1 /* $NetBSD: linux_ptrace.c,v 1.36 2022/09/05 14:14:42 tsutsui Exp $ */
2
3 /*-
4 * Copyright (c) 1999 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.
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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.36 2022/09/05 14:14:42 tsutsui Exp $");
34
35 #include <sys/param.h>
36 #include <sys/mount.h>
37 #include <sys/proc.h>
38 #include <sys/ptrace.h>
39 #include <sys/systm.h>
40 #include <sys/syscall.h>
41 #include <sys/syscallargs.h>
42 #include <uvm/uvm_extern.h>
43
44 #include <machine/reg.h>
45
46 #include <compat/linux/common/linux_types.h>
47 #include <compat/linux/common/linux_ptrace.h>
48 #include <compat/linux/common/linux_signal.h>
49
50 #include <compat/linux/common/linux_util.h>
51 #include <compat/linux/common/linux_machdep.h>
52 #include <compat/linux/common/linux_emuldata.h>
53 #include <compat/linux/common/linux_exec.h> /* for emul_linux */
54
55 #include <compat/linux/linux_syscallargs.h>
56
57 #include <lib/libkern/libkern.h> /* for offsetof() */
58
59 struct linux_reg {
60 long ebx;
61 long ecx;
62 long edx;
63 long esi;
64 long edi;
65 long ebp;
66 long eax;
67 long xds, xes; /* unsigned short ds, __ds, es, __es; */
68 long __fs, __gs; /* unsigned short fs, __fs, gs, __gs; */
69 long orig_eax;
70 long eip;
71 long xcs; /* unsigned short cs, __cs; */
72 long eflags;
73 long esp;
74 long xss; /* unsigned short ss, __ss; */
75 };
76
77 /* structure used for storing floating point context */
78 struct linux_fpctx {
79 long cwd;
80 long swd;
81 long twd;
82 long fip;
83 long fcs;
84 long foo;
85 long fos;
86 long st_space[20];
87 };
88
89 /* user struct for linux process - this is used for Linux ptrace emulation */
90 /* most of it is junk only used by gdb */
91 struct linux_user {
92 struct linux_reg regs; /* registers */
93 int u_fpvalid; /* true if math co-processor being used. */
94 struct linux_fpctx i387; /* Math Co-processor registers. */
95 /* The rest of this junk is to help gdb figure out what goes where */
96 #define lusr_startgdb u_tsize
97 unsigned long int u_tsize; /* Text segment size (pages). */
98 unsigned long int u_dsize; /* Data segment size (pages). */
99 unsigned long int u_ssize; /* Stack segment size (pages). */
100 unsigned long start_code; /* Starting virtual address of text. */
101 unsigned long start_stack; /* Starting virtual address of stack
102 area. This is actually the bottom of
103 the stack, the top of the stack is
104 always found in the esp register. */
105 long int __signal; /* Signal that caused the core dump. */
106 int __reserved; /* unused */
107 void *u_ar0; /* Used by gdb to help find the values
108 for the registers. */
109 struct linux_fpctx *u_fpstate; /* Math Co-processor pointer. */
110 unsigned long __magic; /* To uniquely identify a core file */
111 char u_comm[32]; /* User command that was responsible */
112 int u_debugreg[8];
113 #define u_debugreg_end u_debugreg[7]
114 };
115
116 #define LUSR_OFF(member) offsetof(struct linux_user, member)
117
118 int linux_ptrace_disabled = 1; /* bitrotted */
119
120 int
linux_sys_ptrace_arch(struct lwp * l,const struct linux_sys_ptrace_args * uap,register_t * retval)121 linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
122 register_t *retval)
123 {
124 /* {
125 syscallarg(int) request;
126 syscallarg(int) pid;
127 syscallarg(int) addr;
128 syscallarg(int) data;
129 } */
130 struct proc *p = l->l_proc, *t;
131 struct lwp *lt;
