linux_ptrace.c revision 113517 
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 * $FreeBSD: head/sys/i386/linux/linux_ptrace.c 113517 2003-04-15 16:29:39Z jhb $
29 */
30
31#include "opt_cpu.h"
32
33#include <sys/param.h>
34#include <sys/lock.h>
35#include <sys/mutex.h>
36#include <sys/proc.h>
37#include <sys/ptrace.h>
38#include <sys/syscallsubr.h>
39#include <sys/systm.h>
40
41#include <machine/md_var.h>
42#include <machine/pcb.h>
43#include <machine/reg.h>
44
45#include <i386/linux/linux.h>
46#include <i386/linux/linux_proto.h>
47
48#if !defined(CPU_ENABLE_SSE) && defined(I686_CPU)
49#define CPU_ENABLE_SSE
50#endif
51#if defined(CPU_DISABLE_SSE)
52#undef CPU_ENABLE_SSE
53#endif
54
55/*
56 *   Linux ptrace requests numbers. Mostly identical to FreeBSD,
57 *   except for MD ones and PT_ATTACH/PT_DETACH.
58 */
59#define	PTRACE_TRACEME		0
60#define	PTRACE_PEEKTEXT		1
61#define	PTRACE_PEEKDATA		2
62#define	PTRACE_PEEKUSR		3
63#define	PTRACE_POKETEXT		4
64#define	PTRACE_POKEDATA		5
65#define	PTRACE_POKEUSR		6
66#define	PTRACE_CONT		7
67#define	PTRACE_KILL		8
68#define	PTRACE_SINGLESTEP	9
69
70#define PTRACE_ATTACH		16
71#define PTRACE_DETACH		17
72
73#define	PTRACE_SYSCALL		24
74
75#define PTRACE_GETREGS		12
76#define PTRACE_SETREGS		13
77#define PTRACE_GETFPREGS	14
78#define PTRACE_SETFPREGS	15
79#define PTRACE_GETFPXREGS	18
80#define PTRACE_SETFPXREGS	19
81
82#define PTRACE_SETOPTIONS	21
83
84/*
85 * Linux keeps debug registers at the following
86 * offset in the user struct
87 */
88#define LINUX_DBREG_OFFSET	252
89#define LINUX_DBREG_SIZE	(8*sizeof(l_int))
90
91static __inline__ int
92map_signum(int signum)
93{
94
95	if (signum > 0 && signum <= LINUX_SIGTBLSZ)
96		signum = linux_to_bsd_signal[_SIG_IDX(signum)];
97	return ((signum == SIGSTOP)? 0 : signum);
98}
99
100struct linux_pt_reg {
101	l_long	ebx;
102	l_long	ecx;
103	l_long	edx;
104	l_long	esi;
105	l_long	edi;
106	l_long	ebp;
107	l_long	eax;
108	l_int	xds;
109	l_int	xes;
110	l_int	xfs;
111	l_int	xgs;
112	l_long	orig_eax;
113	l_long	eip;
114	l_int	xcs;
115	l_long	eflags;
116	l_long	esp;
117	l_int	xss;
118};
119
120/*
121 *   Translate i386 ptrace registers between Linux and FreeBSD formats.
