Re: [RFA] Add new cmd line parameter "--pid" for attach.

[Michael Snyder <msnyder@redhat.com>]

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Elena Zannoni wrote:
> 
> Michael Snyder writes:
>  > Elena Zannoni wrote:
>  > >
>  > > Michael Snyder writes:
>  > >  >
>  > >  > Currently if you invoke gdb as:
>  > >  >
>  > >  >      gdb filename 12345
>  > >  >
>  > >  > gdb will attempt to open a corefile called "12345", and if that
>  > >  > fails it will print a "file not found" warning, and then attempt
>  > >  > to attach to a process "12345".
>  > >  >
>  > >  > There is a "--core <filename>" command-line argument,
>  > >  > so that you can specify a corefile without a symbol file:
>  > >  >
>  > >  >      gdb --core <filename>
>  > >  >
>  > >  > but there is no "--pid" option to allow you to specify
>  > >  > a process-id without a symbol file.
>  > >  >
>  > >  > This patch does two things:
>  > >  >
>  > >  > 1) Add a "--pid" option to allow specification of an attach pid.
>  > >  >
>  > >
>  > > This bit is approved.
>  > >
>  > >  > 2) If the second argument (after the symbol-file) begins with
>  > >  > a digit, try attach first instead of trying to open it as a
>  > >  > corefile first.  This eliminates the "file not found" warning.
>  > >  >
>  > >
>  > > About this, I have a question, what happens if you have a corefile
>  > > whose name starts with a digit? I tried it and I get an error:
>  > >
>  > > [ezannoni@localhost gdb]$ ./gdb -nw ./gdb 2222core
>  > > GNU gdb 2002-01-03-cvs
>  > > Copyright 2001 Free Software Foundation, Inc.
>  > > GDB is free software, covered by the GNU General Public License, and you are
>  > > welcome to change it and/or distribute copies of it under certain conditions.
>  > > Type "show copying" to see the conditions.
>  > > There is absolutely no warranty for GDB.  Type "show warranty" for details.
>  > > This GDB was configured as "i686-pc-linux-gnu"...
>  > > Attaching to program: /home/ezannoni/sources/native/gdb/gdb, process 2222
>  > > ptrace: No such process.
>  > >
>  > > then it proceeds normally to figure out it's a core file.
>  >
>  > Right -- this is actually the reverse of the old behavior
>  > (before my change).  Previously the algorythm was this:
>  >
>  >         Try to open a corefile
>  >         on failure, if isdigit(string[0])
>  >                 try to attach a pid.
>  >
>  > So if it was really a pid, you always got an error when
>  > it tried to open it as a corefile.  Now the algorythm is:
>  >
>  >         if isdigit (string[0])
>  >                 try to attach a pid
>  >                 on failure, try to open a corefile
>  >         else try to open a corefile
>  >
>  > So the only time you will get a failure warning is
>  > if you have a corefile whose name begins with a digit.
>  > I think that's an improvement (warning should be less
>  > frequent).
>  >
> 
> Yes, that's what I wanted to point out. We are swapping an error
> message with another. The advantage is that the warning shouldn't come
> up as often.  Can you commit this, adding the bit to the docs about
> specifying './2222core' instead of '2222core'?

OK, got it, doc change attached.
This is committed.

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2002-01-04  Michael Snyder  <msnyder@redhat.com>

	* main.c (captured_main): Add new command line option "--pid".
	If the second command line argument (following the symbol-file)
	begins with a digit, try to attach to it before trying to open
	it as a corefile.
	(print_gdb_help): Document the "--pid" argument.

2002-01-05  Michael Snyder  <msnyder@redhat.com>

	* gdb.texinfo (--pid): Document new command line option (attach).

Index: main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.14
diff -c -3 -p -r1.14 main.c
*** main.c	2001/11/22 00:23:12	1.14
--- main.c	2002/01/05 03:15:43
*************** captured_main (void *data)
*** 239,244 ****
--- 239,246 ----
        {"e", required_argument, 0, 'e'},
        {"core", required_argument, 0, 'c'},
        {"c", required_argument, 0, 'c'},
+       {"pid", required_argument, 0, 'p'},
+       {"p", required_argument, 0, 'p'},
        {"command", required_argument, 0, 'x'},
        {"version", no_argument, &print_version, 1},
        {"x", required_argument, 0, 'x'},
*************** captured_main (void *data)
*** 320,325 ****
--- 322,331 ----
  	  case 'c':
  	    corearg = optarg;
  	    break;
+ 	  case 'p':
+ 	    /* "corearg" is shared by "--core" and "--pid" */
+ 	    corearg = optarg;
+ 	    break;
  	  case 'x':
  	    cmdarg[ncmd++] = optarg;
  	    if (ncmd >= cmdsize)
*************** extern int gdbtk_test (char *);
*** 463,470 ****
  	      execarg = argv[optind];
  	      break;
  	    case 2:
! 	      /* FIXME: The documentation says this can be a
! 		 "ProcID". as well.  */
  	      corearg = argv[optind];
  	      break;
  	    case 3:
--- 469,476 ----
  	      execarg = argv[optind];
  	      break;
  	    case 2:
! 	      /* The documentation says this can be a "ProcID" as well. 
! 	         We will try it as both a corefile and a pid.  */
  	      corearg = argv[optind];
  	      break;
  	    case 3:
*************** extern int gdbtk_test (char *);
*** 586,597 ****
  
