1 /* system/debuggerd/debuggerd.c 2 ** 3 ** Copyright 2012, 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 #define R(x) ((unsigned int)(x)) 38 39 static void dump_memory(log_t* log, pid_t tid, uintptr_t addr, int scopeFlags) { 40 char code_buffer[64]; /* actual 8+1+((8+1)*4) + 1 == 45 */ 41 char ascii_buffer[32]; /* actual 16 + 1 == 17 */ 42 uintptr_t p, end; 43 44 p = addr & ~3; 45 p -= 32; 46 if (p > addr) { 47 /* catch underflow */ 48 p = 0; 49 } 50 end = p + 80; 51 /* catch overflow; 'end - p' has to be multiples of 16 */ 52 while (end < p) 53 end -= 16; 54 55 /* Dump the code around PC as: 56 * addr contents ascii 57 * 00008d34 ef000000 e8bd0090 e1b00000 512fff1e ............../Q 58 * 00008d44 ea00b1f9 e92d0090 e3a070fc ef000000 ......-..p...... 59 */ 60 while (p < end) { 61 char* asc_out = ascii_buffer; 62 63 sprintf(code_buffer, "%08x ", p); 64 65 int i; 66 for (i = 0; i < 4; i++) { 67 /* 68 * If we see (data == -1 && errno != 0), we know that the ptrace 69 * call failed, probably because we're dumping memory in an 70 * unmapped or inaccessible page. I don't know if there's 71 * value in making that explicit in the output -- it likely 72 * just complicates parsing and clarifies nothing for the 73 * enlightened reader. 74 */ 75 long data = ptrace(PTRACE_PEEKTEXT, tid, (void*)p, NULL); 76 sprintf(code_buffer + strlen(code_buffer), "%08lx ", data); 77 78 int j; 79 for (j = 0; j < 4; j++) { 80 /* 81 * Our isprint() allows high-ASCII characters that display 82 * differently (often badly) in different viewers, so we 83 * just use a simpler test. 84 */ 85 char val = (data >> (j*8)) & 0xff; 86 if (val >= 0x20 && val < 0x7f) { 87 *asc_out++ = val; 88 } else { 89 *asc_out++ = '.'; 90 } 91 } 92 p += 4; 93 } 94 *asc_out = '\0'; 95 _LOG(log, scopeFlags, " %s %s\n", code_buffer, ascii_buffer); 96 } 97 } 98 99 /* 100 * If configured to do so, dump memory around *all* registers 101 * for the crashing thread. 102 */ 103 void dump_memory_and_code(const ptrace_context_t* context __attribute((unused)), 104 log_t* log, pid_t tid, bool at_fault) { 105 pt_regs_mips_t r; 106 if(ptrace(PTRACE_GETREGS, tid, 0, &r)) { 107 return; 108 } 109 110 int scopeFlags = at_fault ? SCOPE_AT_FAULT : 0; 111 if (at_fault && DUMP_MEMORY_FOR_ALL_REGISTERS) { 112 static const char REG_NAMES[] = "$0atv0v1a0a1a2a3t0t1t2t3t4t5t6t7s0s1s2s3s4s5s6s7t8t9k0k1gpsps8ra"; 113 114 for (int reg = 0; reg < 32; reg++) { 115 /* skip uninteresting registers */ 116 if (reg == 0 /* $0 */ 117 || reg == 26 /* $k0 */ 118 || reg == 27 /* $k1 */ 119 || reg == 31 /* $ra (done below) */ 120 ) 121 continue; 122 123 uintptr_t addr = R(r.regs[reg]); 124 125 /* 126 * Don't bother if it looks like a small int or ~= null, or if 127 * it's in the kernel area. 128 */ 129 if (addr < 4096 || addr >= 0x80000000) { 130 continue; 131 } 132 133 _LOG(log, scopeFlags | SCOPE_SENSITIVE, "\nmemory near %.2s:\n", ®_NAMES[reg * 2]); 134 dump_memory(log, tid, addr, scopeFlags | SCOPE_SENSITIVE); 135 } 136 } 137 138 unsigned int pc = R(r.cp0_epc); 139 unsigned int ra = R(r.regs[31]); 140 141 _LOG(log, scopeFlags, "\ncode around pc:\n"); 142 dump_memory(log, tid, (uintptr_t)pc, scopeFlags); 143 144 if (pc != ra) { 145 _LOG(log, scopeFlags, "\ncode around ra:\n"); 146 dump_memory(log, tid, (uintptr_t)ra, scopeFlags); 147 } 148 } 149 150 void dump_registers(const ptrace_context_t* context __attribute((unused)), 151 log_t* log, pid_t tid, bool at_fault) 152 { 153 pt_regs_mips_t r; 154 int scopeFlags = at_fault ? SCOPE_AT_FAULT : 0; 155 156 if(ptrace(PTRACE_GETREGS, tid, 0, &r)) { 157 _LOG(log, scopeFlags, "cannot get registers: %s\n", strerror(errno)); 158 return; 159 } 160 161 _LOG(log, scopeFlags, " zr %08x at %08x v0 %08x v1 %08x\n", 162 R(r.regs[0]), R(r.regs[1]), R(r.regs[2]), R(r.regs[3])); 163 _LOG(log, scopeFlags, " a0 %08x a1 %08x a2 %08x a3 %08x\n", 164 R(r.regs[4]), R(r.regs[5]), R(r.regs[6]), R(r.regs[7])); 165 _LOG(log, scopeFlags, " t0 %08x t1 %08x t2 %08x t3 %08x\n", 166 R(r.regs[8]), R(r.regs[9]), R(r.regs[10]), R(r.regs[11])); 167 _LOG(log, scopeFlags, " t4 %08x t5 %08x t6 %08x t7 %08x\n", 168 R(r.regs[12]), R(r.regs[13]), R(r.regs[14]), R(r.regs[15])); 169 _LOG(log, scopeFlags, " s0 %08x s1 %08x s2 %08x s3 %08x\n", 170 R(r.regs[16]), R(r.regs[17]), R(r.regs[18]), R(r.regs[19])); 171 _LOG(log, scopeFlags, " s4 %08x s5 %08x s6 %08x s7 %08x\n", 172 R(r.regs[20]), R(r.regs[21]), R(r.regs[22]), R(r.regs[23])); 173 _LOG(log, scopeFlags, " t8 %08x t9 %08x k0 %08x k1 %08x\n", 174 R(r.regs[24]), R(r.regs[25]), R(r.regs[26]), R(r.regs[27])); 175 _LOG(log, scopeFlags, " gp %08x sp %08x s8 %08x ra %08x\n", 176 R(r.regs[28]), R(r.regs[29]), R(r.regs[30]), R(r.regs[31])); 177 _LOG(log, scopeFlags, " hi %08x lo %08x bva %08x epc %08x\n", 178 R(r.hi), R(r.lo), R(r.cp0_badvaddr), R(r.cp0_epc)); 179 } 180
