/* tilde.c -- tilde expansion code (~/foo := $HOME/foo).
$Id: tilde.c,v 1.10 2012/11/16 23:33:29 karl Exp $
Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1996, 1998, 1999,
2002, 2004, 2006, 2007, 2008, 2012 Free Software Foundation, Inc.
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
Written by Brian Fox (bfox@ai.mit.edu). */
#include "info.h"
#include "tilde.h"
#if defined (TEST) || defined (STATIC_MALLOC)
static void *xmalloc (), *xrealloc ();
#endif /* TEST || STATIC_MALLOC */
/* The default value of tilde_additional_prefixes. This is set to
whitespace preceding a tilde so that simple programs which do not
perform any word separation get desired behaviour. */
static char *default_prefixes[] =
{ " ~", "\t~", NULL };
/* The default value of tilde_additional_suffixes. This is set to
whitespace or newline so that simple programs which do not
perform any word separation get desired behaviour. */
static char *default_suffixes[] =
{ " ", "\n", NULL };
/* If non-null, this contains the address of a function to call if the
standard meaning for expanding a tilde fails. The function is called
with the text (sans tilde, as in "foo"), and returns a malloc()'ed string
which is the expansion, or a NULL pointer if there is no expansion. */
CFunction *tilde_expansion_failure_hook = NULL;
/* When non-null, this is a NULL terminated array of strings which
are duplicates for a tilde prefix. Bash uses this to expand
`=~' and `:~'. */
char **tilde_additional_prefixes = default_prefixes;
/* When non-null, this is a NULL terminated array of strings which match
the end of a username, instead of just "/". Bash sets this to
`:' and `=~'. */
char **tilde_additional_suffixes = default_suffixes;
/* Find the start of a tilde expansion in STRING, and return the index of
the tilde which starts the expansion. Place the length of the text
which identified this tilde starter in LEN, excluding the tilde itself. */
static int
tilde_find_prefix (char *string, int *len)
{
register int i, j, string_len;
register char **prefixes = tilde_additional_prefixes;
string_len = strlen (string);
*len = 0;
if (!*string || *string == '~')
return 0;
if (prefixes)
{
for (i = 0; i < string_len; i++)
{
for (j = 0; prefixes[j]; j++)
{
if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
{
*len = strlen (prefixes[j]) - 1;
return i + *len;
}
}
}
}
return string_len;
}
/* Find the end of a tilde expansion in STRING, and return the index of
the character which ends the tilde definition. */
static int
tilde_find_suffix (char *string)
{
register int i, j, string_len;
register char **suffixes = tilde_additional_suffixes;
string_len = strlen (string);
for (i = 0; i < string_len; i++)
{
if (IS_SLASH (string[i]) || !string[i])
break;
for (j = 0; suffixes && suffixes[j]; j++)
{
if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
return i;
}
}
return i;
}
/* Return a new string which is the result of tilde expanding STRING. */
char *
tilde_expand (char *string)
{
char *result;
int result_size, result_index;
result_size = result_index = 0;
result = NULL;
/* Scan through STRING expanding tildes as we come to them. */
while (1)
{
register int start, end;
char *tilde_word, *expansion;
int len;
/* Make START point to the tilde which starts the expansion. */
start = tilde_find_prefix (string, &len);
/* Copy the skipped text into the result. */
if ((result_index + start + 1) > result_size)
result = xrealloc (result, 1 + (result_size += (start + 20)));
strncpy (result + result_index, string, start);
result_index += start;
/* Advance STRING to the starting tilde. */
string += start;
/* Make END be the index of one after the last character of the
username. */
end = tilde_find_suffix (string);
/* If both START and END are zero, we are all done. */
if (!start && !end)
break;
