paul@90 | 1 | /* |
paul@90 | 2 | * Filesystem client functions. |
paul@90 | 3 | * |
paul@90 | 4 | * Copyright (C) 2018, 2019, 2020, 2021 Paul Boddie <paul@boddie.org.uk> |
paul@90 | 5 | * |
paul@90 | 6 | * This program is free software; you can redistribute it and/or |
paul@90 | 7 | * modify it under the terms of the GNU General Public License as |
paul@90 | 8 | * published by the Free Software Foundation; either version 2 of |
paul@90 | 9 | * the License, or (at your option) any later version. |
paul@90 | 10 | * |
paul@90 | 11 | * This program is distributed in the hope that it will be useful, |
paul@90 | 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
paul@90 | 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
paul@90 | 14 | * GNU General Public License for more details. |
paul@90 | 15 | * |
paul@90 | 16 | * You should have received a copy of the GNU General Public License |
paul@90 | 17 | * along with this program; if not, write to the Free Software |
paul@90 | 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, |
paul@90 | 19 | * Boston, MA 02110-1301, USA |
paul@90 | 20 | */ |
paul@90 | 21 | |
paul@90 | 22 | #include <l4/re/env.h> |
paul@90 | 23 | |
paul@90 | 24 | #include <stdio.h> |
paul@90 | 25 | #include <stdlib.h> |
paul@90 | 26 | |
paul@90 | 27 | #include "client.h" |
paul@90 | 28 | |
paul@90 | 29 | |
paul@90 | 30 | |
paul@90 | 31 | /* Default size of pipe regions. */ |
paul@90 | 32 | |
paul@90 | 33 | const offset_t DEFAULT_PIPE_SIZE = 4096; |
paul@90 | 34 | |
paul@90 | 35 | |
paul@90 | 36 | |
paul@90 | 37 | /* Close a filesystem object. */ |
paul@90 | 38 | |
paul@90 | 39 | void client_close(file_t *file) |
paul@90 | 40 | { |
paul@90 | 41 | if (file == NULL) |
paul@90 | 42 | return; |
paul@90 | 43 | |
paul@90 | 44 | file_close(file); |
paul@90 | 45 | free(file); |
paul@90 | 46 | } |
paul@90 | 47 | |
paul@90 | 48 | |
paul@90 | 49 | |
paul@90 | 50 | /* Open a filesystem object. */ |
paul@90 | 51 | |
paul@90 | 52 | file_t *client_open(const char *name, flags_t flags) |
paul@90 | 53 | { |
paul@90 | 54 | file_t *file = (file_t *) malloc(sizeof(file_t)); |
paul@90 | 55 | |
paul@90 | 56 | if (file == NULL) |
paul@90 | 57 | return NULL; |
paul@90 | 58 | |
paul@90 | 59 | l4_cap_idx_t server = l4re_env_get_cap("server"); |
paul@90 | 60 | |
paul@90 | 61 | if (file_open(file, name, flags, server)) |
paul@90 | 62 | { |
paul@90 | 63 | free(file); |
paul@90 | 64 | return NULL; |
paul@90 | 65 | } |
paul@90 | 66 | |
paul@90 | 67 | return file; |
paul@90 | 68 | } |
paul@90 | 69 | |
paul@90 | 70 | |
paul@90 | 71 | |
paul@90 | 72 | /* Open a pipe object. */ |
paul@90 | 73 | |
paul@90 | 74 | long client_pipe(file_t **reader, file_t **writer) |
paul@90 | 75 | { |
paul@90 | 76 | *reader = (file_t *) malloc(sizeof(file_t)); |
paul@90 | 77 | |
paul@90 | 78 | if (*reader == NULL) |
paul@90 | 79 | return -L4_ENOMEM; |
paul@90 | 80 | |
paul@90 | 81 | *writer = (file_t *) malloc(sizeof(file_t)); |
paul@90 | 82 | |
paul@90 | 83 | if (*writer == NULL) |
paul@90 | 84 | { |
paul@90 | 85 | free(*reader); |
paul@90 | 86 | return -L4_ENOMEM; |
paul@90 | 87 | } |
paul@90 | 88 | |
paul@90 | 89 | l4_cap_idx_t server = l4re_env_get_cap("pipes"); |
paul@90 | 90 | |
paul@90 | 91 | long err = pipe_open(DEFAULT_PIPE_SIZE, *reader, *writer, server); |
paul@90 | 92 | |
paul@90 | 93 | if (err) |
paul@90 | 94 | { |
paul@90 | 95 | free(*reader); |
paul@90 | 96 | free(*writer); |
paul@90 | 97 | } |
paul@90 | 98 | |
paul@90 | 99 | return err; |
paul@90 | 100 | } |
paul@90 | 101 | |
paul@90 | 102 | |
paul@90 | 103 | |
