| 1 | /* libltt |
| 2 | * |
| 3 | * Linux Trace Toolkit Netlink Control Library |
| 4 | * |
| 5 | * Controls the ltt-control kernel module through debugfs. |
| 6 | * |
| 7 | * Copyright 2005 - |
| 8 | * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 9 | * |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License as published by |
| 13 | * the Free Software Foundation; either version 2 of the License, or |
| 14 | * (at your option) any later version. |
| 15 | * |
| 16 | * This program is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU General Public License for more details. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #ifdef HAVE_CONFIG_H |
| 24 | #include <config.h> |
| 25 | #endif |
| 26 | |
| 27 | #include <liblttctl/lttctl.h> |
| 28 | #include <errno.h> |
| 29 | #include <stdio.h> |
| 30 | #include <string.h> |
| 31 | #include <dirent.h> |
| 32 | #include <limits.h> |
| 33 | #include <fcntl.h> |
| 34 | #include <stdlib.h> |
| 35 | |
| 36 | #define MAX_CHANNEL (256) |
| 37 | |
| 38 | static char debugfsmntdir[PATH_MAX]; |
| 39 | |
| 40 | static int initdebugfsmntdir(void) |
| 41 | { |
| 42 | return getdebugfsmntdir(debugfsmntdir); |
| 43 | } |
| 44 | |
| 45 | /* |
| 46 | * This function must called posterior to initdebugfsmntdir(), |
| 47 | * because it need to use debugfsmntdir[] which is inited in initdebugfsmntdir() |
| 48 | */ |
| 49 | static int initmodule(void) |
| 50 | { |
| 51 | char controldirname[PATH_MAX]; |
| 52 | DIR *dir; |
| 53 | int tryload_done = 0; |
| 54 | |
| 55 | sprintf(controldirname, "%s/ltt/control/", debugfsmntdir); |
| 56 | |
| 57 | check_again: |
| 58 | /* |
| 59 | * Check ltt control's debugfs dir |
| 60 | * |
| 61 | * We don't check is ltt-trace-control module exist, because it maybe |
| 62 | * compiled into kernel. |
| 63 | */ |
| 64 | dir = opendir(controldirname); |
| 65 | if (dir) { |
| 66 | closedir(dir); |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | if (!tryload_done) { |
| 71 | system("modprobe ltt-trace-control"); |
| 72 | tryload_done = 1; |
| 73 | goto check_again; |
| 74 | } |
| 75 | |
| 76 | return -ENOENT; |
| 77 | } |
| 78 | |
| 79 | int lttctl_init(void) |
| 80 | { |
| 81 | int ret; |
| 82 | |
| 83 | |
| 84 | ret = initdebugfsmntdir(); |
| 85 | if (ret) { |
| 86 | fprintf(stderr, "Get debugfs mount point failed\n"); |
| 87 | return 1; |
| 88 | } |
| 89 | |
| 90 | ret = initmodule(); |
| 91 | if (ret) { |
| 92 | fprintf(stderr, "Control module seems not work\n"); |
| 93 | return 1; |
| 94 | } |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | int lttctl_destroy(void) |
| 100 | { |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | static int lttctl_sendop(const char *fname, const char *op) |
| 105 | { |
| 106 | int fd; |
| 107 | |
| 108 | if (!fname) { |
| 109 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 110 | return 1; |
| 111 | } |
| 112 | |
| 113 | fd = open(fname, O_WRONLY); |
| 114 | if (fd == -1) { |
| 115 | fprintf(stderr, "%s: open %s failed: %s\n", __func__, fname, |
| 116 | strerror(errno)); |
| 117 | return errno; |
| 118 | } |
| 119 | |
| 120 | if (write(fd, op, strlen(op)) == -1) { |
| 121 | fprintf(stderr, "%s: write %s to %s failed: %s\n", __func__, op, |
