src/common/runas.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *               2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/wait.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <unistd.h>
  30 #include <fcntl.h>
  31 #include <sched.h>
  32 #include <signal.h>
  33 #include <assert.h>
  34 #include <signal.h>
  35
  36 #include <common/lttng-kernel.h>
  37 #include <common/common.h>
  38 #include <common/utils.h>
  39 #include <common/compat/getenv.h>
  40 #include <common/compat/prctl.h>
  41 #include <common/unix.h>
  42 #include <common/defaults.h>
  43 #include <common/lttng-elf.h>
  44
  45 #include <lttng/constant.h>
  46
  47 #include "runas.h"
  48
  49 struct run_as_data;
  50 struct run_as_ret;
  51 typedef int (*run_as_fct)(struct run_as_data *data, struct run_as_ret *ret_value);
  52
  53 enum run_as_cmd {
  54         RUN_AS_MKDIR,
  55         RUN_AS_MKDIRAT,
  56         RUN_AS_MKDIR_RECURSIVE,
  57         RUN_AS_MKDIRAT_RECURSIVE,
  58         RUN_AS_OPEN,
  59         RUN_AS_OPENAT,
  60         RUN_AS_UNLINK,
  61         RUN_AS_UNLINKAT,
  62         RUN_AS_RMDIR,
  63         RUN_AS_RMDIRAT,
  64         RUN_AS_RMDIR_RECURSIVE,
  65         RUN_AS_RMDIRAT_RECURSIVE,
  66         RUN_AS_RENAME,
  67         RUN_AS_RENAMEAT,
  68         RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET,
  69         RUN_AS_EXTRACT_SDT_PROBE_OFFSETS,
  70 };
  71
  72 struct run_as_mkdir_data {
  73         int dirfd;
  74         char path[LTTNG_PATH_MAX];
  75         mode_t mode;
  76 } LTTNG_PACKED;
  77
  78 struct run_as_open_data {
  79         int dirfd;
  80         char path[LTTNG_PATH_MAX];
  81         int flags;
  82         mode_t mode;
  83 } LTTNG_PACKED;
  84
  85 struct run_as_unlink_data {
  86         int dirfd;
  87         char path[LTTNG_PATH_MAX];
  88 } LTTNG_PACKED;
  89
  90 struct run_as_rmdir_data {
  91         int dirfd;
  92         char path[LTTNG_PATH_MAX];
  93 } LTTNG_PACKED;
  94
  95 struct run_as_extract_elf_symbol_offset_data {
  96         int fd;
  97         char function[LTTNG_SYMBOL_NAME_LEN];
  98 } LTTNG_PACKED;
  99
 100 struct run_as_extract_sdt_probe_offsets_data {
 101         int fd;
 102         char probe_name[LTTNG_SYMBOL_NAME_LEN];
 103         char provider_name[LTTNG_SYMBOL_NAME_LEN];
 104 } LTTNG_PACKED;
 105
 106 struct run_as_rename_data {
 107         /*
 108          * [0] = old_dirfd
 109          * [1] = new_dirfd
 110          */
 111         int dirfds[2];
 112         char old_path[LTTNG_PATH_MAX];
 113         char new_path[LTTNG_PATH_MAX];
 114 } LTTNG_PACKED;
 115
 116 struct run_as_open_ret {
 117         int fd;
 118 } LTTNG_PACKED;
 119
 120 struct run_as_extract_elf_symbol_offset_ret {
 121         uint64_t offset;
 122 } LTTNG_PACKED;
 123
 124 struct run_as_extract_sdt_probe_offsets_ret {
 125         uint32_t num_offset;
 126         uint64_t offsets[LTTNG_KERNEL_MAX_UPROBE_NUM];
 127 } LTTNG_PACKED;
 128
 129 struct run_as_data {
 130         enum run_as_cmd cmd;
 131         union {
 132                 struct run_as_mkdir_data mkdir;
 133                 struct run_as_open_data open;
 134                 struct run_as_unlink_data unlink;
 135                 struct run_as_rmdir_data rmdir;
 136                 struct run_as_rename_data rename;
 137                 struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset;
 138                 struct run_as_extract_sdt_probe_offsets_data extract_sdt_probe_offsets;
 139         } u;
 140         uid_t uid;
 141         gid_t gid;
 142 } LTTNG_PACKED;
 143
 144 /*
 145  * The run_as_ret structure holds the returned value and status of the command.
 146  *
 147  * The `u` union field holds the return value of the command; in most cases it
 148  * represents the success or the failure of the command. In more complex
 149  * commands, it holds a computed value.
 150  *
 151  * The _errno field is the errno recorded after the execution of the command.
 152  *
 153  * The _error fields is used the signify that return status of the command. For
 154  * simple commands returning `int` the _error field will be the same as the
 155  * ret_int field. In complex commands, it signify the success or failure of the
 156  * command.
 157  *
 158  */
 159 struct run_as_ret {
 160         union {
 161                 int ret;
 162                 struct run_as_open_ret open;
 163                 struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset;
 164                 struct run_as_extract_sdt_probe_offsets_ret extract_sdt_probe_offsets;
 165         } u;
 166         int _errno;
 167         bool _error;
 168 } LTTNG_PACKED;
 169
 170 #define COMMAND_IN_FDS(data_ptr) ({                                     \
 171         int *fds = NULL;                                                \
 172         if (command_properties[data_ptr->cmd].in_fds_offset != -1) {    \
 173                 fds = (int *) ((char *) data_ptr + command_properties[data_ptr->cmd].in_fds_offset); \
 174         }                                                               \
 175         fds;                                                            \
 176 })
 177
 178 #define COMMAND_OUT_FDS(cmd, ret_ptr) ({                                \
 179         int *fds = NULL;                                                \
 180         if (command_properties[cmd].out_fds_offset != -1) {             \
 181                 fds = (int *) ((char *) ret_ptr + command_properties[cmd].out_fds_offset); \
 182         }                                                               \
 183         fds;                                                            \
 184 })
 185
 186 #define COMMAND_IN_FD_COUNT(data_ptr) ({                \
 187         command_properties[data_ptr->cmd].in_fd_count;  \
 188 })
 189
 190 #define COMMAND_OUT_FD_COUNT(cmd) ({            \
 191         command_properties[cmd].out_fd_count;   \
 192 })
 193
 194 #define COMMAND_USE_CWD_FD(data_ptr) command_properties[data_ptr->cmd].use_cwd_fd
 195
 196 struct run_as_command_properties {
 197         /* Set to -1 when not applicable. */
 198         ptrdiff_t in_fds_offset, out_fds_offset;
 199         unsigned int in_fd_count, out_fd_count;
 200         bool use_cwd_fd;
 201 };
 202
 203 static const struct run_as_command_properties command_properties[] = {
 204         [RUN_AS_MKDIR] = {
 205                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 206                 .in_fd_count = 1,
 207                 .out_fds_offset = -1,
 208                 .out_fd_count = 0,
 209                 .use_cwd_fd = true,
 210         },
 211         [RUN_AS_MKDIRAT] = {
 212                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 213                 .in_fd_count = 1,
 214                 .out_fds_offset = -1,
 215                 .out_fd_count = 0,
 216                 .use_cwd_fd = false,
 217         },
 218         [RUN_AS_MKDIR_RECURSIVE] = {
 219                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 220                 .in_fd_count = 1,
 221                 .out_fds_offset = -1,
 222                 .out_fd_count = 0,
 223                 .use_cwd_fd = true,
 224         },
 225         [RUN_AS_MKDIRAT_RECURSIVE] = {
 226                 .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd),
 227                 .in_fd_count = 1,
 228                 .out_fds_offset = -1,
 229                 .out_fd_count = 0,
 230                 .use_cwd_fd = false,
 231         },
 232         [RUN_AS_OPEN] = {
