| 1 | /* Shared utility routines for GDB to interact with agent. |
| 2 | |
| 3 | Copyright (C) 2009-2020 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, 0); |
| 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 | } |