mirror of https://github.com/n-hys/bash.git
494 lines
13 KiB
C
494 lines
13 KiB
C
/* tilde.c -- Tilde expansion code (~/foo := $HOME/foo). */
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/* Copyright (C) 1988-2020 Free Software Foundation, Inc.
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This file is part of the GNU Readline Library (Readline), a library
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for reading lines of text with interactive input and history editing.
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Readline 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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Readline 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 Readline. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if defined (HAVE_CONFIG_H)
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# include <config.h>
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#endif
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#if defined (HAVE_UNISTD_H)
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# ifdef _MINIX
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# include <sys/types.h>
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# endif
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# include <unistd.h>
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#endif
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#if defined (HAVE_STRING_H)
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# include <string.h>
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#else /* !HAVE_STRING_H */
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# include <strings.h>
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#endif /* !HAVE_STRING_H */
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#if defined (HAVE_STDLIB_H)
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# include <stdlib.h>
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#else
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# include "ansi_stdlib.h"
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#endif /* HAVE_STDLIB_H */
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#include <sys/types.h>
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#if defined (HAVE_PWD_H)
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#include <pwd.h>
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#endif
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#include "tilde.h"
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#if defined (TEST) || defined (STATIC_MALLOC)
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static void *xmalloc (), *xrealloc ();
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#else
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# include "xmalloc.h"
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#endif /* TEST || STATIC_MALLOC */
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#if !defined (HAVE_GETPW_DECLS)
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# if defined (HAVE_GETPWUID)
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extern struct passwd *getpwuid (uid_t);
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# endif
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# if defined (HAVE_GETPWNAM)
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extern struct passwd *getpwnam (const char *);
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# endif
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#endif /* !HAVE_GETPW_DECLS */
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#if !defined (savestring)
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#define savestring(x) strcpy ((char *)xmalloc (1 + strlen (x)), (x))
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#endif /* !savestring */
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#if !defined (NULL)
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# if defined (__STDC__)
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# define NULL ((void *) 0)
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# else
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# define NULL 0x0
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# endif /* !__STDC__ */
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#endif /* !NULL */
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/* If being compiled as part of bash, these will be satisfied from
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variables.o. If being compiled as part of readline, they will
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be satisfied from shell.o. */
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extern char *sh_get_home_dir (void);
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extern char *sh_get_env_value (const char *);
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/* The default value of tilde_additional_prefixes. This is set to
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whitespace preceding a tilde so that simple programs which do not
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perform any word separation get desired behaviour. */
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static const char *default_prefixes[] =
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{ " ~", "\t~", (const char *)NULL };
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/* The default value of tilde_additional_suffixes. This is set to
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whitespace or newline so that simple programs which do not
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perform any word separation get desired behaviour. */
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static const char *default_suffixes[] =
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{ " ", "\n", (const char *)NULL };
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/* If non-null, this contains the address of a function that the application
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wants called before trying the standard tilde expansions. The function
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is called with the text sans tilde, and returns a malloc()'ed string
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which is the expansion, or a NULL pointer if the expansion fails. */
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tilde_hook_func_t *tilde_expansion_preexpansion_hook = (tilde_hook_func_t *)NULL;
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/* If non-null, this contains the address of a function to call if the
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standard meaning for expanding a tilde fails. The function is called
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with the text (sans tilde, as in "foo"), and returns a malloc()'ed string
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which is the expansion, or a NULL pointer if there is no expansion. */
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tilde_hook_func_t *tilde_expansion_failure_hook = (tilde_hook_func_t *)NULL;
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/* When non-null, this is a NULL terminated array of strings which
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are duplicates for a tilde prefix. Bash uses this to expand
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`=~' and `:~'. */
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char **tilde_additional_prefixes = (char **)default_prefixes;
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/* When non-null, this is a NULL terminated array of strings which match
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the end of a username, instead of just "/". Bash sets this to
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`:' and `=~'. */
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char **tilde_additional_suffixes = (char **)default_suffixes;
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static int tilde_find_prefix (const char *, int *);
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static int tilde_find_suffix (const char *);
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static char *isolate_tilde_prefix (const char *, int *);
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static char *glue_prefix_and_suffix (char *, const char *, int);
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/* Find the start of a tilde expansion in STRING, and return the index of
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the tilde which starts the expansion. Place the length of the text
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which identified this tilde starter in LEN, excluding the tilde itself. */
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static int
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tilde_find_prefix (const char *string, int *len)
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{
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register int i, j, string_len;
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register char **prefixes;
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prefixes = tilde_additional_prefixes;
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string_len = strlen (string);
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*len = 0;
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if (*string == '\0' || *string == '~')
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return (0);
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if (prefixes)
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{
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for (i = 0; i < string_len; i++)
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{
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for (j = 0; prefixes[j]; j++)
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{
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if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
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{
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*len = strlen (prefixes[j]) - 1;
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return (i + *len);
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}
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}
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}
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}
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return (string_len);
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}
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/* Find the end of a tilde expansion in STRING, and return the index of
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the character which ends the tilde definition. */
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static int
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tilde_find_suffix (const char *string)
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{
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register int i, j, string_len;
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register char **suffixes;
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suffixes = tilde_additional_suffixes;
