+/* Fork a Unix child process, and set up to debug it, for GDB.
+ Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
+ Contributed by Cygnus Support.
+
+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 2 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, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include "defs.h"
+#include "frame.h" /* required by inferior.h */
+#include "inferior.h"
+#include "target.h"
+#include "wait.h"
+#include "gdbcore.h"
+#include "terminal.h" /* For #ifdef TIOCGPGRP and new_tty */
+
+#include <signal.h>
+
+#ifdef SET_STACK_LIMIT_HUGE
+#include <sys/time.h>
+#include <sys/resource.h>
+
+extern int original_stack_limit;
+#endif /* SET_STACK_LIMIT_HUGE */
+
+extern char **environ;
+
+/* Start an inferior Unix child process and sets inferior_pid to its pid.
+ EXEC_FILE is the file to run.
+ ALLARGS is a string containing the arguments to the program.
+ ENV is the environment vector to pass. Errors reported with error(). */
+
+#ifndef SHELL_FILE
+#define SHELL_FILE "/bin/sh"
+#endif
+
+void
+fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun)
+ char *exec_file;
+ char *allargs;
+ char **env;
+ void (*traceme_fun) PARAMS ((void));
+ void (*init_trace_fun) PARAMS ((int));
+{
+ int pid;
+ char *shell_command;
+ char *shell_file;
+ static char default_shell_file[] = SHELL_FILE;
+ int len;
+ int pending_execs;
+ /* Set debug_fork then attach to the child while it sleeps, to debug. */
+ static int debug_fork = 0;
+ /* This is set to the result of setpgrp, which if vforked, will be visible
+ to you in the parent process. It's only used by humans for debugging. */
+ static int debug_setpgrp = 657473;
+ char **save_our_env;
+
+ /* If no exec file handed to us, get it from the exec-file command -- with
+ a good, common error message if none is specified. */
+ if (exec_file == 0)
+ exec_file = get_exec_file(1);
+
+ /* The user might want tilde-expansion, and in general probably wants
+ the program to behave the same way as if run from
+ his/her favorite shell. So we let the shell run it for us.
+ FIXME, this should probably search the local environment (as
+ modified by the setenv command), not the env gdb inherited. */
+ shell_file = getenv ("SHELL");
+ if (shell_file == NULL)
+ shell_file = default_shell_file;
+
+ len = 5 + strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 10;
+ /* If desired, concat something onto the front of ALLARGS.
+ SHELL_COMMAND is the result. */
+#ifdef SHELL_COMMAND_CONCAT
+ shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len);
+ strcpy (shell_command, SHELL_COMMAND_CONCAT);
+#else
+ shell_command = (char *) alloca (len);
+ shell_command[0] = '\0';
+#endif
+ strcat (shell_command, "exec ");
+ strcat (shell_command, exec_file);
+ strcat (shell_command, " ");
+ strcat (shell_command, allargs);
+
+ /* exec is said to fail if the executable is open. */
+ close_exec_file ();
+
+ /* Retain a copy of our environment variables, since the child will
+ replace the value of environ and if we're vforked, we have to
+ restore it. */
+ save_our_env = environ;
+
+ /* Tell the terminal handling subsystem what tty we plan to run on;
+ it will just record the information for later. */
+
+ new_tty_prefork (inferior_io_terminal);
+
+ /* It is generally good practice to flush any possible pending stdio
+ output prior to doing a fork, to avoid the possibility of both the
+ parent and child flushing the same data after the fork. */
+
+ fflush (stdout);
+ fflush (stderr);
+
+#if defined(USG) && !defined(HAVE_VFORK)
+ pid = fork ();
+#else
+ if (debug_fork)
+ pid = fork ();
+ else
+ pid = vfork ();
+#endif
+
+ if (pid < 0)
+ perror_with_name ("vfork");
