1: /*
2: * Copyright (c) 2010, 2012-2014 Todd C. Miller <Todd.Miller@courtesan.com>
3: *
4: * Permission to use, copy, modify, and distribute this software for any
5: * purpose with or without fee is hereby granted, provided that the above
6: * copyright notice and this permission notice appear in all copies.
7: *
8: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15: */
16:
17: #include <config.h>
18:
19: #include <sys/types.h>
20:
21: #include <stdio.h>
22: #ifdef STDC_HEADERS
23: # include <stdlib.h>
24: # include <stddef.h>
25: #else
26: # ifdef HAVE_STDLIB_H
27: # include <stdlib.h>
28: # endif
29: #endif /* STDC_HEADERS */
30: #ifdef HAVE_STRING_H
31: # include <string.h>
32: #endif /* HAVE_STRING_H */
33: #ifdef HAVE_STRINGS_H
34: # include <strings.h>
35: #endif /* HAVE_STRINGS_H */
36: #if defined(HAVE_SHL_LOAD)
37: # include <dl.h>
38: #elif defined(HAVE_DLOPEN)
39: # include <dlfcn.h>
40: #endif
41: #include <errno.h>
42:
43: #include "sudo_dso.h"
44: #include "missing.h"
45:
46: /*
47: * Pointer for statically compiled symbols.
48: */
49: static struct sudo_preload_table *preload_table;
50:
51: void
52: sudo_dso_preload_table(struct sudo_preload_table *table)
53: {
54: preload_table = table;
55: }
56:
57: #if defined(HAVE_SHL_LOAD)
58:
59: # ifndef DYNAMIC_PATH
60: # define DYNAMIC_PATH 0
61: # endif
62:
63: void *
64: sudo_dso_load(const char *path, int mode)
65: {
66: struct sudo_preload_table *pt;
67: int flags = DYNAMIC_PATH | BIND_VERBOSE;
68:
69: if (mode == 0)
70: mode = SUDO_DSO_LAZY; /* default behavior */
71:
72: /* Check prelinked symbols first. */
73: if (preload_table != NULL) {
74: for (pt = preload_table; pt->handle != NULL; pt++) {
75: if (pt->path != NULL && strcmp(path, pt->path) == 0)
76: return pt->handle;
77: }
78: }
79:
80: /* We don't support SUDO_DSO_GLOBAL or SUDO_DSO_LOCAL yet. */
81: if (ISSET(mode, SUDO_DSO_LAZY))
82: flags |= BIND_DEFERRED;
83: if (ISSET(mode, SUDO_DSO_NOW))
84: flags |= BIND_IMMEDIATE;
85:
86: return (void *)shl_load(path, flags, 0L);
87: }
88:
89: int
90: sudo_dso_unload(void *handle)
91: {
92: struct sudo_preload_table *pt;
93:
94: /* Check prelinked symbols first. */
95: if (preload_table != NULL) {
96: for (pt = preload_table; pt->handle != NULL; pt++) {
97: if (pt->handle == handle)
98: return 0;
99: }
100: }
101:
102: return shl_unload((shl_t)handle);
103: }
104:
105: void *
106: sudo_dso_findsym(void *vhandle, const char *symbol)
107: {
108: struct sudo_preload_table *pt;
109: shl_t handle = vhandle;
110: void *value = NULL;
111:
112: /* Check prelinked symbols first. */
113: if (preload_table != NULL) {
114: for (pt = preload_table; pt->handle != NULL; pt++) {
115: if (pt->handle == handle) {
116: struct sudo_preload_symbol *sym;
117: for (sym = pt->symbols; sym->name != NULL; sym++) {
118: if (strcmp(sym->name, symbol) == 0)
119: return sym->addr;
120: }
121: errno = ENOENT;
122: return NULL;
123: }
124: }
125: }
126:
127: /*
128: * Note that the behavior of of SUDO_DSO_NEXT and SUDO_DSO_SELF
129: * differs from most implementations when called from
130: * a shared library.