 233                 .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd),
 234                 .in_fd_count = 1,
 235                 .out_fds_offset = offsetof(struct run_as_ret, u.open.fd),
 236                 .out_fd_count = 1,
 237                 .use_cwd_fd = true,
 238         },
 239         [RUN_AS_OPENAT] = {
 240                 .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd),
 241                 .in_fd_count = 1,
 242                 .out_fds_offset = offsetof(struct run_as_ret, u.open.fd),
 243                 .out_fd_count = 1,
 244                 .use_cwd_fd = false,
 245         },
 246         [RUN_AS_UNLINK] = {
 247                 .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd),
 248                 .in_fd_count = 1,
 249                 .out_fds_offset = -1,
 250                 .out_fd_count = 0,
 251                 .use_cwd_fd = true,
 252         },
 253         [RUN_AS_UNLINKAT] = {
 254                 .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd),
 255                 .in_fd_count = 1,
 256                 .out_fds_offset = -1,
 257                 .out_fd_count = 0,
 258                 .use_cwd_fd = false,
 259         },
 260         [RUN_AS_RMDIR_RECURSIVE] = {
 261                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 262                 .in_fd_count = 1,
 263                 .out_fds_offset = -1,
 264                 .out_fd_count = 0,
 265                 .use_cwd_fd = true,
 266         },
 267         [RUN_AS_RMDIRAT_RECURSIVE] = {
 268                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 269                 .in_fd_count = 1,
 270                 .out_fds_offset = -1,
 271                 .out_fd_count = 0,
 272                 .use_cwd_fd = false,
 273         },
 274         [RUN_AS_RMDIR] = {
 275                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 276                 .in_fd_count = 1,
 277                 .out_fds_offset = -1,
 278                 .out_fd_count = 0,
 279                 .use_cwd_fd = true,
 280         },
 281         [RUN_AS_RMDIRAT] = {
 282                 .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd),
 283                 .in_fd_count = 1,
 284                 .out_fds_offset = -1,
 285                 .out_fd_count = 0,
 286                 .use_cwd_fd = false,
 287         },
 288         [RUN_AS_RENAME] = {
 289                 .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds),
 290                 .in_fd_count = 2,
 291                 .out_fds_offset = -1,
 292                 .out_fd_count = 0,
 293                 .use_cwd_fd = true,
 294         },
 295         [RUN_AS_RENAMEAT] = {
 296                 .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds),
 297                 .in_fd_count = 2,
 298                 .out_fds_offset = -1,
 299                 .out_fd_count = 0,
 300                 .use_cwd_fd = false,
 301         },
 302         [RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET] = {
 303                 .in_fds_offset = offsetof(struct run_as_data,
 304                                 u.extract_elf_symbol_offset.fd),
 305                 .in_fd_count = 1,
 306                 .out_fds_offset = -1,
 307                 .out_fd_count = 0,
 308                 .use_cwd_fd = false,
 309         },
 310         [RUN_AS_EXTRACT_SDT_PROBE_OFFSETS] = {
 311                 .in_fds_offset = offsetof(struct run_as_data,
 312                                 u.extract_sdt_probe_offsets.fd),
 313                 .in_fd_count = 1,
 314                 .out_fds_offset = -1,
 315                 .out_fd_count = 0,
 316                 .use_cwd_fd = false,
 317         },
 318 };
 319
 320 struct run_as_worker {
 321         pid_t pid;      /* Worker PID. */
 322         int sockpair[2];
 323         char *procname;
 324 };
 325
 326 /* Single global worker per process (for now). */
 327 static struct run_as_worker *global_worker;
 328 /* Lock protecting the worker. */
 329 static pthread_mutex_t worker_lock = PTHREAD_MUTEX_INITIALIZER;
 330
 331 #ifdef VALGRIND
 332 static
 333 int use_clone(void)
 334 {
 335         return 0;
 336 }
 337 #else
 338 static
 339 int use_clone(void)
 340 {
 341         return !lttng_secure_getenv("LTTNG_DEBUG_NOCLONE");
 342 }
 343 #endif
 344
 345 /*
 346  * Create recursively directory using the FULL path.
 347  */
 348 static
 349 int _mkdirat_recursive(struct run_as_data *data, struct run_as_ret *ret_value)
 350 {
 351         const char *path;
 352         mode_t mode;
 353         struct lttng_directory_handle handle;
 354
 355         path = data->u.mkdir.path;
 356         mode = data->u.mkdir.mode;
 357
 358         (void) lttng_directory_handle_init_from_dirfd(&handle,
 359                         data->u.mkdir.dirfd);
 360         /* Ownership of dirfd is transferred to the handle. */
 361         data->u.mkdir.dirfd = -1;
 362         /* Safe to call as we have transitioned to the requested uid/gid. */
 363         ret_value->u.ret =
 364                         lttng_directory_handle_create_subdirectory_recursive(
 365                                         &handle, path, mode);
 366         ret_value->_errno = errno;
 367         ret_value->_error = (ret_value->u.ret) ? true : false;
 368         lttng_directory_handle_fini(&handle);
 369         return ret_value->u.ret;
 370 }
 371
 372 static
 373 int _mkdirat(struct run_as_data *data, struct run_as_ret *ret_value)
 374 {
 375         const char *path;
 376         mode_t mode;
 377         struct lttng_directory_handle handle;
 378
 379         path = data->u.mkdir.path;
 380         mode = data->u.mkdir.mode;
 381
 382         (void) lttng_directory_handle_init_from_dirfd(&handle,
 383                         data->u.mkdir.dirfd);
 384         /* Ownership of dirfd is transferred to the handle. */
 385         data->u.mkdir.dirfd = -1;
 386         /* Safe to call as we have transitioned to the requested uid/gid. */
 387         ret_value->u.ret =
 388                         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_fini(&handle);
 393         return ret_value->u.ret;
 394 }
 395
 396 static
 397 int _open(struct run_as_data *data, struct run_as_ret *ret_value)
 398 {
 399         int fd;
 400         struct lttng_directory_handle handle;
 401
 402         (void) lttng_directory_handle_init_from_dirfd(&handle,
 403                         data->u.open.dirfd);
 404         /* Ownership of dirfd is transferred to the handle. */
 405         data->u.open.dirfd = -1;
 406
 407         fd = lttng_directory_handle_open_file(&handle,
 408                         data->u.open.path, data->u.open.flags,
 409                         data->u.open.mode);
 410         if (fd < 0) {
 411                 ret_value->u.ret = -1;
 412                 ret_value->u.open.fd = -1;
 413         } else {
 414                 ret_value->u.ret = 0;
 415                 ret_value->u.open.fd = fd;
 416         }
 417
 418         ret_value->_errno = errno;
 419         ret_value->_error = fd < 0;
 420         lttng_directory_handle_fini(&handle);
 421         return ret_value->u.ret;
 422 }
 423
 424 static
 425 int _unlink(struct run_as_data *data, struct run_as_ret *ret_value)
 426 {
 427         struct lttng_directory_handle handle;
 428
 429         (void) lttng_directory_handle_init_from_dirfd(&handle,
 430                         data->u.unlink.dirfd);
 431
 432         /* Ownership of dirfd is transferred to the handle. */
 433         data->u.unlink.dirfd = -1;
