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[binutils-gdb.git] / gdbsupport / agent.cc
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1 /* Shared utility routines for GDB to interact with agent.
3 Copyright (C) 2009-2022 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
20 #include "common-defs.h"
21 #include "target/target.h"
22 #include "gdbsupport/symbol.h"
23 #include <unistd.h>
24 #include "filestuff.h"
26 #define IPA_SYM_STRUCT_NAME ipa_sym_addresses_common
27 #include "agent.h"
29 bool debug_agent = false;
31 /* A stdarg wrapper for debug_vprintf. */
33 static void ATTRIBUTE_PRINTF (1, 2)
34 debug_agent_printf (const char *fmt, ...)
36 va_list ap;
38 if (!debug_agent)
39 return;
40 va_start (ap, fmt);
41 debug_vprintf (fmt, ap);
42 va_end (ap);
45 #define DEBUG_AGENT debug_agent_printf
47 /* Global flag to determine using agent or not. */
48 bool use_agent = false;
50 /* Addresses of in-process agent's symbols both GDB and GDBserver cares
51 about. */
53 struct ipa_sym_addresses_common
55 CORE_ADDR addr_helper_thread_id;
56 CORE_ADDR addr_cmd_buf;
57 CORE_ADDR addr_capability;
60 /* Cache of the helper thread id. FIXME: this global should be made
61 per-process. */
62 static uint32_t helper_thread_id = 0;
64 static struct
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),
74 static struct ipa_sym_addresses_common ipa_sym_addrs;
76 static bool all_agent_symbols_looked_up = false;
78 bool
79 agent_loaded_p (void)
81 return all_agent_symbols_looked_up;
84 /* Look up all symbols needed by agent. Return 0 if all the symbols are
85 found, return non-zero otherwise. */
87 int
88 agent_look_up_symbols (void *arg)
90 all_agent_symbols_looked_up = false;
92 for (int i = 0; i < sizeof (symbol_list) / sizeof (symbol_list[0]); i++)
94 CORE_ADDR *addrp =
95 (CORE_ADDR *) ((char *) &ipa_sym_addrs + symbol_list[i].offset);
96 struct objfile *objfile = (struct objfile *) arg;
98 if (find_minimal_symbol_address (symbol_list[i].name, addrp,
99 objfile) != 0)
101 DEBUG_AGENT ("symbol `%s' not found\n", symbol_list[i].name);
102 return -1;
106 all_agent_symbols_looked_up = true;
107 return 0;
110 static unsigned int
111 agent_get_helper_thread_id (void)
113 if (helper_thread_id == 0)
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"));
120 return helper_thread_id;
123 #ifdef HAVE_SYS_UN_H
124 #include <sys/socket.h>
125 #include <sys/un.h>
126 #define SOCK_DIR P_tmpdir
128 #ifndef UNIX_PATH_MAX
129 #define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) NULL)->sun_path)
130 #endif
132 #endif
134 /* Connects to synchronization socket. PID is the pid of inferior, which is
135 used to set up the connection socket. */
137 static int
138 gdb_connect_sync_socket (int pid)
140 #ifdef HAVE_SYS_UN_H
141 struct sockaddr_un addr = {};
142 int res, fd;
143 char path[UNIX_PATH_MAX];
145 res = xsnprintf (path, UNIX_PATH_MAX, "%s/gdb_ust%d", P_tmpdir, pid);
146 if (res >= UNIX_PATH_MAX)
147 return -1;
149 res = fd = gdb_socket_cloexec (PF_UNIX, SOCK_STREAM, 0);
150 if (res == -1)
152 warning (_("error opening sync socket: %s"), safe_strerror (errno));
153 return -1;
156 addr.sun_family = AF_UNIX;
158 res = xsnprintf (addr.sun_path, UNIX_PATH_MAX, "%s", path);
159 if (res >= UNIX_PATH_MAX)
161 warning (_("string overflow allocating socket name"));
162 close (fd);
163 return -1;
166 res = connect (fd, (struct sockaddr *) &addr, sizeof (addr));
167 if (res == -1)
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;
176 return fd;
177 #else
178 return -1;
179 #endif
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. */
189 agent_run_command (int pid, const char *cmd, int len)
191 int fd;
192 int tid = agent_get_helper_thread_id ();
193 ptid_t ptid = ptid_t (pid, tid);
195 int ret = target_write_memory (ipa_sym_addrs.addr_cmd_buf,
196 (gdb_byte *) cmd, len);
198 if (ret != 0)
200 warning (_("unable to write"));
201 return -1;
204 DEBUG_AGENT ("agent: resumed helper thread\n");
206 /* Resume helper thread. */
207 target_continue_no_signal (ptid);
209 fd = gdb_connect_sync_socket (pid);
210 if (fd >= 0)
212 char buf[1] = "";
214 DEBUG_AGENT ("agent: signalling helper thread\n");
218 ret = write (fd, buf, 1);
219 } while (ret == -1 && errno == EINTR);
221 DEBUG_AGENT ("agent: waiting for helper thread's response\n");
225 ret = read (fd, buf, 1);
226 } while (ret == -1 && errno == EINTR);
228 close (fd);
230 DEBUG_AGENT ("agent: helper thread's response received\n");
232 else
233 return -1;
235 /* Need to read response with the inferior stopped. */
236 if (ptid != null_ptid)
238 /* Stop thread PTID. */
239 DEBUG_AGENT ("agent: stop helper thread\n");
240 target_stop_and_wait (ptid);
243 if (fd >= 0)
245 if (target_read_memory (ipa_sym_addrs.addr_cmd_buf, (gdb_byte *) cmd,
246 IPA_CMD_BUF_SIZE))
248 warning (_("Error reading command response"));
249 return -1;
253 return 0;
256 /* Each bit of it stands for a capability of agent. */
257 static uint32_t agent_capability = 0;
259 /* Return true if agent has capability AGENT_CAP, otherwise return false. */
261 bool
262 agent_capability_check (enum agent_capa agent_capa)
264 if (agent_capability == 0)
266 if (target_read_uint32 (ipa_sym_addrs.addr_capability,
267 &agent_capability))
268 warning (_("Error reading capability of agent"));
270 return (agent_capability & agent_capa) != 0;
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. */
276 void
277 agent_capability_invalidate (void)
279 agent_capability = 0;