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cbb099e8 TT |
1 | /* Definitions for BFD wrappers used by GDB. |
2 | ||
6ec53d05 | 3 | Copyright (C) 2011, 2012 |
cbb099e8 TT |
4 | Free Software Foundation, Inc. |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program 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 | This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "gdb_bfd.h" | |
23 | #include "gdb_assert.h" | |
a4453b7e | 24 | #include "gdb_string.h" |
6ec53d05 | 25 | #include "hashtab.h" |
a4453b7e TT |
26 | |
27 | /* See gdb_bfd.h. */ | |
28 | ||
29 | void | |
30 | gdb_bfd_stash_filename (struct bfd *abfd) | |
31 | { | |
32 | char *name = bfd_get_filename (abfd); | |
33 | char *data; | |
34 | ||
35 | data = bfd_alloc (abfd, strlen (name) + 1); | |
36 | strcpy (data, name); | |
37 | ||
38 | /* Unwarranted chumminess with BFD. */ | |
39 | abfd->filename = data; | |
40 | } | |
cbb099e8 | 41 | |
6ec53d05 TT |
42 | /* An object of this type is stored in each BFD's user data. */ |
43 | ||
44 | struct gdb_bfd_data | |
45 | { | |
46 | /* The reference count. */ | |
47 | int refc; | |
48 | ||
49 | /* The mtime of the BFD at the point the cache entry was made. */ | |
50 | time_t mtime; | |
51 | }; | |
52 | ||
53 | /* A hash table storing all the BFDs maintained in the cache. */ | |
54 | ||
55 | static htab_t gdb_bfd_cache; | |
56 | ||
57 | /* The type of an object being looked up in gdb_bfd_cache. We use | |
58 | htab's capability of storing one kind of object (BFD in this case) | |
59 | and using a different sort of object for searching. */ | |
60 | ||
61 | struct gdb_bfd_cache_search | |
62 | { | |
63 | /* The filename. */ | |
64 | const char *filename; | |
65 | /* The mtime. */ | |
66 | time_t mtime; | |
67 | }; | |
68 | ||
69 | /* A hash function for BFDs. */ | |
70 | ||
71 | static hashval_t | |
72 | hash_bfd (const void *b) | |
73 | { | |
74 | const bfd *abfd = b; | |
75 | ||
76 | /* It is simplest to just hash the filename. */ | |
77 | return htab_hash_string (bfd_get_filename (abfd)); | |
78 | } | |
79 | ||
80 | /* An equality function for BFDs. Note that this expects the caller | |
81 | to search using struct gdb_bfd_cache_search only, not BFDs. */ | |
82 | ||
83 | static int | |
84 | eq_bfd (const void *a, const void *b) | |
85 | { | |
86 | const bfd *abfd = a; | |
87 | const struct gdb_bfd_cache_search *s = b; | |
88 | struct gdb_bfd_data *gdata = bfd_usrdata (abfd); | |
89 | ||
90 | return (gdata->mtime == s->mtime | |
91 | && strcmp (bfd_get_filename (abfd), s->filename) == 0); | |
92 | } | |
93 | ||
94 | /* See gdb_bfd.h. */ | |
95 | ||
96 | struct bfd * | |
97 | gdb_bfd_open (const char *name, const char *target, int fd) | |
98 | { | |
99 | hashval_t hash; | |
100 | void **slot; | |
101 | bfd *abfd; | |
102 | struct gdb_bfd_cache_search search; | |
103 | struct stat st; | |
104 | ||
105 | if (gdb_bfd_cache == NULL) | |
106 | gdb_bfd_cache = htab_create_alloc (1, hash_bfd, eq_bfd, NULL, | |
107 | xcalloc, xfree); | |
108 | ||
109 | if (fd == -1) | |
110 | { | |
111 | fd = open (name, O_RDONLY | O_BINARY); | |
112 | if (fd == -1) | |
113 | { | |
114 | bfd_set_error (bfd_error_system_call); | |
115 | return NULL; | |
116 | } | |
117 | } | |
118 | ||
119 | search.filename = name; | |
120 | if (fstat (fd, &st) < 0) | |
