src/common/runas.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11 #include <errno.h>
  12 #include <limits.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/wait.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <unistd.h>
  20 #include <fcntl.h>
  21 #include <sched.h>
  22 #include <signal.h>
  23 #include <assert.h>
  24 #include <signal.h>
  25
  26 #include <common/lttng-kernel.h>
  27 #include <common/common.h>
  28 #include <common/utils.h>
  29 #include <common/compat/getenv.h>
  30 #include <common/compat/prctl.h>
  31 #include <common/unix.h>
  32 #include <common/defaults.h>
  33 #include <common/lttng-elf.h>
  34
  35 #include <lttng/constant.h>
  36
  37 #include "runas.h"
  38
  39 struct run_as_data;
  40 struct run_as_ret;
  41 typedef int (*run_as_fct)(struct run_as_data *data, struct run_as_ret *ret_value);
  42
  43 enum run_as_cmd {
  44         RUN_AS_MKDIR,
  45         RUN_AS_MKDIRAT,
  46         RUN_AS_MKDIR_RECURSIVE,
  47         RUN_AS_MKDIRAT_RECURSIVE,
  48         RUN_AS_OPEN,
  49         RUN_AS_OPENAT,
  50         RUN_AS_UNLINK,
  51         RUN_AS_UNLINKAT,
  52         RUN_AS_RMDIR,
  53         RUN_AS_RMDIRAT,
  54         RUN_AS_RMDIR_RECURSIVE,
  55         RUN_AS_RMDIRAT_RECURSIVE,
  56         RUN_AS_RENAME,
  57         RUN_AS_RENAMEAT,
  58         RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET,
  59         RUN_AS_EXTRACT_SDT_PROBE_OFFSETS,
  60 };
  61
  62 struct run_as_mkdir_data {
  63         int dirfd;
  64         char path[LTTNG_PATH_MAX];
  65         mode_t mode;
  66 } LTTNG_PACKED;
  67
  68 struct run_as_open_data {
  69         int dirfd;
  70         char path[LTTNG_PATH_MAX];
  71         int flags;
  72         mode_t mode;
  73 } LTTNG_PACKED;
  74
  75 struct run_as_unlink_data {
  76         int dirfd;
  77         char path[LTTNG_PATH_MAX];
  78 } LTTNG_PACKED;
  79
  80 struct run_as_rmdir_data {
  81         int dirfd;
  82         char path[LTTNG_PATH_MAX];
  83         int flags; /* enum lttng_directory_handle_rmdir_recursive_flags */
  84 } LTTNG_PACKED;
  85
  86 struct run_as_extract_elf_symbol_offset_data {
  87         int fd;
  88         char function[LTTNG_SYMBOL_NAME_LEN];
  89 } LTTNG_PACKED;
  90
  91 struct run_as_extract_sdt_probe_offsets_data {
  92         int fd;
  93         char probe_name[LTTNG_SYMBOL_NAME_LEN];
  94         char provider_name[LTTNG_SYMBOL_NAME_LEN];
  95 } LTTNG_PACKED;
  96
  97 struct run_as_rename_data {
  98         /*
  99          * [0] = old_dirfd
 100          * [1] = new_dirfd
 101          */
 102         int dirfds[2];
 103         char old_path[LTTNG_PATH_MAX];
 104         char new_path[LTTNG_PATH_MAX];
 105 } LTTNG_PACKED;
 106
 107 struct run_as_open_ret {
 108         int fd;
 109 } LTTNG_PACKED;
 110
 111 struct run_as_extract_elf_symbol_offset_ret {
 112         uint64_t offset;
 113 } LTTNG_PACKED;
 114
 115 struct run_as_extract_sdt_probe_offsets_ret {
 116         uint32_t num_offset;
 117         uint64_t offsets[LTTNG_KERNEL_MAX_UPROBE_NUM];
 118 } LTTNG_PACKED;
 119
 120 struct run_as_data {
 121         enum run_as_cmd cmd;
 122         union {
 123                 struct run_as_mkdir_data mkdir;
 124                 struct run_as_open_data open;
 125                 struct run_as_unlink_data unlink;
 126                 struct run_as_rmdir_data rmdir;
 127                 struct run_as_rename_data rename;
 128                 struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset;
 129                 struct run_as_extract_sdt_probe_offsets_data extract_sdt_probe_offsets;
 130         } u;
 131         uid_t uid;
 132         gid_t gid;
 133 } LTTNG_PACKED;
 134
 135 /*
 136  * The run_as_ret structure holds the returned value and status of the command.
 137  *
 138  * The `u` union field holds the return value of the command; in most cases it
 139  * represents the success or the failure of the command. In more complex
 140  * commands, it holds a computed value.
 141  *
 142  * The _errno field is the errno recorded after the execution of the command.
 143  *
 144  * The _error fields is used the signify that return status of the command. For
 145  * simple commands returning `int` the _error field will be the same as the
 146  * ret_int field. In complex commands, it signify the success or failure of the
 147  * command.
 148  *
 149  */
 150 struct run_as_ret {
 151         union {
 152                 int ret;
 153                 struct run_as_open_ret open;
 154                 struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset;
 155                 struct run_as_extract_sdt_probe_offsets_ret extract_sdt_probe_offsets;
 156         } u;
 157         int _errno;
 158         bool _error;
 159 } LTTNG_PACKED;
 160
 161 #define COMMAND_IN_FDS(data_ptr) ({                                     \
 162         int *fds = NULL;                                                \
 163         if (command_properties[data_ptr->cmd].in_fds_offset != -1) {    \
 164                 fds = (int *) ((char *) data_ptr + command_properties[data_ptr->cmd].in_fds_offset); \
 165         }                                                               \
 166         fds;                                                            \
 167 })
 168
 169 #define COMMAND_OUT_FDS(cmd, ret_ptr) ({                                \
 170         int *fds = NULL;                                                \
 171         if (command_properties[cmd].out_fds_offset != -1) {             \
 172                 fds = (int *) ((char *) ret_ptr + command_properties[cmd].out_fds_offset); \
 173         }                                                               \
 174         fds;                                                            \
 175 })
 176
 177 #define COMMAND_IN_FD_COUNT(data_ptr) ({                \
 178         command_properties[data_ptr->cmd].in_fd_count;  \
 179 })
 180
 181 #define COMMAND_OUT_FD_COUNT(cmd) ({            \
 182         command_properties[cmd].out_fd_count;   \
 183 })
 184
 185 #define COMMAND_USE_CWD_FD(data_ptr) command_properties[data_ptr->cmd].use_cwd_fd
 186
 187 struct run_as_command_properties {
 188         /* Set to -1 when not applicable. */
 189         ptrdiff_t in_fds_offset, out_fds_offset;
 190         unsigned int in_fd_count, out_fd_count;
 191         bool use_cwd_fd;
 192 };
 193
 194 static const struct run_as_command_properties command_properties[] = {
 195         [RUN_AS_MKDIR] = {
 196                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 197                 .in_fd_count = 1,
 198                 .out_fds_offset = -1,
 199                 .out_fd_count = 0,
 200                 .use_cwd_fd = true,
 201         },
 202         [RUN_AS_MKDIRAT] = {
 203                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 204                 .in_fd_count = 1,
 205                 .out_fds_offset = -1,
 206                 .out_fd_count = 0,
 207                 .use_cwd_fd = false,
 208         },
 209         [RUN_AS_MKDIR_RECURSIVE] = {
 210                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 211                 .in_fd_count = 1,
 212                 .out_fds_offset = -1,
 213                 .out_fd_count = 0,
 214                 .use_cwd_fd = true,
 215         },
 216         [RUN_AS_MKDIRAT_RECURSIVE] = {
 217                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 218                 .in_fd_count = 1,
 219                 .out_fds_offset = -1,
 220                 .out_fd_count = 0,
 221                 .use_cwd_fd = false,
 222         },
 223         [RUN_AS_OPEN] = {
