/* evalstring.c - evaluate a string as one or more shell commands. */
/* Copyright (C) 1996-2015 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/>.
*/
#include <config.h>
#if defined (HAVE_UNISTD_H)
# ifdef _MINIX
# include <sys/types.h>
# endif
# include <unistd.h>
#endif
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include "filecntl.h"
#include "../bashansi.h"
#include "../shell.h"
#include "../jobs.h"
#include "../builtins.h"
#include "../flags.h"
#include "../input.h"
#include "../execute_cmd.h"
#include "../redir.h"
#include "../trap.h"
#include "../bashintl.h"
#include <y.tab.h>
#if defined (HISTORY)
# include "../bashhist.h"
#endif
#include "common.h"
#include "builtext.h"
#if !defined (errno)
extern int errno;
#endif
#define IS_BUILTIN(s) (builtin_address_internal(s, 0) != (struct builtin *)NULL)
extern int indirection_level, subshell_environment;
extern int line_number, line_number_for_err_trap;
extern int current_token, shell_eof_token;
extern int last_command_exit_value;
extern int running_trap;
extern int loop_level;
extern int executing_list;
extern int comsub_ignore_return;
extern int posixly_correct;
extern int return_catch_flag, return_catch_value;
extern sh_builtin_func_t *this_shell_builtin;
extern char *the_printed_command_except_trap;
int parse_and_execute_level = 0;
static int cat_file __P((REDIRECT *));
#define PE_TAG "parse_and_execute top"
#define PS_TAG "parse_string top"
#if defined (HISTORY)
static void
set_history_remembering ()
{
remember_on_history = enable_history_list;
}
#endif
static void
restore_lastcom (x)
char *x;
{
FREE (the_printed_command_except_trap);
the_printed_command_except_trap = x;
}
int
should_suppress_fork (command)
COMMAND *command;
{
return (startup_state == 2 && parse_and_execute_level == 1 &&
running_trap == 0 &&
*bash_input.location.string == '\0' &&
command->type == cm_simple &&
signal_is_trapped (EXIT_TRAP) == 0 &&
signal_is_trapped (ERROR_TRAP) == 0 &&
any_signals_trapped () < 0 &&
command->redirects == 0 && command->value.Simple->redirects == 0 &&
((command->flags & CMD_TIME_PIPELINE) == 0) &&
((command->flags & CMD_INVERT_RETURN) == 0));
}
void
optimize_fork (command)
COMMAND *command;
{
if (command->type == cm_connection &&
(command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR) &&
should_suppress_fork (command->value.Connection->second))
{
command->value.Connection->second->flags |= CMD_NO_FORK;
command->value.Connection->second->value.Simple->flags |= CMD_NO_FORK;
}
}
/* How to force parse_and_execute () to clean up after itself. */
void
parse_and_execute_cleanup ()
{
if (running_trap)
{
run_trap_cleanup (running_trap - 1);
unfreeze_jobs_list ();
}
if (have_unwind_protects ())
run_unwind_frame (PE_TAG);
else
parse_and_execute_level = 0; /* XXX */
}
static void
parse_prologue (string, flags, tag)
char *string;
int flags;
char *tag;
{
char *orig_string, *lastcom;
int x;
orig_string = string;
/* Unwind protect this invocation of parse_and_execute (). */
begin_unwind_frame (tag);
unwind_protect_int (parse_and_execute_level);
unwind_protect_jmp_buf (top_level);
unwind_protect_int (indirection_level);
unwind_protect_int (line_number);
unwind_protect_int (line_number_for_err_trap);
unwind_protect_int (loop_level);
unwind_protect_int (executing_list);
unwind_protect_int (comsub_ignore_return);
if (flags & (SEVAL_NONINT|SEVAL_INTERACT))
unwind_protect_int (interactive);
#if defined (HISTORY)
if (parse_and_execute_level == 0)
