Re: [Qemu-devel] [PATCH v3 2/5] add qemu_fopen_err

[Alon Levy <alevy@redhat.com>]

On Fri, Mar 23, 2012 at 11:22:48AM -0300, Luiz Capitulino wrote:
> On Sun, 18 Mar 2012 19:29:10 +0100
> Alon Levy <alevy@redhat.com> wrote:
> 
> > This adds a helper to conveniently set the correct error based on the
> > errno after a failed fopen.
> > 
> > The added function is placed in it's own c file to allow libcacard to
> > not develop dependencies on everything that qerror will bring in, which
> > includes monitor and half of qemu. I tried to make it as less ugly as I
> > could, by naming an osdep-no-qerror-obj-y and having that included in
> > osdep-obj-y, and using only the former for libcacard.
> 
> I'm not sure I like this, how will libcacard report errors then?

libcacard is a standalone library, it reports errors via it's existing
interfaces. Changing it to use qerror is possibly a good idea but not
part of this patchset.

> 
> > 
> > Signed-off-by: Alon Levy <alevy@redhat.com>
> > ---
> >  Makefile.objs      |    8 +++++---
> >  libcacard/Makefile |    2 +-
> >  osdep-qerror.c     |   52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  osdep-qerror.h     |    8 ++++++++
> >  osdep.c            |    1 -
> >  5 files changed, 66 insertions(+), 5 deletions(-)
> >  create mode 100644 osdep-qerror.c
> >  create mode 100644 osdep-qerror.h
> > 
> > diff --git a/Makefile.objs b/Makefile.objs
> > index 226b01d..fb5a73a 100644
> > --- a/Makefile.objs
> > +++ b/Makefile.objs
> > @@ -20,9 +20,11 @@ universal-obj-y += $(qom-obj-y)
> >  
> >  #######################################################################
> >  # oslib-obj-y is code depending on the OS (win32 vs posix)
> > -oslib-obj-y = osdep.o
> > -oslib-obj-$(CONFIG_WIN32) += oslib-win32.o qemu-thread-win32.o
> > -oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
> > +oslib-no-qerror-obj-y = osdep.o
> > +oslib-no-qerror-obj-$(CONFIG_WIN32) += oslib-win32.o qemu-thread-win32.o
> > +oslib-no-qerror-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
> > +oslib-obj-y = $(oslib-no-qerror-obj-y)
> > +oslib-obj-y += osdep-qerror.o
> >  
> >  #######################################################################
> >  # coroutines
> > diff --git a/libcacard/Makefile b/libcacard/Makefile
> > index c6a896a..83f483f 100644
> > --- a/libcacard/Makefile
> > +++ b/libcacard/Makefile
> > @@ -8,7 +8,7 @@ libcacard_includedir=$(includedir)/cacard
> >  $(call set-vpath, $(SRC_PATH):$(libcacard_srcpath))
> >  
> >  # objects linked against normal qemu binaries, not compiled with libtool
> > -QEMU_OBJS=$(addprefix ../,$(oslib-obj-y) qemu-timer-common.o $(trace-obj-y))
> > +QEMU_OBJS=$(addprefix ../,$(oslib-no-qerror-obj-y) qemu-timer-common.o $(trace-obj-y))
> >  
> >  # objects linked into a shared library, built with libtool with -fPIC if required
> >  QEMU_OBJS_LIB=$(addsuffix .lo,$(basename $(QEMU_OBJS)))
> > diff --git a/osdep-qerror.c b/osdep-qerror.c
> > new file mode 100644
> > index 0000000..6dac984
> > --- /dev/null
> > +++ b/osdep-qerror.c
> > @@ -0,0 +1,52 @@
> > +#include "qerror.h"
> > +
> > +#include "osdep-qerror.h"
> > +
> > +/*
> > + * Helper to set an Error after a failed fopen.
> > + *
> > + * Uses errno so it must not be changed by another intermediate call.
> > + */
> > +void qemu_fopen_err(Error **errp, const char *file_name)
> > +{
> > +    const char *fmt = NULL;
> 
> Where's the fopen() call and the mode argument?
> 
> > +
> > +    switch (errno) {
> > +    case EACCES:
> > +        fmt = QERR_EACCES;
> > +        break;
> > +    case EINTR:
> > +        fmt = QERR_EINTR;
> > +        break;
> > +    case EEXIST:
> > +        fmt = QERR_EEXIST;
> > +        break;
> > +    case EMFILE:
> > +        fmt = QERR_OPEN_FILE_EMFILE;
> > +        break;
> > +    case ENOSPC:
> > +        fmt = QERR_ENOSPC;
> > +        break;
> > +    case EPERM:
> > +        fmt = QERR_EPERM;
> > +        break;
> > +    case EROFS:
> > +        fmt = QERR_READ_ONLY;
> > +        break;
> > +    case ENOTDIR:
> > +        fmt = QERR_ENOTDIR;
> > +        break;
> > +    case EFBIG:
> > +        fmt = QERR_EFBIG;
> > +        break;
> > +    default:
> > +        /*
> > +         * EINVAL and ENOTSUP will result in the default
> > +         *
> > +         * ENOENT too, it's used by (for instance) bdrv_create_file for
> > +         * a different purpose then open (2) so just give a generic error.
> > +         */
> > +        fmt = QERR_OPEN_FILE_FAILED;
> > +    }
> > +    error_set(errp, fmt, file_name);
> > +}
> > diff --git a/osdep-qerror.h b/osdep-qerror.h
> > new file mode 100644
> > index 0000000..7320f4a
> > --- /dev/null
> > +++ b/osdep-qerror.h
> > @@ -0,0 +1,8 @@
> > +#ifndef OSDEP_QERROR_H
> > +#define OSDEP_QERROR_H
> > +
> > +#include "error.h"
> > +
> > +void qemu_fopen_err(Error **errp, const char *file_name);
> > +
> > +#endif
> > diff --git a/osdep.c b/osdep.c
> > index 3e6bada..efdd21c 100644
> > --- a/osdep.c
> > +++ b/osdep.c
> > @@ -241,4 +241,3 @@ ssize_t qemu_recv_full(int fd, void *buf, size_t count, int flags)
> >  
> >      return total;
> >  }
> > -
> 
>