 224                 .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd),
 225                 .in_fd_count = 1,
 226                 .out_fds_offset = offsetof(struct run_as_ret, u.open.fd),
 227                 .out_fd_count = 1,
 228                 .use_cwd_fd = true,
 229         },
 230         [RUN_AS_OPENAT] = {
 231                 .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd),
 232                 .in_fd_count = 1,
 233                 .out_fds_offset = offsetof(struct run_as_ret, u.open.fd),
 234                 .out_fd_count = 1,
 235                 .use_cwd_fd = false,
 236         },
 237         [RUN_AS_UNLINK] = {
 238                 .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd),
 239                 .in_fd_count = 1,
 240                 .out_fds_offset = -1,
 241                 .out_fd_count = 0,
 242                 .use_cwd_fd = true,
 243         },
 244         [RUN_AS_UNLINKAT] = {
 245                 .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd),
 246                 .in_fd_count = 1,
 247                 .out_fds_offset = -1,
 248                 .out_fd_count = 0,
 249                 .use_cwd_fd = false,
 250         },
 251         [RUN_AS_RMDIR_RECURSIVE] = {
 252                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 253                 .in_fd_count = 1,
 254                 .out_fds_offset = -1,
 255                 .out_fd_count = 0,
 256                 .use_cwd_fd = true,
 257         },
 258         [RUN_AS_RMDIRAT_RECURSIVE] = {
 259                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 260                 .in_fd_count = 1,
 261                 .out_fds_offset = -1,
 262                 .out_fd_count = 0,
 263                 .use_cwd_fd = false,
 264         },
 265         [RUN_AS_RMDIR] = {
 266                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 267                 .in_fd_count = 1,
 268                 .out_fds_offset = -1,
 269                 .out_fd_count = 0,
 270                 .use_cwd_fd = true,
 271         },
 272         [RUN_AS_RMDIRAT] = {
 273                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 274                 .in_fd_count = 1,
 275                 .out_fds_offset = -1,
 276                 .out_fd_count = 0,
 277                 .use_cwd_fd = false,
 278         },
 279         [RUN_AS_RENAME] = {
 280                 .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds),
 281                 .in_fd_count = 2,
 282                 .out_fds_offset = -1,
 283                 .out_fd_count = 0,
 284                 .use_cwd_fd = true,
 285         },
 286         [RUN_AS_RENAMEAT] = {
 287                 .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds),
 288                 .in_fd_count = 2,
 289                 .out_fds_offset = -1,
 290                 .out_fd_count = 0,
 291                 .use_cwd_fd = false,
 292         },
 293         [RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET] = {
 294                 .in_fds_offset = offsetof(struct run_as_data,
 295                                 u.extract_elf_symbol_offset.fd),
 296                 .in_fd_count = 1,
 297                 .out_fds_offset = -1,
 298                 .out_fd_count = 0,
 299                 .use_cwd_fd = false,
 300         },
 301         [RUN_AS_EXTRACT_SDT_PROBE_OFFSETS] = {
 302                 .in_fds_offset = offsetof(struct run_as_data,
 303                                 u.extract_sdt_probe_offsets.fd),
 304                 .in_fd_count = 1,
 305                 .out_fds_offset = -1,
 306                 .out_fd_count = 0,
 307                 .use_cwd_fd = false,
 308         },
 309 };
 310
 311 struct run_as_worker {
 312         pid_t pid;      /* Worker PID. */
 313         int sockpair[2];
 314         char *procname;
 315 };
 316
 317 /* Single global worker per process (for now). */
 318 static struct run_as_worker *global_worker;
 319 /* Lock protecting the worker. */
 320 static pthread_mutex_t worker_lock = PTHREAD_MUTEX_INITIALIZER;
 321
 322 #ifdef VALGRIND
 323 static
 324 int use_clone(void)
 325 {
 326         return 0;
 327 }
 328 #else
 329 static
 330 int use_clone(void)
 331 {
 332         return !lttng_secure_getenv("LTTNG_DEBUG_NOCLONE");
 333 }
 334 #endif
 335
 336 /*
 337  * Create recursively directory using the FULL path.
 338  */
 339 static
 340 int _mkdirat_recursive(struct run_as_data *data, struct run_as_ret *ret_value)
 341 {
 342         const char *path;
 343         mode_t mode;
 344         struct lttng_directory_handle *handle;
 345
 346         path = data->u.mkdir.path;
 347         mode = data->u.mkdir.mode;
 348
 349         handle = lttng_directory_handle_create_from_dirfd(data->u.mkdir.dirfd);
 350         if (!handle) {
 351                 ret_value->_errno = errno;
 352                 ret_value->_error = true;
 353                 ret_value->u.ret = -1;
 354                 goto end;
 355         }
 356         /* Ownership of dirfd is transferred to the handle. */
 357         data->u.mkdir.dirfd = -1;
 358         /* Safe to call as we have transitioned to the requested uid/gid. */
 359         ret_value->u.ret = lttng_directory_handle_create_subdirectory_recursive(
 360                         handle, path, mode);
 361         ret_value->_errno = errno;
 362         ret_value->_error = (ret_value->u.ret) ? true : false;
 363         lttng_directory_handle_put(handle);
 364 end:
 365         return ret_value->u.ret;
 366 }
 367
 368 static
 369 int _mkdirat(struct run_as_data *data, struct run_as_ret *ret_value)
 370 {
 371         const char *path;
 372         mode_t mode;
 373         struct lttng_directory_handle *handle;
 374
 375         path = data->u.mkdir.path;
 376         mode = data->u.mkdir.mode;
 377
 378         handle = lttng_directory_handle_create_from_dirfd(data->u.mkdir.dirfd);
 379         if (!handle) {
 380                 ret_value->u.ret = -1;
 381                 ret_value->_errno = errno;
 382                 ret_value->_error = true;
 383                 goto end;
 384         }
 385         /* Ownership of dirfd is transferred to the handle. */
 386         data->u.mkdir.dirfd = -1;
 387         /* Safe to call as we have transitioned to the requested uid/gid. */
 388         ret_value->u.ret = lttng_directory_handle_create_subdirectory(
 389                         handle, path, mode);
 390         ret_value->_errno = errno;
 391         ret_value->_error = (ret_value->u.ret) ? true : false;
 392         lttng_directory_handle_put(handle);
 393 end:
 394         return ret_value->u.ret;
 395 }
 396
 397 static
 398 int _open(struct run_as_data *data, struct run_as_ret *ret_value)
 399 {
 400         int fd;
 401         struct lttng_directory_handle *handle;
 402
 403         handle = lttng_directory_handle_create_from_dirfd(data->u.open.dirfd);
 404         if (!handle) {
 405                 ret_value->_errno = errno;
 406                 ret_value->_error = true;
 407                 ret_value->u.ret = -1;
 408                 goto end;
 409         }
 410         /* Ownership of dirfd is transferred to the handle. */
 411         data->u.open.dirfd = -1;
 412
 413         fd = lttng_directory_handle_open_file(handle,
 414                         data->u.open.path, data->u.open.flags,
 415                         data->u.open.mode);
 416         if (fd < 0) {
 417                 ret_value->u.ret = -1;
 418                 ret_value->u.open.fd = -1;
 419         } else {
 420                 ret_value->u.ret = 0;
 421                 ret_value->u.open.fd = fd;
 422         }
 423
