1 /* evalstring.c - evaluate a string as one or more shell commands. */
3 /* Copyright (C) 1996-2012 Free Software Foundation, Inc.
5 This file is part of GNU Bash, the Bourne Again SHell.
7 Bash is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Bash is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Bash. If not, see <http://www.gnu.org/licenses/>.
23 #if defined (HAVE_UNISTD_H)
25 # include <sys/types.h>
36 #include "../bashansi.h"
40 #include "../builtins.h"
43 #include "../execute_cmd.h"
46 #include "../bashintl.h"
51 # include "../bashhist.h"
61 #define IS_BUILTIN(s) (builtin_address_internal(s, 0) != (struct builtin *)NULL)
63 extern int indirection_level, subshell_environment;
64 extern int line_number, line_number_for_err_trap;
65 extern int current_token, shell_eof_token;
66 extern int last_command_exit_value;
67 extern int running_trap;
68 extern int loop_level;
69 extern int executing_list;
70 extern int comsub_ignore_return;
71 extern int posixly_correct;
72 extern int return_catch_flag, return_catch_value;
73 extern sh_builtin_func_t *this_shell_builtin;
74 extern char *the_printed_command_except_trap;
76 int parse_and_execute_level = 0;
78 static int cat_file __P((REDIRECT *));
80 #define PE_TAG "parse_and_execute top"
81 #define PS_TAG "parse_string top"
85 set_history_remembering ()
87 remember_on_history = enable_history_list;
95 FREE (the_printed_command_except_trap);
96 the_printed_command_except_trap = x;
99 /* How to force parse_and_execute () to clean up after itself. */
101 parse_and_execute_cleanup ()
105 run_trap_cleanup (running_trap - 1);
106 unfreeze_jobs_list ();
109 if (have_unwind_protects ())
110 run_unwind_frame (PE_TAG);
112 parse_and_execute_level = 0; /* XXX */
116 parse_prologue (string, flags, tag)
121 char *orig_string, *lastcom;
124 orig_string = string;
125 /* Unwind protect this invocation of parse_and_execute (). */
126 begin_unwind_frame (tag);
127 unwind_protect_int (parse_and_execute_level);
128 unwind_protect_jmp_buf (top_level);
129 unwind_protect_int (indirection_level);
130 unwind_protect_int (line_number);
131 unwind_protect_int (line_number_for_err_trap);
132 unwind_protect_int (loop_level);
133 unwind_protect_int (executing_list);
134 unwind_protect_int (comsub_ignore_return);
135 if (flags & (SEVAL_NONINT|SEVAL_INTERACT))
136 unwind_protect_int (interactive);
138 #if defined (HISTORY)
139 if (parse_and_execute_level == 0)
140 add_unwind_protect (set_history_remembering, (char *)NULL);
142 unwind_protect_int (remember_on_history); /* can be used in scripts */
143 # if defined (BANG_HISTORY)
144 if (interactive_shell)
145 unwind_protect_int (history_expansion_inhibited);
146 # endif /* BANG_HISTORY */
149 if (interactive_shell)
151 x = get_current_prompt_level ();
152 add_unwind_protect (set_current_prompt_level, x);
155 if (the_printed_command_except_trap)
157 lastcom = savestring (the_printed_command_except_trap);
158 add_unwind_protect (restore_lastcom, lastcom);
161 add_unwind_protect (pop_stream, (char *)NULL);
162 if (parser_expanding_alias ())
163 add_unwind_protect (parser_restore_alias, (char *)NULL);
165 if (orig_string && ((flags & SEVAL_NOFREE) == 0))
166 add_unwind_protect (xfree, orig_string);
169 if (flags & (SEVAL_NONINT|SEVAL_INTERACT))
170 interactive = (flags & SEVAL_NONINT) ? 0 : 1;
172 #if defined (HISTORY)
173 if (flags & SEVAL_NOHIST)
174 bash_history_disable ();
178 /* Parse and execute the commands in STRING. Returns whatever
179 execute_command () returns. This frees STRING. FLAGS is a
180 flags word; look in common.h for the possible values. Actions
182 (flags & SEVAL_NONINT) -> interactive = 0;
183 (flags & SEVAL_INTERACT) -> interactive = 1;
184 (flags & SEVAL_NOHIST) -> call bash_history_disable ()
185 (flags & SEVAL_NOFREE) -> don't free STRING when finished
186 (flags & SEVAL_RESETLINE) -> reset line_number to 1
190 parse_and_execute (string, from_file, flags)
192 const char *from_file;
196 volatile int should_jump_to_top_level, last_result;
197 COMMAND *volatile command;
198 volatile sigset_t pe_sigmask;
200 parse_prologue (string, flags, PE_TAG);
202 parse_and_execute_level++;
204 lreset = flags & SEVAL_RESETLINE;
206 #if defined (HAVE_POSIX_SIGNALS)
207 /* If we longjmp and are going to go on, use this to restore signal mask */
208 sigemptyset (&pe_sigmask);
209 sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &pe_sigmask);
212 /* Reset the line number if the caller wants us to. If we don't reset the
213 line number, we have to subtract one, because we will add one just
214 before executing the next command (resetting the line number sets it to
215 0; the first line number is 1). */
216 push_stream (lreset);
217 if (parser_expanding_alias ())
218 /* push current shell_input_line */
219 parser_save_alias ();
226 code = should_jump_to_top_level = 0;
227 last_result = EXECUTION_SUCCESS;
229 with_input_from_string (string, from_file);
230 while (*(bash_input.location.string))
232 command = (COMMAND *)NULL;
236 last_result = EXECUTION_FAILURE;
240 /* Provide a location for functions which `longjmp (top_level)' to
241 jump to. This prevents errors in substitution from restarting
242 the reader loop directly, for example. */
243 code = setjmp_nosigs (top_level);
247 should_jump_to_top_level = 0;
251 /* variable_context -> 0 is what eval.c:reader_loop() does in
252 these circumstances. Don't bother with cleanup here because
253 we don't want to run the function execution cleanup stuff
254 that will cause pop_context and other functions to run.
