1 /*	$NetBSD: linux_ptrace.c,v 1.9 2001/11/15 09:48:00 lukem Exp $ */
2 
3 /*-
4  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Matthias Scheler and Emmanuel Dreyfus.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.9 2001/11/15 09:48:00 lukem Exp $");
41 
42 #include <sys/param.h>
43 #include <sys/malloc.h>
44 #include <sys/mount.h>
45 #include <sys/proc.h>
46 #include <sys/ptrace.h>
47 #include <sys/systm.h>
48 #include <sys/syscallargs.h>
49 #include <uvm/uvm_extern.h>
50 
51 #include <machine/reg.h>
52 
53 #include <compat/linux/common/linux_types.h>
54 #include <compat/linux/common/linux_ptrace.h>
55 #include <compat/linux/common/linux_signal.h>
56 
57 #include <compat/linux/common/linux_util.h>
58 #include <compat/linux/common/linux_machdep.h>
59 #include <compat/linux/common/linux_emuldata.h>
60 #include <compat/linux/common/linux_exec.h>	/* for emul_linux */
61 
62 #include <compat/linux/linux_syscallargs.h>
63 
64 #include <lib/libkern/libkern.h>	/* for offsetof() */
65 
66 /*
67  * From Linux's include/asm-ppc/ptrace.h.
68  * structure used for storing reg context:  defined in linux_machdep.h
69  * structure used for storing floating point context:
70  * Linux just uses a double fpr[32], no struct
71  */
72 
73 /*
74  * user struct for linux process - this is used for Linux ptrace emulation
75  * most of it is junk only used by gdb
76  *
77  * From Linux's include/asm-ppc/user.h
78  *
79  * XXX u_ar0 was a struct reg in Linux/powerpc
80  * Can't find out what a struct regs is for Linux/powerpc,
81  * so we use a struct pt_regs instead. don't know if this is right.
82  */
83 
84 struct linux_user {
85 	struct linux_pt_regs regs;
86 #define lusr_startgdb regs
87 	size_t u_tsize;
88 	size_t u_dsize;
89 	size_t u_ssize;
90 	unsigned long start_code;
91 	unsigned long start_data;
92 	unsigned long start_stack;
93 	long int signal;
94 	struct linux_pt_regs *u_ar0;		/* help gdb find registers */
95 	unsigned long magic;
96 	char u_comm[32];
97 #define lu_comm_end u_comm[31]
98 };
99 
100 #define LUSR_OFF(member) offsetof(struct linux_user, member)
101 #define LUSR_REG_OFF(member) offsetof(struct linux_pt_regs, member)
102 #define ISSET(t, f) ((t) & (f))
103 
104 int
105 linux_sys_ptrace_arch(p, v, retval)	/* XXX Check me! (From NetBSD/i386) */
106 	struct proc *p;
107 	void *v;
108 	register_t *retval;
109 {
110 	struct linux_sys_ptrace_args /* {
111 		syscallarg(int) request;
112 		syscallarg(int) pid;
113 		syscallarg(int) addr;
114 		syscallarg(int) data;
115 	} */ *uap = v;
116 	int request, error;
117 	struct proc *t;				/* target process */
118 	struct reg *regs = NULL;
119 	struct fpreg *fpregs = NULL;
120 	struct linux_pt_regs *linux_regs = NULL;
121 	double *linux_fpreg = NULL;  /* it's an array, not a struct */
122 	int addr;
123 	int i;
124 
125 	switch (request = SCARG(uap, request)) {
126 		case LINUX_PTRACE_PEEKUSR:
127 		case LINUX_PTRACE_POKEUSR:
128 		case LINUX_PTRACE_GETREGS:
129 		case LINUX_PTRACE_SETREGS:
130 		case LINUX_PTRACE_GETFPREGS:
131 		case LINUX_PTRACE_SETFPREGS:
132 			break;
133 		default:
134 			return EIO;
135 	}
136 
137 	/* Find the process we're supposed to be operating on. */
138 	if ((t = pfind(SCARG(uap, pid))) == NULL)
139 		return ESRCH;
140 
141 	/*
142 	 * You can't do what you want to the process if:
143 	 *	(1) It's not being traced at all,
144 	 */
145 	if (!ISSET(t->p_flag, P_TRACED))
146 		return EPERM;
147 
148 	/*
149 	 *	(2) it's being traced by procfs (which has
150 	 *		 different signal delivery semantics),
151 	 */
152 	if (ISSET(t->p_flag, P_FSTRACE))
153 		return EBUSY;
154 
155 	/*
156 	 *	(3) it's not being traced by _you_, or
157 	 */
158 	if (t->p_pptr != p)
159 		return EBUSY;
160 
161 	/*
162 	 *	(4) it's not currently stopped.