| 122 | fname, strerror(errno)); |
| 123 | close(fd); |
| 124 | return 1; |
| 125 | } |
| 126 | |
| 127 | close(fd); |
| 128 | |
| 129 | return 0; |
| 130 | } |
| 131 | |
| 132 | /* |
| 133 | * check is trace exist(check debugfsmntdir too) |
| 134 | * expect: |
| 135 | * 0: expect that trace not exist |
| 136 | * !0: expect that trace exist |
| 137 | * |
| 138 | * ret: |
| 139 | * 0: check pass |
| 140 | * 1: check failed |
| 141 | * -ERRNO: error happened (no check) |
| 142 | */ |
| 143 | static int lttctl_check_trace(const char *name, int expect) |
| 144 | { |
| 145 | char tracedirname[PATH_MAX]; |
| 146 | DIR *dir; |
| 147 | int exist; |
| 148 | |
| 149 | if (!name) { |
| 150 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 151 | return -EINVAL; |
| 152 | } |
| 153 | |
| 154 | if (!debugfsmntdir[0]) { |
| 155 | fprintf(stderr, "%s: debugfsmntdir not valid\n", __func__); |
| 156 | return -EINVAL; |
| 157 | } |
| 158 | |
| 159 | sprintf(tracedirname, "%s/ltt/control/%s", debugfsmntdir, name); |
| 160 | |
| 161 | dir = opendir(tracedirname); |
| 162 | if (dir) { |
| 163 | exist = 1; |
| 164 | } else { |
| 165 | if (errno != ENOENT) { |
| 166 | fprintf(stderr, "%s: %s\n", __func__, strerror(errno)); |
| 167 | return -EINVAL; |
| 168 | } |
| 169 | exist = 0; |
| 170 | } |
| 171 | |
| 172 | closedir(dir); |
| 173 | |
| 174 | if (!expect != !exist) { |
| 175 | if (exist) |
| 176 | fprintf(stderr, "Trace %s already exist\n", name); |
| 177 | else |
| 178 | fprintf(stderr, "Trace %s not exist\n", name); |
| 179 | return 1; |
| 180 | } |
| 181 | |
| 182 | return 0; |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * get channel list of a trace |
| 187 | * don't include metadata channel when metadata is 0 |
| 188 | * |
| 189 | * return number of channel on success |
| 190 | * return negative number on fail |
| 191 | * Caller must free channellist. |
| 192 | */ |
| 193 | static int lttctl_get_channellist(const char *tracename, |
| 194 | char ***channellist, int metadata) |
| 195 | { |
| 196 | char tracedirname[PATH_MAX]; |
| 197 | struct dirent *dirent; |
| 198 | DIR *dir; |
| 199 | char **list = NULL, **old_list; |
| 200 | int nr_chan = 0; |
| 201 | |
| 202 | sprintf(tracedirname, "%s/ltt/control/%s/channel", debugfsmntdir, |
| 203 | tracename); |
| 204 | |
| 205 | dir = opendir(tracedirname); |
| 206 | if (!dir) { |
| 207 | nr_chan = -ENOENT; |
| 208 | goto error; |
| 209 | } |
| 210 | |
| 211 | for (;;) { |
| 212 | dirent = readdir(dir); |
| 213 | if (!dirent) |
| 214 | break; |
| 215 | if (!strcmp(dirent->d_name, ".") |
| 216 | || !strcmp(dirent->d_name, "..")) |
| 217 | continue; |
| 218 | if (!metadata && !strcmp(dirent->d_name, "metadata")) |
| 219 | continue; |
| 220 | old_list = list; |
| 221 | list = malloc(sizeof(char *) * ++nr_chan); |
| 222 | memcpy(list, old_list, sizeof(*list) * (nr_chan - 1)); |
| 223 | free(old_list); |
| 224 | list[nr_chan - 1] = strdup(dirent->d_name); |
| 225 | } |
| 226 | |
| 227 | closedir(dir); |
| 228 | |
| 229 | *channellist = list; |
| 230 | return nr_chan; |
| 231 | error: |
| 232 | free(list); |
| 233 | *channellist = NULL; |
| 234 | return nr_chan; |
| 235 | } |
