Roland McGrath | 88ac292 | 2008-07-25 19:45:43 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Tracing hooks |
| 3 | * |
| 4 | * Copyright (C) 2008 Red Hat, Inc. All rights reserved. |
| 5 | * |
| 6 | * This copyrighted material is made available to anyone wishing to use, |
| 7 | * modify, copy, or redistribute it subject to the terms and conditions |
| 8 | * of the GNU General Public License v.2. |
| 9 | * |
| 10 | * This file defines hook entry points called by core code where |
| 11 | * user tracing/debugging support might need to do something. These |
| 12 | * entry points are called tracehook_*(). Each hook declared below |
| 13 | * has a detailed kerneldoc comment giving the context (locking et |
| 14 | * al) from which it is called, and the meaning of its return value. |
| 15 | * |
| 16 | * Each function here typically has only one call site, so it is ok |
| 17 | * to have some nontrivial tracehook_*() inlines. In all cases, the |
| 18 | * fast path when no tracing is enabled should be very short. |
| 19 | * |
| 20 | * The purpose of this file and the tracehook_* layer is to consolidate |
| 21 | * the interface that the kernel core and arch code uses to enable any |
| 22 | * user debugging or tracing facility (such as ptrace). The interfaces |
| 23 | * here are carefully documented so that maintainers of core and arch |
| 24 | * code do not need to think about the implementation details of the |
| 25 | * tracing facilities. Likewise, maintainers of the tracing code do not |
| 26 | * need to understand all the calling core or arch code in detail, just |
| 27 | * documented circumstances of each call, such as locking conditions. |
| 28 | * |
| 29 | * If the calling core code changes so that locking is different, then |
| 30 | * it is ok to change the interface documented here. The maintainer of |
| 31 | * core code changing should notify the maintainers of the tracing code |
| 32 | * that they need to work out the change. |
| 33 | * |
| 34 | * Some tracehook_*() inlines take arguments that the current tracing |
| 35 | * implementations might not necessarily use. These function signatures |
| 36 | * are chosen to pass in all the information that is on hand in the |
| 37 | * caller and might conceivably be relevant to a tracer, so that the |
| 38 | * core code won't have to be updated when tracing adds more features. |
| 39 | * If a call site changes so that some of those parameters are no longer |
| 40 | * already on hand without extra work, then the tracehook_* interface |
| 41 | * can change so there is no make-work burden on the core code. The |
| 42 | * maintainer of core code changing should notify the maintainers of the |
| 43 | * tracing code that they need to work out the change. |
| 44 | */ |
| 45 | |
| 46 | #ifndef _LINUX_TRACEHOOK_H |
| 47 | #define _LINUX_TRACEHOOK_H 1 |
| 48 | |
| 49 | #include <linux/sched.h> |
| 50 | #include <linux/ptrace.h> |
Roland McGrath | 6341c39 | 2008-07-25 19:45:44 -0700 | [diff] [blame] | 51 | #include <linux/security.h> |
| 52 | struct linux_binprm; |
| 53 | |
| 54 | /** |
Roland McGrath | fa8e26c | 2008-07-25 19:45:50 -0700 | [diff] [blame] | 55 | * tracehook_expect_breakpoints - guess if task memory might be touched |
| 56 | * @task: current task, making a new mapping |
| 57 | * |
| 58 | * Return nonzero if @task is expected to want breakpoint insertion in |
| 59 | * its memory at some point. A zero return is no guarantee it won't |
| 60 | * be done, but this is a hint that it's known to be likely. |
| 61 | * |
| 62 | * May be called with @task->mm->mmap_sem held for writing. |
