qemu-img: add the 'dd' subcommand

This patch adds a basic dd subcommand analogous to dd(1) to qemu-img.

For the start, this implements the bs, if, of and count options and requires
both if and of to be specified (no stdin/stdout if not specified) and doesn't
support tty, pipes, etc.

The image format must be specified with -O for the output if the raw format
is not the intended one.

Two tests are added to test qemu-img dd.

Signed-off-by: Reda Sallahi <fullmanet@gmail.com>
Message-id: 20160810024312.14544-1-fullmanet@gmail.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[mreitz: Moved test 158 to 170]
Signed-off-by: Max Reitz <mreitz@redhat.com>

qemu-img-cmds.hx

@@ -45,6 +45,12 @@ STEXI
 @item convert [--object @var{objectdef}] [--image-opts] [-c] [-p] [-q] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_id_or_name}] [-l @var{snapshot_param}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
 ETEXI
 
+DEF("dd", img_dd,
+    "dd [--image-opts] [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks] if=input of=output")
+STEXI
+@item dd [--image-opts] [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] if=@var{input} of=@var{output}
+ETEXI
+
 DEF("info", img_info,
     "info [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [--backing-chain] filename")
 STEXI

qemu-img.c

@@ -166,7 +166,14 @@ static void QEMU_NORETURN help(void)
            "Parameters to compare subcommand:\n"
            "  '-f' first image format\n"
            "  '-F' second image format\n"
-           "  '-s' run in Strict mode - fail on different image size or sector allocation\n";
+           "  '-s' run in Strict mode - fail on different image size or sector allocation\n"
+           "\n"
+           "Parameters to dd subcommand:\n"
+           "  'bs=BYTES' read and write up to BYTES bytes at a time "
+           "(default: 512)\n"
+           "  'count=N' copy only N input blocks\n"
+           "  'if=FILE' read from FILE\n"
+           "  'of=FILE' write to FILE\n";
 
     printf("%s\nSupported formats:", help_msg);
     bdrv_iterate_format(format_print, NULL);
@@ -3796,6 +3803,300 @@ out:
     return 0;
 }
 
