1 #ifndef _LINUX_PTRACE_H 2 #define _LINUX_PTRACE_H 3 4 #include <linux/compiler.h> /* For unlikely. */ 5 #include <linux/sched.h> /* For struct task_struct. */ 6 #include <linux/err.h> /* for IS_ERR_VALUE */ 7 #include <linux/bug.h> /* For BUG_ON. */ 8 #include <uapi/linux/ptrace.h> 9 10 /* 11 * Ptrace flags 12 * 13 * The owner ship rules for task->ptrace which holds the ptrace 14 * flags is simple. When a task is running it owns it's task->ptrace 15 * flags. When the a task is stopped the ptracer owns task->ptrace. 16 */ 17 18 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */ 19 #define PT_PTRACED 0x00000001 20 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ 21 #define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */ 22 23 #define PT_OPT_FLAG_SHIFT 3 24 /* PT_TRACE_* event enable flags */ 25 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event))) 26 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0) 27 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) 28 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) 29 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) 30 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC) 31 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) 32 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) 33 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) 34 35 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT) 36 37 /* single stepping state bits (used on ARM and PA-RISC) */ 38 #define PT_SINGLESTEP_BIT 31 39 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) 40 #define PT_BLOCKSTEP_BIT 30 41 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT) 42 43 extern long arch_ptrace(struct task_struct *child, long request, 44 unsigned long addr, unsigned long data); 45 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len); 46 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len); 47 extern void ptrace_disable(struct task_struct *); 48 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state); 49 extern int ptrace_request(struct task_struct *child, long request, 50 unsigned long addr, unsigned long data); 51 extern void ptrace_notify(int exit_code); 52 extern void __ptrace_link(struct task_struct *child, 53 struct task_struct *new_parent); 54 extern void __ptrace_unlink(struct task_struct *child); 55 extern void exit_ptrace(struct task_struct *tracer); 56 #define PTRACE_MODE_READ 0x01 57 #define PTRACE_MODE_ATTACH 0x02 58 #define PTRACE_MODE_NOAUDIT 0x04 59 /* Returns true on success, false on denial. */ 60 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode); 61 62 static inline int ptrace_reparented(struct task_struct *child) 63 { 64 return !same_thread_group(child->real_parent, child->parent); 65 } 66 67 static inline void ptrace_unlink(struct task_struct *child) 68 { 69 if (unlikely(child->ptrace)) 70 __ptrace_unlink(child); 71 } 72 73 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 74 unsigned long data); 75 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 76 unsigned long data); 77 78 /** 79 * ptrace_parent - return the task that is tracing the given task 80 * @task: task to consider 81 * 82 * Returns %NULL if no one is tracing @task, or the &struct task_struct 83 * pointer to its tracer. 84 * 85 * Must called under rcu_read_lock(). The pointer returned might be kept 86 * live only by RCU. During exec, this may be called with task_lock() held 87 * on @task, still held from when check_unsafe_exec() was called. 88 */ 89 static inline struct task_struct *ptrace_parent(struct task_struct *task) 90 { 91 if (unlikely(task->ptrace)) 92 return rcu_dereference(task->parent); 93 return NULL; 94 } 95 96 /** 97 * ptrace_event_enabled - test whether a ptrace event is enabled 98 * @task: ptracee of interest 99 * @event: %PTRACE_EVENT_* to test 100 * 101 * Test whether @event is enabled for ptracee @task. 102 * 103 * Returns %true if @event is enabled, %false otherwise. 104 */ 105 static inline bool ptrace_event_enabled(struct task_struct *task, int event) 106 { 107 return task->ptrace & PT_EVENT_FLAG(event); 108 } 109 110 /** 111 * ptrace_event - possibly stop for a ptrace event notification 112 * @event: %PTRACE_EVENT_* value to report 113 * @message: value for %PTRACE_GETEVENTMSG to return 114 * 115 * Check whether @event is enabled and, if so, report @event and @message 116 * to the ptrace parent. 117 * 118 * Called without locks. 