| 63 | */ |
| 64 | static inline int tracehook_expect_breakpoints(struct task_struct *task) |
| 65 | { |
| 66 | return (task_ptrace(task) & PT_PTRACED) != 0; |
| 67 | } |
| 68 | |
Roland McGrath | 283d755 | 2008-07-25 19:45:52 -0700 | [diff] [blame] | 69 | /* |
| 70 | * ptrace report for syscall entry and exit looks identical. |
| 71 | */ |
| 72 | static inline void ptrace_report_syscall(struct pt_regs *regs) |
| 73 | { |
| 74 | int ptrace = task_ptrace(current); |
| 75 | |
| 76 | if (!(ptrace & PT_PTRACED)) |
| 77 | return; |
| 78 | |
| 79 | ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); |
| 80 | |
| 81 | /* |
| 82 | * this isn't the same as continuing with a signal, but it will do |
| 83 | * for normal use. strace only continues with a signal if the |
| 84 | * stopping signal is not SIGTRAP. -brl |
| 85 | */ |
| 86 | if (current->exit_code) { |
| 87 | send_sig(current->exit_code, current, 1); |
| 88 | current->exit_code = 0; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * tracehook_report_syscall_entry - task is about to attempt a system call |
| 94 | * @regs: user register state of current task |
| 95 | * |
| 96 | * This will be called if %TIF_SYSCALL_TRACE has been set, when the |
| 97 | * current task has just entered the kernel for a system call. |
| 98 | * Full user register state is available here. Changing the values |
| 99 | * in @regs can affect the system call number and arguments to be tried. |
| 100 | * It is safe to block here, preventing the system call from beginning. |
| 101 | * |
| 102 | * Returns zero normally, or nonzero if the calling arch code should abort |
| 103 | * the system call. That must prevent normal entry so no system call is |
| 104 | * made. If @task ever returns to user mode after this, its register state |
| 105 | * is unspecified, but should be something harmless like an %ENOSYS error |
Roland McGrath | 828c365 | 2008-07-25 19:45:57 -0700 | [diff] [blame] | 106 | * return. It should preserve enough information so that syscall_rollback() |
| 107 | * can work (see asm-generic/syscall.h). |
Roland McGrath | 283d755 | 2008-07-25 19:45:52 -0700 | [diff] [blame] | 108 | * |
| 109 | * Called without locks, just after entering kernel mode. |
| 110 | */ |
| 111 | static inline __must_check int tracehook_report_syscall_entry( |
| 112 | struct pt_regs *regs) |
| 113 | { |
| 114 | ptrace_report_syscall(regs); |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * tracehook_report_syscall_exit - task has just finished a system call |
| 120 | * @regs: user register state of current task |
| 121 | * @step: nonzero if simulating single-step or block-step |
| 122 | * |
| 123 | * This will be called if %TIF_SYSCALL_TRACE has been set, when the |
| 124 | * current task has just finished an attempted system call. Full |
| 125 | * user register state is available here. It is safe to block here, |
| 126 | * preventing signals from being processed. |
| 127 | * |
| 128 | * If @step is nonzero, this report is also in lieu of the normal |
| 129 | * trap that would follow the system call instruction because |
| 130 | * user_enable_block_step() or user_enable_single_step() was used. |
| 131 | * In this case, %TIF_SYSCALL_TRACE might not be set. |
| 132 | * |
| 133 | * Called without locks, just before checking for pending signals. |
| 134 | */ |
| 135 | static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) |
| 136 | { |
| 137 | ptrace_report_syscall(regs); |
| 138 | } |
| 139 | |
Roland McGrath | fa8e26c | 2008-07-25 19:45:50 -0700 | [diff] [blame] | 140 | /** |