163 	 */
164 	if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED))
165 		return EBUSY;
166 
167 	*retval = 0;
168 
169 	switch (request) {
170 	case  LINUX_PTRACE_GETREGS:
171 		MALLOC(regs, struct reg*, sizeof(struct reg), M_TEMP, M_WAITOK);
172 		MALLOC(linux_regs, struct linux_pt_regs*, sizeof(*linux_regs),
173 		    M_TEMP, M_WAITOK);
174 
175 		error = process_read_regs(t, regs);
176 		if (error != 0)
177 			goto out;
178 
179 		for (i=0; i<=31; i++)
180 			linux_regs->lgpr[i] = regs->fixreg[i];
181 		linux_regs->lnip = regs->pc;
182 		linux_regs->lmsr = 0;
183 		/* XXX Is that right? */
184 		linux_regs->lorig_gpr3 = regs->fixreg[3];
185 		linux_regs->lctr = regs->ctr;
186 		linux_regs->llink = regs->lr;
187 		linux_regs->lxer = regs->xer;
188 		linux_regs->lccr = regs->cr;
189 		linux_regs->lmq = 0;
190 		linux_regs->ltrap = 0;
191 		linux_regs->ldar = 0;
192 		linux_regs->ldsisr = 0;
193 		linux_regs->lresult = 0;
194 
195 		error = copyout(linux_regs, (caddr_t)SCARG(uap, data),
196 			 sizeof(struct linux_pt_regs));
197 		goto out;
198 
199 	case  LINUX_PTRACE_SETREGS:
200 		MALLOC(regs, struct reg*, sizeof(struct reg), M_TEMP, M_WAITOK);
201 		MALLOC(linux_regs, struct linux_pt_regs*, sizeof(*linux_regs),
202 		    M_TEMP, M_WAITOK);
203 
204 		error = copyin((caddr_t)SCARG(uap, data), linux_regs,
205 			 sizeof(struct linux_pt_regs));
206 		if (error != 0)
207 			goto out;
208 
209 		for (i=0; i<=31; i++)
210 			regs->fixreg[i] = linux_regs->lgpr[i];
211 		regs->lr = linux_regs->llink;
212 		regs->cr = linux_regs->lccr;
213 		regs->xer = linux_regs->lxer;
214 		regs->ctr = linux_regs->lctr;
215 		regs->pc = linux_regs->lnip; /* XXX */
216 
217 		error = process_write_regs(t, regs);
218 		goto out;
219 
220 	case  LINUX_PTRACE_GETFPREGS:
221 		MALLOC(fpregs, struct fpreg *, sizeof(struct fpreg),
222 		    M_TEMP, M_WAITOK);
223 		MALLOC(linux_fpreg, double *,
224 		    32*sizeof(double), M_TEMP, M_WAITOK);
225 
226 		error = process_read_fpregs(t, fpregs);
227 		if (error != 0)
228 			goto out;
229 
230 		/* zero the contents if NetBSD fpreg structure is smaller */
231 		if (sizeof(struct fpreg) < (32*sizeof(double)))
232 			memset(linux_fpreg, '\0', (32*sizeof(double)));
233 
234 		memcpy(linux_fpreg, fpregs,
235 			min(32*sizeof(double), sizeof(struct fpreg)));
236 		error = copyout(linux_fpreg, (caddr_t)SCARG(uap, data),
237 			 32*sizeof(double));
238 		goto out;
239 
240 	case  LINUX_PTRACE_SETFPREGS:
241 		MALLOC(fpregs, struct fpreg *, sizeof(struct fpreg),
242 		    M_TEMP, M_WAITOK);
243 		MALLOC(linux_fpreg, double *,
244 		    32*sizeof(double), M_TEMP, M_WAITOK);
245 		error = copyin((caddr_t)SCARG(uap, data), linux_fpreg,
246 			 32*sizeof(double));
247 		if (error != 0)
248 			goto out;
249 
250 		memset(fpregs, '\0', sizeof(struct fpreg));
251 		memcpy(fpregs, linux_fpreg,
252 		    min(32*sizeof(double), sizeof(struct fpreg)));
253 
254 		error = process_write_fpregs(t, fpregs);
255 		goto out;
256 
257 	case  LINUX_PTRACE_PEEKUSR:
258 		addr = SCARG(uap, addr);
259 		MALLOC(regs, struct reg*, sizeof(struct reg), M_TEMP, M_WAITOK);
260 		error = process_read_regs(t, regs);
261 		if (error)
262 			goto out;
263 
264 		PHOLD(t);	/* need full process info */
265 		error = 0;
266 		if ((addr < LUSR_OFF(lusr_startgdb)) ||
267 		    (addr > LUSR_OFF(lu_comm_end)))
268 		 	error = 1;
269 		else if (addr == LUSR_OFF(u_tsize))
270 			*retval = p->p_vmspace->vm_tsize;
271 		else if (addr == LUSR_OFF(u_dsize))
272 			*retval = p->p_vmspace->vm_dsize;
