1 # SOME DESCRIPTIVE TITLE.
2 # Copyright (C) YEAR Free Software Foundation, Inc.
3 # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
8 "Project-Id-Version: PACKAGE VERSION\n"
9 "Report-Msgid-Bugs-To: libguestfs@redhat.com\n"
10 "POT-Creation-Date: 2011-06-28 19:35+0200\n"
11 "PO-Revision-Date: 2010-09-02 14:46+0100\n"
12 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
13 "Language-Team: LANGUAGE <LL@li.org>\n"
16 "Content-Type: text/plain; charset=UTF-8\n"
17 "Content-Transfer-Encoding: 8bit\n"
21 #: ../src/guestfs.pod:3 ../fish/guestfish.pod:3
22 #: ../test-tool/libguestfs-test-tool.pod:3 ../fuse/guestmount.pod:3
23 #: ../tools/virt-win-reg.pl:35 ../tools/virt-list-filesystems.pl:30
24 #: ../tools/virt-tar.pl:31 ../tools/virt-make-fs.pl:35
25 #: ../tools/virt-list-partitions.pl:30
31 #: ../src/guestfs.pod:5
32 msgid "guestfs - Library for accessing and modifying virtual machine images"
37 #: ../src/guestfs.pod:7 ../fish/guestfish.pod:7
38 #: ../test-tool/libguestfs-test-tool.pod:7 ../fuse/guestmount.pod:7
39 #: ../tools/virt-win-reg.pl:39 ../tools/virt-list-filesystems.pl:34
40 #: ../tools/virt-tar.pl:35 ../tools/virt-make-fs.pl:39
41 #: ../tools/virt-list-partitions.pl:34
47 #: ../src/guestfs.pod:9
50 " #include <guestfs.h>\n"
56 #: ../src/guestfs.pod:11
59 " guestfs_h *g = guestfs_create ();\n"
60 " guestfs_add_drive (g, \"guest.img\");\n"
61 " guestfs_launch (g);\n"
62 " guestfs_mount (g, \"/dev/sda1\", \"/\");\n"
63 " guestfs_touch (g, \"/hello\");\n"
64 " guestfs_umount (g, \"/\");\n"
65 " guestfs_close (g);\n"
71 #: ../src/guestfs.pod:19
74 " cc prog.c -o prog -lguestfs\n"
76 " cc prog.c -o prog `pkg-config libguestfs --cflags --libs`\n"
82 #: ../src/guestfs.pod:23 ../fish/guestfish.pod:30
83 #: ../test-tool/libguestfs-test-tool.pod:11 ../fuse/guestmount.pod:20
84 #: ../tools/virt-win-reg.pl:63 ../tools/virt-list-filesystems.pl:40
85 #: ../tools/virt-tar.pl:77 ../tools/virt-make-fs.pl:47
86 #: ../tools/virt-list-partitions.pl:40
92 #: ../src/guestfs.pod:25
94 "Libguestfs is a library for accessing and modifying guest disk images. "
95 "Amongst the things this is good for: making batch configuration changes to "
96 "guests, getting disk used/free statistics (see also: virt-df), migrating "
97 "between virtualization systems (see also: virt-p2v), performing partial "
98 "backups, performing partial guest clones, cloning guests and changing "
99 "registry/UUID/hostname info, and much else besides."
104 #: ../src/guestfs.pod:33
106 "Libguestfs uses Linux kernel and qemu code, and can access any type of guest "
107 "filesystem that Linux and qemu can, including but not limited to: ext2/3/4, "
108 "btrfs, FAT and NTFS, LVM, many different disk partition schemes, qcow, "
114 #: ../src/guestfs.pod:38
116 "Libguestfs provides ways to enumerate guest storage (eg. partitions, LVs, "
117 "what filesystem is in each LV, etc.). It can also run commands in the "
118 "context of the guest. Also you can access filesystems over FUSE."
123 #: ../src/guestfs.pod:43
125 "Libguestfs is a library that can be linked with C and C++ management "
126 "programs (or management programs written in OCaml, Perl, Python, Ruby, Java, "
127 "PHP, Haskell or C#). You can also use it from shell scripts or the command "
133 #: ../src/guestfs.pod:48
135 "You don't need to be root to use libguestfs, although obviously you do need "
136 "enough permissions to access the disk images."
141 #: ../src/guestfs.pod:51
143 "Libguestfs is a large API because it can do many things. For a gentle "
144 "introduction, please read the L</API OVERVIEW> section next."
149 #: ../src/guestfs.pod:54
151 "There are also some example programs in the L<guestfs-examples(3)> manual "
157 #: ../src/guestfs.pod:57
163 #: ../src/guestfs.pod:59
165 "This section provides a gentler overview of the libguestfs API. We also try "
166 "to group API calls together, where that may not be obvious from reading "
167 "about the individual calls in the main section of this manual."
172 #: ../src/guestfs.pod:64
178 #: ../src/guestfs.pod:66
180 "Before you can use libguestfs calls, you have to create a handle. Then you "
181 "must add at least one disk image to the handle, followed by launching the "
182 "handle, then performing whatever operations you want, and finally closing "
183 "the handle. By convention we use the single letter C<g> for the name of the "
184 "handle variable, although of course you can use any name you want."