| 236 | |
| 237 | int lttctl_setup_trace(const char *name) |
| 238 | { |
| 239 | int ret; |
| 240 | char ctlfname[PATH_MAX]; |
| 241 | |
| 242 | if (!name) { |
| 243 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 244 | ret = -EINVAL; |
| 245 | goto arg_error; |
| 246 | } |
| 247 | |
| 248 | ret = lttctl_check_trace(name, 0); |
| 249 | if (ret) |
| 250 | goto arg_error; |
| 251 | |
| 252 | sprintf(ctlfname, "%s/ltt/setup_trace", debugfsmntdir); |
| 253 | |
| 254 | ret = lttctl_sendop(ctlfname, name); |
| 255 | if (ret) { |
| 256 | fprintf(stderr, "Setup trace failed\n"); |
| 257 | goto op_err; |
| 258 | } |
| 259 | |
| 260 | return 0; |
| 261 | |
| 262 | op_err: |
| 263 | arg_error: |
| 264 | return ret; |
| 265 | } |
| 266 | |
| 267 | int lttctl_destroy_trace(const char *name) |
| 268 | { |
| 269 | int ret; |
| 270 | char ctlfname[PATH_MAX]; |
| 271 | |
| 272 | if (!name) { |
| 273 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 274 | ret = -EINVAL; |
| 275 | goto arg_error; |
| 276 | } |
| 277 | |
| 278 | ret = lttctl_check_trace(name, 1); |
| 279 | if (ret) |
| 280 | goto arg_error; |
| 281 | |
| 282 | sprintf(ctlfname, "%s/ltt/destroy_trace", debugfsmntdir); |
| 283 | |
| 284 | ret = lttctl_sendop(ctlfname, name); |
| 285 | if (ret) { |
| 286 | fprintf(stderr, "Destroy trace failed\n"); |
| 287 | goto op_err; |
| 288 | } |
| 289 | |
| 290 | return 0; |
| 291 | |
| 292 | op_err: |
| 293 | arg_error: |
| 294 | return ret; |
| 295 | } |
| 296 | |
| 297 | int lttctl_alloc_trace(const char *name) |
| 298 | { |
| 299 | int ret; |
| 300 | char ctlfname[PATH_MAX]; |
| 301 | |
| 302 | if (!name) { |
| 303 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 304 | ret = -EINVAL; |
| 305 | goto arg_error; |
| 306 | } |
| 307 | |
| 308 | ret = lttctl_check_trace(name, 1); |
| 309 | if (ret) |
| 310 | goto arg_error; |
| 311 | |
| 312 | sprintf(ctlfname, "%s/ltt/control/%s/alloc", debugfsmntdir, name); |
| 313 | |
| 314 | ret = lttctl_sendop(ctlfname, "1"); |
| 315 | if (ret) { |
| 316 | fprintf(stderr, "Allocate trace failed\n"); |
| 317 | goto op_err; |
| 318 | } |
| 319 | |
| 320 | return 0; |
| 321 | |
| 322 | op_err: |
| 323 | arg_error: |
| 324 | return ret; |
| 325 | } |
| 326 | |
| 327 | int lttctl_start(const char *name) |
| 328 | { |
| 329 | int ret; |
| 330 | char ctlfname[PATH_MAX]; |
| 331 | |
| 332 | if (!name) { |
| 333 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 334 | ret = -EINVAL; |
| 335 | goto arg_error; |
| 336 | } |
| 337 | |
| 338 | ret = lttctl_check_trace(name, 1); |
| 339 | if (ret) |
| 340 | goto arg_error; |
| 341 | |
| 342 | sprintf(ctlfname, "%s/ltt/control/%s/enabled", debugfsmntdir, name); |
| 343 | |
| 344 | ret = lttctl_sendop(ctlfname, "1"); |
| 345 | if (ret) { |
| 346 | fprintf(stderr, "Start trace failed\n"); |
| 347 | goto op_err; |
| 348 | } |
| 349 | |
| 350 | return 0; |
| 351 | |
| 352 | op_err: |
| 353 | arg_error: |
| 354 | return ret; |
| 355 | } |
| 356 | |
| 357 | int lttctl_pause(const char *name) |
| 358 | { |
| 359 | int ret; |
| 360 | char ctlfname[PATH_MAX]; |
| 361 | |
| 362 | if (!name) { |
| 363 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 364 | ret = -EINVAL; |