+#define C_BS      01
+#define C_COUNT   02
+#define C_IF      04
+#define C_OF      010
+
+struct DdInfo {
+    unsigned int flags;
+    int64_t count;
+};
+
+struct DdIo {
+    int bsz;    /* Block size */
+    char *filename;
+    uint8_t *buf;
+};
+
+struct DdOpts {
+    const char *name;
+    int (*f)(const char *, struct DdIo *, struct DdIo *, struct DdInfo *);
+    unsigned int flag;
+};
+
+static int img_dd_bs(const char *arg,
+                     struct DdIo *in, struct DdIo *out,
+                     struct DdInfo *dd)
+{
+    char *end;
+    int64_t res;
+
+    res = qemu_strtosz_suffix(arg, &end, QEMU_STRTOSZ_DEFSUFFIX_B);
+
+    if (res <= 0 || res > INT_MAX || *end) {
+        error_report("invalid number: '%s'", arg);
+        return 1;
+    }
+    in->bsz = out->bsz = res;
+
+    return 0;
+}
+
+static int img_dd_count(const char *arg,
+                        struct DdIo *in, struct DdIo *out,
+                        struct DdInfo *dd)
+{
+    char *end;
+
+    dd->count = qemu_strtosz_suffix(arg, &end, QEMU_STRTOSZ_DEFSUFFIX_B);
+
+    if (dd->count < 0 || *end) {
+        error_report("invalid number: '%s'", arg);
+        return 1;
+    }
+
+    return 0;
+}
+
+static int img_dd_if(const char *arg,
+                     struct DdIo *in, struct DdIo *out,
+                     struct DdInfo *dd)
+{
+    in->filename = g_strdup(arg);
+
+    return 0;
+}
+
+static int img_dd_of(const char *arg,
+                     struct DdIo *in, struct DdIo *out,
+                     struct DdInfo *dd)
+{
+    out->filename = g_strdup(arg);
+
+    return 0;
+}
+
+static int img_dd(int argc, char **argv)
+{
+    int ret = 0;
+    char *arg = NULL;
+    char *tmp;
+    BlockDriver *drv = NULL, *proto_drv = NULL;
+    BlockBackend *blk1 = NULL, *blk2 = NULL;
+    QemuOpts *opts = NULL;
+    QemuOptsList *create_opts = NULL;
+    Error *local_err = NULL;
+    bool image_opts = false;
+    int c, i;
+    const char *out_fmt = "raw";
+    const char *fmt = NULL;
+    int64_t size = 0;
+    int64_t block_count = 0, out_pos, in_pos;
+    struct DdInfo dd = {
+        .flags = 0,
+        .count = 0,
+    };
+    struct DdIo in = {
+        .bsz = 512, /* Block size is by default 512 bytes */
+        .filename = NULL,
+        .buf = NULL
+    };
+    struct DdIo out = {
+        .bsz = 512,
+        .filename = NULL,
+        .buf = NULL
+    };
+
+    const struct DdOpts options[] = {
+        { "bs", img_dd_bs, C_BS },
+        { "count", img_dd_count, C_COUNT },
+        { "if", img_dd_if, C_IF },
+        { "of", img_dd_of, C_OF },
+        { NULL, NULL, 0 }
+    };
+    const struct option long_options[] = {
+        { "help", no_argument, 0, 'h'},
+        { "image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
+        { 0, 0, 0, 0 }
+    };
+
+    while ((c = getopt_long(argc, argv, "hf:O:", long_options, NULL))) {
+        if (c == EOF) {
+            break;
+        }
+        switch (c) {
+        case 'O':
+            out_fmt = optarg;
+            break;
+        case 'f':
+            fmt = optarg;
+            break;
+        case '?':
+            error_report("Try 'qemu-img --help' for more information.");
+            ret = -1;
+            goto out;
+        case 'h':
+            help();
+            break;
+        case OPTION_IMAGE_OPTS:
+            image_opts = true;
+            break;
+        }
+    }
+
+    for (i = optind; i < argc; i++) {
+        int j;
+        arg = g_strdup(argv[i]);
+
+        tmp = strchr(arg, '=');
+        if (tmp == NULL) {
+            error_report("unrecognized operand %s", arg);
+            ret = -1;
+            goto out;
+        }
+
+        *tmp++ = '\0';
+
