How to implement gcore on pa-hpux ?

[Joel Brobecker <brobecker@adacore.com>]

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Hello,

I have implemented the gcore command on pa-hpux for one of our customers.
I would like to contribute this work, but I know that for sure the
approach is took is not acceptable.

The work is based on using the TT_PROC_CORE ttrace command:

      TT_PROC_CORE   This request causes the traced process to generate a
                     core file in the target process's current working
                     directory. The core file is named core.pid where pid is
                     the process ID of the target process. The process's
                     state is left unchanged.  The lwpid, addr, data and
                     addr2 arguments must be zero.

So I created a new function in infttrace.c. In order to avoid re-writing
the part of gcore.c that add the command, and handles the arguments of this
command, I simply hooked the new infttrace directly into the gcore code.
A bit crude, but it works and it's pretty localized.

For the FSF tree, I'd like to implement this a little better, and it
seems to me that the core part of this command, the part that actually
creates the core file, should be a method of some vector. But which
vector?

The way the gcore command is currently written, it seems that it would
make sense for it to be part of the target vector. No?

However, in the case of HP/UX, there is a slight complication, because
the method is only good in the native case...

Any suggestion?

Attached is the infttrace function that creates the core dump. It is
largely inspired from the HP WDB debugger sources (contributed recently).

Thanks,
-- 
Joel

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void
dump_core_file (int pid, const char *filename)
{
  int tt_status;
  char buf[64];

  tt_status = call_ttrace (TT_PROC_CORE, pid, (TTRACE_ARG_TYPE) filename, 0, 0);
  
  if (tt_status == -1)
    {
      /* With some versions of HP/UX, specifying the name of the core file
         is not supported, so this may have been the cause for this failure.
         Try again without the file name.  */
      tt_status = call_ttrace (TT_PROC_CORE, pid, 0, 0, 0);

      if (tt_status != -1)
        {
          /* Success, so indeed the filename was the source of the problem.
             Inform the user that the core file was named differently
             (if indeed the filename is different from the default core
             file name!)  */
          sprintf (buf, "core.%d", pid); 
          if (strcmp (filename, buf) != 0)
            {
              warning ("The Operating System does not allow the dump in %s",
                       filename);
              filename = buf;
            }
        }
    }
  
  if (tt_status == -1)
    perror_with_name ("ttrace:");
  else  
    fprintf_filtered (gdb_stdout, "Saved corefile %s\n", filename);

}