add_unwind_protect (set_history_remembering, (char *)NULL);
else
unwind_protect_int (remember_on_history); /* can be used in scripts */
# if defined (BANG_HISTORY)
unwind_protect_int (history_expansion_inhibited);
# endif /* BANG_HISTORY */
#endif /* HISTORY */
if (interactive_shell)
{
x = get_current_prompt_level ();
add_unwind_protect (set_current_prompt_level, x);
}
if (the_printed_command_except_trap)
{
lastcom = savestring (the_printed_command_except_trap);
add_unwind_protect (restore_lastcom, lastcom);
}
add_unwind_protect (pop_stream, (char *)NULL);
if (parser_expanding_alias ())
add_unwind_protect (parser_restore_alias, (char *)NULL);
if (orig_string && ((flags & SEVAL_NOFREE) == 0))
add_unwind_protect (xfree, orig_string);
end_unwind_frame ();
if (flags & (SEVAL_NONINT|SEVAL_INTERACT))
interactive = (flags & SEVAL_NONINT) ? 0 : 1;
#if defined (HISTORY)
if (flags & SEVAL_NOHIST)
bash_history_disable ();
# if defined (BANG_HISTORY)
if (flags & SEVAL_NOHISTEXP)
history_expansion_inhibited = 1;
# endif /* BANG_HISTORY */
#endif /* HISTORY */
}
/* Parse and execute the commands in STRING. Returns whatever
execute_command () returns. This frees STRING. FLAGS is a
flags word; look in common.h for the possible values. Actions
are:
(flags & SEVAL_NONINT) -> interactive = 0;
(flags & SEVAL_INTERACT) -> interactive = 1;
(flags & SEVAL_NOHIST) -> call bash_history_disable ()
(flags & SEVAL_NOFREE) -> don't free STRING when finished
(flags & SEVAL_RESETLINE) -> reset line_number to 1
(flags & SEVAL_NOHISTEXP) -> history_expansion_inhibited -> 1
*/
int
parse_and_execute (string, from_file, flags)
char *string;
const char *from_file;
int flags;
{
int code, lreset;
volatile int should_jump_to_top_level, last_result;
COMMAND *volatile command;
volatile sigset_t pe_sigmask;
parse_prologue (string, flags, PE_TAG);
parse_and_execute_level++;
lreset = flags & SEVAL_RESETLINE;
#if defined (HAVE_POSIX_SIGNALS)
/* If we longjmp and are going to go on, use this to restore signal mask */
sigemptyset ((sigset_t *)&pe_sigmask);
sigprocmask (SIG_BLOCK, (sigset_t *)NULL, (sigset_t *)&pe_sigmask);
#endif
/* Reset the line number if the caller wants us to. If we don't reset the
line number, we have to subtract one, because we will add one just
before executing the next command (resetting the line number sets it to
0; the first line number is 1). */
push_stream (lreset);
if (parser_expanding_alias ())
/* push current shell_input_line */
parser_save_alias ();
if (lreset == 0)
line_number--;
indirection_level++;
code = should_jump_to_top_level = 0;
last_result = EXECUTION_SUCCESS;
/* We need to reset enough of the token state so we can start fresh. */
if (current_token == yacc_EOF)
current_token = '\n'; /* reset_parser() ? */
with_input_from_string (string, from_file);
clear_shell_input_line ();
while (*(bash_input.location.string))
{
command = (COMMAND *)NULL;
if (interrupt_state)
{
last_result = EXECUTION_FAILURE;
break;
}
/* Provide a location for functions which `longjmp (top_level)' to
jump to. This prevents errors in substitution from restarting
the reader loop directly, for example. */
code = setjmp_nosigs (top_level);
if (code)
{
should_jump_to_top_level = 0;
switch (code)
{
case ERREXIT:
/* variable_context -> 0 is what eval.c:reader_loop() does in
these circumstances. Don't bother with cleanup here because
we don't want to run the function execution cleanup stuff
that will cause pop_context and other functions to run.