+        for (j = 0; options[j].name != NULL; j++) {
+            if (!strcmp(arg, options[j].name)) {
+                break;
+            }
+        }
+        if (options[j].name == NULL) {
+            error_report("unrecognized operand %s", arg);
+            ret = -1;
+            goto out;
+        }
+
+        if (options[j].f(tmp, &in, &out, &dd) != 0) {
+            ret = -1;
+            goto out;
+        }
+        dd.flags |= options[j].flag;
+        g_free(arg);
+        arg = NULL;
+    }
+
+    if (!(dd.flags & C_IF && dd.flags & C_OF)) {
+        error_report("Must specify both input and output files");
+        ret = -1;
+        goto out;
+    }
+    blk1 = img_open(image_opts, in.filename, fmt, 0, false, false);
+
+    if (!blk1) {
+        ret = -1;
+        goto out;
+    }
+
+    drv = bdrv_find_format(out_fmt);
+    if (!drv) {
+        error_report("Unknown file format");
+        ret = -1;
+        goto out;
+    }
+    proto_drv = bdrv_find_protocol(out.filename, true, &local_err);
+
+    if (!proto_drv) {
+        error_report_err(local_err);
+        ret = -1;
+        goto out;
+    }
+    if (!drv->create_opts) {
+        error_report("Format driver '%s' does not support image creation",
+                     drv->format_name);
+        ret = -1;
+        goto out;
+    }
+    if (!proto_drv->create_opts) {
+        error_report("Protocol driver '%s' does not support image creation",
+                     proto_drv->format_name);
+        ret = -1;
+        goto out;
+    }
+    create_opts = qemu_opts_append(create_opts, drv->create_opts);
+    create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
+
+    opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
+
+    size = blk_getlength(blk1);
+    if (size < 0) {
+        error_report("Failed to get size for '%s'", in.filename);
+        ret = -1;
+        goto out;
+    }
+
+    if (dd.flags & C_COUNT && dd.count <= INT64_MAX / in.bsz &&
+        dd.count * in.bsz < size) {
+        size = dd.count * in.bsz;
+    }
+
+    qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
+
+    ret = bdrv_create(drv, out.filename, opts, &local_err);
+    if (ret < 0) {
+        error_reportf_err(local_err,
+                          "%s: error while creating output image: ",
+                          out.filename);
+        ret = -1;
+        goto out;
+    }
+
+    blk2 = img_open(image_opts, out.filename, out_fmt, BDRV_O_RDWR,
+                    false, false);
+
+    if (!blk2) {
+        ret = -1;
+        goto out;
+    }
+
+    in.buf = g_new(uint8_t, in.bsz);
+
+    for (in_pos = 0, out_pos = 0; in_pos < size; block_count++) {
+        int in_ret, out_ret;
+
+        if (in_pos + in.bsz > size) {
+            in_ret = blk_pread(blk1, in_pos, in.buf, size - in_pos);
+        } else {
+            in_ret = blk_pread(blk1, in_pos, in.buf, in.bsz);
+        }
+        if (in_ret < 0) {
+            error_report("error while reading from input image file: %s",
+                         strerror(-in_ret));
+            ret = -1;
+            goto out;
+        }
+        in_pos += in_ret;
+
+        out_ret = blk_pwrite(blk2, out_pos, in.buf, in_ret, 0);
+
+        if (out_ret < 0) {
+            error_report("error while writing to output image file: %s",
+                         strerror(-out_ret));
+            ret = -1;
+            goto out;
+        }
+        out_pos += out_ret;
+    }
+
+out:
+    g_free(arg);
+    qemu_opts_del(opts);
+    qemu_opts_free(create_opts);
+    blk_unref(blk1);
+    blk_unref(blk2);
+    g_free(in.filename);
+    g_free(out.filename);
+    g_free(in.buf);
+    g_free(out.buf);
+
+    if (ret) {
+        return 1;
+    }
+    return 0;
+}
+
 
