| 1 | /* |
| 2 | * lttng-syscalls.c |
| 3 | * |
| 4 | * LTTng syscall probes. |
| 5 | * |
| 6 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 7 | * |
| 8 | * This library is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; only |
| 11 | * version 2.1 of the License. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with this library; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include <linux/compat.h> |
| 26 | #include <linux/err.h> |
| 27 | #include <linux/bitmap.h> |
| 28 | #include <asm/ptrace.h> |
| 29 | #include <asm/syscall.h> |
| 30 | |
| 31 | #include "wrapper/tracepoint.h" |
| 32 | #include "lttng-events.h" |
| 33 | |
| 34 | #ifndef CONFIG_COMPAT |
| 35 | # ifndef is_compat_task |
| 36 | # define is_compat_task() (0) |
| 37 | # endif |
| 38 | #endif |
| 39 | |
| 40 | static |
| 41 | void syscall_entry_probe(void *__data, struct pt_regs *regs, long id); |
| 42 | |
| 43 | /* |
| 44 | * Forward declarations for old kernels. |
| 45 | */ |
| 46 | struct mmsghdr; |
| 47 | struct rlimit64; |
| 48 | struct oldold_utsname; |
| 49 | struct old_utsname; |
| 50 | struct sel_arg_struct; |
| 51 | struct mmap_arg_struct; |
| 52 | |
| 53 | #ifdef IA32_NR_syscalls |
| 54 | #define NR_compat_syscalls IA32_NR_syscalls |
| 55 | #else |
| 56 | #define NR_compat_syscalls NR_syscalls |
| 57 | #endif |
| 58 | |
| 59 | /* |
| 60 | * Take care of NOARGS not supported by mainline. |
| 61 | */ |
| 62 | #define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print) |
| 63 | #define DEFINE_EVENT_NOARGS(template, name) |
| 64 | #define TRACE_EVENT_NOARGS(name, struct, assign, print) |
| 65 | |
| 66 | /* |
| 67 | * Create LTTng tracepoint probes. |
| 68 | */ |
| 69 | #define LTTNG_PACKAGE_BUILD |
| 70 | #define CREATE_TRACE_POINTS |
| 71 | #define TP_MODULE_NOINIT |
| 72 | #define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers |
| 73 | |
| 74 | #define PARAMS(args...) args |
| 75 | |
| 76 | /* Hijack probe callback for system calls */ |
| 77 | #undef TP_PROBE_CB |
| 78 | #define TP_PROBE_CB(_template) &syscall_entry_probe |
| 79 | #define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \ |
| 80 | TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\ |
| 81 | PARAMS(_struct), PARAMS(_assign), PARAMS(_printk)) |
| 82 | #define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \ |
| 83 | DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\ |
| 84 | PARAMS(_printk)) |
| 85 | #define SC_DEFINE_EVENT_NOARGS(_template, _name) \ |
| 86 | DEFINE_EVENT_NOARGS(_template, _name) |
| 87 | #undef TRACE_SYSTEM |
| 88 | #define TRACE_SYSTEM syscalls_integers |
| 89 | #include "instrumentation/syscalls/headers/syscalls_integers.h" |
| 90 | #undef TRACE_SYSTEM |
| 91 | #define TRACE_SYSTEM syscalls_pointers |
| 92 | #include "instrumentation/syscalls/headers/syscalls_pointers.h" |
| 93 | #undef TRACE_SYSTEM |
| 94 | #undef SC_TRACE_EVENT |
| 95 | #undef SC_DECLARE_EVENT_CLASS_NOARGS |
| 96 | #undef SC_DEFINE_EVENT_NOARGS |
| 97 | |
| 98 | #define TRACE_SYSTEM syscalls_unknown |
| 99 | #include "instrumentation/syscalls/headers/syscalls_unknown.h" |
| 100 | #undef TRACE_SYSTEM |
