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 child->jobctl = 0; 146 child->ptrace = 0; 147 child->parent = child->real_parent; 148 149 if (unlikely(ptrace) && current->ptrace) { 150 child->ptrace = current->ptrace; 151 __ptrace_link(child, current->parent); 152 153 if (child->ptrace & PT_SEIZED) 154 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP); 155 else 156 sigaddset(&child->pending.signal, SIGSTOP); 157 158 set_tsk_thread_flag(child, TIF_SIGPENDING); 159 } 160 } 161 162 /** 163 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped 164 * @task: task in %EXIT_DEAD state 165 * 166 * Called with write_lock(&tasklist_lock) held. 167 */ 168 static inline void ptrace_release_task(struct task_struct *task) 169 { 170 BUG_ON(!list_empty(&task->ptraced)); 171 ptrace_unlink(task); 172 BUG_ON(!list_empty(&task->ptrace_entry)); 173 } 174 175 #ifndef force_successful_syscall_return 176 /* 177 * System call handlers that, upon successful completion, need to return a 178 * negative value should call force_successful_syscall_return() right before 179 * returning. On architectures where the syscall convention provides for a 180 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly 181 * others), this macro can be used to ensure that the error flag will not get 182 * set. On architectures which do not support a separate error flag, the macro 183 * is a no-op and the spurious error condition needs to be filtered out by some 184 * other means (e.g., in user-level, by passing an extra argument to the 185 * syscall handler, or something along those lines). 186 */ 187 #define force_successful_syscall_return() do { } while (0) 188 #endif 189 190 #ifndef is_syscall_success 191 /* 192 * On most systems we can tell if a syscall is a success based on if the retval 193 * is an error value. On some systems like ia64 and powerpc they have different 194 * indicators of success/failure and must define their own. 195 */ 196 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs)))) 197 #endif 198 199 /* 200 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__. 201 * 202 * These do-nothing inlines are used when the arch does not 203 * implement single-step. The kerneldoc comments are here 204 * to document the interface for all arch definitions. 205 */ 206 207 #ifndef arch_has_single_step 208 /** 209 * arch_has_single_step - does this CPU support user-mode single-step? 210 * 211 * If this is defined, then there must be function declarations or 212 * inlines for user_enable_single_step() and user_disable_single_step(). 213 * arch_has_single_step() should evaluate to nonzero iff the machine 214 * supports instruction single-step for user mode. 215 * It can be a constant or it can test a CPU feature bit. 216 */ 217 #define arch_has_single_step() (0) 218 219 /** 220 * user_enable_single_step - single-step in user-mode task 221 * @task: either current or a task stopped in %TASK_TRACED 222 * 223 * This can only be called when arch_has_single_step() has returned nonzero. 224 * Set @task so that when it returns to user mode, it will trap after the 225 * next single instruction executes. If arch_has_block_step() is defined, 226 * this must clear the effects of user_enable_block_step() too. 227 */ 228 static inline void user_enable_single_step(struct task_struct *task) 229 { 230 BUG(); /* This can never be called. */ 231 } 232 233 /** 234 * user_disable_single_step - cancel user-mode single-step 235 * @task: either current or a task stopped in %TASK_TRACED 236 * 237 * Clear @task of the effects of user_enable_single_step() and 238 * user_enable_block_step(). This can be called whether or not either 239 * of those was ever called on @task, and even if arch_has_single_step() 240 * returned zero. 241 */ 242 static inline void user_disable_single_step(struct task_struct *task) 243 { 244 } 245 #else 246 extern void user_enable_single_step(struct task_struct *); 247 extern void user_disable_single_step(struct task_struct *); 248 #endif /* arch_has_single_step */ 249 250 #ifndef arch_has_block_step 251 /** 252 * arch_has_block_step - does this CPU support user-mode block-step? 253 * 254 * If this is defined, then there must be a function declaration or inline 255 * for user_enable_block_step(), and arch_has_single_step() must be defined 256 * too. arch_has_block_step() should evaluate to nonzero iff the machine 257 * supports step-until-branch for user mode. It can be a constant or it 258 * can test a CPU feature bit. 259 */ 260 #define arch_has_block_step() (0) 261 262 /** 263 * user_enable_block_step - step until branch in user-mode task 264 * @task: either current or a task stopped in %TASK_TRACED 265 * 266 * This can only be called when arch_has_block_step() has returned nonzero, 267 * and will never be called when single-instruction stepping is being used. 268 * Set @task so that when it returns to user mode, it will trap after the 269 * next branch or trap taken. 270 */ 271 static inline void user_enable_block_step(struct task_struct *task) 272 { 273 BUG(); /* This can never be called. */ 274 } 275 #else 276 extern void user_enable_block_step(struct task_struct *); 277 #endif /* arch_has_block_step */ 278 279 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO 280 extern void user_single_step_siginfo(struct task_struct *tsk, 281 struct pt_regs *regs, siginfo_t *info); 282 #else 283 static inline void user_single_step_siginfo(struct task_struct *tsk, 284 struct pt_regs *regs, siginfo_t *info) 285 { 286 memset(info, 0, sizeof(*info)); 287 info->si_signo = SIGTRAP; 288 } 289 #endif 290 291 #ifndef arch_ptrace_stop_needed 292 /** 293 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called 294 * @code: current->exit_code value ptrace will stop with 295 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 296 * 297 * This is called with the siglock held, to decide whether or not it's 298 * necessary to release the siglock and call arch_ptrace_stop() with the 299 * same @code and @info arguments. It can be defined to a constant if 300 * arch_ptrace_stop() is never required, or always is. On machines where 301 * this makes sense, it should be defined to a quick test to optimize out 302 * calling arch_ptrace_stop() when it would be superfluous. For example, 303 * if the thread has not been back to user mode since the last stop, the 304 * thread state might indicate that nothing needs to be done. 305 */ 306 #define arch_ptrace_stop_needed(code, info) (0) 307 #endif 308 309 #ifndef arch_ptrace_stop 310 /** 311 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace 312 * @code: current->exit_code value ptrace will stop with 313 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 314 * 315 * This is called with no locks held when arch_ptrace_stop_needed() has 316 * just returned nonzero. It is allowed to block, e.g. for user memory 317 * access. The arch can have machine-specific work to be done before 318 * ptrace stops. On ia64, register backing store gets written back to user 319 * memory here. Since this can be costly (requires dropping the siglock), 320 * we only do it when the arch requires it for this particular stop, as 321 * indicated by arch_ptrace_stop_needed(). 322 */ 323 #define arch_ptrace_stop(code, info) do { } while (0) 324 #endif 325 326 #ifndef current_pt_regs 327 #define current_pt_regs() task_pt_regs(current) 328 #endif 329 330 #ifndef ptrace_signal_deliver 331 #define ptrace_signal_deliver() ((void)0) 332 #endif 333 334 /* 335 * unlike current_pt_regs(), this one is equal to task_pt_regs(current) 336 * on *all* architectures; the only reason to have a per-arch definition 337 * is optimisation. 338 */ 339 #ifndef signal_pt_regs 340 #define signal_pt_regs() task_pt_regs(current) 341 #endif 342 343 #ifndef current_user_stack_pointer 344 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs()) 345 #endif 346 347 extern int task_current_syscall(struct task_struct *target, long *callno, 348 unsigned long args[6], unsigned int maxargs, 349 unsigned long *sp, unsigned long *pc); 350 351 #endif 352