 static const img_cmd_t img_cmds[] = {
 #define DEF(option, callback, arg_string)        \

qemu-img.texi

@@ -139,6 +139,20 @@ Parameters to convert subcommand:
 Skip the creation of the target volume
 @end table
 
+Parameters to dd subcommand:
+
+@table @option
+
+@item bs=@var{block_size}
+defines the block size
+@item count=@var{blocks}
+sets the number of input blocks to copy
+@item if=@var{input}
+sets the input file
+@item of=@var{output}
+sets the output file
+@end table
+
 Command description:
 
 @table @option
@@ -310,6 +324,17 @@ skipped. This is useful for formats such as @code{rbd} if the target
 volume has already been created with site specific options that cannot
 be supplied through qemu-img.
 
+@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] if=@var{input} of=@var{output}
+
+Dd copies from @var{input} file to @var{output} file converting it from
+@var{fmt} format to @var{output_fmt} format.
+
+The data is by default read and written using blocks of 512 bytes but can be
+modified by specifying @var{block_size}. If count=@var{blocks} is specified
+dd will stop reading input after reading @var{blocks} input blocks.
+
+The size syntax is similar to dd(1)'s size syntax.
+
 @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}
 
 Give information about the disk image @var{filename}. Use it in

tests/qemu-iotests/159

@@ -0,0 +1,70 @@
+#! /bin/bash
+#
+# qemu-img dd test with different block sizes
+#
+# Copyright (C) 2016 Reda Sallahi
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+owner=fullmanet@gmail.com
+
+seq="$(basename $0)"
+echo "QA output created by $seq"
+
+here="$PWD"
+status=1
+
+_cleanup()
+{
+    _cleanup_test_img
+    rm -f "$TEST_IMG.out"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+. ./common.rc
+. ./common.filter
+. ./common.pattern
+
+_supported_fmt generic
+_supported_proto file
+_supported_os Linux
+
+TEST_SIZES="5 512 1024 1999 1K 64K 1M"
+
+for bs in $TEST_SIZES; do
+    echo
+    echo "== Creating image =="
+
+    size=1M
+    _make_test_img $size
+    _check_test_img
+    $QEMU_IO -c "write -P 0xa 0 $size" "$TEST_IMG" | _filter_qemu_io
+
+    echo
+    echo "== Converting the image with dd with a block size of $bs =="
+
+    $QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" bs=$bs -O "$IMGFMT"
+    TEST_IMG="$TEST_IMG.out" _check_test_img
+
+    echo
+    echo "== Compare the images with qemu-img compare =="
+
+    $QEMU_IMG compare "$TEST_IMG" "$TEST_IMG.out"
+done
+
+echo
+echo "*** done"
+rm -f "$seq.full"
+status=0

tests/qemu-iotests/159.out

@@ -0,0 +1,87 @@
+QA output created by 159
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 5 ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 512 ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 1024 ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 1999 ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 1K ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 64K ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd with a block size of 1M ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+*** done

tests/qemu-iotests/170

@@ -0,0 +1,67 @@
+#! /bin/bash
+#
+# qemu-img dd test
+#
+# Copyright (C) 2016 Reda Sallahi
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+owner=fullmanet@gmail.com
+
+seq="$(basename $0)"
+echo "QA output created by $seq"
+
+here="$PWD"
+status=1
+
+_cleanup()
+{
+    _cleanup_test_img
+    rm -f "$TEST_IMG.out"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+. ./common.rc
+. ./common.filter
+. ./common.pattern
+
+_supported_fmt generic
+_supported_proto file
+_supported_os Linux
+
+echo
+echo "== Creating image =="
+
+size=1M
+_make_test_img $size
+_check_test_img
+
+$QEMU_IO -c "write -P 0xa 0 $size" "$TEST_IMG" | _filter_qemu_io
+
+echo
+echo "== Converting the image with dd =="
+
+$QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" -O "$IMGFMT"
+TEST_IMG="$TEST_IMG.out" _check_test_img
+
+echo
+echo "== Compare the images with qemu-img compare =="
+
+$QEMU_IMG compare "$TEST_IMG" "$TEST_IMG.out"
+
+echo
+echo "*** done"
+rm -f "$seq.full"
+status=0

tests/qemu-iotests/170.out

@@ -0,0 +1,15 @@
+QA output created by 170
+
+== Creating image ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+No errors were found on the image.
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Converting the image with dd ==
+No errors were found on the image.
+
+== Compare the images with qemu-img compare ==
+Images are identical.
+
+*** done

tests/qemu-iotests/common.filter

@@ -44,6 +44,15 @@ _filter_imgfmt()
     sed -e "s#$IMGFMT#IMGFMT#g"
 }
 
+# Replace error message when the format is not supported and delete
+# the output lines after the first one
+_filter_qemu_img_check()
+{
+    sed -e '/allocated.*fragmented.*compressed clusters/d' \
+        -e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
+        -e '/Image end offset: [0-9]\+/d'
+}
+
 # Removes \r from messages
 _filter_win32()
 {

tests/qemu-iotests/common.rc

@@ -234,10 +234,7 @@ _check_test_img()
         else
             $QEMU_IMG check "$@" -f $IMGFMT "$TEST_IMG" 2>&1
         fi
-    ) | _filter_testdir | \
+    ) | _filter_testdir | _filter_qemu_img_check
-        sed -e '/allocated.*fragmented.*compressed clusters/d' \
-            -e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
-            -e '/Image end offset: [0-9]\+/d'
 }
 
 _img_info()

tests/qemu-iotests/group

@@ -157,4 +157,6 @@
 155 rw auto
 156 rw auto quick
 157 auto
+159 rw auto quick
 162 auto quick
+170 rw auto quick