1/* Memory management for dlerror messages.
2 Copyright (C) 2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _DLERROR_H
20#define _DLERROR_H
21
22#include <dlfcn.h>
23#include <ldsodefs.h>
24#include <stdbool.h>
25#include <stdint.h>
26#include <stdlib.h>
27
28/* Source of the errstring member in struct dl_action_result, for
29 finding the right deallocation routine. */
30enum dl_action_result_errstring_source
31 {
32 dl_action_result_errstring_constant, /* String literal, no deallocation. */
33 dl_action_result_errstring_rtld, /* libc in the primary namespace. */
34 dl_action_result_errstring_local, /* libc in the current namespace. */
35 };
36
37struct dl_action_result
38{
39 int errcode;
40 char errstring_source;
41 bool returned;
42 const char *objname;
43 char *errstring;
44};
45
46/* Used to free the errstring member of struct dl_action_result in the
47 dl_action_result_errstring_rtld case. */
48static inline void
49dl_error_free (void *ptr)
50{
51#ifdef SHARED
52 /* In the shared case, ld.so may use a different malloc than this
53 namespace. */
54 GLRO (dl_error_free (ptr));
55#else
56 /* Call the implementation directly. It still has to check for
57 pointers which cannot be freed, so do not call free directly
58 here. */
59 _dl_error_free (ptr);
60#endif
61}
62
63/* Deallocate RESULT->errstring, leaving *RESULT itself allocated. */
64static inline void
65dl_action_result_errstring_free (struct dl_action_result *result)
66{
67 switch (result->errstring_source)
68 {
69 case dl_action_result_errstring_constant:
70 break;
71 case dl_action_result_errstring_rtld:
72 dl_error_free (result->errstring);
73 break;
74 case dl_action_result_errstring_local:
75 free (result->errstring);
76 break;
77 }
78}
79
80/* Stand-in for an error result object whose allocation failed. No
81 precise message can be reported for this, but an error must still
82 be signaled. */
83static struct dl_action_result *const dl_action_result_malloc_failed
84 __attribute__ ((unused)) = (struct dl_action_result *) (intptr_t) -1;
85
86/* Thread-local variable for storing dlfcn failures for subsequent
87 reporting via dlerror. */
88extern __thread struct dl_action_result *__libc_dlerror_result
89 attribute_tls_model_ie;
90void __libc_dlerror_result_free (void) attribute_hidden;
91
92#endif /* _DLERROR_H */
93