2002-01-17 Daniel Jacobowitz <drow@mvista.com>

        * low-hppabsd.c (myattach): New function, returning -1.
        * low-lynx.c (myattach): Likewise.
        * low-nbsd.c (myattach): Likewise.
        * low-sim.c (myattach): Likewise.
        * low-sparc.c (myattach): Likewise.
        * low-sun3.c (myattach): Likewise.

        * low-linux.c (myattach): New function.

        * server.c (attach_inferior): New function.
        (main): Handle "--attach".

8 files changed, 126 insertions, 9 deletions

diff --git a/gdb/gdbserver/low-hppabsd.c b/gdb/gdbserver/low-hppabsd.c
index 86f21ea..af2a0e6 100644
--- a/gdb/gdbserver/low-hppabsd.c
+++ b/gdb/gdbserver/low-hppabsd.c
@@ -81,6 +81,13 @@ kill_inferior (void)
 /*************inferior_died ();****VK**************/
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Return nonzero if the given thread is still alive.  */
 int
 mythread_alive (int pid)
diff --git a/gdb/gdbserver/low-linux.c b/gdb/gdbserver/low-linux.c
index 0fd14af..f2565d5 100644
--- a/gdb/gdbserver/low-linux.c
+++ b/gdb/gdbserver/low-linux.c
@@ -78,6 +78,23 @@ create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Attach to an inferior process.  */
+
+int
+myattach (int pid)
+{
+  if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
+    {
+      fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid,
+	       errno < sys_nerr ? sys_errlist[errno] : "unknown error",
+	       errno);
+      fflush (stderr);
+      _exit (0177);
+    }
+
+  return 0;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/low-lynx.c b/gdb/gdbserver/low-lynx.c
index e742207..0aee103 100644
--- a/gdb/gdbserver/low-lynx.c
+++ b/gdb/gdbserver/low-lynx.c
@@ -87,6 +87,13 @@ create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/low-nbsd.c b/gdb/gdbserver/low-nbsd.c
index b6897e7..188aca0 100644
--- a/gdb/gdbserver/low-nbsd.c
+++ b/gdb/gdbserver/low-nbsd.c
@@ -145,6 +145,13 @@ create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/low-sim.c b/gdb/gdbserver/low-sim.c
index 92407d0..39907e8 100644
--- a/gdb/gdbserver/low-sim.c
+++ b/gdb/gdbserver/low-sim.c
@@ -139,6 +139,13 @@ create_inferior (char *program, char **argv)
   return pid;
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/low-sparc.c b/gdb/gdbserver/low-sparc.c
index 7efaaeb..8b80e13 100644
--- a/gdb/gdbserver/low-sparc.c
+++ b/gdb/gdbserver/low-sparc.c
@@ -75,6 +75,13 @@ create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/low-sun3.c b/gdb/gdbserver/low-sun3.c
index 4269d57..a55f8a1 100644
--- a/gdb/gdbserver/low-sun3.c
+++ b/gdb/gdbserver/low-sun3.c
@@ -72,6 +72,13 @@ create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Attaching is not supported.  */
+int
+myattach (int pid)
+{
+  return -1;
+}
+
 /* Kill the inferior process.  Make us have no inferior.  */
 
 void
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index ab37b2e..5ed010b 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -39,6 +39,21 @@ start_inferior (char *argv[], char *statusptr)
   return mywait (statusptr);
 }
 
+static int
+attach_inferior (int pid, char *statusptr, unsigned char *sigptr)
+{
+  /* myattach should return -1 if attaching is unsupported,
+     0 if it succeeded, and call error() otherwise.  */
+  if (myattach (pid) != 0)
+    return -1;
+
+  inferior_pid = pid;
+
+  *sigptr = mywait (statusptr);
+
+  return 0;
+}
+
 extern int remote_debug;
 
 int
@@ -49,6 +64,10 @@ main (int argc, char *argv[])
   unsigned char signal;
   unsigned int len;
   CORE_ADDR mem_addr;
+  int bad_attach = 0;
+  int pid = 0;
+  int attached = 0;
+  char *arg_end;
 
   if (setjmp (toplevel))
     {
@@ -56,15 +75,44 @@ main (int argc, char *argv[])
       exit (1);
     }
 
-  if (argc < 3)
-    error ("Usage: gdbserver tty prog [args ...]");
+  if (argc >= 3 && strcmp (argv[2], "--attach") == 0)
+    {
+      if (argc == 4
+	  && argv[3] != '\0'
+	  && (pid = strtoul (argv[3], &arg_end, 10)) != 0
+	  && *arg_end == '\0')
+	{
+	  ;
+	}
+      else
+	bad_attach = 1;
+    }
+
+  if (argc < 3 || bad_attach)
+    error ("Usage:\tgdbserver tty prog [args ...]\n"
+		 "\tgdbserver tty --attach pid");
 
   initialize_low ();
 
-  /* Wait till we are at first instruction in program.  */
-  signal = start_inferior (&argv[2], &status);
+  if (pid == 0)
+    {
+      /* Wait till we are at first instruction in program.  */
+      signal = start_inferior (&argv[2], &status);
 
-  /* We are now stopped at the first instruction of the target process */
+      /* We are now stopped at the first instruction of the target process */
+    }
+  else
+    {
+      switch (attach_inferior (pid, &status, &signal))
+	{
+	case -1:
+	  error ("Attaching not supported on this target");
+	  break;
+	default:
+	  attached = 1;
+	  break;
+	}
+    }
 
   while (1)
     {
@@ -83,8 +131,18 @@ main (int argc, char *argv[])
 	      remote_debug = !remote_debug;
 	      break;
 	    case '!':
-	      extended_protocol = 1;
-	      prepare_resume_reply (own_buf, status, signal);
+	      if (attached == 0)
+		{
+		  extended_protocol = 1;
+		  prepare_resume_reply (own_buf, status, signal);
+		}
+	      else
+		{
+		  /* We can not use the extended protocol if we are
+		     attached, because we can not restart the running
+		     program.  So return unrecognized.  */
+		  own_buf[0] = '\0';
+		}
 	      break;
 	    case '?':
 	      prepare_resume_reply (own_buf, status, signal);
@@ -250,8 +308,8 @@ main (int argc, char *argv[])
 	}
       else
 	{
-	  fprintf (stderr, "Remote side has terminated connection.  GDBserver will reopen the connection.\n");
-
+	  fprintf (stderr, "Remote side has terminated connection.  "
+			   "GDBserver will reopen the connection.\n");
 	  remote_close ();
 	}
     }