[Qemu-devel] [PATCH 1/6] libqblock APIs

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  This patch contains the major APIs in the library.
Important APIs:
  1 QBroker. These structure was used to retrieve errors, every thread must
create one first, Later maybe thread related staff could be added into it.
  2 QBlockState. It stands for an block image object.
  3 QBlockInfoImageStatic. Now it is not folded with location and format.
  4 ABI was kept with reserved members.

structure, because it would cause caller more codes to find one member.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 libqblock/libqblock.c |  859 +++++++++++++++++++++++++++++++++++++++++++++++++
 libqblock/libqblock.h |  251 ++++++++++++++
 2 files changed, 1110 insertions(+), 0 deletions(-)
 create mode 100644 libqblock/libqblock.c
 create mode 100644 libqblock/libqblock.h

diff --git a/libqblock/libqblock.c b/libqblock/libqblock.c
new file mode 100644
index 0000000..3983802
--- /dev/null
+++ b/libqblock/libqblock.c
@@ -0,0 +1,859 @@
+/*
+ * QEMU block layer library
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Wenchao Xia   <xiawenc@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include <unistd.h>
+#include <stdarg.h>
+
+#include "libqblock.h"
+#include "libqblock-helper.h"
+
+#include "qemu-aio.h"
+
+void libqblock_init(void)
+{
+    bdrv_init();
+    qemu_init_main_loop();
+}
+
+int qb_broker_new(struct QBroker **broker)
+{
+    *broker = FUNC_CALLOC(1, sizeof(struct QBroker));
+    if (*broker == NULL) {
+        return QB_ERR_MEM_ERR;
+    }
+    return 0;
+}
+
+void qb_broker_delete(struct QBroker **broker)
+{
+    CLEAN_FREE(*broker);
+    return;
+}
+
+int qb_state_new(struct QBroker *broker,
+                 struct QBlockState **qbs)
+{
+    *qbs = FUNC_CALLOC(1, sizeof(struct QBlockState));
+    if (*qbs == NULL) {
+        set_broker_err_nomem(broker);
+        return broker->err_ret;
+    }
+    (*qbs)->bdrvs = bdrv_new("hda");
+    if ((*qbs)->bdrvs == NULL) {
+        CLEAN_FREE(*qbs);
+        set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                       "failed to create the driver.");
+        return broker->err_ret;
+    }
+    return 0;
+}
+
+void qb_state_delete(struct QBroker *broker,
+                     struct QBlockState **qbs)
+{
+    CLEAN_FREE((*qbs)->filename);
+    if ((*qbs)->bdrvs != NULL) {
+        bdrv_delete((*qbs)->bdrvs);
+        (*qbs)->bdrvs = NULL;
+    }
+    CLEAN_FREE(*qbs);
+    return;
+}
+
+int qb_ol_new(struct QBroker *broker,
+              struct QBlockOptionLoc **op)
+{
+    *op = FUNC_CALLOC(1, sizeof(struct QBlockOptionLoc));
+    if (*op == NULL) {
+        set_broker_err_nomem(broker);
+        return broker->err_ret;
+    }
+    return 0;
+}
+
+void qb_ol_delete(struct QBroker *broker,
+                  struct QBlockOptionLoc **op)
+{
+    CLEAN_FREE(*op);
+}
+
+int qb_of_new(struct QBroker *broker,
+              struct QBlockOptionFormat **op)
+{
+    *op = FUNC_CALLOC(1, sizeof(struct QBlockOptionFormat));
+    if (*op == NULL) {
+        set_broker_err_nomem(broker);
+        return broker->err_ret;
+    }
+    return 0;
+}
+
+void qb_of_delete(struct QBroker *broker,
+                  struct QBlockOptionFormat **op)
+{
+    CLEAN_FREE(*op);
+}
+
+/* return 0 if every thing is fine */
+static int loc_check_params(struct QBroker *broker,
+                            struct QBlockOptionLoc *loc)
+{
+    broker->err_ret = 0;
+
+    switch (loc->prot_type) {
+    case QB_PROTO_FILE:
+        if (loc->prot_op.o_file.filename == NULL) {
+            set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                           "Filename was not set.");
+            goto out;
+        }
+        if (path_has_protocol(loc->prot_op.o_file.filename) > 0) {
+            set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                           "filename [%s] had protocol.",
+                           loc->prot_op.o_file.filename);
+            goto out;
+        }
+        break;
+    default:
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                       "Protocol type [%d] was not valid.",
+                       loc->prot_type);
+        break;
+    }
+
+ out:
+    return broker->err_ret;
+}
+
+/* translate loc structure to internal filename, returned char* need free,
+ * assuming filename is not NULL. *filename would be set to NULL if no valid
+ * filename found. *filename must be freed later.
