| [3228] | 1 | /* I can't stand it anymore! Please can't we just write the
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| 2 | whole Unix system in lisp or something? */
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| 3 |
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| 4 | /* Copyright (C) 1987-2002 Free Software Foundation, Inc.
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| 5 |
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| 6 | This file is part of GNU Bash, the Bourne Again SHell.
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| 7 |
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| 8 | Bash is free software; you can redistribute it and/or modify it under
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| 9 | the terms of the GNU General Public License as published by the Free
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| 10 | Software Foundation; either version 2, or (at your option) any later
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| 11 | version.
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| 12 |
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| 13 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY
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| 14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or
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| 15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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| 16 | for more details.
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| 17 |
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| 18 | You should have received a copy of the GNU General Public License along
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| 19 | with Bash; see the file COPYING. If not, write to the Free Software
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| 20 | Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
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| 21 |
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| 22 | /* **************************************************************** */
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| 23 | /* */
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| 24 | /* Unwind Protection Scheme for Bash */
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| 25 | /* */
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| 26 | /* **************************************************************** */
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| 27 | #include "config.h"
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| 28 |
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| 29 | #include "bashtypes.h"
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| 30 | #include "bashansi.h"
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| 31 |
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| 32 | #if defined (HAVE_UNISTD_H)
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| 33 | # include <unistd.h>
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| 34 | #endif
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| 35 |
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| 36 | #if STDC_HEADERS
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| 37 | # include <stddef.h>
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| 38 | #endif
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| 39 |
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| 40 | #ifndef offsetof
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| 41 | # define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
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| 42 | #endif
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| 43 |
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| 44 | #include "command.h"
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| 45 | #include "general.h"
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| 46 | #include "unwind_prot.h"
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| 47 | #include "quit.h"
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| 48 | #include "sig.h"
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| 49 |
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| 50 | /* Structure describing a saved variable and the value to restore it to. */
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| 51 | typedef struct {
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| 52 | char *variable;
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| 53 | int size;
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| 54 | char desired_setting[1]; /* actual size is `size' */
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| 55 | } SAVED_VAR;
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| 56 |
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| 57 | /* If HEAD.CLEANUP is null, then ARG.V contains a tag to throw back to.
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| 58 | If HEAD.CLEANUP is restore_variable, then SV.V contains the saved
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| 59 | variable. Otherwise, call HEAD.CLEANUP (ARG.V) to clean up. */
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| 60 | typedef union uwp {
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| 61 | struct uwp_head {
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| 62 | union uwp *next;
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| 63 | Function *cleanup;
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| 64 | } head;
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| 65 | struct {
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| 66 | struct uwp_head uwp_head;
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| 67 | char *v;
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| 68 | } arg;
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| 69 | struct {
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| 70 | struct uwp_head uwp_head;
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| 71 | SAVED_VAR v;
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| 72 | } sv;
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| 73 | } UNWIND_ELT;
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| 74 |
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| 75 |
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| 76 | extern int interrupt_immediately;
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| 77 |
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| 78 | static void without_interrupts __P((VFunction *, char *, char *));
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| 79 | static void unwind_frame_discard_internal __P((char *, char *));
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| 80 | static void unwind_frame_run_internal __P((char *, char *));
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| 81 | static void add_unwind_protect_internal __P((Function *, char *));
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| 82 | static void remove_unwind_protect_internal __P((char *, char *));
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| 83 | static void run_unwind_protects_internal __P((char *, char *));
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| 84 | static void clear_unwind_protects_internal __P((char *, char *));
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| 85 | static inline void restore_variable __P((SAVED_VAR *));
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| 86 | static void unwind_protect_mem_internal __P((char *, char *));
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| 87 |
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| 88 | static UNWIND_ELT *unwind_protect_list = (UNWIND_ELT *)NULL;
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| 89 |
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| 90 | #define uwpalloc(elt) (elt) = (UNWIND_ELT *)xmalloc (sizeof (UNWIND_ELT))
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| 91 | #define uwpfree(elt) free(elt)
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| 92 |
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| 93 | /* Run a function without interrupts. This relies on the fact that the
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| 94 | FUNCTION cannot change the value of interrupt_immediately. (I.e., does
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| 95 | not call QUIT (). */
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| 96 | static void
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| 97 | without_interrupts (function, arg1, arg2)
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| 98 | VFunction *function;
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| 99 | char *arg1, *arg2;
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| 100 | {
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| 101 | int old_interrupt_immediately;
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| 102 |
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| 103 | old_interrupt_immediately = interrupt_immediately;
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| 104 | interrupt_immediately = 0;
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| 105 |
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| 106 | (*function)(arg1, arg2);
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| 107 |
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| 108 | interrupt_immediately = old_interrupt_immediately;
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| 109 | }
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| 110 |
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| 111 | /* Start the beginning of a region. */
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| 112 | void
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| 113 | begin_unwind_frame (tag)
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| 114 | char *tag;
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| 115 | {
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| 116 | add_unwind_protect ((Function *)NULL, tag);
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| 117 | }
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| 118 |
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| 119 | /* Discard the unwind protects back to TAG. */
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| 120 | void
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| 121 | discard_unwind_frame (tag)
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| 122 | char *tag;
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| 123 | {
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| 124 | if (unwind_protect_list)
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| 125 | without_interrupts (unwind_frame_discard_internal, tag, (char *)NULL);
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| 126 | }
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| 127 |
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| 128 | /* Run the unwind protects back to TAG. */
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| 129 | void
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| 130 | run_unwind_frame (tag)
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| 131 | char *tag;
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| 132 | {
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| 133 | if (unwind_protect_list)
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| 134 | without_interrupts (unwind_frame_run_internal, tag, (char *)NULL);
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| 135 | }
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| 136 |
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| 137 | /* Add the function CLEANUP with ARG to the list of unwindable things. */
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| 138 | void
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| 139 | add_unwind_protect (cleanup, arg)
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| 140 | Function *cleanup;
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