485 lines
13 KiB
C
485 lines
13 KiB
C
/* Target-vector operations for controlling Unix child processes, for GDB.
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Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
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Contributed by Cygnus Support.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "defs.h"
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#include "frame.h" /* required by inferior.h */
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#include "inferior.h"
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#include "target.h"
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#include "wait.h"
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#include "gdbcore.h"
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#include "ieee-float.h" /* Required by REGISTER_CONVERT_TO_XXX */
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#include "terminal.h" /* For #ifdef TIOCGPGRP and new_tty */
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#include <signal.h>
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#ifdef SET_STACK_LIMIT_HUGE
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#include <sys/time.h>
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#include <sys/resource.h>
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extern int original_stack_limit;
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#endif /* SET_STACK_LIMIT_HUGE */
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static void
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child_prepare_to_store PARAMS ((void));
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static int
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child_wait PARAMS ((int *));
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static void
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child_open PARAMS ((char *, int));
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static void
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child_files_info PARAMS ((struct target_ops *));
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static void
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child_detach PARAMS ((char *, int));
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static void
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child_attach PARAMS ((char *, int));
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static void
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child_create_inferior PARAMS ((char *, char *, char **));
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static void
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child_mourn_inferior PARAMS ((void));
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static int
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child_can_run PARAMS ((void));
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extern char **environ;
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/* Forward declaration */
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extern struct target_ops child_ops;
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/* Wait for child to do something. Return pid of child, or -1 in case
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of error; store status through argument pointer STATUS. */
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static int
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child_wait (status)
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int *status;
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{
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int pid;
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do {
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#ifdef USE_PROC_FS
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pid = proc_wait (status);
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#else
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pid = wait (status);
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#endif
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if (pid == -1) /* No more children to wait for */
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{
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fprintf (stderr, "Child process unexpectedly missing.\n");
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*status = 42; /* Claim it exited with signal 42 */
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return -1;
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}
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} while (pid != inferior_pid); /* Some other child died or stopped */
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return pid;
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}
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/* Attach to process PID, then initialize for debugging it. */
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static void
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child_attach (args, from_tty)
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char *args;
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int from_tty;
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{
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char *exec_file;
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int pid;
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if (!args)
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error_no_arg ("process-id to attach");
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#ifndef ATTACH_DETACH
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error ("Can't attach to a process on this machine.");
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#else
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pid = atoi (args);
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if (pid == getpid()) /* Trying to masturbate? */
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error ("I refuse to debug myself!");
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if (from_tty)
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{
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exec_file = (char *) get_exec_file (0);
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if (exec_file)
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printf ("Attaching program `%s', pid %d\n", exec_file, pid);
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else
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printf ("Attaching pid %d\n", pid);
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fflush (stdout);
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}
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attach (pid);
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inferior_pid = pid;
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push_target (&child_ops);
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#endif /* ATTACH_DETACH */
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}
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/* Take a program previously attached to and detaches it.
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The program resumes execution and will no longer stop
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on signals, etc. We'd better not have left any breakpoints
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in the program or it'll die when it hits one. For this
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to work, it may be necessary for the process to have been
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previously attached. It *might* work if the program was
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started via the normal ptrace (PTRACE_TRACEME). */
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static void
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child_detach (args, from_tty)
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char *args;
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int from_tty;
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{
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int siggnal = 0;
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#ifdef ATTACH_DETACH
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if (from_tty)
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{
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char *exec_file = get_exec_file (0);
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if (exec_file == 0)
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exec_file = "";
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printf ("Detaching program: %s pid %d\n",
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exec_file, inferior_pid);
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fflush (stdout);
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}
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if (args)
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siggnal = atoi (args);
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detach (siggnal);
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inferior_pid = 0;
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unpush_target (&child_ops); /* Pop out of handling an inferior */
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#else
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error ("This version of Unix does not support detaching a process.");
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#endif
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}
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/* Get ready to modify the registers array. On machines which store
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individual registers, this doesn't need to do anything. On machines
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which store all the registers in one fell swoop, this makes sure
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that registers contains all the registers from the program being
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debugged. */
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static void
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child_prepare_to_store ()
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{
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#ifdef CHILD_PREPARE_TO_STORE
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CHILD_PREPARE_TO_STORE ();
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#endif
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}
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/* Print status information about what we're accessing. */
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static void
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child_files_info (ignore)
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struct target_ops *ignore;
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{
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printf ("\tUsing the running image of %s process %d.\n",
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attach_flag? "attached": "child", inferior_pid);
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}
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/* ARGSUSED */
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static void
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child_open (arg, from_tty)
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char *arg;
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int from_tty;
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{
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error ("Use the \"run\" command to start a Unix child process.");
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}
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/* Start an inferior Unix child process and sets inferior_pid to its pid.
