| 1 | /* Host file transfer support for gdbserver. |
| 2 | Copyright (C) 2007-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | Contributed by CodeSourcery. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "server.h" |
| 22 | #include "gdb/fileio.h" |
| 23 | #include "hostio.h" |
| 24 | |
| 25 | #include <fcntl.h> |
| 26 | #include <limits.h> |
| 27 | #include <unistd.h> |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/stat.h> |
| 30 | #include "gdbsupport/fileio.h" |
| 31 | |
| 32 | struct fd_list |
| 33 | { |
| 34 | int fd; |
| 35 | struct fd_list *next; |
| 36 | }; |
| 37 | |
| 38 | static struct fd_list *open_fds; |
| 39 | |
| 40 | static int |
| 41 | safe_fromhex (char a, int *nibble) |
| 42 | { |
| 43 | if (a >= '0' && a <= '9') |
| 44 | *nibble = a - '0'; |
| 45 | else if (a >= 'a' && a <= 'f') |
| 46 | *nibble = a - 'a' + 10; |
| 47 | else if (a >= 'A' && a <= 'F') |
| 48 | *nibble = a - 'A' + 10; |
| 49 | else |
| 50 | return -1; |
| 51 | |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | /* Filenames are hex encoded, so the maximum we can handle is half the |
| 56 | packet buffer size. Cap to PATH_MAX, if it is shorter. */ |
| 57 | #if !defined (PATH_MAX) || (PATH_MAX > (PBUFSIZ / 2 + 1)) |
| 58 | # define HOSTIO_PATH_MAX (PBUFSIZ / 2 + 1) |
| 59 | #else |
| 60 | # define HOSTIO_PATH_MAX PATH_MAX |
| 61 | #endif |
| 62 | |
| 63 | static int |
| 64 | require_filename (char **pp, char *filename) |
| 65 | { |
| 66 | int count; |
| 67 | char *p; |
| 68 | |
| 69 | p = *pp; |
| 70 | count = 0; |
| 71 | |
| 72 | while (*p && *p != ',') |
| 73 | { |
| 74 | int nib1, nib2; |
| 75 | |
| 76 | /* Don't allow overflow. */ |
| 77 | if (count >= HOSTIO_PATH_MAX - 1) |
| 78 | return -1; |
| 79 | |
| 80 | if (safe_fromhex (p[0], &nib1) |
| 81 | || safe_fromhex (p[1], &nib2)) |
| 82 | return -1; |
| 83 | |
| 84 | filename[count++] = nib1 * 16 + nib2; |
| 85 | p += 2; |
| 86 | } |
| 87 | |
| 88 | filename[count] = '\0'; |
| 89 | *pp = p; |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | static int |
| 94 | require_int (char **pp, int *value) |
| 95 | { |
| 96 | char *p; |
| 97 | int count, firstdigit; |
| 98 | |
| 99 | p = *pp; |
| 100 | *value = 0; |
| 101 | count = 0; |
| 102 | firstdigit = -1; |
| 103 | |
| 104 | while (*p && *p != ',') |
| 105 | { |
| 106 | int nib; |
| 107 | |
| 108 | if (safe_fromhex (p[0], &nib)) |
| 109 | return -1; |
| 110 | |
| 111 | if (firstdigit == -1) |
| 112 | firstdigit = nib; |
| 113 | |
| 114 | /* Don't allow overflow. */ |
| 115 | if (count >= 8 || (count == 7 && firstdigit >= 0x8)) |
| 116 | return -1; |
| 117 | |
| 118 | *value = *value * 16 + nib; |
| 119 | p++; |
| 120 | count++; |
| 121 | } |
| 122 | |
| 123 | *pp = p; |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | static int |
| 128 | require_data (char *p, int p_len, char **data, int *data_len) |
| 129 | { |
| 130 | int input_index, output_index, escaped; |
| 131 | |
| 132 | *data = (char *) xmalloc (p_len); |
| 133 | |
| 134 | output_index = 0; |
| 135 | escaped = 0; |
| 136 | for (input_index = 0; input_index < p_len; input_index++) |
| 137 | { |
| 138 | char b = p[input_index]; |
| 139 | |
| 140 | if (escaped) |
| 141 | { |
| 142 | (*data)[output_index++] = b ^ 0x20; |
| 143 | escaped = 0; |
| 144 | } |
| 145 | else if (b == '}') |
| 146 | escaped = 1; |
| 147 | else |
| 148 | (*data)[output_index++] = b; |