189 #: ../src/guestfs.pod:73
190 msgid "The general structure of all libguestfs-using programs looks like this:"
195 #: ../src/guestfs.pod:76
198 " guestfs_h *g = guestfs_create ();\n"
204 #: ../src/guestfs.pod:78
207 " /* Call guestfs_add_drive additional times if there are\n"
208 " * multiple disk images.\n"
210 " guestfs_add_drive (g, \"guest.img\");\n"
216 #: ../src/guestfs.pod:83
219 " /* Most manipulation calls won't work until you've launched\n"
220 " * the handle 'g'. You have to do this _after_ adding drives\n"
221 " * and _before_ other commands.\n"
223 " guestfs_launch (g);\n"
229 #: ../src/guestfs.pod:89
232 " /* Now you can examine what partitions, LVs etc are available.\n"
234 " char **partitions = guestfs_list_partitions (g);\n"
235 " char **logvols = guestfs_lvs (g);\n"
241 #: ../src/guestfs.pod:94
244 " /* To access a filesystem in the image, you must mount it.\n"
246 " guestfs_mount (g, \"/dev/sda1\", \"/\");\n"
251 #: ../src/guestfs.pod:98
254 " /* Now you can perform filesystem actions on the guest\n"
257 " guestfs_touch (g, \"/hello\");\n"
263 #: ../src/guestfs.pod:103
266 " /* This is only needed for libguestfs < 1.5.24. Since then\n"
267 " * it is done automatically when you close the handle. See\n"
268 " * discussion of autosync in this page.\n"
270 " guestfs_sync (g);\n"
276 #: ../src/guestfs.pod:109
279 " /* Close the handle 'g'. */\n"
280 " guestfs_close (g);\n"
286 #: ../src/guestfs.pod:112
288 "The code above doesn't include any error checking. In real code you should "
289 "check return values carefully for errors. In general all functions that "
290 "return integers return C<-1> on error, and all functions that return "
291 "pointers return C<NULL> on error. See section L</ERROR HANDLING> below for "
292 "how to handle errors, and consult the documentation for each function call "
293 "below to see precisely how they return error indications. See L<guestfs-"
294 "examples(3)> for fully worked examples."
299 #: ../src/guestfs.pod:121
305 #: ../src/guestfs.pod:123
307 "The image filename (C<\"guest.img\"> in the example above) could be a disk "
308 "image from a virtual machine, a L<dd(1)> copy of a physical hard disk, an "
309 "actual block device, or simply an empty file of zeroes that you have created "
310 "through L<posix_fallocate(3)>. Libguestfs lets you do useful things to all "
316 #: ../src/guestfs.pod:129
318 "The call you should use in modern code for adding drives is L</"
319 "guestfs_add_drive_opts>. To add a disk image, allowing writes, and "
320 "specifying that the format is raw, do:"
325 #: ../src/guestfs.pod:133
328 " guestfs_add_drive_opts (g, filename,\n"
329 " GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"raw\",\n"
336 #: ../src/guestfs.pod:137
337 msgid "You can add a disk read-only using:"
342 #: ../src/guestfs.pod:139
345 " guestfs_add_drive_opts (g, filename,\n"
346 " GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"raw\",\n"
347 " GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,\n"
354 #: ../src/guestfs.pod:144
356 "or by calling the older function L</guestfs_add_drive_ro>. In either case "
357 "libguestfs won't modify the file."
362 #: ../src/guestfs.pod:147
364 "Be extremely cautious if the disk image is in use, eg. if it is being used "
365 "by a virtual machine. Adding it read-write will almost certainly cause disk "
366 "corruption, but adding it read-only is safe."
371 #: ../src/guestfs.pod:151
373 "You must add at least one disk image, and you may add multiple disk images. "
374 "In the API, the disk images are usually referred to as C</dev/sda> (for the "
375 "first one you added), C</dev/sdb> (for the second one you added), etc."
380 #: ../src/guestfs.pod:156
382 "Once L</guestfs_launch> has been called you cannot add any more images. You "
383 "can call L</guestfs_list_devices> to get a list of the device names, in the "
384 "order that you added them. See also L</BLOCK DEVICE NAMING> below."
389 #: ../src/guestfs.pod:161
394 #: ../src/guestfs.pod:163
396 "Before you can read or write files, create directories and so on in a disk "
397 "image that contains filesystems, you have to mount those filesystems using "
398 "L</guestfs_mount_options> or L</guestfs_mount_ro>. If you already know that "
399 "a disk image contains (for example) one partition with a filesystem on that "
400 "partition, then you can mount it directly:"
404 #: ../src/guestfs.pod:170
407 " guestfs_mount_options (g, \"\", \"/dev/sda1\", \"/\");\n"
412 #: ../src/guestfs.pod:172
414 "where C</dev/sda1> means literally the first partition (C<1>) of the first "
415 "disk image that we added (C</dev/sda>). If the disk contains Linux LVM2 "
416 "logical volumes you could refer to those instead (eg. C</dev/VG/LV>). Note "
417 "that these are libguestfs virtual devices, and are nothing to do with host "
422 #: ../src/guestfs.pod:178
424 "If you are given a disk image and you don't know what it contains then you "
425 "have to find out. Libguestfs can do that too: use L</"
426 "guestfs_list_partitions> and L</guestfs_lvs> to list possible partitions and "
427 "LVs, and either try mounting each to see what is mountable, or else examine "
428 "them with L</guestfs_vfs_type> or L</guestfs_file>. To list just "
429 "filesystems, use L</guestfs_list_filesystems>."
433 #: ../src/guestfs.pod:186
435 "Libguestfs also has a set of APIs for inspection of unknown disk images (see "
436 "L</INSPECTION> below). But you might find it easier to look at higher level "
437 "programs built on top of libguestfs, in particular L<virt-inspector(1)>."
441 #: ../src/guestfs.pod:191
443 "To mount a filesystem read-only, use L</guestfs_mount_ro>. There are "
444 "several other variations of the C<guestfs_mount_*> call."
449 #: ../src/guestfs.pod:194
450 msgid "FILESYSTEM ACCESS AND MODIFICATION"
455 #: ../src/guestfs.pod:196
457 "The majority of the libguestfs API consists of fairly low-level calls for "
458 "accessing and modifying the files, directories, symlinks etc on mounted "
459 "filesystems. There are over a hundred such calls which you can find listed "
460 "in detail below in this man page, and we don't even pretend to cover them "
461 "all in this overview."
