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/* hashcmd.c - functions for managing a hash table mapping command names to
full pathnames. */
/* Copyright (C) 1997-2020 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>
#include "bashtypes.h"
#include "posixstat.h"
#if defined (HAVE_UNISTD_H)
# include <unistd.h>
#endif
#include "bashansi.h"
#include "shell.h"
#include "flags.h"
#include "findcmd.h"
#include "hashcmd.h"
HASH_TABLE *hashed_filenames = (HASH_TABLE *)NULL;
static void phash_freedata PARAMS((PTR_T));
void
phash_create ()
{
if (hashed_filenames == 0)
hashed_filenames = hash_create (FILENAME_HASH_BUCKETS);
}
static void
phash_freedata (data)
PTR_T data;
{
free (((PATH_DATA *)data)->path);
free (data);
}
void
phash_flush ()
{
if (hashed_filenames)
hash_flush (hashed_filenames, phash_freedata);
}
/* Remove FILENAME from the table of hashed commands. */
int
phash_remove (filename)
const char *filename;
{
register BUCKET_CONTENTS *item;
if (hashing_enabled == 0 || hashed_filenames == 0)
return 0;
item = hash_remove (filename, hashed_filenames, 0);
if (item)
{
if (item->data)
phash_freedata (item->data);
free (item->key);
free (item);
return 0;
}
return 1;
}
/* Place FILENAME (key) and FULL_PATH (data->path) into the
hash table. CHECK_DOT if non-null is for future calls to
phash_search (); it means that this file was found
in a directory in $PATH that is not an absolute pathname.
FOUND is the initial value for times_found. */
void
phash_insert (filename, full_path, check_dot, found)
char *filename, *full_path;
int check_dot, found;
{
register BUCKET_CONTENTS *item;
if (hashing_enabled == 0)
return;
if (hashed_filenames == 0)
phash_create ();
item = hash_insert (filename, hashed_filenames, 0);
if (item->data)
free (pathdata(item)->path);
else
{
item->key = savestring (filename);
item->data = xmalloc (sizeof (PATH_DATA));
}
pathdata(item)->path = savestring (full_path);
pathdata(item)->flags = 0;
if (check_dot)
pathdata(item)->flags |= HASH_CHKDOT;
if (*full_path != '/')
pathdata(item)->flags |= HASH_RELPATH;
item->times_found = found;
}
/* Return the full pathname that FILENAME hashes to. If FILENAME
is hashed, but (data->flags & HASH_CHKDOT) is non-zero, check
./FILENAME and return that if it is executable. This always
returns a newly-allocated string; the caller is responsible
for freeing it. */
char *
phash_search (filename)
const char *filename;
{
register BUCKET_CONTENTS *item;
char *path, *dotted_filename, *tail;
int same;
if (hashing_enabled == 0 || hashed_filenames == 0)
return ((char *)NULL);
item = hash_search (filename, hashed_filenames, 0);
if (item == NULL)
return ((char *)NULL);
/* If this filename is hashed, but `.' comes before it in the path,
see if ./filename is executable. If the hashed value is not an
absolute pathname, see if ./`hashed-value' exists. */
path = pathdata(item)->path;
if (pathdata(item)->flags & (HASH_CHKDOT|HASH_RELPATH))
{
tail = (pathdata(item)->flags & HASH_RELPATH) ? path : (char *)filename; /* XXX - fix const later */
/* If the pathname does not start with a `./', add a `./' to it. */
if (tail[0] != '.' || tail[1] != '/')
{
dotted_filename = (char *)xmalloc (3 + strlen (tail));
dotted_filename[0] = '.'; dotted_filename[1] = '/';
strcpy (dotted_filename + 2, tail);
}
else
dotted_filename = savestring (tail);
if (executable_file (dotted_filename))
return (dotted_filename);
free (dotted_filename);
#if 0
if (pathdata(item)->flags & HASH_RELPATH)
return ((char *)NULL);
#endif
/* Watch out. If this file was hashed to "./filename", and
"./filename" is not executable, then return NULL. */
/* Since we already know "./filename" is not executable, what
we're really interested in is whether or not the `path'
portion of the hashed filename is equivalent to the current
directory, but only if it starts with a `.'. (This catches
./. and so on.) same_file () tests general Unix file
equivalence -- same device and inode. */
if (*path == '.')
{
same = 0;
tail = (char *)strrchr (path, '/');
if (tail)
{
*tail = '\0';
same = same_file (".", path, (struct stat *)NULL, (struct stat *)NULL);
*tail = '/';
}
return same ? (char *)NULL : savestring (path);
}
}
return (savestring (path));
}
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