+ * return 0 if no error with *filename set.
+ */
+static int loc2filename(struct QBroker *broker,
+                        struct QBlockOptionLoc *loc,
+                        char **filename)
+{
+    broker->err_ret = 0;
+
+    if (*filename != NULL) {
+        CLEAN_FREE(*filename);
+    }
+    switch (loc->prot_type) {
+    case QB_PROTO_FILE:
+        *filename = strdup(loc->prot_op.o_file.filename);
+        if (*filename == NULL) {
+            set_broker_err_nomem(broker);
+        }
+        break;
+    default:
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                 "protocol type [%d] is not supported.",
+                  loc->prot_type);
+        break;
+    }
+
+    return broker->err_ret;
+}
+
+/* translate filename to location, loc->prot_type = NONE if fail, filename
+   must be valid. loc internal char pointer must be freed later.
+ * return 0 if no error.
+ */
+static int filename2loc(struct QBroker *broker,
+                        struct QBlockOptionLoc *loc,
+                        const char *filename)
+{
+    broker->err_ret = 0;
+
+    if (path_has_protocol(filename) > 0) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                     "Filename [%s] had protocol, not supportted now.",
+                     filename);
+        goto out;
+    }
+
+    loc->prot_type = QB_PROTO_FILE;
+    switch (loc->prot_type) {
+    case QB_PROTO_FILE:
+        loc->prot_op.o_file.filename = strdup(filename);
+        if (loc->prot_op.o_file.filename == NULL) {
+            set_broker_err_nomem(broker);
+            goto out;
+        }
+        break;
+    default:
+        break;
+    }
+
+ out:
+    return broker->err_ret;
+}
+
+/* return 0 if OK, or qblock error number */
+static int set_backing_file_options(struct QBroker *broker,
+                                    QEMUOptionParameter *param,
+                                    struct QBlockOptionLoc *loc,
+                                    enum QBlockFormat *fmt)
+{
+    char *backing_filename = NULL;
+    const char *fmtstr_backing = NULL;
+    int ret = 0;
+
+    if (loc == NULL) {
+        goto out;
+    }
+
+    ret = loc2filename(broker, loc, &backing_filename);
+    /* ret can < 0 if loc have not been set, mean user did not specify backing
+       file */
+    if (ret == QB_ERR_MEM_ERR) {
+        goto out;
+    }
+    ret = 0;
+
+    if (backing_filename) {
+        ret = set_option_parameter(param,
+                            BLOCK_OPT_BACKING_FILE, backing_filename);
+        assert(ret == 0);
+        if (fmt == NULL) {
+            goto out;
+        }
+        fmtstr_backing = fmt2str(*fmt);
+        if (fmtstr_backing) {
+            ret = set_option_parameter(param,
+                                BLOCK_OPT_BACKING_FMT, fmtstr_backing);
+            assert(ret == 0);
+        }
+    }
+
+ out:
+    FUNC_FREE(backing_filename);
+    return ret;
+}
+
+int qb_create(struct QBroker *broker,
+              struct QBlockState *qbs,
+              struct QBlockOptionLoc *loc,
+              struct QBlockOptionFormat *fmt,
+              int flag)
+{
+    int ret = 0, bd_ret;
+    char *filename = NULL;
+    BlockDriverState *bs = NULL;
+    BlockDriver *drv = NULL, *backing_drv = NULL;
+    bool tmp_bool;
+
+    const char *fmtstr = NULL, *tmp = NULL;
+    QEMUOptionParameter *param = NULL, *create_options = NULL;
+    QEMUOptionParameter *backing_fmt, *backing_file, *size;
+    struct QBlockOption_fmt_cow *o_cow = NULL;
+    struct QBlockOption_fmt_qed *o_qed = NULL;
+    struct QBlockOption_fmt_qcow *o_qcow = NULL;
+    struct QBlockOption_fmt_qcow2 *o_qcow2 = NULL;
+    struct QBlockOption_fmt_raw *o_raw = NULL;
+    struct QBlockOption_fmt_rbd *o_rbd = NULL;
+    struct QBlockOption_fmt_sheepdog *o_sd = NULL;
+    struct QBlockOption_fmt_vdi *o_vdi = NULL;
+    struct QBlockOption_fmt_vmdk *o_vmdk = NULL;
+    struct QBlockOption_fmt_vpc *o_vpc = NULL;
+
+
+    /* check parameters */