| 149 | } |
| 150 | |
| 151 | if (escaped) |
| 152 | { |
| 153 | free (*data); |
| 154 | return -1; |
| 155 | } |
| 156 | |
| 157 | *data_len = output_index; |
| 158 | return 0; |
| 159 | } |
| 160 | |
| 161 | static int |
| 162 | require_comma (char **pp) |
| 163 | { |
| 164 | if (**pp == ',') |
| 165 | { |
| 166 | (*pp)++; |
| 167 | return 0; |
| 168 | } |
| 169 | else |
| 170 | return -1; |
| 171 | } |
| 172 | |
| 173 | static int |
| 174 | require_end (char *p) |
| 175 | { |
| 176 | if (*p == '\0') |
| 177 | return 0; |
| 178 | else |
| 179 | return -1; |
| 180 | } |
| 181 | |
| 182 | static int |
| 183 | require_valid_fd (int fd) |
| 184 | { |
| 185 | struct fd_list *fd_ptr; |
| 186 | |
| 187 | for (fd_ptr = open_fds; fd_ptr != NULL; fd_ptr = fd_ptr->next) |
| 188 | if (fd_ptr->fd == fd) |
| 189 | return 0; |
| 190 | |
| 191 | return -1; |
| 192 | } |
| 193 | |
| 194 | /* Fill in own_buf with the last hostio error packet, however it |
| 195 | suitable for the target. */ |
| 196 | static void |
| 197 | hostio_error (char *own_buf) |
| 198 | { |
| 199 | the_target->hostio_last_error (own_buf); |
| 200 | } |
| 201 | |
| 202 | static void |
| 203 | hostio_packet_error (char *own_buf) |
| 204 | { |
| 205 | sprintf (own_buf, "F-1,%x", FILEIO_EINVAL); |
| 206 | } |
| 207 | |
| 208 | static void |
| 209 | hostio_reply (char *own_buf, int result) |
| 210 | { |
| 211 | sprintf (own_buf, "F%x", result); |
| 212 | } |
| 213 | |
| 214 | static int |
| 215 | hostio_reply_with_data (char *own_buf, char *buffer, int len, |
| 216 | int *new_packet_len) |
| 217 | { |
| 218 | int input_index, output_index, out_maxlen; |
| 219 | |
| 220 | sprintf (own_buf, "F%x;", len); |
| 221 | output_index = strlen (own_buf); |
| 222 | |
| 223 | out_maxlen = PBUFSIZ; |
| 224 | |
| 225 | for (input_index = 0; input_index < len; input_index++) |
| 226 | { |
| 227 | char b = buffer[input_index]; |
| 228 | |
| 229 | if (b == '$' || b == '#' || b == '}' || b == '*') |
| 230 | { |
| 231 | /* These must be escaped. */ |
| 232 | if (output_index + 2 > out_maxlen) |
| 233 | break; |
| 234 | own_buf[output_index++] = '}'; |
| 235 | own_buf[output_index++] = b ^ 0x20; |
| 236 | } |
| 237 | else |
| 238 | { |
| 239 | if (output_index + 1 > out_maxlen) |
| 240 | break; |
| 241 | own_buf[output_index++] = b; |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | *new_packet_len = output_index; |
| 246 | return input_index; |
| 247 | } |
| 248 | |
| 249 | /* Process ID of inferior whose filesystem hostio functions |
| 250 | that take FILENAME arguments will use. Zero means to use |
| 251 | our own filesystem. */ |
| 252 | |
| 253 | static int hostio_fs_pid; |
| 254 | |
| 255 | /* See hostio.h. */ |
| 256 | |
| 257 | void |
| 258 | hostio_handle_new_gdb_connection (void) |
| 259 | { |
| 260 | hostio_fs_pid = 0; |
| 261 | } |
| 262 | |
| 263 | /* Handle a "vFile:setfs:" packet. */ |
| 264 | |
| 265 | static void |
| 266 | handle_setfs (char *own_buf) |
| 267 | { |
| 268 | char *p; |
| 269 | int pid; |
| 270 | |
| 271 | /* If the target doesn't have any of the in-filesystem-of methods |
| 272 | then there's no point in GDB sending "vFile:setfs:" packets. We |
| 273 | reply with an empty packet (i.e. we pretend we don't understand |
| 274 | "vFile:setfs:") and that should stop GDB sending any more. */ |
| 275 | if (!the_target->supports_multifs ()) |