paul@90 | 104 | /* Flush data conditionally to the filesystem object. */ |
paul@90 | 105 | |
paul@90 | 106 | static long _flush(file_t *file, offset_t position) |
paul@90 | 107 | { |
paul@90 | 108 | long err; |
paul@90 | 109 | |
paul@90 | 110 | /* Where the position is outside the current region, re-map. */ |
paul@90 | 111 | |
paul@90 | 112 | if ((position < file->start_pos) || (position >= file->end_pos)) |
paul@90 | 113 | { |
paul@90 | 114 | if (file->can_mmap) |
paul@90 | 115 | { |
paul@90 | 116 | if (file_mmap(file, position, file_span(file))) |
paul@90 | 117 | return -L4_EIO; |
paul@90 | 118 | } |
paul@90 | 119 | |
paul@90 | 120 | /* Strict conditions for region navigation in pipes. */ |
paul@90 | 121 | |
paul@90 | 122 | else if ((position != file->end_pos) || |
paul@90 | 123 | (client_next_region(file) == NULL)) |
paul@90 | 124 | return -L4_EIO; |
paul@90 | 125 | } |
paul@90 | 126 | |
paul@90 | 127 | /* Otherwise, flush any written data in the current region and update the |
paul@90 | 128 | file size details. */ |
paul@90 | 129 | |
paul@90 | 130 | else |
paul@90 | 131 | { |
paul@90 | 132 | err = client_flush(file); |
paul@90 | 133 | |
paul@90 | 134 | if (err) |
paul@90 | 135 | return err; |
paul@90 | 136 | } |
paul@90 | 137 | |
paul@90 | 138 | /* Update the current data offset. */ |
paul@90 | 139 | |
paul@90 | 140 | file->data_current = position - file->start_pos; |
paul@90 | 141 | return L4_EOK; |
paul@90 | 142 | } |
paul@90 | 143 | |
paul@90 | 144 | |
paul@90 | 145 | |
paul@90 | 146 | /* Flush data explicitly to the filesystem object. */ |
paul@90 | 147 | |
paul@90 | 148 | long client_flush(file_t *file) |
paul@90 | 149 | { |
paul@90 | 150 | if (file == NULL) |
paul@90 | 151 | return -L4_EINVAL; |
paul@90 | 152 | |
paul@90 | 153 | /* Flush and retain most buffer settings. */ |
paul@90 | 154 | |
paul@90 | 155 | return file_flush(file); |
paul@90 | 156 | } |
paul@90 | 157 | |
paul@90 | 158 | |
paul@90 | 159 | |
paul@90 | 160 | /* Map a memory region to a file. */ |
paul@90 | 161 | |
paul@90 | 162 | void *client_mmap(file_t *file, offset_t position, offset_t length) |
paul@90 | 163 | { |
paul@90 | 164 | if ((file == NULL) || (file_mmap(file, position, length))) |
paul@90 | 165 | return NULL; |
paul@90 | 166 | |
paul@90 | 167 | return file->memory; |
paul@90 | 168 | } |
paul@90 | 169 | |
paul@90 | 170 | |
paul@90 | 171 | |
paul@90 | 172 | /* Obtain the current region of a pipe. */ |
paul@90 | 173 | |
paul@90 | 174 | void *client_current_region(file_t *file) |
paul@90 | 175 | { |
paul@90 | 176 | if ((file == NULL) || (pipe_current(file))) |
paul@90 | 177 | return NULL; |
paul@90 | 178 | |
paul@90 | 179 | return file->memory; |
paul@90 | 180 | } |
paul@90 | 181 | |
paul@90 | 182 | |
paul@90 | 183 | |
paul@90 | 184 | /* Obtain the next region of a pipe. */ |
paul@90 | 185 | |
paul@90 | 186 | void *client_next_region(file_t *file) |
paul@90 | 187 | { |
paul@90 | 188 | if ((file == NULL) || (pipe_next(file))) |
paul@90 | 189 | return NULL; |
paul@90 | 190 | |
paul@90 | 191 | return file->memory; |
paul@90 | 192 | } |
paul@90 | 193 | |
paul@90 | 194 | |
paul@90 | 195 | |
paul@90 | 196 | /* Read from the filesystem object into the buffer provided. */ |
paul@90 | 197 | |
paul@90 | 198 | offset_t client_read(file_t *file, void *buf, offset_t count) |
paul@90 | 199 | { |
paul@90 | 200 | if (file == NULL) |
paul@90 | 201 | return 0; |
paul@90 | 202 | |
paul@100 | 203 | /* Map memory if none has been mapped so far. */ |
paul@100 | 204 | |