466 #: ../src/guestfs.pod:202
468 "Specify filenames as full paths, starting with C<\"/\"> and including the "
474 #: ../src/guestfs.pod:205
476 "For example, if you mounted a filesystem at C<\"/\"> and you want to read "
477 "the file called C<\"etc/passwd\"> then you could do:"
482 #: ../src/guestfs.pod:208
485 " char *data = guestfs_cat (g, \"/etc/passwd\");\n"
491 #: ../src/guestfs.pod:210
493 "This would return C<data> as a newly allocated buffer containing the full "
494 "content of that file (with some conditions: see also L</DOWNLOADING> below), "
495 "or C<NULL> if there was an error."
500 #: ../src/guestfs.pod:214
502 "As another example, to create a top-level directory on that filesystem "
503 "called C<\"var\"> you would do:"
508 #: ../src/guestfs.pod:217
511 " guestfs_mkdir (g, \"/var\");\n"
517 #: ../src/guestfs.pod:219
518 msgid "To create a symlink you could do:"
523 #: ../src/guestfs.pod:221
526 " guestfs_ln_s (g, \"/etc/init.d/portmap\",\n"
527 " \"/etc/rc3.d/S30portmap\");\n"
533 #: ../src/guestfs.pod:224
535 "Libguestfs will reject attempts to use relative paths and there is no "
536 "concept of a current working directory."
541 #: ../src/guestfs.pod:227
543 "Libguestfs can return errors in many situations: for example if the "
544 "filesystem isn't writable, or if a file or directory that you requested "
545 "doesn't exist. If you are using the C API (documented here) you have to "
546 "check for those error conditions after each call. (Other language bindings "
547 "turn these errors into exceptions)."
552 #: ../src/guestfs.pod:233
554 "File writes are affected by the per-handle umask, set by calling L</"
555 "guestfs_umask> and defaulting to 022. See L</UMASK>."
560 #: ../src/guestfs.pod:236
566 #: ../src/guestfs.pod:238
568 "Libguestfs contains API calls to read, create and modify partition tables on "
574 #: ../src/guestfs.pod:241
576 "In the common case where you want to create a single partition covering the "
577 "whole disk, you should use the L</guestfs_part_disk> call:"
582 #: ../src/guestfs.pod:245
585 " const char *parttype = \"mbr\";\n"
586 " if (disk_is_larger_than_2TB)\n"
587 " parttype = \"gpt\";\n"
588 " guestfs_part_disk (g, \"/dev/sda\", parttype);\n"
594 #: ../src/guestfs.pod:250
596 "Obviously this effectively wipes anything that was on that disk image before."
601 #: ../src/guestfs.pod:253
607 #: ../src/guestfs.pod:255
609 "Libguestfs provides access to a large part of the LVM2 API, such as L</"
610 "guestfs_lvcreate> and L</guestfs_vgremove>. It won't make much sense unless "
611 "you familiarize yourself with the concepts of physical volumes, volume "
612 "groups and logical volumes."
617 #: ../src/guestfs.pod:260
619 "This author strongly recommends reading the LVM HOWTO, online at L<http://"
620 "tldp.org/HOWTO/LVM-HOWTO/>."
625 #: ../src/guestfs.pod:263
630 #: ../src/guestfs.pod:265
632 "Use L</guestfs_cat> to download small, text only files. This call is "
633 "limited to files which are less than 2 MB and which cannot contain any ASCII "
634 "NUL (C<\\0>) characters. However the API is very simple to use."
639 #: ../src/guestfs.pod:269
641 "L</guestfs_read_file> can be used to read files which contain arbitrary 8 "
642 "bit data, since it returns a (pointer, size) pair. However it is still "
643 "limited to \"small\" files, less than 2 MB."
648 #: ../src/guestfs.pod:273
650 "L</guestfs_download> can be used to download any file, with no limits on "
651 "content or size (even files larger than 4 GB)."
656 #: ../src/guestfs.pod:276
658 "To download multiple files, see L</guestfs_tar_out> and L</guestfs_tgz_out>."
663 #: ../src/guestfs.pod:279
669 #: ../src/guestfs.pod:281
671 "It's often the case that you want to write a file or files to the disk image."
676 #: ../src/guestfs.pod:284
678 "To write a small file with fixed content, use L</guestfs_write>. To create "
679 "a file of all zeroes, use L</guestfs_truncate_size> (sparse) or L</"
680 "guestfs_fallocate64> (with all disk blocks allocated). There are a variety "
681 "of other functions for creating test files, for example L</guestfs_fill> and "
682 "L</guestfs_fill_pattern>."
687 #: ../src/guestfs.pod:290
689 "To upload a single file, use L</guestfs_upload>. This call has no limits on "
690 "file content or size (even files larger than 4 GB)."
695 #: ../src/guestfs.pod:293
697 "To upload multiple files, see L</guestfs_tar_in> and L</guestfs_tgz_in>."
702 #: ../src/guestfs.pod:295
704 "However the fastest way to upload I<large numbers of arbitrary files> is to "
705 "turn them into a squashfs or CD ISO (see L<mksquashfs(8)> and L<mkisofs(8)"
706 ">), then attach this using L</guestfs_add_drive_ro>. If you add the drive "
707 "in a predictable way (eg. adding it last after all other drives) then you "
708 "can get the device name from L</guestfs_list_devices> and mount it directly "
709 "using L</guestfs_mount_ro>. Note that squashfs images are sometimes non-"
710 "portable between kernel versions, and they don't support labels or UUIDs. "
711 "If you want to pre-build an image or you need to mount it using a label or "
712 "UUID, use an ISO image instead."
717 #: ../src/guestfs.pod:306
723 #: ../src/guestfs.pod:308
725 "There are various different commands for copying between files and devices "
726 "and in and out of the guest filesystem. These are summarised in the table "
732 #: ../src/guestfs.pod:314
733 msgid "B<file> to B<file>"
738 #: ../src/guestfs.pod:316
740 "Use L</guestfs_cp> to copy a single file, or L</guestfs_cp_a> to copy "
741 "directories recursively."
