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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2000-2003, Axis Communications AB. | |
3 | */ | |
4 | ||
5 | #include <linux/kernel.h> | |
6 | #include <linux/sched.h> | |
7 | #include <linux/mm.h> | |
8 | #include <linux/smp.h> | |
9 | #include <linux/smp_lock.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/ptrace.h> | |
12 | #include <linux/user.h> | |
7ed20e1a | 13 | #include <linux/signal.h> |
1da177e4 LT |
14 | |
15 | #include <asm/uaccess.h> | |
16 | #include <asm/page.h> | |
17 | #include <asm/pgtable.h> | |
18 | #include <asm/system.h> | |
19 | #include <asm/processor.h> | |
20 | ||
21 | /* | |
22 | * Determines which bits in DCCR the user has access to. | |
23 | * 1 = access, 0 = no access. | |
24 | */ | |
25 | #define DCCR_MASK 0x0000001f /* XNZVC */ | |
26 | ||
27 | /* | |
28 | * Get contents of register REGNO in task TASK. | |
29 | */ | |
30 | inline long get_reg(struct task_struct *task, unsigned int regno) | |
31 | { | |
32 | /* USP is a special case, it's not in the pt_regs struct but | |
33 | * in the tasks thread struct | |
34 | */ | |
35 | ||
36 | if (regno == PT_USP) | |
37 | return task->thread.usp; | |
38 | else if (regno < PT_MAX) | |
39 | return ((unsigned long *)user_regs(task->thread_info))[regno]; | |
40 | else | |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* | |
45 | * Write contents of register REGNO in task TASK. | |
46 | */ | |
47 | inline int put_reg(struct task_struct *task, unsigned int regno, | |
48 | unsigned long data) | |
49 | { | |
50 | if (regno == PT_USP) | |
51 | task->thread.usp = data; | |
52 | else if (regno < PT_MAX) | |
53 | ((unsigned long *)user_regs(task->thread_info))[regno] = data; | |
54 | else | |
55 | return -1; | |
56 | return 0; | |
57 | } | |
58 | ||
59 | /* | |
60 | * Called by kernel/ptrace.c when detaching. | |
61 | * | |
62 | * Make sure the single step bit is not set. | |
63 | */ | |
64 | void | |
65 | ptrace_disable(struct task_struct *child) | |
66 | { | |
67 | /* Todo - pending singlesteps? */ | |
68 | } | |
69 | ||
70 | /* | |
71 | * Note that this implementation of ptrace behaves differently from vanilla | |
72 | * ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT, | |
73 | * PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not | |
74 | * ignored. Instead, the data variable is expected to point at a location | |
75 | * (in user space) where the result of the ptrace call is written (instead of | |
76 | * being returned). | |
77 | */ | |
78 | asmlinkage int | |
79 | sys_ptrace(long request, long pid, long addr, long data) | |
80 | { | |
81 | struct task_struct *child; | |
82 | int ret; | |
83 | unsigned long __user *datap = (unsigned long __user *)data; | |
84 | ||
85 | lock_kernel(); | |
86 | ret = -EPERM; | |
87 | ||
88 | if (request == PTRACE_TRACEME) { | |
89 | if (current->ptrace & PT_PTRACED) | |
90 | goto out; | |
91 | ||
92 | current->ptrace |= PT_PTRACED; | |
93 | ret = 0; | |
94 | goto out; | |
95 | } | |
96 | ||
97 | ret = -ESRCH; | |
98 | read_lock(&tasklist_lock); | |
99 | child = find_task_by_pid(pid); | |
100 | ||
101 | if (child) | |
102 | get_task_struct(child); | |
103 | ||
104 | read_unlock(&tasklist_lock); | |
105 | ||
106 | if (!child) | |
107 | goto out; | |
108 | ||
109 | ret = -EPERM; | |
110 | ||
111 | if (pid == 1) /* Leave the init process alone! */ | |
112 | goto out_tsk; | |
113 | ||
114 | if (request == PTRACE_ATTACH) { | |
115 | ret = ptrace_attach(child); | |
116 | goto out_tsk; | |
117 | } | |
118 | ||
119 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
120 | if (ret < 0) | |
121 | goto out_tsk; | |
122 | ||
123 | switch (request) { | |
124 | /* Read word at location address. */ | |
125 | case PTRACE_PEEKTEXT: | |
126 | case PTRACE_PEEKDATA: { | |
127 | unsigned long tmp; | |
128 | int copied; | |
129 | ||
130 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
131 | ret = -EIO; | |
132 | ||
133 | if (copied != sizeof(tmp)) | |
134 | break; | |
135 | ||
136 | ret = put_user(tmp,datap); | |
137 | break; | |
138 | } | |
139 | ||
140 | /* Read the word at location address in the USER area. */ | |
141 | case PTRACE_PEEKUSR: { | |
142 | unsigned long tmp; | |
143 | ||
144 | ret = -EIO; | |
145 | if ((addr & 3) || addr < 0 || addr > PT_MAX << 2) | |
146 | break; | |
147 | ||
148 | tmp = get_reg(child, addr >> 2); | |
149 | ret = put_user(tmp, datap); | |