131: */
132: if (vhandle == SUDO_DSO_NEXT) {
133: /* Iterate over all shared libs looking for symbol. */
134: shl_t myhandle = PROG_HANDLE;
135: struct shl_descriptor *desc;
136: int idx = 0;
137:
138: /* Find program's real handle. */
139: if (shl_gethandle(PROG_HANDLE, &desc) == 0)
140: myhandle = desc->handle;
141: while (shl_get(idx++, &desc) == 0) {
142: if (desc->handle == myhandle)
143: continue;
144: if (shl_findsym(&desc->handle, symbol, TYPE_UNDEFINED, &value) == 0)
145: break;
146: }
147: } else {
148: if (vhandle == SUDO_DSO_DEFAULT)
149: handle = NULL;
150: else if (vhandle == SUDO_DSO_SELF)
151: handle = PROG_HANDLE;
152: (void)shl_findsym(&handle, symbol, TYPE_UNDEFINED, &value);
153: }
154:
155: return value;
156: }
157:
158: char *
159: sudo_dso_strerror(void)
160: {
161: return strerror(errno);
162: }
163:
164: #elif defined(HAVE_DLOPEN)
165:
166: # ifndef RTLD_GLOBAL
167: # define RTLD_GLOBAL 0
168: # endif
169:
170: void *
171: sudo_dso_load(const char *path, int mode)
172: {
173: struct sudo_preload_table *pt;
174: int flags = 0;
175:
176: /* Check prelinked symbols first. */
177: if (preload_table != NULL) {
178: for (pt = preload_table; pt->handle != NULL; pt++) {
179: if (pt->path != NULL && strcmp(path, pt->path) == 0)
180: return pt->handle;
181: }
182: }
183:
184: /* Map SUDO_DSO_* -> RTLD_* */
185: if (ISSET(mode, SUDO_DSO_LAZY))
186: flags |= RTLD_LAZY;
187: if (ISSET(mode, SUDO_DSO_NOW))
188: flags |= RTLD_NOW;
189: if (ISSET(mode, SUDO_DSO_GLOBAL))
190: flags |= RTLD_GLOBAL;
191: if (ISSET(mode, SUDO_DSO_LOCAL))
192: flags |= RTLD_LOCAL;
193:
194: return dlopen(path, flags);
195: }
196:
197: int
198: sudo_dso_unload(void *handle)
199: {
200: struct sudo_preload_table *pt;
201:
202: /* Check prelinked symbols first. */
203: if (preload_table != NULL) {
204: for (pt = preload_table; pt->handle != NULL; pt++) {
205: if (pt->handle == handle)
206: return 0;
207: }
208: }
209:
210: return dlclose(handle);
211: }
212:
213: void *
214: sudo_dso_findsym(void *handle, const char *symbol)
215: {
216: struct sudo_preload_table *pt;
217:
218: /* Check prelinked symbols first. */
219: if (preload_table != NULL) {
220: for (pt = preload_table; pt->handle != NULL; pt++) {
221: if (pt->handle == handle) {
222: struct sudo_preload_symbol *sym;
223: for (sym = pt->symbols; sym->name != NULL; sym++) {
224: if (strcmp(sym->name, symbol) == 0)
225: return sym->addr;
226: }
227: errno = ENOENT;
228: return NULL;
229: }
230: }
231: }
232:
233: /*
234: * Not all implementations support the special handles.
235: */
236: if (handle == SUDO_DSO_NEXT) {
237: # ifdef RTLD_NEXT
238: handle = RTLD_NEXT;
239: # else
240: errno = ENOENT;
241: return NULL;
242: # endif
243: } else if (handle == SUDO_DSO_DEFAULT) {
244: # ifdef RTLD_DEFAULT
245: handle = RTLD_DEFAULT;
246: # else
247: errno = ENOENT;
248: return NULL;
249: # endif
250: } else if (handle == SUDO_DSO_SELF) {
251: # ifdef RTLD_SELF
252: handle = RTLD_SELF;
253: # else
254: errno = ENOENT;
255: return NULL;
256: # endif
257: }
258:
259: return dlsym(handle, symbol);
260: }
261:
262: char *
263: sudo_dso_strerror(void)
264: {
265: return dlerror();
266: }
267:
268: #else /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */
269:
270: /*
271: * Emulate dlopen() using a static list of symbols compiled into sudo.
272: */
273: void *
274: sudo_dso_load(const char *path, int mode)
275: {
276: struct sudo_preload_table *pt;
277:
278: /* Check prelinked symbols first. */
279: if (preload_table != NULL) {
280: for (pt = preload_table; pt->handle != NULL; pt++) {
281: if (pt->path != NULL && strcmp(path, pt->path) == 0)
282: return pt->handle;
283: }
284: }
285: return NULL;
286: }
287:
288: int
289: sudo_dso_unload(void *handle)
290: {
291: struct sudo_preload_table *pt;
292:
293: if (preload_table != NULL) {
294: for (pt = preload_table; pt->handle != NULL; pt++) {
295: if (pt->handle == handle)
296: return 0;
297: }
298: }
299: return -1;
300: }
301:
302: void *
303: sudo_dso_findsym(void *handle, const char *symbol)
304: {
305: struct sudo_preload_table *pt;
306:
307: if (preload_table != NULL) {
308: for (pt = preload_table; pt->handle != NULL; pt++) {
309: if (pt->handle == handle) {
310: struct sudo_preload_symbol *sym;
311: for (sym = pt->symbols; sym->name != NULL; sym++) {
312: if (strcmp(sym->name, symbol) == 0)
313: return sym->addr;
314: }
315: }
316: }
317: }
318: errno = ENOENT;
319: return NULL;
320: }
321:
322: char *
323: sudo_dso_strerror(void)
324: {
325: return strerror(errno);
326: }
327: #endif /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */
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