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2449ae7b | 1 | /* ld.so error exception allocation and deallocation. |
581c785b | 2 | Copyright (C) 1995-2022 Free Software Foundation, Inc. |
2449ae7b FW |
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 | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
2449ae7b FW |
18 | |
19 | #include <ldsodefs.h> | |
20 | #include <limits.h> | |
21 | #include <stdarg.h> | |
22 | #include <stdbool.h> | |
23 | #include <stdint.h> | |
24 | #include <string.h> | |
25 | #include <unistd.h> | |
ce7387cc | 26 | #include <_itoa.h> |
2449ae7b FW |
27 | |
28 | /* This message we return as a last resort. We define the string in a | |
29 | variable since we have to avoid freeing it and so have to enable | |
30 | a pointer comparison. See below and in dlfcn/dlerror.c. */ | |
31 | static const char _dl_out_of_memory[] = "out of memory"; | |
32 | ||
fada9018 FW |
33 | /* Call free in the main libc.so. This allows other namespaces to |
34 | free pointers on the main libc heap, via GLRO (dl_error_free). It | |
35 | also avoids calling free on the special, pre-allocated | |
36 | out-of-memory error message. */ | |
37 | void | |
38 | _dl_error_free (void *ptr) | |
39 | { | |
40 | if (ptr != _dl_out_of_memory) | |
41 | free (ptr); | |
42 | } | |
43 | ||
2449ae7b FW |
44 | /* Dummy allocation object used if allocating the message buffer |
45 | fails. */ | |
46 | static void | |
47 | oom_exception (struct dl_exception *exception) | |
48 | { | |
49 | exception->objname = ""; | |
50 | exception->errstring = _dl_out_of_memory; | |
51 | exception->message_buffer = NULL; | |
52 | } | |
53 | ||
54 | static void | |
55 | __attribute__ ((noreturn)) | |
56 | length_mismatch (void) | |
57 | { | |
58 | _dl_fatal_printf ("Fatal error: " | |
59 | "length accounting in _dl_exception_create_format\n"); | |
60 | } | |
61 | ||
62 | /* Adjust the message buffer to indicate whether it is possible to | |
63 | free it. EXCEPTION->errstring must be a potentially deallocatable | |
64 | pointer. */ | |
65 | static void | |
66 | adjust_message_buffer (struct dl_exception *exception) | |
67 | { | |
68 | /* If the main executable is relocated it means the libc's malloc | |
69 | is used. */ | |
70 | bool malloced = true; | |
71 | #ifdef SHARED | |
72 | malloced = (GL(dl_ns)[LM_ID_BASE]._ns_loaded != NULL | |
73 | && (GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_relocated != 0)); | |
74 | #endif | |
75 | if (malloced) | |
76 | exception->message_buffer = (char *) exception->errstring; | |
77 | else | |
78 | exception->message_buffer = NULL; | |
79 | } | |
80 | ||
81 | void | |
82 | _dl_exception_create (struct dl_exception *exception, const char *objname, | |
83 | const char *errstring) | |
84 | { | |
85 | if (objname == NULL) | |
86 | objname = ""; | |
87 | size_t len_objname = strlen (objname) + 1; | |
88 | size_t len_errstring = strlen (errstring) + 1; | |
89 | char *errstring_copy = malloc (len_objname + len_errstring); | |
90 | if (errstring_copy != NULL) | |
91 | { | |
92 | /* Make a copy of the object file name and the error string. */ | |
93 | exception->objname = memcpy (__mempcpy (errstring_copy, | |
94 | errstring, len_errstring), | |
95 | objname, len_objname); | |
96 | exception->errstring = errstring_copy; | |
97 | adjust_message_buffer (exception); | |
98 | } | |
99 | else | |
100 | oom_exception (exception); | |
101 | } | |
102 | rtld_hidden_def (_dl_exception_create) | |
103 | ||
104 | void | |
105 | _dl_exception_create_format (struct dl_exception *exception, const char *objname, | |
106 | const char *fmt, ...) | |
107 | { | |
108 | if (objname == NULL) | |
109 | objname = ""; | |
110 | size_t len_objname = strlen (objname) + 1; | |
111 | /* Compute the length of the result. Include room for two NUL | |
112 | bytes. */ | |
113 | size_t length = len_objname + 1; | |
114 | { | |
115 | va_list ap; | |