150 | break; | |
151 | } | |
152 | ||
153 | /* Write the word at location address. */ | |
154 | case PTRACE_POKETEXT: | |
155 | case PTRACE_POKEDATA: | |
156 | ret = 0; | |
157 | ||
158 | if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) | |
159 | break; | |
160 | ||
161 | ret = -EIO; | |
162 | break; | |
163 | ||
164 | /* Write the word at location address in the USER area. */ | |
165 | case PTRACE_POKEUSR: | |
166 | ret = -EIO; | |
167 | if ((addr & 3) || addr < 0 || addr > PT_MAX << 2) | |
168 | break; | |
169 | ||
170 | addr >>= 2; | |
171 | ||
172 | if (addr == PT_DCCR) { | |
173 | /* don't allow the tracing process to change stuff like | |
174 | * interrupt enable, kernel/user bit, dma enables etc. | |
175 | */ | |
176 | data &= DCCR_MASK; | |
177 | data |= get_reg(child, PT_DCCR) & ~DCCR_MASK; | |
178 | } | |
179 | if (put_reg(child, addr, data)) | |
180 | break; | |
181 | ret = 0; | |
182 | break; | |
183 | ||
184 | case PTRACE_SYSCALL: | |
185 | case PTRACE_CONT: | |
186 | ret = -EIO; | |
187 | ||
7ed20e1a | 188 | if (!valid_signal(data)) |
1da177e4 LT |
189 | break; |
190 | ||
191 | if (request == PTRACE_SYSCALL) { | |
192 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
193 | } | |
194 | else { | |
195 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
196 | } | |
197 | ||
198 | child->exit_code = data; | |
199 | ||
200 | /* TODO: make sure any pending breakpoint is killed */ | |
201 | wake_up_process(child); | |
202 | ret = 0; | |
203 | ||
204 | break; | |
205 | ||
206 | /* Make the child exit by sending it a sigkill. */ | |
207 | case PTRACE_KILL: | |
208 | ret = 0; | |
209 | ||
210 | if (child->state == TASK_ZOMBIE) | |
211 | break; | |
212 | ||
213 | child->exit_code = SIGKILL; | |
214 | ||
215 | /* TODO: make sure any pending breakpoint is killed */ | |
216 | wake_up_process(child); | |
217 | break; | |
218 | ||
219 | /* Set the trap flag. */ | |
220 | case PTRACE_SINGLESTEP: | |
221 | ret = -EIO; | |
222 | ||
7ed20e1a | 223 | if (!valid_signal(data)) |
1da177e4 LT |
224 | break; |
225 | ||
226 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
227 | ||
228 | /* TODO: set some clever breakpoint mechanism... */ | |
229 | ||
230 | child->exit_code = data; | |
231 | wake_up_process(child); | |
232 | ret = 0; | |
233 | break; | |
234 | ||
235 | case PTRACE_DETACH: | |
236 | ret = ptrace_detach(child, data); | |
237 | break; | |
238 | ||
239 | /* Get all GP registers from the child. */ | |
240 | case PTRACE_GETREGS: { | |
241 | int i; | |
242 | unsigned long tmp; | |
243 | ||
244 | for (i = 0; i <= PT_MAX; i++) { | |
245 | tmp = get_reg(child, i); | |
246 | ||
247 | if (put_user(tmp, datap)) { | |
248 | ret = -EFAULT; | |
249 | goto out_tsk; | |
250 | } | |
251 | ||
252 | data += sizeof(long); | |
253 | } | |
254 | ||
255 | ret = 0; | |
256 | break; | |
257 | } | |
258 | ||
259 | /* Set all GP registers in the child. */ | |
260 | case PTRACE_SETREGS: { | |
261 | int i; | |
262 | unsigned long tmp; | |
263 | ||
264 | for (i = 0; i <= PT_MAX; i++) { | |
265 | if (get_user(tmp, datap)) { | |
266 | ret = -EFAULT; | |
267 | goto out_tsk; | |
268 | } | |
269 | ||
270 | if (i == PT_DCCR) { | |
271 | tmp &= DCCR_MASK; | |
272 | tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK; | |
273 | } | |
274 | ||
275 | put_reg(child, i, tmp); | |
276 | data += sizeof(long); | |
277 | } | |
278 | ||
279 | ret = 0; | |
280 | break; | |
281 | } | |
282 | ||
283 | default: | |
284 | ret = ptrace_request(child, request, addr, data); | |
285 | break; | |
286 | } | |
287 | out_tsk: | |
288 | put_task_struct(child); | |
289 | out: | |
290 | unlock_kernel(); | |
291 | return ret; | |
292 | } | |
293 | ||
294 | void do_syscall_trace(void) | |
295 | { | |
296 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) | |
297 | return; | |
298 | ||
299 | if (!(current->ptrace & PT_PTRACED)) | |
300 | return; | |
301 | ||
302 | /* the 0x80 provides a way for the tracing parent to distinguish | |
303 | between a syscall stop and SIGTRAP delivery */ | |
304 | ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) | |
305 | ? 0x80 : 0)); | |
306 | ||
307 | /* | |
308 | * This isn't the same as continuing with a signal, but it will do for | |
309 | * normal use. | |
310 | */ | |
311 | if (current->exit_code) { | |
312 | send_sig(current->exit_code, current, 1); | |
313 | current->exit_code = 0; | |
314 | } | |
315 | } |