1 /*
2 * libjingle
3 * Copyright 2004 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "talk/media/devices/libudevsymboltable.h"
29
30 #include <dlfcn.h>
31
32 #include "webrtc/base/logging.h"
33
34 namespace cricket {
35
36 #define LATE_BINDING_SYMBOL_TABLE_CLASS_NAME LIBUDEV_SYMBOLS_CLASS_NAME
37 #define LATE_BINDING_SYMBOL_TABLE_SYMBOLS_LIST LIBUDEV_SYMBOLS_LIST
38 #define LATE_BINDING_SYMBOL_TABLE_DLL_NAME "libudev.so.0"
39 #include "webrtc/base/latebindingsymboltable.cc.def"
40 #undef LATE_BINDING_SYMBOL_TABLE_CLASS_NAME
41 #undef LATE_BINDING_SYMBOL_TABLE_SYMBOLS_LIST
42 #undef LATE_BINDING_SYMBOL_TABLE_DLL_NAME
43
IsWrongLibUDevAbiVersion(rtc::DllHandle libudev_0)44 bool IsWrongLibUDevAbiVersion(rtc::DllHandle libudev_0) {
45 rtc::DllHandle libudev_1 = dlopen("libudev.so.1",
46 RTLD_NOW|RTLD_LOCAL|RTLD_NOLOAD);
47 bool unsafe_symlink = (libudev_0 == libudev_1);
48 if (unsafe_symlink) {
49 // .0 and .1 are distinct ABIs, so if they point to the same thing then one
50 // of them must be wrong. Probably the old has been symlinked to the new in
51 // a misguided attempt at backwards compatibility.
52 LOG(LS_ERROR) << "libudev.so.0 and libudev.so.1 unsafely point to the"
53 " same thing; not using libudev";
54 } else if (libudev_1) {
55 // If libudev.so.1 is resident but distinct from libudev.so.0, then some
56 // system library loaded the new ABI separately. This is not a problem for
57 // LateBindingSymbolTable because its symbol look-ups are restricted to its
58 // DllHandle, but having libudev.so.0 resident may cause problems for that
59 // system library because symbol names are not namespaced by DLL. (Although
60 // our use of RTLD_LOCAL should avoid most problems.)
61 LOG(LS_WARNING)
62 << "libudev.so.1 is resident but distinct from libudev.so.0";
63 }
64 if (libudev_1) {
65 // Release the refcount that we acquired above. (Does not unload the DLL;
66 // whoever loaded it still needs it.)
67 dlclose(libudev_1);
68 }
69 return unsafe_symlink;
70 }
71
72 } // namespace cricket
73