linux_ptrace.c revision 276084 
1/*-
2 * Copyright (c) 2001 Alexander Kabaev
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/10/sys/i386/linux/linux_ptrace.c 276084 2014-12-22 21:32:39Z jhb $");
31
32#include "opt_cpu.h"
33
34#include <sys/param.h>
35#include <sys/lock.h>
36#include <sys/mutex.h>
37#include <sys/proc.h>
38#include <sys/ptrace.h>
39#include <sys/syscallsubr.h>
40#include <sys/systm.h>
41
42#include <machine/md_var.h>
43#include <machine/pcb.h>
44#include <machine/reg.h>
45
46#include <i386/linux/linux.h>
47#include <i386/linux/linux_proto.h>
48#include <compat/linux/linux_signal.h>
49
50#if !defined(CPU_DISABLE_SSE) && defined(I686_CPU)
51#define CPU_ENABLE_SSE
52#endif
53
54/*
55 *   Linux ptrace requests numbers. Mostly identical to FreeBSD,
56 *   except for MD ones and PT_ATTACH/PT_DETACH.
57 */
58#define	PTRACE_TRACEME		0
59#define	PTRACE_PEEKTEXT		1
60#define	PTRACE_PEEKDATA		2
61#define	PTRACE_PEEKUSR		3
62#define	PTRACE_POKETEXT		4
63#define	PTRACE_POKEDATA		5
64#define	PTRACE_POKEUSR		6
65#define	PTRACE_CONT		7
66#define	PTRACE_KILL		8
67#define	PTRACE_SINGLESTEP	9
68
69#define PTRACE_ATTACH		16
70#define PTRACE_DETACH		17
71
72#define	PTRACE_SYSCALL		24
73
74#define PTRACE_GETREGS		12
75#define PTRACE_SETREGS		13
76#define PTRACE_GETFPREGS	14
77#define PTRACE_SETFPREGS	15
78#define PTRACE_GETFPXREGS	18
79#define PTRACE_SETFPXREGS	19
80
81#define PTRACE_SETOPTIONS	21
82
83/*
84 * Linux keeps debug registers at the following
85 * offset in the user struct
86 */
87#define LINUX_DBREG_OFFSET	252
88#define LINUX_DBREG_SIZE	(8*sizeof(l_int))
89
90static __inline int
91map_signum(int signum)
92{
93
94	if (signum > 0 && signum <= LINUX_SIGTBLSZ)
95		signum = linux_to_bsd_signal[_SIG_IDX(signum)];
96	return ((signum == SIGSTOP)? 0 : signum);
97}
98
99struct linux_pt_reg {
100	l_long	ebx;
101	l_long	ecx;
102	l_long	edx;
103	l_long	esi;
104	l_long	edi;
105	l_long	ebp;
106	l_long	eax;
107	l_int	xds;
108	l_int	xes;
109	l_int	xfs;
110	l_int	xgs;
111	l_long	orig_eax;
112	l_long	eip;
113	l_int	xcs;
114	l_long	eflags;
115	l_long	esp;
116	l_int	xss;
117};
118
119/*
120 *   Translate i386 ptrace registers between Linux and FreeBSD formats.
