mirror of
https://github.com/libguestfs/libguestfs.git
synced 2026-03-21 22:53:37 +00:00
0306c98d31
guestfsd calls many different tools. Keeping track of all of them is error prone. This patch introduces a new helper macro to put the command string into its own ELF section: GUESTFSD_EXT_CMD(C_variable, command_name); This syntax makes it still possible to grep for used command names. The actual usage of the collected list could be like this: objcopy -j .guestfsd_ext_cmds -O binary daemon/guestfsd /dev/stdout | tr '\0' '\n' | sort -u The resulting output will be used to tell mkinitrd which programs to copy into the initrd. Signed-off-by: Olaf Hering <olaf@aepfle.de> RWMJ: - Move str_vgchange at request of author. - Fix snprintf call in daemon/debug.c
402 lines
13 KiB
HTML
402 lines
13 KiB
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<!DOCTYPE html>
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
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<title>Short introduction to libguestfs</title>
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body > p, body > img, body > pre, body > table {
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h1 {
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author {
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counter-reset: section;
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h2:before {
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color: #666;
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content: counter(chapter) " ... ";
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}
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pre {
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background-color: #fcfcfc;
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border-top: 1px dotted #eee;
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border-bottom: 1px dotted #eee;
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border-left: 2px solid rgb(204,0,0);
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padding: 5px;
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margin-left: 1em;
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}
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p.sourcelnk {
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text-align: left;
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font-size: 70%;
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}
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</style>
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</head>
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<body>
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<h1>Short introduction to libguestfs</h1>
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<author>by Richard W.M. Jones <rjones@redhat.com></author>
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<h2>The Idea</h2>
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<p><b>Reuse qemu, Linux kernel and userspace tools</b> to read and
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write disk images.</p>
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<object type="image/svg+xml" data="overview.svg">
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<img src="overview.png"/> <!-- fallback for lame IE -->
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</object>
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<h2>The Stable API</h2>
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<pre>
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/* get the Linux VFS type corresponding to a mounted device */
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extern char *<b>guestfs_vfs_type</b> (guestfs_h *g, const char *device);
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</pre>
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<table style="margin-bottom: 4em;" width="100%">
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<tr><td valign="top">Example using this API:</td><td>
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<pre>
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#include <guestfs.h>
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char *fstype = <b>guestfs_vfs_type (g, "/dev/vda1")</b>;
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printf ("%s\n", fstype);
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free (fstype);
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→ <b>ntfs</b>
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</pre>
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<p class="sourcelnk"><a href="http://git.annexia.org/?p=libguestfs.git;a=blob;f=fish/inspect.c;h=2ca54d2296fce5370504c1085cbcd7ac1b51ad3a;hb=HEAD#l208">click to see a real example ...</a></p>
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</td>
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</tr>
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</table>
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<table width="100%">
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<tr><td valign="top">
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<pre>
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("<b>vfs_type</b>",
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(RString "fstype",
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[Device "device"], []),
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198, [],
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[ (* tests *) ],
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"get the Linux VFS type corresponding to a mounted device",
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"\
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This command gets the filesystem type corresponding to
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the filesystem on C<device>.
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For most filesystems, the result is the name of the Linux
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VFS module which would be used to mount this filesystem
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if you mounted it without specifying the filesystem type.
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For example a string such as C<ext3> or C<ntfs>.");
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</pre>
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<p class="sourcelnk"><a href="http://git.annexia.org/?p=libguestfs.git;a=blob;f=generator/generator_actions.ml;h=d3fa3e0b939eb047a5ff103a68f09c6898807748;hb=HEAD#l4775">full source ...</a></p>
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</td>
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<td valign="top">
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<pre>
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char *
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<b>do_vfs_type</b> (const char *device)
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{
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return get_blkid_tag (device, "TYPE");
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}
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GUESTFSD_EXT_CMD(str_blkid, blkid);
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static char *
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get_blkid_tag (const char *device, const char *tag)
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{
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char *out, *err;
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int r;
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r = commandr (&out, &err,
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str_blkid,
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"-c", "/dev/null",
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"-o", "value", "-s", tag, device, NULL);
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if (r != 0 && r != 2) {
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if (r >= 0)
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reply_with_error ("%s: %s (blkid returned %d)",
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device, err, r);
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else
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reply_with_error ("%s: %s", device, err);
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free (out);
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free (err);
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return NULL;
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}
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/* ... */
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return out; /* caller frees */
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}
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</pre>
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<p class="sourcelnk"><a href="http://git.annexia.org/?p=libguestfs.git;a=blob;f=daemon/blkid.c;hb=HEAD">full source ...</a></p>
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</td>
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</tr>
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</table>
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<p>
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Just these two fragments generate:
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</p>