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string_len = strlen (string);
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for (i = 0; i < string_len; i++)
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{
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#if defined (__MSDOS__)
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if (string[i] == '/' || string[i] == '\\' /* || !string[i] */)
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#else
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if (string[i] == '/' /* || !string[i] */)
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#endif
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break;
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for (j = 0; suffixes && suffixes[j]; j++)
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{
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if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
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return (i);
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}
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}
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return (i);
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}
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/* Return a new string which is the result of tilde expanding STRING. */
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char *
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tilde_expand (const char *string)
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{
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char *result;
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int result_size, result_index;
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result_index = result_size = 0;
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if (result = strchr (string, '~'))
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result = (char *)xmalloc (result_size = (strlen (string) + 16));
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else
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result = (char *)xmalloc (result_size = (strlen (string) + 1));
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/* Scan through STRING expanding tildes as we come to them. */
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while (1)
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{
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register int start, end;
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char *tilde_word, *expansion;
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int len;
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/* Make START point to the tilde which starts the expansion. */
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start = tilde_find_prefix (string, &len);
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/* Copy the skipped text into the result. */
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if ((result_index + start + 1) > result_size)
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result = (char *)xrealloc (result, 1 + (result_size += (start + 20)));
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strncpy (result + result_index, string, start);
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result_index += start;
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/* Advance STRING to the starting tilde. */
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string += start;
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/* Make END be the index of one after the last character of the
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username. */
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end = tilde_find_suffix (string);
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/* If both START and END are zero, we are all done. */
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if (!start && !end)
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break;
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/* Expand the entire tilde word, and copy it into RESULT. */
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tilde_word = (char *)xmalloc (1 + end);
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strncpy (tilde_word, string, end);
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tilde_word[end] = '\0';
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string += end;
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expansion = tilde_expand_word (tilde_word);
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if (expansion == 0)
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expansion = tilde_word;
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else
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xfree (tilde_word);
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len = strlen (expansion);
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#ifdef __CYGWIN__
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/* Fix for Cygwin to prevent ~user/xxx from expanding to //xxx when
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$HOME for `user' is /. On cygwin, // denotes a network drive. */
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if (len > 1 || *expansion != '/' || *string != '/')
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#endif
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{
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if ((result_index + len + 1) > result_size)
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result = (char *)xrealloc (result, 1 + (result_size += (len + 20)));
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strcpy (result + result_index, expansion);
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result_index += len;
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}
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xfree (expansion);
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}
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result[result_index] = '\0';
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return (result);
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}
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/* Take FNAME and return the tilde prefix we want expanded. If LENP is
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non-null, the index of the end of the prefix into FNAME is returned in
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the location it points to. */
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static char *
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isolate_tilde_prefix (const char *fname, int *lenp)
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{
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char *ret;
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int i;
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ret = (char *)xmalloc (strlen (fname));
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#if defined (__MSDOS__)
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for (i = 1; fname[i] && fname[i] != '/' && fname[i] != '\\'; i++)
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#else
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for (i = 1; fname[i] && fname[i] != '/'; i++)
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#endif
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ret[i - 1] = fname[i];
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ret[i - 1] = '\0';
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if (lenp)
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*lenp = i;
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return ret;
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}
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#if 0
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/* Public function to scan a string (FNAME) beginning with a tilde and find
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the portion of the string that should be passed to the tilde expansion
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function. Right now, it just calls tilde_find_suffix and allocates new
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memory, but it can be expanded to do different things later. */
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char *
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tilde_find_word (const char *fname, int flags, int *lenp)
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{
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int x;
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char *r;
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x = tilde_find_suffix (fname);
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if (x == 0)
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{
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r = savestring (fname);
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if (lenp)
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*lenp = 0;
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}
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else
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{
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r = (char *)xmalloc (1 + x);
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strncpy (r, fname, x);
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r[x] = '\0';
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if (lenp)
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*lenp = x;
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}
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return r;
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}
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#endif
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/* Return a string that is PREFIX concatenated with SUFFIX starting at
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SUFFIND. */
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static char *
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glue_prefix_and_suffix (char *prefix, const char *suffix, int suffind)
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{
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char *ret;
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int plen, slen;
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plen = (prefix && *prefix) ? strlen (prefix) : 0;
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slen = strlen (suffix + suffind);
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ret = (char *)xmalloc (plen + slen + 1);
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if (plen)
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strcpy (ret, prefix);
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strcpy (ret + plen, suffix + suffind);
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return ret;
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}
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/* Do the work of tilde expansion on FILENAME. FILENAME starts with a
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tilde. If there is no expansion, call tilde_expansion_failure_hook.