 434
 435         ret_value->u.ret = lttng_directory_handle_unlink_file(&handle,
 436                         data->u.unlink.path);
 437         ret_value->_errno = errno;
 438         ret_value->_error = (ret_value->u.ret) ? true : false;
 439         lttng_directory_handle_fini(&handle);
 440         return ret_value->u.ret;
 441 }
 442
 443 static
 444 int _rmdir(struct run_as_data *data, struct run_as_ret *ret_value)
 445 {
 446         struct lttng_directory_handle handle;
 447
 448         (void) lttng_directory_handle_init_from_dirfd(&handle,
 449                         data->u.rmdir.dirfd);
 450
 451         /* Ownership of dirfd is transferred to the handle. */
 452         data->u.rmdir.dirfd = -1;
 453
 454         ret_value->u.ret = lttng_directory_handle_remove_subdirectory(
 455                         &handle, data->u.rmdir.path);
 456         ret_value->_errno = errno;
 457         ret_value->_error = (ret_value->u.ret) ? true : false;
 458         lttng_directory_handle_fini(&handle);
 459         return ret_value->u.ret;
 460 }
 461
 462 static
 463 int _rmdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value)
 464 {
 465         struct lttng_directory_handle handle;
 466
 467         (void) lttng_directory_handle_init_from_dirfd(&handle,
 468                         data->u.rmdir.dirfd);
 469
 470         /* Ownership of dirfd is transferred to the handle. */
 471         data->u.rmdir.dirfd = -1;
 472
 473         ret_value->u.ret = lttng_directory_handle_remove_subdirectory_recursive(
 474                         &handle, data->u.rmdir.path);
 475         ret_value->_errno = errno;
 476         ret_value->_error = (ret_value->u.ret) ? true : false;
 477         lttng_directory_handle_fini(&handle);
 478         return ret_value->u.ret;
 479 }
 480
 481 static
 482 int _rename(struct run_as_data *data, struct run_as_ret *ret_value)
 483 {
 484         const char *old_path, *new_path;
 485         struct lttng_directory_handle old_handle, new_handle;
 486
 487         old_path = data->u.rename.old_path;
 488         new_path = data->u.rename.new_path;
 489
 490         (void) lttng_directory_handle_init_from_dirfd(&old_handle,
 491                         data->u.rename.dirfds[0]);
 492         (void) lttng_directory_handle_init_from_dirfd(&new_handle,
 493                         data->u.rename.dirfds[1]);
 494
 495         /* Ownership of dirfds are transferred to the handles. */
 496         data->u.rename.dirfds[0] = data->u.rename.dirfds[1] = -1;
 497
 498         /* Safe to call as we have transitioned to the requested uid/gid. */
 499         ret_value->u.ret = lttng_directory_handle_rename(
 500                         &old_handle, old_path, &new_handle, new_path);
 501         ret_value->_errno = errno;
 502         ret_value->_error = (ret_value->u.ret) ? true : false;
 503         lttng_directory_handle_fini(&old_handle);
 504         lttng_directory_handle_fini(&new_handle);
 505         return ret_value->u.ret;
 506 }
 507
 508 #ifdef HAVE_ELF_H
 509 static
 510 int _extract_elf_symbol_offset(struct run_as_data *data,
 511                 struct run_as_ret *ret_value)
 512 {
 513         int ret = 0;
 514
 515         ret_value->_error = false;
 516         ret = lttng_elf_get_symbol_offset(data->u.extract_elf_symbol_offset.fd,
 517                          data->u.extract_elf_symbol_offset.function,
 518                          &ret_value->u.extract_elf_symbol_offset.offset);
 519         if (ret) {
 520                 DBG("Failed to extract ELF function offset");
 521                 ret_value->_error = true;
 522         }
 523
 524         return ret;
 525 }
 526
 527 static
 528 int _extract_sdt_probe_offsets(struct run_as_data *data,
 529                 struct run_as_ret *ret_value)
 530 {
 531         int ret = 0;
 532         uint64_t *offsets = NULL;
 533         uint32_t num_offset;
 534
 535         ret_value->_error = false;
 536
 537         /* On success, this call allocates the offsets paramater. */
 538         ret = lttng_elf_get_sdt_probe_offsets(
 539                         data->u.extract_sdt_probe_offsets.fd,
 540                         data->u.extract_sdt_probe_offsets.provider_name,
 541                         data->u.extract_sdt_probe_offsets.probe_name,
 542                         &offsets, &num_offset);
 543
 544         if (ret) {
 545                 DBG("Failed to extract SDT probe offsets");
 546                 ret_value->_error = true;
 547                 goto end;
 548         }
 549
 550         if (num_offset <= 0 || num_offset > LTTNG_KERNEL_MAX_UPROBE_NUM) {
 551                 DBG("Wrong number of probes.");
 552                 ret = -1;
 553                 ret_value->_error = true;
 554                 goto free_offset;
 555         }
 556
 557         /* Copy the content of the offsets array to the ret struct. */
 558         memcpy(ret_value->u.extract_sdt_probe_offsets.offsets,
 559                         offsets, num_offset * sizeof(uint64_t));
 560
 561         ret_value->u.extract_sdt_probe_offsets.num_offset = num_offset;
 562
 563 free_offset:
 564         free(offsets);
 565 end:
 566         return ret;
 567 }
 568 #else
 569 static
 570 int _extract_elf_symbol_offset(struct run_as_data *data,
 571                 struct run_as_ret *ret_value)
 572 {
 573         ERR("Unimplemented runas command RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET");
 574         return -1;
 575 }
 576
 577 static
 578 int _extract_sdt_probe_offsets(struct run_as_data *data,
 579                 struct run_as_ret *ret_value)
 580 {
 581         ERR("Unimplemented runas command RUN_AS_EXTRACT_SDT_PROBE_OFFSETS");
 582         return -1;
 583 }
 584 #endif
 585
 586 static
 587 run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd)
 588 {
 589         switch (cmd) {
 590         case RUN_AS_MKDIR:
 591         case RUN_AS_MKDIRAT:
 592                 return _mkdirat;
 593         case RUN_AS_MKDIR_RECURSIVE:
 594         case RUN_AS_MKDIRAT_RECURSIVE:
 595                 return _mkdirat_recursive;
 596         case RUN_AS_OPEN:
 597         case RUN_AS_OPENAT:
 598                 return _open;
 599         case RUN_AS_UNLINK:
 600         case RUN_AS_UNLINKAT:
 601                 return _unlink;
 602         case RUN_AS_RMDIR:
 603         case RUN_AS_RMDIRAT:
 604                 return _rmdir;
 605         case RUN_AS_RMDIR_RECURSIVE:
 606         case RUN_AS_RMDIRAT_RECURSIVE:
 607                 return _rmdir_recursive;
 608         case RUN_AS_RENAME:
 609         case RUN_AS_RENAMEAT:
 610                 return _rename;
 611         case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
 612                 return _extract_elf_symbol_offset;
 613         case RUN_AS_EXTRACT_SDT_PROBE_OFFSETS:
 614                 return _extract_sdt_probe_offsets;
 615         default:
 616                 ERR("Unknown command %d", (int) cmd);
 617                 return NULL;
 618         }
 619 }
 620
 621 static
 622 int do_send_fds(int sock, const int *fds, unsigned int fd_count)
 623 {
 624         ssize_t len;
 625         unsigned int i;
 626
 627         for (i = 0; i < fd_count; i++) {
 628                 if (fds[i] < 0) {
 629                         ERR("Attempt to send invalid file descriptor to master (fd = %i)",
 630                                         fds[i]);
 631                         /* Return 0 as this is not a fatal error. */
 632                         return 0;
 633                 }
 634         }
 635
