Re: [Qemu-devel] [PATCH V6 2/2] qemu-img: Add json output option to the info command.

["Benoît Canet" <benoit.canet@irqsave.net>]

Thanks for reviewing.
I will correct the series tomorow.

Benoît

Le Tuesday 04 Sep 2012 à 14:54:18 (+0200), Kevin Wolf a écrit :
> Am 27.08.2012 09:15, schrieb Benoît Canet:
> > This option --output=[human|json] make qemu-img info output on
> > human or JSON representation at the choice of the user.
> > 
> > example:
> > {
> >     "snapshots": [
> >         {
> >             "vm-clock-nsec": 637102488,
> >             "name": "vm-20120821145509",
> >             "date-sec": 1345553709,
> >             "date-nsec": 220289000,
> >             "vm-clock-sec": 20,
> >             "id": "1",
> >             "vm-state-size": 96522745
> >         },
> >         {
> >             "vm-clock-nsec": 28210866,
> >             "name": "vm-20120821154059",
> >             "date-sec": 1345556459,
> >             "date-nsec": 171392000,
> >             "vm-clock-sec": 46,
> >             "id": "2",
> >             "vm-state-size": 101208714
> >         }
> >     ],
> >     "virtual-size": 1073741824,
> >     "filename": "snap.qcow2",
> >     "cluster-size": 65536,
> >     "format": "qcow2",
> >     "actual-size": 985587712,
> >     "dirty-flag": false
> > }
> > 
> > Signed-off-by: Benoit Canet <benoit@irqsave.net>
> > ---
> >  Makefile   |    3 +-
> >  qemu-img.c |  259 ++++++++++++++++++++++++++++++++++++++++++++++++++----------
> >  2 files changed, 218 insertions(+), 44 deletions(-)
> > 
> > diff --git a/Makefile b/Makefile
> > index ab82ef3..9ba064b 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -160,7 +160,8 @@ tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
> >  	iohandler.o cutils.o iov.o async.o
> >  tools-obj-$(CONFIG_POSIX) += compatfd.o
> >  
> > -qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y)
> > +qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y) $(qapi-obj-y) \
> > +                              qapi-visit.o qapi-types.o
> >  qemu-nbd$(EXESUF): qemu-nbd.o $(tools-obj-y) $(block-obj-y)
> >  qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
> >  
> > diff --git a/qemu-img.c b/qemu-img.c
> > index 80cfb9b..fe4a4fc 100644
> > --- a/qemu-img.c
> > +++ b/qemu-img.c
> > @@ -21,12 +21,16 @@
> >   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> >   * THE SOFTWARE.
> >   */
> > +#include "qapi-visit.h"
> > +#include "qapi/qmp-output-visitor.h"
> > +#include "qjson.h"
> >  #include "qemu-common.h"
> >  #include "qemu-option.h"
> >  #include "qemu-error.h"
> >  #include "osdep.h"
> >  #include "sysemu.h"
> >  #include "block_int.h"
> > +#include <getopt.h>
> >  #include <stdio.h>
> >  
> >  #ifdef _WIN32
> > @@ -84,6 +88,7 @@ static void help(void)
> >             "  '-p' show progress of command (only certain commands)\n"
> >             "  '-S' indicates the consecutive number of bytes that must contain only zeros\n"
> >             "       for qemu-img to create a sparse image during conversion\n"
> > +           "  '--output' takes the format in which the output must be done (human or json)\n"
> >             "\n"
> >             "Parameters to check subcommand:\n"
> >             "  '-r' tries to repair any inconsistencies that are found during the check.\n"
> 
> qemu-img-cmds.hx and qemu-img.texi should be updated with documentation
> of the new option as well.
