| 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 <asm/ptrace.h> |
| 28 | #include <asm/syscall.h> |
| 29 | |
| 30 | #include "wrapper/tracepoint.h" |
| 31 | #include "lttng-events.h" |
| 32 | |
| 33 | #ifndef CONFIG_COMPAT |
| 34 | # ifndef is_compat_task |
| 35 | # define is_compat_task() (0) |
| 36 | # endif |
| 37 | #endif |
| 38 | |
| 39 | static |
| 40 | void syscall_entry_probe(void *__data, struct pt_regs *regs, long id); |
| 41 | |
| 42 | /* |
| 43 | * Forward declarations for old kernels. |
| 44 | */ |
| 45 | struct mmsghdr; |
| 46 | struct rlimit64; |
| 47 | struct oldold_utsname; |
| 48 | struct old_utsname; |
| 49 | struct sel_arg_struct; |
| 50 | struct mmap_arg_struct; |
| 51 | struct file_handle; |
| 52 | |
| 53 | /* |
| 54 | * Take care of NOARGS not supported by mainline. |
| 55 | */ |
| 56 | #define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print) |
| 57 | #define DEFINE_EVENT_NOARGS(template, name) |
| 58 | #define TRACE_EVENT_NOARGS(name, struct, assign, print) |
| 59 | |
| 60 | /* |
| 61 | * Create LTTng tracepoint probes. |
| 62 | */ |
| 63 | #define LTTNG_PACKAGE_BUILD |
| 64 | #define CREATE_TRACE_POINTS |
| 65 | #define TP_MODULE_NOINIT |
| 66 | #define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers |
| 67 | |
| 68 | #define PARAMS(args...) args |
| 69 | |
| 70 | /* Hijack probe callback for system calls */ |
| 71 | #undef TP_PROBE_CB |
| 72 | #define TP_PROBE_CB(_template) &syscall_entry_probe |
| 73 | #define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \ |
| 74 | TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\ |
| 75 | PARAMS(_struct), PARAMS(_assign), PARAMS(_printk)) |
| 76 | #define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \ |
| 77 | DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\ |
| 78 | PARAMS(_printk)) |
| 79 | #define SC_DEFINE_EVENT_NOARGS(_template, _name) \ |
| 80 | DEFINE_EVENT_NOARGS(_template, _name) |
| 81 | #undef TRACE_SYSTEM |
| 82 | #define TRACE_SYSTEM syscalls_integers |
| 83 | #include "instrumentation/syscalls/headers/syscalls_integers.h" |
| 84 | #undef TRACE_SYSTEM |
| 85 | #define TRACE_SYSTEM syscalls_pointers |
| 86 | #include "instrumentation/syscalls/headers/syscalls_pointers.h" |
| 87 | #undef TRACE_SYSTEM |
| 88 | #undef SC_TRACE_EVENT |
| 89 | #undef SC_DECLARE_EVENT_CLASS_NOARGS |
| 90 | #undef SC_DEFINE_EVENT_NOARGS |
| 91 | |
| 92 | #define TRACE_SYSTEM syscalls_unknown |
| 93 | #include "instrumentation/syscalls/headers/syscalls_unknown.h" |
| 94 | #undef TRACE_SYSTEM |
| 95 | |
| 96 | /* For compat syscalls */ |
| 97 | #undef _TRACE_SYSCALLS_integers_H |
| 98 | #undef _TRACE_SYSCALLS_pointers_H |
| 99 | |
| 100 | /* Hijack probe callback for system calls */ |
| 101 | #undef TP_PROBE_CB |
| 102 | #define TP_PROBE_CB(_template) &syscall_entry_probe |
| 103 | #define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \ |
| 104 | TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args), \ |
| 105 | PARAMS(_struct), PARAMS(_assign), \ |
| 106 | PARAMS(_printk)) |
| 107 | #define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \ |
| 108 | DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct), \ |
| 109 | PARAMS(_assign), PARAMS(_printk)) |
| 110 | #define SC_DEFINE_EVENT_NOARGS(_template, _name) \ |
| 111 | DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name) |
| 112 | #define TRACE_SYSTEM compat_syscalls_integers |
| 113 | #include "instrumentation/syscalls/headers/compat_syscalls_integers.h" |
| 114 | #undef TRACE_SYSTEM |
| 115 | #define TRACE_SYSTEM compat_syscalls_pointers |
| 116 | #include "instrumentation/syscalls/headers/compat_syscalls_pointers.h" |
| 117 | #undef TRACE_SYSTEM |
| 118 | #undef SC_TRACE_EVENT |
| 119 | #undef SC_DECLARE_EVENT_CLASS_NOARGS |
| 120 | #undef SC_DEFINE_EVENT_NOARGS |
| 121 | #undef TP_PROBE_CB |
| 122 | |
| 123 | #undef TP_MODULE_NOINIT |