Roland McGrath | 6341c39 | 2008-07-25 19:45:44 -0700 | [diff] [blame] | 141 | * tracehook_unsafe_exec - check for exec declared unsafe due to tracing |
| 142 | * @task: current task doing exec |
| 143 | * |
| 144 | * Return %LSM_UNSAFE_* bits applied to an exec because of tracing. |
| 145 | * |
| 146 | * Called with task_lock() held on @task. |
| 147 | */ |
| 148 | static inline int tracehook_unsafe_exec(struct task_struct *task) |
| 149 | { |
| 150 | int unsafe = 0; |
| 151 | int ptrace = task_ptrace(task); |
| 152 | if (ptrace & PT_PTRACED) { |
| 153 | if (ptrace & PT_PTRACE_CAP) |
| 154 | unsafe |= LSM_UNSAFE_PTRACE_CAP; |
| 155 | else |
| 156 | unsafe |= LSM_UNSAFE_PTRACE; |
| 157 | } |
| 158 | return unsafe; |
| 159 | } |
| 160 | |
| 161 | /** |
Roland McGrath | 0d094ef | 2008-07-25 19:45:49 -0700 | [diff] [blame] | 162 | * tracehook_tracer_task - return the task that is tracing the given task |
| 163 | * @tsk: task to consider |
| 164 | * |
| 165 | * Returns NULL if noone is tracing @task, or the &struct task_struct |
| 166 | * pointer to its tracer. |
| 167 | * |
| 168 | * Must called under rcu_read_lock(). The pointer returned might be kept |
| 169 | * live only by RCU. During exec, this may be called with task_lock() |
| 170 | * held on @task, still held from when tracehook_unsafe_exec() was called. |
| 171 | */ |
| 172 | static inline struct task_struct *tracehook_tracer_task(struct task_struct *tsk) |
| 173 | { |
| 174 | if (task_ptrace(tsk) & PT_PTRACED) |
| 175 | return rcu_dereference(tsk->parent); |
| 176 | return NULL; |
| 177 | } |
| 178 | |
| 179 | /** |
Roland McGrath | 6341c39 | 2008-07-25 19:45:44 -0700 | [diff] [blame] | 180 | * tracehook_report_exec - a successful exec was completed |
| 181 | * @fmt: &struct linux_binfmt that performed the exec |
| 182 | * @bprm: &struct linux_binprm containing exec details |
| 183 | * @regs: user-mode register state |
| 184 | * |
| 185 | * An exec just completed, we are shortly going to return to user mode. |
| 186 | * The freshly initialized register state can be seen and changed in @regs. |
| 187 | * The name, file and other pointers in @bprm are still on hand to be |
| 188 | * inspected, but will be freed as soon as this returns. |
| 189 | * |
| 190 | * Called with no locks, but with some kernel resources held live |
| 191 | * and a reference on @fmt->module. |
| 192 | */ |
| 193 | static inline void tracehook_report_exec(struct linux_binfmt *fmt, |
| 194 | struct linux_binprm *bprm, |
| 195 | struct pt_regs *regs) |
| 196 | { |
| 197 | if (!ptrace_event(PT_TRACE_EXEC, PTRACE_EVENT_EXEC, 0) && |
| 198 | unlikely(task_ptrace(current) & PT_PTRACED)) |
| 199 | send_sig(SIGTRAP, current, 0); |
| 200 | } |
Roland McGrath | 88ac292 | 2008-07-25 19:45:43 -0700 | [diff] [blame] | 201 | |
Roland McGrath | 30199f5 | 2008-07-25 19:45:46 -0700 | [diff] [blame] | 202 | /** |
| 203 | * tracehook_report_exit - task has begun to exit |
| 204 | * @exit_code: pointer to value destined for @current->exit_code |
| 205 | * |
| 206 | * @exit_code points to the value passed to do_exit(), which tracing |
| 207 | * might change here. This is almost the first thing in do_exit(), |
| 208 | * before freeing any resources or setting the %PF_EXITING flag. |
| 209 | * |
| 210 | * Called with no locks held. |
| 211 | */ |
| 212 | static inline void tracehook_report_exit(long *exit_code) |
| 213 | { |
| 214 | ptrace_event(PT_TRACE_EXIT, PTRACE_EVENT_EXIT, *exit_code); |
| 215 | } |
| 216 | |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 217 | /** |
| 218 | * tracehook_prepare_clone - prepare for new child to be cloned |