| 101 | |
| 102 | /* For compat syscalls */ |
| 103 | #undef _TRACE_SYSCALLS_integers_H |
| 104 | #undef _TRACE_SYSCALLS_pointers_H |
| 105 | |
| 106 | /* Hijack probe callback for system calls */ |
| 107 | #undef TP_PROBE_CB |
| 108 | #define TP_PROBE_CB(_template) &syscall_entry_probe |
| 109 | #define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \ |
| 110 | TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args), \ |
| 111 | PARAMS(_struct), PARAMS(_assign), \ |
| 112 | PARAMS(_printk)) |
| 113 | #define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \ |
| 114 | DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct), \ |
| 115 | PARAMS(_assign), PARAMS(_printk)) |
| 116 | #define SC_DEFINE_EVENT_NOARGS(_template, _name) \ |
| 117 | DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name) |
| 118 | #define TRACE_SYSTEM compat_syscalls_integers |
| 119 | #include "instrumentation/syscalls/headers/compat_syscalls_integers.h" |
| 120 | #undef TRACE_SYSTEM |
| 121 | #define TRACE_SYSTEM compat_syscalls_pointers |
| 122 | #include "instrumentation/syscalls/headers/compat_syscalls_pointers.h" |
| 123 | #undef TRACE_SYSTEM |
| 124 | #undef SC_TRACE_EVENT |
| 125 | #undef SC_DECLARE_EVENT_CLASS_NOARGS |
| 126 | #undef SC_DEFINE_EVENT_NOARGS |
| 127 | #undef TP_PROBE_CB |
| 128 | |
| 129 | #undef TP_MODULE_NOINIT |
| 130 | #undef LTTNG_PACKAGE_BUILD |
| 131 | #undef CREATE_TRACE_POINTS |
| 132 | |
| 133 | struct trace_syscall_entry { |
| 134 | void *func; |
| 135 | const struct lttng_event_desc *desc; |
| 136 | const struct lttng_event_field *fields; |
| 137 | unsigned int nrargs; |
| 138 | }; |
| 139 | |
| 140 | #define CREATE_SYSCALL_TABLE |
| 141 | |
| 142 | #undef TRACE_SYSCALL_TABLE |
| 143 | #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \ |
| 144 | [ _nr ] = { \ |
| 145 | .func = __event_probe__##_template, \ |
| 146 | .nrargs = (_nrargs), \ |
| 147 | .fields = __event_fields___##_template, \ |
| 148 | .desc = &__event_desc___##_name, \ |
| 149 | }, |
| 150 | |
| 151 | static const struct trace_syscall_entry sc_table[] = { |
| 152 | #include "instrumentation/syscalls/headers/syscalls_integers.h" |
| 153 | #include "instrumentation/syscalls/headers/syscalls_pointers.h" |
| 154 | }; |
| 155 | |
| 156 | #undef TRACE_SYSCALL_TABLE |
| 157 | #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \ |
| 158 | [ _nr ] = { \ |
| 159 | .func = __event_probe__##compat_##_template, \ |
| 160 | .nrargs = (_nrargs), \ |
| 161 | .fields = __event_fields___##compat_##_template,\ |
| 162 | .desc = &__event_desc___##compat_##_name, \ |
| 163 | }, |
| 164 | |
| 165 | /* Create compatibility syscall table */ |
| 166 | const struct trace_syscall_entry compat_sc_table[] = { |
| 167 | #include "instrumentation/syscalls/headers/compat_syscalls_integers.h" |
| 168 | #include "instrumentation/syscalls/headers/compat_syscalls_pointers.h" |
| 169 | }; |
| 170 | |
| 171 | #undef CREATE_SYSCALL_TABLE |
| 172 | |
| 173 | struct lttng_syscall_filter { |
| 174 | DECLARE_BITMAP(sc, NR_syscalls); |
| 175 | DECLARE_BITMAP(sc_compat, NR_compat_syscalls); |
| 176 | }; |