 636         len = lttcomm_send_fds_unix_sock(sock, fds, fd_count);
 637         return len < 0 ? -1 : 0;
 638 }
 639
 640 static
 641 int do_recv_fds(int sock, int *fds, unsigned int fd_count)
 642 {
 643         int ret = 0;
 644         unsigned int i;
 645         ssize_t len;
 646
 647         len = lttcomm_recv_fds_unix_sock(sock, fds, fd_count);
 648         if (len == 0) {
 649                 ret = -1;
 650                 goto end;
 651         } else if (len < 0) {
 652                 PERROR("Failed to receive file descriptors from socket");
 653                 ret = -1;
 654                 goto end;
 655         }
 656
 657         for (i = 0; i < fd_count; i++) {
 658                 if (fds[i] < 0) {
 659                         ERR("Invalid file descriptor received from worker (fd = %i)", fds[i]);
 660                         /* Return 0 as this is not a fatal error. */
 661                 }
 662         }
 663 end:
 664         return ret;
 665 }
 666
 667 static
 668 int send_fds_to_worker(const struct run_as_worker *worker,
 669                 const struct run_as_data *data)
 670 {
 671         int ret = 0;
 672         unsigned int i;
 673
 674         if (COMMAND_USE_CWD_FD(data) || COMMAND_IN_FD_COUNT(data) == 0) {
 675                 goto end;
 676         }
 677
 678         for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 679                 if (COMMAND_IN_FDS(data)[i] < 0) {
 680                         ERR("Refusing to send invalid fd to worker (fd = %i)",
 681                                         COMMAND_IN_FDS(data)[i]);
 682                         ret = -1;
 683                         goto end;
 684                 }
 685         }
 686
 687         ret = do_send_fds(worker->sockpair[0], COMMAND_IN_FDS(data),
 688                         COMMAND_IN_FD_COUNT(data));
 689         if (ret < 0) {
 690                 PERROR("Failed to send file descriptor to run-as worker");
 691                 ret = -1;
 692                 goto end;
 693         }
 694 end:
 695         return ret;
 696 }
 697
 698 static
 699 int send_fds_to_master(struct run_as_worker *worker, enum run_as_cmd cmd,
 700                 struct run_as_ret *run_as_ret)
 701 {
 702         int ret = 0;
 703         unsigned int i;
 704
 705         if (COMMAND_OUT_FD_COUNT(cmd) == 0) {
 706                 goto end;
 707         }
 708
 709         ret = do_send_fds(worker->sockpair[1], COMMAND_OUT_FDS(cmd, run_as_ret),
 710                         COMMAND_OUT_FD_COUNT(cmd));
 711         if (ret < 0) {
 712                 PERROR("Failed to send file descriptor to master process");
 713                 goto end;
 714         }
 715
 716         for (i = 0; i < COMMAND_OUT_FD_COUNT(cmd); i++) {
 717                 int ret_close = close(COMMAND_OUT_FDS(cmd, run_as_ret)[i]);
 718
 719                 if (ret_close < 0) {
 720                         PERROR("Failed to close result file descriptor");
 721                 }
 722         }
 723 end:
 724         return ret;
 725 }
 726
 727 static
 728 int recv_fds_from_worker(const struct run_as_worker *worker, enum run_as_cmd cmd,
 729                 struct run_as_ret *run_as_ret)
 730 {
 731         int ret = 0;
 732
 733         if (COMMAND_OUT_FD_COUNT(cmd) == 0) {
 734                 goto end;
 735         }
 736
 737         ret = do_recv_fds(worker->sockpair[0], COMMAND_OUT_FDS(cmd, run_as_ret),
 738                         COMMAND_OUT_FD_COUNT(cmd));
 739         if (ret < 0) {
 740                 PERROR("Failed to receive file descriptor from run-as worker");
 741                 ret = -1;
 742         }
 743 end:
 744         return ret;
 745 }
 746
 747 static
 748 int recv_fds_from_master(struct run_as_worker *worker, struct run_as_data *data)
 749 {
 750         int ret = 0;
 751
 752         if (COMMAND_USE_CWD_FD(data)) {
 753                 unsigned int i;
 754
 755                 for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 756                         COMMAND_IN_FDS(data)[i] = AT_FDCWD;
 757                 }
 758                 goto end;
 759         }
 760
 761         ret = do_recv_fds(worker->sockpair[1], COMMAND_IN_FDS(data),
 762                         COMMAND_IN_FD_COUNT(data));
 763         if (ret < 0) {
 764                 PERROR("Failed to receive file descriptors from master process");
 765                 ret = -1;
 766         }
 767 end:
 768         return ret;
 769 }
 770
 771 static
 772 int cleanup_received_fds(struct run_as_data *data)
 773 {
 774         int ret = 0, i;
 775
 776         for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) {
 777                 if (COMMAND_IN_FDS(data)[i] == -1) {
 778                         continue;
 779                 }
 780                 ret = close(COMMAND_IN_FDS(data)[i]);
 781                 if (ret) {
 782                         PERROR("Failed to close file descriptor received fd in run-as worker");
 783                         goto end;
 784                 }
 785         }
 786 end:
 787         return ret;
 788 }
 789
 790 /*
 791  * Return < 0 on error, 0 if OK, 1 on hangup.
 792  */
 793 static
 794 int handle_one_cmd(struct run_as_worker *worker)
 795 {
 796         int ret = 0;
 797         struct run_as_data data = {};
 798         ssize_t readlen, writelen;
 799         struct run_as_ret sendret = {};
 800         run_as_fct cmd;
 801         uid_t prev_euid;
 802
 803         /*
 804          * Stage 1: Receive run_as_data struct from the master.
 805          * The structure contains the command type and all the parameters needed for
 806          * its execution
 807          */
 808         readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data,
 809                         sizeof(data));
 810         if (readlen == 0) {
 811                 /* hang up */
 812                 ret = 1;
 813                 goto end;
 814         }
 815         if (readlen < sizeof(data)) {
 816                 PERROR("lttcomm_recv_unix_sock error");
 817                 ret = -1;
 818                 goto end;
 819         }
 820
 821         cmd = run_as_enum_to_fct(data.cmd);
 822         if (!cmd) {
 823                 ret = -1;
 824                 goto end;
 825         }
 826
 827         /*
 828          * Stage 2: Receive file descriptor from master.
 829          * Some commands need a file descriptor as input so if it's needed we
 830          * receive the fd using the Unix socket.
 831          */
 832         ret = recv_fds_from_master(worker, &data);
 833         if (ret < 0) {
 834                 PERROR("recv_fd_from_master error");
 835                 ret = -1;
 836                 goto end;
 837         }
 838
 839         prev_euid = getuid();
 840         if (data.gid != getegid()) {
 841                 ret = setegid(data.gid);
 842                 if (ret < 0) {
 843                         sendret._error = true;
 844                         sendret._errno = errno;
 845                         PERROR("setegid");
 846                         goto write_return;
 847                 }
 848         }
 849         if (data.uid != prev_euid) {
 850                 ret = seteuid(data.uid);
 851                 if (ret < 0) {
 852                         sendret._error = true;
 853                         sendret._errno = errno;
 854                         PERROR("seteuid");
 855                         goto write_return;
 856                 }
 857         }
 858
 859         /*
 860          * Also set umask to 0 for mkdir executable bit.