| 219 | * @clone_flags: %CLONE_* flags from clone/fork/vfork system call |
| 220 | * |
| 221 | * This is called before a new user task is to be cloned. |
| 222 | * Its return value will be passed to tracehook_finish_clone(). |
| 223 | * |
| 224 | * Called with no locks held. |
| 225 | */ |
| 226 | static inline int tracehook_prepare_clone(unsigned clone_flags) |
| 227 | { |
| 228 | if (clone_flags & CLONE_UNTRACED) |
| 229 | return 0; |
| 230 | |
| 231 | if (clone_flags & CLONE_VFORK) { |
| 232 | if (current->ptrace & PT_TRACE_VFORK) |
| 233 | return PTRACE_EVENT_VFORK; |
| 234 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { |
| 235 | if (current->ptrace & PT_TRACE_CLONE) |
| 236 | return PTRACE_EVENT_CLONE; |
| 237 | } else if (current->ptrace & PT_TRACE_FORK) |
| 238 | return PTRACE_EVENT_FORK; |
| 239 | |
| 240 | return 0; |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * tracehook_finish_clone - new child created and being attached |
| 245 | * @child: new child task |
| 246 | * @clone_flags: %CLONE_* flags from clone/fork/vfork system call |
Roland McGrath | a9906a1 | 2008-07-26 14:41:26 -0700 | [diff] [blame] | 247 | * @trace: return value from tracehook_prepare_clone() |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 248 | * |
| 249 | * This is called immediately after adding @child to its parent's children list. |
| 250 | * The @trace value is that returned by tracehook_prepare_clone(). |
| 251 | * |
| 252 | * Called with current's siglock and write_lock_irq(&tasklist_lock) held. |
| 253 | */ |
| 254 | static inline void tracehook_finish_clone(struct task_struct *child, |
| 255 | unsigned long clone_flags, int trace) |
| 256 | { |
| 257 | ptrace_init_task(child, (clone_flags & CLONE_PTRACE) || trace); |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * tracehook_report_clone - in parent, new child is about to start running |
Roland McGrath | a9906a1 | 2008-07-26 14:41:26 -0700 | [diff] [blame] | 262 | * @trace: return value from tracehook_prepare_clone() |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 263 | * @regs: parent's user register state |
| 264 | * @clone_flags: flags from parent's system call |
| 265 | * @pid: new child's PID in the parent's namespace |
| 266 | * @child: new child task |
| 267 | * |
Roland McGrath | a9906a1 | 2008-07-26 14:41:26 -0700 | [diff] [blame] | 268 | * Called after a child is set up, but before it has been started |
| 269 | * running. @trace is the value returned by tracehook_prepare_clone(). |
| 270 | * This is not a good place to block, because the child has not started |
| 271 | * yet. Suspend the child here if desired, and then block in |
| 272 | * tracehook_report_clone_complete(). This must prevent the child from |
| 273 | * self-reaping if tracehook_report_clone_complete() uses the @child |
| 274 | * pointer; otherwise it might have died and been released by the time |
| 275 | * tracehook_report_report_clone_complete() is called. |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 276 | * |
| 277 | * Called with no locks held, but the child cannot run until this returns. |
| 278 | */ |
| 279 | static inline void tracehook_report_clone(int trace, struct pt_regs *regs, |
| 280 | unsigned long clone_flags, |
| 281 | pid_t pid, struct task_struct *child) |
| 282 | { |
| 283 | if (unlikely(trace)) { |
| 284 | /* |
| 285 | * The child starts up with an immediate SIGSTOP. |
| 286 | */ |
| 287 | sigaddset(&child->pending.signal, SIGSTOP); |
| 288 | set_tsk_thread_flag(child, TIF_SIGPENDING); |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | /** |
| 293 | * tracehook_report_clone_complete - new child is running |
