0; |
---|
| 666 | unsigned int last_byte; |
---|
| 667 | unsigned int start_offset; |
---|
| 668 | int copied; |
---|
| 669 | const unsigned char *src; |
---|
| 670 | |
---|
| 671 | src = source; |
---|
| 672 | |
---|
| 673 | /* |
---|
| 674 | * Perform internal consistency checks |
---|
| 675 | */ |
---|
| 676 | |
---|
| 677 | assert( the_jnode ); |
---|
| 678 | if ( !the_jnode ) |
---|
| 679 | set_errno_and_return_minus_one( EIO ); |
---|
| 680 | |
---|
| 681 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
---|
| 682 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
---|
| 683 | set_errno_and_return_minus_one( EIO ); |
---|
| 684 | |
---|
| 685 | /* |
---|
| 686 | * Error check arguments |
---|
| 687 | */ |
---|
| 688 | |
---|
| 689 | assert( source ); |
---|
| 690 | if ( !source ) |
---|
| 691 | set_errno_and_return_minus_one( EINVAL ); |
---|
| 692 | |
---|
| 693 | |
---|
| 694 | /* |
---|
| 695 | * If there is nothing to write, then quick exit. |
---|
| 696 | */ |
---|
| 697 | |
---|
| 698 | my_length = length; |
---|
| 699 | if ( !my_length ) |
---|
| 700 | set_errno_and_return_minus_one( EINVAL ); |
---|
| 701 | |
---|
| 702 | /* |
---|
| 703 | * If the last byte we are supposed to write is past the end of this |
---|
| 704 | * in memory file, then extend the length. |
---|
| 705 | */ |
---|
| 706 | |
---|
| 707 | last_byte = start + length; |
---|
| 708 | if ( last_byte > the_jnode->info.file.size ) { |
---|
| 709 | status = IMFS_memfile_extend( the_jnode, last_byte ); |
---|
| 710 | if ( status ) |
---|
| 711 | set_errno_and_return_minus_one( ENOSPC ); |
---|
| 712 | } |
---|
| 713 | |
---|
| 714 | copied = 0; |
---|
| 715 | |
---|
| 716 | /* |
---|
| 717 | * Three phases to the write: |
---|
| 718 | * + possibly the last part of one block |
---|
| 719 | * + all of zero of more blocks |
---|
| 720 | * + possibly the first part of one block |
---|
| 721 | */ |
---|
| 722 | |
---|
| 723 | /* |
---|
| 724 | * Phase 1: possibly the last part of one block |
---|
| 725 | */ |
---|
| 726 | |
---|
| 727 | start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 728 | block = start / IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 729 | if ( start_offset ) { |
---|
| 730 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset; |
---|
| 731 | if ( to_copy > my_length ) |
---|
| 732 | to_copy = my_length; |
---|
| 733 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 734 | assert( block_ptr ); |
---|
| 735 | if ( !block_ptr ) |
---|
| 736 | return copied; |
---|
| 737 | memcpy( &(*block_ptr)[ start_offset ], src, to_copy ); |
---|
| 738 | src += to_copy; |
---|
| 739 | block++; |
---|
| 740 | my_length -= to_copy; |
---|
| 741 | copied += to_copy; |
---|
| 742 | } |
---|
| 743 | |
---|
| 744 | /* |
---|
| 745 | * Phase 2: all of zero of more blocks |
---|
| 746 | */ |
---|
| 747 | |
---|
| 748 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
| 749 | while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) { |
---|
| 750 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 751 | assert( block_ptr ); |
---|
| 752 | if ( !block_ptr ) |
---|
| 753 | return copied; |
---|
| 754 | memcpy( &(*block_ptr)[ 0 ], src, to_copy ); |
---|
| 755 | src += to_copy; |
---|
| 756 | block++; |
---|
| 757 | my_length -= to_copy; |
---|
| 758 | copied += to_copy; |
---|
| 759 | } |
---|
| 760 | |
---|
| 761 | /* |
---|
| 762 | * Phase 3: possibly the first part of one block |
---|
| 763 | */ |
---|
| 764 | |
---|
| 765 | assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK ); |
---|
| 766 | |
---|
| 767 | to_copy = my_length; |
---|
| 768 | if ( my_length ) { |
---|