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EXEC_FILE is the file to run.
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ALLARGS is a string containing the arguments to the program.
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ENV is the environment vector to pass. Errors reported with error(). */
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#ifndef SHELL_FILE
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#define SHELL_FILE "/bin/sh"
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#endif
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static void
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child_create_inferior (exec_file, allargs, env)
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char *exec_file;
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char *allargs;
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char **env;
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{
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int pid;
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char *shell_command;
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char *shell_file;
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static char default_shell_file[] = SHELL_FILE;
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int len;
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int pending_execs;
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/* Set debug_fork then attach to the child while it sleeps, to debug. */
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static int debug_fork = 0;
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/* This is set to the result of setpgrp, which if vforked, will be visible
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to you in the parent process. It's only used by humans for debugging. */
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static int debug_setpgrp = 657473;
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char **save_our_env;
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/* If no exec file handed to us, get it from the exec-file command -- with
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a good, common error message if none is specified. */
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if (exec_file == 0)
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exec_file = get_exec_file(1);
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/* The user might want tilde-expansion, and in general probably wants
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the program to behave the same way as if run from
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his/her favorite shell. So we let the shell run it for us.
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FIXME, this should probably search the local environment (as
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modified by the setenv command), not the env gdb inherited. */
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shell_file = getenv ("SHELL");
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if (shell_file == NULL)
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shell_file = default_shell_file;
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len = 5 + strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 10;
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/* If desired, concat something onto the front of ALLARGS.
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SHELL_COMMAND is the result. */
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#ifdef SHELL_COMMAND_CONCAT
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shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len);
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strcpy (shell_command, SHELL_COMMAND_CONCAT);
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#else
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shell_command = (char *) alloca (len);
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shell_command[0] = '\0';
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#endif
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strcat (shell_command, "exec ");
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strcat (shell_command, exec_file);
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strcat (shell_command, " ");
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strcat (shell_command, allargs);
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/* exec is said to fail if the executable is open. */
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close_exec_file ();
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/* Retain a copy of our environment variables, since the child will
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replace the value of environ and if we're vforked, we have to
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restore it. */
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save_our_env = environ;
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/* Tell the terminal handling subsystem what tty we plan to run on;
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it will just record the information for later. */
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new_tty_prefork (inferior_io_terminal);
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/* It is generally good practice to flush any possible pending stdio
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output prior to doing a fork, to avoid the possibility of both the
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parent and child flushing the same data after the fork. */
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fflush (stdout);
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fflush (stderr);
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#if defined(USG) && !defined(HAVE_VFORK)
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pid = fork ();
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#else
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if (debug_fork)
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pid = fork ();
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else
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pid = vfork ();
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#endif
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if (pid < 0)
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perror_with_name ("vfork");
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if (pid == 0)
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{
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if (debug_fork)
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sleep (debug_fork);
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#ifdef TIOCGPGRP
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/* Run inferior in a separate process group. */
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#ifdef NEED_POSIX_SETPGID
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debug_setpgrp = setpgid (0, 0);
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#else
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#if defined(USG) && !defined(SETPGRP_ARGS)
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debug_setpgrp = setpgrp ();
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#else
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debug_setpgrp = setpgrp (getpid (), getpid ());
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#endif /* USG */
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#endif /* NEED_POSIX_SETPGID */
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if (debug_setpgrp == -1)
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perror("setpgrp failed in child");
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#endif /* TIOCGPGRP */
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#ifdef SET_STACK_LIMIT_HUGE
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/* Reset the stack limit back to what it was. */
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{
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struct rlimit rlim;
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getrlimit (RLIMIT_STACK, &rlim);
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rlim.rlim_cur = original_stack_limit;
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setrlimit (RLIMIT_STACK, &rlim);
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}
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#endif /* SET_STACK_LIMIT_HUGE */
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/* Ask the tty subsystem to switch to the one we specified earlier
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(or to share the current terminal, if none was specified). */
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new_tty ();
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/* Changing the signal handlers for the inferior after
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a vfork can also change them for the superior, so we don't mess
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with signals here. See comments in
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initialize_signals for how we get the right signal handlers
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for the inferior. */
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#ifdef USE_PROC_FS
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/* Use SVR4 /proc interface */
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proc_set_exec_trap ();
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#else
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/* "Trace me, Dr. Memory!" */
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call_ptrace (0, 0, (PTRACE_ARG3_TYPE) 0, 0);
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#endif
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/* There is no execlpe call, so we have to set the environment
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for our child in the global variable. If we've vforked, this
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clobbers the parent, but environ is restored a few lines down
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in the parent. By the way, yes we do need to look down the
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path to find $SHELL. Rich Pixley says so, and I agree. */
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environ = env;
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execlp (shell_file, shell_file, "-c", shell_command, (char *)0);
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fprintf (stderr, "Cannot exec %s: %s.\n", shell_file,
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safe_strerror (errno));
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fflush (stderr);
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_exit (0177);
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}
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/* Restore our environment in case a vforked child clob'd it. */
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environ = save_our_env;
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/* Now that we have a child process, make it our target. */
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push_target (&child_ops);
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#ifdef CREATE_INFERIOR_HOOK
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CREATE_INFERIOR_HOOK (pid);
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#endif
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/* The process was started by the fork that created it,
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but it will have stopped one instruction after execing the shell.