+    if (flag & (~LIBQBLOCK_O_VALID_MASK)) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                           "invalid flag was set.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    if ((loc == NULL) || (qbs == NULL) || (fmt == NULL)) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                          "Got unexpected NULL pointer in parameters.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    ret = loc_check_params(broker, loc);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* internal translate */
+    ret = loc2filename(broker, loc, &filename);
+    if (ret != 0) {
+        goto out;
+    }
+
+    fmtstr = fmt2str(fmt->fmt_type);
+    if (fmtstr == NULL) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                 "Got unexpected NULL pointer in parameters.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    drv = bdrv_find_format(fmtstr);
+    assert(drv != NULL);
+
+    create_options = append_option_parameters(create_options,
+                                              drv->create_options);
+    param = parse_option_parameters("", create_options, param);
+
+    switch (fmt->fmt_type) {
+    case QB_FMT_COW:
+        o_cow = &(fmt->fmt_op.o_cow);
+        bd_ret = set_option_parameter_int(param,
+                                BLOCK_OPT_SIZE, o_cow->virt_size);
+        assert(bd_ret == 0);
+        /* do not need to check loc, it may be not set */
+        ret = set_backing_file_options(broker, param,
+                                       &o_cow->backing_loc, NULL);
+        if (ret != 0) {
+            goto out;
+        }
+        break;
+    case QB_FMT_QED:
+        o_qed = &(fmt->fmt_op.o_qed);
+        bd_ret = set_option_parameter_int(param,
+                                BLOCK_OPT_SIZE, o_qed->virt_size);
+        assert(bd_ret == 0);
+        ret = set_backing_file_options(broker, param,
+                                 &o_qed->backing_loc, &o_qed->backing_fmt);
+        if (ret != 0) {
+            goto out;
+        }
+        bd_ret = set_option_parameter_int(param,
+                                BLOCK_OPT_CLUSTER_SIZE, o_qed->cluster_size);
+        assert(bd_ret == 0);
+        bd_ret = set_option_parameter_int(param,
+                                BLOCK_OPT_TABLE_SIZE, o_qed->table_size);
+        assert(bd_ret == 0);
+        break;
+    case QB_FMT_QCOW:
+        o_qcow = &(fmt->fmt_op.o_qcow);
+        bd_ret = set_option_parameter_int(param,
+                                BLOCK_OPT_SIZE, o_qcow->virt_size);
+        assert(bd_ret == 0);
+        ret = set_backing_file_options(broker, param,
+                                       &o_qcow->backing_loc, NULL);
+        if (ret != 0) {
+            goto out;
+        }
+        tmp = o_qcow->encrypt ? "on" : "off";
+        bd_ret = set_option_parameter(param, BLOCK_OPT_ENCRYPT, tmp);
+        assert(bd_ret == 0);
+        break;
+    case QB_FMT_QCOW2:
+        o_qcow2 = &(fmt->fmt_op.o_qcow2);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_qcow2->virt_size);
+        assert(bd_ret == 0);
+        ret = set_backing_file_options(broker, param,
+                              &o_qcow2->backing_loc, &o_qcow2->backing_fmt);
+        if (ret != 0) {
+            goto out;
+        }
+        tmp = o_qcow2->encrypt ? "on" : "off";
+        bd_ret = set_option_parameter(param, BLOCK_OPT_ENCRYPT, tmp);
+        assert(bd_ret == 0);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_CLUSTER_SIZE, o_qcow2->cluster_size);
+        assert(bd_ret == 0);
+
+        if (o_qcow2->cpt_lv != QBO_FMT_QCOW2_CPT_NONE) {
+            tmp = o_qcow2->cpt_lv == QBO_FMT_QCOW2_CPT_V010 ? "0.10" : "1.1";
+            bd_ret = set_option_parameter(param,
+                              BLOCK_OPT_COMPAT_LEVEL, tmp);
+            assert(bd_ret == 0);
+        }
+
+        if (o_qcow2->pre_mode != QBO_FMT_QCOW2_PREALLOC_NONE) {
+            tmp = o_qcow2->pre_mode == QBO_FMT_QCOW2_PREALLOC_OFF ?