Roland McGrath | a9906a1 | 2008-07-26 14:41:26 -0700 | [diff] [blame] | 294 | * @trace: return value from tracehook_prepare_clone() |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 295 | * @regs: parent's user register state |
| 296 | * @clone_flags: flags from parent's system call |
| 297 | * @pid: new child's PID in the parent's namespace |
| 298 | * @child: child task, already running |
| 299 | * |
| 300 | * This is called just after the child has started running. This is |
| 301 | * just before the clone/fork syscall returns, or blocks for vfork |
| 302 | * child completion if @clone_flags has the %CLONE_VFORK bit set. |
| 303 | * The @child pointer may be invalid if a self-reaping child died and |
| 304 | * tracehook_report_clone() took no action to prevent it from self-reaping. |
| 305 | * |
| 306 | * Called with no locks held. |
| 307 | */ |
| 308 | static inline void tracehook_report_clone_complete(int trace, |
| 309 | struct pt_regs *regs, |
| 310 | unsigned long clone_flags, |
| 311 | pid_t pid, |
| 312 | struct task_struct *child) |
| 313 | { |
| 314 | if (unlikely(trace)) |
| 315 | ptrace_event(0, trace, pid); |
| 316 | } |
| 317 | |
Roland McGrath | daded34 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 318 | /** |
| 319 | * tracehook_report_vfork_done - vfork parent's child has exited or exec'd |
| 320 | * @child: child task, already running |
| 321 | * @pid: new child's PID in the parent's namespace |
| 322 | * |
| 323 | * Called after a %CLONE_VFORK parent has waited for the child to complete. |
| 324 | * The clone/vfork system call will return immediately after this. |
| 325 | * The @child pointer may be invalid if a self-reaping child died and |
| 326 | * tracehook_report_clone() took no action to prevent it from self-reaping. |
| 327 | * |
| 328 | * Called with no locks held. |
| 329 | */ |
| 330 | static inline void tracehook_report_vfork_done(struct task_struct *child, |
| 331 | pid_t pid) |
| 332 | { |
| 333 | ptrace_event(PT_TRACE_VFORK_DONE, PTRACE_EVENT_VFORK_DONE, pid); |
| 334 | } |
| 335 | |
Roland McGrath | dae3357 | 2008-07-25 19:45:48 -0700 | [diff] [blame] | 336 | /** |
| 337 | * tracehook_prepare_release_task - task is being reaped, clean up tracing |
| 338 | * @task: task in %EXIT_DEAD state |
| 339 | * |
| 340 | * This is called in release_task() just before @task gets finally reaped |
| 341 | * and freed. This would be the ideal place to remove and clean up any |
| 342 | * tracing-related state for @task. |
| 343 | * |
| 344 | * Called with no locks held. |
| 345 | */ |
| 346 | static inline void tracehook_prepare_release_task(struct task_struct *task) |
| 347 | { |
| 348 | } |
| 349 | |
| 350 | /** |
Roland McGrath | a9906a1 | 2008-07-26 14:41:26 -0700 | [diff] [blame] | 351 | * tracehook_finish_release_task - final tracing clean-up |
Roland McGrath | dae3357 | 2008-07-25 19:45:48 -0700 | [diff] [blame] | 352 | * @task: task in %EXIT_DEAD state |
| 353 | * |
| 354 | * This is called in release_task() when @task is being in the middle of |
| 355 | * being reaped. After this, there must be no tracing entanglements. |
| 356 | * |
| 357 | * Called with write_lock_irq(&tasklist_lock) held. |
| 358 | */ |
| 359 | static inline void tracehook_finish_release_task(struct task_struct *task) |
| 360 | { |
| 361 | ptrace_release_task(task); |
| 362 | } |
| 363 | |
Roland McGrath | c45aea2 | 2008-07-25 19:45:50 -0700 | [diff] [blame] | 364 | /** |
| 365 | * tracehook_signal_handler - signal handler setup is complete |
| 366 | * @sig: number of signal being delivered |