 424         ret_value->_errno = errno;
 425         ret_value->_error = fd < 0;
 426         lttng_directory_handle_put(handle);
 427 end:
 428         return ret_value->u.ret;
 429 }
 430
 431 static
 432 int _unlink(struct run_as_data *data, struct run_as_ret *ret_value)
 433 {
 434         struct lttng_directory_handle *handle;
 435
 436         handle = lttng_directory_handle_create_from_dirfd(data->u.unlink.dirfd);
 437         if (!handle) {
 438                 ret_value->u.ret = -1;
 439                 ret_value->_errno = errno;
 440                 ret_value->_error = true;
 441                 goto end;
 442         }
 443
 444         /* Ownership of dirfd is transferred to the handle. */
 445         data->u.unlink.dirfd = -1;
 446
 447         ret_value->u.ret = lttng_directory_handle_unlink_file(handle,
 448                         data->u.unlink.path);
 449         ret_value->_errno = errno;
 450         ret_value->_error = (ret_value->u.ret) ? true : false;
 451         lttng_directory_handle_put(handle);
 452 end:
 453         return ret_value->u.ret;
 454 }
 455
 456 static
 457 int _rmdir(struct run_as_data *data, struct run_as_ret *ret_value)
 458 {
 459         struct lttng_directory_handle *handle;
 460
 461         handle = lttng_directory_handle_create_from_dirfd(data->u.rmdir.dirfd);
 462         if (!handle) {
 463                 ret_value->u.ret = -1;
 464                 ret_value->_errno = errno;
 465                 ret_value->_error = true;
 466                 goto end;
 467         }
 468
 469         /* Ownership of dirfd is transferred to the handle. */
 470         data->u.rmdir.dirfd = -1;
 471
 472         ret_value->u.ret = lttng_directory_handle_remove_subdirectory(
 473                         handle, data->u.rmdir.path);
 474         ret_value->_errno = errno;
 475         ret_value->_error = (ret_value->u.ret) ? true : false;
 476         lttng_directory_handle_put(handle);
 477 end:
 478         return ret_value->u.ret;
 479 }
 480
 481 static
 482 int _rmdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value)
 483 {
 484         struct lttng_directory_handle *handle;
 485
 486         handle = lttng_directory_handle_create_from_dirfd(data->u.rmdir.dirfd);
 487         if (!handle) {
 488                 ret_value->u.ret = -1;
 489                 ret_value->_errno = errno;
 490                 ret_value->_error = true;
 491                 goto end;
 492         }
 493
 494         /* Ownership of dirfd is transferred to the handle. */
 495         data->u.rmdir.dirfd = -1;
 496
 497         ret_value->u.ret = lttng_directory_handle_remove_subdirectory_recursive(
 498                         handle, data->u.rmdir.path, data->u.rmdir.flags);
 499         ret_value->_errno = errno;
 500         ret_value->_error = (ret_value->u.ret) ? true : false;
 501         lttng_directory_handle_put(handle);
 502 end:
 503         return ret_value->u.ret;
 504 }
 505
 506 static
 507 int _rename(struct run_as_data *data, struct run_as_ret *ret_value)
 508 {
 509         const char *old_path, *new_path;
 510         struct lttng_directory_handle *old_handle = NULL, *new_handle = NULL;
 511
 512         old_path = data->u.rename.old_path;
 513         new_path = data->u.rename.new_path;
 514
 515         old_handle = lttng_directory_handle_create_from_dirfd(
 516                         data->u.rename.dirfds[0]);
 517         if (!old_handle) {
 518                 ret_value->u.ret = -1;
 519                 goto end;
 520         }
 521         new_handle = lttng_directory_handle_create_from_dirfd(
 522                         data->u.rename.dirfds[1]);
 523         if (!new_handle) {
 524                 ret_value->u.ret = -1;
 525                 goto end;
 526         }
 527
 528         /* Ownership of dirfds are transferred to the handles. */
 529         data->u.rename.dirfds[0] = data->u.rename.dirfds[1] = -1;
 530
 531         /* Safe to call as we have transitioned to the requested uid/gid. */
 532         ret_value->u.ret = lttng_directory_handle_rename(
 533                         old_handle, old_path, new_handle, new_path);
 534 end:
 535         lttng_directory_handle_put(old_handle);
 536         lttng_directory_handle_put(new_handle);
 537         ret_value->_errno = errno;
 538         ret_value->_error = (ret_value->u.ret) ? true : false;
 539         return ret_value->u.ret;
 540 }
 541
 542 #ifdef HAVE_ELF_H
 543 static
 544 int _extract_elf_symbol_offset(struct run_as_data *data,
 545                 struct run_as_ret *ret_value)
 546 {
 547         int ret = 0;
 548         uint64_t offset;
 549
 550         ret_value->_error = false;
 551         ret = lttng_elf_get_symbol_offset(data->u.extract_elf_symbol_offset.fd,
 552                          data->u.extract_elf_symbol_offset.function,
 553                          &offset);
 554         if (ret) {
 555                 DBG("Failed to extract ELF function offset");
 556                 ret_value->_error = true;
 557         }
 558         ret_value->u.extract_elf_symbol_offset.offset = offset;
 559
 560         return ret;
 561 }
 562
 563 static
 564 int _extract_sdt_probe_offsets(struct run_as_data *data,
 565                 struct run_as_ret *ret_value)
 566 {
 567         int ret = 0;
 568         uint64_t *offsets = NULL;
 569         uint32_t num_offset;
 570
 571         ret_value->_error = false;
 572
 573         /* On success, this call allocates the offsets paramater. */
 574         ret = lttng_elf_get_sdt_probe_offsets(
 575                         data->u.extract_sdt_probe_offsets.fd,
 576                         data->u.extract_sdt_probe_offsets.provider_name,
 577                         data->u.extract_sdt_probe_offsets.probe_name,
 578                         &offsets, &num_offset);
 579
 580         if (ret) {
 581                 DBG("Failed to extract SDT probe offsets");
 582                 ret_value->_error = true;
 583                 goto end;
 584         }
 585
 586         if (num_offset <= 0 || num_offset > LTTNG_KERNEL_MAX_UPROBE_NUM) {
 587                 DBG("Wrong number of probes.");
 588                 ret = -1;
 589                 ret_value->_error = true;
 590                 goto free_offset;
 591         }
 592
 593         /* Copy the content of the offsets array to the ret struct. */
 594         memcpy(ret_value->u.extract_sdt_probe_offsets.offsets,
 595                         offsets, num_offset * sizeof(uint64_t));
 596
 597         ret_value->u.extract_sdt_probe_offsets.num_offset = num_offset;
 598
 599 free_offset:
 600         free(offsets);
 601 end:
 602         return ret;
 603 }
 604 #else
 605 static
 606 int _extract_elf_symbol_offset(struct run_as_data *data,
 607                 struct run_as_ret *ret_value)
 608 {
 609         ERR("Unimplemented runas command RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET");
 610         return -1;
 611 }
 612
 613 static
 614 int _extract_sdt_probe_offsets(struct run_as_data *data,
 615                 struct run_as_ret *ret_value)
 616 {
 617         ERR("Unimplemented runas command RUN_AS_EXTRACT_SDT_PROBE_OFFSETS");
 618         return -1;
 619 }
 620 #endif
 621
 622 static
 623 run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd)
 624 {
 625         switch (cmd) {
 626         case RUN_AS_MKDIR:
 627         case RUN_AS_MKDIRAT:
 628                 return _mkdirat;
 629         case RUN_AS_MKDIR_RECURSIVE:
 630         case RUN_AS_MKDIRAT_RECURSIVE:
 631                 return _mkdirat_recursive;
 632         case RUN_AS_OPEN:
 633         case RUN_AS_OPENAT:
 634                 return _open;
 635         case RUN_AS_UNLINK:
 636         case RUN_AS_UNLINKAT:
 637                 return _unlink;
 638         case RUN_AS_RMDIR:
 639         case RUN_AS_RMDIRAT:
 640                 return _rmdir;
 641         case RUN_AS_RMDIR_RECURSIVE:
 642         case RUN_AS_RMDIRAT_RECURSIVE:
 643                 return _rmdir_recursive;
 644         case RUN_AS_RENAME:
 645         case RUN_AS_RENAMEAT:
 646                 return _rename;
 647         case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
 648                 return _extract_elf_symbol_offset;
 649         case RUN_AS_EXTRACT_SDT_PROBE_OFFSETS:
 650                 return _extract_sdt_probe_offsets;
 651         default:
 652                 ERR("Unknown command %d", (int) cmd);
 653                 return NULL;
 654         }
 655 }
 656
 657 static
 658 int do_send_fds(int sock, const int *fds, unsigned int fd_count)
 659 {
 660         ssize_t len;
 661         unsigned int i;
 662
 663         for (i = 0; i < fd_count; i++) {
 664                 if (fds[i] < 0) {
 665                         ERR("Attempt to send invalid file descriptor to master (fd = %i)",
 666                                         fds[i]);
 667                         /* Return 0 as this is not a fatal error. */
 668                         return 0;
 669                 }
 670         }
 671
 672         len = lttcomm_send_fds_unix_sock(sock, fds, fd_count);
 673         return len < 0 ? -1 : 0;
 674 }
 675
 676 static
 677 int do_recv_fds(int sock, int *fds, unsigned int fd_count)
 678 {
 679         int ret = 0;
 680         unsigned int i;
 681         ssize_t len;
 682
 683         len = lttcomm_recv_fds_unix_sock(sock, fds, fd_count);
 684         if (len == 0) {
 685                 ret = -1;
 686                 goto end;
 687         } else if (len < 0) {
 688                 PERROR("Failed to receive file descriptors from socket");
 689                 ret = -1;
 690                 goto end;
 691         }
 692
 693         for (i = 0; i < fd_count; i++) {
 694                 if (fds[i] < 0) {
 695                         ERR("Invalid file descriptor received from worker (fd = %i)", fds[i]);
 696                         /* Return 0 as this is not a fatal error. */
 697                 }
 698         }
 699 end:
 700         return ret;
 701 }
 702
 703 static
 704 int send_fds_to_worker(const struct run_as_worker *worker,
 705                 const struct run_as_data *data)
 706 {
 707         int ret = 0;
 708         unsigned int i;
 709
 710         if (COMMAND_USE_CWD_FD(data) || COMMAND_IN_FD_COUNT(data) == 0) {
 711                 goto end;
 712         }
 713
 714         for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 715                 if (COMMAND_IN_FDS(data)[i] < 0) {
 716                         ERR("Refusing to send invalid fd to worker (fd = %i)",
 717                                         COMMAND_IN_FDS(data)[i]);
 718                         ret = -1;
 719                         goto end;
 720                 }
 721         }
 722
 723         ret = do_send_fds(worker->sockpair[0], COMMAND_IN_FDS(data),
 724                         COMMAND_IN_FD_COUNT(data));
 725         if (ret < 0) {
 726                 PERROR("Failed to send file descriptor to run-as worker");
 727                 ret = -1;
 728                 goto end;
 729         }
 730 end:
 731         return ret;
 732 }
 733
 734 static
 735 int send_fds_to_master(struct run_as_worker *worker, enum run_as_cmd cmd,
 736                 struct run_as_ret *run_as_ret)
 737 {
 738         int ret = 0;
 739         unsigned int i;
 740
 741         if (COMMAND_OUT_FD_COUNT(cmd) == 0) {
 742                 goto end;
 743         }
 744
 745         ret = do_send_fds(worker->sockpair[1], COMMAND_OUT_FDS(cmd, run_as_ret),
 746                         COMMAND_OUT_FD_COUNT(cmd));
 747         if (ret < 0) {
 748                 PERROR("Failed to send file descriptor to master process");
 749                 goto end;
 750         }
 751
 752         for (i = 0; i < COMMAND_OUT_FD_COUNT(cmd); i++) {
 753                 int ret_close = close(COMMAND_OUT_FDS(cmd, run_as_ret)[i]);
 754
 755                 if (ret_close < 0) {
 756                         PERROR("Failed to close result file descriptor");
 757                 }
 758         }
 759 end:
 760         return ret;
 761 }
 762
 763 static
 764 int recv_fds_from_worker(const struct run_as_worker *worker, enum run_as_cmd cmd,
 765                 struct run_as_ret *run_as_ret)
 766 {
 767         int ret = 0;
 768
 769         if (COMMAND_OUT_FD_COUNT(cmd) == 0) {
 770                 goto end;
 771         }
 772
 773         ret = do_recv_fds(worker->sockpair[0], COMMAND_OUT_FDS(cmd, run_as_ret),
 774                         COMMAND_OUT_FD_COUNT(cmd));
 775         if (ret < 0) {
 776                 PERROR("Failed to receive file descriptor from run-as worker");
 777                 ret = -1;
 778         }
 779 end:
 780         return ret;
 781 }
 782
 783 static
 784 int recv_fds_from_master(struct run_as_worker *worker, struct run_as_data *data)
 785 {
 786         int ret = 0;
 787
 788         if (COMMAND_USE_CWD_FD(data)) {
 789                 unsigned int i;
 790
 791                 for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 792                         COMMAND_IN_FDS(data)[i] = AT_FDCWD;
 793                 }
 794                 goto end;
 795         }
 796
 797         ret = do_recv_fds(worker->sockpair[1], COMMAND_IN_FDS(data),
 798                         COMMAND_IN_FD_COUNT(data));
 799         if (ret < 0) {
 800                 PERROR("Failed to receive file descriptors from master process");
 801                 ret = -1;
 802         }
 803 end:
 804         return ret;
 805 }
 806
 807 static
 808 int cleanup_received_fds(struct run_as_data *data)
 809 {
 810         int ret = 0, i;
 811
 812         for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 813                 if (COMMAND_IN_FDS(data)[i] == -1) {
 814                         continue;
 815                 }
 816                 ret = close(COMMAND_IN_FDS(data)[i]);
 817                 if (ret) {
 818                         PERROR("Failed to close file descriptor received fd in run-as worker");
 819                         goto end;
 820                 }
 821         }
 822 end:
 823         return ret;
 824 }
 825
 826 /*
 827  * Return < 0 on error, 0 if OK, 1 on hangup.
 828  */
 829 static
 830 int handle_one_cmd(struct run_as_worker *worker)
 831 {
 832         int ret = 0;
 833         struct run_as_data data = {};
 834         ssize_t readlen, writelen;
 835         struct run_as_ret sendret = {};
 836         run_as_fct cmd;
 837         uid_t prev_euid;
 838
 839         /*
 840          * Stage 1: Receive run_as_data struct from the master.
 841          * The structure contains the command type and all the parameters needed for
 842          * its execution
 843          */
 844         readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data,
 845                         sizeof(data));
 846         if (readlen == 0) {
 847                 /* hang up */
 848                 ret = 1;
 849                 goto end;
 850         }
 851         if (readlen < sizeof(data)) {
 852                 PERROR("lttcomm_recv_unix_sock error");
 853                 ret = -1;
 854                 goto end;
 855         }
 856
 857         cmd = run_as_enum_to_fct(data.cmd);
 858         if (!cmd) {
 859                 ret = -1;
 860                 goto end;
 861         }
 862
 863         /*
 864          * Stage 2: Receive file descriptor from master.
