mirror of https://github.com/n-hys/bash.git
274 lines
6.6 KiB
Modula-2
274 lines
6.6 KiB
Modula-2
This file is exec.def, from which is created exec.c.
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It implements the builtin "exec" in Bash.
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Copyright (C) 1987-2019 Free Software Foundation, Inc.
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This file is part of GNU Bash, the Bourne Again SHell.
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Bash 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 3 of the License, or
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(at your option) any later version.
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Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>.
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$PRODUCES exec.c
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$BUILTIN exec
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$FUNCTION exec_builtin
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$SHORT_DOC exec [-cl] [-a name] [command [argument ...]] [redirection ...]
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Replace the shell with the given command.
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Execute COMMAND, replacing this shell with the specified program.
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ARGUMENTS become the arguments to COMMAND. If COMMAND is not specified,
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any redirections take effect in the current shell.
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Options:
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-a name pass NAME as the zeroth argument to COMMAND
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-c execute COMMAND with an empty environment
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-l place a dash in the zeroth argument to COMMAND
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If the command cannot be executed, a non-interactive shell exits, unless
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the shell option `execfail' is set.
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Exit Status:
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Returns success unless COMMAND is not found or a redirection error occurs.
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$END
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#include <config.h>
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#include "../bashtypes.h"
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#include "posixstat.h"
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#include <signal.h>
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#include <errno.h>
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#if defined (HAVE_UNISTD_H)
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# include <unistd.h>
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#endif
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#include <stdio.h>
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#include "../bashansi.h"
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#include "../bashintl.h"
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#include "../shell.h"
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#include "../execute_cmd.h"
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#include "../findcmd.h"
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#if defined (JOB_CONTROL)
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# include "../jobs.h"
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#endif
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#include "../flags.h"
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#include "../trap.h"
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#if defined (HISTORY)
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# include "../bashhist.h"
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#endif
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#include "common.h"
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#include "bashgetopt.h"
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#include "input.h"
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/* Not all systems declare ERRNO in errno.h... and some systems #define it! */
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#if !defined (errno)
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extern int errno;
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#endif /* !errno */
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extern REDIRECT *redirection_undo_list;
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extern char *exec_argv0;
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int no_exit_on_failed_exec;
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/* If the user wants this to look like a login shell, then
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prepend a `-' onto NAME and return the new name. */
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static char *
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mkdashname (name)
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char *name;
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{
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char *ret;
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ret = (char *)xmalloc (2 + strlen (name));
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ret[0] = '-';
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strcpy (ret + 1, name);
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return ret;
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}
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int
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exec_builtin (list)
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WORD_LIST *list;
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{
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int exit_value = EXECUTION_FAILURE;
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int cleanenv, login, opt, orig_job_control;
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char *argv0, *command, **args, **env, *newname, *com2;
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cleanenv = login = 0;
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exec_argv0 = argv0 = (char *)NULL;
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reset_internal_getopt ();
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while ((opt = internal_getopt (list, "cla:")) != -1)
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{
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switch (opt)
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{
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case 'c':
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cleanenv = 1;
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break;
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case 'l':
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login = 1;
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break;
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case 'a':
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argv0 = list_optarg;
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break;
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CASE_HELPOPT;
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default:
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builtin_usage ();
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return (EX_USAGE);
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}
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}
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list = loptend;
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/* First, let the redirections remain. */
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dispose_redirects (redirection_undo_list);
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redirection_undo_list = (REDIRECT *)NULL;
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if (list == 0)
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return (EXECUTION_SUCCESS);
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#if defined (RESTRICTED_SHELL)
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if (restricted)
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{
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sh_restricted ((char *)NULL);
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return (EXECUTION_FAILURE);
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}
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#endif /* RESTRICTED_SHELL */
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args = strvec_from_word_list (list, 1, 0, (int *)NULL);
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env = (char **)0;
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/* A command with a slash anywhere in its name is not looked up in $PATH. */
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command = absolute_program (args[0]) ? args[0] : search_for_command (args[0], 1);
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if (command == 0)
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{
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if (file_isdir (args[0]))
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{
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#if defined (EISDIR)
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builtin_error (_("%s: cannot execute: %s"), args[0], strerror (EISDIR));
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#else
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builtin_error (_("%s: cannot execute: %s"), args[0], strerror (errno));
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#endif
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exit_value = EX_NOEXEC;
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}
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else
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{
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sh_notfound (args[0]);
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exit_value = EX_NOTFOUND; /* As per Posix.2, 3.14.6 */
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}
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goto failed_exec;
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}
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com2 = full_pathname (command);
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if (com2)
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{
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if (command != args[0])
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free (command);
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command = com2;
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}
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if (argv0)
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{
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free (args[0]);
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args[0] = login ? mkdashname (argv0) : savestring (argv0);
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exec_argv0 = savestring (args[0]);
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}
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else if (login)
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{
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newname = mkdashname (args[0]);
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free (args[0]);
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args[0] = newname;
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}
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/* Decrement SHLVL by 1 so a new shell started here has the same value,
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preserving the appearance. After we do that, we need to change the
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exported environment to include the new value. If we've already forked
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and are in a subshell, we don't want to decrement the shell level,
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since we are `increasing' the level */
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if (cleanenv == 0 && (subshell_environment & SUBSHELL_PAREN) == 0)
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adjust_shell_level (-1);
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if (cleanenv)
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{
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env = strvec_create (1);
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env[0] = (char *)0;
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}
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else
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{
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maybe_make_export_env ();
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env = export_env;
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}
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#if defined (HISTORY)
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if (interactive_shell && subshell_environment == 0)
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maybe_save_shell_history ();
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#endif /* HISTORY */
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restore_original_signals ();
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#if defined (JOB_CONTROL)
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orig_job_control = job_control; /* XXX - was also interactive_shell */
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if (subshell_environment == 0)
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end_job_control ();
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if (interactive || job_control)
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default_tty_job_signals (); /* undo initialize_job_signals */
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#endif /* JOB_CONTROL */
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#if defined (BUFFERED_INPUT)
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if (default_buffered_input >= 0)
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sync_buffered_stream (default_buffered_input);
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#endif
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exit_value = shell_execve (command, args, env);
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/* We have to set this to NULL because shell_execve has called realloc()
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to stuff more items at the front of the array, which may have caused
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the memory to be freed by realloc(). We don't want to free it twice. */
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args = (char **)NULL;
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if (cleanenv == 0)
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adjust_shell_level (1);
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if (exit_value == EX_NOTFOUND) /* no duplicate error message */
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goto failed_exec;
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else if (executable_file (command) == 0)
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{
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builtin_error (_("%s: cannot execute: %s"), command, strerror (errno));
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exit_value = EX_NOEXEC; /* As per Posix.2, 3.14.6 */
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}
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else
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file_error (command);
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failed_exec:
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FREE (command);
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if (subshell_environment || (interactive == 0 && no_exit_on_failed_exec == 0))
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exit_shell (exit_value);
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if (args)
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strvec_dispose (args);
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if (env && env != export_env)
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strvec_dispose (env);
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initialize_traps ();
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initialize_signals (1);
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#if defined (JOB_CONTROL)
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if (orig_job_control)
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restart_job_control ();
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#endif /* JOB_CONTROL */
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return (exit_value);
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}
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