| 124 | #undef LTTNG_PACKAGE_BUILD |
| 125 | #undef CREATE_TRACE_POINTS |
| 126 | |
| 127 | struct trace_syscall_entry { |
| 128 | void *func; |
| 129 | const struct lttng_event_desc *desc; |
| 130 | const struct lttng_event_field *fields; |
| 131 | unsigned int nrargs; |
| 132 | }; |
| 133 | |
| 134 | #define CREATE_SYSCALL_TABLE |
| 135 | |
| 136 | #undef TRACE_SYSCALL_TABLE |
| 137 | #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \ |
| 138 | [ _nr ] = { \ |
| 139 | .func = __event_probe__##_template, \ |
| 140 | .nrargs = (_nrargs), \ |
| 141 | .fields = __event_fields___##_template, \ |
| 142 | .desc = &__event_desc___##_name, \ |
| 143 | }, |
| 144 | |
| 145 | static const struct trace_syscall_entry sc_table[] = { |
| 146 | #include "instrumentation/syscalls/headers/syscalls_integers.h" |
| 147 | #include "instrumentation/syscalls/headers/syscalls_pointers.h" |
| 148 | }; |
| 149 | |
| 150 | #undef TRACE_SYSCALL_TABLE |
| 151 | #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \ |
| 152 | [ _nr ] = { \ |
| 153 | .func = __event_probe__##compat_##_template, \ |
| 154 | .nrargs = (_nrargs), \ |
| 155 | .fields = __event_fields___##compat_##_template,\ |
| 156 | .desc = &__event_desc___##compat_##_name, \ |
| 157 | }, |
| 158 | |
| 159 | /* Create compatibility syscall table */ |
| 160 | const struct trace_syscall_entry compat_sc_table[] = { |
| 161 | #include "instrumentation/syscalls/headers/compat_syscalls_integers.h" |
| 162 | #include "instrumentation/syscalls/headers/compat_syscalls_pointers.h" |
| 163 | }; |
| 164 | |
| 165 | #undef CREATE_SYSCALL_TABLE |
| 166 | |
| 167 | static void syscall_entry_unknown(struct lttng_event *event, |
| 168 | struct pt_regs *regs, unsigned int id) |
| 169 | { |
| 170 | unsigned long args[UNKNOWN_SYSCALL_NRARGS]; |
| 171 | |
| 172 | syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args); |
| 173 | if (unlikely(is_compat_task())) |
| 174 | __event_probe__compat_sys_unknown(event, id, args); |
| 175 | else |
| 176 | __event_probe__sys_unknown(event, id, args); |
| 177 | } |
| 178 | |
| 179 | void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) |
| 180 | { |
| 181 | struct lttng_channel *chan = __data; |
| 182 | struct lttng_event *event, *unknown_event; |
| 183 | const struct trace_syscall_entry *table, *entry; |
| 184 | size_t table_len; |
| 185 | |
| 186 | if (unlikely(is_compat_task())) { |
| 187 | table = compat_sc_table; |
| 188 | table_len = ARRAY_SIZE(compat_sc_table); |
| 189 | unknown_event = chan->sc_compat_unknown; |
| 190 | } else { |
| 191 | table = sc_table; |
| 192 | table_len = ARRAY_SIZE(sc_table); |
| 193 | unknown_event = chan->sc_unknown; |
| 194 | } |
| 195 | if (unlikely(id >= table_len)) { |
| 196 | syscall_entry_unknown(unknown_event, regs, id); |
| 197 | return; |
| 198 | } |
| 199 | if (unlikely(is_compat_task())) |
| 200 | event = chan->compat_sc_table[id]; |
| 201 | else |
| 202 | event = chan->sc_table[id]; |
| 203 | if (unlikely(!event)) { |
| 204 | syscall_entry_unknown(unknown_event, regs, id); |
| 205 | return; |
| 206 | } |
| 207 | entry = &table[id]; |
| 208 | WARN_ON_ONCE(!entry); |
| 209 | |
| 210 | switch (entry->nrargs) { |
| 211 | case 0: |
| 212 | { |
| 213 | void (*fptr)(void *__data) = entry->func; |
| 214 | |
| 215 | fptr(event); |
| 216 | break; |
| 217 | } |
| 218 | case 1: |
| 219 | { |
| 220 | void (*fptr)(void *__data, unsigned long arg0) = entry->func; |
| 221 | unsigned long args[1]; |
| 222 | |
| 223 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 224 | fptr(event, args[0]); |
| 225 | break; |
| 226 | } |
| 227 | case 2: |
| 228 | { |
| 229 | void (*fptr)(void *__data, |
| 230 | unsigned long arg0, |
| 231 | unsigned long arg1) = entry->func; |
| 232 | unsigned long args[2]; |
| 233 | |
| 234 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 235 | fptr(event, args[0], args[1]); |
