[Qemu-devel] [PATCH 3/3] qemu-img: Add json output option to the info command.

[Benoît Canet]

This additionnal --machine=json option make qemu-img info output on
stdout a JSON formated representation of the image informations.

--machine=json was choosen instead of --format=json because the
info command already have a -f parameter.

example:
{
    "snapshots": [
        {
            "name": "truc",
            "date-sec": 1345034924,
            "date-nsec": 870405000,
            "vm-clock-sec": 4647590161,
            "id": "1",
            "vm-state-size": 80805256
        },
        {
            "name": "onx",
            "date-sec": 1345034927,
            "date-nsec": 914633000,
            "vm-clock-sec": 7065282574,
            "id": "2",
            "vm-state-size": 75927370
        },
        {
            "name": "list",
            "date-sec": 1345034939,
            "date-nsec": 39119000,
            "vm-clock-sec": 10108695046,
            "id": "3",
            "vm-state-size": 75890567
        }
    ],
    "virtual-size": 1073741824,
    "filename": "snapshot.img",
    "cluster-size": 65536,
    "format": "qcow2",
    "actual-size": 242614272,
    "encrypted": false,
    "backing-filename": "truc5.raw",
    "dirty-flag": false
}

Signed-off-by: Benoit Canet <address@hidden>
---
 Makefile   |    3 +-
 qemu-img.c |  126 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 118 insertions(+), 11 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..1a80414 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"
+           "  '-m' or '--machine' takes the format in which the output must be 
done (json)\n"
            "\n"
            "Parameters to check subcommand:\n"
            "  '-r' tries to repair any inconsistencies that are found during 
the check.\n"
@@ -1102,10 +1107,66 @@ static void dump_snapshots(BlockDriverState *bs)
     g_free(sn_tab);
 }
 
+static void collect_snapshots(BlockDriverState *bs , ImageInfo *image_info)
+{
+    int i, sn_count;
+    QEMUSnapshotInfo *sn_tab;
+    SnapshotInfoList *sn_info_list, *cur_item = NULL, *head = NULL;
+    sn_count = bdrv_snapshot_list(bs, &sn_tab);
+
+    for (i = 0; i < sn_count; i++) {
+        sn_info_list = g_new0(SnapshotInfoList, 1);
+
+        sn_info_list->value = g_new0(SnapshotInfo, 1);
+        sn_info_list->value->id = g_strdup(sn_tab[i].id_str);
+        sn_info_list->value->name = g_strdup(sn_tab[i].name);
+        sn_info_list->value->vm_state_size = sn_tab[i].vm_state_size;
+        sn_info_list->value->date_sec = sn_tab[i].date_sec;
+        sn_info_list->value->date_nsec = sn_tab[i].date_nsec;
+        sn_info_list->value->vm_clock_sec = sn_tab[i].vm_clock_nsec;
+
+        /* XXX: waiting for the qapi to support GSList */
+        if (!cur_item) {
+            head = cur_item = sn_info_list;
+        } else {
+            cur_item->next = sn_info_list;
+            cur_item = sn_info_list;
+        }
+
+    }
+
+    g_free(sn_tab);
+    image_info->snapshots = head;
+}
+
+static void dump_json_image_info(ImageInfo *image_info)
+{
+    Error *errp = NULL;
+    QString *str;
+    QmpOutputVisitor *ov = qmp_output_visitor_new();
+    QObject *obj;
+    visit_type_ImageInfo(qmp_output_get_visitor(ov),
+                         &image_info, NULL, &errp);
+    obj = qmp_output_get_qobject(ov);
+    str = qobject_to_json_pretty(obj);
+    assert(str != NULL);
+    qstring_append_chr(str, '\n');
+    printf("%s", qstring_get_str(str));
+    qobject_decref(obj);
+    qmp_output_visitor_cleanup(ov);
+    QDECREF(str);
+}
+
+#define PRINTH(human, args...) do { \
+    if (human) {                    \
+        printf(args);               \
+    } } while (0);
+
 static int img_info(int argc, char **argv)
 {
     int c;
-    const char *filename, *fmt;
+    bool human = true;
+    const char *filename, *fmt, *machine;
     BlockDriverState *bs;
     char size_buf[128], dsize_buf[128];
     uint64_t total_sectors;
@@ -1113,10 +1174,20 @@ static int img_info(int argc, char **argv)
     char backing_filename[1024];
     char backing_filename2[1024];
     BlockDriverInfo bdi;
+    ImageInfo *image_info;
 