| 367 | * @info: siginfo_t of signal being delivered |
| 368 | * @ka: sigaction setting that chose the handler |
| 369 | * @regs: user register state |
| 370 | * @stepping: nonzero if debugger single-step or block-step in use |
| 371 | * |
| 372 | * Called by the arch code after a signal handler has been set up. |
| 373 | * Register and stack state reflects the user handler about to run. |
| 374 | * Signal mask changes have already been made. |
| 375 | * |
| 376 | * Called without locks, shortly before returning to user mode |
| 377 | * (or handling more signals). |
| 378 | */ |
| 379 | static inline void tracehook_signal_handler(int sig, siginfo_t *info, |
| 380 | const struct k_sigaction *ka, |
| 381 | struct pt_regs *regs, int stepping) |
| 382 | { |
| 383 | if (stepping) |
| 384 | ptrace_notify(SIGTRAP); |
| 385 | } |
| 386 | |
Roland McGrath | 35de254 | 2008-07-25 19:45:51 -0700 | [diff] [blame] | 387 | /** |
| 388 | * tracehook_consider_ignored_signal - suppress short-circuit of ignored signal |
| 389 | * @task: task receiving the signal |
| 390 | * @sig: signal number being sent |
| 391 | * @handler: %SIG_IGN or %SIG_DFL |
| 392 | * |
| 393 | * Return zero iff tracing doesn't care to examine this ignored signal, |
| 394 | * so it can short-circuit normal delivery and never even get queued. |
| 395 | * Either @handler is %SIG_DFL and @sig's default is ignore, or it's %SIG_IGN. |
| 396 | * |
| 397 | * Called with @task->sighand->siglock held. |
| 398 | */ |
| 399 | static inline int tracehook_consider_ignored_signal(struct task_struct *task, |
| 400 | int sig, |
| 401 | void __user *handler) |
| 402 | { |
| 403 | return (task_ptrace(task) & PT_PTRACED) != 0; |
| 404 | } |
| 405 | |
Roland McGrath | 445a91d | 2008-07-25 19:45:52 -0700 | [diff] [blame] | 406 | /** |
| 407 | * tracehook_consider_fatal_signal - suppress special handling of fatal signal |
| 408 | * @task: task receiving the signal |
| 409 | * @sig: signal number being sent |
| 410 | * @handler: %SIG_DFL or %SIG_IGN |
| 411 | * |
| 412 | * Return nonzero to prevent special handling of this termination signal. |
| 413 | * Normally @handler is %SIG_DFL. It can be %SIG_IGN if @sig is ignored, |
| 414 | * in which case force_sig() is about to reset it to %SIG_DFL. |
| 415 | * When this returns zero, this signal might cause a quick termination |
| 416 | * that does not give the debugger a chance to intercept the signal. |
| 417 | * |
| 418 | * Called with or without @task->sighand->siglock held. |
| 419 | */ |
| 420 | static inline int tracehook_consider_fatal_signal(struct task_struct *task, |
| 421 | int sig, |
| 422 | void __user *handler) |
| 423 | { |
| 424 | return (task_ptrace(task) & PT_PTRACED) != 0; |
| 425 | } |
| 426 | |
Roland McGrath | 7bcf6a2 | 2008-07-25 19:45:53 -0700 | [diff] [blame] | 427 | /** |
Roland McGrath | b787f7b | 2008-07-25 19:45:55 -0700 | [diff] [blame] | 428 | * tracehook_force_sigpending - let tracing force signal_pending(current) on |
| 429 | * |
| 430 | * Called when recomputing our signal_pending() flag. Return nonzero |
| 431 | * to force the signal_pending() flag on, so that tracehook_get_signal() |
| 432 | * will be called before the next return to user mode. |
| 433 | * |
| 434 | * Called with @current->sighand->siglock held. |
| 435 | */ |
| 436 | static inline int tracehook_force_sigpending(void) |
| 437 | { |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | /** |
Roland McGrath | 7bcf6a2 | 2008-07-25 19:45:53 -0700 | [diff] [blame] | 442 | * tracehook_get_signal - deliver synthetic signal to traced task |
| 443 | * @task: @current |