 865          * Some commands need a file descriptor as input so if it's needed we
 866          * receive the fd using the Unix socket.
 867          */
 868         ret = recv_fds_from_master(worker, &data);
 869         if (ret < 0) {
 870                 PERROR("recv_fd_from_master error");
 871                 ret = -1;
 872                 goto end;
 873         }
 874
 875         prev_euid = getuid();
 876         if (data.gid != getegid()) {
 877                 ret = setegid(data.gid);
 878                 if (ret < 0) {
 879                         sendret._error = true;
 880                         sendret._errno = errno;
 881                         PERROR("setegid");
 882                         goto write_return;
 883                 }
 884         }
 885         if (data.uid != prev_euid) {
 886                 ret = seteuid(data.uid);
 887                 if (ret < 0) {
 888                         sendret._error = true;
 889                         sendret._errno = errno;
 890                         PERROR("seteuid");
 891                         goto write_return;
 892                 }
 893         }
 894
 895         /*
 896          * Also set umask to 0 for mkdir executable bit.
 897          */
 898         umask(0);
 899
 900         /*
 901          * Stage 3: Execute the command
 902          */
 903         ret = (*cmd)(&data, &sendret);
 904         if (ret < 0) {
 905                 DBG("Execution of command returned an error");
 906         }
 907
 908 write_return:
 909         ret = cleanup_received_fds(&data);
 910         if (ret < 0) {
 911                 ERR("Error cleaning up FD");
 912                 goto end;
 913         }
 914
 915         /*
 916          * Stage 4: Send run_as_ret structure to the master.
 917          * This structure contain the return value of the command and the errno.
 918          */
 919         writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
 920                         sizeof(sendret));
 921         if (writelen < sizeof(sendret)) {
 922                 PERROR("lttcomm_send_unix_sock error");
 923                 ret = -1;
 924                 goto end;
 925         }
 926
 927         /*
 928          * Stage 5: Send resulting file descriptors to the master.
 929          */
 930         ret = send_fds_to_master(worker, data.cmd, &sendret);
 931         if (ret < 0) {
 932                 DBG("Sending FD to master returned an error");
 933                 goto end;
 934         }
 935
 936         if (seteuid(prev_euid) < 0) {
 937                 PERROR("seteuid");
 938                 ret = -1;
 939                 goto end;
 940         }
 941         ret = 0;
 942 end:
 943         return ret;
 944 }
 945
 946 static
 947 int run_as_worker(struct run_as_worker *worker)
 948 {
 949         int ret;
 950         ssize_t writelen;
 951         struct run_as_ret sendret;
 952         size_t proc_orig_len;
 953
 954         /*
 955          * Initialize worker. Set a different process cmdline.
 956          */
 957         proc_orig_len = strlen(worker->procname);
 958         memset(worker->procname, 0, proc_orig_len);
 959         strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len);
 960
 961         ret = lttng_prctl(PR_SET_NAME,
 962                         (unsigned long) DEFAULT_RUN_AS_WORKER_NAME, 0, 0, 0);
 963         if (ret && ret != -ENOSYS) {
 964                 /* Don't fail as this is not essential. */
 965                 PERROR("prctl PR_SET_NAME");
 966         }
 967
 968         memset(&sendret, 0, sizeof(sendret));
 969
 970         writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
 971                         sizeof(sendret));
 972         if (writelen < sizeof(sendret)) {
 973                 PERROR("lttcomm_send_unix_sock error");
 974                 ret = EXIT_FAILURE;
 975                 goto end;
 976         }
 977
 978         for (;;) {
 979                 ret = handle_one_cmd(worker);
 980                 if (ret < 0) {
 981                         ret = EXIT_FAILURE;
 982                         goto end;
 983                 } else if (ret > 0) {
 984                         break;
 985                 } else {
 986                         continue;       /* Next command. */
 987                 }
 988         }
 989         ret = EXIT_SUCCESS;
 990 end:
 991         return ret;
 992 }
 993
 994 static
 995 int run_as_cmd(struct run_as_worker *worker,
 996                 enum run_as_cmd cmd,
 997                 struct run_as_data *data,
 998                 struct run_as_ret *ret_value,
 999                 uid_t uid, gid_t gid)
1000 {
1001         int ret = 0;
1002         ssize_t readlen, writelen;
1003
1004         /*
1005          * If we are non-root, we can only deal with our own uid.
1006          */
1007         if (geteuid() != 0) {
1008                 if (uid != geteuid()) {
1009                         ret = -1;
1010                         ret_value->_errno = EPERM;
1011                         ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
1012                                 (int) uid, (int) geteuid());
1013                         goto end;
1014                 }
1015         }
1016
1017         data->cmd = cmd;
1018         data->uid = uid;
1019         data->gid = gid;
1020
1021         /*
1022          * Stage 1: Send the run_as_data struct to the worker process
1023          */
1024         writelen = lttcomm_send_unix_sock(worker->sockpair[0], data,
1025                         sizeof(*data));
1026         if (writelen < sizeof(*data)) {
1027                 PERROR("Error writing message to run_as");
1028                 ret = -1;
1029                 ret_value->_errno = EIO;
1030                 goto end;
1031         }
1032
1033         /*
1034          * Stage 2: Send file descriptor to the worker process if needed
1035          */
1036         ret = send_fds_to_worker(worker, data);
1037         if (ret) {
1038                 PERROR("do_send_fd error");
1039                 ret = -1;
1040                 ret_value->_errno = EIO;
1041                 goto end;
1042         }
1043
1044         /*
1045          * Stage 3: Wait for the execution of the command
1046          */
1047
1048         /*
1049          * Stage 4: Receive the run_as_ret struct containing the return value and
1050          * errno
1051          */
1052         readlen = lttcomm_recv_unix_sock(worker->sockpair[0], ret_value,
1053                         sizeof(*ret_value));
1054         if (!readlen) {
1055                 ERR("Run-as worker has hung-up during run_as_cmd");
1056                 ret = -1;
1057                 ret_value->_errno = EIO;
1058                 goto end;
1059         } else if (readlen < sizeof(*ret_value)) {
1060                 PERROR("Error reading response from run_as");
1061                 ret = -1;
1062                 ret_value->_errno = errno;
1063                 goto end;
1064         }
1065
1066         if (ret_value->_error) {
1067                 /* Skip stage 5 on error as there will be no fd to receive. */
1068                 goto end;
1069         }
1070
1071         /*
1072          * Stage 5: Receive file descriptor if needed
1073          */
1074         ret = recv_fds_from_worker(worker, cmd, ret_value);
1075         if (ret < 0) {
1076                 ERR("Error receiving fd");
1077                 ret = -1;
1078                 ret_value->_errno = EIO;
1079         }
1080
1081 end:
1082         return ret;
1083 }
1084
1085 /*
1086  * This is for debugging ONLY and should not be considered secure.
1087  */
1088 static
1089 int run_as_noworker(enum run_as_cmd cmd,
1090                 struct run_as_data *data, struct run_as_ret *ret_value,
1091                 uid_t uid, gid_t gid)
1092 {
1093         int ret, saved_errno;
1094         mode_t old_mask;
1095         run_as_fct fct;
1096
1097         fct = run_as_enum_to_fct(cmd);
1098         if (!fct) {
1099                 errno = -ENOSYS;
1100                 ret = -1;
1101                 goto end;
1102         }
1103         old_mask = umask(0);
1104         ret = fct(data, ret_value);
1105         saved_errno = ret_value->_errno;
1106         umask(old_mask);
1107         errno = saved_errno;
1108 end:
1109         return ret;
1110 }
1111
1112 static
1113 int reset_sighandler(void)
1114 {
1115         int sig;
1116
1117         DBG("Resetting run_as worker signal handlers to default");
1118         for (sig = 1; sig <= 31; sig++) {
1119                 (void) signal(sig, SIG_DFL);
1120         }
1121         return 0;
1122 }
1123
1124 static
1125 void worker_sighandler(int sig)
1126 {
1127         const char *signame;
1128
1129         /*
1130          * The worker will inherit its parent's signals since they are part of
1131          * the same process group. However, in the case of SIGINT and SIGTERM,
1132          * we want to give the worker a chance to teardown gracefully when its
1133          * parent closes the command socket.