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Here we must get it up to actual execution of the real program. */
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inferior_pid = pid; /* Needed for wait_for_inferior stuff below */
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clear_proceed_status ();
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/* We will get a trace trap after one instruction.
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Continue it automatically. Eventually (after shell does an exec)
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it will get another trace trap. Then insert breakpoints and continue. */
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#ifdef START_INFERIOR_TRAPS_EXPECTED
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pending_execs = START_INFERIOR_TRAPS_EXPECTED;
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#else
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pending_execs = 2;
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#endif
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init_wait_for_inferior ();
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/* Set up the "saved terminal modes" of the inferior
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based on what modes we are starting it with. */
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target_terminal_init ();
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/* Install inferior's terminal modes. */
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target_terminal_inferior ();
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while (1)
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{
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stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */
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wait_for_inferior ();
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if (stop_signal != SIGTRAP)
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{
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/* Let shell child handle its own signals in its own way */
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/* FIXME, what if child has exit()ed? Must exit loop somehow */
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resume (0, stop_signal);
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}
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else
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{
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/* We handle SIGTRAP, however; it means child did an exec. */
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if (0 == --pending_execs)
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break;
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resume (0, 0); /* Just make it go on */
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}
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}
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stop_soon_quietly = 0;
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/* We are now in the child process of interest, having exec'd the
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correct program, and are poised at the first instruction of the
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new program. */
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#ifdef SOLIB_CREATE_INFERIOR_HOOK
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SOLIB_CREATE_INFERIOR_HOOK (pid);
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#endif
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/* Pedal to the metal. Away we go. */
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proceed ((CORE_ADDR) -1, 0, 0);
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}
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static void
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child_mourn_inferior ()
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{
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unpush_target (&child_ops);
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generic_mourn_inferior ();
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}
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static int
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child_can_run ()
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{
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return(1);
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}
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struct target_ops child_ops = {
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"child", /* to_shortname */
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"Unix child process", /* to_longname */
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"Unix child process (started by the \"run\" command).", /* to_doc */
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child_open, /* to_open */
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0, /* to_close */
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child_attach, /* to_attach */
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child_detach, /* to_detach */
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child_resume, /* to_resume */
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child_wait, /* to_wait */
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fetch_inferior_registers, /* to_fetch_registers */
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store_inferior_registers, /* to_store_registers */
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child_prepare_to_store, /* to_prepare_to_store */
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child_xfer_memory, /* to_xfer_memory */
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child_files_info, /* to_files_info */
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memory_insert_breakpoint, /* to_insert_breakpoint */
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memory_remove_breakpoint, /* to_remove_breakpoint */
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terminal_init_inferior, /* to_terminal_init */
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terminal_inferior, /* to_terminal_inferior */
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terminal_ours_for_output, /* to_terminal_ours_for_output */
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terminal_ours, /* to_terminal_ours */
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child_terminal_info, /* to_terminal_info */
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kill_inferior, /* to_kill */
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0, /* to_load */
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0, /* to_lookup_symbol */
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child_create_inferior, /* to_create_inferior */
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child_mourn_inferior, /* to_mourn_inferior */
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child_can_run, /* to_can_run */
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process_stratum, /* to_stratum */
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0, /* to_next */
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1, /* to_has_all_memory */
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1, /* to_has_memory */
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1, /* to_has_stack */
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1, /* to_has_registers */
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1, /* to_has_execution */
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0, /* sections */
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0, /* sections_end */
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OPS_MAGIC /* to_magic */
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};
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void
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_initialize_inftarg ()
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{
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add_target (&child_ops);
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}
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