| 444 | * @regs: task_pt_regs(@current) |
| 445 | * @info: details of synthetic signal |
| 446 | * @return_ka: sigaction for synthetic signal |
| 447 | * |
| 448 | * Return zero to check for a real pending signal normally. |
| 449 | * Return -1 after releasing the siglock to repeat the check. |
| 450 | * Return a signal number to induce an artifical signal delivery, |
| 451 | * setting *@info and *@return_ka to specify its details and behavior. |
| 452 | * |
| 453 | * The @return_ka->sa_handler value controls the disposition of the |
| 454 | * signal, no matter the signal number. For %SIG_DFL, the return value |
| 455 | * is a representative signal to indicate the behavior (e.g. %SIGTERM |
| 456 | * for death, %SIGQUIT for core dump, %SIGSTOP for job control stop, |
| 457 | * %SIGTSTP for stop unless in an orphaned pgrp), but the signal number |
| 458 | * reported will be @info->si_signo instead. |
| 459 | * |
| 460 | * Called with @task->sighand->siglock held, before dequeuing pending signals. |
| 461 | */ |
| 462 | static inline int tracehook_get_signal(struct task_struct *task, |
| 463 | struct pt_regs *regs, |
| 464 | siginfo_t *info, |
| 465 | struct k_sigaction *return_ka) |
| 466 | { |
| 467 | return 0; |
| 468 | } |
| 469 | |
Roland McGrath | fa00b80 | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 470 | /** |
| 471 | * tracehook_notify_jctl - report about job control stop/continue |
| 472 | * @notify: nonzero if this is the last thread in the group to stop |
| 473 | * @why: %CLD_STOPPED or %CLD_CONTINUED |
| 474 | * |
| 475 | * This is called when we might call do_notify_parent_cldstop(). |
| 476 | * It's called when about to stop for job control; we are already in |
| 477 | * %TASK_STOPPED state, about to call schedule(). It's also called when |
| 478 | * a delayed %CLD_STOPPED or %CLD_CONTINUED report is ready to be made. |
| 479 | * |
| 480 | * Return nonzero to generate a %SIGCHLD with @why, which is |
| 481 | * normal if @notify is nonzero. |
| 482 | * |
| 483 | * Called with no locks held. |
| 484 | */ |
| 485 | static inline int tracehook_notify_jctl(int notify, int why) |
| 486 | { |
| 487 | return notify || (current->ptrace & PT_PTRACED); |
| 488 | } |
| 489 | |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 490 | /** |
| 491 | * tracehook_notify_death - task is dead, ready to notify parent |
| 492 | * @task: @current task now exiting |
| 493 | * @death_cookie: value to pass to tracehook_report_death() |
| 494 | * @group_dead: nonzero if this was the last thread in the group to die |
| 495 | * |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 496 | * A return value >= 0 means call do_notify_parent() with that signal |
| 497 | * number. Negative return value can be %DEATH_REAP to self-reap right |
| 498 | * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our |
| 499 | * parent. Note that a return value of 0 means a do_notify_parent() call |
| 500 | * that sends no signal, but still wakes up a parent blocked in wait*(). |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 501 | * |
| 502 | * Called with write_lock_irq(&tasklist_lock) held. |
| 503 | */ |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 504 | #define DEATH_REAP -1 |
| 505 | #define DEATH_DELAYED_GROUP_LEADER -2 |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 506 | static inline int tracehook_notify_death(struct task_struct *task, |
| 507 | void **death_cookie, int group_dead) |
| 508 | { |
| 509 | if (task->exit_signal == -1) |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 510 | return task->ptrace ? SIGCHLD : DEATH_REAP; |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 511 | |
