Using Valgrind and gdb in Scratchbox
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Some hints for using valgrind tools in Scratchbox+Maemo
These commands work in the 386 scratchbox target.
First, standard way to use valgrind and gdb. af-sb-init.sh supports parameters for using these tools with a piece of software we want to study:
af-sb-init.sh start --valgrind=my_app af-sb-init.sh start --gdb=my_app
Valgrind will store the results in /tmp/valgrind-my_app.log*. Gdb will show its prompt on load of my_app. This way you can debug/valgrind the program you want.
An interesting example would be: "I want to valgrind my status bar applet". And this is easy:
af-sb-init.sh start --valgrind=maemo_af_desktop
You'll get the results in /tmp/valgrind-maemo_af_desktop.log*
If you want to run other valgrind tools, you would better use these environment variables: * VALGRINDCMD: the command you want to run inside valgrind. * VALGRIND: the valgrind command and parameters.
For example, if you want to run massif of maemo_af_desktop, you would run:
export VALGRINDCMD=maemo_af_desktop
export VALGRIND="valgrind <del>tool=massif </del>num-callers=50
<del>trace-children=yes </del>depth=5 <del>format=html </del>log-file=/tmp/massif
<del>alloc-fn=g_malloc </del>alloc-fn=g_malloc0 --alloc-fn=g_realloc
<del>alloc-fn=g_slice_alloc </del>alloc-fn=g_try_malloc
- -alloc-fn=g_slice_alloc0"
af-sb-init.sh start
... do your stuff ...
af-sb-init.sh stop
And you'll get your massif reports in /tmp (logs) and $PWD (html and postscripts).
If you want valgrind and gdb to find debug packages in Scratchbox, you need to do something like this:
#!/bin/sh # symlinks for debug symfiles in sbox mkdir -p /usr/lib/debug/targets cd /usr/lib/debug/targets ln -sf /usr/lib/debug $(sh -c '. /targets/links/scratchbox.config;echo $SBOX_TARGET_NAME')
This is because when Gdb uses "realpath" on libraries in Sbox it gets a path starting with /targets//... You can see the effect of this if you "strace" Valgrind (or Gdb).
When using Valgrind, you need to remember to use:
export G_SLICE="always-malloc"
Otherwise Valgrind will report bogus leaks (see Gnome Bugzilla for more information on Glib Gslice and Valgrind).
Another thing to remember about Gdb is that the Maemo Sbox cross-gdb cannot debug ARM (EABI) core dumps. You need target Gdb for this. However, because Sbox will use the host (cross-gdb) binary if it exists, you need to tell Sbox to ignore that:
#!/bin/sh # use native Gdb in Scratchbox SBOX_REDIRECT_IGNORE=/usr/bin/gdb /usr/bin/gdb $*
You can check which Gdb is used with "gdb -v". If it says "--host=i686-pc-linux-gnu" on ARM target, it's a cross-gdb.