+
+ if (pid == 0)
+ {
+ if (debug_fork)
+ sleep (debug_fork);
+
+#ifdef TIOCGPGRP
+ /* Run inferior in a separate process group. */
+#ifdef NEED_POSIX_SETPGID
+ debug_setpgrp = setpgid (0, 0);
+#else
+#if defined(USG) && !defined(SETPGRP_ARGS)
+ debug_setpgrp = setpgrp ();
+#else
+ debug_setpgrp = setpgrp (getpid (), getpid ());
+#endif /* USG */
+#endif /* NEED_POSIX_SETPGID */
+ if (debug_setpgrp == -1)
+ perror("setpgrp failed in child");
+#endif /* TIOCGPGRP */
+
+#ifdef SET_STACK_LIMIT_HUGE
+ /* Reset the stack limit back to what it was. */
+ {
+ struct rlimit rlim;
+
+ getrlimit (RLIMIT_STACK, &rlim);
+ rlim.rlim_cur = original_stack_limit;
+ setrlimit (RLIMIT_STACK, &rlim);
+ }
+#endif /* SET_STACK_LIMIT_HUGE */
+
+ /* Ask the tty subsystem to switch to the one we specified earlier
+ (or to share the current terminal, if none was specified). */
+
+ new_tty ();
+
+ /* Changing the signal handlers for the inferior after
+ a vfork can also change them for the superior, so we don't mess
+ with signals here. See comments in
+ initialize_signals for how we get the right signal handlers
+ for the inferior. */
+
+ /* "Trace me, Dr. Memory!" */
+ (*traceme_fun) ();
+
+ /* There is no execlpe call, so we have to set the environment
+ for our child in the global variable. If we've vforked, this
+ clobbers the parent, but environ is restored a few lines down
+ in the parent. By the way, yes we do need to look down the
+ path to find $SHELL. Rich Pixley says so, and I agree. */
+ environ = env;
+ execlp (shell_file, shell_file, "-c", shell_command, (char *)0);
+
+ fprintf (stderr, "Cannot exec %s: %s.\n", shell_file,
+ safe_strerror (errno));
+ fflush (stderr);
+ _exit (0177);
+ }
+
+ /* Restore our environment in case a vforked child clob'd it. */
+ environ = save_our_env;
+
+ /* Now that we have a child process, make it our target, and
+ initialize anything target-vector-specific that needs initializing. */
+ (*init_trace_fun)(pid);
+
+#ifdef CREATE_INFERIOR_HOOK
+ CREATE_INFERIOR_HOOK (pid);
+#endif
+
+/* The process was started by the fork that created it,
+ but it will have stopped one instruction after execing the shell.
+ Here we must get it up to actual execution of the real program. */
+
+ inferior_pid = pid; /* Needed for wait_for_inferior stuff below */
+
+ clear_proceed_status ();
+
+ /* We will get a trace trap after one instruction.
+ Continue it automatically. Eventually (after shell does an exec)
+ it will get another trace trap. Then insert breakpoints and continue. */
+
+#ifdef START_INFERIOR_TRAPS_EXPECTED
+ pending_execs = START_INFERIOR_TRAPS_EXPECTED;
+#else
+ pending_execs = 2;
+#endif
+
+ init_wait_for_inferior ();
+
+ /* Set up the "saved terminal modes" of the inferior
+ based on what modes we are starting it with. */
+ target_terminal_init ();
+
+ /* Install inferior's terminal modes. */
+ target_terminal_inferior ();
+
+ while (1)
+ {
+ stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */
+ wait_for_inferior ();
+ if (stop_signal != SIGTRAP)
+ {
+ /* Let shell child handle its own signals in its own way */
+ /* FIXME, what if child has exit()ed? Must exit loop somehow */
+ resume (0, stop_signal);
+ }
+ else
+ {
+ /* We handle SIGTRAP, however; it means child did an exec. */
+ if (0 == --pending_execs)
+ break;
+ resume (0, 0); /* Just make it go on */
+ }
+ }
+ stop_soon_quietly = 0;
+
+ /* We are now in the child process of interest, having exec'd the
+ correct program, and are poised at the first instruction of the
+ new program. */
+#ifdef SOLIB_CREATE_INFERIOR_HOOK
+ SOLIB_CREATE_INFERIOR_HOOK (pid);
+#endif
+}
projects / thirdparty / binutils-gdb.git / commitdiff