| 769 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
| 770 | assert( block_ptr ); |
---|
| 771 | if ( !block_ptr ) |
---|
| 772 | return copied; |
---|
| 773 | memcpy( &(*block_ptr)[ 0 ], src, my_length ); |
---|
| 774 | my_length = 0; |
---|
| 775 | copied += to_copy; |
---|
| 776 | } |
---|
| 777 | |
---|
| 778 | IMFS_atime_mtime_update( the_jnode ); |
---|
| 779 | |
---|
| 780 | return copied; |
---|
| 781 | } |
---|
| 782 | |
---|
| 783 | /* |
---|
| 784 | * IMFS_memfile_get_block_pointer |
---|
| 785 | * |
---|
| 786 | * This routine looks up the block pointer associated with the given block |
---|
| 787 | * number. If that block has not been allocated and "malloc_it" is |
---|
| 788 | * TRUE, then the block is allocated. Otherwise, it is an error. |
---|
| 789 | */ |
---|
| 790 | |
---|
| 791 | block_p *IMFS_memfile_get_block_pointer( |
---|
| 792 | IMFS_jnode_t *the_jnode, |
---|
| 793 | unsigned int block, |
---|
| 794 | int malloc_it |
---|
| 795 | ) |
---|
| 796 | { |
---|
| 797 | unsigned int my_block; |
---|
| 798 | IMFS_memfile_t *info; |
---|
| 799 | unsigned int singly; |
---|
| 800 | unsigned int doubly; |
---|
| 801 | unsigned int triply; |
---|
| 802 | block_p *p; |
---|
| 803 | block_p *p1; |
---|
| 804 | block_p *p2; |
---|
| 805 | |
---|
| 806 | /* |
---|
| 807 | * Perform internal consistency checks |
---|
| 808 | */ |
---|
| 809 | |
---|
| 810 | assert( the_jnode ); |
---|
| 811 | if ( !the_jnode ) |
---|
| 812 | return NULL; |
---|
| 813 | |
---|
| 814 | assert( the_jnode->type == IMFS_MEMORY_FILE ); |
---|
| 815 | if ( the_jnode->type != IMFS_MEMORY_FILE ) |
---|
| 816 | return NULL; |
---|
| 817 | |
---|
| 818 | info = &the_jnode->info.file; |
---|
| 819 | |
---|
| 820 | my_block = block; |
---|
| 821 | |
---|
| 822 | /* |
---|
| 823 | * Is the block number in the simple indirect portion? |
---|
| 824 | */ |
---|
| 825 | |
---|
| 826 | if ( my_block <= LAST_INDIRECT ) { |
---|
| 827 | #if 0 |
---|
| 828 | printf( "(s %d) ", block ); |
---|
| 829 | fflush(stdout); |
---|
| 830 | #endif |
---|
| 831 | p = info->indirect; |
---|
| 832 | |
---|
| 833 | if ( malloc_it ) { |
---|
| 834 | |
---|
| 835 | if ( !p ) { |
---|
| 836 | p = memfile_alloc_block(); |
---|
| 837 | if ( !p ) |
---|
| 838 | return 0; |
---|
| 839 | info->indirect = p; |
---|
| 840 | } |
---|
| 841 | return &info->indirect[ my_block ]; |
---|
| 842 | } |
---|
| 843 | |
---|
| 844 | if ( !p ) |
---|
| 845 | return 0; |
---|
| 846 | |
---|
| 847 | return &info->indirect[ my_block ]; |
---|
| 848 | } |
---|
| 849 | |
---|
| 850 | /* |
---|
| 851 | * Is the block number in the doubly indirect portion? |
---|
| 852 | */ |
---|
| 853 | |
---|
| 854 | if ( my_block <= LAST_DOUBLY_INDIRECT ) { |
---|
| 855 | #if 0 |
---|
| 856 | printf( "(d %d) ", block ); |
---|
| 857 | fflush(stdout); |
---|
| 858 | #endif |
---|
| 859 | |
---|
| 860 | my_block -= FIRST_DOUBLY_INDIRECT; |
---|
| 861 | |
---|
| 862 | singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 863 | doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 864 | |
---|
| 865 | p = info->doubly_indirect; |
---|
| 866 | if ( malloc_it ) { |
---|
| 867 | |
---|
| 868 | if ( !p ) { |
---|
| 869 | p = memfile_alloc_block(); |
---|
| 870 | if ( !p ) |
---|
| 871 | return 0; |
---|
| 872 | info->doubly_indirect = p; |
---|
| 873 | } |
---|
| 874 | |
---|
| 875 | p1 = (block_p *)p[ doubly ]; |
---|
| 876 | if ( !p1 ) { |
---|
| 877 | p1 = memfile_alloc_block(); |
---|
| 878 | if ( !p1 ) |
---|
| 879 | return 0; |
---|
| 880 | p[ doubly ] = (block_p) p1; |
---|
| 881 | } |
---|
| 882 | |
---|
| 883 | return (block_p *)&p[ singly ]; |
---|
| 884 | } |
---|
| 885 | |