XXX - change that if we want the function context to be
unwound. */
if (exit_immediately_on_error && variable_context)
{
discard_unwind_frame ("pe_dispose");
variable_context = 0; /* not in a function */
}
should_jump_to_top_level = 1;
goto out;
case FORCE_EOF:
case EXITPROG:
if (command)
run_unwind_frame ("pe_dispose");
/* Remember to call longjmp (top_level) after the old
value for it is restored. */
should_jump_to_top_level = 1;
goto out;
case DISCARD:
if (command)
run_unwind_frame ("pe_dispose");
last_result = last_command_exit_value = EXECUTION_FAILURE; /* XXX */
if (subshell_environment)
{
should_jump_to_top_level = 1;
goto out;
}
else
{
#if 0
dispose_command (command); /* pe_dispose does this */
#endif
#if defined (HAVE_POSIX_SIGNALS)
sigprocmask (SIG_SETMASK, (sigset_t *)&pe_sigmask, (sigset_t *)NULL);
#endif
continue;
}
default:
command_error ("parse_and_execute", CMDERR_BADJUMP, code, 0);
break;
}
}
if (parse_command () == 0)
{
if ((flags & SEVAL_PARSEONLY) || (interactive_shell == 0 && read_but_dont_execute))
{
last_result = EXECUTION_SUCCESS;
dispose_command (global_command);
global_command = (COMMAND *)NULL;
}
else if (command = global_command)
{
struct fd_bitmap *bitmap;
if (flags & SEVAL_FUNCDEF)
{
char *x;
/* If the command parses to something other than a straight
function definition, or if we have not consumed the entire
string, or if the parser has transformed the function
name (as parsing will if it begins or ends with shell
whitespace, for example), reject the attempt */
if (command->type != cm_function_def ||
((x = parser_remaining_input ()) && *x) ||
(STREQ (from_file, command->value.Function_def->name->word) == 0))
{
internal_warning (_("%s: ignoring function definition attempt"), from_file);
should_jump_to_top_level = 0;
last_result = last_command_exit_value = EX_BADUSAGE;
reset_parser ();
break;
}
}
bitmap = new_fd_bitmap (FD_BITMAP_SIZE);
begin_unwind_frame ("pe_dispose");
add_unwind_protect (dispose_fd_bitmap, bitmap);
add_unwind_protect (dispose_command, command); /* XXX */
global_command = (COMMAND *)NULL;
if ((subshell_environment & SUBSHELL_COMSUB) && comsub_ignore_return)
command->flags |= CMD_IGNORE_RETURN;
#if defined (ONESHOT)
/*
* IF
* we were invoked as `bash -c' (startup_state == 2) AND
* parse_and_execute has not been called recursively AND
* we're not running a trap AND
* we have parsed the full command (string == '\0') AND
* we're not going to run the exit trap AND
* we have a simple command without redirections AND
* the command is not being timed AND
* the command's return status is not being inverted AND
* there aren't any traps in effect
* THEN
* tell the execution code that we don't need to fork
*/
if (should_suppress_fork (command))
{
command->flags |= CMD_NO_FORK;
command->value.Simple->flags |= CMD_NO_FORK;
}
else if (command->type == cm_connection)
optimize_fork (command);
#endif /* ONESHOT */
/* See if this is a candidate for $( <file ). */
if (startup_state == 2 &&
(subshell_environment & SUBSHELL_COMSUB) &&
*bash_input.location.string == '\0' &&
command->type == cm_simple && !command->redirects &&
(command->flags & CMD_TIME_PIPELINE) == 0 &&
command->value.Simple->words == 0 &&
command->value.Simple->redirects &&
command->value.Simple->redirects->next == 0 &&
command->value.Simple->redirects->instruction == r_input_direction &&
command->value.Simple->redirects->redirector.dest == 0)
{
int r;
r = cat_file (command->value.Simple->redirects);
last_result = (r < 0) ? EXECUTION_FAILURE : EXECUTION_SUCCESS;
}
else
last_result = execute_command_internal
(command, 0, NO_PIPE, NO_PIPE, bitmap);
dispose_command (command);
dispose_fd_bitmap (bitmap);
discard_unwind_frame ("pe_dispose");
if (flags & SEVAL_ONECMD)
{
reset_parser ();
break;
}
}
}
else
{
last_result = EXECUTION_FAILURE;
if (interactive_shell == 0 && this_shell_builtin &&
(this_shell_builtin == source_builtin || this_shell_builtin == eval_builtin) &&
last_command_exit_value == EX_BADSYNTAX && posixly_correct)
{
should_jump_to_top_level = 1;
code = ERREXIT;
last_command_exit_value = EX_BADUSAGE;
}
/* Since we are shell compatible, syntax errors in a script
abort the execution of the script. Right? */
break;
}
}
out:
run_unwind_frame (PE_TAG);
if (interrupt_state && parse_and_execute_level == 0)
{
/* An interrupt during non-interactive execution in an
interactive shell (e.g. via $PROMPT_COMMAND) should
not cause the shell to exit. */
interactive = interactive_shell;
throw_to_top_level ();
}
if (should_jump_to_top_level)
jump_to_top_level (code);
return (last_result);