+                                         "off" : "metadata";
+            bd_ret = set_option_parameter(param,
+                              BLOCK_OPT_PREALLOC, tmp);
+            assert(bd_ret == 0);
+        }
+        break;
+
+    case QB_FMT_RAW:
+        o_raw = &(fmt->fmt_op.o_raw);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_raw->virt_size);
+        assert(bd_ret == 0);
+        break;
+    case QB_FMT_RBD:
+        o_rbd = &(fmt->fmt_op.o_rbd);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_rbd->virt_size);
+        assert(bd_ret == 0);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_CLUSTER_SIZE, o_rbd->cluster_size);
+        assert(bd_ret == 0);
+        break;
+    case QB_FMT_SHEEPDOG:
+        o_sd = &(fmt->fmt_op.o_sheepdog);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_sd->virt_size);
+        assert(bd_ret == 0);
+        ret = set_backing_file_options(broker, param,
+                                       &o_sd->backing_loc, NULL);
+        if (ret != 0) {
+            goto out;
+        }
+        if (o_sd->pre_mode != QBO_FMT_SD_PREALLOC_NONE) {
+            tmp = o_sd->pre_mode == QBO_FMT_SD_PREALLOC_OFF ? "off" : "full";
+            bd_ret = set_option_parameter(param,
+                              BLOCK_OPT_PREALLOC, tmp);
+            assert(bd_ret == 0);
+        }
+        break;
+    case QB_FMT_VDI:
+        o_vdi = &(fmt->fmt_op.o_vdi);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_vdi->virt_size);
+        assert(bd_ret == 0);
+        /* following option is not always valid depends on configuration */
+        set_option_parameter_int(param,
+                              BLOCK_OPT_CLUSTER_SIZE, o_vdi->cluster_size);
+        if (o_vdi->pre_mode != QBO_FMT_VDI_PREALLOC_NONE) {
+            tmp_bool = o_sd->pre_mode == QBO_FMT_VDI_PREALLOC_TRUE ?
+                                                     true : false;
+            set_option_parameter_int(param, "static", tmp_bool);
+        }
+        break;
+    case QB_FMT_VMDK:
+        o_vmdk = &(fmt->fmt_op.o_vmdk);
+        bd_ret = set_option_parameter_int(param,
+                              BLOCK_OPT_SIZE, o_vmdk->virt_size);
+        assert(bd_ret == 0);
+        ret = set_backing_file_options(broker, param,
+                                       &o_vmdk->backing_loc, NULL);
+        if (ret != 0) {
+            goto out;
+        }
+
+        if (o_vmdk->cpt_lv != QBO_FMT_VMDK_CPT_NONE) {
+            tmp_bool = o_vmdk->cpt_lv == QBO_FMT_VMDK_CPT_VMDKV6_TRUE ?
+                                                     true : false;
+            bd_ret = set_option_parameter_int(param, BLOCK_OPT_COMPAT6,
+                                                     tmp_bool);
+            assert(bd_ret == 0);
+        }
+        if (o_vmdk->subfmt != QBO_FMT_VMDK_SUBFMT_MONOLITHIC_NONE) {
+            switch (o_vmdk->subfmt) {
+            case QBO_FMT_VMDK_SUBFMT_MONOLITHIC_SPARSE:
+                tmp = "monolithicSparse";
+                break;
+            case QBO_FMT_VMDK_SUBFMT_MONOLITHIC_FLAT:
+                tmp = "monolithicFlat";
+                break;
+            case QBO_FMT_VMDK_SUBFMT_TWOGBMAX_EXTENT_SPARSE:
+                tmp = "twoGbMaxExtentSparse";
+                break;
+            case QBO_FMT_VMDK_SUBFMT_TWOGBMAX_EXTENT_FLAT:
+                tmp = "twoGbMaxExtentFlat";
+                break;
+            case QBO_FMT_VMDK_SUBFMT_STREAM_OPTIMIZED:
+                tmp = "streamOptimized";
+                break;
+            default:
+                assert(false);
+                break;
+            }
+            bd_ret = set_option_parameter(param,
+                              BLOCK_OPT_SUBFMT, tmp);
+            assert(bd_ret == 0);
+        }
+        break;
+    case QB_FMT_VPC:
+        o_vpc = &(fmt->fmt_op.o_vpc);
+        bd_ret = set_option_parameter_int(param,
+                               BLOCK_OPT_SIZE, o_vpc->virt_size);
+        assert(bd_ret == 0);
+        if (o_vpc->subfmt != QBO_FMT_VPC_SUBFMT_NONE) {
+            tmp = o_vpc->subfmt == QBO_FMT_VPC_SUBFMT_DYNAMIC ?