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This always returns a newly-allocated string, never static storage. */
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char *
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tilde_expand_word (const char *filename)
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{
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char *dirname, *expansion, *username;
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int user_len;
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struct passwd *user_entry;
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if (filename == 0)
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return ((char *)NULL);
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if (*filename != '~')
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return (savestring (filename));
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/* A leading `~/' or a bare `~' is *always* translated to the value of
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$HOME or the home directory of the current user, regardless of any
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preexpansion hook. */
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if (filename[1] == '\0' || filename[1] == '/')
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{
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/* Prefix $HOME to the rest of the string. */
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expansion = sh_get_env_value ("HOME");
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#if defined (_WIN32)
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if (expansion == 0)
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expansion = sh_get_env_value ("APPDATA");
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#endif
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/* If there is no HOME variable, look up the directory in
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the password database. */
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if (expansion == 0)
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expansion = sh_get_home_dir ();
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return (glue_prefix_and_suffix (expansion, filename, 1));
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}
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username = isolate_tilde_prefix (filename, &user_len);
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if (tilde_expansion_preexpansion_hook)
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{
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expansion = (*tilde_expansion_preexpansion_hook) (username);
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if (expansion)
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{
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dirname = glue_prefix_and_suffix (expansion, filename, user_len);
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xfree (username);
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xfree (expansion);
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return (dirname);
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}
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}
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/* No preexpansion hook, or the preexpansion hook failed. Look in the
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password database. */
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dirname = (char *)NULL;
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#if defined (HAVE_GETPWNAM)
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user_entry = getpwnam (username);
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#else
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user_entry = 0;
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#endif
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if (user_entry == 0)
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{
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/* If the calling program has a special syntax for expanding tildes,
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and we couldn't find a standard expansion, then let them try. */
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if (tilde_expansion_failure_hook)
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{
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expansion = (*tilde_expansion_failure_hook) (username);
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if (expansion)
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{
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dirname = glue_prefix_and_suffix (expansion, filename, user_len);
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xfree (expansion);
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}
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}
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/* If we don't have a failure hook, or if the failure hook did not
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expand the tilde, return a copy of what we were passed. */
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if (dirname == 0)
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dirname = savestring (filename);
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}
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#if defined (HAVE_GETPWENT)
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else
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dirname = glue_prefix_and_suffix (user_entry->pw_dir, filename, user_len);
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#endif
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xfree (username);
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#if defined (HAVE_GETPWENT)
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endpwent ();
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#endif
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return (dirname);
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}
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#if defined (TEST)
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#undef NULL
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#include <stdio.h>
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main (int argc, char **argv)
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{
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char *result, line[512];
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int done = 0;
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while (!done)
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{
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printf ("~expand: ");
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fflush (stdout);
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if (!gets (line))
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strcpy (line, "done");
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if ((strcmp (line, "done") == 0) ||
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(strcmp (line, "quit") == 0) ||
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(strcmp (line, "exit") == 0))
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{
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done = 1;
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break;
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}
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result = tilde_expand (line);
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printf (" --> %s\n", result);
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free (result);
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}
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exit (0);
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}
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static void memory_error_and_abort (void);
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static void *
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xmalloc (size_t bytes)
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{
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void *temp = (char *)malloc (bytes);
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if (!temp)
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memory_error_and_abort ();
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return (temp);
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}
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static void *
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xrealloc (void *pointer, int bytes)
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{
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void *temp;
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if (!pointer)
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temp = malloc (bytes);
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else
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temp = realloc (pointer, bytes);
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if (!temp)
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memory_error_and_abort ();
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return (temp);
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}
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static void
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memory_error_and_abort (void)
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{
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fprintf (stderr, "readline: out of virtual memory\n");
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abort ();
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}
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/*
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* Local variables:
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* compile-command: "gcc -g -DTEST -o tilde tilde.c"
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* end:
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*/
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#endif /* TEST */
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