     fmt = NULL;
+    machine = NULL;
     for(;;) {
-        c = getopt(argc, argv, "f:h");
+        int option_index = 0;
+        static struct option long_options[] = {
+            {"help", no_argument, 0, 'h'},
+            {"format", required_argument, 0, 'f'},
+            {"machine", required_argument, 0, 'm'},
+            {0, 0, 0, 0}
+        };
+        c = getopt_long(argc, argv, "f:h",
+                        long_options, &option_index);
         if (c == -1) {
             break;
         }
@@ -1128,6 +1199,9 @@ static int img_info(int argc, char **argv)
         case 'f':
             fmt = optarg;
             break;
+        case 'm':
+            machine = optarg;
+            break;
         }
     }
     if (optind >= argc) {
@@ -1135,6 +1209,11 @@ static int img_info(int argc, char **argv)
     }
     filename = argv[optind++];
 
+    image_info = g_new0(ImageInfo, 1);
+    if (machine && !strncmp(machine, "json", strlen("json"))) {
+        human = false;
+    }
+
     bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING);
     if (!bs) {
         return 1;
@@ -1148,39 +1227,66 @@ static int img_info(int argc, char **argv)
         get_human_readable_size(dsize_buf, sizeof(dsize_buf),
                                 allocated_size);
     }
-    printf("image: %s\n"
+    PRINTH(human, "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);
+    image_info->filename = g_strdup(filename);
+    image_info->format = g_strdup(bdrv_get_format_name(bs));
+    image_info->virtual_size = total_sectors * 512;
+    image_info->actual_size = allocated_size >= 0 ? allocated_size : 0;
     if (bdrv_is_encrypted(bs)) {
-        printf("encrypted: yes\n");
+        PRINTH(human, "encrypted: yes\n");
+        image_info->encrypted = true;
+    } else {
+        image_info->encrypted = false;
     }
     if (bdrv_get_info(bs, &bdi) >= 0) {
         if (bdi.cluster_size != 0) {
-            printf("cluster_size: %d\n", bdi.cluster_size);
+            PRINTH(human, "cluster_size: %d\n", bdi.cluster_size);
+            image_info->cluster_size = bdi.cluster_size;
         }
         if (bdi.is_dirty) {
-            printf("cleanly shut down: no\n");
+            PRINTH(human, "cleanly shut down: no\n");
+            image_info->dirty_flag = true;
+        } else {
+            image_info->dirty_flag = false;
         }
     }
     bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
     if (backing_filename[0] != '\0') {
+        image_info->backing_filename = g_strdup(backing_filename);
         bdrv_get_full_backing_filename(bs, backing_filename2,
                                        sizeof(backing_filename2));
-        printf("backing file: %s", backing_filename);
+        PRINTH(human, "backing file: %s", backing_filename);
         if (strcmp(backing_filename, backing_filename2) != 0) {
-            printf(" (actual path: %s)", backing_filename2);
+            PRINTH(human, " (actual path: %s)", backing_filename2);
+        }
+        if (human) {
+            putchar('\n');
         }
-        putchar('\n');
     }
-    dump_snapshots(bs);
+
+    if (human) {
+        dump_snapshots(bs);
+    } else {
+        collect_snapshots(bs, image_info);
+    }
+
+    if (!human) {
+        dump_json_image_info(image_info);
+    }
+
+    qapi_free_ImageInfo(image_info);
     bdrv_delete(bs);
     return 0;
 }
 
+#undef PRINTH
+
 #define SNAPSHOT_LIST   1
 #define SNAPSHOT_CREATE 2
 #define SNAPSHOT_APPLY  3
-- 
1.7.9.5