+                                               "dynamic" : "fixed";
+            bd_ret = set_option_parameter(param,
+                               BLOCK_OPT_SUBFMT, tmp);
+            assert(bd_ret == 0);
+        }
+        break;
+    default:
+        assert(false);
+        break;
+    }
+
+    backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
+    if (backing_file && backing_file->value.s) {
+        if (!strcmp(filename, backing_file->value.s)) {
+            set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                          "Backing file is the same with new file.");
+            ret = broker->err_ret;
+            goto out;
+        }
+    }
+
+    backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
+    if (backing_fmt && backing_fmt->value.s) {
+        backing_drv = bdrv_find_format(backing_fmt->value.s);
+        assert(backing_drv != NULL);
+    }
+
+    size = get_option_parameter(param, BLOCK_OPT_SIZE);
+    if (size && size->value.n <= 0) {
+        if (backing_file && backing_file->value.s) {
+            uint64_t size;
+            char buf[32];
+            int back_flags;
+
+            /* backing files always opened read-only */
+            back_flags =
+                flag &
+                ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
+
+            bs = bdrv_new("");
+
+            ret = bdrv_open(bs, backing_file->value.s,
+                                back_flags, backing_drv);
+            if (ret < 0) {
+                set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                               "Failed to open the backing file.");
+                ret = broker->err_ret;
+                goto out;
+            }
+            bdrv_get_geometry(bs, &size);
+            size *= SECTOR_SIZE;
+
+            snprintf(buf, sizeof(buf), "%" PRId64, size);
+            set_option_parameter(param, BLOCK_OPT_SIZE, buf);
+        } else {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                           "Neither size or backing file was not set.");
+            ret = broker->err_ret;
+            goto out;
+        }
+    }
+
+    bd_ret = bdrv_create(drv, filename, param);
+
+
+    if (bd_ret < 0) {
+        const char *errstr;
+        if (bd_ret == -ENOTSUP) {
+            errstr = "formatting option not supported.";
+        } else if (bd_ret == -EFBIG) {
+            errstr = "The image size is too large.";
+        } else {
+            errstr = "Error in creating the image.";
+        }
+        set_broker_err(broker, QB_ERR_INTERNAL_ERR, errstr);
+        ret = broker->err_ret;
+    }
+
+out:
+    free_option_parameters(create_options);
+    free_option_parameters(param);
+    FUNC_FREE(filename);
+    if (bs) {
+        bdrv_delete(bs);
+    }
+
+    return ret;
+}
+
+int qb_open(struct QBroker *broker,
+            struct QBlockState *qbs,
+            struct QBlockOptionLoc *loc,
+            struct QBlockOptionFormat *fmt,
+            int flag)
+{
+    int ret = 0, bd_ret;
+    BlockDriverState *bs;
+    BlockDriver *bd;
+    const char *fmtstr;
+    char *filename = NULL;
+
+    /* take care of user settings */
+    /* do nothing now */
+
+    /* check parameters */
+    if (flag & (~LIBQBLOCK_O_VALID_MASK)) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                      "Invalid flag was set.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    if ((loc == NULL) || (qbs == NULL)) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                      "Got unexpected NULL pointer in parameters.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    ret = loc_check_params(broker, loc);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* internal translate */
+    ret = loc2filename(broker, loc, &filename);
+    if (ret != 0) {
+        goto out;
+    }
+
+    fmtstr = NULL;
+    bd = NULL;
+    if (fmt != NULL) {
+        fmtstr = fmt2str(fmt->fmt_type);
+    }
+
+    if (fmtstr != NULL) {
+        bd = bdrv_find_format(fmtstr);
+        assert(bd != NULL);
+    }
+
+    /* do real openning */
+    bs = qbs->bdrvs;
+    bd_ret = bdrv_open(bs, filename, flag, bd);
+    if (bd_ret < 0) {