    if (corearg != NULL)
      {
!       if (catch_command_errors (core_file_command, corearg, !batch, RETURN_MASK_ALL) == 0)
  	{
! 	  /* See if the core file is really a PID. */
! 	  if (isdigit (corearg[0]))
! 	    catch_command_errors (attach_command, corearg, !batch, RETURN_MASK_ALL);
  	}
      }
  
    if (ttyarg != NULL)
--- 592,611 ----
  
    if (corearg != NULL)
      {
!       /* corearg may be either a corefile or a pid.
! 	 If its first character is a digit, try attach first
! 	 and then corefile.  Otherwise try corefile first. */
! 
!       if (isdigit (corearg[0]))
  	{
! 	  if (catch_command_errors (attach_command, corearg, 
! 				    !batch, RETURN_MASK_ALL) == 0)
! 	    catch_command_errors (core_file_command, corearg, 
! 				  !batch, RETURN_MASK_ALL);
  	}
+       else /* Can't be a pid, better be a corefile. */
+ 	catch_command_errors (core_file_command, corearg, 
+ 			      !batch, RETURN_MASK_ALL);
      }
  
    if (ttyarg != NULL)
*************** extern int gdbtk_test (char *);
*** 616,621 ****
--- 630,646 ----
  	catch_command_errors (source_command, gdbinit, 0, RETURN_MASK_ALL);
        }
  
+   /* These need to be set this late in the initialization to ensure that
+      they are defined for the current environment.  They define the
+      radix variables needed by a save-breakpoints file to preserve the
+      radix across the breakpoints restoration assuming they are restored
+      using the -x (-command) command line options.  */
+      
+   set_internalvar (lookup_internalvar ("input_radix"),
+ 		   value_from_longest (builtin_type_int, (LONGEST) input_radix));
+   set_internalvar (lookup_internalvar ("output_radix"),
+ 		   value_from_longest (builtin_type_int, (LONGEST) output_radix));
+ 
    for (i = 0; i < ncmd; i++)
      {
  #if 0
*************** Options:\n\n\
*** 752,757 ****
--- 777,783 ----
    --cd=DIR           Change current directory to DIR.\n\
    --command=FILE     Execute GDB commands from FILE.\n\
    --core=COREFILE    Analyze the core dump COREFILE.\n\
+   --pid=PID          Attach to running process PID.\n\
  ", stream);
    fputs_unfiltered ("\
    --dbx              DBX compatibility mode.\n\
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.68
diff -c -3 -p -r1.68 gdb.texinfo
*** gdb.texinfo	2002/01/07 09:28:43	1.68
--- gdb.texinfo	2002/01/10 23:01:46
*************** in sequential order.  The order makes a 
*** 891,901 ****
  When @value{GDBN} starts, it reads any arguments other than options as
  specifying an executable file and core file (or process ID).  This is
  the same as if the arguments were specified by the @samp{-se} and
! @samp{-c} options respectively.  (@value{GDBN} reads the first argument
! that does not have an associated option flag as equivalent to the
! @samp{-se} option followed by that argument; and the second argument
! that does not have an associated option flag, if any, as equivalent to
! the @samp{-c} option followed by that argument.)
  
  If @value{GDBN} has not been configured to included core file support,
  such as for most embedded targets, then it will complain about a second
--- 891,906 ----
  When @value{GDBN} starts, it reads any arguments other than options as
  specifying an executable file and core file (or process ID).  This is
  the same as if the arguments were specified by the @samp{-se} and
! @samp{-c} (or @samp{-p} options respectively.  (@value{GDBN} reads the
! first argument that does not have an associated option flag as
! equivalent to the @samp{-se} option followed by that argument; and the
! second argument that does not have an associated option flag, if any, as
! equivalent to the @samp{-c}/@samp{-p} option followed by that argument.)
! If the second argument begins with a decimal digit, @value{GDBN} will
! first attempt to attach to it as a process, and if that fails, attempt
! to open it as a corefile.  If you have a corefile whose name begins with
! a digit, you can prevent @value{GDBN} from treating it as a pid by 
! prefixing it with @samp{"./"}, eg. @samp{"./12345"}.
  
  If @value{GDBN} has not been configured to included core file support,
  such as for most embedded targets, then it will complain about a second
*************** file.
*** 934,945 ****
  @itemx -c @var{file}
  @cindex @code{--core}
  @cindex @code{-c}
! Use file @var{file} as a core dump to examine.
  
  @item -c @var{number}
! Connect to process ID @var{number}, as with the @code{attach} command
! (unless there is a file in core-dump format named @var{number}, in which
! case @samp{-c} specifies that file as a core dump to read).
  
  @item -command @var{file}
  @itemx -x @var{file}
--- 939,954 ----
  @itemx -c @var{file}
  @cindex @code{--core}
  @cindex @code{-c}
! Use file @var{file} as a core dump to examine.  
  
  @item -c @var{number}
! @item -pid @var{number}
! @itemx -p @var{number}
! @cindex @code{--pid}
! @cindex @code{-p}
! Connect to process ID @var{number}, as with the @code{attach} command.
! If there is no such process, @value{GDBN} will attempt to open a core
! file named @var{number}.
  
  @item -command @var{file}
  @itemx -x @var{file}