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
dump_memory(log_t * log,pid_t tid,uintptr_t addr,bool at_fault)45 static 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 */
dump_memory_and_code(const ptrace_context_t * context __attribute ((unused)),log_t * log,pid_t tid,bool at_fault)113 void 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, ®s)) {
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", ®_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
dump_registers(const ptrace_context_t * context __attribute ((unused)),log_t * log,pid_t tid,bool at_fault)149 void 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