Re: [Qemu-devel] [PATCH] Add optional dump of default config file paths..

[Anthony Liguori]

On 06/14/2010 12:59 PM, john cooper wrote:
> Anthony Liguori wrote:
>    
> > On 06/09/2010 03:05 AM, john cooper wrote:
> >      
> > > This patch adds the ability to determine the build-configured
> > > runtime "config file" paths from the command line.  After
> > > support for cpu model definitions were added to the default
> > > runtime "target-" config file, testing of this feature has
> > > tripped over an unintentionally mis-installed config file
> > > enough to indicate some help is needed resolving such issues.
> > >
> > > As no general "verbose" flag is currently available, specifying
> > > "-readconfig ?" on the command line will maintain the default
> > > (config file) disposition but additionally emit diagnostic info.
> > > This mode is optional, otherwise the existing startup behavior
> > > is identical.
> > >
> > >        
> > I assume this is something requested by libvirt?
> >      
> Not requested by libvirt but rather intended for the qemu
> CLI facing user.  The alternatives of trying to puzzle
> out built-in config file paths via strace or strings when
> config problems surface is rather awkward.  This also
> seems a general need for test of config file related
> functionality.
>    

I wouldn't mind spitting out the ./configure line in qemu -version like 
gcc does.  That has the benefit of being a bit more obviously discoverable.

Regards,

Anthony Liguori

> Thanks,
>
> -john
>
>    
> > I'd prefer we support
> > this via Daniel's capabilities patchset instead of adding yet another
> > hidden help output and having libvirt parse that output.
> >
> > Regards,
> >
> > Anthony Liguori
> >
> >      
> > > Signed-off-by: john cooper<address@hidden>
> > > ---
> > >
> > > diff --git a/qemu-config.c b/qemu-config.c
> > > index 5a4e61b..a490603 100644
> > > --- a/qemu-config.c
> > > +++ b/qemu-config.c
> > > @@ -518,21 +518,29 @@ out:
> > >        return res;
> > >    }
> > >
> > > -int qemu_read_config_file(const char *filename)
> > > +/* attempt to open and parse config file, report problems if vflag
> > > + */
> > > +int qemu_read_config_file(const char *filename, int vflag)
> > >    {
> > >        FILE *f = fopen(filename, "r");
> > > -    int ret;
> > > +    int rv = 0;
> > >
> > >        if (f == NULL) {
> > > -        return -errno;
> > > +        rv = -errno;
> > >        }
> > > -
> > > -    ret = qemu_config_parse(f, vm_config_groups, filename);
> > > -    fclose(f);
> > > -
> > > -    if (ret == 0) {
> > > -        return 0;
> > > -    } else {
> > > -        return -EINVAL;
> > > +    else if (qemu_config_parse(f, vm_config_groups, filename) != 0) {
> > > +        rv = -EINVAL;
> > > +    }
> > > +    else if (vflag) {
> > > +        fprintf(stderr, "read config file %s\n", filename);
> > >        }
> > > +    if (f) {
> > > +        fclose(f);
> > > +    }
> > > +    if (rv&&   vflag) {
> > > +        fprintf(stderr, "can't read config file %s: %s\n",
> > > +                filename, strerror(-rv));
> > > +    }
> > > +    return rv;
> > >    }
> > > +
> > > diff --git a/qemu-config.h b/qemu-config.h
> > > index dca69d4..2e15556 100644
> > > --- a/qemu-config.h
> > > +++ b/qemu-config.h
> > > @@ -23,6 +23,6 @@ void qemu_add_globals(void);
> > >    void qemu_config_write(FILE *fp);
> > >    int qemu_config_parse(FILE *fp, QemuOptsList **lists, const char
> > > *fname);
> > >
> > > -int qemu_read_config_file(const char *filename);
> > > +int qemu_read_config_file(const char *filename, int vflag);
> > >
> > >    #endif /* QEMU_CONFIG_H */
> > > diff --git a/vl.c b/vl.c
> > > index 7121cd0..23c7276 100644
> > > --- a/vl.c
> > > +++ b/vl.c
> > > @@ -2582,6 +2582,7 @@ int main(int argc, char **argv, char **envp)
> > >    #endif
> > >        int show_vnc_port = 0;
> > >        int defconfig = 1;
> > > +    int defconfig_verbose = 0;
> > >
> > >        error_set_progname(argv[0]);
> > >
> > > @@ -2657,6 +2658,10 @@ int main(int argc, char **argv, char **envp)
> > >                case QEMU_OPTION_nodefconfig:
> > >                    defconfig=0;
> > >                    break;
> > > +            case QEMU_OPTION_readconfig:
> > > +                if (!strcmp(optarg, "?"))
> > > +                    defconfig_verbose = 1;
> > > +                break;
> > >                }
> > >            }
> > >        }
> > > @@ -2664,12 +2669,14 @@ int main(int argc, char **argv, char **envp)
> > >        if (defconfig) {
> > >            int ret;
> > >
> > > -        ret = qemu_read_config_file(CONFIG_QEMU_CONFDIR "/qemu.conf");
> > > +        ret = qemu_read_config_file(CONFIG_QEMU_CONFDIR "/qemu.conf",
> > > +                                    defconfig_verbose);
> > >            if (ret<   0&&   ret != -ENOENT) {
> > >                exit(1);
> > >            }
> > >
> > > -        ret = qemu_read_config_file(arch_config_name);
> > > +        ret = qemu_read_config_file(arch_config_name,
> > > +                                    defconfig_verbose);
> > >            if (ret<   0&&   ret != -ENOENT) {
> > >                exit(1);
> > >            }
> > > @@ -3386,15 +3393,9 @@ int main(int argc, char **argv, char **envp)
> > >                    xen_mode = XEN_ATTACH;
> > >                    break;
> > >                case QEMU_OPTION_readconfig:
> > > -                {
> > > -                    int ret = qemu_read_config_file(optarg);
> > > -                    if (ret<   0) {
> > > -                        fprintf(stderr, "read config %s: %s\n", optarg,
> > > -                            strerror(-ret));
> > > -                        exit(1);
> > > -                    }
> > > -                    break;
> > > -                }
> > > +                if (!defconfig_verbose&&
> > > qemu_read_config_file(optarg, 1)<   0)
> > > +                    exit(1);
> > > +                break;
> > >                case QEMU_OPTION_writeconfig:
> > >                    {
> > >                        FILE *fp;
> > >
> > >
> > >        
> >      
>
>