| 236 | break; |
| 237 | } |
| 238 | case 3: |
| 239 | { |
| 240 | void (*fptr)(void *__data, |
| 241 | unsigned long arg0, |
| 242 | unsigned long arg1, |
| 243 | unsigned long arg2) = entry->func; |
| 244 | unsigned long args[3]; |
| 245 | |
| 246 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 247 | fptr(event, args[0], args[1], args[2]); |
| 248 | break; |
| 249 | } |
| 250 | case 4: |
| 251 | { |
| 252 | void (*fptr)(void *__data, |
| 253 | unsigned long arg0, |
| 254 | unsigned long arg1, |
| 255 | unsigned long arg2, |
| 256 | unsigned long arg3) = entry->func; |
| 257 | unsigned long args[4]; |
| 258 | |
| 259 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 260 | fptr(event, args[0], args[1], args[2], args[3]); |
| 261 | break; |
| 262 | } |
| 263 | case 5: |
| 264 | { |
| 265 | void (*fptr)(void *__data, |
| 266 | unsigned long arg0, |
| 267 | unsigned long arg1, |
| 268 | unsigned long arg2, |
| 269 | unsigned long arg3, |
| 270 | unsigned long arg4) = entry->func; |
| 271 | unsigned long args[5]; |
| 272 | |
| 273 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 274 | fptr(event, args[0], args[1], args[2], args[3], args[4]); |
| 275 | break; |
| 276 | } |
| 277 | case 6: |
| 278 | { |
| 279 | void (*fptr)(void *__data, |
| 280 | unsigned long arg0, |
| 281 | unsigned long arg1, |
| 282 | unsigned long arg2, |
| 283 | unsigned long arg3, |
| 284 | unsigned long arg4, |
| 285 | unsigned long arg5) = entry->func; |
| 286 | unsigned long args[6]; |
| 287 | |
| 288 | syscall_get_arguments(current, regs, 0, entry->nrargs, args); |
| 289 | fptr(event, args[0], args[1], args[2], |
| 290 | args[3], args[4], args[5]); |
| 291 | break; |
| 292 | } |
| 293 | default: |
| 294 | break; |
| 295 | } |
| 296 | } |
| 297 | |
| 298 | /* noinline to diminish caller stack size */ |
| 299 | static |
| 300 | int fill_table(const struct trace_syscall_entry *table, size_t table_len, |
| 301 | struct lttng_event **chan_table, struct lttng_channel *chan, void *filter) |
| 302 | { |
| 303 | const struct lttng_event_desc *desc; |
| 304 | unsigned int i; |
| 305 | |
| 306 | /* Allocate events for each syscall, insert into table */ |
| 307 | for (i = 0; i < table_len; i++) { |
| 308 | struct lttng_kernel_event ev; |
| 309 | desc = table[i].desc; |
| 310 | |
| 311 | if (!desc) { |
| 312 | /* Unknown syscall */ |
| 313 | continue; |
| 314 | } |
| 315 | /* |
| 316 | * Skip those already populated by previous failed |
| 317 | * register for this channel. |
| 318 | */ |
| 319 | if (chan_table[i]) |
| 320 | continue; |
| 321 | memset(&ev, 0, sizeof(ev)); |
| 322 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 323 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 324 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 325 | chan_table[i] = lttng_event_create(chan, &ev, filter, |
| 326 | desc); |
| 327 | WARN_ON_ONCE(!chan_table[i]); |
| 328 | if (IS_ERR(chan_table[i])) { |
| 329 | /* |
| 330 | * If something goes wrong in event registration |
| 331 | * after the first one, we have no choice but to |
| 332 | * leave the previous events in there, until |
| 333 | * deleted by session teardown. |
| 334 | */ |
| 335 | return PTR_ERR(chan_table[i]); |
| 336 | } |
| 337 | } |
| 338 | return 0; |
| 339 | } |
| 340 | |
| 341 | int lttng_syscalls_register(struct lttng_channel *chan, void *filter) |
| 342 | { |
| 343 | struct lttng_kernel_event ev; |
| 344 | int ret; |
| 345 | |
| 346 | wrapper_vmalloc_sync_all(); |
| 347 | |
| 348 | if (!chan->sc_table) { |
| 349 | /* create syscall table mapping syscall to events */ |
| 350 | chan->sc_table = kzalloc(sizeof(struct lttng_event *) |
| 351 | * ARRAY_SIZE(sc_table), GFP_KERNEL); |
| 352 | if (!chan->sc_table) |
| 353 | return -ENOMEM; |
| 354 | } |
| 355 | |
| 356 | #ifdef CONFIG_COMPAT |
| 357 | if (!chan->compat_sc_table) { |
