/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
- 2001, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 1990-2017 Free Software Foundation, Inc.
Contributed by Cygnus Support.
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
+ 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,
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., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
-#include "gdb_string.h"
-#include "frame.h" /* required by inferior.h */
#include "inferior.h"
+#include "terminal.h"
#include "target.h"
#include "gdb_wait.h"
#include "gdb_vfork.h"
#include "gdbcore.h"
-#include "terminal.h"
#include "gdbthread.h"
#include "command.h" /* for dont_repeat () */
+#include "gdbcmd.h"
#include "solib.h"
-
+#include "filestuff.h"
+#include "top.h"
+#include "signals-state-save-restore.h"
#include <signal.h>
+#include <vector>
/* This just gets used as a default if we can't find SHELL. */
-#ifndef SHELL_FILE
#define SHELL_FILE "/bin/sh"
-#endif
extern char **environ;
+static char *exec_wrapper;
+
/* Break up SCRATCH into an argument vector suitable for passing to
execvp and store it in ARGV. E.g., on "run a b c d" this routine
would get as input the string "a b c d", and as output it would
fill in ARGV with the four arguments "a", "b", "c", "d". */
static void
-breakup_args (char *scratch, char **argv)
+breakup_args (const std::string &scratch, std::vector<char *> &argv)
{
- char *cp = scratch;
-
- for (;;)
+ for (size_t cur_pos = 0; cur_pos < scratch.size ();)
{
- /* Scan past leading separators */
- while (*cp == ' ' || *cp == '\t' || *cp == '\n')
- cp++;
-
- /* Break if at end of string. */
- if (*cp == '\0')
- break;
-
- /* Take an arg. */
- *argv++ = cp;
-
- /* Scan for next arg separator. */
- cp = strchr (cp, ' ');
- if (cp == NULL)
- cp = strchr (cp, '\t');
- if (cp == NULL)
- cp = strchr (cp, '\n');
-
- /* No separators => end of string => break. */
- if (cp == NULL)
- break;
-
- /* Replace the separator with a terminator. */
- *cp++ = '\0';
+ /* Skip whitespace-like chars. */
+ std::size_t pos = scratch.find_first_not_of (" \t\n", cur_pos);
+
+ if (pos != std::string::npos)
+ cur_pos = pos;
+
+ /* Find the position of the next separator. */
+ std::size_t next_sep = scratch.find_first_of (" \t\n", cur_pos);
+
+ /* No separator found, which means this is the last
+ argument. */
+ if (next_sep == std::string::npos)
+ next_sep = scratch.size ();
+
+ char *arg = savestring (scratch.c_str () + cur_pos, next_sep - cur_pos);
+ argv.push_back (arg);
+
+ cur_pos = next_sep;
}
- /* Null-terminate the vector. */
- *argv = NULL;
+ /* NULL-terminate the vector. */
+ argv.push_back (NULL);
}
/* When executing a command under the given shell, return non-zero if
return 0;
}
+/* See inferior.h. */
+
+void
+trace_start_error (const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start (ap, fmt);
+ fprintf_unfiltered (gdb_stderr, "Could not trace the inferior "
+ "process.\nError: ");
+ vfprintf_unfiltered (gdb_stderr, fmt, ap);
+ va_end (ap);
+
+ gdb_flush (gdb_stderr);
+ _exit (0177);
+}
+
+/* See inferior.h. */
+
+void
+trace_start_error_with_name (const char *string)
+{
+ trace_start_error ("%s: %s", string, safe_strerror (errno));
+}
+
/* Start an inferior Unix child process and sets inferior_ptid 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. EXEC_FUN is the exec(2) function to use, or NULL for the default
one. */
/* This function is NOT reentrant. Some of the variables have been
made static to ensure that they survive the vfork call. */
-void
-fork_inferior (char *exec_file_arg, char *allargs, char **env,
- void (*traceme_fun) (void), void (*init_trace_fun) (int),
- void (*pre_trace_fun) (void), char *shell_file_arg)
+int
+fork_inferior (const char *exec_file_arg, const std::string &allargs,
