gdb/common/agent.c

   1 /* Shared utility routines for GDB to interact with agent.
   2
   3    Copyright (C) 2009-2014 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 "infrun.h"
  25 #include "objfiles.h"
  26 #endif
  27 #include "target/target.h"
  28 #include <unistd.h>
  29 #include "agent.h"
  30 #include "filestuff.h"
  31
  32 int debug_agent = 0;
  33
  34 /* A stdarg wrapper for debug_vprintf.  */
  35
  36 static void ATTRIBUTE_PRINTF (1, 2)
  37 debug_agent_printf (const char *fmt, ...)
  38 {
  39   va_list ap;
  40
  41   if (!debug_agent)
  42     return;
  43   va_start (ap, fmt);
  44   debug_vprintf (fmt, ap);
  45   va_end (ap);
  46 }
  47
  48 #define DEBUG_AGENT debug_agent_printf
  49
  50 /* Global flag to determine using agent or not.  */
  51 int use_agent = 0;
  52
  53 /* Addresses of in-process agent's symbols both GDB and GDBserver cares
  54    about.  */
  55
  56 struct ipa_sym_addresses
  57 {
  58   CORE_ADDR addr_helper_thread_id;
  59   CORE_ADDR addr_cmd_buf;
  60   CORE_ADDR addr_capability;
  61 };
  62
  63 /* Cache of the helper thread id.  FIXME: this global should be made
  64    per-process.  */
  65 static uint32_t helper_thread_id = 0;
  66
  67 static struct
  68 {
  69   const char *name;
  70   int offset;
  71   int required;
  72 } symbol_list[] = {
  73   IPA_SYM(helper_thread_id),
  74   IPA_SYM(cmd_buf),
  75   IPA_SYM(capability),
  76 };
  77
  78 static struct ipa_sym_addresses ipa_sym_addrs;
  79
  80 static int all_agent_symbols_looked_up = 0;
  81
  82 int
  83 agent_loaded_p (void)
  84 {
  85   return all_agent_symbols_looked_up;
  86 }
  87
  88 /* Look up all symbols needed by agent.  Return 0 if all the symbols are
  89    found, return non-zero otherwise.  */
  90
  91 int
  92 agent_look_up_symbols (void *arg)
  93 {
  94   int i;
  95
  96   all_agent_symbols_looked_up = 0;
  97
  98   for (i = 0; i < sizeof (symbol_list) / sizeof (symbol_list[0]); i++)
  99     {
 100       CORE_ADDR *addrp =
 101         (CORE_ADDR *) ((char *) &ipa_sym_addrs + symbol_list[i].offset);
 102 #ifdef GDBSERVER
 103
 104       if (look_up_one_symbol (symbol_list[i].name, addrp, 1) == 0)
 105 #else
 106       struct bound_minimal_symbol sym =
 107         lookup_minimal_symbol (symbol_list[i].name, NULL,
 108                                (struct objfile *) arg);
 109
 110       if (sym.minsym != NULL)
 111         *addrp = BMSYMBOL_VALUE_ADDRESS (sym);
 112       else
 113 #endif
 114         {
 115           DEBUG_AGENT ("symbol `%s' not found\n", symbol_list[i].name);
 116           return -1;
 117         }
 118     }
 119
 120   all_agent_symbols_looked_up = 1;
 121   return 0;
 122 }
 123
 124 static unsigned int
 125 agent_get_helper_thread_id (void)
 126 {
 127   if  (helper_thread_id == 0)
 128     {
 129       if (target_read_uint32 (ipa_sym_addrs.addr_helper_thread_id,
 130                               &helper_thread_id))
 131         warning (_("Error reading helper thread's id in lib"));
 132     }
 133
 134   return helper_thread_id;
 135 }
 136
 137 #ifdef HAVE_SYS_UN_H
 138 #include <sys/socket.h>
 139 #include <sys/un.h>
 140 #define SOCK_DIR P_tmpdir
 141
 142 #ifndef UNIX_PATH_MAX
 143 #define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) NULL)->sun_path)
 144 #endif
 145
 146 #endif
 147
 148 /* Connects to synchronization socket.  PID is the pid of inferior, which is
 149    used to set up the connection socket.  */
 150
 151 static int
 152 gdb_connect_sync_socket (int pid)
 153 {
 154 #ifdef HAVE_SYS_UN_H
 155   struct sockaddr_un addr;
 156   int res, fd;
 157   char path[UNIX_PATH_MAX];
 158
 159   res = xsnprintf (path, UNIX_PATH_MAX, "%s/gdb_ust%d", P_tmpdir, pid);
 160   if (res >= UNIX_PATH_MAX)
 161     return -1;
 162
 163   res = fd = gdb_socket_cloexec (PF_UNIX, SOCK_STREAM, 0);
 164   if (res == -1)
 165     {
 166       warning (_("error opening sync socket: %s"), strerror (errno));
 167       return -1;
 168     }
 169
 170   addr.sun_family = AF_UNIX;
 171
 172   res = xsnprintf (addr.sun_path, UNIX_PATH_MAX, "%s", path);
 173   if (res >= UNIX_PATH_MAX)
 174     {
 175       warning (_("string overflow allocating socket name"));
 176       close (fd);
 177       return -1;
 178     }
 179
 180   res = connect (fd, (struct sockaddr *) &addr, sizeof (addr));