> 
> > @@ -1102,21 +1107,196 @@ static void dump_snapshots(BlockDriverState *bs)
> >      g_free(sn_tab);
> >  }
> >  
> > -static int img_info(int argc, char **argv)
> > +static void collect_snapshots(BlockDriverState *bs , ImageInfo *info)
> > +{
> > +    int i, sn_count;
> > +    QEMUSnapshotInfo *sn_tab = NULL;
> > +    SnapshotInfoList *info_list, *cur_item = NULL;
> > +    sn_count = bdrv_snapshot_list(bs, &sn_tab);
> > +
> > +    for (i = 0; i < sn_count; i++) {
> > +        info->has_snapshots = true;
> > +        info_list = g_new0(SnapshotInfoList, 1);
> > +
> > +        info_list->value                = g_new0(SnapshotInfo, 1);
> > +        info_list->value->id            = g_strdup(sn_tab[i].id_str);
> > +        info_list->value->name          = g_strdup(sn_tab[i].name);
> > +        info_list->value->vm_state_size = sn_tab[i].vm_state_size;
> > +        info_list->value->date_sec      = sn_tab[i].date_sec;
> > +        info_list->value->date_nsec     = sn_tab[i].date_nsec;
> > +        info_list->value->vm_clock_sec  = sn_tab[i].vm_clock_nsec / 1000000000;
> > +        info_list->value->vm_clock_nsec = sn_tab[i].vm_clock_nsec % 1000000000;
> > +
> > +        /* XXX: waiting for the qapi to support GSList */
> 
> No, GSList isn't typesafe and therefore to be avoided. If anything, the
> support we want is for qemu-queue.h types.
> 
> > +        if (!cur_item) {
> > +            info->snapshots = cur_item = info_list;
> > +        } else {
> > +            cur_item->next = info_list;
> > +            cur_item = info_list;
> > +        }
> > +
> > +    }
> > +
> > +    g_free(sn_tab);
> > +}
> > +
> > +static void dump_json_image_info(ImageInfo *info)
> > +{
> > +    Error *errp = NULL;
> > +    QString *str;
> > +    QmpOutputVisitor *ov = qmp_output_visitor_new();
> > +    QObject *obj;
> > +    visit_type_ImageInfo(qmp_output_get_visitor(ov),
> > +                         &info, NULL, &errp);
> > +    obj = qmp_output_get_qobject(ov);
> > +    str = qobject_to_json_pretty(obj);
> > +    assert(str != NULL);
> > +    printf("%s\n", qstring_get_str(str));
> > +    qobject_decref(obj);
> > +    qmp_output_visitor_cleanup(ov);
> > +    QDECREF(str);
> > +}
> > +
> > +static void collect_backing_file_format(ImageInfo *info, char *filename)
> > +{
> > +    BlockDriverState *bs = NULL;
> > +    bs = bdrv_new_open(filename, NULL,
> > +                       BDRV_O_FLAGS | BDRV_O_NO_BACKING);
> > +    if (!bs) {
> > +        return;
> > +    }
> > +    info->backing_filename_format =
> > +                    g_strdup(bdrv_get_format_name(bs));
> > +    bdrv_delete(bs);
> > +    info->has_backing_filename_format = true;
> > +}
> 
> This is new functionality and should be added in a separate patch.
> 
> It is also wrong because it uses NULL instead of the explicitly
> specified format to open the image.