121 *   The translation is pretty straighforward, for all registers, but
122 *   orig_eax on Linux side and r_trapno and r_err in FreeBSD
123 */
124static void
125map_regs_to_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
126{
127	linux_r->ebx = bsd_r->r_ebx;
128	linux_r->ecx = bsd_r->r_ecx;
129	linux_r->edx = bsd_r->r_edx;
130	linux_r->esi = bsd_r->r_esi;
131	linux_r->edi = bsd_r->r_edi;
132	linux_r->ebp = bsd_r->r_ebp;
133	linux_r->eax = bsd_r->r_eax;
134	linux_r->xds = bsd_r->r_ds;
135	linux_r->xes = bsd_r->r_es;
136	linux_r->xfs = bsd_r->r_fs;
137	linux_r->xgs = bsd_r->r_gs;
138	linux_r->orig_eax = bsd_r->r_eax;
139	linux_r->eip = bsd_r->r_eip;
140	linux_r->xcs = bsd_r->r_cs;
141	linux_r->eflags = bsd_r->r_eflags;
142	linux_r->esp = bsd_r->r_esp;
143	linux_r->xss = bsd_r->r_ss;
144}
145
146static void
147map_regs_from_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
148{
149	bsd_r->r_ebx = linux_r->ebx;
150	bsd_r->r_ecx = linux_r->ecx;
151	bsd_r->r_edx = linux_r->edx;
152	bsd_r->r_esi = linux_r->esi;
153	bsd_r->r_edi = linux_r->edi;
154	bsd_r->r_ebp = linux_r->ebp;
155	bsd_r->r_eax = linux_r->eax;
156	bsd_r->r_ds  = linux_r->xds;
157	bsd_r->r_es  = linux_r->xes;
158	bsd_r->r_fs  = linux_r->xfs;
159	bsd_r->r_gs  = linux_r->xgs;
160	bsd_r->r_eip = linux_r->eip;
161	bsd_r->r_cs  = linux_r->xcs;
162	bsd_r->r_eflags = linux_r->eflags;
163	bsd_r->r_esp = linux_r->esp;
164	bsd_r->r_ss = linux_r->xss;
165}
166
167struct linux_pt_fpreg {
168	l_long cwd;
169	l_long swd;
170	l_long twd;
171	l_long fip;
172	l_long fcs;
173	l_long foo;
174	l_long fos;
175	l_long st_space[2*10];
176};
177
178static void
179map_fpregs_to_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
180{
181	linux_r->cwd = bsd_r->fpr_env[0];
182	linux_r->swd = bsd_r->fpr_env[1];
183	linux_r->twd = bsd_r->fpr_env[2];
184	linux_r->fip = bsd_r->fpr_env[3];
185	linux_r->fcs = bsd_r->fpr_env[4];
186	linux_r->foo = bsd_r->fpr_env[5];
187	linux_r->fos = bsd_r->fpr_env[6];
188	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(linux_r->st_space));
189}
190
191static void
192map_fpregs_from_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
193{
194	bsd_r->fpr_env[0] = linux_r->cwd;
195	bsd_r->fpr_env[1] = linux_r->swd;
196	bsd_r->fpr_env[2] = linux_r->twd;
197	bsd_r->fpr_env[3] = linux_r->fip;
198	bsd_r->fpr_env[4] = linux_r->fcs;
199	bsd_r->fpr_env[5] = linux_r->foo;
200	bsd_r->fpr_env[6] = linux_r->fos;
201	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(bsd_r->fpr_acc));
202}
203
204struct linux_pt_fpxreg {
205	l_ushort	cwd;
206	l_ushort	swd;
207	l_ushort	twd;
208	l_ushort	fop;
209	l_long		fip;
210	l_long		fcs;
211	l_long		foo;
212	l_long		fos;
213	l_long		mxcsr;
214	l_long		reserved;
215	l_long		st_space[32];
216	l_long		xmm_space[32];
217	l_long		padding[56];
218};
219
220#ifdef CPU_ENABLE_SSE
221static int
222linux_proc_read_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
223{
224
225	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
226	if (cpu_fxsr == 0 || (td->td_proc->p_flag & P_INMEM) == 0)
227		return (EIO);
228	bcopy(&get_pcb_user_save_td(td)->sv_xmm, fpxregs, sizeof(*fpxregs));
229	return (0);
230}
231
232static int
233linux_proc_write_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
234{
235
236	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
