/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+ Copyright (C) 1990-2019 Free Software Foundation, Inc.
+
Contributed by Cygnus Support.
-This file is part of GDB.
+ 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 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 3 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.
+ 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. */
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
-#include <string.h>
-#include "frame.h" /* required by inferior.h */
#include "inferior.h"
-#include "target.h"
-#include "wait.h"
-#include "gdbcore.h"
+#include "gdbcmd.h"
#include "terminal.h"
-#include "thread.h"
+#include "gdbthread.h"
+#include "top.h"
+#include "gdbsupport/job-control.h"
+#include "gdbsupport/filestuff.h"
+#include "nat/fork-inferior.h"
+#include "gdbsupport/common-inferior.h"
+
+/* The exec-wrapper, if any, that will be used when starting the
+ inferior. */
-#include <signal.h>
+static char *exec_wrapper = NULL;
-extern char **environ;
+/* See gdbsupport/common-inferior.h. */
-#ifndef SHELL_FILE
-#define SHELL_FILE "/bin/sh"
-#endif
+const char *
+get_exec_wrapper ()
+{
+ return exec_wrapper;
+}
-/* 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. SHELL_FILE is the shell file,
- or NULL if we should pick one. Errors reported with error(). */
+/* See nat/fork-inferior.h. */
void
-fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun,
- shell_file)
- char *exec_file;
- char *allargs;
- char **env;
- void (*traceme_fun) PARAMS ((void));
- void (*init_trace_fun) PARAMS ((int));
- char *shell_file;
+gdb_flush_out_err ()
{
- int pid;
- char *shell_command;
- static char default_shell_file[] = SHELL_FILE;
- int len;
- /* 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-maybe, we might want a "set shell" command so the user can change
- the shell from within GDB (if so, change callers which pass in a non-NULL
- shell_file too). */
- if (shell_file == NULL)
- shell_file = getenv ("SHELL");
- if (shell_file == NULL)
- shell_file = default_shell_file;
-
- /* Multiplying the length of exec_file by 4 is to account for the fact
- that it may expand when quoted; it is a worst-case number based on
- every character being '. */
- len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 12;
- /* 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 ");
-
- /* Now add exec_file, quoting as necessary. */
- {
- char *p;
- int need_to_quote;
-
- /* Quoting in this style is said to work with all shells. But csh
- on IRIX 4.0.1 can't deal with it. So we only quote it if we need
- to. */
- p = exec_file;
- while (1)
- {
- switch (*p)
- {
- case '\'':
- case '"':
- case '(':
- case ')':
- case '$':
- case '&':
- case ';':
- case '<':
- case '>':
- case ' ':
- case '\n':
- case '\t':
- need_to_quote = 1;
- goto end_scan;
-
- case '\0':
- need_to_quote = 0;
- goto end_scan;
-
- default:
- break;
- }
- ++p;
- }
- end_scan:
- if (need_to_quote)
- {
- strcat (shell_command, "'");
- for (p = exec_file; *p != '\0'; ++p)
- {
- if (*p == '\'')
- strcat (shell_command, "'\\''");
- else
- strncat (shell_command, p, 1);
- }
- strcat (shell_command, "'");
- }
- else
- 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;
+ gdb_flush (main_ui->m_gdb_stdout);
+ gdb_flush (main_ui->m_gdb_stderr);
+}
+
+/* The ui structure that will be saved on 'prefork_hook' and
+ restored on 'postfork_hook'. */
+static struct ui *saved_ui = NULL;
+
+/* See nat/fork-inferior.h. */
+
+void
+prefork_hook (const char *args)
+{
+ const char *inferior_io_terminal = get_inferior_io_terminal ();
+
+ gdb_assert (saved_ui == NULL);
+ /* Retain a copy of our UI, since the child will replace this value
+ and if we're vforked, we have to restore it. */
+ saved_ui = current_ui;
/* 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. */
+/* See nat/fork-inferior.h. */
- gdb_flush (gdb_stdout);
- gdb_flush (gdb_stderr);
+void
+postfork_hook (pid_t pid)
+{
+ inferior *inf = current_inferior ();
-#if defined(USG) && !defined(HAVE_VFORK)
- pid = fork ();
-#else
- if (debug_fork)
- pid = fork ();
- else
- pid = vfork ();
-#endif
+ inferior_appeared (inf, pid);
- if (pid < 0)
- perror_with_name ("vfork");
+ /* Needed for wait_for_inferior stuff. */
+ inferior_ptid = ptid_t (pid);
- if (pid == 0)
- {
- if (debug_fork)
- sleep (debug_fork);
+ gdb_assert (saved_ui != NULL);
+ current_ui = saved_ui;
+ saved_ui = NULL;
- /* Run inferior in a separate process group. */
- debug_setpgrp = gdb_setpgid ();
- if (debug_setpgrp == -1)
- perror("setpgrp failed in child");
-
- /* 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_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file,
- safe_strerror (errno));
- gdb_flush (gdb_stderr);
- _exit (0177);
- }
+ new_tty_postfork ();
+}
- /* Restore our environment in case a vforked child clob'd it. */
- environ = save_our_env;
+/* See nat/fork-inferior.h. */
- init_thread_list();
+void
+postfork_child_hook ()
+{
+ /* 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;
- inferior_pid = pid; /* Needed for wait_for_inferior stuff below */
+ /* Make sure we switch to main_ui here in order to be able to
+ use the fprintf_unfiltered/warning/error functions. */
+ current_ui = main_ui;
- /* Now that we have a child process, make it our target, and
- initialize anything target-vector-specific that needs initializing. */
- (*init_trace_fun)(pid);
+ /* Create a new session for the inferior process, if necessary.
