1 files changed, 280 insertions, 0 deletions
diff --git a/gdbsupport/agent.cc b/gdbsupport/agent.cc
new file mode 100644
index 0000000..b4127ff
--- /dev/null
+++ b/gdbsupport/agent.cc
@@ -0,0 +1,280 @@
+/* Shared utility routines for GDB to interact with agent.
+
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "target/target.h"
+#include "gdbsupport/symbol.h"
+#include <unistd.h>
+#include "filestuff.h"
+
+#define IPA_SYM_STRUCT_NAME ipa_sym_addresses_common
+#include "agent.h"
+
+bool debug_agent = false;
+
+/* A stdarg wrapper for debug_vprintf.  */
+
+static void ATTRIBUTE_PRINTF (1, 2)
+debug_agent_printf (const char *fmt, ...)
+{
+  va_list ap;
+
+  if (!debug_agent)
+    return;
+  va_start (ap, fmt);
+  debug_vprintf (fmt, ap);
+  va_end (ap);
+}
+
+#define DEBUG_AGENT debug_agent_printf
+
+/* Global flag to determine using agent or not.  */
+bool use_agent = false;
+
+/* Addresses of in-process agent's symbols both GDB and GDBserver cares
+   about.  */
+
+struct ipa_sym_addresses_common
+{
+  CORE_ADDR addr_helper_thread_id;
+  CORE_ADDR addr_cmd_buf;
+  CORE_ADDR addr_capability;
+};
+
+/* Cache of the helper thread id.  FIXME: this global should be made
+   per-process.  */
+static uint32_t helper_thread_id = 0;
+
+static struct
+{
+  const char *name;
+  int offset;
+} symbol_list[] = {
+  IPA_SYM(helper_thread_id),
+  IPA_SYM(cmd_buf),
+  IPA_SYM(capability),
+};
+
+static struct ipa_sym_addresses_common ipa_sym_addrs;
+
+static bool all_agent_symbols_looked_up = false;
+
+bool
+agent_loaded_p (void)
+{
+  return all_agent_symbols_looked_up;
+}
+
+/* Look up all symbols needed by agent.  Return 0 if all the symbols are
+   found, return non-zero otherwise.  */
+
+int
+agent_look_up_symbols (void *arg)
+{
+  all_agent_symbols_looked_up = false;
+
+  for (int i = 0; i < sizeof (symbol_list) / sizeof (symbol_list[0]); i++)
+    {
+      CORE_ADDR *addrp =
+	(CORE_ADDR *) ((char *) &ipa_sym_addrs + symbol_list[i].offset);
+      struct objfile *objfile = (struct objfile *) arg;
+
+      if (find_minimal_symbol_address (symbol_list[i].name, addrp,
+				       objfile) != 0)
+	{
+	  DEBUG_AGENT ("symbol `%s' not found\n", symbol_list[i].name);
+	  return -1;
+	}
+    }
+
+  all_agent_symbols_looked_up = true;
+  return 0;
+}
+
+static unsigned int
+agent_get_helper_thread_id (void)
+{
+  if  (helper_thread_id == 0)
+    {
+      if (target_read_uint32 (ipa_sym_addrs.addr_helper_thread_id,
+			      &helper_thread_id))
+	warning (_("Error reading helper thread's id in lib"));
+    }
+
+  return helper_thread_id;
+}
+
+#ifdef HAVE_SYS_UN_H
+#include <sys/socket.h>
+#include <sys/un.h>
+#define SOCK_DIR P_tmpdir
+
+#ifndef UNIX_PATH_MAX
+#define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) NULL)->sun_path)
+#endif
+
+#endif
+
+/* Connects to synchronization socket.  PID is the pid of inferior, which is
+   used to set up the connection socket.  */
+
+static int
+gdb_connect_sync_socket (int pid)
+{
+#ifdef HAVE_SYS_UN_H
+  struct sockaddr_un addr;
+  int res, fd;
+  char path[UNIX_PATH_MAX];
+
+  res = xsnprintf (path, UNIX_PATH_MAX, "%s/gdb_ust%d", P_tmpdir, pid);
+  if (res >= UNIX_PATH_MAX)
+    return -1;
+
+  res = fd = gdb_socket_cloexec (PF_UNIX, SOCK_STREAM, 0);