237	if (cpu_fxsr == 0 || (td->td_proc->p_flag & P_INMEM) == 0)
238		return (EIO);
239	bcopy(fpxregs, &get_pcb_user_save_td(td)->sv_xmm, sizeof(*fpxregs));
240	return (0);
241}
242#endif
243
244int
245linux_ptrace(struct thread *td, struct linux_ptrace_args *uap)
246{
247	union {
248		struct linux_pt_reg	reg;
249		struct linux_pt_fpreg	fpreg;
250		struct linux_pt_fpxreg	fpxreg;
251	} r;
252	union {
253		struct reg		bsd_reg;
254		struct fpreg		bsd_fpreg;
255		struct dbreg		bsd_dbreg;
256	} u;
257	void *addr;
258	pid_t pid;
259	int error, req;
260
261	error = 0;
262
263	/* by default, just copy data intact */
264	req  = uap->req;
265	pid  = (pid_t)uap->pid;
266	addr = (void *)uap->addr;
267
268	switch (req) {
269	case PTRACE_TRACEME:
270	case PTRACE_POKETEXT:
271	case PTRACE_POKEDATA:
272	case PTRACE_KILL:
273		error = kern_ptrace(td, req, pid, addr, uap->data);
274		break;
275	case PTRACE_PEEKTEXT:
276	case PTRACE_PEEKDATA: {
277		/* need to preserve return value */
278		int rval = td->td_retval[0];
279		error = kern_ptrace(td, req, pid, addr, 0);
280		if (error == 0)
281			error = copyout(td->td_retval, (void *)uap->data,
282			    sizeof(l_int));
283		td->td_retval[0] = rval;
284		break;
285	}
286	case PTRACE_DETACH:
287		error = kern_ptrace(td, PT_DETACH, pid, (void *)1,
288		     map_signum(uap->data));
289		break;
290	case PTRACE_SINGLESTEP:
291	case PTRACE_CONT:
292		error = kern_ptrace(td, req, pid, (void *)1,
293		     map_signum(uap->data));
294		break;
295	case PTRACE_ATTACH:
296		error = kern_ptrace(td, PT_ATTACH, pid, addr, uap->data);
297		break;
298	case PTRACE_GETREGS:
299		/* Linux is using data where FreeBSD is using addr */
300		error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
301		if (error == 0) {
302			map_regs_to_linux(&u.bsd_reg, &r.reg);
303			error = copyout(&r.reg, (void *)uap->data,
304			    sizeof(r.reg));
305		}
306		break;
307	case PTRACE_SETREGS:
308		/* Linux is using data where FreeBSD is using addr */
309		error = copyin((void *)uap->data, &r.reg, sizeof(r.reg));
310		if (error == 0) {
311			map_regs_from_linux(&u.bsd_reg, &r.reg);
312			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
313		}
314		break;
315	case PTRACE_GETFPREGS:
316		/* Linux is using data where FreeBSD is using addr */
317		error = kern_ptrace(td, PT_GETFPREGS, pid, &u.bsd_fpreg, 0);
318		if (error == 0) {
319			map_fpregs_to_linux(&u.bsd_fpreg, &r.fpreg);
320			error = copyout(&r.fpreg, (void *)uap->data,
321			    sizeof(r.fpreg));
322		}
323		break;
324	case PTRACE_SETFPREGS:
325		/* Linux is using data where FreeBSD is using addr */
326		error = copyin((void *)uap->data, &r.fpreg, sizeof(r.fpreg));
327		if (error == 0) {
328			map_fpregs_from_linux(&u.bsd_fpreg, &r.fpreg);
329			error = kern_ptrace(td, PT_SETFPREGS, pid,
330			    &u.bsd_fpreg, 0);
331		}
332		break;
333	case PTRACE_SETFPXREGS:
334#ifdef CPU_ENABLE_SSE
335		error = copyin((void *)uap->data, &r.fpxreg, sizeof(r.fpxreg));
336		if (error)
337			break;
338#endif
339		/* FALL THROUGH */
340	case PTRACE_GETFPXREGS: {
341#ifdef CPU_ENABLE_SSE
342		struct proc *p;
343		struct thread *td2;
344
345		if (sizeof(struct linux_pt_fpxreg) != sizeof(struct savexmm)) {
346			static int once = 0;
347			if (!once) {
348				printf("linux: savexmm != linux_pt_fpxreg\n");
349				once = 1;
350			}