746 #: ../src/guestfs.pod:319
747 msgid "B<file or device> to B<file or device>"
752 #: ../src/guestfs.pod:321
754 "Use L</guestfs_dd> which efficiently uses L<dd(1)> to copy between files and "
755 "devices in the guest."
760 #: ../src/guestfs.pod:324
761 msgid "Example: duplicate the contents of an LV:"
766 #: ../src/guestfs.pod:326
769 " guestfs_dd (g, \"/dev/VG/Original\", \"/dev/VG/Copy\");\n"
775 #: ../src/guestfs.pod:328
777 "The destination (C</dev/VG/Copy>) must be at least as large as the source "
778 "(C</dev/VG/Original>). To copy less than the whole source device, use L</"
779 "guestfs_copy_size>."
784 #: ../src/guestfs.pod:332
785 msgid "B<file on the host> to B<file or device>"
790 #: ../src/guestfs.pod:334
791 msgid "Use L</guestfs_upload>. See L</UPLOADING> above."
796 #: ../src/guestfs.pod:336
797 msgid "B<file or device> to B<file on the host>"
802 #: ../src/guestfs.pod:338
803 msgid "Use L</guestfs_download>. See L</DOWNLOADING> above."
808 #: ../src/guestfs.pod:342
809 msgid "UPLOADING AND DOWNLOADING TO PIPES AND FILE DESCRIPTORS"
814 #: ../src/guestfs.pod:344
816 "Calls like L</guestfs_upload>, L</guestfs_download>, L</guestfs_tar_in>, L</"
817 "guestfs_tar_out> etc appear to only take filenames as arguments, so it "
818 "appears you can only upload and download to files. However many Un*x-like "
819 "hosts let you use the special device files C</dev/stdin>, C</dev/stdout>, C</"
820 "dev/stderr> and C</dev/fd/N> to read and write from stdin, stdout, stderr, "
821 "and arbitrary file descriptor N."
826 #: ../src/guestfs.pod:352
827 msgid "For example, L<virt-cat(1)> writes its output to stdout by doing:"
831 #: ../src/guestfs.pod:355
834 " guestfs_download (g, filename, \"/dev/stdout\");\n"
839 #: ../src/guestfs.pod:357
840 msgid "and you can write tar output to a file descriptor C<fd> by doing:"
844 #: ../src/guestfs.pod:359
848 " snprintf (devfd, sizeof devfd, \"/dev/fd/%d\", fd);\n"
849 " guestfs_tar_out (g, \"/\", devfd);\n"
855 #: ../src/guestfs.pod:363
856 msgid "LISTING FILES"
861 #: ../src/guestfs.pod:365
863 "L</guestfs_ll> is just designed for humans to read (mainly when using the "
864 "L<guestfish(1)>-equivalent command C<ll>)."
869 #: ../src/guestfs.pod:368
871 "L</guestfs_ls> is a quick way to get a list of files in a directory from "
872 "programs, as a flat list of strings."
877 #: ../src/guestfs.pod:371
879 "L</guestfs_readdir> is a programmatic way to get a list of files in a "
880 "directory, plus additional information about each one. It is more "
881 "equivalent to using the L<readdir(3)> call on a local filesystem."
886 #: ../src/guestfs.pod:375
888 "L</guestfs_find> and L</guestfs_find0> can be used to recursively list files."
893 #: ../src/guestfs.pod:378
894 msgid "RUNNING COMMANDS"
899 #: ../src/guestfs.pod:380
901 "Although libguestfs is primarily an API for manipulating files inside guest "
902 "images, we also provide some limited facilities for running commands inside "
908 #: ../src/guestfs.pod:384
909 msgid "There are many limitations to this:"
914 #: ../src/guestfs.pod:388 ../src/guestfs.pod:393 ../src/guestfs.pod:398
915 #: ../src/guestfs.pod:402 ../src/guestfs.pod:407 ../src/guestfs.pod:411
916 #: ../src/guestfs.pod:416 ../src/guestfs.pod:421 ../src/guestfs.pod:1064
917 #: ../src/guestfs.pod:1068 ../src/guestfs.pod:1072 ../src/guestfs.pod:1077
918 #: ../src/guestfs.pod:1085 ../src/guestfs.pod:1104 ../src/guestfs.pod:1112
919 #: ../src/guestfs.pod:1134 ../src/guestfs.pod:1138 ../src/guestfs.pod:1142
920 #: ../src/guestfs.pod:1146 ../src/guestfs.pod:1150 ../src/guestfs.pod:1154
921 #: ../src/guestfs.pod:1643 ../src/guestfs.pod:1648 ../src/guestfs.pod:1652
922 #: ../src/guestfs.pod:1754 ../src/guestfs.pod:1759 ../src/guestfs.pod:1763
923 #: ../src/guestfs.pod:1773 ../src/guestfs.pod:2008 ../src/guestfs.pod:2013
924 #: ../src/guestfs.pod:2019 ../src/guestfs.pod:2027 ../src/guestfs.pod:2381
925 #: ../src/guestfs.pod:2387 ../src/guestfs.pod:2392 ../src/guestfs.pod:2398
926 #: ../src/guestfs.pod:2967 ../src/guestfs.pod:2971 ../src/guestfs.pod:2975
927 #: ../src/guestfs.pod:2979 ../src/guestfs-actions.pod:15
928 #: ../src/guestfs-actions.pod:22 ../src/guestfs-actions.pod:583
929 #: ../src/guestfs-actions.pod:591 ../src/guestfs-actions.pod:598
930 #: ../src/guestfs-actions.pod:605 ../src/guestfs-actions.pod:1603
931 #: ../src/guestfs-actions.pod:1607 ../src/guestfs-actions.pod:1611
932 #: ../src/guestfs-actions.pod:1615 ../src/guestfs-actions.pod:1623
933 #: ../src/guestfs-actions.pod:1627 ../src/guestfs-actions.pod:1631
