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1 | /* hashcmd.c - functions for managing a hash table mapping command names to | |
2 | full pathnames. */ | |
3 | ||
4 | /* Copyright (C) 1997-2009 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 | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation, either version 3 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | Bash is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with Bash. If not, see <http://www.gnu.org/licenses/>. | |
20 | */ | |
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 "findcmd.h" | |
35 | #include "hashcmd.h" | |
36 | ||
37 | extern int hashing_enabled; | |
38 | ||
39 | HASH_TABLE *hashed_filenames = (HASH_TABLE *)NULL; | |
40 | ||
41 | static void phash_freedata __P((PTR_T)); | |
42 | ||
43 | void | |
44 | phash_create () | |
45 | { | |
46 | if (hashed_filenames == 0) | |
47 | hashed_filenames = hash_create (FILENAME_HASH_BUCKETS); | |
48 | } | |
49 | ||
50 | static void | |
51 | phash_freedata (data) | |
52 | PTR_T data; | |
53 | { | |
54 | free (((PATH_DATA *)data)->path); | |
55 | free (data); | |
56 | } | |
57 | ||
58 | void | |
59 | phash_flush () | |
60 | { | |
61 | if (hashed_filenames) | |
62 | hash_flush (hashed_filenames, phash_freedata); | |
63 | } | |
64 | ||
65 | /* Remove FILENAME from the table of hashed commands. */ | |
66 | int | |
67 | phash_remove (filename) | |
68 | const char *filename; | |
69 | { | |
70 | register BUCKET_CONTENTS *item; | |
71 | ||
72 | if (hashing_enabled == 0 || hashed_filenames == 0) | |
73 | return 0; | |
74 | ||
75 | item = hash_remove (filename, hashed_filenames, 0); | |
76 | if (item) | |
77 | { | |
78 | if (item->data) | |
79 | phash_freedata (item->data); | |
80 | free (item->key); | |
81 | free (item); | |
82 | return 0; | |
83 | } | |
84 | return 1; | |
85 | } | |
86 | ||
87 | /* Place FILENAME (key) and FULL_PATH (data->path) into the | |
88 | hash table. CHECK_DOT if non-null is for future calls to | |
89 | phash_search (); it means that this file was found | |
90 | in a directory in $PATH that is not an absolute pathname. | |
91 | FOUND is the initial value for times_found. */ | |
92 | void | |
93 | phash_insert (filename, full_path, check_dot, found) | |
94 | char *filename, *full_path; | |
95 | int check_dot, found; | |
96 | { | |
97 | register BUCKET_CONTENTS *item; | |
98 | ||
99 | if (hashing_enabled == 0) | |
100 | return; | |
101 | ||
102 | if (hashed_filenames == 0) | |
103 | phash_create (); | |
104 | ||
105 | item = hash_insert (filename, hashed_filenames, 0); | |
106 | if (item->data) | |
107 | free (pathdata(item)->path); | |
108 | else | |
109 | { | |
110 | item->key = savestring (filename); | |
111 | item->data = xmalloc (sizeof (PATH_DATA)); | |
112 | } | |
113 | pathdata(item)->path = savestring (full_path); | |
114 | pathdata(item)->flags = 0; | |
115 | if (check_dot) | |
116 | pathdata(item)->flags |= HASH_CHKDOT; | |
117 | if (*full_path != '/') | |
118 | pathdata(item)->flags |= HASH_RELPATH; | |
119 | item->times_found = found; | |
120 | } | |
121 | ||
122 | /* Return the full pathname that FILENAME hashes to. If FILENAME | |
123 | is hashed, but (data->flags & HASH_CHKDOT) is non-zero, check | |
124 | ./FILENAME and return that if it is executable. This always | |
125 | returns a newly-allocated string; the caller is responsible | |
126 | for freeing it. */ | |
127 | char * | |
128 | phash_search (filename) | |
129 | const char *filename; | |
130 | { | |
131 | register BUCKET_CONTENTS *item; | |
132 | char *path, *dotted_filename, *tail; | |
133 | int same; | |
134 | ||
135 | if (hashing_enabled == 0 || hashed_filenames == 0) | |
136 | return ((char *)NULL); | |
137 | ||
138 | item = hash_search (filename, hashed_filenames, 0); | |
139 | ||
140 | if (item == NULL) | |
141 | return ((char *)NULL); | |
142 | ||
143 | /* If this filename is hashed, but `.' comes before it in the path, | |
144 | see if ./filename is executable. If the hashed value is not an | |
145 | absolute pathname, see if ./`hashed-value' exists. */ | |
146 | path = pathdata(item)->path; | |
147 | if (pathdata(item)->flags & (HASH_CHKDOT|HASH_RELPATH)) | |
148 | { | |
149 | tail = (pathdata(item)->flags & HASH_RELPATH) ? path : (char *)filename; /* XXX - fix const later */ | |
150 | /* If the pathname does not start with a `./', add a `./' to it. */ | |
151 | if (tail[0] != '.' || tail[1] != '/') | |
152 | { | |
153 | dotted_filename = (char *)xmalloc (3 + strlen (tail)); | |
154 | dotted_filename[0] = '.'; dotted_filename[1] = '/'; | |
155 | strcpy (dotted_filename + 2, tail); | |
156 | } | |
157 | else | |
158 | dotted_filename = savestring (tail); | |
159 | ||
160 | if (executable_file (dotted_filename)) | |
161 | return (dotted_filename); | |
162 | ||
163 | free (dotted_filename); | |
164 | ||
165 | #if 0 | |
166 | if (pathdata(item)->flags & HASH_RELPATH) | |
167 | return ((char *)NULL); | |
168 | #endif | |
169 | ||
170 | /* Watch out. If this file was hashed to "./filename", and | |
171 | "./filename" is not executable, then return NULL. */ | |
172 | ||
173 | /* Since we already know "./filename" is not executable, what | |
174 | we're really interested in is whether or not the `path' | |
175 | portion of the hashed filename is equivalent to the current | |
176 | directory, but only if it starts with a `.'. (This catches | |
177 | ./. and so on.) same_file () tests general Unix file | |
178 | equivalence -- same device and inode. */ | |
179 | if (*path == '.') | |
180 | { | |
181 | same = 0; | |
182 | tail = (char *)strrchr (path, '/'); | |
183 | ||
184 | if (tail) | |
185 | { | |
186 | *tail = '\0'; | |
187 | same = same_file (".", path, (struct stat *)NULL, (struct stat *)NULL); | |
188 | *tail = '/'; | |
189 | } | |
190 | ||
191 | return same ? (char *)NULL : savestring (path); | |
192 | } | |
193 | } | |
194 | ||
195 | return (savestring (path)); | |
196 | } |