paul@100 | 205 | if ((file->memory == NULL) && (client_mmap(file, client_tell(file), count) == NULL)) |
paul@100 | 206 | return 0; |
paul@100 | 207 | |
paul@90 | 208 | /* Amount available in the descriptor buffer already. */ |
paul@90 | 209 | |
paul@90 | 210 | offset_t available = file_data_available(file); |
paul@90 | 211 | offset_t to_transfer, total = 0; |
paul@90 | 212 | |
paul@90 | 213 | while (count > 0) |
paul@90 | 214 | { |
paul@90 | 215 | /* If there is no data, try and obtain more data. */ |
paul@90 | 216 | |
paul@90 | 217 | if (!available) |
paul@90 | 218 | { |
paul@90 | 219 | /* Flush any unwritten data, preparing to read from the file position at |
paul@90 | 220 | the end of the data, and returning if no new data is available. */ |
paul@90 | 221 | |
paul@90 | 222 | if (_flush(file, file_data_end_position(file))) |
paul@90 | 223 | break; |
paul@90 | 224 | |
paul@90 | 225 | available = file_data_available(file); |
paul@90 | 226 | |
paul@90 | 227 | if (!available) |
paul@90 | 228 | break; |
paul@90 | 229 | } |
paul@90 | 230 | |
paul@90 | 231 | /* Transfer data into the supplied buffer. */ |
paul@90 | 232 | |
paul@90 | 233 | to_transfer = available <= count ? available : count; |
paul@90 | 234 | |
paul@90 | 235 | file_data_read(file, (char *) buf, to_transfer); |
paul@90 | 236 | |
paul@90 | 237 | /* Update counters. */ |
paul@90 | 238 | |
paul@90 | 239 | available -= to_transfer; |
paul@90 | 240 | |
paul@90 | 241 | count -= to_transfer; |
paul@90 | 242 | total += to_transfer; |
paul@90 | 243 | |
paul@90 | 244 | buf = ((char *) buf + to_transfer); |
paul@90 | 245 | } |
paul@90 | 246 | |
paul@90 | 247 | return total; |
paul@90 | 248 | } |
paul@90 | 249 | |
paul@90 | 250 | |
paul@90 | 251 | |
paul@90 | 252 | /* Ensure that the buffer can provide the needed data. */ |
paul@90 | 253 | |
paul@90 | 254 | offset_t client_seek(file_t *file, offset_t offset, int whence) |
paul@90 | 255 | { |
paul@90 | 256 | if (file == NULL) |
paul@90 | 257 | return 0; |
paul@90 | 258 | |
paul@90 | 259 | offset_t position, current = file_data_current_position(file), change; |
paul@90 | 260 | |
paul@90 | 261 | switch (whence) |
paul@90 | 262 | { |
paul@90 | 263 | case SEEK_SET: |
paul@90 | 264 | position = offset; |
paul@90 | 265 | break; |
paul@90 | 266 | |
paul@90 | 267 | case SEEK_CUR: |
paul@90 | 268 | position = current + offset; |
paul@90 | 269 | break; |
paul@90 | 270 | |
paul@90 | 271 | case SEEK_END: |
paul@90 | 272 | position = file->size + offset; |
paul@90 | 273 | break; |
paul@90 | 274 | |
paul@90 | 275 | default: |
paul@90 | 276 | /* NOTE: Set errno to EINVAL. */ |
paul@90 | 277 | return -1; |
paul@90 | 278 | } |
paul@90 | 279 | |
paul@90 | 280 | /* Retain the current position if unchanged. */ |
paul@90 | 281 | |
paul@90 | 282 | if (position == current) |
paul@90 | 283 | return position; |
paul@90 | 284 | |
paul@90 | 285 | /* Move forward in the file. */ |
paul@90 | 286 | |
paul@90 | 287 | if (position > current) |
paul@90 | 288 | { |
paul@90 | 289 | change = position - current; |
paul@90 | 290 | |
paul@90 | 291 | /* Move towards the end of available data. |
paul@90 | 292 | Request new data if not enough is available. */ |
paul@90 | 293 | |
paul@90 | 294 | if (change <= file_data_available(file)) |
paul@90 | 295 | { |
paul@90 | 296 | file->data_current += change; |
paul@90 | 297 | return position; |
paul@90 | 298 | } |
paul@90 | 299 | } |
paul@90 | 300 | |
paul@90 | 301 | /* Move backward in the file. */ |
paul@90 | 302 | |
paul@90 | 303 | else |
paul@90 | 304 | { |
paul@90 | 305 | change = current - position; |
paul@90 | 306 | |