+  if (res == -1)
+    {
+      warning (_("error opening sync socket: %s"), safe_strerror (errno));
+      return -1;
+    }
+
+  addr.sun_family = AF_UNIX;
+
+  res = xsnprintf (addr.sun_path, UNIX_PATH_MAX, "%s", path);
+  if (res >= UNIX_PATH_MAX)
+    {
+      warning (_("string overflow allocating socket name"));
+      close (fd);
+      return -1;
+    }
+
+  res = connect (fd, (struct sockaddr *) &addr, sizeof (addr));
+  if (res == -1)
+    {
+      warning (_("error connecting sync socket (%s): %s. "
+		 "Make sure the directory exists and that it is writable."),
+		 path, safe_strerror (errno));
+      close (fd);
+      return -1;
+    }
+
+  return fd;
+#else
+  return -1;
+#endif
+}
+
+/* Execute an agent command in the inferior.  PID is the value of pid of the
+   inferior.  CMD is the buffer for command.  GDB or GDBserver will store the
+   command into it and fetch the return result from CMD.  The interaction
+   between GDB/GDBserver and the agent is synchronized by a synchronization
+   socket.  Return zero if success, otherwise return non-zero.  */
+
+int
+agent_run_command (int pid, const char *cmd, int len)
+{
+  int fd;
+  int tid = agent_get_helper_thread_id ();
+  ptid_t ptid = ptid_t (pid, tid, 0);
+
+  int ret = target_write_memory (ipa_sym_addrs.addr_cmd_buf,
+				 (gdb_byte *) cmd, len);
+
+  if (ret != 0)
+    {
+      warning (_("unable to write"));
+      return -1;
+    }
+
+  DEBUG_AGENT ("agent: resumed helper thread\n");
+
+  /* Resume helper thread.  */
+  target_continue_no_signal (ptid);
+
+  fd = gdb_connect_sync_socket (pid);
+  if (fd >= 0)
+    {
+      char buf[1] = "";
+
+      DEBUG_AGENT ("agent: signalling helper thread\n");
+
+      do
+	{
+	  ret = write (fd, buf, 1);
+	} while (ret == -1 && errno == EINTR);
+
+	DEBUG_AGENT ("agent: waiting for helper thread's response\n");
+
+      do
+	{
+	  ret = read (fd, buf, 1);
+	} while (ret == -1 && errno == EINTR);
+
+      close (fd);
+
+      DEBUG_AGENT ("agent: helper thread's response received\n");
+    }
+  else
+    return -1;
+
+  /* Need to read response with the inferior stopped.  */
+  if (ptid != null_ptid)
+    {
+      /* Stop thread PTID.  */
+      DEBUG_AGENT ("agent: stop helper thread\n");
+      target_stop_and_wait (ptid);
+    }
+
+  if (fd >= 0)
+    {
+      if (target_read_memory (ipa_sym_addrs.addr_cmd_buf, (gdb_byte *) cmd,
+			      IPA_CMD_BUF_SIZE))
+	{
+	  warning (_("Error reading command response"));
+	  return -1;
+	}
+    }
+
+  return 0;
+}
+
+/* Each bit of it stands for a capability of agent.  */
+static uint32_t agent_capability = 0;
+
+/* Return true if agent has capability AGENT_CAP, otherwise return false.  */
+
+bool
+agent_capability_check (enum agent_capa agent_capa)
+{
+  if (agent_capability == 0)
+    {
+      if (target_read_uint32 (ipa_sym_addrs.addr_capability,
+			      &agent_capability))
+	warning (_("Error reading capability of agent"));
+    }
+  return (agent_capability & agent_capa) != 0;
+}
+
+/* Invalidate the cache of agent capability, so we'll read it from inferior
+   again.  Call it when launches a new program or reconnect to remote stub.  */
+
+void
+agent_capability_invalidate (void)
+{
+  agent_capability = 0;
+}