+        set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                      "Failed in opening with driver, bd_ret is %d.", bd_ret);
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    if (qbs->filename != NULL) {
+        FUNC_FREE(qbs->filename);
+    }
+    qbs->filename = strdup(filename);
+    if (qbs->filename == NULL) {
+        set_broker_err_nomem(broker);
+        ret = broker->err_ret;
+        bdrv_close(bs);
+        goto out;
+    }
+
+ out:
+    FUNC_FREE(filename);
+    return ret;
+}
+
+void qb_close(struct QBroker *broker,
+              struct QBlockState *qbs)
+{
+    BlockDriverState *bs;
+
+    bs = qbs->bdrvs;
+
+    if (qbs->filename != NULL) {
+        CLEAN_FREE(qbs->filename);
+        bdrv_close(bs);
+    }
+    return;
+}
+
+int qb_read(struct QBroker *broker,
+            struct QBlockState *qbs,
+            const void *buf,
+            size_t len,
+            off_t offset)
+{
+    int bd_ret;
+    BlockDriverState *bs;
+
+    broker->err_ret = 0;
+    bs = qbs->bdrvs;
+
+    assert((len & SECTOR_SIZE_MASK) == 0);
+    assert((offset & SECTOR_SIZE_MASK) == 0);
+    bd_ret = bdrv_read(bs, offset >> SECTOR_SIZE_BITS_NUM,
+                       (uint8_t *)buf, len >> SECTOR_SIZE_BITS_NUM);
+    if (bd_ret < 0) {
+        if (bd_ret == -EIO) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                           "Generic I/O error.");
+        } else if (bd_ret == -ENOMEDIUM) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                           "No meida inserted.");
+        } else if (bd_ret == -EINVAL) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                          "Sector was not correct.");
+        } else {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                          "Internal error.");
+        }
+    }
+    return broker->err_ret;
+}
+
+int qb_write(struct QBroker *broker,
+            struct QBlockState *qbs,
+            const void *buf,
+            size_t len,
+            off_t offset)
+{
+    int bd_ret;
+    BlockDriverState *bs;
+
+    broker->err_ret = 0;
+    bs = qbs->bdrvs;
+
+    assert((len & SECTOR_SIZE_MASK) == 0);
+    assert((offset & SECTOR_SIZE_MASK) == 0);
+    bd_ret = bdrv_write(bs, offset >> SECTOR_SIZE_BITS_NUM,
+                       (uint8_t *)buf, len >> SECTOR_SIZE_BITS_NUM);
+    if (bd_ret < 0) {
+        if (bd_ret == -EIO) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                           "Generic I/O error.");
+        } else if (bd_ret == -ENOMEDIUM) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                           "No meida inserted.");
+        } else if (bd_ret == -EINVAL) {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                          "Sector was not correct.");
+        } else {
+            set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                          "Internal error.");
+        }
+    }
+    return broker->err_ret;
+}
+
+int qb_flush(struct QBroker *broker,
+             struct QBlockState *qbs)
+{
+    int bd_ret;
+    BlockDriverState *bs;
+
+    broker->err_ret = 0;
+    bs = qbs->bdrvs;
+    bd_ret = bdrv_flush(bs);
+    if (bd_ret < 0) {
+        set_broker_err(broker, QB_ERR_INTERNAL_ERR,
+                       "Internal error.");
+    }
+    return broker->err_ret;
+}
+
+int qb_is_allocated(struct QBroker *broker,
+                    struct QBlockState *qbs,
+                    int64_t sector_num,
+                    int nb_sectors,
+                    int *pnum)
+{
+    int ret;
+    BlockDriverState *bs;
+
+    broker->err_ret = 0;
+    bs = qbs->bdrvs;
+
+    if (qbs->filename == NULL) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                       "Image was not opened first.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    ret = bdrv_is_allocated(bs, sector_num, nb_sectors, pnum);
+
+ out:
+    return ret;
+}
+
+int qb_info_image_static_get(struct QBroker *broker,
+                             struct QBlockState *qbs,
+                             struct QBlockInfoImageStatic **info)
+{
+    int ret = 0;
+    BlockDriverState *bs;
+    struct QBlockInfoImageStatic *info_tmp;
