1 /* Shared utility routines for GDB to interact with agent. 2 3 Copyright (C) 2009-2013 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #ifdef GDBSERVER 21 #include "server.h" 22 #else 23 #include "defs.h" 24 #include "target.h" 25 #include "inferior.h" /* for non_stop */ 26 #endif 27 28 #include <string.h> 29 #include <unistd.h> 30 #include "agent.h" 31 32 int debug_agent = 0; 33 34 #ifdef GDBSERVER 35 #define DEBUG_AGENT(fmt, args...) \ 36 if (debug_agent) \ 37 fprintf (stderr, fmt, ##args); 38 #else 39 #define DEBUG_AGENT(fmt, args...) \ 40 if (debug_agent) \ 41 fprintf_unfiltered (gdb_stdlog, fmt, ##args); 42 #endif 43 44 /* Global flag to determine using agent or not. */ 45 int use_agent = 0; 46 47 /* Addresses of in-process agent's symbols both GDB and GDBserver cares 48 about. */ 49 50 struct ipa_sym_addresses 51 { 52 CORE_ADDR addr_helper_thread_id; 53 CORE_ADDR addr_cmd_buf; 54 CORE_ADDR addr_capability; 55 }; 56 57 /* Cache of the helper thread id. FIXME: this global should be made 58 per-process. */ 59 static unsigned int helper_thread_id = 0; 60 61 static struct 62 { 63 const char *name; 64 int offset; 65 int required; 66 } symbol_list[] = { 67 IPA_SYM(helper_thread_id), 68 IPA_SYM(cmd_buf), 69 IPA_SYM(capability), 70 }; 71 72 static struct ipa_sym_addresses ipa_sym_addrs; 73 74 static int all_agent_symbols_looked_up = 0; 75 76 int 77 agent_loaded_p (void) 78 { 79 return all_agent_symbols_looked_up; 80 } 81 82 /* Look up all symbols needed by agent. Return 0 if all the symbols are 83 found, return non-zero otherwise. */ 84 85 int 86 agent_look_up_symbols (void *arg) 87 { 88 int i; 89 90 all_agent_symbols_looked_up = 0; 91 92 for (i = 0; i < sizeof (symbol_list) / sizeof (symbol_list[0]); i++) 93 { 94 CORE_ADDR *addrp = 95 (CORE_ADDR *) ((char *) &ipa_sym_addrs + symbol_list[i].offset); 96 #ifdef GDBSERVER 97 98 if (look_up_one_symbol (symbol_list[i].name, addrp, 1) == 0) 99 #else 100 struct minimal_symbol *sym = 101 lookup_minimal_symbol (symbol_list[i].name, NULL, 102 (struct objfile *) arg); 103 104 if (sym != NULL) 105 *addrp = SYMBOL_VALUE_ADDRESS (sym); 106 else 107 #endif 108 { 109 DEBUG_AGENT ("symbol `%s' not found\n", symbol_list[i].name); 110 return -1; 111 } 112 } 113 114 all_agent_symbols_looked_up = 1; 115 return 0; 116 } 117 118 static unsigned int 119 agent_get_helper_thread_id (void) 120 { 121 if (helper_thread_id == 0) 122 { 123 #ifdef GDBSERVER 124 if (read_inferior_memory (ipa_sym_addrs.addr_helper_thread_id, 125 (unsigned char *) &helper_thread_id, 126 sizeof helper_thread_id)) 127 #else 128 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); 129 gdb_byte buf[4]; 130 131 if (target_read_memory (ipa_sym_addrs.addr_helper_thread_id, 132 buf, sizeof buf) == 0) 133 helper_thread_id = extract_unsigned_integer (buf, sizeof buf, 134 byte_order); 135 else 136 #endif 137 { 138 warning (_("Error reading helper thread's id in lib")); 139 } 140 } 141 142 return helper_thread_id; 143 } 144 145 #ifdef HAVE_SYS_UN_H 146 #include <sys/socket.h> 147 #include <sys/un.h> 148 #define SOCK_DIR P_tmpdir 149 150 #ifndef UNIX_PATH_MAX 151 #define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) NULL)->sun_path) 152 #endif 153 154 #endif 155 156 /* Connects to synchronization socket. PID is the pid of inferior, which is 157 used to set up the connection socket. */ 158 159 static int 160 gdb_connect_sync_socket (int pid) 161 { 162 #ifdef HAVE_SYS_UN_H 163 struct sockaddr_un addr; 164 int res, fd; 165 char path[UNIX_PATH_MAX]; 166 167 res = xsnprintf (path, UNIX_PATH_MAX, "%s/gdb_ust%d", P_tmpdir, pid); 168 if (res >= UNIX_PATH_MAX) 169 return -1; 170 171 res = fd = socket (PF_UNIX, SOCK_STREAM, 0); 172 if (res == -1) 173 { 174 warning (_("error opening sync socket: %s"), strerror (errno)); 175 return -1; 176 } 177 178 addr.sun_family = AF_UNIX; 179 180 res = xsnprintf (addr.sun_path, UNIX_PATH_MAX, "%s", path); 181 if (res >= UNIX_PATH_MAX) 182 { 183 warning (_("string overflow allocating socket name")); 184 close (fd); 185 return -1; 186 } 187 188 res = connect (fd, (struct sockaddr *) &addr, sizeof (addr)); 189 if (res == -1) 190 { 191 warning (_("error connecting sync socket (%s): %s. " 192 "Make sure the directory exists and that it is writable."), 193 path, strerror (errno)); 194 close (fd); 195 return -1; 196 } 197 198 return fd; 199 #else 200 return -1; 201 #endif 202 } 203 204 /* Execute an agent command in the inferior. PID is the value of pid of the 205 inferior. CMD is the buffer for command. GDB or GDBserver will store the 206 command into it and fetch the return result from CMD. The interaction 207 between GDB/GDBserver and the agent is synchronized by a synchronization 208 socket. Return zero if success, otherwise return non-zero. */ 209 210 int 211 agent_run_command (int pid, const char *cmd, int len) 212 { 213 int fd; 214 int tid = agent_get_helper_thread_id (); 215 ptid_t ptid = ptid_build (pid, tid, 0); 216 217 #ifdef GDBSERVER 218 int ret = write_inferior_memory (ipa_sym_addrs.addr_cmd_buf, 219 (const unsigned char *) cmd, len); 220 #else 221 int ret = target_write_memory (ipa_sym_addrs.addr_cmd_buf, cmd, len); 222 #endif 223 224 if (ret != 0) 225 { 226 warning (_("unable to write")); 227 return -1; 228 } 229 230 DEBUG_AGENT ("agent: resumed helper thread\n"); 231 232 /* Resume helper thread. */ 233 #ifdef GDBSERVER 234 { 235 struct thread_resume resume_info; 236 237 resume_info.thread = ptid; 238 resume_info.kind = resume_continue; 239 resume_info.sig = GDB_SIGNAL_0; 240 (*the_target->resume) (&resume_info, 1); 241 } 242 #else 243 target_resume (ptid, 0, GDB_SIGNAL_0); 244 #endif 245 246 fd = gdb_connect_sync_socket (pid); 247 if (fd >= 0) 248 { 249 char buf[1] = ""; 250 int ret; 251 252 DEBUG_AGENT ("agent: signalling helper thread\n"); 253 254 do 255 { 256 ret = write (fd, buf, 1); 257 } while (ret == -1 && errno == EINTR); 258 259 DEBUG_AGENT ("agent: waiting for helper thread's response\n"); 260 261 do 262 { 263 ret = read (fd, buf, 1); 264 } while (ret == -1 && errno == EINTR); 265 266 close (fd); 267 268 DEBUG_AGENT ("agent: helper thread's response received\n"); 269 } 270 else 271 return -1; 272 273 /* Need to read response with the inferior stopped. */ 274 if (!ptid_equal (ptid, null_ptid)) 275 { 276 struct target_waitstatus status; 277 int was_non_stop = non_stop; 278 /* Stop thread PTID. */ 279 DEBUG_AGENT ("agent: stop helper thread\n"); 280 #ifdef GDBSERVER 281 { 282 struct thread_resume resume_info; 283 284 resume_info.thread = ptid; 285 resume_info.kind = resume_stop; 286 resume_info.sig = GDB_SIGNAL_0; 287 (*the_target->resume) (&resume_info, 1); 288 } 289 290 non_stop = 1; 291 mywait (ptid, &status, 0, 0); 292 #else 293 non_stop = 1; 294 target_stop (ptid); 295 296 memset (&status, 0, sizeof (status)); 297 target_wait (ptid, &status, 0); 298 #endif 299 non_stop = was_non_stop; 300 } 301 302 if (fd >= 0) 303 { 304 #ifdef GDBSERVER 305 if (read_inferior_memory (ipa_sym_addrs.addr_cmd_buf, 306 (unsigned char *) cmd, IPA_CMD_BUF_SIZE)) 307 #else 308 if (target_read_memory (ipa_sym_addrs.addr_cmd_buf, (gdb_byte *) cmd, 309 IPA_CMD_BUF_SIZE)) 310 #endif 311 { 312 warning (_("Error reading command response")); 313 return -1; 314 } 315 } 316 317 return 0; 318 } 319 320 /* Each bit of it stands for a capability of agent. */ 321 static unsigned int agent_capability = 0; 322 323 /* Return true if agent has capability AGENT_CAP, otherwise return false. */ 324 325 int 326 agent_capability_check (enum agent_capa agent_capa) 327 { 328 if (agent_capability == 0) 329 { 330 #ifdef GDBSERVER 331 if (read_inferior_memory (ipa_sym_addrs.addr_capability, 332 (unsigned char *) &agent_capability, 333 sizeof agent_capability)) 334 #else 335 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); 336 gdb_byte buf[4]; 337 338 if (target_read_memory (ipa_sym_addrs.addr_capability, 339 buf, sizeof buf) == 0) 340 agent_capability = extract_unsigned_integer (buf, sizeof buf, 341 byte_order); 342 else 343 #endif 344 warning (_("Error reading capability of agent")); 345 } 346 return agent_capability & agent_capa; 347 } 348 349 /* Invalidate the cache of agent capability, so we'll read it from inferior 350 again. Call it when launches a new program or reconnect to remote stub. */ 351 352 void 353 agent_capability_invalidate (void) 354 { 355 agent_capability = 0; 356 } 357