| 177 | |
| 178 | static void syscall_entry_unknown(struct lttng_event *event, |
| 179 | struct pt_regs *regs, unsigned int id) |
| 180 | { |
| 181 | unsigned long args[UNKNOWN_SYSCALL_NRARGS]; |
| 182 | |
| 183 | syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args); |
| 184 | if (unlikely(is_compat_task())) |
| 185 | __event_probe__compat_sys_unknown(event, id, args); |
| 186 | else |
| 187 | __event_probe__sys_unknown(event, id, args); |
| 188 | } |
| 189 | |
| 190 | void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) |
| 191 | { |
| 192 | struct lttng_channel *chan = __data; |
| 193 | struct lttng_event *event, *unknown_event; |
| 194 | const struct trace_syscall_entry *table, *entry; |
| 195 | size_t table_len; |
| 196 | |
| 197 | if (unlikely(is_compat_task())) { |
| 198 | struct lttng_syscall_filter *filter; |
| 199 | |
| 200 | filter = rcu_dereference(chan->sc_filter); |
| 201 | if (filter) { |
| 202 | if (id >= NR_compat_syscalls |
| 203 | || !test_bit(id, filter->sc_compat)) { |
| 204 | /* System call filtered out. */ |
| 205 | return; |
| 206 | } |
| 207 | } |
| 208 | table = compat_sc_table; |
| 209 | table_len = ARRAY_SIZE(compat_sc_table); |
| 210 | unknown_event = chan->sc_compat_unknown; |
| 211 | } else { |
| 212 | struct lttng_syscall_filter *filter; |
| 213 | |
| 214 | filter = rcu_dereference(chan->sc_filter); |
| 215 | if (filter) { |
| 216 | if (id >= NR_syscalls |
| 217 | || !test_bit(id, filter->sc)) { |
| 218 | /* System call filtered out. */ |
| 219 | return; |
| 220 | } |
| 221 | } |
| 222 | table = sc_table; |
| 223 | table_len = ARRAY_SIZE(sc_table); |
| 224 | unknown_event = chan->sc_unknown; |
| 225 | } |
| 226 | if (unlikely(id >= table_len)) { |
| 227 | syscall_entry_unknown(unknown_event, regs, id); |
| 228 | return; |
| 229 | } |
| 230 | if (unlikely(is_compat_task())) |
| 231 | event = chan->compat_sc_table[id]; |
| 232 | else |
| 233 | event = chan->sc_table[id]; |
| 234 | if (unlikely(!event)) { |
| 235 | syscall_entry_unknown(unknown_event, regs, id); |
| 236 | return; |
| 237 | } |
| 238 | entry = &table[id]; |
| 239 | WARN_ON_ONCE(!entry); |
| 240 | |
| 241 | switch (entry->nrargs) { |
| 242 | case 0: |
| 243 | { |
| 244 | void (*fptr)(void *__data) = entry->func; |
| 245 | |
| 246 | fptr(event); |
| 247 | break; |
| 248 | } |
| 249 | case 1: |
| 250 | { |
| 251 | void (*fptr)(void *__data, unsigned long arg0) = entry->func; |
| 252 | unsigned long args[1]; |
| 253 | |
| 254 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 255 | fptr(event, args[0]); |
| 256 | break; |
| 257 | } |
| 258 | case 2: |
| 259 | { |
| 260 | void (*fptr)(void *__data, |
| 261 | unsigned long arg0, |
| 262 | unsigned long arg1) = entry->func; |
| 263 | unsigned long args[2]; |
| 264 | |
| 265 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 266 | fptr(event, args[0], args[1]); |
| 267 | break; |
| 268 | } |
| 269 | case 3: |
| 270 | { |
| 271 | void (*fptr)(void *__data, |
| 272 | unsigned long arg0, |
| 273 | unsigned long arg1, |
| 274 | unsigned long arg2) = entry->func; |
| 275 | unsigned long args[3]; |
| 276 | |
