Commit | Line | Data |
---|---|---|
a3640c75 MK |
1 | /* Target-dependent code for the GNU C Library (glibc). |
2 | ||
28e7fd62 | 3 | Copyright (C) 2002-2013 Free Software Foundation, Inc. |
a3640c75 MK |
4 | |
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
a3640c75 MK |
10 | (at your option) any later version. |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
a3640c75 MK |
19 | |
20 | #include "defs.h" | |
21 | #include "frame.h" | |
22 | #include "symtab.h" | |
23 | #include "symfile.h" | |
24 | #include "objfiles.h" | |
25 | ||
26 | #include "glibc-tdep.h" | |
27 | ||
28 | /* Calling functions in shared libraries. */ | |
29 | ||
a3640c75 MK |
30 | /* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c. |
31 | This function: | |
32 | 1) decides whether a PLT has sent us into the linker to resolve | |
33 | a function reference, and | |
34 | 2) if so, tells us where to set a temporary breakpoint that will | |
35 | trigger when the dynamic linker is done. */ | |
36 | ||
37 | CORE_ADDR | |
bb41a796 | 38 | glibc_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc) |
a3640c75 MK |
39 | { |
40 | /* The GNU dynamic linker is part of the GNU C library, and is used | |
41 | by all GNU systems (GNU/Hurd, GNU/Linux). An unresolved PLT | |
42 | entry points to "_dl_runtime_resolve", which calls "fixup" to | |
43 | patch the PLT, and then passes control to the function. | |
44 | ||
45 | We look for the symbol `_dl_runtime_resolve', and find `fixup' in | |
46 | the same objfile. If we are at the entry point of `fixup', then | |
47 | we set a breakpoint at the return address (at the top of the | |
48 | stack), and continue. | |
49 | ||
50 | It's kind of gross to do all these checks every time we're | |
51 | called, since they don't change once the executable has gotten | |
52 | started. But this is only a temporary hack --- upcoming versions | |
53 | of GNU/Linux will provide a portable, efficient interface for | |
54 | debugging programs that use shared libraries. */ | |
55 | ||
56 | struct objfile *objfile; | |
57 | struct minimal_symbol *resolver | |
0d5392b8 | 58 | = lookup_minimal_symbol_and_objfile ("_dl_runtime_resolve", &objfile); |
a3640c75 MK |
59 | |
60 | if (resolver) | |
61 | { | |
bdfb3870 | 62 | /* The dynamic linker began using this name in early 2005. */ |
a3640c75 | 63 | struct minimal_symbol *fixup |
bdfb3870 JB |
64 | = lookup_minimal_symbol ("_dl_fixup", NULL, objfile); |
65 | ||
66 | /* This is the name used in older versions. */ | |
67 | if (! fixup) | |
68 | fixup = lookup_minimal_symbol ("fixup", NULL, objfile); | |
a3640c75 MK |
69 | |
70 | if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc) | |
c7ce8faa | 71 | return frame_unwind_caller_pc (get_current_frame ()); |
a3640c75 MK |
72 | } |
73 | ||
74 | return 0; | |
75 | } |