119 */ 120 static inline void ptrace_event(int event, unsigned long message) 121 { 122 if (unlikely(ptrace_event_enabled(current, event))) { 123 current->ptrace_message = message; 124 ptrace_notify((event << 8) | SIGTRAP); 125 } else if (event == PTRACE_EVENT_EXEC) { 126 /* legacy EXEC report via SIGTRAP */ 127 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED) 128 send_sig(SIGTRAP, current, 0); 129 } 130 } 131 132 /** 133 * ptrace_init_task - initialize ptrace state for a new child 134 * @child: new child task 135 * @ptrace: true if child should be ptrace'd by parent's tracer 136 * 137 * This is called immediately after adding @child to its parent's children 138 * list. @ptrace is false in the normal case, and true to ptrace @child. 139 * 140 * Called with current's siglock and write_lock_irq(&tasklist_lock) held. 141 */ 142 static inline void ptrace_init_task(struct task_struct *child, bool ptrace) 143 { 144 INIT_LIST_HEAD(&child->ptrace_entry); 145 INIT_LIST_HEAD(&child->ptraced); 146 #ifdef CONFIG_HAVE_HW_BREAKPOINT 147 atomic_set(&child->ptrace_bp_refcnt, 1); 148 #endif 149 child->jobctl = 0; 150 child->ptrace = 0; 151 child->parent = child->real_parent; 152 153 if (unlikely(ptrace) && current->ptrace) { 154 child->ptrace = current->ptrace; 155 __ptrace_link(child, current->parent); 156 157 if (child->ptrace & PT_SEIZED) 158 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP); 159 else 160 sigaddset(&child->pending.signal, SIGSTOP); 161 162 set_tsk_thread_flag(child, TIF_SIGPENDING); 163 } 164 } 165 166 /** 167 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped 168 * @task: task in %EXIT_DEAD state 169 * 170 * Called with write_lock(&tasklist_lock) held. 171 */ 172 static inline void ptrace_release_task(struct task_struct *task) 173 { 174 BUG_ON(!list_empty(&task->ptraced)); 175 ptrace_unlink(task); 176 BUG_ON(!list_empty(&task->ptrace_entry)); 177 } 178 179 #ifndef force_successful_syscall_return 180 /* 181 * System call handlers that, upon successful completion, need to return a 182 * negative value should call force_successful_syscall_return() right before 183 * returning. On architectures where the syscall convention provides for a 184 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly 185 * others), this macro can be used to ensure that the error flag will not get 186 * set. On architectures which do not support a separate error flag, the macro 187 * is a no-op and the spurious error condition needs to be filtered out by some 188 * other means (e.g., in user-level, by passing an extra argument to the 189 * syscall handler, or something along those lines). 190 */ 191 #define force_successful_syscall_return() do { } while (0) 192 #endif 193 194 #ifndef is_syscall_success 195 /* 196 * On most systems we can tell if a syscall is a success based on if the retval 197 * is an error value. On some systems like ia64 and powerpc they have different 198 * indicators of success/failure and must define their own. 199 */ 200 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs)))) 201 #endif 202 203 /* 204 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__. 205 * 206 * These do-nothing inlines are used when the arch does not 207 * implement single-step. The kerneldoc comments are here 208 * to document the interface for all arch definitions. 209 */ 210 211 #ifndef arch_has_single_step 212 /** 213 * arch_has_single_step - does this CPU support user-mode single-step? 214 * 215 * If this is defined, then there must be function declarations or 216 * inlines for user_enable_single_step() and user_disable_single_step(). 217 * arch_has_single_step() should evaluate to nonzero iff the machine 218 * supports instruction single-step for user mode. 219 * It can be a constant or it can test a CPU feature bit. 220 */ 221 #define arch_has_single_step() (0) 222 223 /** 224 * user_enable_single_step - single-step in user-mode task 225 * @task: either current or a task stopped in %TASK_TRACED 226 * 227 * This can only be called when arch_has_single_step() has returned nonzero. 228 * Set @task so that when it returns to user mode, it will trap after the 229 * next single instruction executes. If arch_has_block_step() is defined, 230 * this must clear the effects of user_enable_block_step() too. 231 */ 232 static inline void user_enable_single_step(struct task_struct *task) 233 { 234 BUG(); /* This can never be called. */ 235 } 236 237 /** 238 * user_disable_single_step - cancel user-mode single-step 239 * @task: either current or a task stopped in %TASK_TRACED 240 * 241 * Clear @task of the effects of user_enable_single_step() and 242 * user_enable_block_step(). This can be called whether or not either 243 * of those was ever called on @task, and even if arch_has_single_step() 244 * returned