How to set breakpoints on future shared libraries with a command flag
C++CLinuxUnixGdbC++ Problem Overview
I'm trying to automate a gdb session using the --command flag. I'm trying to set a breakpoint on a function in a shared library (the Unix equivalent of a DLL) . My cmds.gdb looks like this:
set args /home/shlomi/conf/bugs/kde/font-break.txt
b IA__FcFontMatch
r
However, I'm getting the following:
shlomi:~/progs/bugs-external/kde/font-breaking$ gdb --command=cmds.gdb... GNU gdb 6.8-2mdv2009.0 (Mandriva Linux release 2009.0) Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i586-mandriva-linux-gnu"... (no debugging symbols found) Function "IA__FcFontMatch" not defined. Make breakpoint pending on future shared library load? (y or [n]) [answered N; input not from terminal]
So it doesn't set the breakpoint after all. How can I make it default to answer "y" to set breakpoints on pending future shared library load?
I recall that I was able to do something, but cannot recall what.
C++ Solutions
Solution 1 - C++
Replying to myself, I'd like to give the answer that someone gave me on IRC:
(gdb) apropos pending actions -- Specify the actions to be taken at a tracepoint set breakpoint -- Breakpoint specific settings set breakpoint pending -- Set debugger's behavior regarding pending breakpoints show breakpoint -- Breakpoint specific settings show breakpoint pending -- Show debugger's behavior regarding pending breakpoints
And so set breakpoint pending on does the trick; it is used in cmds.gdb like e.g.
set breakpoint pending on
break <source file name>:<line number>
Solution 2 - C++
OT: In terminal it would look like this to debug Caja in one line:
gdb -ex "set breakpoint pending on" -ex "break gdk_x_error" -ex run --args caja --sync
Solution 3 - C++
With no symbols.
objdump -t /lib/libacl.so
SYMBOL TABLE:
no symbols
objdump -T /lib/libacl.so
...
00002bd0 g DF .text 000000d0 ACL_1.0 acl_delete_entry
...
(gdb) break 0x0002bd0
(gdb) x/20i acl_delete_entry
0x2bd0 <acl_delete_entry>: stwu r1,-32(r1)
0x2bd4 <acl_delete_entry+4>: mflr r0
0x2bd8 <acl_delete_entry+8>: stw r29,20(r1)
0x2bdc <acl_delete_entry+12>: stw r30,24(r1)
0x2be0 <acl_delete_entry+16>: mr r29,r4
0x2be4 <acl_delete_entry+20>: li r4,28972