> 
> > +
> > +static void collect_image_info(BlockDriverState *bs,
> > +                   ImageInfo *info,
> > +                   const char *filename,
> > +                   const char *fmt)
> >  {
> > -    int c;
> > -    const char *filename, *fmt;
> > -    BlockDriverState *bs;
> > -    char size_buf[128], dsize_buf[128];
> >      uint64_t total_sectors;
> > -    int64_t allocated_size;
> >      char backing_filename[1024];
> >      char backing_filename2[1024];
> >      BlockDriverInfo bdi;
> > +    struct stat st;
> > +
> > +    bdrv_get_geometry(bs, &total_sectors);
> > +
> > +    info->filename        = g_strdup(filename);
> > +    info->format          = g_strdup(bdrv_get_format_name(bs));
> > +    info->virtual_size    = total_sectors * 512;
> > +    info->actual_size     = bdrv_get_allocated_file_size(bs);
> > +    info->has_actual_size = info->actual_size >= 0;
> > +    if (bdrv_is_encrypted(bs)) {
> > +        info->encrypted = true;
> > +        info->has_encrypted = true;
> > +    }
> > +    if (bdrv_get_info(bs, &bdi) >= 0) {
> > +        if (bdi.cluster_size != 0) {
> > +            info->cluster_size = bdi.cluster_size;
> > +            info->has_cluster_size = true;
> > +        }
> > +        if (bdi.is_dirty) {
> > +            info->dirty_flag = true;
> > +        } else {
> > +            info->dirty_flag = false;
> > +        }
> 
> Shorter written as:
> 
> info->dirty_flag = bdi.is_dirty;
> 
> > +        info->has_dirty_flag = true;
> > +    }
> > +    bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
> > +    if (backing_filename[0] != '\0') {
> > +        info->backing_filename = g_strdup(backing_filename);
> > +        info->has_backing_filename = true;
> > +        bdrv_get_full_backing_filename(bs, backing_filename2,
> > +                                       sizeof(backing_filename2));
> > +
> > +        if (strcmp(backing_filename, backing_filename2) != 0) {
> > +            info->full_backing_filename =
> > +                        g_strdup(backing_filename2);
> > +             info->has_full_backing_filename = true;
> > +        }
> > +
> > +        if (access(backing_filename2, R_OK) == 0 &&
> > +            !stat(backing_filename2, &st) &&
> > +            S_ISREG(st.st_mode)) {
> 
> What are you doing here? This is most certainly wrong because it doesn't
> consider protocols supported by qemu.
> 
> Also, I believe what you really want to expose is the backing file
> format as specified in the image file (if any), i.e. bs->backing_format.
> Opening the backing isn't even necessary then.
> 
> > +                collect_backing_file_format(info, backing_filename2);
> > +
> > +        }
> > +    }
> > +}
> > +
> > +static void dump_human_image_info(ImageInfo *info)
> > +{
> > +    char size_buf[128], dsize_buf[128];
> > +    if (!info->has_actual_size) {
> > +        snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");
> > +    } else {
> > +        get_human_readable_size(dsize_buf, sizeof(dsize_buf),
> > +                                info->actual_size);
> > +    }
> > +    get_human_readable_size(size_buf, sizeof(size_buf), info->virtual_size);
> > +    printf("image: %s\n"
> > +           "file format: %s\n"
> > +           "virtual size: %s (%" PRId64 " bytes)\n"
> > +           "disk size: %s\n",
> > +           info->filename, info->format, size_buf,
> > +           info->virtual_size,
> > +           dsize_buf);
> > +
> > +    if (info->has_encrypted && info->encrypted) {
> > +        printf("encrypted: yes\n");
> > +    }
> > +
> > +    if (info->has_cluster_size) {
> > +        printf("cluster_size: %" PRId64 "\n", info->cluster_size);
> > +    }
> > +
> > +    if (info->has_dirty_flag && info->dirty_flag) {
> > +        printf("cleanly shut down: no\n");
> > +    }
> > +
> 
> > +    if (info->has_backing_filename) {
> > +        printf("backing file: %s", info->backing_filename);
> > +    }
> > +
> > +    if (info->has_full_backing_filename) {
> > +        printf(" (actual path: %s)", info->full_backing_filename);
> > +    }
> > +
> > +    if (info->has_backing_filename) {
> > +        putchar('\n');
> > +    }
> 
> The full filename is only present if the "normal" name is present
> (otherwise the output would come out wrong anyway). So:
> 
> if (info->has_backing_filename) {
>     printf("backing file: %s", info->backing_filename);
>     if (info->has_full_backing_filename) {
>        printf(" (actual path: %s)", info->full_backing_filename);
>     }
>     putchar('\n');
> }
> 
> > +}
> > +
> > +enum {OPTION_OUTPUT = 256};
> > +
> > +typedef enum Format {
> > +    FORMAT_JSON,
> > +    FORMAT_HUMAN,
> > +} Format;
> 
> Hm, calling this Format is asking for naming conflicts. Maybe OutputFormat?