+ char **env, void (*traceme_fun) (void),
+ void (*init_trace_fun) (int), void (*pre_trace_fun) (void),
+ char *shell_file_arg,
+ void (*exec_fun)(const char *file, char * const *argv,
+ char * const *env))
{
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. */
+ /* 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;
static char *shell_file;
- static char *exec_file;
+ static const char *exec_file;
char **save_our_env;
int shell = 0;
- static char **argv;
+ std::vector<char *> argv;
const char *inferior_io_terminal = get_inferior_io_terminal ();
+ struct inferior *inf;
+ int i;
+ int save_errno;
+ struct ui *save_ui;
/* If no exec file handed to us, get it from the exec-file command
-- with a good, common error message if none is specified. */
- exec_file = exec_file_arg;
- if (exec_file == 0)
+ if (exec_file_arg == NULL)
exec_file = get_exec_file (1);
+ else
+ exec_file = exec_file_arg;
- /* STARTUP_WITH_SHELL is defined in inferior.h. If 0,e we'll just
- do a fork/exec, no shell, so don't bother figuring out what
- shell. */
+ /* 'startup_with_shell' is declared in inferior.h and bound to the
+ "set startup-with-shell" option. If 0, we'll just do a
+ fork/exec, no shell, so don't bother figuring out what shell. */
shell_file = shell_file_arg;
- if (STARTUP_WITH_SHELL)
+ if (startup_with_shell)
{
/* Figure out what shell to start up the user program under. */
if (shell_file == NULL)
shell = 1;
}
- /* 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
-
if (!shell)
{
- /* We're going to call execvp. Create argument vector.
- Calculate an upper bound on the length of the vector by
- assuming that every other character is a separate
- argument. */
- int argc = (strlen (allargs) + 1) / 2 + 2;
- argv = (char **) xmalloc (argc * sizeof (*argv));
- argv[0] = exec_file;
- breakup_args (allargs, &argv[1]);
+ /* We're going to call execvp. Create argument vector. */
+ argv.push_back (xstrdup (exec_file));
+ breakup_args (allargs, argv);
}
else
{
/* We're going to call a shell. */
-
- /* Now add exec_file, quoting as necessary. */
-
- char *p;
+ std::string shell_command;
+ const char *p;
int need_to_quote;
const int escape_bang = escape_bang_in_quoted_argument (shell_file);
- strcat (shell_command, "exec ");
+ shell_command = std::string ("exec ");
+
+ /* Add any exec wrapper. That may be a program name with arguments, so
+ the user must handle quoting. */
+ if (exec_wrapper)
+ {
+ shell_command += exec_wrapper;
+ shell_command += ' ';
+ }
+
+ /* Now add exec_file, quoting as necessary. */
/* 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
end_scan:
if (need_to_quote)
{
- strcat (shell_command, "'");
+ shell_command += '\'';
for (p = exec_file; *p != '\0'; ++p)
{
if (*p == '\'')
- strcat (shell_command, "'\\''");
+ shell_command += "'\\''";
else if (*p == '!' && escape_bang)
- strcat (shell_command, "\\!");
+ shell_command += "\\!";
else
- strncat (shell_command, p, 1);
+ shell_command += *p;
}
- strcat (shell_command, "'");
+ shell_command += '\'';
}
else
- strcat (shell_command, exec_file);
+ shell_command += exec_file;
- strcat (shell_command, " ");
- strcat (shell_command, allargs);
- }
+ shell_command += " " + allargs;
- /* On some systems an exec will fail if the executable is open. */
- close_exec_file ();
+ /* If we decided above to start up with a shell, we exec the
+ shell, "-c" says to interpret the next arg as a shell command
+ to execute, and this command is "exec <target-program>
+ <args>". We xstrdup all the strings here because they will
+ be free'd later in the code. */
+ argv.push_back (xstrdup (shell_file));
+ argv.push_back (xstrdup ("-c"));
+ argv.push_back (xstrdup (shell_command.c_str ()));
+ argv.push_back (NULL);
+ }
/* 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;
