Linux-2.6.12-rc2
[linux-3.10.git] / arch / um / kernel / ptrace.c
1 /* 
2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include "linux/sched.h"
7 #include "linux/mm.h"
8 #include "linux/errno.h"
9 #include "linux/smp_lock.h"
10 #include "linux/security.h"
11 #include "linux/ptrace.h"
12 #include "linux/audit.h"
13 #ifdef CONFIG_PROC_MM
14 #include "linux/proc_mm.h"
15 #endif
16 #include "asm/ptrace.h"
17 #include "asm/uaccess.h"
18 #include "kern_util.h"
19 #include "skas_ptrace.h"
20 #include "sysdep/ptrace.h"
21
22 /*
23  * Called by kernel/ptrace.c when detaching..
24  */
25 void ptrace_disable(struct task_struct *child)
26
27         child->ptrace &= ~PT_DTRACE;
28         child->thread.singlestep_syscall = 0;
29 }
30
31 long sys_ptrace(long request, long pid, long addr, long data)
32 {
33         struct task_struct *child;
34         int i, ret;
35
36         lock_kernel();
37         ret = -EPERM;
38         if (request == PTRACE_TRACEME) {
39                 /* are we already being traced? */
40                 if (current->ptrace & PT_PTRACED)
41                         goto out;
42
43                 ret = security_ptrace(current->parent, current);
44                 if (ret)
45                         goto out;
46
47                 /* set the ptrace bit in the process flags. */
48                 current->ptrace |= PT_PTRACED;
49                 ret = 0;
50                 goto out;
51         }
52         ret = -ESRCH;
53         read_lock(&tasklist_lock);
54         child = find_task_by_pid(pid);
55         if (child)
56                 get_task_struct(child);
57         read_unlock(&tasklist_lock);
58         if (!child)
59                 goto out;
60
61         ret = -EPERM;
62         if (pid == 1)           /* you may not mess with init */
63                 goto out_tsk;
64
65         if (request == PTRACE_ATTACH) {
66                 ret = ptrace_attach(child);
67                 goto out_tsk;
68         }
69
70         ret = ptrace_check_attach(child, request == PTRACE_KILL);
71         if (ret < 0)
72                 goto out_tsk;
73
74         switch (request) {
75                 /* when I and D space are separate, these will need to be fixed. */
76         case PTRACE_PEEKTEXT: /* read word at location addr. */ 
77         case PTRACE_PEEKDATA: {
78                 unsigned long tmp;
79                 int copied;
80
81                 ret = -EIO;
82                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
83                 if (copied != sizeof(tmp))
84                         break;
85                 ret = put_user(tmp, (unsigned long __user *) data);
86                 break;
87         }
88
89         /* read the word at location addr in the USER area. */
90         case PTRACE_PEEKUSR: {
91                 unsigned long tmp;
92
93                 ret = -EIO;
94                 if ((addr & 3) || addr < 0) 
95                         break;
96
97                 tmp = 0;  /* Default return condition */
98                 if(addr < MAX_REG_OFFSET){
99                         tmp = getreg(child, addr);
100                 }
101                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
102                         (addr <= offsetof(struct user, u_debugreg[7]))){
103                         addr -= offsetof(struct user, u_debugreg[0]);
104                         addr = addr >> 2;
105                         tmp = child->thread.arch.debugregs[addr];
106                 }
107                 ret = put_user(tmp, (unsigned long __user *) data);
108                 break;
109         }
110
111         /* when I and D space are separate, this will have to be fixed. */
112         case PTRACE_POKETEXT: /* write the word at location addr. */
113         case PTRACE_POKEDATA:
114                 ret = -EIO;
115                 if (access_process_vm(child, addr, &data, sizeof(data), 
116                                       1) != sizeof(data))
117                         break;
118                 ret = 0;
119                 break;
120
121         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
122                 ret = -EIO;
123                 if ((addr & 3) || addr < 0)
124                         break;
125
126                 if (addr < MAX_REG_OFFSET) {
127                         ret = putreg(child, addr, data);
128                         break;
129                 }
130 #if 0 /* XXX x86_64 */
131                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
132                         (addr <= offsetof(struct user, u_debugreg[7]))){
133                           addr -= offsetof(struct user, u_debugreg[0]);
134                           addr = addr >> 2;
135                           if((addr == 4) || (addr == 5)) break;
136                           child->thread.arch.debugregs[addr] = data;
137                           ret = 0;
138                 }
139 #endif
140
141                 break;
142
143         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
144         case PTRACE_CONT: { /* restart after signal. */
145                 ret = -EIO;
146                 if ((unsigned long) data > _NSIG)
147                         break;
148
149                 child->ptrace &= ~PT_DTRACE;
150                 child->thread.singlestep_syscall = 0;
151                 if (request == PTRACE_SYSCALL) {
152                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
153                 }
154                 else {
155                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
156                 }
157                 child->exit_code = data;
158                 wake_up_process(child);
159                 ret = 0;
160                 break;
161         }
162
163 /*
164  * make the child exit.  Best I can do is send it a sigkill. 