132 struct reg *regs = NULL;
133 struct fpreg *fpregs = NULL;
134 struct linux_reg *linux_regs = NULL;
135 struct linux_fpctx *linux_fpregs = NULL;
136 struct linux_emuldata *led;
137 int request, error, addr;
138 size_t fp_size;
139
140 if (linux_ptrace_disabled)
141 return ENOSYS;
142
143 error = 0;
144 request = SCARG(uap, request);
145
146 switch (request) {
147 case LINUX_PTRACE_PEEKUSR:
148 case LINUX_PTRACE_POKEUSR:
149 break;
150 case LINUX_PTRACE_GETREGS:
151 case LINUX_PTRACE_SETREGS:
152 regs = kmem_alloc(sizeof(struct reg), KM_SLEEP);
153 linux_regs = kmem_alloc(sizeof(struct linux_reg), KM_SLEEP);
154 if (request == LINUX_PTRACE_SETREGS) {
155 error = copyin((void *)SCARG(uap, data), linux_regs,
156 sizeof(struct linux_reg));
157 if (error) {
158 goto out;
159 }
160 }
161 break;
162 case LINUX_PTRACE_GETFPREGS:
163 case LINUX_PTRACE_SETFPREGS:
164 fpregs = kmem_alloc(sizeof(struct fpreg), KM_SLEEP);
165 linux_fpregs = kmem_alloc(sizeof(struct linux_fpctx), KM_SLEEP);
166 if (request == LINUX_PTRACE_SETFPREGS) {
167 error = copyin((void *)SCARG(uap, data), linux_fpregs,
168 sizeof(struct linux_fpctx));
169 if (error) {
170 goto out;
171 }
172 }
173 break;
174 default:
175 error = EIO;
176 goto out;
177 }
178
179 /* Find the process we are supposed to be operating on. */
180 mutex_enter(&proc_lock);
181 if ((t = proc_find(SCARG(uap, pid))) == NULL) {
182 mutex_exit(&proc_lock);
183 error = ESRCH;
184 goto out;
185 }
186 mutex_enter(t->p_lock);
187
188 /*
189 * You cannot do what you want to the process if:
190 * 1. It is not being traced at all,
191 */
192 if (!ISSET(t->p_slflag, PSL_TRACED)) {
193 mutex_exit(t->p_lock);
194 mutex_exit(&proc_lock);
195 error = EPERM;
196 goto out;
197 }
198 /*
199 * 2. It is not being traced by _you_, or
200 * 3. It is not currently stopped.
201 */
202 if (t->p_pptr != p || t->p_stat != SSTOP || !t->p_waited) {
203 mutex_exit(t->p_lock);
204 mutex_exit(&proc_lock);
205 error = EBUSY;
206 goto out;
207 }
208 mutex_exit(&proc_lock);
209 /* XXX: ptrace needs revamp for multi-threading support. */
210 if (t->p_nlwps > 1) {
211 mutex_exit(t->p_lock);
212 error = ENOSYS;
213 goto out;
214 }
215 lt = LIST_FIRST(&t->p_lwps);
216 *retval = 0;
217
218 switch (request) {
219 case LINUX_PTRACE_GETREGS:
220 error = process_read_regs(lt, regs);
221 mutex_exit(t->p_lock);
222 if (error) {
223 break;
224 }
225 memset(linux_regs, 0, sizeof(*linux_regs));
226 linux_regs->ebx = regs->r_ebx;
227 linux_regs->ecx = regs->r_ecx;
228 linux_regs->edx = regs->r_edx;
229 linux_regs->esi = regs->r_esi;
230 linux_regs->edi = regs->r_edi;
231 linux_regs->ebp = regs->r_ebp;
232 linux_regs->eax = regs->r_eax;
233 linux_regs->xds = regs->r_ds;
234 linux_regs->xes = regs->r_es;
235 linux_regs->orig_eax = regs->r_eax; /* XXX is this correct? */
236 linux_regs->eip = regs->r_cs + regs->r_eip;
237 linux_regs->xcs = regs->r_cs;
238 linux_regs->eflags = regs->r_eflags;
239 linux_regs->esp = regs->r_esp;
240 linux_regs->xss = regs->r_ss;
241
242 error = copyout(linux_regs, (void *)SCARG(uap, data),
243 sizeof(struct linux_reg));
244 break;
245
246 case LINUX_PTRACE_SETREGS:
247 regs->r_ebx = linux_regs->ebx;
248 regs->r_ecx = linux_regs->ecx;
249 regs->r_edx = linux_regs->edx;
250 regs->r_esi = linux_regs->esi;
251 regs->r_edi = linux_regs->edi;
252 regs->r_ebp = linux_regs->ebp;
253 regs->r_eax = linux_regs->eax;
254 regs->r_ds = linux_regs->xds;
255 regs->r_es = linux_regs->xes;