 861          */
 862         umask(0);
 863
 864         /*
 865          * Stage 3: Execute the command
 866          */
 867         ret = (*cmd)(&data, &sendret);
 868         if (ret < 0) {
 869                 DBG("Execution of command returned an error");
 870         }
 871
 872 write_return:
 873         ret = cleanup_received_fds(&data);
 874         if (ret < 0) {
 875                 ERR("Error cleaning up FD");
 876                 goto end;
 877         }
 878
 879         /*
 880          * Stage 4: Send run_as_ret structure to the master.
 881          * This structure contain the return value of the command and the errno.
 882          */
 883         writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
 884                         sizeof(sendret));
 885         if (writelen < sizeof(sendret)) {
 886                 PERROR("lttcomm_send_unix_sock error");
 887                 ret = -1;
 888                 goto end;
 889         }
 890
 891         /*
 892          * Stage 5: Send resulting file descriptors to the master.
 893          */
 894         ret = send_fds_to_master(worker, data.cmd, &sendret);
 895         if (ret < 0) {
 896                 DBG("Sending FD to master returned an error");
 897                 goto end;
 898         }
 899
 900         if (seteuid(prev_euid) < 0) {
 901                 PERROR("seteuid");
 902                 ret = -1;
 903                 goto end;
 904         }
 905         ret = 0;
 906 end:
 907         return ret;
 908 }
 909
 910 static
 911 int run_as_worker(struct run_as_worker *worker)
 912 {
 913         int ret;
 914         ssize_t writelen;
 915         struct run_as_ret sendret;
 916         size_t proc_orig_len;
 917
 918         /*
 919          * Initialize worker. Set a different process cmdline.
 920          */
 921         proc_orig_len = strlen(worker->procname);
 922         memset(worker->procname, 0, proc_orig_len);
 923         strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len);
 924
 925         ret = lttng_prctl(PR_SET_NAME,
 926                         (unsigned long) DEFAULT_RUN_AS_WORKER_NAME, 0, 0, 0);
 927         if (ret && ret != -ENOSYS) {
 928                 /* Don't fail as this is not essential. */
 929                 PERROR("prctl PR_SET_NAME");
 930         }
 931
 932         memset(&sendret, 0, sizeof(sendret));
 933
 934         writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
 935                         sizeof(sendret));
 936         if (writelen < sizeof(sendret)) {
 937                 PERROR("lttcomm_send_unix_sock error");
 938                 ret = EXIT_FAILURE;
 939                 goto end;
 940         }
 941
 942         for (;;) {
 943                 ret = handle_one_cmd(worker);
 944                 if (ret < 0) {
 945                         ret = EXIT_FAILURE;
 946                         goto end;
 947                 } else if (ret > 0) {
 948                         break;
 949                 } else {
 950                         continue;       /* Next command. */
 951                 }
 952         }
 953         ret = EXIT_SUCCESS;
 954 end:
 955         return ret;
 956 }
 957
 958 static
 959 int run_as_cmd(struct run_as_worker *worker,
 960                 enum run_as_cmd cmd,
 961                 struct run_as_data *data,
 962                 struct run_as_ret *ret_value,
 963                 uid_t uid, gid_t gid)
 964 {
 965         int ret = 0;
 966         ssize_t readlen, writelen;
 967
 968         /*
 969          * If we are non-root, we can only deal with our own uid.
 970          */
 971         if (geteuid() != 0) {
 972                 if (uid != geteuid()) {
 973                         ret = -1;
 974                         ret_value->_errno = EPERM;
 975                         ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
 976                                 (int) uid, (int) geteuid());
 977                         goto end;
 978                 }
 979         }
 980
 981         data->cmd = cmd;
 982         data->uid = uid;
 983         data->gid = gid;
 984
 985         /*
 986          * Stage 1: Send the run_as_data struct to the worker process
 987          */
 988         writelen = lttcomm_send_unix_sock(worker->sockpair[0], data,
 989                         sizeof(*data));
 990         if (writelen < sizeof(*data)) {
 991                 PERROR("Error writing message to run_as");
 992                 ret = -1;
 993                 ret_value->_errno = EIO;
 994                 goto end;
 995         }
 996
 997         /*
 998          * Stage 2: Send file descriptor to the worker process if needed
 999          */
1000         ret = send_fds_to_worker(worker, data);
1001         if (ret) {
1002                 PERROR("do_send_fd error");
1003                 ret = -1;
1004                 ret_value->_errno = EIO;
1005                 goto end;
1006         }
1007
1008         /*
1009          * Stage 3: Wait for the execution of the command
1010          */
1011
1012         /*
1013          * Stage 4: Receive the run_as_ret struct containing the return value and
1014          * errno
1015          */
1016         readlen = lttcomm_recv_unix_sock(worker->sockpair[0], ret_value,
1017                         sizeof(*ret_value));
1018         if (!readlen) {
1019                 ERR("Run-as worker has hung-up during run_as_cmd");
1020                 ret = -1;
1021                 ret_value->_errno = EIO;
1022                 goto end;
1023         } else if (readlen < sizeof(*ret_value)) {
1024                 PERROR("Error reading response from run_as");
1025                 ret = -1;
1026                 ret_value->_errno = errno;
1027                 goto end;
1028         }
1029
1030         if (ret_value->_error) {
1031                 /* Skip stage 5 on error as there will be no fd to receive. */
1032                 goto end;
1033         }
1034
1035         /*
1036          * Stage 5: Receive file descriptor if needed
1037          */
1038         ret = recv_fds_from_worker(worker, cmd, ret_value);
1039         if (ret < 0) {
1040                 ERR("Error receiving fd");
1041                 ret = -1;
1042                 ret_value->_errno = EIO;
1043         }
1044
1045 end:
1046         return ret;
1047 }
1048
1049 /*
1050  * This is for debugging ONLY and should not be considered secure.
1051  */
1052 static
1053 int run_as_noworker(enum run_as_cmd cmd,
1054                 struct run_as_data *data, struct run_as_ret *ret_value,
1055                 uid_t uid, gid_t gid)
1056 {
1057         int ret, saved_errno;
1058         mode_t old_mask;
1059         run_as_fct fct;
1060
1061         fct = run_as_enum_to_fct(cmd);
1062         if (!fct) {
1063                 errno = -ENOSYS;
1064                 ret = -1;
1065                 goto end;
1066         }
1067         old_mask = umask(0);
1068         ret = fct(data, ret_value);
1069         saved_errno = ret_value->_errno;
1070         umask(old_mask);
1071         errno = saved_errno;
1072 end:
1073         return ret;
1074 }
1075
1076 static
1077 int reset_sighandler(void)
1078 {
1079         int sig;
1080
1081         DBG("Resetting run_as worker signal handlers to default");
1082         for (sig = 1; sig <= 31; sig++) {
1083                 (void) signal(sig, SIG_DFL);
1084         }
1085         return 0;
1086 }
1087
1088 static
1089 void worker_sighandler(int sig)
1090 {
1091         const char *signame;
1092
1093         /*
1094          * The worker will inherit its parent's signals since they are part of
1095          * the same process group. However, in the case of SIGINT and SIGTERM,
1096          * we want to give the worker a chance to teardown gracefully when its
1097          * parent closes the command socket.