| 276 | { |
| 277 | own_buf[0] = '\0'; |
| 278 | return; |
| 279 | } |
| 280 | |
| 281 | p = own_buf + strlen ("vFile:setfs:"); |
| 282 | |
| 283 | if (require_int (&p, &pid) |
| 284 | || pid < 0 |
| 285 | || require_end (p)) |
| 286 | { |
| 287 | hostio_packet_error (own_buf); |
| 288 | return; |
| 289 | } |
| 290 | |
| 291 | hostio_fs_pid = pid; |
| 292 | |
| 293 | hostio_reply (own_buf, 0); |
| 294 | } |
| 295 | |
| 296 | static void |
| 297 | handle_open (char *own_buf) |
| 298 | { |
| 299 | char filename[HOSTIO_PATH_MAX]; |
| 300 | char *p; |
| 301 | int fileio_flags, fileio_mode, flags, fd; |
| 302 | mode_t mode; |
| 303 | struct fd_list *new_fd; |
| 304 | |
| 305 | p = own_buf + strlen ("vFile:open:"); |
| 306 | |
| 307 | if (require_filename (&p, filename) |
| 308 | || require_comma (&p) |
| 309 | || require_int (&p, &fileio_flags) |
| 310 | || require_comma (&p) |
| 311 | || require_int (&p, &fileio_mode) |
| 312 | || require_end (p) |
| 313 | || fileio_to_host_openflags (fileio_flags, &flags) |
| 314 | || fileio_to_host_mode (fileio_mode, &mode)) |
| 315 | { |
| 316 | hostio_packet_error (own_buf); |
| 317 | return; |
| 318 | } |
| 319 | |
| 320 | /* We do not need to convert MODE, since the fileio protocol |
| 321 | uses the standard values. */ |
| 322 | if (hostio_fs_pid != 0) |
| 323 | fd = the_target->multifs_open (hostio_fs_pid, filename, flags, mode); |
| 324 | else |
| 325 | fd = open (filename, flags, mode); |
| 326 | |
| 327 | if (fd == -1) |
| 328 | { |
| 329 | hostio_error (own_buf); |
| 330 | return; |
| 331 | } |
| 332 | |
| 333 | /* Record the new file descriptor. */ |
| 334 | new_fd = XNEW (struct fd_list); |
| 335 | new_fd->fd = fd; |
| 336 | new_fd->next = open_fds; |
| 337 | open_fds = new_fd; |
| 338 | |
| 339 | hostio_reply (own_buf, fd); |
| 340 | } |
| 341 | |
| 342 | static void |
| 343 | handle_pread (char *own_buf, int *new_packet_len) |
| 344 | { |
| 345 | int fd, ret, len, offset, bytes_sent; |
| 346 | char *p, *data; |
| 347 | static int max_reply_size = -1; |
| 348 | |
| 349 | p = own_buf + strlen ("vFile:pread:"); |
| 350 | |
| 351 | if (require_int (&p, &fd) |
| 352 | || require_comma (&p) |
| 353 | || require_valid_fd (fd) |
| 354 | || require_int (&p, &len) |
| 355 | || require_comma (&p) |
| 356 | || require_int (&p, &offset) |
| 357 | || require_end (p)) |
| 358 | { |
| 359 | hostio_packet_error (own_buf); |
| 360 | return; |
| 361 | } |
| 362 | |
| 363 | /* Do not attempt to read more than the maximum number of bytes |
| 364 | hostio_reply_with_data can fit in a packet. We may still read |
| 365 | too much because of escaping, but this is handled below. */ |
| 366 | if (max_reply_size == -1) |
| 367 | { |
| 368 | sprintf (own_buf, "F%x;", PBUFSIZ); |
| 369 | max_reply_size = PBUFSIZ - strlen (own_buf); |
| 370 | } |
| 371 | if (len > max_reply_size) |
| 372 | len = max_reply_size; |
| 373 | |
| 374 | data = (char *) xmalloc (len); |
| 375 | #ifdef HAVE_PREAD |
| 376 | ret = pread (fd, data, len, offset); |
| 377 | #else |
| 378 | ret = -1; |
| 379 | #endif |
| 380 | /* If we have no pread or it failed for this file, use lseek/read. */ |
| 381 | if (ret == -1) |
| 382 | { |
| 383 | ret = lseek (fd, offset, SEEK_SET); |
| 384 | if (ret != -1) |
| 385 | ret = read (fd, data, len); |
| 386 | } |
| 387 | |
| 388 | if (ret == -1) |
| 389 | { |