}
/* Parse a command contained in STRING according to FLAGS and return the
number of characters consumed from the string. If non-NULL, set *ENDP
to the position in the string where the parse ended. Used to validate
command substitutions during parsing to obey Posix rules about finding
the end of the command and balancing parens. */
int
parse_string (string, from_file, flags, endp)
char *string;
const char *from_file;
int flags;
char **endp;
{
int code, nc;
volatile int should_jump_to_top_level;
COMMAND *volatile command, *oglobal;
char *ostring;
volatile sigset_t ps_sigmask;
parse_prologue (string, flags, PS_TAG);
#if defined (HAVE_POSIX_SIGNALS)
/* If we longjmp and are going to go on, use this to restore signal mask */
sigemptyset ((sigset_t *)&ps_sigmask);
sigprocmask (SIG_BLOCK, (sigset_t *)NULL, (sigset_t *)&ps_sigmask);
#endif
/*itrace("parse_string: `%s'", string);*/
/* Reset the line number if the caller wants us to. If we don't reset the
line number, we have to subtract one, because we will add one just
before executing the next command (resetting the line number sets it to
0; the first line number is 1). */
push_stream (0);
if (parser_expanding_alias ())
/* push current shell_input_line */
parser_save_alias ();
code = should_jump_to_top_level = 0;
oglobal = global_command;
ostring = string;
with_input_from_string (string, from_file);
while (*(bash_input.location.string))
{
command = (COMMAND *)NULL;
#if 0
if (interrupt_state)
break;
#endif
/* Provide a location for functions which `longjmp (top_level)' to
jump to. */
code = setjmp_nosigs (top_level);
if (code)
{
#if defined (DEBUG)
itrace("parse_string: longjmp executed: code = %d", code);
#endif
should_jump_to_top_level = 0;
switch (code)
{
case FORCE_EOF:
case ERREXIT:
case EXITPROG:
case DISCARD: /* XXX */
if (command)
dispose_command (command);
/* Remember to call longjmp (top_level) after the old
value for it is restored. */
should_jump_to_top_level = 1;
goto out;
default:
#if defined (HAVE_POSIX_SIGNALS)
sigprocmask (SIG_SETMASK, (sigset_t *)&ps_sigmask, (sigset_t *)NULL);
#endif
command_error ("parse_string", CMDERR_BADJUMP, code, 0);
break;
}
}
if (parse_command () == 0)
{
dispose_command (global_command);
global_command = (COMMAND *)NULL;
}
else
{
if ((flags & SEVAL_NOLONGJMP) == 0)
{
should_jump_to_top_level = 1;
code = DISCARD;
}
else
reset_parser (); /* XXX - sets token_to_read */
break;
}
if (current_token == yacc_EOF || current_token == shell_eof_token)
break;
}
out:
global_command = oglobal;
nc = bash_input.location.string - ostring;
if (endp)
*endp = bash_input.location.string;
run_unwind_frame (PS_TAG);
/* If we return < 0, the caller (xparse_dolparen) will jump_to_top_level for
us, after doing cleanup */
if (should_jump_to_top_level)
{
if (parse_and_execute_level == 0)
top_level_cleanup ();
if (code == DISCARD)
return -DISCARD;
jump_to_top_level (code);
}
return (nc);
}
/* Handle a $( < file ) command substitution. This expands the filename,
returning errors as appropriate, then just cats the file to the standard
output. */
static int
cat_file (r)
REDIRECT *r;
{
char *fn;
int fd, rval;
if (r->instruction != r_input_direction)
return -1;
/* Get the filename. */
if (posixly_correct && !interactive_shell)
disallow_filename_globbing++;
fn = redirection_expand (r->redirectee.filename);
if (posixly_correct && !interactive_shell)
disallow_filename_globbing--;
if (fn == 0)
{
redirection_error (r, AMBIGUOUS_REDIRECT);
return -1;
}
fd = open(fn, O_RDONLY);
if (fd < 0)
{
file_error (fn);
free (fn);
return -1;
}
rval = zcatfd (fd, 1, fn);
free (fn);
close (fd);
return (rval);
}
int
evalstring (string, from_file, flags)
char *string;
const char *from_file;
int flags;
{
volatile int r, rflag, rcatch;
rcatch = 0;
rflag = return_catch_flag;
/* If we are in a place where `return' is valid, we have to catch
`eval "... return"' and make sure parse_and_execute cleans up. Then
we can trampoline to the previous saved return_catch location. */
if (rflag)
{
begin_unwind_frame ("evalstring");
unwind_protect_int (return_catch_flag);
unwind_protect_jmp_buf (return_catch);
return_catch_flag++; /* increment so we have a counter */
rcatch = setjmp_nosigs (return_catch);
}
if (rcatch)
{
parse_and_execute_cleanup ();
r = return_catch_value;
}
else
/* Note that parse_and_execute () frees the string it is passed. */
r = parse_and_execute (string, from_file, flags);
if (rflag)
{
run_unwind_frame ("evalstring");
if (rcatch && return_catch_flag)
{
return_catch_value = r;
sh_longjmp (return_catch, 1);
}
}
return (r);
}