 181   if (res == -1)
 182     {
 183       warning (_("error connecting sync socket (%s): %s. "
 184                  "Make sure the directory exists and that it is writable."),
 185                  path, strerror (errno));
 186       close (fd);
 187       return -1;
 188     }
 189
 190   return fd;
 191 #else
 192   return -1;
 193 #endif
 194 }
 195
 196 /* Execute an agent command in the inferior.  PID is the value of pid of the
 197    inferior.  CMD is the buffer for command.  GDB or GDBserver will store the
 198    command into it and fetch the return result from CMD.  The interaction
 199    between GDB/GDBserver and the agent is synchronized by a synchronization
 200    socket.  Return zero if success, otherwise return non-zero.  */
 201
 202 int
 203 agent_run_command (int pid, const char *cmd, int len)
 204 {
 205   int fd;
 206   int tid = agent_get_helper_thread_id ();
 207   ptid_t ptid = ptid_build (pid, tid, 0);
 208
 209   int ret = target_write_memory (ipa_sym_addrs.addr_cmd_buf,
 210                                  (gdb_byte *) cmd, len);
 211
 212   if (ret != 0)
 213     {
 214       warning (_("unable to write"));
 215       return -1;
 216     }
 217
 218   DEBUG_AGENT ("agent: resumed helper thread\n");
 219
 220   /* Resume helper thread.  */
 221 #ifdef GDBSERVER
 222 {
 223   struct thread_resume resume_info;
 224
 225   resume_info.thread = ptid;
 226   resume_info.kind = resume_continue;
 227   resume_info.sig = GDB_SIGNAL_0;
 228   (*the_target->resume) (&resume_info, 1);
 229 }
 230 #else
 231  target_resume (ptid, 0, GDB_SIGNAL_0);
 232 #endif
 233
 234   fd = gdb_connect_sync_socket (pid);
 235   if (fd >= 0)
 236     {
 237       char buf[1] = "";
 238       int ret;
 239
 240       DEBUG_AGENT ("agent: signalling helper thread\n");
 241
 242       do
 243         {
 244           ret = write (fd, buf, 1);
 245         } while (ret == -1 && errno == EINTR);
 246
 247         DEBUG_AGENT ("agent: waiting for helper thread's response\n");
 248
 249       do
 250         {
 251           ret = read (fd, buf, 1);
 252         } while (ret == -1 && errno == EINTR);
 253
 254       close (fd);
 255
 256       DEBUG_AGENT ("agent: helper thread's response received\n");
 257     }
 258   else
 259     return -1;
 260
 261   /* Need to read response with the inferior stopped.  */
 262   if (!ptid_equal (ptid, null_ptid))
 263     {
 264       struct target_waitstatus status;
 265       int was_non_stop = non_stop;
 266       /* Stop thread PTID.  */
 267       DEBUG_AGENT ("agent: stop helper thread\n");
 268 #ifdef GDBSERVER
 269       {
 270         struct thread_resume resume_info;
 271
 272         resume_info.thread = ptid;
 273         resume_info.kind = resume_stop;
 274         resume_info.sig = GDB_SIGNAL_0;
 275         (*the_target->resume) (&resume_info, 1);
 276       }
 277
 278       non_stop = 1;
 279       mywait (ptid, &status, 0, 0);
 280 #else
 281       non_stop = 1;
 282       target_stop (ptid);
 283
 284       memset (&status, 0, sizeof (status));
 285       target_wait (ptid, &status, 0);
 286 #endif
 287       non_stop = was_non_stop;
 288     }
 289
 290   if (fd >= 0)
 291     {
 292       if (target_read_memory (ipa_sym_addrs.addr_cmd_buf, (gdb_byte *) cmd,
 293                               IPA_CMD_BUF_SIZE))
 294         {
 295           warning (_("Error reading command response"));
 296           return -1;
 297         }
 298     }
 299
 300   return 0;
 301 }
 302
 303 /* Each bit of it stands for a capability of agent.  */
 304 static uint32_t agent_capability = 0;
 305
 306 /* Return true if agent has capability AGENT_CAP, otherwise return false.  */
 307
 308 int
 309 agent_capability_check (enum agent_capa agent_capa)
 310 {
 311   if (agent_capability == 0)
 312     {
 313       if (target_read_uint32 (ipa_sym_addrs.addr_capability,
 314                               &agent_capability))
 315         warning (_("Error reading capability of agent"));
 316     }
 317   return agent_capability & agent_capa;
 318 }
 319
 320 /* Invalidate the cache of agent capability, so we'll read it from inferior
 321    again.  Call it when launches a new program or reconnect to remote stub.  */
 322
 323 void
 324 agent_capability_invalidate (void)
 325 {
 326   agent_capability = 0;
 327 }