1134          */
1135         switch (sig) {
1136         case SIGINT:
1137                 signame = "SIGINT";
1138                 break;
1139         case SIGTERM:
1140                 signame = "SIGTERM";
1141                 break;
1142         default:
1143                 signame = NULL;
1144         }
1145
1146         if (signame) {
1147                 DBG("run_as worker received signal %s", signame);
1148         } else {
1149                 DBG("run_as_worker received signal %d", sig);
1150         }
1151 }
1152
1153 static
1154 int set_worker_sighandlers(void)
1155 {
1156         int ret = 0;
1157         sigset_t sigset;
1158         struct sigaction sa;
1159
1160         if ((ret = sigemptyset(&sigset)) < 0) {
1161                 PERROR("sigemptyset");
1162                 goto end;
1163         }
1164
1165         sa.sa_handler = worker_sighandler;
1166         sa.sa_mask = sigset;
1167         sa.sa_flags = 0;
1168         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
1169                 PERROR("sigaction SIGINT");
1170                 goto end;
1171         }
1172
1173         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
1174                 PERROR("sigaction SIGTERM");
1175                 goto end;
1176         }
1177
1178         DBG("run_as signal handler set for SIGTERM and SIGINT");
1179 end:
1180         return ret;
1181 }
1182
1183 static
1184 int run_as_create_worker_no_lock(const char *procname,
1185                 post_fork_cleanup_cb clean_up_func,
1186                 void *clean_up_user_data)
1187 {
1188         pid_t pid;
1189         int i, ret = 0;
1190         ssize_t readlen;
1191         struct run_as_ret recvret;
1192         struct run_as_worker *worker;
1193
1194         assert(!global_worker);
1195         if (!use_clone()) {
1196                 /*
1197                  * Don't initialize a worker, all run_as tasks will be performed
1198                  * in the current process.
1199                  */
1200                 ret = 0;
1201                 goto end;
1202         }
1203         worker = zmalloc(sizeof(*worker));
1204         if (!worker) {
1205                 ret = -ENOMEM;
1206                 goto end;
1207         }
1208         worker->procname = strdup(procname);
1209         if (!worker->procname) {
1210                 ret = -ENOMEM;
1211                 goto error_procname_alloc;
1212         }
1213         /* Create unix socket. */
1214         if (lttcomm_create_anon_unix_socketpair(worker->sockpair) < 0) {
1215                 ret = -1;
1216                 goto error_sock;
1217         }
1218
1219         /* Fork worker. */
1220         pid = fork();
1221         if (pid < 0) {
1222                 PERROR("fork");
1223                 ret = -1;
1224                 goto error_fork;
1225         } else if (pid == 0) {
1226                 /* Child */
1227
1228                 reset_sighandler();
1229
1230                 set_worker_sighandlers();
1231                 if (clean_up_func) {
1232                         if (clean_up_func(clean_up_user_data) < 0) {
1233                                 ERR("Run-as post-fork clean-up failed, exiting.");
1234                                 exit(EXIT_FAILURE);
1235                         }
1236                 }
1237
1238                 /* Just close, no shutdown. */
1239                 if (close(worker->sockpair[0])) {
1240                         PERROR("close");
1241                         exit(EXIT_FAILURE);
1242                 }
1243
1244                 /*
1245                  * Close all FDs aside from STDIN, STDOUT, STDERR and sockpair[1]
1246                  * Sockpair[1] is used as a control channel with the master
1247                  */
1248                 for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
1249                         if (i != worker->sockpair[1]) {
1250                                 (void) close(i);
1251                         }
1252                 }
1253
1254                 worker->sockpair[0] = -1;
1255                 ret = run_as_worker(worker);
1256                 if (lttcomm_close_unix_sock(worker->sockpair[1])) {
1257                         PERROR("close");
1258                         ret = -1;
1259                 }
1260                 worker->sockpair[1] = -1;
1261                 free(worker->procname);
1262                 free(worker);
1263                 LOG(ret ? PRINT_ERR : PRINT_DBG, "run_as worker exiting (ret = %d)", ret);
1264                 exit(ret ? EXIT_FAILURE : EXIT_SUCCESS);
1265         } else {
1266                 /* Parent */
1267
1268                 /* Just close, no shutdown. */
1269                 if (close(worker->sockpair[1])) {
1270                         PERROR("close");
1271                         ret = -1;
1272                         goto error_fork;
1273                 }
1274                 worker->sockpair[1] = -1;
1275                 worker->pid = pid;
1276                 /* Wait for worker to become ready. */
1277                 readlen = lttcomm_recv_unix_sock(worker->sockpair[0],
1278                                 &recvret, sizeof(recvret));
1279                 if (readlen < sizeof(recvret)) {
1280                         ERR("readlen: %zd", readlen);
1281                         PERROR("Error reading response from run_as at creation");
1282                         ret = -1;
1283                         goto error_fork;
1284                 }
1285                 global_worker = worker;
1286         }
1287 end:
1288         return ret;
1289
1290         /* Error handling. */
1291 error_fork:
1292         for (i = 0; i < 2; i++) {
1293                 if (worker->sockpair[i] < 0) {
1294                         continue;
1295                 }
1296                 if (lttcomm_close_unix_sock(worker->sockpair[i])) {
1297                         PERROR("close");
1298                 }
1299                 worker->sockpair[i] = -1;
1300         }
1301 error_sock:
1302         free(worker->procname);
1303 error_procname_alloc:
1304         free(worker);
1305         return ret;
1306 }
1307
1308 static
1309 void run_as_destroy_worker_no_lock(void)
1310 {
1311         struct run_as_worker *worker = global_worker;
1312
1313         DBG("Destroying run_as worker");
1314         if (!worker) {
1315                 return;
1316         }
1317         /* Close unix socket */
1318         DBG("Closing run_as worker socket");
1319         if (lttcomm_close_unix_sock(worker->sockpair[0])) {
1320                 PERROR("close");
1321         }
1322         worker->sockpair[0] = -1;
1323         /* Wait for worker. */
1324         for (;;) {
1325                 int status;
1326                 pid_t wait_ret;
1327
1328                 wait_ret = waitpid(worker->pid, &status, 0);
1329                 if (wait_ret < 0) {
1330                         if (errno == EINTR) {
1331                                 continue;
1332                         }
1333                         PERROR("waitpid");
1334                         break;
1335                 }
1336
1337                 if (WIFEXITED(status)) {
1338                         LOG(WEXITSTATUS(status) == 0 ? PRINT_DBG : PRINT_ERR,
1339                                         DEFAULT_RUN_AS_WORKER_NAME " terminated with status code %d",
1340                                         WEXITSTATUS(status));
1341                         break;
1342                 } else if (WIFSIGNALED(status)) {
1343                         ERR(DEFAULT_RUN_AS_WORKER_NAME " was killed by signal %d",
1344                                         WTERMSIG(status));
1345                         break;
1346                 }
1347         }
1348         free(worker->procname);
1349         free(worker);
1350         global_worker = NULL;
1351 }
1352
1353 static
1354 int run_as_restart_worker(struct run_as_worker *worker)
1355 {
1356         int ret = 0;
1357         char *procname = NULL;
1358
1359         procname = worker->procname;
1360
1361         /* Close socket to run_as worker process and clean up the zombie process */
1362         run_as_destroy_worker_no_lock();
1363
1364         /* Create a new run_as worker process*/
1365         ret = run_as_create_worker_no_lock(procname, NULL, NULL);
1366         if (ret < 0 ) {
1367                 ERR("Restarting the worker process failed");
1368                 ret = -1;
1369                 goto err;
1370         }
1371 err:
1372         return ret;
1373 }
1374
1375 static
1376 int run_as(enum run_as_cmd cmd, struct run_as_data *data,
1377                    struct run_as_ret *ret_value, uid_t uid, gid_t gid)
1378 {
1379         int ret, saved_errno;
1380
1381         pthread_mutex_lock(&worker_lock);
1382         if (use_clone()) {
1383                 DBG("Using run_as worker");
1384
1385                 assert(global_worker);
1386
1387                 ret = run_as_cmd(global_worker, cmd, data, ret_value, uid, gid);
1388                 saved_errno = ret_value->_errno;
1389
1390                 /*
1391                  * If the worker thread crashed the errno is set to EIO. we log
1392                  * the error and  start a new worker process.