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<ul>
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<li> bindings in <a href="http://libguestfs.org/guestfs.3.html#api_overview">C</a>,
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<a href="http://libguestfs.org/guestfs-perl.3.html">Perl</a>,
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<a href="http://libguestfs.org/guestfs-python.3.html">Python</a>,
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<a href="http://libguestfs.org/guestfs-ruby.3.html">Ruby</a>,
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<a href="http://libguestfs.org/guestfs-java.3.html">Java</a>,
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<a href="http://libguestfs.org/guestfs-ocaml.3.html">OCaml</a>,
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PHP,
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Haskell,
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<a href="http://libguestfs.org/guestfs-erlang.3.html">Erlang</a>
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and C# </li>
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<li> <a href="http://libguestfs.org/guestfish.1.html">guestfish</a>
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(shell script) </li>
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<li> documentation in man pages and HTML </li>
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<li> internal RPC code </li>
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</ul>
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<h2>Tools written around the API</h2>
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<object type="image/svg+xml" data="tools.svg">
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<img src="tools.png"/> <!-- fallback for lame IE -->
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</object>
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<table>
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<tr><td valign="top" style="padding-bottom: 1.5em;" colspan="2">
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<pre>
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<b>guestfish -N bootrootlv:/dev/VG/LV:ext4:ext4:10G:256M <<EOF</b>
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<font style="color: green;">mount /dev/VG/LV /
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mkdir /boot
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mount /dev/sda1 /boot
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txz-in filesystem.tar.xz /
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write /etc/HOSTNAME "test01.example.com\n"
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upload /etc/resolv.conf /etc/resolv.conf</font>
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<b>EOF</b>
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<b>guestmount -a test1.img -i mnt/</b>
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<b>ls mnt</b>
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bin dev home lib mnt proc sbin tmp var
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boot etc initrd.img lost+found old-root root sys usr vmlinuz
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<b>cat mnt/etc/HOSTNAME</b>
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test01.example.com
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<b>fusermount -u mnt</b>
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</pre>
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<p class="sourcelnk"><a href="http://libguestfs.org/guestfish.1.html">manual for guestfish ...</a> <br/>
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<a href="http://libguestfs.org/guestmount.1.html">manual for guestmount ...</a></p>
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</td></tr>
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<tr><td valign="top" style="padding-bottom: 1.5em;">
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<pre>
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<b>virt-df -a /dev/vg/F15x32 -h</b>
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Filesystem Size Used Available Use%
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F15x32:/dev/sda1 484M 31M 428M 7%
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F15x32:/dev/vg_f15x32/lv_root 5.5G 3.4G 1.8G 63%
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</pre>
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<p class="sourcelnk"><a href="http://libguestfs.org/virt-df.1.html">manual ...</a></p>
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</td>
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<td valign="top" style="padding-bottom: 1.5em;">
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<pre>
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<b>virt-cat -c qemu:///system -d WinXP 'c:\boot.ini'</b>
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[boot loader]
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timeout=30
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default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
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[operating systems]
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multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=
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"Microsoft Windows XP Professional" /noexecute=optin
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/fastdetect
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</pre>
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<p class="sourcelnk"><a href="http://libguestfs.org/virt-cat.1.html">manual ...</a></p>
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</td></tr>
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<tr><td valign="top" style="padding-bottom: 1.5em;">
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<pre>
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<b>virt-edit -c qemu:///system -d F15x32 /etc/passwd</b>
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<i>(launches text editor to edit guest /etc/passwd)</i>
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<b>virt-edit -c qemu:///system -d F15x32 /etc/passwd \
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-e 's/^root:.*?:/root::/'</b>
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</pre>
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<p class="sourcelnk"><a href="http://libguestfs.org/virt-edit.1.html">manual ...</a></p>
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</td><td valign="top" style="padding-bottom: 1.5em;">
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<pre>
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<b>virt-win-reg -c qemu:///system --unsafe-printable-strings \
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Win7x32 'HKLM\SYSTEM\ControlSet001\Services\Tcpip\Parameters' \
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| grep DhcpIPAddress</b>
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"DhcpIPAddress"=str(1):"192.168.122.178"
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</pre>
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<p class="sourcelnk"><a href="http://libguestfs.org/virt-win-reg.1.html">manual ...</a></p>
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</td></tr>
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</table>
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<h2>Inspection</h2>
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<pre>
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$ <b>virt-filesystems -c qemu:///system -d Win7x32 --all --long -h --uuid</b>
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Name Type VFS Label MBR Size Parent UUID
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/dev/sda1 filesystem ntfs System Reserved - 100M - F81C92571C92112C
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/dev/sda2 filesystem ntfs - - 20G - F2E8996AE8992E3B
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/dev/sda1 partition - - 07 100M /dev/sda -
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/dev/sda2 partition - - 07 20G /dev/sda -
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/dev/sda device - - - 20G - -
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</pre>
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<p class="sourcelnk">
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<a href="http://libguestfs.org/virt-filesystems.1.html">manual ...</a>
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</p>
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<pre>
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$ <b>virt-inspector -c qemu:///system -d Win7x32</b>
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<font style="color: #888;"><?xml version="1.0"?></font>
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<font style="color: #888;"><operatingsystems></font>
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<font style="color: #888;"><operatingsystem></font>
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<font style="color: #888;"><root></font>/dev/sda2<font style="color: #888;"></root></font>
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<font style="color: #888;"><name></font>windows<font style="color: #888;"></name></font>
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<font style="color: #888;"><arch></font>i386<font style="color: #888;"></arch></font>