+    const char *fmt_str;
+    size_t total_sectors;
+    char backing_filename[1024];
+
+    if (qbs->filename == NULL) {
+        set_broker_err(broker, QB_ERR_INVALID_PARAM,
+                       "Block Image was not openned.");
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    info_tmp = FUNC_CALLOC(1, sizeof(struct QBlockInfoImageStatic));
+    if (info_tmp == NULL) {
+        set_broker_err_nomem(broker);
+        ret = broker->err_ret;
+        goto out;
+    }
+
+    bs = qbs->bdrvs;
+
+    ret = filename2loc(broker,
+                       &(info_tmp->loc),
+                       qbs->filename);
+    if (ret < 0) {
+        goto free;
+    }
+
+    fmt_str = bdrv_get_format_name(bs);
+    info_tmp->fmt_type = str2fmt(fmt_str);
+
+    bdrv_get_geometry(bs, &total_sectors);
+    info_tmp->virt_size = total_sectors * SECTOR_SIZE;
+
+    info_tmp->allocated_size = bdrv_get_allocated_file_size(bs);
+    info_tmp->encrypt = bdrv_is_encrypted(bs);
+
+    bdrv_get_full_backing_filename(bs, backing_filename,
+                                   sizeof(backing_filename));
+    if (backing_filename[0] != '\0') {
+        ret = filename2loc(broker,
+                           &(info_tmp->backing_loc),
+                           backing_filename);
+        if (ret < 0) {
+            goto free;
+        }
+    }
+
+    *info = info_tmp;
+
+ out:
+    return ret;
+ free:
+    qb_info_image_static_delete(broker, &info_tmp);
+    return ret;
+}
+
+/* free locations if it has string allocated on heap. */
+static void loc_free(struct QBlockOptionLoc *loc)
+{
+    switch (loc->prot_type) {
+    case QB_PROTO_FILE:
+        CLEAN_FREE(loc->prot_op.o_file.filename);
+        break;
+    default:
+        break;
+    }
+}
+
+void qb_info_image_static_delete(struct QBroker *broker,
+                                 struct QBlockInfoImageStatic **info)
+{
+    loc_free(&(*info)->loc);
+    loc_free(&(*info)->backing_loc);
+
+    CLEAN_FREE(*info);
+}
diff --git a/libqblock/libqblock.h b/libqblock/libqblock.h
new file mode 100644
index 0000000..e64e1fd
--- /dev/null
+++ b/libqblock/libqblock.h
@@ -0,0 +1,251 @@
+/*
+ * QEMU block layer library
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Wenchao Xia   <xiawenc@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef LIBQBLOCK_H
+#define LIBQBLOCK_H
+
+#include "libqblock-types.h"
+#include "libqblock-error.h"
+
+
+/**
+ * libqblock_init: Initialize the library
+ */
+void libqblock_init(void);
+
+/**
+ * qb_broker_new: allocate a new broker
+ *
+ * Broker is used to pass operation to libqblock, and got feed back from it.
+ *
+ * Returns 0 on success, negative value on fail.
+ *
+ * @broker: used to receive the created struct.
+ */
+int qb_broker_new(struct QBroker **broker);
+
+/**
+ * qb_broker_delete: delete broker
+ *
+ * Broker will be freed and set to NULL.
+ *
+ * @broker: operation broker to be deleted.
+ */
+void qb_broker_delete(struct QBroker **broker);
+
+/**
+ * qb_state_new: allocate a new QBloctState struct
+ *
+ * Following qblock action were based on this struct
+ *
+ * Returns 0 if succeed, negative value on fail.
+ *
+ * @broker: operation broker.
+ * @qbs: used to receive the created struct.
+ */
+int qb_state_new(struct QBroker *broker,
+                 struct QBlockState **qbs);
+
+/**
+ * qb_state_delete: free a QBloctState struct
+ *
+ * if it is opened, a qb_close must be called before free.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to the struct's pointer.
+ */
+void qb_state_delete(struct QBroker *broker,
+                     struct QBlockState **qbs);
+
+/**
+ * qb_ol_new: create a new struct QBlockOptionLoc.
+ *
+ * return 0 on success, negative on fail.
+ *
+ * @broker: operation broker.
+ * @op: pointer to receive the new created one.
+ */
+int qb_ol_new(struct QBroker *broker,
+              struct QBlockOptionLoc **op);
+
+/**
+ * qb_ol_delete: free a struct QBlockOptionLoc.
+ *
+ * @broker: operation broker.
+ * @op: pointer to the object, *op would be set to NULL.
+ */
+void qb_ol_delete(struct QBroker *broker,
+                  struct QBlockOptionLoc **op);
+
+/**
+ * qb_of_new: create a new QBlockOptionFormat structure.