paul@90 | 307 | /* Move towards the start of available data. |
paul@90 | 308 | Request new data if moving beyond the start of the data. */ |
paul@90 | 309 | |
paul@90 | 310 | if (change <= file->data_current) |
paul@90 | 311 | { |
paul@90 | 312 | file->data_current -= change; |
paul@90 | 313 | return position; |
paul@90 | 314 | } |
paul@90 | 315 | } |
paul@90 | 316 | |
paul@90 | 317 | /* Handle unwritten data and reset the buffer for reading. */ |
paul@90 | 318 | |
paul@90 | 319 | _flush(file, position); |
paul@90 | 320 | return position; |
paul@90 | 321 | } |
paul@90 | 322 | |
paul@90 | 323 | |
paul@90 | 324 | |
paul@90 | 325 | long client_tell(file_t *file) |
paul@90 | 326 | { |
paul@90 | 327 | if (file == NULL) |
paul@90 | 328 | return -L4_EINVAL; |
paul@90 | 329 | |
paul@90 | 330 | return file_data_current_position(file); |
paul@90 | 331 | } |
paul@90 | 332 | |
paul@90 | 333 | |
paul@90 | 334 | |
paul@90 | 335 | /* Write to the filesystem object from the buffer provided. */ |
paul@90 | 336 | |
paul@90 | 337 | offset_t client_write(file_t *file, const void *buf, offset_t count) |
paul@90 | 338 | { |
paul@90 | 339 | if (file == NULL) |
paul@90 | 340 | return 0; |
paul@90 | 341 | |
paul@100 | 342 | /* Map memory if none has been mapped so far. */ |
paul@100 | 343 | |
paul@100 | 344 | if ((file->memory == NULL) && (client_mmap(file, client_tell(file), count) == NULL)) |
paul@100 | 345 | return 0; |
paul@100 | 346 | |
paul@90 | 347 | /* Attempt to ensure that the file can accept the amount of data to be |
paul@90 | 348 | written. This may not resize to the needed amount if a file has a fixed |
paul@90 | 349 | size, but data will still be written to any available space. */ |
paul@90 | 350 | |
paul@90 | 351 | offset_t needed_size = file_data_current_position(file) + count; |
paul@90 | 352 | |
paul@90 | 353 | if (file->size < needed_size) |
paul@90 | 354 | { |
paul@90 | 355 | file_resize(file, needed_size); |
paul@90 | 356 | |
paul@90 | 357 | if (file->size < needed_size) |
paul@90 | 358 | count = file->size - file_data_current_position(file); |
paul@90 | 359 | } |
paul@90 | 360 | |
paul@90 | 361 | /* Space remaining in the descriptor buffer. */ |
paul@90 | 362 | |
paul@90 | 363 | offset_t space = file_data_space(file); |
paul@90 | 364 | offset_t to_transfer, total = 0; |
paul@90 | 365 | |
paul@90 | 366 | while (count > 0) |
paul@90 | 367 | { |
paul@90 | 368 | /* If no space is available, try and send data, reset the buffer. */ |
paul@90 | 369 | |
paul@90 | 370 | if (!space) |
paul@90 | 371 | { |
paul@90 | 372 | /* Flush any unwritten data and continue writing from the current data |
paul@90 | 373 | position. */ |
paul@90 | 374 | |
paul@90 | 375 | if (_flush(file, file_data_current_position(file))) |
paul@90 | 376 | break; |
paul@90 | 377 | |
paul@90 | 378 | space = file_data_space(file); |
paul@90 | 379 | } |
paul@90 | 380 | |
paul@90 | 381 | /* Transfer data into the supplied buffer. */ |
paul@90 | 382 | |
paul@90 | 383 | to_transfer = space <= count ? space : count; |
paul@90 | 384 | |
paul@90 | 385 | file_data_write(file, (char *) buf, to_transfer); |
paul@90 | 386 | |
paul@90 | 387 | /* Update counters. */ |
paul@90 | 388 | |
paul@90 | 389 | space -= to_transfer; |
paul@90 | 390 | |
paul@90 | 391 | count -= to_transfer; |
paul@90 | 392 | total += to_transfer; |
paul@90 | 393 | |
paul@90 | 394 | buf = ((char *) buf + to_transfer); |
paul@90 | 395 | } |
paul@90 | 396 | |
paul@90 | 397 | return total; |
paul@90 | 398 | } |
paul@90 | 399 | |
paul@90 | 400 | // vim: tabstop=2 expandtab shiftwidth=2 |