| 277 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 278 | fptr(event, args[0], args[1], args[2]); |
| 279 | break; |
| 280 | } |
| 281 | case 4: |
| 282 | { |
| 283 | void (*fptr)(void *__data, |
| 284 | unsigned long arg0, |
| 285 | unsigned long arg1, |
| 286 | unsigned long arg2, |
| 287 | unsigned long arg3) = entry->func; |
| 288 | unsigned long args[4]; |
| 289 | |
| 290 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 291 | fptr(event, args[0], args[1], args[2], args[3]); |
| 292 | break; |
| 293 | } |
| 294 | case 5: |
| 295 | { |
| 296 | void (*fptr)(void *__data, |
| 297 | unsigned long arg0, |
| 298 | unsigned long arg1, |
| 299 | unsigned long arg2, |
| 300 | unsigned long arg3, |
| 301 | unsigned long arg4) = entry->func; |
| 302 | unsigned long args[5]; |
| 303 | |
| 304 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 305 | fptr(event, args[0], args[1], args[2], args[3], args[4]); |
| 306 | break; |
| 307 | } |
| 308 | case 6: |
| 309 | { |
| 310 | void (*fptr)(void *__data, |
| 311 | unsigned long arg0, |
| 312 | unsigned long arg1, |
| 313 | unsigned long arg2, |
| 314 | unsigned long arg3, |
| 315 | unsigned long arg4, |
| 316 | unsigned long arg5) = entry->func; |
| 317 | unsigned long args[6]; |
| 318 | |
| 319 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 320 | fptr(event, args[0], args[1], args[2], |
| 321 | args[3], args[4], args[5]); |
| 322 | break; |
| 323 | } |
| 324 | default: |
| 325 | break; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | /* noinline to diminish caller stack size */ |
| 330 | static |
| 331 | int fill_table(const struct trace_syscall_entry *table, size_t table_len, |
| 332 | struct lttng_event **chan_table, struct lttng_channel *chan, void *filter) |
| 333 | { |
| 334 | const struct lttng_event_desc *desc; |
| 335 | unsigned int i; |
| 336 | |
| 337 | /* Allocate events for each syscall, insert into table */ |
| 338 | for (i = 0; i < table_len; i++) { |
| 339 | struct lttng_kernel_event ev; |
| 340 | desc = table[i].desc; |
| 341 | |
| 342 | if (!desc) { |
| 343 | /* Unknown syscall */ |
| 344 | continue; |
| 345 | } |
| 346 | /* |
| 347 | * Skip those already populated by previous failed |
| 348 | * register for this channel. |
| 349 | */ |
| 350 | if (chan_table[i]) |
| 351 | continue; |
| 352 | memset(&ev, 0, sizeof(ev)); |
| 353 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 354 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 355 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 356 | chan_table[i] = lttng_event_create(chan, &ev, filter, |
| 357 | desc); |
| 358 | WARN_ON_ONCE(!chan_table[i]); |
| 359 | if (IS_ERR(chan_table[i])) { |
| 360 | /* |
| 361 | * If something goes wrong in event registration |
| 362 | * after the first one, we have no choice but to |
| 363 | * leave the previous events in there, until |
| 364 | * deleted by session teardown. |
| 365 | */ |
| 366 | return PTR_ERR(chan_table[i]); |
| 367 | } |
| 368 | } |
| 369 | return 0; |
| 370 | } |
| 371 | |
| 372 | int lttng_syscalls_register(struct lttng_channel *chan, void *filter) |
| 373 | { |
| 374 | struct lttng_kernel_event ev; |