| 358 | /* create syscall table mapping compat syscall to events */ |
| 359 | chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *) |
| 360 | * ARRAY_SIZE(compat_sc_table), GFP_KERNEL); |
| 361 | if (!chan->compat_sc_table) |
| 362 | return -ENOMEM; |
| 363 | } |
| 364 | #endif |
| 365 | if (!chan->sc_unknown) { |
| 366 | const struct lttng_event_desc *desc = |
| 367 | &__event_desc___sys_unknown; |
| 368 | |
| 369 | memset(&ev, 0, sizeof(ev)); |
| 370 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 371 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 372 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 373 | chan->sc_unknown = lttng_event_create(chan, &ev, filter, |
| 374 | desc); |
| 375 | WARN_ON_ONCE(!chan->sc_unknown); |
| 376 | if (IS_ERR(chan->sc_unknown)) { |
| 377 | return PTR_ERR(chan->sc_unknown); |
| 378 | } |
| 379 | } |
| 380 | |
| 381 | if (!chan->sc_compat_unknown) { |
| 382 | const struct lttng_event_desc *desc = |
| 383 | &__event_desc___compat_sys_unknown; |
| 384 | |
| 385 | memset(&ev, 0, sizeof(ev)); |
| 386 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 387 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 388 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 389 | chan->sc_compat_unknown = lttng_event_create(chan, &ev, filter, |
| 390 | desc); |
| 391 | WARN_ON_ONCE(!chan->sc_unknown); |
| 392 | if (IS_ERR(chan->sc_compat_unknown)) { |
| 393 | return PTR_ERR(chan->sc_compat_unknown); |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | if (!chan->sc_exit) { |
| 398 | const struct lttng_event_desc *desc = |
| 399 | &__event_desc___exit_syscall; |
| 400 | |
| 401 | memset(&ev, 0, sizeof(ev)); |
| 402 | strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN); |
| 403 | ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0'; |
| 404 | ev.instrumentation = LTTNG_KERNEL_NOOP; |
| 405 | chan->sc_exit = lttng_event_create(chan, &ev, filter, |
| 406 | desc); |
| 407 | WARN_ON_ONCE(!chan->sc_exit); |
| 408 | if (IS_ERR(chan->sc_exit)) { |
| 409 | return PTR_ERR(chan->sc_exit); |
| 410 | } |
| 411 | } |
| 412 | |
| 413 | ret = fill_table(sc_table, ARRAY_SIZE(sc_table), |
| 414 | chan->sc_table, chan, filter); |
| 415 | if (ret) |
| 416 | return ret; |
| 417 | #ifdef CONFIG_COMPAT |
| 418 | ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table), |
| 419 | chan->compat_sc_table, chan, filter); |
| 420 | if (ret) |
| 421 | return ret; |
| 422 | #endif |
| 423 | ret = lttng_wrapper_tracepoint_probe_register("sys_enter", |
| 424 | (void *) syscall_entry_probe, chan); |
| 425 | if (ret) |
| 426 | return ret; |
| 427 | /* |
| 428 | * We change the name of sys_exit tracepoint due to namespace |
| 429 | * conflict with sys_exit syscall entry. |
| 430 | */ |
| 431 | ret = lttng_wrapper_tracepoint_probe_register("sys_exit", |
| 432 | (void *) __event_probe__exit_syscall, |
| 433 | chan->sc_exit); |
| 434 | if (ret) { |
| 435 | WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter", |
| 436 | (void *) syscall_entry_probe, chan)); |
| 437 | } |
| 438 | return ret; |
| 439 | } |
| 440 | |
| 441 | /* |
| 442 | * Only called at session destruction. |
| 443 | */ |
| 444 | int lttng_syscalls_unregister(struct lttng_channel *chan) |
| 445 | { |
| 446 | int ret; |
| 447 | |
| 448 | if (!chan->sc_table) |
| 449 | return 0; |
| 450 | ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit", |
| 451 | (void *) __event_probe__exit_syscall, |
| 452 | chan->sc_exit); |
| 453 | if (ret) |
| 454 | return ret; |
| 455 | ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter", |
| 456 | (void *) syscall_entry_probe, chan); |
| 457 | if (ret) |
| 458 | return ret; |
| 459 | /* lttng_event destroy will be performed by lttng_session_destroy() */ |
| 460 | kfree(chan->sc_table); |
| 461 | #ifdef CONFIG_COMPAT |
| 462 | kfree(chan->compat_sc_table); |
| 463 | #endif |
| 464 | return 0; |
| 465 | } |