934 #: ../src/guestfs-actions.pod:1641 ../src/guestfs-actions.pod:1645
935 #: ../src/guestfs-actions.pod:1649 ../src/guestfs-actions.pod:1787
936 #: ../src/guestfs-actions.pod:1791 ../src/guestfs-actions.pod:1796
937 #: ../src/guestfs-actions.pod:1801 ../src/guestfs-actions.pod:1862
938 #: ../src/guestfs-actions.pod:1866 ../src/guestfs-actions.pod:1871
939 #: ../src/guestfs-actions.pod:2783 ../src/guestfs-actions.pod:2789
940 #: ../src/guestfs-actions.pod:2797 ../src/guestfs-actions.pod:2804
941 #: ../src/guestfs-actions.pod:2811 ../fish/guestfish.pod:445
942 #: ../fish/guestfish.pod:449 ../fish/guestfish.pod:453
943 #: ../fish/guestfish.pod:457 ../fish/guestfish-actions.pod:13
944 #: ../fish/guestfish-actions.pod:20 ../fish/guestfish-actions.pod:385
945 #: ../fish/guestfish-actions.pod:393 ../fish/guestfish-actions.pod:400
946 #: ../fish/guestfish-actions.pod:407 ../fish/guestfish-actions.pod:1074
947 #: ../fish/guestfish-actions.pod:1078 ../fish/guestfish-actions.pod:1082
948 #: ../fish/guestfish-actions.pod:1086 ../fish/guestfish-actions.pod:1094
949 #: ../fish/guestfish-actions.pod:1098 ../fish/guestfish-actions.pod:1102
950 #: ../fish/guestfish-actions.pod:1112 ../fish/guestfish-actions.pod:1116
951 #: ../fish/guestfish-actions.pod:1120 ../fish/guestfish-actions.pod:1210
952 #: ../fish/guestfish-actions.pod:1214 ../fish/guestfish-actions.pod:1219
953 #: ../fish/guestfish-actions.pod:1224 ../fish/guestfish-actions.pod:1266
954 #: ../fish/guestfish-actions.pod:1270 ../fish/guestfish-actions.pod:1275
955 #: ../fish/guestfish-actions.pod:1902 ../fish/guestfish-actions.pod:1908
956 #: ../fish/guestfish-actions.pod:1916 ../fish/guestfish-actions.pod:1923
957 #: ../fish/guestfish-actions.pod:1930 ../tools/virt-win-reg.pl:195
958 #: ../tools/virt-win-reg.pl:200 ../tools/virt-win-reg.pl:206
959 #: ../tools/virt-win-reg.pl:708 ../tools/virt-win-reg.pl:714
960 #: ../tools/virt-win-reg.pl:720
966 #: ../src/guestfs.pod:390
968 "The kernel version that the command runs under will be different from what "
974 #: ../src/guestfs.pod:395
976 "If the command needs to communicate with daemons, then most likely they "
982 #: ../src/guestfs.pod:400
983 msgid "The command will be running in limited memory."
988 #: ../src/guestfs.pod:404
990 "The network may not be available unless you enable it (see L</"
991 "guestfs_set_network>)."
996 #: ../src/guestfs.pod:409
997 msgid "Only supports Linux guests (not Windows, BSD, etc)."
1002 #: ../src/guestfs.pod:413
1004 "Architecture limitations (eg. won't work for a PPC guest on an X86 host)."
1009 #: ../src/guestfs.pod:418
1011 "For SELinux guests, you may need to enable SELinux and load policy first. "
1012 "See L</SELINUX> in this manpage."
1017 #: ../src/guestfs.pod:423
1019 "I<Security:> It is not safe to run commands from untrusted, possibly "
1020 "malicious guests. These commands may attempt to exploit your program by "
1021 "sending unexpected output. They could also try to exploit the Linux kernel "
1022 "or qemu provided by the libguestfs appliance. They could use the network "
1023 "provided by the libguestfs appliance to bypass ordinary network partitions "
1024 "and firewalls. They could use the elevated privileges or different SELinux "
1025 "context of your program to their advantage."
1030 #: ../src/guestfs.pod:432
1032 "A secure alternative is to use libguestfs to install a \"firstboot\" script "
1033 "(a script which runs when the guest next boots normally), and to have this "
1034 "script run the commands you want in the normal context of the running guest, "
1035 "network security and so on. For information about other security issues, "
1041 #: ../src/guestfs.pod:440
1043 "The two main API calls to run commands are L</guestfs_command> and L</"
1044 "guestfs_sh> (there are also variations)."
1049 #: ../src/guestfs.pod:443
1051 "The difference is that L</guestfs_sh> runs commands using the shell, so any "
1052 "shell globs, redirections, etc will work."
1057 #: ../src/guestfs.pod:446
1058 msgid "CONFIGURATION FILES"
1063 #: ../src/guestfs.pod:448
1065 "To read and write configuration files in Linux guest filesystems, we "
1066 "strongly recommend using Augeas. For example, Augeas understands how to "
1067 "read and write, say, a Linux shadow password file or X.org configuration "
1068 "file, and so avoids you having to write that code."
1073 #: ../src/guestfs.pod:453
1075 "The main Augeas calls are bound through the C<guestfs_aug_*> APIs. We don't "
1076 "document Augeas itself here because there is excellent documentation on the "
1077 "L<http://augeas.net/> website."