| 375 | int ret; |
| 376 | |
| 377 | wrapper_vmalloc_sync_all(); |
| 378 | |
| 379 | if (!chan->sc_table) { |
| 380 | /* create syscall table mapping syscall to events */ |
| 381 | chan->sc_table = kzalloc(sizeof(struct lttng_event *) |
| 382 | * ARRAY_SIZE(sc_table), GFP_KERNEL); |
| 383 | if (!chan->sc_table) |
| 384 | return -ENOMEM; |
| 385 | } |
| 386 | |
| 387 | #ifdef CONFIG_COMPAT |
| 388 | if (!chan->compat_sc_table) { |
| 389 | /* create syscall table mapping compat syscall to events */ |
| 390 | chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *) |
| 391 | * ARRAY_SIZE(compat_sc_table), GFP_KERNEL); |
| 392 | if (!chan->compat_sc_table) |
| 393 | return -ENOMEM; |
| 394 | } |
| 395 | #endif |
| 396 | if (!chan->sc_unknown) { |
| 397 | const struct lttng_event_desc *desc = |
| 398 | &__event_desc___sys_unknown; |
| 399 | |
| 400 | memset(&ev, 0, sizeof(ev)); |
| 401 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 402 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 403 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 404 | chan->sc_unknown = lttng_event_create(chan, &ev, filter, |
| 405 | desc); |
| 406 | WARN_ON_ONCE(!chan->sc_unknown); |
| 407 | if (IS_ERR(chan->sc_unknown)) { |
| 408 | return PTR_ERR(chan->sc_unknown); |
| 409 | } |
| 410 | } |
| 411 | |
| 412 | if (!chan->sc_compat_unknown) { |
| 413 | const struct lttng_event_desc *desc = |
| 414 | &__event_desc___compat_sys_unknown; |
| 415 | |
| 416 | memset(&ev, 0, sizeof(ev)); |
| 417 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 418 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 419 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 420 | chan->sc_compat_unknown = lttng_event_create(chan, &ev, filter, |
| 421 | desc); |
| 422 | WARN_ON_ONCE(!chan->sc_unknown); |
| 423 | if (IS_ERR(chan->sc_compat_unknown)) { |
| 424 | return PTR_ERR(chan->sc_compat_unknown); |
| 425 | } |
| 426 | } |
| 427 | |
| 428 | if (!chan->sc_exit) { |
| 429 | const struct lttng_event_desc *desc = |
| 430 | &__event_desc___exit_syscall; |
| 431 | |
| 432 | memset(&ev, 0, sizeof(ev)); |
| 433 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 434 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 435 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 436 | chan->sc_exit = lttng_event_create(chan, &ev, filter, |
| 437 | desc); |
| 438 | WARN_ON_ONCE(!chan->sc_exit); |
| 439 | if (IS_ERR(chan->sc_exit)) { |
| 440 | return PTR_ERR(chan->sc_exit); |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | ret = fill_table(sc_table, ARRAY_SIZE(sc_table), |
| 445 | chan->sc_table, chan, filter); |
| 446 | if (ret) |
| 447 | return ret; |
| 448 | #ifdef CONFIG_COMPAT |
| 449 | ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table), |
| 450 | chan->compat_sc_table, chan, filter); |
| 451 | if (ret) |
| 452 | return ret; |
| 453 | #endif |
| 454 | if (!chan->sys_enter_registered) { |
| 455 | ret = lttng_wrapper_tracepoint_probe_register("sys_enter", |
| 456 | (void *) syscall_entry_probe, chan); |
| 457 | if (ret) |
| 458 | return ret; |
| 459 | chan->sys_enter_registered = 1; |