255 XXX - change that if we want the function context to be
257 if (exit_immediately_on_error && variable_context)
259 discard_unwind_frame ("pe_dispose");
260 variable_context = 0; /* not in a function */
262 should_jump_to_top_level = 1;
267 run_unwind_frame ("pe_dispose");
268 /* Remember to call longjmp (top_level) after the old
269 value for it is restored. */
270 should_jump_to_top_level = 1;
275 run_unwind_frame ("pe_dispose");
276 last_result = last_command_exit_value = EXECUTION_FAILURE; /* XXX */
277 if (subshell_environment)
279 should_jump_to_top_level = 1;
285 dispose_command (command); /* pe_dispose does this */
287 #if defined (HAVE_POSIX_SIGNALS)
288 sigprocmask (SIG_SETMASK, &pe_sigmask, (sigset_t *)NULL);
294 command_error ("parse_and_execute", CMDERR_BADJUMP, code, 0);
299 if (parse_command () == 0)
301 if ((flags & SEVAL_PARSEONLY) || (interactive_shell == 0 && read_but_dont_execute))
303 last_result = EXECUTION_SUCCESS;
304 dispose_command (global_command);
305 global_command = (COMMAND *)NULL;
307 else if (command = global_command)
309 struct fd_bitmap *bitmap;
311 bitmap = new_fd_bitmap (FD_BITMAP_SIZE);
312 begin_unwind_frame ("pe_dispose");
313 add_unwind_protect (dispose_fd_bitmap, bitmap);
314 add_unwind_protect (dispose_command, command); /* XXX */
316 global_command = (COMMAND *)NULL;
318 if ((subshell_environment & SUBSHELL_COMSUB) && comsub_ignore_return)
319 command->flags |= CMD_IGNORE_RETURN;
321 #if defined (ONESHOT)
324 * we were invoked as `bash -c' (startup_state == 2) AND
325 * parse_and_execute has not been called recursively AND
326 * we're not running a trap AND
327 * we have parsed the full command (string == '\0') AND
328 * we're not going to run the exit trap AND
329 * we have a simple command without redirections AND
330 * the command is not being timed AND
331 * the command's return status is not being inverted
333 * tell the execution code that we don't need to fork
335 if (startup_state == 2 && parse_and_execute_level == 1 &&
337 *bash_input.location.string == '\0' &&
338 command->type == cm_simple &&
339 signal_is_trapped (EXIT_TRAP) == 0 &&
340 command->redirects == 0 && command->value.Simple->redirects == 0 &&
341 ((command->flags & CMD_TIME_PIPELINE) == 0) &&
342 ((command->flags & CMD_INVERT_RETURN) == 0))
344 command->flags |= CMD_NO_FORK;
345 command->value.Simple->flags |= CMD_NO_FORK;
349 /* See if this is a candidate for $( <file ). */
350 if (startup_state == 2 &&
351 (subshell_environment & SUBSHELL_COMSUB) &&
352 *bash_input.location.string == '\0' &&
353 command->type == cm_simple && !command->redirects &&
354 (command->flags & CMD_TIME_PIPELINE) == 0 &&
355 command->value.Simple->words == 0 &&
356 command->value.Simple->redirects &&
357 command->value.Simple->redirects->next == 0 &&
358 command->value.Simple->redirects->instruction == r_input_direction &&
359 command->value.Simple->redirects->redirector.dest == 0)
362 r = cat_file (command->value.Simple->redirects);
363 last_result = (r < 0) ? EXECUTION_FAILURE : EXECUTION_SUCCESS;
366 last_result = execute_command_internal
367 (command, 0, NO_PIPE, NO_PIPE, bitmap);
368 dispose_command (command);
369 dispose_fd_bitmap (bitmap);
370 discard_unwind_frame ("pe_dispose");
375 last_result = EXECUTION_FAILURE;
377 if (interactive_shell == 0 && this_shell_builtin &&
378 (this_shell_builtin == source_builtin || this_shell_builtin == eval_builtin) &&
379 last_command_exit_value == EX_BADSYNTAX && posixly_correct)
381 should_jump_to_top_level = 1;
383 last_command_exit_value = EX_BADUSAGE;
386 /* Since we are shell compatible, syntax errors in a script
387 abort the execution of the script. Right? */
394 run_unwind_frame (PE_TAG);
396 if (interrupt_state && parse_and_execute_level == 0)
398 /* An interrupt during non-interactive execution in an
399 interactive shell (e.g. via $PROMPT_COMMAND) should
400 not cause the shell to exit. */
401 interactive = interactive_shell;
402 throw_to_top_level ();
405 if (should_jump_to_top_level)