1098          */
1099         switch (sig) {
1100         case SIGINT:
1101                 signame = "SIGINT";
1102                 break;
1103         case SIGTERM:
1104                 signame = "SIGTERM";
1105                 break;
1106         default:
1107                 signame = NULL;
1108         }
1109
1110         if (signame) {
1111                 DBG("run_as worker received signal %s", signame);
1112         } else {
1113                 DBG("run_as_worker received signal %d", sig);
1114         }
1115 }
1116
1117 static
1118 int set_worker_sighandlers(void)
1119 {
1120         int ret = 0;
1121         sigset_t sigset;
1122         struct sigaction sa;
1123
1124         if ((ret = sigemptyset(&sigset)) < 0) {
1125                 PERROR("sigemptyset");
1126                 goto end;
1127         }
1128
1129         sa.sa_handler = worker_sighandler;
1130         sa.sa_mask = sigset;
1131         sa.sa_flags = 0;
1132         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
1133                 PERROR("sigaction SIGINT");
1134                 goto end;
1135         }
1136
1137         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
1138                 PERROR("sigaction SIGTERM");
1139                 goto end;
1140         }
1141
1142         DBG("run_as signal handler set for SIGTERM and SIGINT");
1143 end:
1144         return ret;
1145 }
1146
1147 static
1148 int run_as_create_worker_no_lock(const char *procname,
1149                 post_fork_cleanup_cb clean_up_func,
1150                 void *clean_up_user_data)
1151 {
1152         pid_t pid;
1153         int i, ret = 0;
1154         ssize_t readlen;
1155         struct run_as_ret recvret;
1156         struct run_as_worker *worker;
1157
1158         assert(!global_worker);
1159         if (!use_clone()) {
1160                 /*
1161                  * Don't initialize a worker, all run_as tasks will be performed
1162                  * in the current process.
1163                  */
1164                 ret = 0;
1165                 goto end;
1166         }
1167         worker = zmalloc(sizeof(*worker));
1168         if (!worker) {
1169                 ret = -ENOMEM;
1170                 goto end;
1171         }
1172         worker->procname = strdup(procname);
1173         if (!worker->procname) {
1174                 ret = -ENOMEM;
1175                 goto error_procname_alloc;
1176         }
1177         /* Create unix socket. */
1178         if (lttcomm_create_anon_unix_socketpair(worker->sockpair) < 0) {
1179                 ret = -1;
1180                 goto error_sock;
1181         }
1182
1183         /* Fork worker. */
1184         pid = fork();
1185         if (pid < 0) {
1186                 PERROR("fork");
1187                 ret = -1;
1188                 goto error_fork;
1189         } else if (pid == 0) {
1190                 /* Child */
1191
1192                 reset_sighandler();
1193
1194                 set_worker_sighandlers();
1195                 if (clean_up_func) {
1196                         if (clean_up_func(clean_up_user_data) < 0) {
1197                                 ERR("Run-as post-fork clean-up failed, exiting.");
1198                                 exit(EXIT_FAILURE);
1199                         }
1200                 }
1201
1202                 /* Just close, no shutdown. */
1203                 if (close(worker->sockpair[0])) {
1204                         PERROR("close");
1205                         exit(EXIT_FAILURE);
1206                 }
1207
1208                 /*
1209                  * Close all FDs aside from STDIN, STDOUT, STDERR and sockpair[1]
1210                  * Sockpair[1] is used as a control channel with the master
1211                  */
1212                 for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
1213                         if (i != worker->sockpair[1]) {
1214                                 (void) close(i);
1215                         }
1216                 }
1217
1218                 worker->sockpair[0] = -1;
1219                 ret = run_as_worker(worker);
1220                 if (lttcomm_close_unix_sock(worker->sockpair[1])) {
1221                         PERROR("close");
1222                         ret = -1;
1223                 }
1224                 worker->sockpair[1] = -1;
1225                 free(worker->procname);
1226                 free(worker);
1227                 LOG(ret ? PRINT_ERR : PRINT_DBG, "run_as worker exiting (ret = %d)", ret);
1228                 exit(ret ? EXIT_FAILURE : EXIT_SUCCESS);
1229         } else {
1230                 /* Parent */
1231
1232                 /* Just close, no shutdown. */
1233                 if (close(worker->sockpair[1])) {
1234                         PERROR("close");
1235                         ret = -1;
1236                         goto error_fork;
1237                 }
1238                 worker->sockpair[1] = -1;
1239                 worker->pid = pid;
1240                 /* Wait for worker to become ready. */
1241                 readlen = lttcomm_recv_unix_sock(worker->sockpair[0],
1242                                 &recvret, sizeof(recvret));
1243                 if (readlen < sizeof(recvret)) {
1244                         ERR("readlen: %zd", readlen);
1245                         PERROR("Error reading response from run_as at creation");
1246                         ret = -1;
1247                         goto error_fork;
1248                 }
1249                 global_worker = worker;
1250         }
1251 end:
1252         return ret;
1253
1254         /* Error handling. */
1255 error_fork:
1256         for (i = 0; i < 2; i++) {
1257                 if (worker->sockpair[i] < 0) {
1258                         continue;
1259                 }
1260                 if (lttcomm_close_unix_sock(worker->sockpair[i])) {
1261                         PERROR("close");
1262                 }
1263                 worker->sockpair[i] = -1;
1264         }
1265 error_sock:
1266         free(worker->procname);
1267 error_procname_alloc:
1268         free(worker);
1269         return ret;
1270 }
1271
1272 static
1273 void run_as_destroy_worker_no_lock(void)
1274 {
1275         struct run_as_worker *worker = global_worker;
1276
1277         DBG("Destroying run_as worker");
1278         if (!worker) {
1279                 return;
1280         }
1281         /* Close unix socket */
1282         DBG("Closing run_as worker socket");
1283         if (lttcomm_close_unix_sock(worker->sockpair[0])) {
1284                 PERROR("close");
1285         }
1286         worker->sockpair[0] = -1;
1287         /* Wait for worker. */
1288         for (;;) {
1289                 int status;
1290                 pid_t wait_ret;
1291
1292                 wait_ret = waitpid(worker->pid, &status, 0);
1293                 if (wait_ret < 0) {
1294                         if (errno == EINTR) {
1295                                 continue;
1296                         }
1297                         PERROR("waitpid");
1298                         break;
1299                 }
1300
1301                 if (WIFEXITED(status)) {
1302                         LOG(WEXITSTATUS(status) == 0 ? PRINT_DBG : PRINT_ERR,
1303                                         DEFAULT_RUN_AS_WORKER_NAME " terminated with status code %d",
1304                                         WEXITSTATUS(status));
1305                         break;
1306                 } else if (WIFSIGNALED(status)) {
1307                         ERR(DEFAULT_RUN_AS_WORKER_NAME " was killed by signal %d",
1308                                         WTERMSIG(status));
1309                         break;
1310                 }
1311         }
1312         free(worker->procname);
1313         free(worker);
1314         global_worker = NULL;
1315 }
1316
1317 static
1318 int run_as_restart_worker(struct run_as_worker *worker)
1319 {
1320         int ret = 0;
1321         char *procname = NULL;
1322
1323         procname = worker->procname;
1324
1325         /* Close socket to run_as worker process and clean up the zombie process */
1326         run_as_destroy_worker_no_lock();
1327
1328         /* Create a new run_as worker process*/
1329         ret = run_as_create_worker_no_lock(procname, NULL, NULL);
1330         if (ret < 0 ) {
1331                 ERR("Restarting the worker process failed");
1332                 ret = -1;
1333                 goto err;
1334         }
1335 err:
1336         return ret;
1337 }
1338
1339 static
1340 int run_as(enum run_as_cmd cmd, struct run_as_data *data,
1341                    struct run_as_ret *ret_value, uid_t uid, gid_t gid)
1342 {
1343         int ret, saved_errno;
1344
1345         pthread_mutex_lock(&worker_lock);
1346         if (use_clone()) {
1347                 DBG("Using run_as worker");
1348
1349                 assert(global_worker);
1350
1351                 ret = run_as_cmd(global_worker, cmd, data, ret_value, uid, gid);
1352                 saved_errno = ret_value->_errno;
1353
1354                 /*
1355                  * If the worker thread crashed the errno is set to EIO. we log
1356                  * the error and  start a new worker process.
