1 /* $NetBSD: linux_ptrace.c,v 1.23 2021/09/07 11:43:04 riastradh 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
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.23 2021/09/07 11:43:04 riastradh Exp $");
35
36 #include <sys/param.h>
37 #include <sys/mount.h>
38 #include <sys/proc.h>
39 #include <sys/ptrace.h>
40 #include <sys/systm.h>
41 #include <sys/syscallargs.h>
42 #include <uvm/uvm_extern.h>
43
44 #include <machine/reg.h>
45 #include <machine/pcb.h>
46
47 #include <compat/linux/common/linux_types.h>
48 #include <compat/linux/common/linux_ptrace.h>
49 #include <compat/linux/common/linux_signal.h>
50
51 #include <compat/linux/common/linux_util.h>
52 #include <compat/linux/common/linux_machdep.h>
53 #include <compat/linux/common/linux_emuldata.h>
54 #include <compat/linux/common/linux_exec.h> /* for emul_linux */
55
56 #include <compat/linux/linux_syscallargs.h>
57
58 #include <lib/libkern/libkern.h> /* for offsetof() */
59
60 /*
61 * On ARMv2, uregs contains R0--R15, orig_R0.
62 * On ARMv3 and later, it's R0--R15, CPSR, orig_R0.
63 * As far as I can see, Linux doesn't initialise orig_R0 on ARMv2, so we
64 * just produce the ARMv3 version.
65 */
66
67 struct linux_reg {
68 long uregs[18];
69 };
70
71 #define LINUX_REG_R0 0
72 #define LINUX_REG_R1 1
73 #define LINUX_REG_R2 2
74 #define LINUX_REG_R3 3
75 #define LINUX_REG_R4 4
76 #define LINUX_REG_R5 5
77 #define LINUX_REG_R6 6
78 #define LINUX_REG_R7 7
79 #define LINUX_REG_R8 8
80 #define LINUX_REG_R9 9
81 #define LINUX_REG_R10 10
82 #define LINUX_REG_FP 11
83 #define LINUX_REG_IP 12
84 #define LINUX_REG_SP 13
85 #define LINUX_REG_LR 14
86 #define LINUX_REG_PC 15
87 #define LINUX_REG_CPSR 16
88 #define LINUX_REG_ORIG_R0 17
89
90 int linux_ptrace_disabled = 1; /* bitrotted */
91
92 int
linux_sys_ptrace_arch(struct lwp * l,const struct linux_sys_ptrace_args * uap,register_t * retval)93 linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
94 register_t *retval)
95 {
96 /* {
97 syscallarg(int) request;
98 syscallarg(int) pid;
99 syscallarg(int) addr;
100 syscallarg(int) data;
101 } */
102 struct proc *p = l->l_proc, *t;
103 struct lwp *lt;
104 #ifdef _ARM_ARCH_6
105 struct pcb *pcb;
106 void *val;
107 #endif
108 struct reg *regs = NULL;
109 struct linux_reg *linux_regs = NULL;
110 int request, error;
111
112 if (linux_ptrace_disabled)
113 return ENOSYS;
114
115 error = 0;
116 request = SCARG(uap, request);
117 regs = kmem_alloc(sizeof(struct reg), KM_SLEEP);
118 linux_regs = kmem_alloc(sizeof(struct linux_reg), KM_SLEEP);
119
120 switch (request) {
121 case LINUX_PTRACE_GETREGS:
122 break;
123 case LINUX_PTRACE_SETREGS:
124 error = copyin((void *)SCARG(uap, data), linux_regs,
125 sizeof(struct linux_reg));
126 if (error) {
127 goto out;
128 }
129 break;
130 default:
131 error = EIO;
132 goto out;
133 }
134
135 /* Find the process we are supposed to be operating on. */
136 mutex_enter(&proc_lock);
137 if ((t = proc_find(SCARG(uap, pid))) == NULL) {
138 mutex_exit(&proc_lock);
139 error = ESRCH;
140 goto out;
141 }
142 mutex_enter(t->p_lock);
143
144 /*
145 * You cannot do what you want to the process if:
146 * 1. It is not being traced at all,
147 */
148 if (!ISSET(t->p_slflag, PSL_TRACED)) {
149 mutex_exit(t->p_lock);
150 mutex_exit(&proc_lock);
151 error = EPERM;
152 goto out;
153 }
154 /*
155 * 2. It is being traced by procfs (which has different signal
156 * delivery semantics),
157 * 3. It is not being traced by _you_, or
158 * 4. It is not currently stopped.
159 */
160 if (t->p_pptr != p || t->p_stat != SSTOP || !t->p_waited) {
161 mutex_exit(t->p_lock);
162 mutex_exit(&proc_lock);
163 error = EBUSY;
164 goto out;
165 }
166 mutex_exit(&proc_lock);
167 /* XXX: ptrace needs revamp for multi-threading support. */
168 if (t->p_nlwps > 1) {
169 mutex_exit(t->p_lock);
170 error = ENOSYS;
171 goto out;
172 }
173 lt = LIST_FIRST(&t->p_lwps);
174 *retval = 0;
175
176 switch (request) {
177 case LINUX_PTRACE_GETREGS:
178 error = process_read_regs(lt, regs);
179 mutex_exit(t->p_lock);
180 if (error) {
181 break;
182 }
183 memset(linux_regs, 0, sizeof(*linux_regs));
184 memcpy(linux_regs->uregs, regs->r, 13 * sizeof(register_t));
185 linux_regs->uregs[LINUX_REG_SP] = regs->r_sp;
186 linux_regs->uregs[LINUX_REG_LR] = regs->r_lr;
187 linux_regs->uregs[LINUX_REG_PC] = regs->r_pc;
188 linux_regs->uregs[LINUX_REG_CPSR] = regs->r_cpsr;
189 linux_regs->uregs[LINUX_REG_ORIG_R0] = regs->r[0];
190
191 error = copyout(linux_regs, (void *)SCARG(uap, data),
192 sizeof(struct linux_reg));
193 break;
194
195 case LINUX_PTRACE_SETREGS:
196 memcpy(regs->r, linux_regs->uregs, 13 * sizeof(register_t));
197 regs->r_sp = linux_regs->uregs[LINUX_REG_SP];
198 regs->r_lr = linux_regs->uregs[LINUX_REG_LR];
199 regs->r_pc = linux_regs->uregs[LINUX_REG_PC];
200 regs->r_cpsr = linux_regs->uregs[LINUX_REG_CPSR];
201 error = process_write_regs(lt, regs);
202 mutex_exit(t->p_lock);
203 break;
204
205 #ifdef _ARM_ARCH_6
206 #define LINUX_PTRACE_GET_THREAD_AREA 22
207 case LINUX_PTRACE_GET_THREAD_AREA:
208 mutex_exit(t->p_lock);
209 pcb = lwp_getpcb(l);
210 val = (void *)pcb->pcb_user_pid_ro;
211 error = copyout(&val, (void *)SCARG(uap, data), sizeof(val));
212 break;
213 #endif
214
215 default:
216 mutex_exit(t->p_lock);
217 }
218 out:
219 if (regs)
220 kmem_free(regs, sizeof(*regs));
221 if (linux_regs)
222 kmem_free(linux_regs, sizeof(*linux_regs));
223 return error;
224
225 }
226