256 regs->r_eip = linux_regs->eip - linux_regs->xcs;
257 regs->r_cs = linux_regs->xcs;
258 regs->r_eflags = linux_regs->eflags;
259 regs->r_esp = linux_regs->esp;
260 regs->r_ss = linux_regs->xss;
261
262 error = process_write_regs(lt, regs);
263 mutex_exit(t->p_lock);
264 break;
265
266 case LINUX_PTRACE_GETFPREGS:
267 fp_size = sizeof fpregs;
268 error = process_read_fpregs(lt, fpregs, &fp_size);
269 mutex_exit(t->p_lock);
270 if (error) {
271 break;
272 }
273 /* Zero the contents if NetBSD fpreg structure is smaller */
274 if (fp_size < sizeof(struct linux_fpctx)) {
275 memset(linux_fpregs, '\0', sizeof(struct linux_fpctx));
276 }
277 memcpy(linux_fpregs, fpregs,
278 uimin(sizeof(struct linux_fpctx), fp_size));
279 error = copyout(linux_fpregs, (void *)SCARG(uap, data),
280 sizeof(struct linux_fpctx));
281 break;
282
283 case LINUX_PTRACE_SETFPREGS:
284 memset(fpregs, '\0', sizeof(struct fpreg));
285 memcpy(fpregs, linux_fpregs,
286 uimin(sizeof(struct linux_fpctx), sizeof(struct fpreg)));
287 error = process_write_regs(lt, regs);
288 mutex_exit(t->p_lock);
289 break;
290
291 case LINUX_PTRACE_PEEKUSR:
292 /* XXX locking */
293 addr = SCARG(uap, addr);
294
295 error = 0;
296 if (addr < LUSR_OFF(lusr_startgdb)) {
297 /* XXX should provide appropriate register */
298 error = ENOTSUP;
299 } else if (addr == LUSR_OFF(u_tsize))
300 *retval = p->p_vmspace->vm_tsize;
301 else if (addr == LUSR_OFF(u_dsize))
302 *retval = p->p_vmspace->vm_dsize;
303 else if (addr == LUSR_OFF(u_ssize))
304 *retval = p->p_vmspace->vm_ssize;
305 else if (addr == LUSR_OFF(start_code))
306 *retval = (register_t) p->p_vmspace->vm_taddr;
307 else if (addr == LUSR_OFF(start_stack))
308 *retval = (register_t) p->p_vmspace->vm_minsaddr;
309 else if (addr == LUSR_OFF(u_ar0))
310 *retval = LUSR_OFF(regs);
311 else if (addr >= LUSR_OFF(u_debugreg)
312 && addr <= LUSR_OFF(u_debugreg_end)) {
313 int off = (addr - LUSR_OFF(u_debugreg)) / sizeof(int);
314
315 /* only do this for Linux processes */
316 if (t->p_emul != &emul_linux) {
317 mutex_exit(t->p_lock);
318 return EINVAL;
319 }
320
321 led = lt->l_emuldata;
322 *retval = led->led_debugreg[off];
323 } else if (addr == LUSR_OFF(__signal)) {
324 error = ENOTSUP;
325 } else if (addr == LUSR_OFF(u_fpstate)) {
326 error = ENOTSUP;
327 } else if (addr == LUSR_OFF(__magic)) {
328 error = ENOTSUP;
329 } else if (addr == LUSR_OFF(u_comm)) {
330 error = ENOTSUP;
331 } else {
332 #ifdef DEBUG_LINUX
333 printf("linux_ptrace: unsupported address: %d\n", addr);
334 #endif
335 error = ENOTSUP;
336 }
337 mutex_exit(t->p_lock);
338 break;
339
340 case LINUX_PTRACE_POKEUSR:
341 /* we only support setting debugregs for now */
342 addr = SCARG(uap, addr);
343 if (addr >= LUSR_OFF(u_debugreg) &&
344 addr <= LUSR_OFF(u_debugreg_end)) {
345 int off = (addr - LUSR_OFF(u_debugreg)) / sizeof(int);
346 int data = SCARG(uap, data);
347
348 /* only do this for Linux processes */
349 if (t->p_emul != &emul_linux) {
350 mutex_exit(t->p_lock);
351 return EINVAL;
352 }
353 led = lt->l_emuldata;
354 led->led_debugreg[off] = data;
355 }
356 mutex_exit(t->p_lock);
357 break;
358
359 default:
360 mutex_exit(t->p_lock);
361 break;
362 }
363 out:
364 if (regs)
365 kmem_free(regs, sizeof(*regs));
366 if (linux_regs)
367 kmem_free(linux_regs, sizeof(*linux_regs));
368 if (fpregs)
369 kmem_free(fpregs, sizeof(*fpregs));
370 if (linux_fpregs)
371 kmem_free(linux_fpregs, sizeof(*linux_fpregs));
372
373 return error;
374 }
375