1082 #: ../src/guestfs.pod:457
1084 "If you don't want to use Augeas (you fool!) then try calling L</"
1085 "guestfs_read_lines> to get the file as a list of lines which you can iterate "
1091 #: ../src/guestfs.pod:461
1097 #: ../src/guestfs.pod:463
1099 "We support SELinux guests. To ensure that labeling happens correctly in "
1100 "SELinux guests, you need to enable SELinux and load the guest's policy:"
1105 #: ../src/guestfs.pod:469 ../src/guestfs.pod:1257 ../src/guestfs.pod:1395
1106 #: ../src/guestfs.pod:2426
1112 #: ../src/guestfs.pod:471
1113 msgid "Before launching, do:"
1118 #: ../src/guestfs.pod:473
1121 " guestfs_set_selinux (g, 1);\n"
1127 #: ../src/guestfs.pod:475 ../src/guestfs.pod:1261 ../src/guestfs.pod:1399
1128 #: ../src/guestfs.pod:2451
1134 #: ../src/guestfs.pod:477
1136 "After mounting the guest's filesystem(s), load the policy. This is best "
1137 "done by running the L<load_policy(8)> command in the guest itself:"
1142 #: ../src/guestfs.pod:481
1145 " guestfs_sh (g, \"/usr/sbin/load_policy\");\n"
1151 #: ../src/guestfs.pod:483
1153 "(Older versions of C<load_policy> require you to specify the name of the "
1159 #: ../src/guestfs.pod:486 ../src/guestfs.pod:1405
1165 #: ../src/guestfs.pod:488
1167 "Optionally, set the security context for the API. The correct security "
1168 "context to use can only be known by inspecting the guest. As an example:"
1173 #: ../src/guestfs.pod:492
1176 " guestfs_setcon (g, \"unconfined_u:unconfined_r:unconfined_t:s0\");\n"
1182 #: ../src/guestfs.pod:496
1183 msgid "This will work for running commands and editing existing files."
1188 #: ../src/guestfs.pod:498
1190 "When new files are created, you may need to label them explicitly, for "
1191 "example by running the external command C<restorecon pathname>."
1196 #: ../src/guestfs.pod:502
1202 #: ../src/guestfs.pod:504
1204 "Certain calls are affected by the current file mode creation mask (the "
1205 "\"umask\"). In particular ones which create files or directories, such as "
1206 "L</guestfs_touch>, L</guestfs_mknod> or L</guestfs_mkdir>. This affects "
1207 "either the default mode that the file is created with or modifies the mode "
1213 #: ../src/guestfs.pod:510
1215 "The default umask is C<022>, so files are created with modes such as C<0644> "
1216 "and directories with C<0755>."
1221 #: ../src/guestfs.pod:513
1223 "There are two ways to avoid being affected by umask. Either set umask to 0 "
1224 "(call C<guestfs_umask (g, 0)> early after launching). Or call L</"
1225 "guestfs_chmod> after creating each file or directory."
1230 #: ../src/guestfs.pod:517
1231 msgid "For more information about umask, see L<umask(2)>."
1236 #: ../src/guestfs.pod:519 ../fish/guestfish.pod:767
1237 msgid "ENCRYPTED DISKS"
1242 #: ../src/guestfs.pod:521
1244 "Libguestfs allows you to access Linux guests which have been encrypted using "
1245 "whole disk encryption that conforms to the Linux Unified Key Setup (LUKS) "
1246 "standard. This includes nearly all whole disk encryption systems used by "
1247 "modern Linux guests."
1252 #: ../src/guestfs.pod:527
1254 "Use L</guestfs_vfs_type> to identify LUKS-encrypted block devices (it "
1255 "returns the string C<crypto_LUKS>)."
1260 #: ../src/guestfs.pod:530
1262 "Then open these devices by calling L</guestfs_luks_open>. Obviously you "
1263 "will require the passphrase!"
1268 #: ../src/guestfs.pod:533
1270 "Opening a LUKS device creates a new device mapper device called C</dev/"
1271 "mapper/mapname> (where C<mapname> is the string you supply to L</"
1272 "guestfs_luks_open>). Reads and writes to this mapper device are decrypted "
1273 "from and encrypted to the underlying block device respectively."
1278 #: ../src/guestfs.pod:539
1280 "LVM volume groups on the device can be made visible by calling L</"
1281 "guestfs_vgscan> followed by L</guestfs_vg_activate_all>. The logical volume"
1282 "(s) can now be mounted in the usual way."
1287 #: ../src/guestfs.pod:543
1289 "Use the reverse process to close a LUKS device. Unmount any logical volumes "
1290 "on it, deactivate the volume groups by caling C<guestfs_vg_activate (g, 0, "
1291 "[\"/dev/VG\"])>. Then close the mapper device by calling L</"
1292 "guestfs_luks_close> on the C</dev/mapper/mapname> device (I<not> the "
1293 "underlying encrypted block device)."
1298 #: ../src/guestfs.pod:550
1303 #: ../src/guestfs.pod:552
1305 "Libguestfs has APIs for inspecting an unknown disk image to find out if it "
1306 "contains operating systems, an install CD or a live CD. (These APIs used to "
1307 "be in a separate Perl-only library called L<Sys::Guestfs::Lib(3)> but since "
1308 "version 1.5.3 the most frequently used part of this library has been "
1309 "rewritten in C and moved into the core code)."
1314 #: ../src/guestfs.pod:559
1316 "Add all disks belonging to the unknown virtual machine and call L</"
1317 "guestfs_launch> in the usual way."
1322 #: ../src/guestfs.pod:562
1324 "Then call L</guestfs_inspect_os>. This function uses other libguestfs calls "
1325 "and certain heuristics, and returns a list of operating systems that were "
1326 "found. An empty list means none were found. A single element is the root "
1327 "filesystem of the operating system. For dual- or multi-boot guests, "
1328 "multiple roots can be returned, each one corresponding to a separate "
1329 "operating system. (Multi-boot virtual machines are extremely rare in the "
1330 "world of virtualization, but since this scenario can happen, we have built "
1331 "libguestfs to deal with it.)"
1336 #: ../src/guestfs.pod:571
1338 "For each root, you can then call various C<guestfs_inspect_get_*> functions "
1339 "to get additional details about that operating system. For example, call L</"
1340 "guestfs_inspect_get_type> to return the string C<windows> or C<linux> for "
1341 "Windows and Linux-based operating systems respectively."