1393                  */
1394                 if (ret == -1 && saved_errno == EIO) {
1395                         DBG("Socket closed unexpectedly... "
1396                                         "Restarting the worker process");
1397                         ret = run_as_restart_worker(global_worker);
1398                         if (ret == -1) {
1399                                 ERR("Failed to restart worker process.");
1400                                 goto err;
1401                         }
1402                 }
1403         } else {
1404                 DBG("Using run_as without worker");
1405                 ret = run_as_noworker(cmd, data, ret_value, uid, gid);
1406         }
1407 err:
1408         pthread_mutex_unlock(&worker_lock);
1409         return ret;
1410 }
1411
1412 LTTNG_HIDDEN
1413 int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid)
1414 {
1415         return run_as_mkdirat_recursive(AT_FDCWD, path, mode, uid, gid);
1416 }
1417
1418 LTTNG_HIDDEN
1419 int run_as_mkdirat_recursive(int dirfd, const char *path, mode_t mode,
1420                 uid_t uid, gid_t gid)
1421 {
1422         int ret;
1423         struct run_as_data data = {};
1424         struct run_as_ret run_as_ret = {};
1425
1426         DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d",
1427                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1428                         path, (int) mode, (int) uid, (int) gid);
1429         ret = lttng_strncpy(data.u.mkdir.path, path,
1430                         sizeof(data.u.mkdir.path));
1431         if (ret) {
1432                 ERR("Failed to copy path argument of mkdirat recursive command");
1433                 goto error;
1434         }
1435         data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0';
1436         data.u.mkdir.mode = mode;
1437         data.u.mkdir.dirfd = dirfd;
1438         run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR_RECURSIVE : RUN_AS_MKDIRAT_RECURSIVE,
1439                         &data, &run_as_ret, uid, gid);
1440         errno = run_as_ret._errno;
1441         ret = run_as_ret.u.ret;
1442 error:
1443         return ret;
1444 }
1445
1446 LTTNG_HIDDEN
1447 int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid)
1448 {
1449         return run_as_mkdirat(AT_FDCWD, path, mode, uid, gid);
1450 }
1451
1452 LTTNG_HIDDEN
1453 int run_as_mkdirat(int dirfd, const char *path, mode_t mode,
1454                 uid_t uid, gid_t gid)
1455 {
1456         int ret;
1457         struct run_as_data data = {};
1458         struct run_as_ret run_as_ret = {};
1459
1460         DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d",
1461                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1462                         path, (int) mode, (int) uid, (int) gid);
1463         ret = lttng_strncpy(data.u.mkdir.path, path,
1464                         sizeof(data.u.mkdir.path));
1465         if (ret) {
1466                 ERR("Failed to copy path argument of mkdirat command");
1467                 goto error;
1468         }
1469         data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0';
1470         data.u.mkdir.mode = mode;
1471         data.u.mkdir.dirfd = dirfd;
1472         run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR : RUN_AS_MKDIRAT,
1473                         &data, &run_as_ret, uid, gid);
1474         errno = run_as_ret._errno;
1475         ret = run_as_ret.u.ret;
1476 error:
1477         return ret;
1478 }
1479
1480 LTTNG_HIDDEN
1481 int run_as_open(const char *path, int flags, mode_t mode, uid_t uid,
1482                 gid_t gid)
1483 {
1484         return run_as_openat(AT_FDCWD, path, flags, mode, uid, gid);
1485 }
1486
1487 LTTNG_HIDDEN
1488 int run_as_openat(int dirfd, const char *path, int flags, mode_t mode,
1489                 uid_t uid, gid_t gid)
1490 {
1491         int ret;
1492         struct run_as_data data = {};
1493         struct run_as_ret run_as_ret = {};
1494
1495         DBG3("openat() fd = %d%s, path = %s, flags = %X, mode = %d, uid %d, gid %d",
1496                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1497                         path, flags, (int) mode, (int) uid, (int) gid);
1498         ret = lttng_strncpy(data.u.open.path, path, sizeof(data.u.open.path));
1499         if (ret) {
1500                 ERR("Failed to copy path argument of open command");
1501                 goto error;
1502         }
1503         data.u.open.flags = flags;
1504         data.u.open.mode = mode;
1505         data.u.open.dirfd = dirfd;
1506         run_as(dirfd == AT_FDCWD ? RUN_AS_OPEN : RUN_AS_OPENAT,
1507                         &data, &run_as_ret, uid, gid);
1508         errno = run_as_ret._errno;
1509         ret = run_as_ret.u.ret < 0 ? run_as_ret.u.ret :
1510                         run_as_ret.u.open.fd;
1511 error:
1512         return ret;
1513 }
1514
1515 LTTNG_HIDDEN
1516 int run_as_unlink(const char *path, uid_t uid, gid_t gid)
1517 {
1518         return run_as_unlinkat(AT_FDCWD, path, uid, gid);
1519 }
1520
1521 LTTNG_HIDDEN
1522 int run_as_unlinkat(int dirfd, const char *path, uid_t uid, gid_t gid)
1523 {
1524         int ret;
1525         struct run_as_data data = {};
1526         struct run_as_ret run_as_ret = {};
1527
1528         DBG3("unlinkat() fd = %d%s, path = %s, uid = %d, gid = %d",
1529                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1530                         path, (int) uid, (int) gid);
1531         ret = lttng_strncpy(data.u.unlink.path, path,
1532                         sizeof(data.u.unlink.path));
1533         if (ret) {
1534                 goto error;
1535         }
1536         data.u.unlink.dirfd = dirfd;
1537         run_as(dirfd == AT_FDCWD ? RUN_AS_UNLINK : RUN_AS_UNLINKAT, &data,
1538                         &run_as_ret, uid, gid);
1539         errno = run_as_ret._errno;
1540         ret = run_as_ret.u.ret;
1541 error:
1542         return ret;
1543 }
1544
1545 LTTNG_HIDDEN
1546 int run_as_rmdir(const char *path, uid_t uid, gid_t gid)
1547 {
1548         return run_as_rmdirat(AT_FDCWD, path, uid, gid);
1549 }
1550
1551 LTTNG_HIDDEN
1552 int run_as_rmdirat(int dirfd, const char *path, uid_t uid, gid_t gid)
1553 {
1554         int ret;
1555         struct run_as_data data = {};
1556         struct run_as_ret run_as_ret = {};
1557
1558         DBG3("rmdirat() fd = %d%s, path = %s, uid = %d, gid = %d",
1559                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1560                         path, (int) uid, (int) gid);
1561         ret = lttng_strncpy(data.u.rmdir.path, path,
1562                         sizeof(data.u.rmdir.path));
1563         if (ret) {
1564                 goto error;
1565         }
1566         data.u.rmdir.dirfd = dirfd;
1567         run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR : RUN_AS_RMDIRAT, &data,
1568                         &run_as_ret, uid, gid);
1569         errno = run_as_ret._errno;