| 460 | } |
| 461 | /* |
| 462 | * We change the name of sys_exit tracepoint due to namespace |
| 463 | * conflict with sys_exit syscall entry. |
| 464 | */ |
| 465 | if (!chan->sys_exit_registered) { |
| 466 | ret = lttng_wrapper_tracepoint_probe_register("sys_exit", |
| 467 | (void *) __event_probe__exit_syscall, |
| 468 | chan->sc_exit); |
| 469 | if (ret) { |
| 470 | WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter", |
| 471 | (void *) syscall_entry_probe, chan)); |
| 472 | return ret; |
| 473 | } |
| 474 | chan->sys_exit_registered = 1; |
| 475 | } |
| 476 | return ret; |
| 477 | } |
| 478 | |
| 479 | /* |
| 480 | * Only called at session destruction. |
| 481 | */ |
| 482 | int lttng_syscalls_unregister(struct lttng_channel *chan) |
| 483 | { |
| 484 | int ret; |
| 485 | |
| 486 | if (!chan->sc_table) |
| 487 | return 0; |
| 488 | if (chan->sys_enter_registered) { |
| 489 | ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit", |
| 490 | (void *) __event_probe__exit_syscall, |
| 491 | chan->sc_exit); |
| 492 | if (ret) |
| 493 | return ret; |
| 494 | chan->sys_enter_registered = 0; |
| 495 | } |
| 496 | if (chan->sys_exit_registered) { |
| 497 | ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter", |
| 498 | (void *) syscall_entry_probe, chan); |
| 499 | if (ret) |
| 500 | return ret; |
| 501 | chan->sys_exit_registered = 0; |
| 502 | } |
| 503 | /* lttng_event destroy will be performed by lttng_session_destroy() */ |
| 504 | kfree(chan->sc_table); |
| 505 | #ifdef CONFIG_COMPAT |
| 506 | kfree(chan->compat_sc_table); |
| 507 | #endif |
| 508 | kfree(chan->sc_filter); |
| 509 | return 0; |
| 510 | } |
| 511 | |
| 512 | static |
| 513 | int get_syscall_nr(const char *syscall_name) |
| 514 | { |
| 515 | int syscall_nr = -1; |
| 516 | int i; |
| 517 | |
| 518 | for (i = 0; i < ARRAY_SIZE(sc_table); i++) { |
| 519 | const struct trace_syscall_entry *entry; |
| 520 | |
| 521 | entry = &sc_table[i]; |
| 522 | if (!entry->desc) |
| 523 | continue; |
| 524 | if (!strcmp(syscall_name, entry->desc->name)) { |
| 525 | syscall_nr = i; |
| 526 | break; |
| 527 | } |
| 528 | } |
| 529 | return syscall_nr; |
| 530 | } |
| 531 | |
| 532 | static |
| 533 | int get_compat_syscall_nr(const char *syscall_name) |
| 534 | { |
| 535 | int syscall_nr = -1; |
| 536 | int i; |
| 537 | |
| 538 | for (i = 0; i < ARRAY_SIZE(compat_sc_table); i++) { |
| 539 | const struct trace_syscall_entry *entry; |
| 540 | |
| 541 | entry = &compat_sc_table[i]; |
| 542 | if (!entry->desc) |
| 543 | continue; |
| 544 | if (!strcmp(syscall_name, entry->desc->name)) { |
| 545 | syscall_nr = i; |
| 546 | break; |
| 547 | } |
| 548 | } |
| 549 | return syscall_nr; |
| 550 | } |
| 551 | |
| 552 | int lttng_syscall_filter_enable(struct lttng_channel *chan, |
| 553 | const char *name) |
| 554 | { |
| 555 | int syscall_nr, compat_syscall_nr, ret; |
| 556 | struct lttng_syscall_filter *filter; |
| 557 | |
| 558 | WARN_ON_ONCE(!chan->sc_table); |
| 559 | |
| 560 | if (!name) { |
| 561 | /* Enable all system calls by removing filter */ |
| 562 | if (chan->sc_filter) { |
| 563 | filter = chan->sc_filter; |