| 365 | goto arg_error; |
| 366 | } |
| 367 | |
| 368 | ret = lttctl_check_trace(name, 1); |
| 369 | if (ret) |
| 370 | goto arg_error; |
| 371 | |
| 372 | sprintf(ctlfname, "%s/ltt/control/%s/enabled", debugfsmntdir, name); |
| 373 | |
| 374 | ret = lttctl_sendop(ctlfname, "0"); |
| 375 | if (ret) { |
| 376 | fprintf(stderr, "Pause trace failed\n"); |
| 377 | goto op_err; |
| 378 | } |
| 379 | |
| 380 | return 0; |
| 381 | |
| 382 | op_err: |
| 383 | arg_error: |
| 384 | return ret; |
| 385 | } |
| 386 | |
| 387 | int lttctl_set_trans(const char *name, const char *trans) |
| 388 | { |
| 389 | int ret; |
| 390 | char ctlfname[PATH_MAX]; |
| 391 | |
| 392 | if (!name) { |
| 393 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 394 | ret = -EINVAL; |
| 395 | goto arg_error; |
| 396 | } |
| 397 | |
| 398 | ret = lttctl_check_trace(name, 1); |
| 399 | if (ret) |
| 400 | goto arg_error; |
| 401 | |
| 402 | sprintf(ctlfname, "%s/ltt/control/%s/trans", debugfsmntdir, name); |
| 403 | |
| 404 | ret = lttctl_sendop(ctlfname, trans); |
| 405 | if (ret) { |
| 406 | fprintf(stderr, "Set transport failed\n"); |
| 407 | goto op_err; |
| 408 | } |
| 409 | |
| 410 | return 0; |
| 411 | |
| 412 | op_err: |
| 413 | arg_error: |
| 414 | return ret; |
| 415 | } |
| 416 | |
| 417 | static int __lttctl_set_channel_enable(const char *name, const char *channel, |
| 418 | int enable) |
| 419 | { |
| 420 | int ret; |
| 421 | char ctlfname[PATH_MAX]; |
| 422 | |
| 423 | sprintf(ctlfname, "%s/ltt/control/%s/channel/%s/enable", debugfsmntdir, |
| 424 | name, channel); |
| 425 | |
| 426 | ret = lttctl_sendop(ctlfname, enable ? "1" : "0"); |
| 427 | if (ret) |
| 428 | fprintf(stderr, "Set channel's enable mode failed\n"); |
| 429 | |
| 430 | return ret; |
| 431 | } |
| 432 | int lttctl_set_channel_enable(const char *name, const char *channel, |
| 433 | int enable) |
| 434 | { |
| 435 | int ret; |
| 436 | |
| 437 | if (!name || !channel) { |
| 438 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 439 | ret = -EINVAL; |
| 440 | goto arg_error; |
| 441 | } |
| 442 | |
| 443 | ret = lttctl_check_trace(name, 1); |
| 444 | if (ret) |
| 445 | goto arg_error; |
| 446 | |
| 447 | if (strcmp(channel, "all")) { |
| 448 | ret = __lttctl_set_channel_enable(name, channel, enable); |
| 449 | if (ret) |
| 450 | goto op_err; |
| 451 | } else { |
| 452 | char **channellist; |
| 453 | int n_channel; |
| 454 | |
| 455 | /* Don't allow set enable state for metadata channel */ |
| 456 | n_channel = lttctl_get_channellist(name, &channellist, 0); |
| 457 | if (n_channel < 0) { |
| 458 | fprintf(stderr, "%s: lttctl_get_channellist failed\n", |
| 459 | __func__); |
| 460 | ret = -ENOENT; |
| 461 | goto op_err; |
| 462 | } |
| 463 | |
| 464 | for (; n_channel > 0; n_channel--) { |
| 465 | ret = __lttctl_set_channel_enable(name, |
| 466 | channellist[n_channel - 1], enable); |
| 467 | if (ret) |
| 468 | goto op_err; |
| 469 | } |
| 470 | free(channellist); |
| 471 | } |
| 472 | |
| 473 | return 0; |
| 474 | |
| 475 | op_err: |
| 476 | arg_error: |
| 477 | return ret; |
| 478 | } |
| 479 | |
| 480 | static int __lttctl_set_channel_overwrite(const char *name, const char *channel, |