122 *   The translation is pretty straighforward, for all registers, but
123 *   orig_eax on Linux side and r_trapno and r_err in FreeBSD
124 */
125static void
126map_regs_to_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
127{
128	linux_r->ebx = bsd_r->r_ebx;
129	linux_r->ecx = bsd_r->r_ecx;
130	linux_r->edx = bsd_r->r_edx;
131	linux_r->esi = bsd_r->r_esi;
132	linux_r->edi = bsd_r->r_edi;
133	linux_r->ebp = bsd_r->r_ebp;
134	linux_r->eax = bsd_r->r_eax;
135	linux_r->xds = bsd_r->r_ds;
136	linux_r->xes = bsd_r->r_es;
137	linux_r->xfs = bsd_r->r_fs;
138	linux_r->xgs = bsd_r->r_gs;
139	linux_r->orig_eax = bsd_r->r_eax;
140	linux_r->eip = bsd_r->r_eip;
141	linux_r->xcs = bsd_r->r_cs;
142	linux_r->eflags = bsd_r->r_eflags;
143	linux_r->esp = bsd_r->r_esp;
144	linux_r->xss = bsd_r->r_ss;
145}
146
147static void
148map_regs_from_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
149{
150	bsd_r->r_ebx = linux_r->ebx;
151	bsd_r->r_ecx = linux_r->ecx;
152	bsd_r->r_edx = linux_r->edx;
153	bsd_r->r_esi = linux_r->esi;
154	bsd_r->r_edi = linux_r->edi;
155	bsd_r->r_ebp = linux_r->ebp;
156	bsd_r->r_eax = linux_r->eax;
157	bsd_r->r_ds  = linux_r->xds;
158	bsd_r->r_es  = linux_r->xes;
159	bsd_r->r_fs  = linux_r->xfs;
160	bsd_r->r_gs  = linux_r->xgs;
161	bsd_r->r_eip = linux_r->eip;
162	bsd_r->r_cs  = linux_r->xcs;
163	bsd_r->r_eflags = linux_r->eflags;
164	bsd_r->r_esp = linux_r->esp;
165	bsd_r->r_ss = linux_r->xss;
166}
167
168struct linux_pt_fpreg {
169	l_long cwd;
170	l_long swd;
171	l_long twd;
172	l_long fip;
173	l_long fcs;
174	l_long foo;
175	l_long fos;
176	l_long st_space[2*10];
177};
178
179static void
180map_fpregs_to_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
181{
182	linux_r->cwd = bsd_r->fpr_env[0];
183	linux_r->swd = bsd_r->fpr_env[1];
184	linux_r->twd = bsd_r->fpr_env[2];
185	linux_r->fip = bsd_r->fpr_env[3];
186	linux_r->fcs = bsd_r->fpr_env[4];
187	linux_r->foo = bsd_r->fpr_env[5];
188	linux_r->fos = bsd_r->fpr_env[6];
189	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(linux_r->st_space));
190}
191
192static void
193map_fpregs_from_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
194{
195	bsd_r->fpr_env[0] = linux_r->cwd;
196	bsd_r->fpr_env[1] = linux_r->swd;
197	bsd_r->fpr_env[2] = linux_r->twd;
198	bsd_r->fpr_env[3] = linux_r->fip;
199	bsd_r->fpr_env[4] = linux_r->fcs;
200	bsd_r->fpr_env[5] = linux_r->foo;
201	bsd_r->fpr_env[6] = linux_r->fos;
202	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(bsd_r->fpr_acc));
203}
204
205struct linux_pt_fpxreg {
206	l_ushort	cwd;
207	l_ushort	swd;
208	l_ushort	twd;
209	l_ushort	fop;
210	l_long		fip;
211	l_long		fcs;
212	l_long		foo;
213	l_long		fos;
214	l_long		mxcsr;
215	l_long		reserved;
216	l_long		st_space[32];
217	l_long		xmm_space[32];
218	l_long		padding[56];
219};
220
221#ifdef CPU_ENABLE_SSE
222static int
223linux_proc_read_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
224{
225	int error;
226
227	error = 0;
228	mtx_lock_spin(&sched_lock);
229	if (cpu_fxsr == 0 || (td->td_proc->p_sflag & PS_INMEM) == 0)
230		error = EIO;
231	else
232		bcopy(&td->td_pcb->pcb_save.sv_xmm, fpxregs, sizeof(*fpxregs));
233	mtx_unlock_spin(&sched_lock);
234	return (error);
235}
236
237static int
238linux_proc_write_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
