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Diffstat (limited to 'builtins/exec.def')
| -rw-r--r-- | builtins/exec.def | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/builtins/exec.def b/builtins/exec.def new file mode 100644 index 0000000..add9082 --- /dev/null +++ b/builtins/exec.def @@ -0,0 +1,276 @@ +This file is exec.def, from which is created exec.c. +It implements the builtin "exec" in Bash. + +Copyright (C) 1987-2021 Free Software Foundation, Inc. + +This file is part of GNU Bash, the Bourne Again SHell. + +Bash 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. + +Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>. + +$PRODUCES exec.c + +$BUILTIN exec +$FUNCTION exec_builtin +$SHORT_DOC exec [-cl] [-a name] [command [argument ...]] [redirection ...] +Replace the shell with the given command. + +Execute COMMAND, replacing this shell with the specified program. +ARGUMENTS become the arguments to COMMAND. If COMMAND is not specified, +any redirections take effect in the current shell. + +Options: + -a name pass NAME as the zeroth argument to COMMAND + -c execute COMMAND with an empty environment + -l place a dash in the zeroth argument to COMMAND + +If the command cannot be executed, a non-interactive shell exits, unless +the shell option `execfail' is set. + +Exit Status: +Returns success unless COMMAND is not found or a redirection error occurs. +$END + +#include <config.h> + +#include "../bashtypes.h" +#include "posixstat.h" +#include <signal.h> +#include <errno.h> + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include <stdio.h> + +#include "../bashansi.h" +#include "../bashintl.h" + +#include "../shell.h" +#include "../execute_cmd.h" +#include "../findcmd.h" +#if defined (JOB_CONTROL) +# include "../jobs.h" +#endif +#include "../flags.h" +#include "../trap.h" +#if defined (HISTORY) +# include "../bashhist.h" +#endif +#include "common.h" +#include "bashgetopt.h" +#include "input.h" + +/* Not all systems declare ERRNO in errno.h... and some systems #define it! */ +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +extern REDIRECT *redirection_undo_list; +extern char *exec_argv0; + +int no_exit_on_failed_exec; + +/* If the user wants this to look like a login shell, then + prepend a `-' onto NAME and return the new name. */ +static char * +mkdashname (name) + char *name; +{ + char *ret; + + ret = (char *)xmalloc (2 + strlen (name)); + ret[0] = '-'; + strcpy (ret + 1, name); + return ret; +} + +int +exec_builtin (list) + WORD_LIST *list; +{ + int exit_value = EXECUTION_FAILURE; + int cleanenv, login, opt, orig_job_control; + char *argv0, *command, **args, **env, *newname, *com2; + + cleanenv = login = orig_job_control = 0; + exec_argv0 = argv0 = (char *)NULL; + + reset_internal_getopt (); + while ((opt = internal_getopt (list, "cla:")) != -1) + { + switch (opt) + { + case 'c': + cleanenv = 1; + break; + case 'l': + login = 1; + break; + case 'a': + argv0 = list_optarg; + break; + CASE_HELPOPT; + default: + builtin_usage (); + return (EX_USAGE); + } + } + list = loptend; + + /* First, let the redirections remain. */ + dispose_redirects (redirection_undo_list); + redirection_undo_list = (REDIRECT *)NULL; + + if (list == 0) + return (EXECUTION_SUCCESS); + +#if defined (RESTRICTED_SHELL) + if (restricted) + { + sh_restricted ((char *)NULL); + return (EXECUTION_FAILURE); + } +#endif /* RESTRICTED_SHELL */ + + args = strvec_from_word_list (list, 1, 0, (int *)NULL); + env = (char **)0; + + /* A command with a slash anywhere in its name is not looked up in $PATH. */ + command = absolute_program (args[0]) ? args[0] : search_for_command (args[0], 1); + + if (command == 0) + { + if (file_isdir (args[0])) + { +#if defined (EISDIR) + builtin_error (_("%s: cannot execute: %s"), args[0], strerror (EISDIR)); +#else + builtin_error (_("%s: cannot execute: %s"), args[0], strerror (errno)); +#endif + exit_value = EX_NOEXEC; + } + else + { + sh_notfound (args[0]); + exit_value = EX_NOTFOUND; /* As per Posix.2, 3.14.6 */ + } + goto failed_exec; + } + + com2 = full_pathname (command); + if (com2) + { + if (command != args[0]) + free (command); + command = com2; + } + + if (argv0) + { + free (args[0]); + args[0] = login ? mkdashname (argv0) : savestring (argv0); + exec_argv0 = savestring (args[0]); + } + else if (login) + { + newname = mkdashname (args[0]); + free (args[0]); + args[0] = newname; + } + + /* Decrement SHLVL by 1 so a new shell started here has the same value, + preserving the appearance. After we do that, we need to change the + exported environment to include the new value. If we've already forked + and are in a subshell, we don't want to decrement the shell level, + since we are `increasing' the level */ + + if (cleanenv == 0 && (subshell_environment & SUBSHELL_PAREN) == 0) + adjust_shell_level (-1); + + if (cleanenv) + { + env = strvec_create (1); + env[0] = (char *)0; + } + else + { + maybe_make_export_env (); + env = export_env; + } + +#if defined (HISTORY) + if (interactive_shell && subshell_environment == 0) + maybe_save_shell_history (); +#endif /* HISTORY */ + + reset_signal_handlers (); /* leave trap strings in place */ + +#if defined (JOB_CONTROL) + orig_job_control = job_control; /* XXX - was also interactive_shell */ + if (subshell_environment == 0) + end_job_control (); + if (interactive || job_control) + default_tty_job_signals (); /* undo initialize_job_signals */ +#endif /* JOB_CONTROL */ + +#if defined (BUFFERED_INPUT) + if (default_buffered_input >= 0) + sync_buffered_stream (default_buffered_input); +#endif + + exit_value = shell_execve (command, args, env); + + /* We have to set this to NULL because shell_execve has called realloc() + to stuff more items at the front of the array, which may have caused + the memory to be freed by realloc(). We don't want to free it twice. */ + args = (char **)NULL; + if (cleanenv == 0) + adjust_shell_level (1); + + if (exit_value == EX_NOTFOUND) /* no duplicate error message */ + goto failed_exec; + else if (executable_file (command) == 0) + { + builtin_error (_("%s: cannot execute: %s"), command, strerror (errno)); + exit_value = EX_NOEXEC; /* As per Posix.2, 3.14.6 */ + } + else + file_error (command); + +failed_exec: + FREE (command); + + if (subshell_environment || (interactive == 0 && no_exit_on_failed_exec == 0)) + exit_shell (last_command_exit_value = exit_value); + + if (args) + strvec_dispose (args); + + if (env && env != export_env) + strvec_dispose (env); + + /* If we're not exiting after the exec fails, we restore the shell signal + handlers and then modify the signal dispositions based on the trap strings + before the failed exec. */ + initialize_signals (1); + restore_traps (); + +#if defined (JOB_CONTROL) + if (orig_job_control) + restart_job_control (); +#endif /* JOB_CONTROL */ + + return (exit_value); +} |