| 481 | int overwrite) |
| 482 | { |
| 483 | int ret; |
| 484 | char ctlfname[PATH_MAX]; |
| 485 | |
| 486 | sprintf(ctlfname, "%s/ltt/control/%s/channel/%s/overwrite", |
| 487 | debugfsmntdir, name, channel); |
| 488 | |
| 489 | ret = lttctl_sendop(ctlfname, overwrite ? "1" : "0"); |
| 490 | if (ret) |
| 491 | fprintf(stderr, "Set channel's overwrite mode failed\n"); |
| 492 | |
| 493 | return ret; |
| 494 | } |
| 495 | int lttctl_set_channel_overwrite(const char *name, const char *channel, |
| 496 | int overwrite) |
| 497 | { |
| 498 | int ret; |
| 499 | |
| 500 | if (!name || !channel) { |
| 501 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 502 | ret = -EINVAL; |
| 503 | goto arg_error; |
| 504 | } |
| 505 | |
| 506 | ret = lttctl_check_trace(name, 1); |
| 507 | if (ret) |
| 508 | goto arg_error; |
| 509 | |
| 510 | if (strcmp(channel, "all")) { |
| 511 | ret = __lttctl_set_channel_overwrite(name, channel, overwrite); |
| 512 | if (ret) |
| 513 | goto op_err; |
| 514 | } else { |
| 515 | char **channellist; |
| 516 | int n_channel; |
| 517 | |
| 518 | /* Don't allow set overwrite for metadata channel */ |
| 519 | n_channel = lttctl_get_channellist(name, &channellist, 0); |
| 520 | if (n_channel < 0) { |
| 521 | fprintf(stderr, "%s: lttctl_get_channellist failed\n", |
| 522 | __func__); |
| 523 | ret = -ENOENT; |
| 524 | goto op_err; |
| 525 | } |
| 526 | |
| 527 | for (; n_channel > 0; n_channel--) { |
| 528 | ret = __lttctl_set_channel_overwrite(name, |
| 529 | channellist[n_channel - 1], overwrite); |
| 530 | if (ret) |
| 531 | goto op_err; |
| 532 | } |
| 533 | free(channellist); |
| 534 | } |
| 535 | |
| 536 | return 0; |
| 537 | |
| 538 | op_err: |
| 539 | arg_error: |
| 540 | return ret; |
| 541 | } |
| 542 | |
| 543 | static int __lttctl_set_channel_subbuf_num(const char *name, |
| 544 | const char *channel, unsigned subbuf_num) |
| 545 | { |
| 546 | int ret; |
| 547 | char ctlfname[PATH_MAX]; |
| 548 | char opstr[32]; |
| 549 | |
| 550 | sprintf(ctlfname, "%s/ltt/control/%s/channel/%s/subbuf_num", |
| 551 | debugfsmntdir, name, channel); |
| 552 | |
| 553 | sprintf(opstr, "%u", subbuf_num); |
| 554 | |
| 555 | ret = lttctl_sendop(ctlfname, opstr); |
| 556 | if (ret) |
| 557 | fprintf(stderr, "Set channel's subbuf number failed\n"); |
| 558 | |
| 559 | return ret; |
| 560 | } |
| 561 | int lttctl_set_channel_subbuf_num(const char *name, const char *channel, |
| 562 | unsigned subbuf_num) |
| 563 | { |
| 564 | int ret; |
| 565 | |
| 566 | if (!name || !channel) { |
| 567 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 568 | ret = -EINVAL; |
| 569 | goto arg_error; |
| 570 | } |
| 571 | |
| 572 | ret = lttctl_check_trace(name, 1); |
| 573 | if (ret) |
| 574 | goto arg_error; |
| 575 | |
| 576 | if (strcmp(channel, "all")) { |
| 577 | ret = __lttctl_set_channel_subbuf_num(name, channel, |
| 578 | subbuf_num); |
| 579 | if (ret) |
| 580 | goto op_err; |
| 581 | } else { |
| 582 | char **channellist; |
| 583 | int n_channel; |
| 584 | |
| 585 | /* allow set subbuf_num for metadata channel */ |
| 586 | n_channel = lttctl_get_channellist(name, &channellist, 1); |
| 587 | if (n_channel < 0) { |