zero. 245 */ 246 static inline void user_disable_single_step(struct task_struct *task) 247 { 248 } 249 #else 250 extern void user_enable_single_step(struct task_struct *); 251 extern void user_disable_single_step(struct task_struct *); 252 #endif /* arch_has_single_step */ 253 254 #ifndef arch_has_block_step 255 /** 256 * arch_has_block_step - does this CPU support user-mode block-step? 257 * 258 * If this is defined, then there must be a function declaration or inline 259 * for user_enable_block_step(), and arch_has_single_step() must be defined 260 * too. arch_has_block_step() should evaluate to nonzero iff the machine 261 * supports step-until-branch for user mode. It can be a constant or it 262 * can test a CPU feature bit. 263 */ 264 #define arch_has_block_step() (0) 265 266 /** 267 * user_enable_block_step - step until branch in user-mode task 268 * @task: either current or a task stopped in %TASK_TRACED 269 * 270 * This can only be called when arch_has_block_step() has returned nonzero, 271 * and will never be called when single-instruction stepping is being used. 272 * Set @task so that when it returns to user mode, it will trap after the 273 * next branch or trap taken. 274 */ 275 static inline void user_enable_block_step(struct task_struct *task) 276 { 277 BUG(); /* This can never be called. */ 278 } 279 #else 280 extern void user_enable_block_step(struct task_struct *); 281 #endif /* arch_has_block_step */ 282 283 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO 284 extern void user_single_step_siginfo(struct task_struct *tsk, 285 struct pt_regs *regs, siginfo_t *info); 286 #else 287 static inline void user_single_step_siginfo(struct task_struct *tsk, 288 struct pt_regs *regs, siginfo_t *info) 289 { 290 memset(info, 0, sizeof(*info)); 291 info->si_signo = SIGTRAP; 292 } 293 #endif 294 295 #ifndef arch_ptrace_stop_needed 296 /** 297 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called 298 * @code: current->exit_code value ptrace will stop with 299 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 300 * 301 * This is called with the siglock held, to decide whether or not it's 302 * necessary to release the siglock and call arch_ptrace_stop() with the 303 * same @code and @info arguments. It can be defined to a constant if 304 * arch_ptrace_stop() is never required, or always is. On machines where 305 * this makes sense, it should be defined to a quick test to optimize out 306 * calling arch_ptrace_stop() when it would be superfluous. For example, 307 * if the thread has not been back to user mode since the last stop, the 308 * thread state might indicate that nothing needs to be done. 309 */ 310 #define arch_ptrace_stop_needed(code, info) (0) 311 #endif 312 313 #ifndef arch_ptrace_stop 314 /** 315 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace 316 * @code: current->exit_code value ptrace will stop with 317 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 318 * 319 * This is called with no locks held when arch_ptrace_stop_needed() has 320 * just returned nonzero. It is allowed to block, e.g. for user memory 321 * access. The arch can have machine-specific work to be done before 322 * ptrace stops. On ia64, register backing store gets written back to user 323 * memory here. Since this can be costly (requires dropping the siglock), 324 * we only do it when the arch requires it for this particular stop, as 325 * indicated by arch_ptrace_stop_needed(). 326 */ 327 #define arch_ptrace_stop(code, info) do { } while (0) 328 #endif 329 330 #ifndef current_pt_regs 331 #define current_pt_regs() task_pt_regs(current) 332 #endif 333 334 #ifndef ptrace_signal_deliver 335 #define ptrace_signal_deliver() ((void)0) 336 #endif 337 338 /* 339 * unlike current_pt_regs(), this one is equal to task_pt_regs(current) 340 * on *all* architectures; the only reason to have a per-arch definition 341 * is optimisation. 342 */ 343 #ifndef signal_pt_regs 344 #define signal_pt_regs() task_pt_regs(current) 345 #endif 346 347 #ifndef current_user_stack_pointer 348 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs()) 349 #endif 350 351 extern int task_current_syscall(struct task_struct *target, long *callno, 352 unsigned long args[6], unsigned int maxargs, 353 unsigned long *sp, unsigned long *pc); 354 355 #ifdef CONFIG_HAVE_HW_BREAKPOINT 356 extern int ptrace_get_breakpoints(struct task_struct *tsk); 357 extern void ptrace_put_breakpoints(struct task_struct *tsk); 358 #else 359 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { } 360 #endif /* CONFIG_HAVE_HW_BREAKPOINT */ 361 362 #endif 363