239{
240	int error;
241
242	error = 0;
243	mtx_lock_spin(&sched_lock);
244	if (cpu_fxsr == 0 || (td->td_proc->p_sflag & PS_INMEM) == 0)
245		error = EIO;
246	else
247		bcopy(fpxregs, &td->td_pcb->pcb_save.sv_xmm, sizeof(*fpxregs));
248	mtx_unlock_spin(&sched_lock);
249	return (error);
250}
251#endif
252
253int
254linux_ptrace(struct thread *td, struct linux_ptrace_args *uap)
255{
256	union {
257		struct linux_pt_reg	reg;
258		struct linux_pt_fpreg	fpreg;
259		struct linux_pt_fpxreg	fpxreg;
260	} r;
261	union {
262		struct reg		bsd_reg;
263		struct fpreg		bsd_fpreg;
264		struct dbreg		bsd_dbreg;
265	} u;
266	void *addr;
267	pid_t pid;
268	int error, req;
269
270	error = 0;
271
272	/* by default, just copy data intact */
273	req  = uap->req;
274	pid  = (pid_t)uap->pid;
275	addr = (void *)uap->addr;
276
277	switch (req) {
278	case PTRACE_TRACEME:
279	case PTRACE_POKETEXT:
280	case PTRACE_POKEDATA:
281	case PTRACE_KILL:
282		error = kern_ptrace(td, req, pid, addr, uap->data);
283		break;
284	case PTRACE_PEEKTEXT:
285	case PTRACE_PEEKDATA: {
286		/* need to preserve return value */
287		int rval = td->td_retval[0];
288		error = kern_ptrace(td, req, pid, addr, 0);
289		if (error == 0)
290			error = copyout(td->td_retval, (void *)uap->data,
291			    sizeof(l_int));
292		td->td_retval[0] = rval;
293		break;
294	}
295	case PTRACE_DETACH:
296		error = kern_ptrace(td, PT_DETACH, pid, (void *)1,
297		     map_signum(uap->data));
298		break;
299	case PTRACE_SINGLESTEP:
300	case PTRACE_CONT:
301		error = kern_ptrace(td, req, pid, (void *)1,
302		     map_signum(uap->data));
303		break;
304	case PTRACE_ATTACH:
305		error = kern_ptrace(td, PT_ATTACH, pid, addr, uap->data);
306		break;
307	case PTRACE_GETREGS:
308		/* Linux is using data where FreeBSD is using addr */
309		error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
310		if (error == 0) {
311			map_regs_to_linux(&u.bsd_reg, &r.reg);
312			error = copyout(&r.reg, (void *)uap->data,
313			    sizeof(r.reg));
314		}
315		break;
316	case PTRACE_SETREGS:
317		/* Linux is using data where FreeBSD is using addr */
318		error = copyin((void *)uap->data, &r.reg, sizeof(r.reg));
319		if (error == 0) {
320			map_regs_from_linux(&u.bsd_reg, &r.reg);
321			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
322		}
323		break;
324	case PTRACE_GETFPREGS:
325		/* Linux is using data where FreeBSD is using addr */
326		error = kern_ptrace(td, PT_GETFPREGS, pid, &u.bsd_fpreg, 0);
327		if (error == 0) {
328			map_fpregs_to_linux(&u.bsd_fpreg, &r.fpreg);
329			error = copyout(&r.fpreg, (void *)uap->data,
330			    sizeof(r.fpreg));
331		}
332		break;
333	case PTRACE_SETFPREGS:
334		/* Linux is using data where FreeBSD is using addr */
335		error = copyin((void *)uap->data, &r.fpreg, sizeof(r.fpreg));
336		if (error == 0) {
337			map_fpregs_from_linux(&u.bsd_fpreg, &r.fpreg);
338			error = kern_ptrace(td, PT_SETFPREGS, pid,
339			    &u.bsd_fpreg, 0);
340		}
341		break;
342	case PTRACE_SETFPXREGS:
343#ifdef CPU_ENABLE_SSE
344		error = copyin((void *)uap->data, &r.fpxreg, sizeof(r.fpxreg));
345		if (error)
346			break;
347#endif
348		/* FALL THROUGH */
349	case PTRACE_GETFPXREGS: {
350#ifdef CPU_ENABLE_SSE
351		struct proc *p;
352		struct thread *td2;
353