1570         ret = run_as_ret.u.ret;
1571 error:
1572         return ret;
1573 }
1574
1575 LTTNG_HIDDEN
1576 int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid, int flags)
1577 {
1578         return run_as_rmdirat_recursive(AT_FDCWD, path, uid, gid, flags);
1579 }
1580
1581 LTTNG_HIDDEN
1582 int run_as_rmdirat_recursive(int dirfd, const char *path, uid_t uid, gid_t gid, int flags)
1583 {
1584         int ret;
1585         struct run_as_data data = {};
1586         struct run_as_ret run_as_ret = {};
1587
1588         DBG3("rmdirat() recursive fd = %d%s, path = %s, uid = %d, gid = %d",
1589                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1590                         path, (int) uid, (int) gid);
1591         ret = lttng_strncpy(data.u.rmdir.path, path,
1592                         sizeof(data.u.rmdir.path));
1593         if (ret) {
1594                 goto error;
1595         }
1596         data.u.rmdir.dirfd = dirfd;
1597         data.u.rmdir.flags = flags;
1598         run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR_RECURSIVE : RUN_AS_RMDIRAT_RECURSIVE,
1599                         &data, &run_as_ret, uid, gid);
1600         errno = run_as_ret._errno;
1601         ret = run_as_ret.u.ret;
1602 error:
1603         return ret;
1604 }
1605
1606 LTTNG_HIDDEN
1607 int run_as_rename(const char *old, const char *new, uid_t uid, gid_t gid)
1608 {
1609         return run_as_renameat(AT_FDCWD, old, AT_FDCWD, new, uid, gid);
1610 }
1611
1612 LTTNG_HIDDEN
1613 int run_as_renameat(int old_dirfd, const char *old_name,
1614                 int new_dirfd, const char *new_name, uid_t uid, gid_t gid)
1615 {
1616         int ret;
1617         struct run_as_data data = {};
1618         struct run_as_ret run_as_ret = {};
1619
1620         DBG3("renameat() old_dirfd = %d%s, old_name = %s, new_dirfd = %d%s, new_name = %s, uid = %d, gid = %d",
1621                         old_dirfd, old_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1622                         old_name,
1623                         new_dirfd, new_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1624                         new_name, (int) uid, (int) gid);
1625         ret = lttng_strncpy(data.u.rename.old_path, old_name,
1626                         sizeof(data.u.rename.old_path));
1627         if (ret) {
1628                 goto error;
1629         }
1630         ret = lttng_strncpy(data.u.rename.new_path, new_name,
1631                         sizeof(data.u.rename.new_path));
1632         if (ret) {
1633                 goto error;
1634         }
1635
1636         data.u.rename.dirfds[0] = old_dirfd;
1637         data.u.rename.dirfds[1] = new_dirfd;
1638         run_as(old_dirfd == AT_FDCWD && new_dirfd == AT_FDCWD ?
1639                         RUN_AS_RENAME : RUN_AS_RENAMEAT,
1640                         &data, &run_as_ret, uid, gid);
1641         errno = run_as_ret._errno;
1642         ret = run_as_ret.u.ret;
1643 error:
1644         return ret;
1645 }
1646
1647 LTTNG_HIDDEN
1648 int run_as_extract_elf_symbol_offset(int fd, const char* function,
1649                 uid_t uid, gid_t gid, uint64_t *offset)
1650 {
1651         int ret;
1652         struct run_as_data data = {};
1653         struct run_as_ret run_as_ret = {};
1654
1655         DBG3("extract_elf_symbol_offset() on fd=%d and function=%s "
1656                         "with for uid %d and gid %d", fd, function,
1657                         (int) uid, (int) gid);
1658
1659         data.u.extract_elf_symbol_offset.fd = fd;
1660
1661         strncpy(data.u.extract_elf_symbol_offset.function, function, LTTNG_SYMBOL_NAME_LEN - 1);
1662         data.u.extract_elf_symbol_offset.function[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
1663         ret = lttng_strncpy(data.u.extract_elf_symbol_offset.function,
1664                         function,
1665                         sizeof(data.u.extract_elf_symbol_offset.function));
1666         if (ret) {
1667                 goto error;
1668         }
1669
1670         run_as(RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, &data, &run_as_ret, uid, gid);
1671         errno = run_as_ret._errno;
1672         if (run_as_ret._error) {
1673                 ret = -1;
1674                 goto error;
1675         }
1676
1677         *offset = run_as_ret.u.extract_elf_symbol_offset.offset;
1678 error:
1679         return ret;
1680 }
1681
1682 LTTNG_HIDDEN
1683 int run_as_extract_sdt_probe_offsets(int fd, const char* provider_name,
1684                 const char* probe_name, uid_t uid, gid_t gid,
1685                 uint64_t **offsets, uint32_t *num_offset)
1686 {
1687         int ret;
1688         struct run_as_data data = {};
1689         struct run_as_ret run_as_ret = {};
1690
1691         DBG3("extract_sdt_probe_offsets() on fd=%d, probe_name=%s and "
1692                         "provider_name=%s with for uid %d and gid %d", fd,
1693                         probe_name, provider_name, (int) uid, (int) gid);
1694
1695         data.u.extract_sdt_probe_offsets.fd = fd;
1696
1697         ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.probe_name, probe_name,
1698                         sizeof(data.u.extract_sdt_probe_offsets.probe_name));
1699         if (ret) {
1700                 goto error;
1701         }
1702         ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.provider_name,
1703                         provider_name,
1704                         sizeof(data.u.extract_sdt_probe_offsets.provider_name));
1705         if (ret) {
1706                 goto error;
1707         }
1708
1709         run_as(RUN_AS_EXTRACT_SDT_PROBE_OFFSETS, &data, &run_as_ret, uid, gid);
1710         errno = run_as_ret._errno;
1711         if (run_as_ret._error) {
1712                 ret = -1;
1713                 goto error;
1714         }
1715
1716         *num_offset = run_as_ret.u.extract_sdt_probe_offsets.num_offset;
1717         *offsets = zmalloc(*num_offset * sizeof(uint64_t));
1718         if (!*offsets) {
1719                 ret = -ENOMEM;
1720                 goto error;
1721         }
1722
1723         memcpy(*offsets, run_as_ret.u.extract_sdt_probe_offsets.offsets,
1724                         *num_offset * sizeof(uint64_t));
1725 error:
1726         return ret;
1727 }
1728
1729 LTTNG_HIDDEN
1730 int run_as_create_worker(const char *procname,
1731                 post_fork_cleanup_cb clean_up_func,
1732                 void *clean_up_user_data)
1733 {
1734         int ret;
1735
1736         pthread_mutex_lock(&worker_lock);
1737         ret = run_as_create_worker_no_lock(procname, clean_up_func,
1738                         clean_up_user_data);
1739         pthread_mutex_unlock(&worker_lock);
1740         return ret;
1741 }
1742
1743 LTTNG_HIDDEN
1744 void run_as_destroy_worker(void)
1745 {
1746         pthread_mutex_lock(&worker_lock);
1747         run_as_destroy_worker_no_lock();
1748         pthread_mutex_unlock(&worker_lock);
1749 }