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