1 /* Shared utility routines for GDB to interact with agent. 2 3 Copyright (C) 2009-2023 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 #include "common-defs.h" 21 #include "target/target.h" 22 #include "gdbsupport/symbol.h" 23 #include <unistd.h> 24 #include "filestuff.h" 25 26 #define IPA_SYM_STRUCT_NAME ipa_sym_addresses_common 27 #include "agent.h" 28 29 bool debug_agent = false; 30 31 /* A stdarg wrapper for debug_vprintf. */ 32 33 static void ATTRIBUTE_PRINTF (1, 2) 34 debug_agent_printf (const char *fmt, ...) 35 { 36 va_list ap; 37 38 if (!debug_agent) 39 return; 40 va_start (ap, fmt); 41 debug_vprintf (fmt, ap); 42 va_end (ap); 43 } 44 45 #define DEBUG_AGENT debug_agent_printf 46 47 /* Global flag to determine using agent or not. */ 48 bool use_agent = false; 49 50 /* Addresses of in-process agent's symbols both GDB and GDBserver cares 51 about. */ 52 53 struct ipa_sym_addresses_common 54 { 55 CORE_ADDR addr_helper_thread_id; 56 CORE_ADDR addr_cmd_buf; 57 CORE_ADDR addr_capability; 58 }; 59 60 /* Cache of the helper thread id. FIXME: this global should be made 61 per-process. */ 62 static uint32_t helper_thread_id = 0; 63 64 static struct 65 { 66 const char *name; 67 int offset; 68 } symbol_list[] = { 69 IPA_SYM(helper_thread_id), 70 IPA_SYM(cmd_buf), 71 IPA_SYM(capability), 72 }; 73 74 static struct ipa_sym_addresses_common ipa_sym_addrs; 75 76 static bool all_agent_symbols_looked_up = false; 77 78 bool 79 agent_loaded_p (void) 80 { 81 return all_agent_symbols_looked_up; 82 } 83 84 /* Look up all symbols needed by agent. Return 0 if all the symbols are 85 found, return non-zero otherwise. */ 86 87 int 88 agent_look_up_symbols (void *arg) 89 { 90 all_agent_symbols_looked_up = false; 91 92 for (int 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 struct objfile *objfile = (struct objfile *) arg; 97 98 if (find_minimal_symbol_address (symbol_list[i].name, addrp, 99 objfile) != 0) 100 { 101 DEBUG_AGENT ("symbol `%s' not found\n", symbol_list[i].name); 102 return -1; 103 } 104 } 105 106 all_agent_symbols_looked_up = true; 107 return 0; 108 } 109 110 static unsigned int 111 agent_get_helper_thread_id (void) 112 { 113 if (helper_thread_id == 0) 114 { 115 if (target_read_uint32 (ipa_sym_addrs.addr_helper_thread_id, 116 &helper_thread_id)) 117 warning (_("Error reading helper thread's id in lib")); 118 } 119 120 return helper_thread_id; 121 } 122 123 #ifdef HAVE_SYS_UN_H 124 #include <sys/socket.h> 125 #include <sys/un.h> 126 #define SOCK_DIR P_tmpdir 127 128 #ifndef UNIX_PATH_MAX 129 #define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) NULL)->sun_path) 130 #endif 131 132 #endif 133 134 /* Connects to synchronization socket. PID is the pid of inferior, which is 135 used to set up the connection socket. */ 136 137 static int 138 gdb_connect_sync_socket (int pid) 139 { 140 #ifdef HAVE_SYS_UN_H 141 struct sockaddr_un addr = {}; 142 int res, fd; 143 char path[UNIX_PATH_MAX]; 144 145 res = xsnprintf (path, UNIX_PATH_MAX, "%s/gdb_ust%d", P_tmpdir, pid); 146 if (res >= UNIX_PATH_MAX) 147 return -1; 148 149 res = fd = gdb_socket_cloexec (PF_UNIX, SOCK_STREAM, 0); 150 if (res == -1) 151 { 152 warning (_("error opening sync socket: %s"), safe_strerror (errno)); 153 return -1; 154 } 155 156 addr.sun_family = AF_UNIX; 157 158 res = xsnprintf (addr.sun_path, UNIX_PATH_MAX, "%s", path); 159 if (res >= UNIX_PATH_MAX) 160 { 161 warning (_("string overflow allocating socket name")); 162 close (fd); 163 return -1; 164 } 165 166 res = connect (fd, (struct sockaddr *) &addr, sizeof (addr)); 167 if (res == -1) 168 { 169 warning (_("error connecting sync socket (%s): %s. " 170 "Make sure the directory exists and that it is writable."), 171 path, safe_strerror (errno)); 172 close (fd); 173 return -1; 174 } 175 176 return fd; 177 #else 178 return -1; 179 #endif 180 } 181 182 /* Execute an agent command in the inferior. PID is the value of pid of the 183 inferior. CMD is the buffer for command. GDB or GDBserver will store the 184 command into it and fetch the return result from CMD. The interaction 185 between GDB/GDBserver and the agent is synchronized by a synchronization 186 socket. Return zero if success, otherwise return non-zero. */ 187 188 int 189 agent_run_command (int pid, const char *cmd, int len) 190 { 191 int fd; 192 int tid = agent_get_helper_thread_id (); 193 ptid_t ptid = ptid_t (pid, tid); 194 195 int ret = target_write_memory (ipa_sym_addrs.addr_cmd_buf, 196 (gdb_byte *) cmd, len); 197 198 if (ret != 0) 199 { 200 warning (_("unable to write")); 201 return -1; 202 } 203 204 DEBUG_AGENT ("agent: resumed helper thread\n"); 205 206 /* Resume helper thread. */ 207 target_continue_no_signal (ptid); 208 209 fd = gdb_connect_sync_socket (pid); 210 if (fd >= 0) 211 { 212 char buf[1] = ""; 213 214 DEBUG_AGENT ("agent: signalling helper thread\n"); 215 216 do 217 { 218 ret = write (fd, buf, 1); 219 } while (ret == -1 && errno == EINTR); 220 221 DEBUG_AGENT ("agent: waiting for helper thread's response\n"); 222 223 do 224 { 225 ret = read (fd, buf, 1); 226 } while (ret == -1 && errno == EINTR); 227 228 close (fd); 229 230 DEBUG_AGENT ("agent: helper thread's response received\n"); 231 } 232 else 233 return -1; 234 235 /* Need to read response with the inferior stopped. */ 236 if (ptid != null_ptid) 237 { 238 /* Stop thread PTID. */ 239 DEBUG_AGENT ("agent: stop helper thread\n"); 240 target_stop_and_wait (ptid); 241 } 242 243 if (fd >= 0) 244 { 245 if (target_read_memory (ipa_sym_addrs.addr_cmd_buf, (gdb_byte *) cmd, 246 IPA_CMD_BUF_SIZE)) 247 { 248 warning (_("Error reading command response")); 249 return -1; 250 } 251 } 252 253 return 0; 254 } 255 256 /* Each bit of it stands for a capability of agent. */ 257 static uint32_t agent_capability = 0; 258 259 /* Return true if agent has capability AGENT_CAP, otherwise return false. */ 260 261 bool 262 agent_capability_check (enum agent_capa agent_capa) 263 { 264 if (agent_capability == 0) 265 { 266 if (target_read_uint32 (ipa_sym_addrs.addr_capability, 267 &agent_capability)) 268 warning (_("Error reading capability of agent")); 269 } 270 return (agent_capability & agent_capa) != 0; 271 } 272 273 /* Invalidate the cache of agent capability, so we'll read it from inferior 274 again. Call it when launches a new program or reconnect to remote stub. */ 275 276 void 277 agent_capability_invalidate (void) 278 { 279 agent_capability = 0; 280 } 281