| 390 | hostio_error (own_buf); |
| 391 | free (data); |
| 392 | return; |
| 393 | } |
| 394 | |
| 395 | bytes_sent = hostio_reply_with_data (own_buf, data, ret, new_packet_len); |
| 396 | |
| 397 | /* If we were using read, and the data did not all fit in the reply, |
| 398 | we would have to back up using lseek here. With pread it does |
| 399 | not matter. But we still have a problem; the return value in the |
| 400 | packet might be wrong, so we must fix it. This time it will |
| 401 | definitely fit. */ |
| 402 | if (bytes_sent < ret) |
| 403 | bytes_sent = hostio_reply_with_data (own_buf, data, bytes_sent, |
| 404 | new_packet_len); |
| 405 | |
| 406 | free (data); |
| 407 | } |
| 408 | |
| 409 | static void |
| 410 | handle_pwrite (char *own_buf, int packet_len) |
| 411 | { |
| 412 | int fd, ret, len, offset; |
| 413 | char *p, *data; |
| 414 | |
| 415 | p = own_buf + strlen ("vFile:pwrite:"); |
| 416 | |
| 417 | if (require_int (&p, &fd) |
| 418 | || require_comma (&p) |
| 419 | || require_valid_fd (fd) |
| 420 | || require_int (&p, &offset) |
| 421 | || require_comma (&p) |
| 422 | || require_data (p, packet_len - (p - own_buf), &data, &len)) |
| 423 | { |
| 424 | hostio_packet_error (own_buf); |
| 425 | return; |
| 426 | } |
| 427 | |
| 428 | #ifdef HAVE_PWRITE |
| 429 | ret = pwrite (fd, data, len, offset); |
| 430 | #else |
| 431 | ret = -1; |
| 432 | #endif |
| 433 | /* If we have no pwrite or it failed for this file, use lseek/write. */ |
| 434 | if (ret == -1) |
| 435 | { |
| 436 | ret = lseek (fd, offset, SEEK_SET); |
| 437 | if (ret != -1) |
| 438 | ret = write (fd, data, len); |
| 439 | } |
| 440 | |
| 441 | if (ret == -1) |
| 442 | { |
| 443 | hostio_error (own_buf); |
| 444 | free (data); |
| 445 | return; |
| 446 | } |
| 447 | |
| 448 | hostio_reply (own_buf, ret); |
| 449 | free (data); |
| 450 | } |
| 451 | |
| 452 | static void |
| 453 | handle_fstat (char *own_buf, int *new_packet_len) |
| 454 | { |
| 455 | int fd, bytes_sent; |
| 456 | char *p; |
| 457 | struct stat st; |
| 458 | struct fio_stat fst; |
| 459 | |
| 460 | p = own_buf + strlen ("vFile:fstat:"); |
| 461 | |
| 462 | if (require_int (&p, &fd) |
| 463 | || require_valid_fd (fd) |
| 464 | || require_end (p)) |
| 465 | { |
| 466 | hostio_packet_error (own_buf); |
| 467 | return; |
| 468 | } |
| 469 | |
| 470 | if (fstat (fd, &st) == -1) |
| 471 | { |
| 472 | hostio_error (own_buf); |
| 473 | return; |
| 474 | } |
| 475 | |
| 476 | host_to_fileio_stat (&st, &fst); |
| 477 | |
| 478 | bytes_sent = hostio_reply_with_data (own_buf, |
| 479 | (char *) &fst, sizeof (fst), |
| 480 | new_packet_len); |
| 481 | |
| 482 | /* If the response does not fit into a single packet, do not attempt |
| 483 | to return a partial response, but simply fail. */ |
| 484 | if (bytes_sent < sizeof (fst)) |
| 485 | write_enn (own_buf); |
| 486 | } |
| 487 | |
| 488 | static void |
| 489 | handle_close (char *own_buf) |
| 490 | { |
| 491 | int fd, ret; |
| 492 | char *p; |
| 493 | struct fd_list **open_fd_p, *old_fd; |
| 494 | |
| 495 | p = own_buf + strlen ("vFile:close:"); |
| 496 | |
| 497 | if (require_int (&p, &fd) |
| 498 | || require_valid_fd (fd) |
| 499 | || require_end (p)) |
| 500 | { |
| 501 | hostio_packet_error (own_buf); |
| 502 | return; |
| 503 | } |
| 504 | |
| 505 | ret = close (fd); |
| 506 | |
| 507 | if (ret == -1) |
| 508 | { |