165  * perhaps it should be put in the status that it wants to 
166  * exit.
167  */
168         case PTRACE_KILL: {
169                 ret = 0;
170                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
171                         break;
172
173                 child->ptrace &= ~PT_DTRACE;
174                 child->thread.singlestep_syscall = 0;
175                 child->exit_code = SIGKILL;
176                 wake_up_process(child);
177                 break;
178         }
179
180         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
181                 ret = -EIO;
182                 if ((unsigned long) data > _NSIG)
183                         break;
184                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
185                 child->ptrace |= PT_DTRACE;
186                 child->thread.singlestep_syscall = 0;
187                 child->exit_code = data;
188                 /* give it a chance to run. */
189                 wake_up_process(child);
190                 ret = 0;
191                 break;
192         }
193
194         case PTRACE_DETACH:
195                 /* detach a process that was attached. */
196                 ret = ptrace_detach(child, data);
197                 break;
198
199 #ifdef PTRACE_GETREGS
200         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
201                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data, 
202                                MAX_REG_OFFSET)) {
203                         ret = -EIO;
204                         break;
205                 }
206                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
207                         __put_user(getreg(child, i),
208                                    (unsigned long __user *) data);
209                         data += sizeof(long);
210                 }
211                 ret = 0;
212                 break;
213         }
214 #endif
215 #ifdef PTRACE_SETREGS
216         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
217                 unsigned long tmp = 0;
218                 if (!access_ok(VERIFY_READ, (unsigned *)data, 
219                                MAX_REG_OFFSET)) {
220                         ret = -EIO;
221                         break;
222                 }
223                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
224                         __get_user(tmp, (unsigned long __user *) data);
225                         putreg(child, i, tmp);
226                         data += sizeof(long);
227                 }
228                 ret = 0;
229                 break;
230         }
231 #endif
232 #ifdef PTRACE_GETFPREGS
233         case PTRACE_GETFPREGS: /* Get the child FPU state. */
234                 ret = get_fpregs(data, child);
235                 break;
236 #endif
237 #ifdef PTRACE_SETFPREGS
238         case PTRACE_SETFPREGS: /* Set the child FPU state. */
239                 ret = set_fpregs(data, child);
240                 break;
241 #endif
242 #ifdef PTRACE_GETFPXREGS
243         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
244                 ret = get_fpxregs(data, child);
245                 break;
246 #endif
247 #ifdef PTRACE_SETFPXREGS
248         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
249                 ret = set_fpxregs(data, child);
250                 break;
251 #endif
252         case PTRACE_FAULTINFO: {
253                 struct ptrace_faultinfo fault;
254
255                 fault = ((struct ptrace_faultinfo) 
256                         { .is_write     = child->thread.err,
257                           .addr         = child->thread.cr2 });
258                 ret = copy_to_user((unsigned long __user *) data, &fault,
259                                    sizeof(fault));
260                 if(ret)
261                         break;
262                 break;
263         }
264         case PTRACE_SIGPENDING:
265                 ret = copy_to_user((unsigned long __user *) data,
266                                    &child->pending.signal,
267                                    sizeof(child->pending.signal));
268                 break;
269
270         case PTRACE_LDT: {
271                 struct ptrace_ldt ldt;