+ *
+ * return 0 on success, negative on fail.
+ *
+ * @broker: operation broker.
+ * @op: pointer that will receive created struct.
+ */
+int qb_of_new(struct QBroker *broker,
+              struct QBlockOptionFormat **op);
+
+/**
+ * qb_of_delete: free QBlockOptionFormat structure.
+ *
+ * @broker: operation broker.
+ * @op: pointer to the struct, *op would be set to NULL.
+ */
+void qb_of_delete(struct QBroker *broker,
+                  struct QBlockOptionFormat **op);
+
+
+/**
+ * qb_open: open a block object.
+ *
+ * return 0 on success, negative on fail.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @loc: location options for open, how to find the image.
+ * @fmt: format options, how to extract the data, only valid member now is
+     fmt->fmt_type, set NULL if you want auto discovery the format.
+ * @flag: behavior control flags.
+ */
+int qb_open(struct QBroker *broker,
+            struct QBlockState *qbs,
+            struct QBlockOptionLoc *loc,
+            struct QBlockOptionFormat *fmt,
+            int flag);
+
+/**
+ * qb_close: close a block object.
+ *
+ * qb_flush is automaticlly done inside.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ */
+void qb_close(struct QBroker *broker,
+              struct QBlockState *qbs);
+
+/**
+ * qb_create: create a block image or object.
+ *
+ * Note: Create operation would not open the image automatically.
+ *
+ * return negative on fail, 0 on success.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @loc: location options for open, how to find the image.
+ * @fmt: format options, how to extract the data.
+ * @flag: behavior control flags.
+ */
+int qb_create(struct QBroker *broker,
+              struct QBlockState *qbs,
+              struct QBlockOptionLoc *loc,
+              struct QBlockOptionFormat *fmt,
+              int flag);
+
+
+/* sync access */
+/**
+ * qb_read: block sync read.
+ *
+ * return negative on fail, 0 on success.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @buf: buffer that receive the content.
+ * @len: length to read.
+ * @offset: offset in the block data.
+ */
+int qb_read(struct QBroker *broker,
+            struct QBlockState *qbs,
+            const void *buf,
+            size_t len,
+            off_t offset);
+/**
+ * qb_write: block sync write.
+ *
+ * return negative on fail, 0 on success.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @buf: buffer that receive the content.
+ * @len: length to write.
+ * @offset: offset in the block data.
+ */
+int qb_write(struct QBroker *broker,
+             struct QBlockState *qbs,
+             const void *buf,
+             size_t len,
+             off_t offset);
+
+/**
+ * qb_flush: block sync flush.
+ *
+ * return negative on fail, 0 on success.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ */
+int qb_flush(struct QBroker *broker,
+             struct QBlockState *qbs);
+
+
+/* advance image APIs */
+/**
+ * qb_is_allocated: check if following sectors was allocated on the image.
+ *
+ * return negative on fail, 0 or 1 on success. 0 means unallocated, 1 means
+ *allocated.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @sector_num: start sector number. If 'sector_num' is beyond the end of the
+ *disk image the return value is 0 and 'pnum' is set to 0.
+ * @nb_sectors: how many sector would be checked, it is the max value 'pnum'
+ *should be set to.  If nb_sectors goes beyond the end of the disk image it
+ *will be clamped.
+ * @pnum: pointer to receive how many sectors are allocated or unallocated.
+ */
+int qb_is_allocated(struct QBroker *broker,
+                    struct QBlockState *qbs,
+                    int64_t sector_num,
+                    int nb_sectors,
+                    int *pnum);
+
+/* image information */
+/**
+ * qb_get_image_info: get image info.
+ *
+ * return negative on fail, 0 on success.
+ *
+ * @broker: operation broker.
+ * @qbs: pointer to struct QBlockState.
+ * @info: pointer that would receive the information.
+ */
+int qb_info_image_static_get(struct QBroker *broker,
+                             struct QBlockState *qbs,
+                             struct QBlockInfoImageStatic **info);
+
+/**
+ * qb_delete_image_info: free image info.
+ *
+ * @broker: operation broker.
+ * @info: pointer to the information struct.
+ */
+void qb_info_image_static_delete(struct QBroker *broker,
+                                 struct QBlockInfoImageStatic **info);
+
+#endif
-- 
1.7.1