> 
> > +
> > +static int img_info(int argc, char **argv)
> > +{
> > +    int c;
> > +    Format output_format;
> 
> Format output_format = FORMAT_HUMAN;
> 
> > +    const char *filename, *fmt, *output;
> > +    BlockDriverState *bs;
> > +    ImageInfo *info;
> >  
> >      fmt = NULL;
> > +    output = NULL;
> >      for(;;) {
> > -        c = getopt(argc, argv, "f:h");
> > +        int option_index = 0;
> > +        static const struct option long_options[] = {
> > +            {"help", no_argument, 0, 'h'},
> > +            {"format", required_argument, 0, 'f'},
> > +            {"output", required_argument, 0, OPTION_OUTPUT},
> > +            {0, 0, 0, 0}
> > +        };
> > +        c = getopt_long(argc, argv, "f:h",
> > +                        long_options, &option_index);
> >          if (c == -1) {
> >              break;
> >          }
> > @@ -1128,6 +1308,9 @@ static int img_info(int argc, char **argv)
> >          case 'f':
> >              fmt = optarg;
> >              break;
> > +        case OPTION_OUTPUT:
> > +            output = optarg;
> > +            break;
> >          }
> >      }
> >      if (optind >= argc) {
> > @@ -1135,48 +1318,38 @@ static int img_info(int argc, char **argv)
> >      }
> >      filename = argv[optind++];
> >  
> > -    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING);
> > -    if (!bs) {
> > +    if (output && !strcmp(output, "json")) {
> > +        output_format = FORMAT_JSON;
> > +    } else if (output && !strcmp(output, "human")) {
> > +        output_format = FORMAT_HUMAN;
> > +    } else if (output) {
> > +        fprintf(stderr,
> > +            "Error: --output must be used with human or json as argument.\n");
> 
> error_report()?
> 
> >          return 1;
> > -    }
> > -    bdrv_get_geometry(bs, &total_sectors);
> > -    get_human_readable_size(size_buf, sizeof(size_buf), total_sectors * 512);
> > -    allocated_size = bdrv_get_allocated_file_size(bs);
> > -    if (allocated_size < 0) {
> > -        snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");
> >      } else {
> > -        get_human_readable_size(dsize_buf, sizeof(dsize_buf),
> > -                                allocated_size);
> > +        output_format = FORMAT_HUMAN;
> >      }
> 
> When you add the default above, you don't need the else branch here.
> 
> > -    printf("image: %s\n"
> > -           "file format: %s\n"
> > -           "virtual size: %s (%" PRId64 " bytes)\n"
> > -           "disk size: %s\n",
> > -           filename, bdrv_get_format_name(bs), size_buf,
> > -           (total_sectors * 512),
> > -           dsize_buf);
> > -    if (bdrv_is_encrypted(bs)) {
> > -        printf("encrypted: yes\n");
> > +
> > +    info = g_new0(ImageInfo, 1);
> > +    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING);
> > +    if (!bs) {
> > +        g_free(info);
> > +        return 1;
> >      }
> > -    if (bdrv_get_info(bs, &bdi) >= 0) {
> > -        if (bdi.cluster_size != 0) {
> > -            printf("cluster_size: %d\n", bdi.cluster_size);
> > -        }
> > -        if (bdi.is_dirty) {
> > -            printf("cleanly shut down: no\n");
> > -        }
> > +
> > +    collect_image_info(bs, info, filename, fmt);
> > +
> > +    if (output_format == FORMAT_HUMAN) {
> > +        dump_human_image_info(info);
> > +        dump_snapshots(bs);
> >      }
> > -    bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
> > -    if (backing_filename[0] != '\0') {
> > -        bdrv_get_full_backing_filename(bs, backing_filename2,
> > -                                       sizeof(backing_filename2));
> > -        printf("backing file: %s", backing_filename);
> > -        if (strcmp(backing_filename, backing_filename2) != 0) {
> > -            printf(" (actual path: %s)", backing_filename2);
> > -        }
> > -        putchar('\n');
> > +
> > +    if (output_format == FORMAT_JSON) {
> > +        collect_snapshots(bs, info);
> > +        dump_json_image_info(info);
> >      }
> 
> Use a switch instead of two independent ifs?
> 
> > -    dump_snapshots(bs);
> > +
> > +    qapi_free_ImageInfo(info);
> >      bdrv_delete(bs);
> >      return 0;
> >  }
> > 
> 
> Kevin