+ /* Likewise the current UI. */
+ save_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. */
- gdb_flush (gdb_stdout);
- gdb_flush (gdb_stderr);
+ the parent and child flushing the same data after the fork. */
+ gdb_flush (main_ui->m_gdb_stdout);
+ gdb_flush (main_ui->m_gdb_stderr);
/* If there's any initialization of the target layers that must
happen to prepare to handle the child we're about fork, do it
if (pid == 0)
{
+ /* Switch to the main UI, so that gdb_std{in/out/err} in the
+ child are mapped to std{in/out/err}. This makes it possible
+ to use fprintf_unfiltered/warning/error/etc. in the child
+ from here on. */
+ current_ui = main_ui;
+
+ /* Close all file descriptors except those that gdb inherited
+ (usually 0/1/2), so they don't leak to the inferior. Note
+ that this closes the file descriptors of all secondary
+ UIs. */
+ close_most_fds ();
+
if (debug_fork)
sleep (debug_fork);
- /* Run inferior in a separate process group. */
- debug_setpgrp = gdb_setpgid ();
- if (debug_setpgrp == -1)
- perror ("setpgrp failed in child");
+ /* 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"));
+ }
/* Ask the tty subsystem to switch to the one we specified
earlier (or to share the current terminal, if none was
initialize_signals for how we get the right signal handlers
for the inferior. */
- /* "Trace me, Dr. Memory!" */
+ /* "Trace me, Dr. Memory!" */
(*traceme_fun) ();
/* The call above set this process (the "child") as debuggable
saying "not parent". Sorry; you'll have to use print
statements! */
+ restore_original_signals_state ();
+
/* 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
path to find $SHELL. Rich Pixley says so, and I agree. */
environ = env;
- /* If we decided above to start up with a shell, we exec the
- shell, "-c" says to interpret the next arg as a shell command
- to execute, and this command is "exec <target-program>
- <args>". */
- if (shell)
- {
- execlp (shell_file, shell_file, "-c", shell_command, (char *) 0);
-
- /* If we get here, it's an error. */
- fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file,
- safe_strerror (errno));
- gdb_flush (gdb_stderr);
- _exit (0177);
- }
+ if (exec_fun != NULL)
+ (*exec_fun) (argv[0], &argv[0], env);
else
- {
- /* Otherwise, we directly exec the target program with
- execvp. */
- int i;
- char *errstring;
-
- execvp (exec_file, argv);
-
- /* If we get here, it's an error. */
- errstring = safe_strerror (errno);
- fprintf_unfiltered (gdb_stderr, "Cannot exec %s ", exec_file);
-
- i = 1;
- while (argv[i] != NULL)
- {
- if (i != 1)
- fprintf_unfiltered (gdb_stderr, " ");
- fprintf_unfiltered (gdb_stderr, "%s", argv[i]);
- i++;
- }
- fprintf_unfiltered (gdb_stderr, ".\n");
-#if 0
- /* This extra info seems to be useless. */
- fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring);
-#endif
- gdb_flush (gdb_stderr);
- _exit (0177);
- }
+ execvp (argv[0], &argv[0]);
+
+ /* If we get here, it's an error. */
+ save_errno = errno;
+ fprintf_unfiltered (gdb_stderr, "Cannot exec %s", argv[0]);
+ for (i = 1; argv[i] != NULL; i++)
+ fprintf_unfiltered (gdb_stderr, " %s", argv[i]);
+ fprintf_unfiltered (gdb_stderr, ".\n");
+ fprintf_unfiltered (gdb_stderr, "Error: %s\n",
+ safe_strerror (save_errno));
+ gdb_flush (gdb_stderr);
+ _exit (0177);
}
+ free_vector_argv (argv);
+
/* Restore our environment in case a vforked child clob'd it. */
environ = save_our_env;
- init_thread_list ();
+ /* Likewise the current UI. */
+ current_ui = save_ui;
+
+ if (!have_inferiors ())
+ init_thread_list ();
+
+ inf = current_inferior ();
+
+ inferior_appeared (inf, pid);
/* Needed for wait_for_inferior stuff below. */
inferior_ptid = pid_to_ptid (pid);
+ new_tty_postfork ();
+
+ /* We have something that executes now. We'll be running through