354		if (sizeof(struct linux_pt_fpxreg) != sizeof(struct savexmm)) {
355			static int once = 0;
356			if (!once) {
357				printf("linux: savexmm != linux_pt_fpxreg\n");
358				once = 1;
359			}
360			error = EIO;
361			break;
362		}
363
364		if ((p = pfind(uap->pid)) == NULL) {
365			error = ESRCH;
366			break;
367		}
368
369		if ((error = p_candebug(td, p)) != 0)
370			goto fail;
371
372		/* System processes can't be debugged. */
373		if ((p->p_flag & P_SYSTEM) != 0) {
374			error = EINVAL;
375			goto fail;
376		}
377
378		/* not being traced... */
379		if ((p->p_flag & P_TRACED) == 0) {
380			error = EPERM;
381			goto fail;
382		}
383
384		/* not being traced by YOU */
385		if (p->p_pptr != td->td_proc) {
386			error = EBUSY;
387			goto fail;
388		}
389
390		/* not currently stopped */
391		if (!P_SHOULDSTOP(p) || (p->p_flag & P_WAITED) == 0) {
392			error = EBUSY;
393			goto fail;
394		}
395
396		td2 = FIRST_THREAD_IN_PROC(p);
397		if (req == PTRACE_GETFPXREGS) {
398			_PHOLD(p);
399			error = linux_proc_read_fpxregs(td2, &r.fpxreg);
400			_PRELE(p);
401			PROC_UNLOCK(p);
402			if (error == 0)
403				error = copyout(&r.fpxreg, (void *)uap->data,
404				    sizeof(r.fpxreg));
405		} else {
406			/* clear dangerous bits exactly as Linux does*/
407			r.fpxreg.mxcsr &= 0xffbf;
408			_PHOLD(p);
409			error = linux_proc_write_fpxregs(td2, &r.fpxreg);
410			_PRELE(p);
411			PROC_UNLOCK(p);
412		}
413		break;
414
415	fail:
416		PROC_UNLOCK(p);
417#else
418		error = EIO;
419#endif
420		break;
421	}
422	case PTRACE_PEEKUSR:
423	case PTRACE_POKEUSR: {
424		error = EIO;
425
426		/* check addr for alignment */
427		if (uap->addr < 0 || uap->addr & (sizeof(l_int) - 1))
428			break;
429		/*
430		 * Allow linux programs to access register values in
431		 * user struct. We simulate this through PT_GET/SETREGS
432		 * as necessary.
433		 */
434		if (uap->addr < sizeof(struct linux_pt_reg)) {
435			error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
436			if (error != 0)
437				break;
438
439			map_regs_to_linux(&u.bsd_reg, &r.reg);
440			if (req == PTRACE_PEEKUSR) {
441				error = copyout((char *)&r.reg + uap->addr,
442				    (void *)uap->data, sizeof(l_int));
443				break;
444			}
445
446			*(l_int *)((char *)&r.reg + uap->addr) =
447			    (l_int)uap->data;
448
449			map_regs_from_linux(&u.bsd_reg, &r.reg);
450			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
451		}
452
453		/*
454		 * Simulate debug registers access
455		 */
456		if (uap->addr >= LINUX_DBREG_OFFSET &&
457		    uap->addr <= LINUX_DBREG_OFFSET + LINUX_DBREG_SIZE) {
458			error = kern_ptrace(td, PT_GETDBREGS, pid, &u.bsd_dbreg,
459			    0);
460			if (error != 0)
461				break;
462
463			uap->addr -= LINUX_DBREG_OFFSET;
464			if (req == PTRACE_PEEKUSR) {
465				error = copyout((char *)&u.bsd_dbreg +
466				    uap->addr, (void *)uap->data,
467				    sizeof(l_int));
468				break;
469			}
470
471			*(l_int *)((char *)&u.bsd_dbreg + uap->addr) =
472			     uap->data;
473			error = kern_ptrace(td, PT_SETDBREGS, pid,
474			    &u.bsd_dbreg, 0);
475		}
476
477		break;
478	}
479	case PTRACE_SYSCALL:
480		/* fall through */
481	default:
482		printf("linux: ptrace(%u, ...) not implemented\n",
483		    (unsigned int)uap->req);
484		error = EINVAL;
485		break;
486	}
487
488	return (error);
489}
490