/* Expand the entire tilde word, and copy it into RESULT. */
tilde_word = xmalloc (1 + end);
strncpy (tilde_word, string, end);
tilde_word[end] = '\0';
string += end;
expansion = tilde_expand_word (tilde_word);
free (tilde_word);
len = strlen (expansion);
if ((result_index + len + 1) > result_size)
result = xrealloc (result, 1 + (result_size += (len + 20)));
strcpy (result + result_index, expansion);
result_index += len;
free (expansion);
}
result[result_index] = '\0';
return result;
}
/* Do the work of tilde expansion on FILENAME. FILENAME starts with a
tilde. If there is no expansion, call tilde_expansion_failure_hook. */
char *
tilde_expand_word (char *filename)
{
char *dirname = filename ? xstrdup (filename) : NULL;
if (dirname && *dirname == '~')
{
char *temp_name;
if (!dirname[1] || IS_SLASH (dirname[1]))
{
/* Prepend $HOME to the rest of the string. */
char *temp_home = getenv ("HOME");
/* If there is no HOME variable, look up the directory in
the password database. */
if (!temp_home)
{
#ifndef __MINGW32__
struct passwd *entry;
entry = (struct passwd *) getpwuid (getuid ());
if (entry)
temp_home = entry->pw_dir;
#else
temp_home = ".";
#endif
}
temp_name = xmalloc (1 + strlen (&dirname[1])
+ (temp_home ? strlen (temp_home) : 0));
if (temp_home)
strcpy (temp_name, temp_home);
else
temp_name[0] = 0;
strcat (temp_name, &dirname[1]);
free (dirname);
dirname = xstrdup (temp_name);
free (temp_name);
}
else
{
#ifndef __MINGW32__
struct passwd *user_entry;
#endif
char *username = xmalloc (257);
int i, c;
for (i = 1; (c = dirname[i]); i++)
{
if (IS_SLASH (c))
break;
else
username[i - 1] = c;
}
username[i - 1] = 0;
#ifndef __MINGW32__
if (!(user_entry = (struct passwd *) getpwnam (username)))
{
/* If the calling program has a special syntax for
expanding tildes, and we couldn't find a standard
expansion, then let them try. */
if (tilde_expansion_failure_hook)
{
char *expansion = (*tilde_expansion_failure_hook) (username);
if (expansion)
{
temp_name = xmalloc (1 + strlen (expansion)
+ strlen (&dirname[i]));
strcpy (temp_name, expansion);
strcat (temp_name, &dirname[i]);
free (expansion);
goto return_name;
}
}
/* We shouldn't report errors. */
}
else
{
temp_name = xmalloc (1 + strlen (user_entry->pw_dir)
+ strlen (&dirname[i]));
strcpy (temp_name, user_entry->pw_dir);
strcat (temp_name, &dirname[i]);
return_name:
free (dirname);
dirname = xstrdup (temp_name);
free (temp_name);
}
endpwent ();
free (username);
#else
if (tilde_expansion_failure_hook)
{
char *expansion = (*tilde_expansion_failure_hook) (username);
if (expansion)
{
temp_name = xmalloc (1 + strlen (expansion)
+ strlen (&dirname[i]));
strcpy (temp_name, expansion);
strcat (temp_name, &dirname[i]);
free (expansion);
}
}
free (dirname);
dirname = xstrdup (temp_name);
free (temp_name);
#endif
}
}
return dirname;
}
#if defined (TEST)
#undef NULL
#include <stdio.h>
main (argc, argv)
int argc;
char **argv;
{
char *result, line[512];
int done = 0;
while (!done)
{
printf ("~expand: ");
fflush (stdout);
if (!gets (line))
strcpy (line, "done");
if ((strcmp (line, "done") == 0) ||
(strcmp (line, "quit") == 0) ||
(strcmp (line, "exit") == 0))
{
done = 1;
break;
}
result = tilde_expand (line);
printf (" --> %s\n", result);
free (result);
}
exit (EXIT_SUCCESS);
}
static void memory_error_and_abort ();
static void *
xmalloc (bytes)
int bytes;
{
void *temp = (void *)malloc (bytes);
if (!temp)
memory_error_and_abort ();
return temp;
}
static void *
xrealloc (pointer, bytes)
void *pointer;
int bytes;
{
void *temp;
if (!pointer)
temp = (char *)malloc (bytes);
else
temp = (char *)realloc (pointer, bytes);
if (!temp)
memory_error_and_abort ();
return temp;
}
static void
memory_error_and_abort ()
{
fprintf (stderr, _("readline: Out of virtual memory!\n"));
abort ();
}
#endif /* TEST */