+ the shell at this point, but the pid shouldn't change. Targets
+ supporting MT should fill this task's ptid with more data as soon
+ as they can. */
+ add_thread_silent (inferior_ptid);
+
/* Now that we have a child process, make it our target, and
initialize anything target-vector-specific that needs
initializing. */
- (*init_trace_fun) (pid);
+ if (init_trace_fun)
+ (*init_trace_fun) (pid);
/* 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. */
+ return pid;
}
/* Accept NTRAPS traps from the inferior. */
{
int pending_execs = ntraps;
int terminal_initted = 0;
+ ptid_t resume_ptid;
+
+ if (startup_with_shell)
+ {
+ /* One trap extra for exec'ing the shell. */
+ pending_execs++;
+ }
+
+ if (target_supports_multi_process ())
+ resume_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
+ else
+ resume_ptid = minus_one_ptid;
/* 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. */
- clear_proceed_status ();
-
- init_wait_for_inferior ();
-
- if (STARTUP_WITH_SHELL)
- inferior_ignoring_startup_exec_events = ntraps;
- else
- inferior_ignoring_startup_exec_events = 0;
- inferior_ignoring_leading_exec_events =
- target_reported_exec_events_per_exec_call () - 1;
+ if (exec_wrapper)
+ pending_execs++;
while (1)
{
- /* Make wait_for_inferior be quiet. */
- stop_soon = STOP_QUIETLY;
- wait_for_inferior ();
- if (stop_signal != TARGET_SIGNAL_TRAP)
+ enum gdb_signal resume_signal = GDB_SIGNAL_0;
+ ptid_t event_ptid;
+
+ struct target_waitstatus ws;
+ memset (&ws, 0, sizeof (ws));
+ event_ptid = target_wait (resume_ptid, &ws, 0);
+
+ if (ws.kind == TARGET_WAITKIND_IGNORE)
+ /* The inferior didn't really stop, keep waiting. */
+ continue;
+
+ switch (ws.kind)
{
- /* Let shell child handle its own signals in its own way.
- FIXME: what if child has exited? Must exit loop
- somehow. */
- resume (0, stop_signal);
+ case TARGET_WAITKIND_SPURIOUS:
+ case TARGET_WAITKIND_LOADED:
+ case TARGET_WAITKIND_FORKED:
+ case TARGET_WAITKIND_VFORKED:
+ case TARGET_WAITKIND_SYSCALL_ENTRY:
+ case TARGET_WAITKIND_SYSCALL_RETURN:
+ /* Ignore gracefully during startup of the inferior. */
+ switch_to_thread (event_ptid);
+ break;
+
+ case TARGET_WAITKIND_SIGNALLED:
+ target_terminal_ours ();
+ target_mourn_inferior (event_ptid);
+ error (_("During startup program terminated with signal %s, %s."),
+ gdb_signal_to_name (ws.value.sig),
+ gdb_signal_to_string (ws.value.sig));
+ return;
+
+ case TARGET_WAITKIND_EXITED:
+ target_terminal_ours ();
+ target_mourn_inferior (event_ptid);
+ if (ws.value.integer)
+ error (_("During startup program exited with code %d."),
+ ws.value.integer);
+ else
+ error (_("During startup program exited normally."));
+ return;
+
+ case TARGET_WAITKIND_EXECD:
+ /* Handle EXEC signals as if they were SIGTRAP signals. */
+ xfree (ws.value.execd_pathname);
+ resume_signal = GDB_SIGNAL_TRAP;
+ switch_to_thread (event_ptid);
+ break;
+
+ case TARGET_WAITKIND_STOPPED:
+ resume_signal = ws.value.sig;
+ switch_to_thread (event_ptid);
+ break;
+ }
+
+ if (resume_signal != GDB_SIGNAL_TRAP)
+ {
+ /* Let shell child handle its own signals in its own way. */
+ target_continue (resume_ptid, resume_signal);
}
else
{
if (--pending_execs == 0)
break;
- resume (0, TARGET_SIGNAL_0); /* Just make it go on. */
+ /* Just make it go on. */
+ target_continue_no_signal (resume_ptid);
}
}
- stop_soon = NO_STOP_QUIETLY;
+
+ /* Mark all threads non-executing. */
+ set_executing (resume_ptid, 0);
+}
+
+/* Implement the "unset exec-wrapper" command. */
+
+static void
+unset_exec_wrapper_command (char *args, int from_tty)
+{
+ xfree (exec_wrapper);
+ exec_wrapper = NULL;
+}
+
+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);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_fork_child;
+
+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