351			error = EIO;
352			break;
353		}
354
355		if ((p = pfind(uap->pid)) == NULL) {
356			error = ESRCH;
357			break;
358		}
359
360		/* Exiting processes can't be debugged. */
361		if ((p->p_flag & P_WEXIT) != 0) {
362			error = ESRCH;
363			goto fail;
364		}
365
366		if ((error = p_candebug(td, p)) != 0)
367			goto fail;
368
369		/* System processes can't be debugged. */
370		if ((p->p_flag & P_SYSTEM) != 0) {
371			error = EINVAL;
372			goto fail;
373		}
374
375		/* not being traced... */
376		if ((p->p_flag & P_TRACED) == 0) {
377			error = EPERM;
378			goto fail;
379		}
380
381		/* not being traced by YOU */
382		if (p->p_pptr != td->td_proc) {
383			error = EBUSY;
384			goto fail;
385		}
386
387		/* not currently stopped */
388		if (!P_SHOULDSTOP(p) || (p->p_flag & P_WAITED) == 0) {
389			error = EBUSY;
390			goto fail;
391		}
392
393		if (req == PTRACE_GETFPXREGS) {
394			_PHOLD(p);	/* may block */
395			td2 = FIRST_THREAD_IN_PROC(p);
396			error = linux_proc_read_fpxregs(td2, &r.fpxreg);
397			_PRELE(p);
398			PROC_UNLOCK(p);
399			if (error == 0)
400				error = copyout(&r.fpxreg, (void *)uap->data,
401				    sizeof(r.fpxreg));
402		} else {
403			/* clear dangerous bits exactly as Linux does*/
404			r.fpxreg.mxcsr &= 0xffbf;
405			_PHOLD(p);	/* may block */
406			td2 = FIRST_THREAD_IN_PROC(p);
407			error = linux_proc_write_fpxregs(td2, &r.fpxreg);
408			_PRELE(p);
409			PROC_UNLOCK(p);
410		}
411		break;
412
413	fail:
414		PROC_UNLOCK(p);
415#else
416		error = EIO;
417#endif
418		break;
419	}
420	case PTRACE_PEEKUSR:
421	case PTRACE_POKEUSR: {
422		error = EIO;
423
424		/* check addr for alignment */
425		if (uap->addr < 0 || uap->addr & (sizeof(l_int) - 1))
426			break;
427		/*
428		 * Allow linux programs to access register values in
429		 * user struct. We simulate this through PT_GET/SETREGS
430		 * as necessary.
431		 */
432		if (uap->addr < sizeof(struct linux_pt_reg)) {
433			error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
434			if (error != 0)
435				break;
436
437			map_regs_to_linux(&u.bsd_reg, &r.reg);
438			if (req == PTRACE_PEEKUSR) {
439				error = copyout((char *)&r.reg + uap->addr,
440				    (void *)uap->data, sizeof(l_int));
441				break;
442			}
443
444			*(l_int *)((char *)&r.reg + uap->addr) =
445			    (l_int)uap->data;
446
447			map_regs_from_linux(&u.bsd_reg, &r.reg);
448			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
449		}
450
451		/*
452		 * Simulate debug registers access
453		 */
454		if (uap->addr >= LINUX_DBREG_OFFSET &&
455		    uap->addr <= LINUX_DBREG_OFFSET + LINUX_DBREG_SIZE) {
456			error = kern_ptrace(td, PT_GETDBREGS, pid, &u.bsd_dbreg,
457			    0);
458			if (error != 0)
459				break;
460
461			uap->addr -= LINUX_DBREG_OFFSET;
462			if (req == PTRACE_PEEKUSR) {
463				error = copyout((char *)&u.bsd_dbreg +
464				    uap->addr, (void *)uap->data,
465				    sizeof(l_int));
466				break;
467			}
468
469			*(l_int *)((char *)&u.bsd_dbreg + uap->addr) =
470			     uap->data;
471			error = kern_ptrace(td, PT_SETDBREGS, pid,
472			    &u.bsd_dbreg, 0);
473		}
474
475		break;
476	}
477	case PTRACE_SYSCALL:
478		/* fall through */
479	default:
480		printf("linux: ptrace(%u, ...) not implemented\n",
481		    (unsigned int)uap->req);
482		error = EINVAL;
483		break;
484	}
485
486	return (error);
487}
488