273 		else if (addr == LUSR_OFF(u_ssize))
274 			*retval = p->p_vmspace->vm_ssize;
275 		else if (addr == LUSR_OFF(start_code))
276 			*retval = (register_t) p->p_vmspace->vm_taddr;
277 		else if (addr == LUSR_OFF(start_stack))
278 			*retval = (register_t) p->p_vmspace->vm_minsaddr;
279 		else if ((addr >= LUSR_REG_OFF(lpt_regs_fixreg_begin)) &&
280 		    (addr <= LUSR_REG_OFF(lpt_regs_fixreg_end)))
281 			*retval = regs->fixreg[addr / sizeof (register_t)];
282 		else if (addr == LUSR_REG_OFF(lnip))
283 			*retval = regs->pc;
284 		else if (addr == LUSR_REG_OFF(lctr))
285 			*retval = regs->ctr;
286 		else if (addr == LUSR_REG_OFF(llink))
287 			*retval = regs->lr;
288 		else if (addr == LUSR_REG_OFF(lxer))
289 			*retval = regs->xer;
290 		else if (addr == LUSR_REG_OFF(lccr))
291 			*retval = regs->cr;
292 		else if (addr == LUSR_OFF(signal))
293 			error = 1;
294 		else if (addr == LUSR_OFF(signal))
295 			error = 1;
296 		else if (addr == LUSR_OFF(magic))
297 			error = 1;
298 		else if (addr == LUSR_OFF(u_comm))
299 			error = 1;
300 		else {
301 #ifdef DEBUG_LINUX
302 			printf("linux_ptrace: unsupported address: %d\n", addr);
303 #endif
304 			error = 1;
305 		}
306 
307 		PRELE(t);
308 
309 		if (error)
310 			goto out;
311 
312 		error = copyout (retval,
313 		    (caddr_t)SCARG(uap, data), sizeof retval);
314 		*retval = SCARG(uap, data);
315 
316 		goto out;
317 
318 		break;
319 
320 	case  LINUX_PTRACE_POKEUSR: /* XXX Not tested */
321 		addr = SCARG(uap, addr);
322 		MALLOC(regs, struct reg*, sizeof(struct reg), M_TEMP, M_WAITOK);
323 		error = process_read_regs(t, regs);
324 		if (error)
325 			goto out;
326 
327 		PHOLD(t);       /* need full process info */
328 		error = 0;
329 		if ((addr < LUSR_OFF(lusr_startgdb)) ||
330 		    (addr > LUSR_OFF(lu_comm_end)))
331 		 	error = 1;
332 		else if (addr == LUSR_OFF(u_tsize))
333 			error = 1;
334 		else if (addr == LUSR_OFF(u_dsize))
335 			error = 1;
336 		else if (addr == LUSR_OFF(u_ssize))
337 			error = 1;
338 		else if (addr == LUSR_OFF(start_code))
339 			error = 1;
340 		else if (addr == LUSR_OFF(start_stack))
341 			error = 1;
342 		else if ((addr >= LUSR_REG_OFF(lpt_regs_fixreg_begin)) &&
343 		    (addr <= LUSR_REG_OFF(lpt_regs_fixreg_end)))
344 			regs->fixreg[addr / sizeof (register_t)] =
345 			    (register_t)SCARG(uap, data);
346 		else if (addr == LUSR_REG_OFF(lnip))
347 			regs->pc = (register_t)SCARG(uap, data);
348 		else if (addr == LUSR_REG_OFF(lctr))
349 			regs->ctr = (register_t)SCARG(uap, data);
350 		else if (addr == LUSR_REG_OFF(llink))
351 			regs->lr = (register_t)SCARG(uap, data);
352 		else if (addr == LUSR_REG_OFF(lxer))
353 			regs->xer = (register_t)SCARG(uap, data);
354 		else if (addr == LUSR_REG_OFF(lccr))
355 			regs->cr = (register_t)SCARG(uap, data);
356 		else if (addr == LUSR_OFF(signal))
357 			error = 1;
358 		else if (addr == LUSR_OFF(magic))
359 			error = 1;
360 		else if (addr == LUSR_OFF(u_comm))
361 			error = 1;
362 		else {
363 #ifdef DEBUG_LINUX
364 			printf("linux_ptrace: unsupported address: %d\n", addr);
365 #endif
366 			error = 1;
367 		}
368 
369 		PRELE(t);
370 
371 		error = process_write_regs(t,regs);
372 		if (error)
373 			goto out;
374 
375 		break;
376 	default:
377 		/* never reached */
378 		break;
379 	}
380 	return EIO;
381 
382 	 out:
383 	if (regs)
384 		FREE(regs, M_TEMP);
385 	if (fpregs)
386 		FREE(fpregs, M_TEMP);
387 	if (linux_regs)
388 		FREE(linux_regs, M_TEMP);
389 	if (linux_fpreg)
390 		FREE(linux_fpreg, M_TEMP);
391 	return (error);
392 }
393