1357                  */
1358                 if (ret == -1 && saved_errno == EIO) {
1359                         DBG("Socket closed unexpectedly... "
1360                                         "Restarting the worker process");
1361                         ret = run_as_restart_worker(global_worker);
1362                         if (ret == -1) {
1363                                 ERR("Failed to restart worker process.");
1364                                 goto err;
1365                         }
1366                 }
1367         } else {
1368                 DBG("Using run_as without worker");
1369                 ret = run_as_noworker(cmd, data, ret_value, uid, gid);
1370         }
1371 err:
1372         pthread_mutex_unlock(&worker_lock);
1373         return ret;
1374 }
1375
1376 LTTNG_HIDDEN
1377 int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid)
1378 {
1379         return run_as_mkdirat_recursive(AT_FDCWD, path, mode, uid, gid);
1380 }
1381
1382 LTTNG_HIDDEN
1383 int run_as_mkdirat_recursive(int dirfd, const char *path, mode_t mode,
1384                 uid_t uid, gid_t gid)
1385 {
1386         int ret;
1387         struct run_as_data data = {};
1388         struct run_as_ret run_as_ret = {};
1389
1390         DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d",
1391                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1392                         path, (int) mode, (int) uid, (int) gid);
1393         ret = lttng_strncpy(data.u.mkdir.path, path,
1394                         sizeof(data.u.mkdir.path));
1395         if (ret) {
1396                 ERR("Failed to copy path argument of mkdirat recursive command");
1397                 goto error;
1398         }
1399         data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0';
1400         data.u.mkdir.mode = mode;
1401         data.u.mkdir.dirfd = dirfd;
1402         run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR_RECURSIVE : RUN_AS_MKDIRAT_RECURSIVE,
1403                         &data, &run_as_ret, uid, gid);
1404         errno = run_as_ret._errno;
1405         ret = run_as_ret.u.ret;
1406 error:
1407         return ret;
1408 }
1409
1410 LTTNG_HIDDEN
1411 int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid)
1412 {
1413         return run_as_mkdirat(AT_FDCWD, path, mode, uid, gid);
1414 }
1415
1416 LTTNG_HIDDEN
1417 int run_as_mkdirat(int dirfd, const char *path, mode_t mode,
1418                 uid_t uid, gid_t gid)
1419 {
1420         int ret;
1421         struct run_as_data data = {};
1422         struct run_as_ret run_as_ret = {};
1423
1424         DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d",
1425                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1426                         path, (int) mode, (int) uid, (int) gid);
1427         ret = lttng_strncpy(data.u.mkdir.path, path,
1428                         sizeof(data.u.mkdir.path));
1429         if (ret) {
1430                 ERR("Failed to copy path argument of mkdirat command");
1431                 goto error;
1432         }
1433         data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0';
1434         data.u.mkdir.mode = mode;
1435         data.u.mkdir.dirfd = dirfd;
1436         run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR : RUN_AS_MKDIRAT,
1437                         &data, &run_as_ret, uid, gid);
1438         errno = run_as_ret._errno;
1439         ret = run_as_ret.u.ret;
1440 error:
1441         return ret;
1442 }
1443
1444 LTTNG_HIDDEN
1445 int run_as_open(const char *path, int flags, mode_t mode, uid_t uid,
1446                 gid_t gid)
1447 {
1448         return run_as_openat(AT_FDCWD, path, flags, mode, uid, gid);
1449 }
1450
1451 LTTNG_HIDDEN
1452 int run_as_openat(int dirfd, const char *path, int flags, mode_t mode,
1453                 uid_t uid, gid_t gid)
1454 {
1455         int ret;
1456         struct run_as_data data = {};
1457         struct run_as_ret run_as_ret = {};
1458
1459         DBG3("openat() fd = %d%s, path = %s, flags = %X, mode = %d, uid %d, gid %d",
1460                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1461                         path, flags, (int) mode, (int) uid, (int) gid);
1462         ret = lttng_strncpy(data.u.open.path, path, sizeof(data.u.open.path));
1463         if (ret) {
1464                 ERR("Failed to copy path argument of open command");
1465                 goto error;
1466         }
1467         data.u.open.flags = flags;
1468         data.u.open.mode = mode;
1469         data.u.open.dirfd = dirfd;
1470         run_as(dirfd == AT_FDCWD ? RUN_AS_OPEN : RUN_AS_OPENAT,
1471                         &data, &run_as_ret, uid, gid);
1472         errno = run_as_ret._errno;
1473         ret = run_as_ret.u.ret < 0 ? run_as_ret.u.ret :
1474                         run_as_ret.u.open.fd;
1475 error:
1476         return ret;
1477 }
1478
1479 LTTNG_HIDDEN
1480 int run_as_unlink(const char *path, uid_t uid, gid_t gid)
1481 {
1482         return run_as_unlinkat(AT_FDCWD, path, uid, gid);
1483 }
1484
1485 LTTNG_HIDDEN
1486 int run_as_unlinkat(int dirfd, const char *path, uid_t uid, gid_t gid)
1487 {
1488         int ret;
1489         struct run_as_data data = {};
1490         struct run_as_ret run_as_ret = {};
1491
1492         DBG3("unlinkat() fd = %d%s, path = %s, uid = %d, gid = %d",
1493                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1494                         path, (int) uid, (int) gid);
1495         ret = lttng_strncpy(data.u.unlink.path, path,
1496                         sizeof(data.u.unlink.path));
1497         if (ret) {
1498                 goto error;
1499         }
1500         data.u.unlink.dirfd = dirfd;
1501         run_as(dirfd == AT_FDCWD ? RUN_AS_UNLINK : RUN_AS_UNLINKAT, &data,
1502                         &run_as_ret, uid, gid);
1503         errno = run_as_ret._errno;
1504         ret = run_as_ret.u.ret;
1505 error:
1506         return ret;
1507 }
1508
1509 LTTNG_HIDDEN
1510 int run_as_rmdir(const char *path, uid_t uid, gid_t gid)
1511 {
1512         return run_as_rmdirat(AT_FDCWD, path, uid, gid);
1513 }
1514
1515 LTTNG_HIDDEN
1516 int run_as_rmdirat(int dirfd, const char *path, uid_t uid, gid_t gid)
1517 {
1518         int ret;
1519         struct run_as_data data = {};
1520         struct run_as_ret run_as_ret = {};
1521
1522         DBG3("rmdirat() fd = %d%s, path = %s, uid = %d, gid = %d",
1523                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1524                         path, (int) uid, (int) gid);
1525         ret = lttng_strncpy(data.u.rmdir.path, path,
1526                         sizeof(data.u.rmdir.path));
1527         if (ret) {
1528                 goto error;
1529         }
1530         data.u.rmdir.dirfd = dirfd;
1531         run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR : RUN_AS_RMDIRAT, &data,
1532                         &run_as_ret, uid, gid);
