Re: [Qemu-devel] [patch] replace all strdup() with g_strdup()

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Dec 16, 2011 at 10:26:33AM +0100, Paolo Bonzini wrote:
> On 12/16/2011 09:07 AM, Jun Koi wrote:
> >This patch replaces all the strdup() with g_strdup()
> >
> >Signed-off-by: Jun Koi<junkoi2004@gmail.com>
> >
> >$ diffstat strdup.diff
> >  cmd.c               |    4 ++--
> >  envlist.c           |    6 +++---
> >  exec.c              |    2 +-
> >  hw/isa-bus.c        |    2 +-
> >  hw/pc.c             |    2 +-
> >  hw/pci.c            |    2 +-
> >  hw/qdev.c           |    2 +-
> >  hw/scsi-bus.c       |    2 +-
> >  hw/sun4m.c          |    6 +++---
> >  hw/sun4u.c          |    2 +-
> >  hw/usb-msd.c        |    2 +-
> >  hw/virtio-blk.c     |    2 +-
> >  ia64-dis.c          |    2 +-
> >  microblaze-dis.c    |   18 +++++++++---------
> >  path.c              |    2 +-
> >  readline.c          |    2 +-
> >  test-qmp-commands.c |   12 ++++++------
> >  17 files changed, 35 insertions(+), 35 deletions(-)
> 
> You cannot do this unless you also convert all free to g_free.  So
> you also cannot do this when you are passing strings to libraries
> that take ownership of the strings.  A search-and-replace conversion
> is not possible.

Yes & no. In general you are correct that g_malloc/g_strdup needs to
be matched with g_free, but in the context of the QEMU binary at least
we don't strictly need that.

The general issue is that GLib's memory allocators default to the
system malloc/free, but with    g_mem_set_vtable   it is possible
to override those allocators.

So any libraries using GLib should definitely take care to match
g_malloc/g_strdup/g_free, but if you are a self contained program
that never calls g_mem_set_vtable, we don't technically have to
worry about it.

That all said, we probably *do* want to take care todo the matching
for any parts of the QEMU codebase which may end up being built into
ELF libraries for external consumption.

Regards,
Daniel.
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