| 509 | hostio_error (own_buf); |
| 510 | return; |
| 511 | } |
| 512 | |
| 513 | open_fd_p = &open_fds; |
| 514 | /* We know that fd is in the list, thanks to require_valid_fd. */ |
| 515 | while ((*open_fd_p)->fd != fd) |
| 516 | open_fd_p = &(*open_fd_p)->next; |
| 517 | |
| 518 | old_fd = *open_fd_p; |
| 519 | *open_fd_p = (*open_fd_p)->next; |
| 520 | free (old_fd); |
| 521 | |
| 522 | hostio_reply (own_buf, ret); |
| 523 | } |
| 524 | |
| 525 | static void |
| 526 | handle_unlink (char *own_buf) |
| 527 | { |
| 528 | char filename[HOSTIO_PATH_MAX]; |
| 529 | char *p; |
| 530 | int ret; |
| 531 | |
| 532 | p = own_buf + strlen ("vFile:unlink:"); |
| 533 | |
| 534 | if (require_filename (&p, filename) |
| 535 | || require_end (p)) |
| 536 | { |
| 537 | hostio_packet_error (own_buf); |
| 538 | return; |
| 539 | } |
| 540 | |
| 541 | if (hostio_fs_pid != 0) |
| 542 | ret = the_target->multifs_unlink (hostio_fs_pid, filename); |
| 543 | else |
| 544 | ret = unlink (filename); |
| 545 | |
| 546 | if (ret == -1) |
| 547 | { |
| 548 | hostio_error (own_buf); |
| 549 | return; |
| 550 | } |
| 551 | |
| 552 | hostio_reply (own_buf, ret); |
| 553 | } |
| 554 | |
| 555 | static void |
| 556 | handle_readlink (char *own_buf, int *new_packet_len) |
| 557 | { |
| 558 | char filename[HOSTIO_PATH_MAX], linkname[HOSTIO_PATH_MAX]; |
| 559 | char *p; |
| 560 | int ret, bytes_sent; |
| 561 | |
| 562 | p = own_buf + strlen ("vFile:readlink:"); |
| 563 | |
| 564 | if (require_filename (&p, filename) |
| 565 | || require_end (p)) |
| 566 | { |
| 567 | hostio_packet_error (own_buf); |
| 568 | return; |
| 569 | } |
| 570 | |
| 571 | if (hostio_fs_pid != 0) |
| 572 | ret = the_target->multifs_readlink (hostio_fs_pid, filename, |
| 573 | linkname, |
| 574 | sizeof (linkname) - 1); |
| 575 | else |
| 576 | ret = readlink (filename, linkname, sizeof (linkname) - 1); |
| 577 | |
| 578 | if (ret == -1) |
| 579 | { |
| 580 | hostio_error (own_buf); |
| 581 | return; |
| 582 | } |
| 583 | |
| 584 | bytes_sent = hostio_reply_with_data (own_buf, linkname, ret, new_packet_len); |
| 585 | |
| 586 | /* If the response does not fit into a single packet, do not attempt |
| 587 | to return a partial response, but simply fail. */ |
| 588 | if (bytes_sent < ret) |
| 589 | sprintf (own_buf, "F-1,%x", FILEIO_ENAMETOOLONG); |
| 590 | } |
| 591 | |
| 592 | /* Handle all the 'F' file transfer packets. */ |
| 593 | |
| 594 | int |
| 595 | handle_vFile (char *own_buf, int packet_len, int *new_packet_len) |
| 596 | { |
| 597 | if (startswith (own_buf, "vFile:open:")) |
| 598 | handle_open (own_buf); |
| 599 | else if (startswith (own_buf, "vFile:pread:")) |
| 600 | handle_pread (own_buf, new_packet_len); |
| 601 | else if (startswith (own_buf, "vFile:pwrite:")) |
| 602 | handle_pwrite (own_buf, packet_len); |
| 603 | else if (startswith (own_buf, "vFile:fstat:")) |
| 604 | handle_fstat (own_buf, new_packet_len); |
| 605 | else if (startswith (own_buf, "vFile:close:")) |
| 606 | handle_close (own_buf); |
| 607 | else if (startswith (own_buf, "vFile:unlink:")) |
| 608 | handle_unlink (own_buf); |
| 609 | else if (startswith (own_buf, "vFile:readlink:")) |
| 610 | handle_readlink (own_buf, new_packet_len); |
| 611 | else if (startswith (own_buf, "vFile:setfs:")) |
| 612 | handle_setfs (own_buf); |
| 613 | else |
| 614 | return 0; |
| 615 | |
| 616 | return 1; |
| 617 | } |