| 588 | fprintf(stderr, "%s: lttctl_get_channellist failed\n", |
| 589 | __func__); |
| 590 | ret = -ENOENT; |
| 591 | goto op_err; |
| 592 | } |
| 593 | |
| 594 | for (; n_channel > 0; n_channel--) { |
| 595 | ret = __lttctl_set_channel_subbuf_num(name, |
| 596 | channellist[n_channel - 1], subbuf_num); |
| 597 | if (ret) |
| 598 | goto op_err; |
| 599 | } |
| 600 | free(channellist); |
| 601 | } |
| 602 | |
| 603 | return 0; |
| 604 | |
| 605 | op_err: |
| 606 | arg_error: |
| 607 | return ret; |
| 608 | } |
| 609 | |
| 610 | static int __lttctl_set_channel_subbuf_size(const char *name, |
| 611 | const char *channel, unsigned subbuf_size) |
| 612 | { |
| 613 | int ret; |
| 614 | char ctlfname[PATH_MAX]; |
| 615 | char opstr[32]; |
| 616 | |
| 617 | sprintf(ctlfname, "%s/ltt/control/%s/channel/%s/subbuf_size", |
| 618 | debugfsmntdir, name, channel); |
| 619 | |
| 620 | sprintf(opstr, "%u", subbuf_size); |
| 621 | |
| 622 | ret = lttctl_sendop(ctlfname, opstr); |
| 623 | if (ret) |
| 624 | fprintf(stderr, "Set channel's subbuf size failed\n"); |
| 625 | } |
| 626 | int lttctl_set_channel_subbuf_size(const char *name, const char *channel, |
| 627 | unsigned subbuf_size) |
| 628 | { |
| 629 | int ret; |
| 630 | |
| 631 | if (!name || !channel) { |
| 632 | fprintf(stderr, "%s: args invalid\n", __func__); |
| 633 | ret = -EINVAL; |
| 634 | goto arg_error; |
| 635 | } |
| 636 | |
| 637 | ret = lttctl_check_trace(name, 1); |
| 638 | if (ret) |
| 639 | goto arg_error; |
| 640 | |
| 641 | if (strcmp(channel, "all")) { |
| 642 | ret = __lttctl_set_channel_subbuf_size(name, channel, |
| 643 | subbuf_size); |
| 644 | if (ret) |
| 645 | goto op_err; |
| 646 | } else { |
| 647 | char **channellist; |
| 648 | int n_channel; |
| 649 | |
| 650 | /* allow set subbuf_size for metadata channel */ |
| 651 | n_channel = lttctl_get_channellist(name, &channellist, 1); |
| 652 | if (n_channel < 0) { |
| 653 | fprintf(stderr, "%s: lttctl_get_channellist failed\n", |
| 654 | __func__); |
| 655 | ret = -ENOENT; |
| 656 | goto op_err; |
| 657 | } |
| 658 | |
| 659 | for (; n_channel > 0; n_channel--) { |
| 660 | ret = __lttctl_set_channel_subbuf_size(name, |
| 661 | channellist[n_channel - 1], subbuf_size); |
| 662 | if (ret) |
| 663 | goto op_err; |
| 664 | } |
| 665 | free(channellist); |
| 666 | } |
| 667 | |
| 668 | return 0; |
| 669 | |
| 670 | op_err: |
| 671 | arg_error: |
| 672 | return ret; |
| 673 | } |
| 674 | |
| 675 | int getdebugfsmntdir(char *mntdir) |
| 676 | { |
| 677 | char mnt_dir[PATH_MAX]; |
| 678 | char mnt_type[PATH_MAX]; |
| 679 | int trymount_done = 0; |
| 680 | |
| 681 | FILE *fp = fopen("/proc/mounts", "r"); |
| 682 | if (!fp) |
| 683 | return -EINVAL; |
| 684 | |
| 685 | find_again: |
| 686 | while (1) { |
| 687 | if (fscanf(fp, "%*s %s %s %*s %*s %*s", mnt_dir, mnt_type) <= 0) |
| 688 | break; |
| 689 | |
| 690 | if (!strcmp(mnt_type, "debugfs")) { |
| 691 | strcpy(mntdir, mnt_dir); |
| 692 | return 0; |
| 693 | } |
| 694 | } |
| 695 | |
| 696 | if (!trymount_done) { |
| 697 | mount("debugfs", "/sys/kernel/debug/", "debugfs", 0, NULL); |
| 698 | trymount_done = 1; |
| 699 | goto find_again; |
| 700 | } |
| 701 | |
| 702 | return -ENOENT; |
| 703 | } |