| 512 | /* |
| 513 | * If something other than our normal parent is ptracing us, then |
| 514 | * send it a SIGCHLD instead of honoring exit_signal. exit_signal |
| 515 | * only has special meaning to our real parent. |
| 516 | */ |
| 517 | if (thread_group_empty(task) && !ptrace_reparented(task)) |
| 518 | return task->exit_signal; |
| 519 | |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 520 | return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 521 | } |
| 522 | |
| 523 | /** |
| 524 | * tracehook_report_death - task is dead and ready to be reaped |
| 525 | * @task: @current task now exiting |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 526 | * @signal: return value from tracheook_notify_death() |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 527 | * @death_cookie: value passed back from tracehook_notify_death() |
| 528 | * @group_dead: nonzero if this was the last thread in the group to die |
| 529 | * |
| 530 | * Thread has just become a zombie or is about to self-reap. If positive, |
| 531 | * @signal is the signal number just sent to the parent (usually %SIGCHLD). |
Roland McGrath | 5c7edcd | 2008-07-31 02:04:09 -0700 | [diff] [blame^] | 532 | * If @signal is %DEATH_REAP, this thread will self-reap. If @signal is |
| 533 | * %DEATH_DELAYED_GROUP_LEADER, this is a delayed_group_leader() zombie. |
| 534 | * The @death_cookie was passed back by tracehook_notify_death(). |
Roland McGrath | 2b2a1ff | 2008-07-25 19:45:54 -0700 | [diff] [blame] | 535 | * |
| 536 | * If normal reaping is not inhibited, @task->exit_state might be changing |
| 537 | * in parallel. |
| 538 | * |
| 539 | * Called without locks. |
| 540 | */ |
| 541 | static inline void tracehook_report_death(struct task_struct *task, |
| 542 | int signal, void *death_cookie, |
| 543 | int group_dead) |
| 544 | { |
| 545 | } |
| 546 | |
Roland McGrath | 64b1208d | 2008-07-25 19:45:56 -0700 | [diff] [blame] | 547 | #ifdef TIF_NOTIFY_RESUME |
| 548 | /** |
| 549 | * set_notify_resume - cause tracehook_notify_resume() to be called |
| 550 | * @task: task that will call tracehook_notify_resume() |
| 551 | * |
| 552 | * Calling this arranges that @task will call tracehook_notify_resume() |
| 553 | * before returning to user mode. If it's already running in user mode, |
| 554 | * it will enter the kernel and call tracehook_notify_resume() soon. |
| 555 | * If it's blocked, it will not be woken. |
| 556 | */ |
| 557 | static inline void set_notify_resume(struct task_struct *task) |
| 558 | { |
| 559 | if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME)) |
| 560 | kick_process(task); |
| 561 | } |
| 562 | |
| 563 | /** |
| 564 | * tracehook_notify_resume - report when about to return to user mode |
| 565 | * @regs: user-mode registers of @current task |
| 566 | * |
| 567 | * This is called when %TIF_NOTIFY_RESUME has been set. Now we are |
| 568 | * about to return to user mode, and the user state in @regs can be |
| 569 | * inspected or adjusted. The caller in arch code has cleared |
| 570 | * %TIF_NOTIFY_RESUME before the call. If the flag gets set again |
| 571 | * asynchronously, this will be called again before we return to |
| 572 | * user mode. |
| 573 | * |
| 574 | * Called without locks. |
| 575 | */ |
| 576 | static inline void tracehook_notify_resume(struct pt_regs *regs) |
| 577 | { |
| 578 | } |
| 579 | #endif /* TIF_NOTIFY_RESUME */ |
| 580 | |
Roland McGrath | 88ac292 | 2008-07-25 19:45:43 -0700 | [diff] [blame] | 581 | #endif /* <linux/tracehook.h> */ |