+ It will also place the inferior in a separate process group. */
+ if (create_tty_session () <= 0)
+ {
+ /* No session was created, but we still want to run the inferior
+ in a separate process group. */
+ debug_setpgrp = gdb_setpgid ();
+ if (debug_setpgrp == -1)
+ perror (_("setpgrp failed in child"));
+ }
- /* 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
+ /* Ask the tty subsystem to switch to the one we specified
+ earlier (or to share the current terminal, if none was
+ specified). */
+ new_tty ();
}
-/* Accept NTRAPS traps from the inferior. */
+/* See inferior.h. */
-void
-startup_inferior (ntraps)
- int ntraps;
+ptid_t
+gdb_startup_inferior (pid_t pid, int num_traps)
{
- int pending_execs = ntraps;
- int terminal_initted;
+ ptid_t ptid = startup_inferior (pid, num_traps, NULL, NULL);
- /* 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. */
+ /* Mark all threads non-executing. */
+ set_executing (ptid, 0);
- clear_proceed_status ();
+ return ptid;
+}
- init_wait_for_inferior ();
+/* Implement the "unset exec-wrapper" command. */
- terminal_initted = 0;
+static void
+unset_exec_wrapper_command (const char *args, int from_tty)
+{
+ xfree (exec_wrapper);
+ exec_wrapper = NULL;
+}
-#ifdef STARTUP_INFERIOR
- STARTUP_INFERIOR (pending_execs);
-#else
- while (1)
- {
- stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */
- wait_for_inferior ();
- if (stop_signal != TARGET_SIGNAL_TRAP)
- {
- /* 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 (!terminal_initted)
- {
- /* Now that the child has exec'd we know it has already set its
- process group. On POSIX systems, tcsetpgrp will fail with
- EPERM if we try it before the child's setpgid. */
-
- /* 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 ();
-
- terminal_initted = 1;
- }
- if (0 == --pending_execs)
- break;
- resume (0, TARGET_SIGNAL_0); /* Just make it go on */
- }
- }
-#endif /* STARTUP_INFERIOR */
- stop_soon_quietly = 0;
+static void
+show_startup_with_shell (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file,
+ _("Use of shell to start subprocesses is %s.\n"),
+ value);
+}
+
+void
+_initialize_fork_child (void)
+{
+ add_setshow_filename_cmd ("exec-wrapper", class_run, &exec_wrapper, _("\
+Set a wrapper for running programs.\n\
+The wrapper prepares the system and environment for the new program."),
+ _("\
+Show the wrapper for running programs."), NULL,
+ NULL, NULL,
+ &setlist, &showlist);
+
+ add_cmd ("exec-wrapper", class_run, unset_exec_wrapper_command,
+ _("Disable use of an execution wrapper."),
+ &unsetlist);
+
+ add_setshow_boolean_cmd ("startup-with-shell", class_support,
+ &startup_with_shell, _("\
+Set use of shell to start subprocesses. The default is on."), _("\
+Show use of shell to start subprocesses."), NULL,
+ NULL,
+ show_startup_with_shell,
+ &setlist, &showlist);
}
projects / deliverable / binutils-gdb.git / blobdiff