121 | { | |
122 | /* Weird situation here. */ | |
123 | search.mtime = 0; | |
124 | } | |
125 | else | |
126 | search.mtime = st.st_mtime; | |
127 | ||
128 | /* Note that this must compute the same result as hash_bfd. */ | |
129 | hash = htab_hash_string (name); | |
130 | /* Note that we cannot use htab_find_slot_with_hash here, because | |
131 | opening the BFD may fail; and this would violate hashtab | |
132 | invariants. */ | |
133 | abfd = htab_find_with_hash (gdb_bfd_cache, &search, hash); | |
134 | if (abfd != NULL) | |
135 | { | |
136 | close (fd); | |
137 | return gdb_bfd_ref (abfd); | |
138 | } | |
139 | ||
140 | abfd = bfd_fopen (name, target, FOPEN_RB, fd); | |
141 | if (abfd == NULL) | |
142 | return NULL; | |
143 | ||
144 | slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, INSERT); | |
145 | gdb_assert (!*slot); | |
146 | *slot = abfd; | |
147 | ||
148 | gdb_bfd_stash_filename (abfd); | |
149 | return gdb_bfd_ref (abfd); | |
150 | } | |
151 | ||
cbb099e8 TT |
152 | /* Close ABFD, and warn if that fails. */ |
153 | ||
154 | static int | |
155 | gdb_bfd_close_or_warn (struct bfd *abfd) | |
156 | { | |
157 | int ret; | |
158 | char *name = bfd_get_filename (abfd); | |
159 | ||
160 | ret = bfd_close (abfd); | |
161 | ||
162 | if (!ret) | |
163 | warning (_("cannot close \"%s\": %s"), | |
164 | name, bfd_errmsg (bfd_get_error ())); | |
165 | ||
166 | return ret; | |
167 | } | |
168 | ||
169 | /* Add reference to ABFD. Returns ABFD. */ | |
170 | ||
171 | struct bfd * | |
172 | gdb_bfd_ref (struct bfd *abfd) | |
173 | { | |
6ec53d05 | 174 | struct gdb_bfd_data *gdata; |
cbb099e8 TT |
175 | |
176 | if (abfd == NULL) | |
177 | return NULL; | |
178 | ||
6ec53d05 | 179 | gdata = bfd_usrdata (abfd); |
cbb099e8 | 180 | |
6ec53d05 | 181 | if (gdata != NULL) |
cbb099e8 | 182 | { |
6ec53d05 | 183 | gdata->refc += 1; |
cbb099e8 TT |
184 | return abfd; |
185 | } | |
186 | ||
6ec53d05 TT |
187 | gdata = bfd_zalloc (abfd, sizeof (struct gdb_bfd_data)); |
188 | gdata->refc = 1; | |
189 | gdata->mtime = bfd_get_mtime (abfd); | |
190 | bfd_usrdata (abfd) = gdata; | |
cbb099e8 TT |
191 | |
192 | return abfd; | |
193 | } | |
194 | ||
195 | /* Unreference and possibly close ABFD. */ | |
196 | ||
197 | void | |
198 | gdb_bfd_unref (struct bfd *abfd) | |
199 | { | |
6ec53d05 TT |
200 | struct gdb_bfd_data *gdata; |
201 | struct gdb_bfd_cache_search search; | |
cbb099e8 TT |
202 | |
203 | if (abfd == NULL) | |
204 | return; | |
205 | ||
6ec53d05 TT |
206 | gdata = bfd_usrdata (abfd); |
207 | gdb_assert (gdata->refc >= 1); | |
cbb099e8 | 208 | |
6ec53d05 TT |
209 | gdata->refc -= 1; |
210 | if (gdata->refc > 0) | |
cbb099e8 TT |
211 | return; |
212 | ||
6ec53d05 TT |
213 | search.filename = bfd_get_filename (abfd); |
214 | ||
215 | if (gdb_bfd_cache && search.filename) | |
216 | { | |
217 | hashval_t hash = htab_hash_string (search.filename); | |
218 | void **slot; | |
219 | ||
220 | search.mtime = gdata->mtime; | |
221 | slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, | |
222 | NO_INSERT); | |
223 | ||
224 | if (slot && *slot) | |
225 | htab_clear_slot (gdb_bfd_cache, slot); | |
226 | } | |
227 | ||
cbb099e8 TT |
228 | bfd_usrdata (abfd) = NULL; /* Paranoia. */ |
229 | ||
cbb099e8 TT |
230 | gdb_bfd_close_or_warn (abfd); |
231 | } |