406 jump_to_top_level (code);
408 return (last_result);
411 /* Parse a command contained in STRING according to FLAGS and return the
412 number of characters consumed from the string. If non-NULL, set *ENDP
413 to the position in the string where the parse ended. Used to validate
414 command substitutions during parsing to obey Posix rules about finding
415 the end of the command and balancing parens. */
417 parse_string (string, from_file, flags, endp)
419 const char *from_file;
424 volatile int should_jump_to_top_level;
425 COMMAND *volatile command, *oglobal;
427 volatile sigset_t ps_sigmask;
429 parse_prologue (string, flags, PS_TAG);
431 #if defined (HAVE_POSIX_SIGNALS)
432 /* If we longjmp and are going to go on, use this to restore signal mask */
433 sigemptyset (&ps_sigmask);
434 sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &ps_sigmask);
437 /* itrace("parse_string: `%s'", string); */
438 /* Reset the line number if the caller wants us to. If we don't reset the
439 line number, we have to subtract one, because we will add one just
440 before executing the next command (resetting the line number sets it to
441 0; the first line number is 1). */
443 if (parser_expanding_alias ())
444 /* push current shell_input_line */
445 parser_save_alias ();
447 code = should_jump_to_top_level = 0;
448 oglobal = global_command;
451 with_input_from_string (string, from_file);
452 while (*(bash_input.location.string))
454 command = (COMMAND *)NULL;
461 /* Provide a location for functions which `longjmp (top_level)' to
463 code = setjmp_nosigs (top_level);
468 itrace("parse_string: longjmp executed: code = %d", code);
470 should_jump_to_top_level = 0;
476 case DISCARD: /* XXX */
478 dispose_command (command);
479 /* Remember to call longjmp (top_level) after the old
480 value for it is restored. */
481 should_jump_to_top_level = 1;
485 #if defined (HAVE_POSIX_SIGNALS)
486 sigprocmask (SIG_SETMASK, &ps_sigmask, (sigset_t *)NULL);
488 command_error ("parse_string", CMDERR_BADJUMP, code, 0);
493 if (parse_command () == 0)
495 dispose_command (global_command);
496 global_command = (COMMAND *)NULL;
500 if ((flags & SEVAL_NOLONGJMP) == 0)
502 should_jump_to_top_level = 1;
506 reset_parser (); /* XXX - sets token_to_read */
510 if (current_token == yacc_EOF || current_token == shell_eof_token)
516 global_command = oglobal;
517 nc = bash_input.location.string - ostring;
519 *endp = bash_input.location.string;
521 run_unwind_frame (PS_TAG);
523 if (should_jump_to_top_level)
524 jump_to_top_level (code);
529 /* Handle a $( < file ) command substitution. This expands the filename,
530 returning errors as appropriate, then just cats the file to the standard
539 if (r->instruction != r_input_direction)
542 /* Get the filename. */
543 if (posixly_correct && !interactive_shell)
544 disallow_filename_globbing++;
545 fn = redirection_expand (r->redirectee.filename);
546 if (posixly_correct && !interactive_shell)
547 disallow_filename_globbing--;
551 redirection_error (r, AMBIGUOUS_REDIRECT);
555 fd = open(fn, O_RDONLY);
563 rval = zcatfd (fd, 1, fn);
572 evalstring (string, from_file, flags)
574 const char *from_file;
577 volatile int r, rflag, rcatch;
580 rflag = return_catch_flag;
581 /* If we are in a place where `return' is valid, we have to catch
582 `eval "... return"' and make sure parse_and_execute cleans up. Then
583 we can trampoline to the previous saved return_catch location. */
586 begin_unwind_frame ("evalstring");
588 unwind_protect_int (return_catch_flag);
589 unwind_protect_jmp_buf (return_catch);
591 return_catch_flag++; /* increment so we have a counter */
592 rcatch = setjmp_nosigs (return_catch);
597 parse_and_execute_cleanup ();
598 r = return_catch_value;
601 /* Note that parse_and_execute () frees the string it is passed. */
602 r = parse_and_execute (string, from_file, flags);
606 run_unwind_frame ("evalstring");
607 if (rcatch && return_catch_flag)
609 return_catch_value = r;
610 longjmp (return_catch, 1);