1346 #: ../src/guestfs.pod:577
1348 "Un*x-like and Linux-based operating systems usually consist of several "
1349 "filesystems which are mounted at boot time (for example, a separate boot "
1350 "partition mounted on C</boot>). The inspection rules are able to detect how "
1351 "filesystems correspond to mount points. Call "
1352 "C<guestfs_inspect_get_mountpoints> to get this mapping. It might return a "
1353 "hash table like this example:"
1358 #: ../src/guestfs.pod:584
1361 " /boot => /dev/sda1\n"
1362 " / => /dev/vg_guest/lv_root\n"
1363 " /usr => /dev/vg_guest/lv_usr\n"
1369 #: ../src/guestfs.pod:588
1371 "The caller can then make calls to L</guestfs_mount_options> to mount the "
1372 "filesystems as suggested."
1377 #: ../src/guestfs.pod:591
1379 "Be careful to mount filesystems in the right order (eg. C</> before C</"
1380 "usr>). Sorting the keys of the hash by length, shortest first, should work."
1385 #: ../src/guestfs.pod:595
1387 "Inspection currently only works for some common operating systems. "
1388 "Contributors are welcome to send patches for other operating systems that we "
1389 "currently cannot detect."
1394 #: ../src/guestfs.pod:599
1396 "Encrypted disks must be opened before inspection. See L</ENCRYPTED DISKS> "
1397 "for more details. The L</guestfs_inspect_os> function just ignores any "
1398 "encrypted devices."
1403 #: ../src/guestfs.pod:603
1405 "A note on the implementation: The call L</guestfs_inspect_os> performs "
1406 "inspection and caches the results in the guest handle. Subsequent calls to "
1407 "C<guestfs_inspect_get_*> return this cached information, but I<do not> re-"
1408 "read the disks. If you change the content of the guest disks, you can redo "
1409 "inspection by calling L</guestfs_inspect_os> again. (L</"
1410 "guestfs_inspect_list_applications> works a little differently from the other "
1411 "calls and does read the disks. See documentation for that function for "
1416 #: ../src/guestfs.pod:612
1417 msgid "INSPECTING INSTALL DISKS"
1421 #: ../src/guestfs.pod:614
1423 "Libguestfs (since 1.9.4) can detect some install disks, install CDs, live "
1428 #: ../src/guestfs.pod:617
1430 "Call L</guestfs_inspect_get_format> to return the format of the operating "
1431 "system, which currently can be C<installed> (a regular operating system) or "
1432 "C<installer> (some sort of install disk)."
1436 #: ../src/guestfs.pod:621
1438 "Further information is available about the operating system that can be "
1439 "installed using the regular inspection APIs like L</"
1440 "guestfs_inspect_get_product_name>, L</guestfs_inspect_get_major_version> etc."
1444 #: ../src/guestfs.pod:626
1446 "Some additional information specific to installer disks is also available "
1447 "from the L</guestfs_inspect_is_live>, L</guestfs_inspect_is_netinst> and L</"
1448 "guestfs_inspect_is_multipart> calls."
1453 #: ../src/guestfs.pod:631
1454 msgid "SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS"
1459 #: ../src/guestfs.pod:633
1461 "Libguestfs can mount NTFS partitions. It does this using the L<http://www."
1462 "ntfs-3g.org/> driver."
1467 #: ../src/guestfs.pod:636
1468 msgid "DRIVE LETTERS AND PATHS"
1473 #: ../src/guestfs.pod:638
1475 "DOS and Windows still use drive letters, and the filesystems are always "
1476 "treated as case insensitive by Windows itself, and therefore you might find "
1477 "a Windows configuration file referring to a path like C<c:\\windows"
1478 "\\system32>. When the filesystem is mounted in libguestfs, that directory "
1479 "might be referred to as C</WINDOWS/System32>."
1483 #: ../src/guestfs.pod:644
1485 "Drive letter mappings can be found using inspection (see L</INSPECTION> and "
1486 "L</guestfs_inspect_get_drive_mappings>)"
1490 #: ../src/guestfs.pod:647
1492 "Dealing with separator characters (backslash vs forward slash) is outside "
1493 "the scope of libguestfs, but usually a simple character replacement will "
1498 #: ../src/guestfs.pod:651
1500 "To resolve the case insensitivity of paths, call L</"
1501 "guestfs_case_sensitive_path>."
1506 #: ../src/guestfs.pod:654
1507 msgid "ACCESSING THE WINDOWS REGISTRY"
1512 #: ../src/guestfs.pod:656
1514 "Libguestfs also provides some help for decoding Windows Registry \"hive\" "
1515 "files, through the library C<hivex> which is part of the libguestfs project "
1516 "although ships as a separate tarball. You have to locate and download the "
1517 "hive file(s) yourself, and then pass them to C<hivex> functions. See also "
1518 "the programs L<hivexml(1)>, L<hivexsh(1)>, L<hivexregedit(1)> and L<virt-win-"
1519 "reg(1)> for more help on this issue."
1524 #: ../src/guestfs.pod:664
1525 msgid "SYMLINKS ON NTFS-3G FILESYSTEMS"
1530 #: ../src/guestfs.pod:666
1532 "Ntfs-3g tries to rewrite \"Junction Points\" and NTFS \"symbolic links\" to "
1533 "provide something which looks like a Linux symlink. The way it tries to do "
1534 "the rewriting is described here:"
1539 #: ../src/guestfs.pod:670
1541 "L<http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-"
1547 #: ../src/guestfs.pod:672
1549 "The essential problem is that ntfs-3g simply does not have enough "
1550 "information to do a correct job. NTFS links can contain drive letters and "
1551 "references to external device GUIDs that ntfs-3g has no way of resolving. "
1552 "It is almost certainly the case that libguestfs callers should ignore what "
1553 "ntfs-3g does (ie. don't use L</guestfs_readlink> on NTFS volumes)."
1558 #: ../src/guestfs.pod:679
1560 "Instead if you encounter a symbolic link on an ntfs-3g filesystem, use L</"
1561 "guestfs_lgetxattr> to read the C<system.ntfs_reparse_data> extended "
1562 "attribute, and read the raw reparse data from that (you can find the format "
1563 "documented in various places around the web)."