---|
| 886 | if ( !p ) |
---|
| 887 | return 0; |
---|
| 888 | |
---|
| 889 | p = (block_p *)p[ doubly ]; |
---|
| 890 | if ( !p ) |
---|
| 891 | return 0; |
---|
| 892 | |
---|
| 893 | #if 0 |
---|
| 894 | printf( "(d %d %d %d %d %p %p) ", block, my_block, doubly, |
---|
| 895 | singly, p, &p[singly] ); |
---|
| 896 | fflush(stdout); |
---|
| 897 | #endif |
---|
| 898 | return (block_p *)&p[ singly ]; |
---|
| 899 | } |
---|
| 900 | |
---|
| 901 | #if 0 |
---|
| 902 | printf( "(t %d) ", block ); |
---|
| 903 | fflush(stdout); |
---|
| 904 | #endif |
---|
| 905 | /* |
---|
| 906 | * Is the block number in the triply indirect portion? |
---|
| 907 | */ |
---|
| 908 | |
---|
| 909 | if ( my_block <= LAST_TRIPLY_INDIRECT ) { |
---|
| 910 | my_block -= FIRST_TRIPLY_INDIRECT; |
---|
| 911 | |
---|
| 912 | singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 913 | doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 914 | triply = doubly / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 915 | doubly %= IMFS_MEMFILE_BLOCK_SLOTS; |
---|
| 916 | |
---|
| 917 | p = info->triply_indirect; |
---|
| 918 | |
---|
| 919 | if ( malloc_it ) { |
---|
| 920 | if ( !p ) { |
---|
| 921 | p = memfile_alloc_block(); |
---|
| 922 | if ( !p ) |
---|
| 923 | return 0; |
---|
| 924 | info->triply_indirect = p; |
---|
| 925 | } |
---|
| 926 | |
---|
| 927 | p1 = (block_p *) p[ triply ]; |
---|
| 928 | if ( !p1 ) { |
---|
| 929 | p1 = memfile_alloc_block(); |
---|
| 930 | if ( !p1 ) |
---|
| 931 | return 0; |
---|
| 932 | p[ triply ] = (block_p) p1; |
---|
| 933 | } |
---|
| 934 | |
---|
| 935 | p2 = (block_p *)p1[ doubly ]; |
---|
| 936 | if ( !p2 ) { |
---|
| 937 | p2 = memfile_alloc_block(); |
---|
| 938 | if ( !p2 ) |
---|
| 939 | return 0; |
---|
| 940 | p1[ doubly ] = (block_p) p2; |
---|
| 941 | } |
---|
| 942 | return (block_p *)&p2[ singly ]; |
---|
| 943 | } |
---|
| 944 | |
---|
| 945 | if ( !p ) |
---|
| 946 | return 0; |
---|
| 947 | |
---|
| 948 | #if 0 |
---|
| 949 | printf( "(t %d %d %d %d %d) ", block, my_block, triply, doubly, singly ); |
---|
| 950 | fflush(stdout); |
---|
| 951 | #endif |
---|
| 952 | p1 = (block_p *) p[ triply ]; |
---|
| 953 | if ( !p1 ) |
---|
| 954 | return 0; |
---|
| 955 | |
---|
| 956 | p2 = (block_p *)p1[ doubly ]; |
---|
| 957 | if ( !p ) |
---|
| 958 | return 0; |
---|
| 959 | |
---|
| 960 | return (block_p *)&p2[ singly ]; |
---|
| 961 | } |
---|
| 962 | |
---|
| 963 | /* |
---|
| 964 | * This means the requested block number is out of range. |
---|
| 965 | */ |
---|
| 966 | |
---|
| 967 | return 0; |
---|
| 968 | } |
---|
| 969 | |
---|
| 970 | /* |
---|
| 971 | * memfile_alloc_block |
---|
| 972 | * |
---|
| 973 | * Allocate a block for an in-memory file. |
---|
| 974 | */ |
---|
| 975 | |
---|
| 976 | int memfile_blocks_allocated = 0; |
---|
| 977 | |
---|
| 978 | void *memfile_alloc_block(void) |
---|
| 979 | { |
---|
| 980 | void *memory; |
---|
| 981 | |
---|
| 982 | memory = (void *)calloc(1, IMFS_MEMFILE_BYTES_PER_BLOCK); |
---|
| 983 | if ( memory ) |
---|
| 984 | memfile_blocks_allocated++; |
---|
| 985 | |
---|
| 986 | return memory; |
---|
| 987 | } |
---|
| 988 | |
---|
| 989 | /* |
---|
| 990 | * memfile_free_blocK |
---|
| 991 | * |
---|
| 992 | * Free a block from an in-memory file. |
---|
| 993 | */ |
---|
| 994 | |
---|
| 995 | void memfile_free_block( |
---|
| 996 | void *memory |
---|
| 997 | ) |
---|
| 998 | { |
---|
| 999 | #if 0 |
---|
| 1000 | printf( "(d %p) ", memory ); |
---|
| 1001 | fflush(stdout); |
---|
| 1002 | #endif |
---|
| 1003 | free(memory); |
---|
| 1004 | memfile_blocks_allocated--; |
---|
| 1005 | } |
---|
| 1006 | |
---|