272
273                 if(copy_from_user(&ldt, (unsigned long __user *) data,
274                                   sizeof(ldt))){
275                         ret = -EIO;
276                         break;
277                 }
278
279                 /* This one is confusing, so just punt and return -EIO for 
280                  * now
281                  */
282                 ret = -EIO;
283                 break;
284         }
285 #ifdef CONFIG_PROC_MM
286         case PTRACE_SWITCH_MM: {
287                 struct mm_struct *old = child->mm;
288                 struct mm_struct *new = proc_mm_get_mm(data);
289
290                 if(IS_ERR(new)){
291                         ret = PTR_ERR(new);
292                         break;
293                 }
294
295                 atomic_inc(&new->mm_users);
296                 child->mm = new;
297                 child->active_mm = new;
298                 mmput(old);
299                 ret = 0;
300                 break;
301         }
302 #endif
303         default:
304                 ret = ptrace_request(child, request, addr, data);
305                 break;
306         }
307  out_tsk:
308         put_task_struct(child);
309  out:
310         unlock_kernel();
311         return ret;
312 }
313
314 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
315                   int error_code)
316 {
317         struct siginfo info;
318
319         memset(&info, 0, sizeof(info));
320         info.si_signo = SIGTRAP;
321         info.si_code = TRAP_BRKPT;
322
323         /* User-mode eip? */
324         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
325
326         /* Send us the fakey SIGTRAP */
327         force_sig_info(SIGTRAP, &info, tsk);
328 }
329
330 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
331  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
332  */
333 void syscall_trace(union uml_pt_regs *regs, int entryexit)
334 {
335         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
336         int tracesysgood;
337
338         if (unlikely(current->audit_context)) {
339                 if (!entryexit)
340                         audit_syscall_entry(current, 
341                                             UPT_SYSCALL_NR(&regs->regs),
342                                             UPT_SYSCALL_ARG1(&regs->regs),
343                                             UPT_SYSCALL_ARG2(&regs->regs),
344                                             UPT_SYSCALL_ARG3(&regs->regs),
345                                             UPT_SYSCALL_ARG4(&regs->regs));
346                 else
347                         audit_syscall_exit(current, 
348                                            UPT_SYSCALL_RET(&regs->regs));
349         }
350
351         /* Fake a debug trap */
352         if (is_singlestep)
353                 send_sigtrap(current, regs, 0);
354
355         if (!test_thread_flag(TIF_SYSCALL_TRACE))
356                 return;
357
358         if (!(current->ptrace & PT_PTRACED))
359                 return;
360
361         /* the 0x80 provides a way for the tracing parent to distinguish
362            between a syscall stop and SIGTRAP delivery */
363         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
364         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
365
366         if (entryexit) /* force do_signal() --> is_syscall() */
367                 set_thread_flag(TIF_SIGPENDING);
368
369         /* this isn't the same as continuing with a signal, but it will do
370          * for normal use.  strace only continues with a signal if the
371          * stopping signal is not SIGTRAP.  -brl
372          */
373         if (current->exit_code) {
374                 send_sig(current->exit_code, current, 1);
375                 current->exit_code = 0;
376         }
377 }
378
379 /*
380  * Overrides for Emacs so that we follow Linus's tabbing style.
381  * Emacs will notice this stuff at the end of the file and automatically
382  * adjust the settings for this buffer only.  This must remain at the end
383  * of the file.
384  * ---------------------------------------------------------------------------
385  * Local variables:
386  * c-file-style: "linux"
387  * End:
388  */