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<font style="color: #888;"><distro></font>windows<font style="color: #888;"></distro></font>
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<font style="color: #888;"><product_name></font>Windows 7 Enterprise<font style="color: #888;"></product_name></font>
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<font style="color: #888;"><product_variant></font>Client<font style="color: #888;"></product_variant></font>
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<font style="color: #888;"><major_version></font>6<font style="color: #888;"></major_version></font>
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<font style="color: #888;"><minor_version></font>1<font style="color: #888;"></minor_version></font>
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<font style="color: #888;"><windows_systemroot></font>/Windows<font style="color: #888;"></windows_systemroot></font>
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<font style="color: #888;"><windows_current_control_set></font>ControlSet001<font style="color: #888;"></windows_current_control_set></font>
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<font style="color: #888;"><hostname></font>win7x32<font style="color: #888;"></hostname></font>
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<i>... etc ...</i>
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</pre>
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<p class="sourcelnk">
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<a href="win7.xml">full XML ...</a> <br/>
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<a href="http://libguestfs.org/virt-inspector.1.html">manual ...</a>
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</p>
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<pre>
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char **roots;
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size_t i;
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char *type, *distro, *product_name;
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int major, minor;
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roots = <b>guestfs_inspect_os</b> (g);
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if (roots == NULL)
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exit (EXIT_FAILURE);
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if (roots[0] == NULL) {
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fprintf (stderr, "no operating systems found\n");
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exit (EXIT_FAILURE);
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}
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for (i = 0; roots[i] != NULL; ++i) {
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type = <b>guestfs_inspect_get_type</b> (g, roots[i]);
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distro = <b>guestfs_inspect_get_distro</b> (g, roots[i]);
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product_name = <b>guestfs_inspect_get_product_name</b> (g, roots[i]);
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major = <b>guestfs_inspect_get_major_version</b> (g, roots[i]);
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minor = <b>guestfs_inspect_get_minor_version</b> (g, roots[i]);
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printf ("Root: %s\n"
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" Type: %s\n"
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" Distro: %s\n"
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" Version: %d.%d\n"
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" Product name: %s\n\n");
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roots[i],
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type ? : "unknown", distro ? : "unknown", major, minor,
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product_name ? : "");
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free (type);
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free (distro);
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free (product_name);
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free (roots[i]);
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}
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free (roots);
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</pre>
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<p class="sourcelnk"><a href="http://git.annexia.org/?p=libguestfs.git;a=blob;f=rescue/virt-rescue.c;h=0c0036460434f1365d9591d6b2b805d999b07056;hb=HEAD#l351">full source ...</a></p>
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<table>
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<tr><td colspan="2" align="middle">
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<small><i>Click to enlarge the images</i></small>
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</td></tr>
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<tr><td width="50%">
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<a href="virt-manager.png"><img src="virt-manager-t.png"></a>
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</td><td width="50%" align="middle" valign="top">
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<a href="vmm-icons.png"><img src="vmm-icons-t.png"></a>
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</td></tr>
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</table>
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<h2>Graphical browsers</h2>
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<p>
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<img src="https://rwmj.files.wordpress.com/2011/07/guestfs-browser1.png?w=438&h=450"/>
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</p>
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<p>
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<img src="https://rwmj.files.wordpress.com/2011/07/guestfs-browser2.png?w=438&h=450"/>
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</p>
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<p>
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<img src="https://rwmj.files.wordpress.com/2011/07/guestfs-browser3.png?w=366&h=450"/>
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</p>
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<p>
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<img src="https://rwmj.files.wordpress.com/2011/07/guestfs-browser4.png?w=366&h=450"/>
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</p>
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<p class="sourcelnk"><a href="https://rwmj.wordpress.com/2011/07/29/some-screenshots-from-the-new-guest-filesystem-browser/">source ...</a></p>
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<p>
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<img src="https://rwmj.files.wordpress.com/2009/11/file-browser.png?w=500"/>
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</p>
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<p class="sourcelnk"><a href="https://rwmj.wordpress.com/2009/11/03/browsing-guests-using-fuse/">source ...</a></p>
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<h2>Find out more ...</h2>
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<p>
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<a href="http://libguestfs.org/">libguestfs.org</a> is the
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main website.
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</p>
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<p>
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<a href="http://libguestfs.org/guestfs.3.html">guestfs(3)</a>
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is the manual page documenting the C API and the internals.
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</p>
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<p>
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There are manual pages
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documenting <a href="http://libguestfs.org/guestfish.1.html">guestfish</a>, <a href="http://libguestfs.org/guestmount.1.html">guestmount</a>
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and each virt tool. See
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the <a href="http://libguestfs.org/">main website</a> or your
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local man command.
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</p>
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<p>
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For information about virt-v2v and virt-p2v, see
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<a href="http://libguestfs.org/virt-v2v/">http://libguestfs.org/virt-v2v/</a>
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</p>
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<hr/>
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<p style="font-size: 70%;">
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This page © 2011 Red Hat Inc. and distributed
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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</p>
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</body>
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</html>
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