1533         errno = run_as_ret._errno;
1534         ret = run_as_ret.u.ret;
1535 error:
1536         return ret;
1537 }
1538
1539 LTTNG_HIDDEN
1540 int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid)
1541 {
1542         return run_as_rmdirat_recursive(AT_FDCWD, path, uid, gid);
1543 }
1544
1545 LTTNG_HIDDEN
1546 int run_as_rmdirat_recursive(int dirfd, const char *path, uid_t uid, gid_t gid)
1547 {
1548         int ret;
1549         struct run_as_data data = {};
1550         struct run_as_ret run_as_ret = {};
1551
1552         DBG3("rmdirat() recursive fd = %d%s, path = %s, uid = %d, gid = %d",
1553                         dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1554                         path, (int) uid, (int) gid);
1555         ret = lttng_strncpy(data.u.rmdir.path, path,
1556                         sizeof(data.u.rmdir.path));
1557         if (ret) {
1558                 goto error;
1559         }
1560         data.u.rmdir.dirfd = dirfd;
1561         run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR_RECURSIVE : RUN_AS_RMDIRAT_RECURSIVE,
1562                         &data, &run_as_ret, uid, gid);
1563         errno = run_as_ret._errno;
1564         ret = run_as_ret.u.ret;
1565 error:
1566         return ret;
1567 }
1568
1569 LTTNG_HIDDEN
1570 int run_as_rename(const char *old, const char *new, uid_t uid, gid_t gid)
1571 {
1572         return run_as_renameat(AT_FDCWD, old, AT_FDCWD, new, uid, gid);
1573 }
1574
1575 LTTNG_HIDDEN
1576 int run_as_renameat(int old_dirfd, const char *old_name,
1577                 int new_dirfd, const char *new_name, uid_t uid, gid_t gid)
1578 {
1579         int ret;
1580         struct run_as_data data = {};
1581         struct run_as_ret run_as_ret = {};
1582
1583         DBG3("renameat() old_dirfd = %d%s, old_name = %s, new_dirfd = %d%s, new_name = %s, uid = %d, gid = %d",
1584                         old_dirfd, old_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1585                         old_name,
1586                         new_dirfd, new_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "",
1587                         new_name, (int) uid, (int) gid);
1588         ret = lttng_strncpy(data.u.rename.old_path, old_name,
1589                         sizeof(data.u.rename.old_path));
1590         if (ret) {
1591                 goto error;
1592         }
1593         ret = lttng_strncpy(data.u.rename.new_path, new_name,
1594                         sizeof(data.u.rename.new_path));
1595         if (ret) {
1596                 goto error;
1597         }
1598
1599         data.u.rename.dirfds[0] = old_dirfd;
1600         data.u.rename.dirfds[1] = new_dirfd;
1601         run_as(old_dirfd == AT_FDCWD && new_dirfd == AT_FDCWD ?
1602                         RUN_AS_RENAME : RUN_AS_RENAMEAT,
1603                         &data, &run_as_ret, uid, gid);
1604         errno = run_as_ret._errno;
1605         ret = run_as_ret.u.ret;
1606 error:
1607         return ret;
1608 }
1609
1610 LTTNG_HIDDEN
1611 int run_as_extract_elf_symbol_offset(int fd, const char* function,
1612                 uid_t uid, gid_t gid, uint64_t *offset)
1613 {
1614         int ret;
1615         struct run_as_data data = {};
1616         struct run_as_ret run_as_ret = {};
1617
1618         DBG3("extract_elf_symbol_offset() on fd=%d and function=%s "
1619                         "with for uid %d and gid %d", fd, function,
1620                         (int) uid, (int) gid);
1621
1622         data.u.extract_elf_symbol_offset.fd = fd;
1623
1624         strncpy(data.u.extract_elf_symbol_offset.function, function, LTTNG_SYMBOL_NAME_LEN - 1);
1625         data.u.extract_elf_symbol_offset.function[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
1626         ret = lttng_strncpy(data.u.extract_elf_symbol_offset.function,
1627                         function,
1628                         sizeof(data.u.extract_elf_symbol_offset.function));
1629         if (ret) {
1630                 goto error;
1631         }
1632
1633         run_as(RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, &data, &run_as_ret, uid, gid);
1634         errno = run_as_ret._errno;
1635         if (run_as_ret._error) {
1636                 ret = -1;
1637                 goto error;
1638         }
1639
1640         *offset = run_as_ret.u.extract_elf_symbol_offset.offset;
1641 error:
1642         return ret;
1643 }
1644
1645 LTTNG_HIDDEN
1646 int run_as_extract_sdt_probe_offsets(int fd, const char* provider_name,
1647                 const char* probe_name, uid_t uid, gid_t gid,
1648                 uint64_t **offsets, uint32_t *num_offset)
1649 {
1650         int ret;
1651         struct run_as_data data = {};
1652         struct run_as_ret run_as_ret = {};
1653
1654         DBG3("extract_sdt_probe_offsets() on fd=%d, probe_name=%s and "
1655                         "provider_name=%s with for uid %d and gid %d", fd,
1656                         probe_name, provider_name, (int) uid, (int) gid);
1657
1658         data.u.extract_sdt_probe_offsets.fd = fd;
1659
1660         ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.probe_name, probe_name,
1661                         sizeof(data.u.extract_sdt_probe_offsets.probe_name));
1662         if (ret) {
1663                 goto error;
1664         }
1665         ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.provider_name,
1666                         provider_name,
1667                         sizeof(data.u.extract_sdt_probe_offsets.provider_name));
1668         if (ret) {
1669                 goto error;
1670         }
1671
1672         run_as(RUN_AS_EXTRACT_SDT_PROBE_OFFSETS, &data, &run_as_ret, uid, gid);
1673         errno = run_as_ret._errno;
1674         if (run_as_ret._error) {
1675                 ret = -1;
1676                 goto error;
1677         }
1678
1679         *num_offset = run_as_ret.u.extract_sdt_probe_offsets.num_offset;
1680         *offsets = zmalloc(*num_offset * sizeof(uint64_t));
1681         if (!*offsets) {
1682                 ret = -ENOMEM;
1683                 goto error;
1684         }
1685
1686         memcpy(*offsets, run_as_ret.u.extract_sdt_probe_offsets.offsets,
1687                         *num_offset * sizeof(uint64_t));
1688 error:
1689         return ret;
1690 }
1691
1692 LTTNG_HIDDEN
1693 int run_as_create_worker(const char *procname,
1694                 post_fork_cleanup_cb clean_up_func,
1695                 void *clean_up_user_data)
1696 {
1697         int ret;
1698
1699         pthread_mutex_lock(&worker_lock);
1700         ret = run_as_create_worker_no_lock(procname, clean_up_func,
1701                         clean_up_user_data);
1702         pthread_mutex_unlock(&worker_lock);
1703         return ret;
1704 }
1705
1706 LTTNG_HIDDEN
1707 void run_as_destroy_worker(void)
1708 {
1709         pthread_mutex_lock(&worker_lock);
1710         run_as_destroy_worker_no_lock();
1711         pthread_mutex_unlock(&worker_lock);
1712 }