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1 | /* hashcmd.c - functions for managing a hash table mapping command names to |
2 | full pathnames. */ | |
3 | ||
4 | /* Copyright (C) 1997 Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GNU Bash, the Bourne Again SHell. | |
7 | ||
8 | Bash is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 1, or (at your option) any later | |
11 | version. | |
12 | ||
13 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License along | |
19 | with Bash; see the file COPYING. If not, write to the Free Software | |
20 | Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
21 | ||
22 | #include <config.h> | |
23 | ||
24 | #include "bashtypes.h" | |
25 | #include "posixstat.h" | |
26 | ||
27 | #if defined (HAVE_UNISTD_H) | |
28 | # include <unistd.h> | |
29 | #endif | |
30 | ||
31 | #include "bashansi.h" | |
32 | ||
33 | #include "shell.h" | |
34 | #include "execute_cmd.h" | |
35 | #include "hashcmd.h" | |
36 | ||
37 | extern int hashing_enabled; | |
38 | ||
39 | static int hashing_initialized = 0; | |
40 | ||
41 | HASH_TABLE *hashed_filenames; | |
42 | ||
43 | void | |
44 | initialize_filename_hashing () | |
45 | { | |
46 | if (hashing_initialized == 0) | |
47 | { | |
48 | hashed_filenames = make_hash_table (FILENAME_HASH_BUCKETS); | |
49 | hashing_initialized = 1; | |
50 | } | |
51 | } | |
52 | ||
53 | static void | |
54 | free_filename_data (data) | |
55 | char *data; | |
56 | { | |
57 | free (((PATH_DATA *)data)->path); | |
58 | free (data); | |
59 | } | |
60 | ||
61 | void | |
62 | flush_hashed_filenames () | |
63 | { | |
64 | if (hashed_filenames) | |
65 | flush_hash_table (hashed_filenames, free_filename_data); | |
66 | } | |
67 | ||
68 | /* Remove FILENAME from the table of hashed commands. */ | |
69 | void | |
70 | remove_hashed_filename (filename) | |
71 | char *filename; | |
72 | { | |
73 | register BUCKET_CONTENTS *item; | |
74 | ||
75 | if (hashing_enabled == 0 || hashed_filenames == 0) | |
76 | return; | |
77 | ||
78 | item = remove_hash_item (filename, hashed_filenames); | |
79 | if (item) | |
80 | { | |
81 | if (item->data) | |
82 | free_filename_data (item->data); | |
83 | free (item->key); | |
84 | free (item); | |
85 | } | |
86 | } | |
87 | ||
88 | /* Place FILENAME (key) and FULL_PATHNAME (data->path) into the | |
89 | hash table. CHECK_DOT if non-null is for future calls to | |
90 | find_hashed_filename (); it means that this file was found | |
91 | in a directory in $PATH that is not an absolute pathname. | |
92 | FOUND is the initial value for times_found. */ | |
93 | void | |
94 | remember_filename (filename, full_pathname, check_dot, found) | |
95 | char *filename, *full_pathname; | |
96 | int check_dot, found; | |
97 | { | |
98 | register BUCKET_CONTENTS *item; | |
99 | ||
100 | if (hashing_enabled == 0) | |
101 | return; | |
102 | ||
103 | if (hashed_filenames == 0 || hashing_initialized == 0) | |
104 | initialize_filename_hashing (); | |
105 | ||
106 | item = add_hash_item (filename, hashed_filenames); | |
107 | if (item->data) | |
108 | free (pathdata(item)->path); | |
109 | else | |
110 | { | |
111 | item->key = savestring (filename); | |
112 | item->data = xmalloc (sizeof (PATH_DATA)); | |
113 | } | |
114 | pathdata(item)->path = savestring (full_pathname); | |
115 | pathdata(item)->flags = 0; | |
116 | if (check_dot) | |
117 | pathdata(item)->flags |= HASH_CHKDOT; | |
118 | if (*full_pathname != '/') | |
119 | pathdata(item)->flags |= HASH_RELPATH; | |
120 | item->times_found = found; | |
121 | } | |
122 | ||
123 | /* Return the full pathname that FILENAME hashes to. If FILENAME | |
124 | is hashed, but (data->flags & HASH_CHKDOT) is non-zero, check | |
125 | ./FILENAME and return that if it is executable. This always | |
126 | returns a newly-allocated string; the caller is responsible | |
127 | for freeing it. */ | |
128 | char * | |
129 | find_hashed_filename (filename) | |
130 | char *filename; | |
131 | { | |
132 | register BUCKET_CONTENTS *item; | |
133 | char *path, *dotted_filename, *tail; | |
134 | int same; | |
135 | ||
136 | if (hashing_enabled == 0 || hashed_filenames == 0) | |
137 | return ((char *)NULL); | |
138 | ||
139 | item = find_hash_item (filename, hashed_filenames); | |
140 | ||
141 | if (item == NULL) | |
142 | return ((char *)NULL); | |
143 | ||
144 | /* If this filename is hashed, but `.' comes before it in the path, | |
145 | see if ./filename is executable. If the hashed value is not an | |
146 | absolute pathname, see if ./`hashed-value' exists. */ | |
147 | path = pathdata(item)->path; | |
148 | if (pathdata(item)->flags & (HASH_CHKDOT|HASH_RELPATH)) | |
149 | { | |
150 | tail = (pathdata(item)->flags & HASH_RELPATH) ? path : filename; | |
151 | dotted_filename = xmalloc (3 + strlen (tail)); | |
152 | dotted_filename[0] = '.'; dotted_filename[1] = '/'; | |
153 | strcpy (dotted_filename + 2, tail); | |
154 | ||
155 | if (executable_file (dotted_filename)) | |
156 | return (dotted_filename); | |
157 | ||
158 | free (dotted_filename); | |
159 | ||
160 | #if 0 | |
161 | if (pathdata(item)->flags & HASH_RELPATH) | |
162 | return ((char *)NULL); | |
163 | #endif | |
164 | ||
165 | /* Watch out. If this file was hashed to "./filename", and | |
166 | "./filename" is not executable, then return NULL. */ | |
167 | ||
168 | /* Since we already know "./filename" is not executable, what | |
169 | we're really interested in is whether or not the `path' | |
170 | portion of the hashed filename is equivalent to the current | |
171 | directory, but only if it starts with a `.'. (This catches | |
172 | ./. and so on.) same_file () tests general Unix file | |
173 | equivalence -- same device and inode. */ | |
174 | if (*path == '.') | |
175 | { | |
176 | same = 0; | |
177 | tail = (char *)strrchr (path, '/'); | |
178 | ||
179 | if (tail) | |
180 | { | |
181 | *tail = '\0'; | |
182 | same = same_file (".", path, (struct stat *)NULL, (struct stat *)NULL); | |
183 | *tail = '/'; | |
184 | } | |
185 | ||
186 | return same ? (char *)NULL : savestring (path); | |
187 | } | |
188 | } | |
189 | ||
190 | return (savestring (path)); | |
191 | } |