1/* system/debuggerd/debuggerd.c
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include <stddef.h>
19#include <stdbool.h>
20#include <stdlib.h>
21#include <string.h>
22#include <stdio.h>
23#include <errno.h>
24#include <sys/types.h>
25#include <sys/ptrace.h>
26
27#include <corkscrew/ptrace.h>
28
29#include <linux/user.h>
30
31#include "../utility.h"
32#include "../machine.h"
33
34/* enable to dump memory pointed to by every register */
35#define DUMP_MEMORY_FOR_ALL_REGISTERS 1
36
37#ifdef WITH_VFP
38#ifdef WITH_VFP_D32
39#define NUM_VFP_REGS 32
40#else
41#define NUM_VFP_REGS 16
42#endif
43#endif
44
45static void dump_memory(log_t* log, pid_t tid, uintptr_t addr, bool at_fault) {
46    char code_buffer[64];       /* actual 8+1+((8+1)*4) + 1 == 45 */
47    char ascii_buffer[32];      /* actual 16 + 1 == 17 */
48    uintptr_t p, end;
49
50    p = addr & ~3;
51    p -= 32;
52    if (p > addr) {
53        /* catch underflow */
54        p = 0;
55    }
56    /* Dump more memory content for the crashing thread. */
57    end = p + 256;
58    /* catch overflow; 'end - p' has to be multiples of 16 */
59    while (end < p)
60        end -= 16;
61
62    /* Dump the code around PC as:
63     *  addr     contents                             ascii
64     *  00008d34 ef000000 e8bd0090 e1b00000 512fff1e  ............../Q
65     *  00008d44 ea00b1f9 e92d0090 e3a070fc ef000000  ......-..p......
66     */
67    while (p < end) {
68        char* asc_out = ascii_buffer;
69
70        sprintf(code_buffer, "%08x ", p);
71
72        int i;
73        for (i = 0; i < 4; i++) {
74            /*
75             * If we see (data == -1 && errno != 0), we know that the ptrace
76             * call failed, probably because we're dumping memory in an
77             * unmapped or inaccessible page.  I don't know if there's
78             * value in making that explicit in the output -- it likely
79             * just complicates parsing and clarifies nothing for the
80             * enlightened reader.
81             */
82            long data = ptrace(PTRACE_PEEKTEXT, tid, (void*)p, NULL);
83            sprintf(code_buffer + strlen(code_buffer), "%08lx ", data);
84
85            /* Enable the following code blob to dump ASCII values */
86#if 0
87            int j;
88            for (j = 0; j < 4; j++) {
89                /*
90                 * Our isprint() allows high-ASCII characters that display
91                 * differently (often badly) in different viewers, so we
92                 * just use a simpler test.
93                 */
94                char val = (data >> (j*8)) & 0xff;
95                if (val >= 0x20 && val < 0x7f) {
96                    *asc_out++ = val;
97                } else {
98                    *asc_out++ = '.';
99                }
100            }
101#endif
102            p += 4;
103        }
104        *asc_out = '\0';
105        _LOG(log, !at_fault, "    %s %s\n", code_buffer, ascii_buffer);
106    }
107}
108
109/*
110 * If configured to do so, dump memory around *all* registers
111 * for the crashing thread.
112 */
113void dump_memory_and_code(const ptrace_context_t* context __attribute((unused)),
114        log_t* log, pid_t tid, bool at_fault) {
115    struct pt_regs regs;
116    if(ptrace(PTRACE_GETREGS, tid, 0, &regs)) {
117        return;
118    }
119
120    if (at_fault && DUMP_MEMORY_FOR_ALL_REGISTERS) {
121        static const char REG_NAMES[] = "r0r1r2r3r4r5r6r7r8r9slfpipsp";
122
123        for (int reg = 0; reg < 14; reg++) {
124            /* this may not be a valid way to access, but it'll do for now */
125            uintptr_t addr = regs.uregs[reg];
126
127            /*
128             * Don't bother if it looks like a small int or ~= null, or if
129             * it's in the kernel area.
130             */
131            if (addr < 4096 || addr >= 0xc0000000) {
132                continue;
133            }
134
135            _LOG(log, false, "\nmemory near %.2s:\n", &REG_NAMES[reg * 2]);
136            dump_memory(log, tid, addr, at_fault);
137        }
138    }
139
140    _LOG(log, !at_fault, "\ncode around pc:\n");
141    dump_memory(log, tid, (uintptr_t)regs.ARM_pc, at_fault);
142
143    if (regs.ARM_pc != regs.ARM_lr) {
144        _LOG(log, !at_fault, "\ncode around lr:\n");
145        dump_memory(log, tid, (uintptr_t)regs.ARM_lr, at_fault);
146    }
147}
148
149void dump_registers(const ptrace_context_t* context __attribute((unused)),
150        log_t* log, pid_t tid, bool at_fault)
151{
152    struct pt_regs r;
153    bool only_in_tombstone = !at_fault;
154
155    if(ptrace(PTRACE_GETREGS, tid, 0, &r)) {
156        _LOG(log, only_in_tombstone, "cannot get registers: %s\n", strerror(errno));
157        return;
158    }
159
160    _LOG(log, only_in_tombstone, "    r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
161            (uint32_t)r.ARM_r0, (uint32_t)r.ARM_r1, (uint32_t)r.ARM_r2, (uint32_t)r.ARM_r3);
162    _LOG(log, only_in_tombstone, "    r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
163            (uint32_t)r.ARM_r4, (uint32_t)r.ARM_r5, (uint32_t)r.ARM_r6, (uint32_t)r.ARM_r7);
164    _LOG(log, only_in_tombstone, "    r8 %08x  r9 %08x  sl %08x  fp %08x\n",
165            (uint32_t)r.ARM_r8, (uint32_t)r.ARM_r9, (uint32_t)r.ARM_r10, (uint32_t)r.ARM_fp);
166    _LOG(log, only_in_tombstone, "    ip %08x  sp %08x  lr %08x  pc %08x  cpsr %08x\n",
167            (uint32_t)r.ARM_ip, (uint32_t)r.ARM_sp, (uint32_t)r.ARM_lr,
168            (uint32_t)r.ARM_pc, (uint32_t)r.ARM_cpsr);
169
170#ifdef WITH_VFP
171    struct user_vfp vfp_regs;
172    int i;
173
174    if(ptrace(PTRACE_GETVFPREGS, tid, 0, &vfp_regs)) {
175        _LOG(log, only_in_tombstone, "cannot get registers: %s\n", strerror(errno));
176        return;
177    }
178
179    for (i = 0; i < NUM_VFP_REGS; i += 2) {
180        _LOG(log, only_in_tombstone, "    d%-2d %016llx  d%-2d %016llx\n",
181                i, vfp_regs.fpregs[i], i+1, vfp_regs.fpregs[i+1]);
182    }
183    _LOG(log, only_in_tombstone, "    scr %08lx\n", vfp_regs.fpscr);
184#endif
185}
186