| 564 | rcu_assign_pointer(chan->sc_filter, NULL); |
| 565 | synchronize_trace(); |
| 566 | kfree(filter); |
| 567 | } |
| 568 | chan->syscall_all = 1; |
| 569 | return 0; |
| 570 | } |
| 571 | |
| 572 | if (!chan->sc_filter) { |
| 573 | if (chan->syscall_all) { |
| 574 | /* |
| 575 | * All syscalls are already enabled. |
| 576 | */ |
| 577 | return -EEXIST; |
| 578 | } |
| 579 | filter = kzalloc(sizeof(struct lttng_syscall_filter), |
| 580 | GFP_KERNEL); |
| 581 | if (!filter) |
| 582 | return -ENOMEM; |
| 583 | } else { |
| 584 | filter = chan->sc_filter; |
| 585 | } |
| 586 | syscall_nr = get_syscall_nr(name); |
| 587 | compat_syscall_nr = get_compat_syscall_nr(name); |
| 588 | if (syscall_nr < 0 && compat_syscall_nr < 0) { |
| 589 | ret = -ENOENT; |
| 590 | goto error; |
| 591 | } |
| 592 | if (syscall_nr >= 0) { |
| 593 | if (test_bit(syscall_nr, filter->sc)) { |
| 594 | ret = -EEXIST; |
| 595 | goto error; |
| 596 | } |
| 597 | bitmap_set(filter->sc, syscall_nr, 1); |
| 598 | } |
| 599 | if (compat_syscall_nr >= 0) { |
| 600 | if (test_bit(compat_syscall_nr, filter->sc_compat)) { |
| 601 | ret = -EEXIST; |
| 602 | goto error; |
| 603 | } |
| 604 | bitmap_set(filter->sc_compat, compat_syscall_nr, 1); |
| 605 | } |
| 606 | if (!chan->sc_filter) |
| 607 | rcu_assign_pointer(chan->sc_filter, filter); |
| 608 | return 0; |
| 609 | |
| 610 | error: |
| 611 | if (!chan->sc_filter) |
| 612 | kfree(filter); |
| 613 | return ret; |
| 614 | } |
| 615 | |
| 616 | int lttng_syscall_filter_disable(struct lttng_channel *chan, |
| 617 | const char *name) |
| 618 | { |
| 619 | int syscall_nr, compat_syscall_nr, ret; |
| 620 | struct lttng_syscall_filter *filter; |
| 621 | |
| 622 | WARN_ON_ONCE(!chan->sc_table); |
| 623 | |
| 624 | if (!chan->sc_filter) { |
| 625 | filter = kzalloc(sizeof(struct lttng_syscall_filter), |
| 626 | GFP_KERNEL); |
| 627 | if (!filter) |
| 628 | return -ENOMEM; |
| 629 | /* Trace all system calls, then apply disable. */ |
| 630 | bitmap_set(filter->sc, 0, NR_syscalls); |
| 631 | bitmap_set(filter->sc_compat, 0, NR_compat_syscalls); |
| 632 | } else { |
| 633 | filter = chan->sc_filter; |
| 634 | } |
| 635 | |
| 636 | syscall_nr = get_syscall_nr(name); |
| 637 | compat_syscall_nr = get_compat_syscall_nr(name); |
| 638 | if (syscall_nr < 0 && compat_syscall_nr < 0) { |
| 639 | ret = -ENOENT; |
| 640 | goto error; |
| 641 | } |
| 642 | if (syscall_nr >= 0) { |
| 643 | if (!test_bit(syscall_nr, chan->sc_filter->sc)) { |
| 644 | ret = -EEXIST; |
| 645 | goto error; |
| 646 | } |
| 647 | bitmap_clear(chan->sc_filter->sc, syscall_nr, 1); |
| 648 | } |
| 649 | if (compat_syscall_nr >= 0) { |
| 650 | if (!test_bit(compat_syscall_nr, chan->sc_filter->sc_compat)) { |
| 651 | ret = -EEXIST; |
| 652 | goto error; |
| 653 | } |
| 654 | bitmap_clear(chan->sc_filter->sc_compat, compat_syscall_nr, 1); |
| 655 | } |
| 656 | if (!chan->sc_filter) |
| 657 | rcu_assign_pointer(chan->sc_filter, filter); |
| 658 | chan->syscall_all = 0; |
| 659 | return 0; |
| 660 | |
| 661 | error: |
| 662 | if (!chan->sc_filter) |
| 663 | kfree(filter); |
| 664 | return ret; |
| 665 | } |