116 | va_start (ap, fmt); | |
117 | for (const char *p = fmt; *p != '\0'; ++p) | |
118 | if (*p == '%') | |
119 | { | |
120 | ++p; | |
121 | switch (*p) | |
122 | { | |
123 | case 's': | |
124 | length += strlen (va_arg (ap, const char *)); | |
125 | break; | |
a5275ba5 L |
126 | /* Recognize the l modifier. It is only important on some |
127 | platforms where long and int have a different size. We | |
128 | can use the same code for size_t. */ | |
129 | case 'l': | |
130 | case 'z': | |
131 | if (p[1] == 'x') | |
132 | { | |
133 | length += LONG_WIDTH / 4; | |
134 | ++p; | |
135 | break; | |
136 | } | |
32db86d5 | 137 | /* Fall through. */ |
a5275ba5 L |
138 | case 'x': |
139 | length += INT_WIDTH / 4; | |
140 | break; | |
2449ae7b FW |
141 | default: |
142 | /* Assumed to be '%'. */ | |
143 | ++length; | |
144 | break; | |
145 | } | |
146 | } | |
147 | else | |
148 | ++length; | |
149 | va_end (ap); | |
150 | } | |
151 | ||
152 | if (length > PTRDIFF_MAX) | |
153 | { | |
154 | oom_exception (exception); | |
155 | return; | |
156 | } | |
157 | char *errstring = malloc (length); | |
158 | if (errstring == NULL) | |
159 | { | |
160 | oom_exception (exception); | |
161 | return; | |
162 | } | |
163 | exception->errstring = errstring; | |
164 | adjust_message_buffer (exception); | |
165 | ||
166 | /* Copy the error message to errstring. */ | |
167 | { | |
168 | /* Next byte to be written in errstring. */ | |
169 | char *wptr = errstring; | |
170 | /* End of the allocated string. */ | |
171 | char *const end = errstring + length; | |
172 | ||
173 | va_list ap; | |
174 | va_start (ap, fmt); | |
175 | ||
176 | for (const char *p = fmt; *p != '\0'; ++p) | |
177 | if (*p == '%') | |
178 | { | |
179 | ++p; | |
180 | switch (*p) | |
181 | { | |
182 | case 's': | |
183 | { | |
184 | const char *ptr = va_arg (ap, const char *); | |
185 | size_t len_ptr = strlen (ptr); | |
186 | if (len_ptr > end - wptr) | |
187 | length_mismatch (); | |
188 | wptr = __mempcpy (wptr, ptr, len_ptr); | |
189 | } | |
190 | break; | |
191 | case '%': | |
192 | if (wptr == end) | |
193 | length_mismatch (); | |
194 | *wptr = '%'; | |
195 | ++wptr; | |
196 | break; | |
a5275ba5 L |
197 | case 'x': |
198 | { | |
199 | unsigned long int num = va_arg (ap, unsigned int); | |
200 | char *start = wptr; | |
201 | wptr += INT_WIDTH / 4; | |
202 | char *cp = _itoa (num, wptr, 16, 0); | |
203 | /* Pad to the full width with 0. */ | |
204 | while (cp != start) | |
205 | *--cp = '0'; | |
206 | } | |
207 | break; | |
208 | case 'l': | |
209 | case 'z': | |
210 | if (p[1] == 'x') | |
211 | { | |
212 | unsigned long int num = va_arg (ap, unsigned long int); | |
213 | char *start = wptr; | |
214 | wptr += LONG_WIDTH / 4; | |
215 | char *cp = _itoa (num, wptr, 16, 0); | |
216 | /* Pad to the full width with 0. */ | |
217 | while (cp != start) | |
218 | *--cp = '0'; | |
219 | ++p; | |
220 | break; | |
221 | } | |
222 | /* FALLTHROUGH */ | |
2449ae7b FW |
223 | default: |
224 | _dl_fatal_printf ("Fatal error:" | |
225 | " invalid format in exception string\n"); | |
226 | } | |
227 | } | |
228 | else | |
229 | { | |
230 | if (wptr == end) | |
231 | length_mismatch (); | |
232 | *wptr = *p; | |
233 | ++wptr; | |
234 | } | |
235 | ||
236 | if (wptr == end) | |
237 | length_mismatch (); | |
238 | *wptr = '\0'; | |
239 | ++wptr; | |
240 | if (len_objname != end - wptr) | |
241 | length_mismatch (); | |
242 | exception->objname = memcpy (wptr, objname, len_objname); | |
81046e28 | 243 | va_end (ap); |
2449ae7b FW |
244 | } |
245 | } | |
246 | rtld_hidden_def (_dl_exception_create_format) | |
247 | ||
248 | void | |
249 | _dl_exception_free (struct dl_exception *exception) | |
250 | { | |
251 | free (exception->message_buffer); | |
252 | exception->objname = NULL; | |
253 | exception->errstring = NULL; | |
254 | exception->message_buffer = NULL; | |
255 | } | |
256 | rtld_hidden_def (_dl_exception_free) |