1568 #: ../src/guestfs.pod:684
1569 msgid "EXTENDED ATTRIBUTES ON NTFS-3G FILESYSTEMS"
1574 #: ../src/guestfs.pod:686
1576 "There are other useful extended attributes that can be read from ntfs-3g "
1577 "filesystems (using L</guestfs_getxattr>). See:"
1582 #: ../src/guestfs.pod:689
1584 "L<http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/>"
1589 #: ../src/guestfs.pod:691
1590 msgid "USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES"
1595 #: ../src/guestfs.pod:693
1597 "Although we don't want to discourage you from using the C API, we will "
1598 "mention here that the same API is also available in other languages."
1602 #: ../src/guestfs.pod:696
1604 "The API is broadly identical in all supported languages. This means that "
1605 "the C call C<guestfs_add_drive_ro(g,file)> is C<$g-E<gt>add_drive_ro($file)> "
1606 "in Perl, C<g.add_drive_ro(file)> in Python, and C<g#add_drive_ro file> in "
1607 "OCaml. In other words, a straightforward, predictable isomorphism between "
1613 #: ../src/guestfs.pod:702
1615 "Error messages are automatically transformed into exceptions if the language "
1621 #: ../src/guestfs.pod:705
1623 "We don't try to \"object orientify\" parts of the API in OO languages, "
1624 "although contributors are welcome to write higher level APIs above what we "
1625 "provide in their favourite languages if they wish."
1630 #: ../src/guestfs.pod:711
1636 #: ../src/guestfs.pod:713
1638 "You can use the I<guestfs.h> header file from C++ programs. The C++ API is "
1639 "identical to the C API. C++ classes and exceptions are not used."
1644 #: ../src/guestfs.pod:717
1650 #: ../src/guestfs.pod:719
1652 "The C# bindings are highly experimental. Please read the warnings at the "
1653 "top of C<csharp/Libguestfs.cs>."
1658 #: ../src/guestfs.pod:722
1664 #: ../src/guestfs.pod:724
1666 "This is the only language binding that is working but incomplete. Only "
1667 "calls which return simple integers have been bound in Haskell, and we are "
1668 "looking for help to complete this binding."
1673 #: ../src/guestfs.pod:728
1679 #: ../src/guestfs.pod:730
1681 "Full documentation is contained in the Javadoc which is distributed with "
1687 #: ../src/guestfs.pod:733
1692 #: ../src/guestfs.pod:735
1693 msgid "See L<guestfs-ocaml(3)>."
1698 #: ../src/guestfs.pod:737
1703 #: ../src/guestfs.pod:739
1704 msgid "See L<guestfs-perl(3)> and L<Sys::Guestfs(3)>."
1709 #: ../src/guestfs.pod:741
1715 #: ../src/guestfs.pod:743
1717 "For documentation see C<README-PHP> supplied with libguestfs sources or in "
1718 "the php-libguestfs package for your distribution."
1723 #: ../src/guestfs.pod:746
1724 msgid "The PHP binding only works correctly on 64 bit machines."
1729 #: ../src/guestfs.pod:748
1734 #: ../src/guestfs.pod:750
1735 msgid "See L<guestfs-python(3)>."
1740 #: ../src/guestfs.pod:752
1745 #: ../src/guestfs.pod:754
1746 msgid "See L<guestfs-ruby(3)>."
1751 #: ../src/guestfs.pod:756
1752 msgid "B<shell scripts>"
1756 #: ../src/guestfs.pod:758
1757 msgid "See L<guestfish(1)>."
1762 #: ../src/guestfs.pod:762
1763 msgid "LIBGUESTFS GOTCHAS"
1768 #: ../src/guestfs.pod:764
1770 "L<http://en.wikipedia.org/wiki/Gotcha_(programming)>: \"A feature of a "
1771 "system [...] that works in the way it is documented but is counterintuitive "
1772 "and almost invites mistakes.\""
1777 #: ../src/guestfs.pod:768
1779 "Since we developed libguestfs and the associated tools, there are several "
1780 "things we would have designed differently, but are now stuck with for "
1781 "backwards compatibility or other reasons. If there is ever a libguestfs 2.0 "
1782 "release, you can expect these to change. Beware of them."
1787 #: ../src/guestfs.pod:776
1788 msgid "Autosync / forgetting to sync."
1792 #: ../src/guestfs.pod:778
1794 "I<Update:> Autosync is enabled by default for all API users starting from "
1795 "libguestfs 1.5.24. This section only applies to older versions."
1800 #: ../src/guestfs.pod:781
1802 "When modifying a filesystem from C or another language, you B<must> unmount "
1803 "all filesystems and call L</guestfs_sync> explicitly before you close the "
1804 "libguestfs handle. You can also call:"
1809 #: ../src/guestfs.pod:785
1812 " guestfs_set_autosync (g, 1);\n"
1818 #: ../src/guestfs.pod:787
1820 "to have the unmount/sync done automatically for you when the handle 'g' is "
1821 "closed. (This feature is called \"autosync\", L</guestfs_set_autosync> q.v.)"
1826 #: ../src/guestfs.pod:791
1828 "If you forget to do this, then it is entirely possible that your changes "
1829 "won't be written out, or will be partially written, or (very rarely) that "
1830 "you'll get disk corruption."
1835 #: ../src/guestfs.pod:795
1837 "Note that in L<guestfish(3)> autosync is the default. So quick and dirty "
1838 "guestfish scripts that forget to sync will work just fine, which can make "
1839 "this very puzzling if you are trying to debug a problem."
1844 #: ../src/guestfs.pod:799
1845 msgid "Mount option C<-o sync> should not be the default."
1850 #: ../src/guestfs.pod:801
1852 "If you use L</guestfs_mount>, then C<-o sync,noatime> are added implicitly. "
1853 "However C<-o sync> does not add any reliability benefit, but does have a "
1854 "very large performance impact."
1859 #: ../src/guestfs.pod:805
1861 "The work around is to use L</guestfs_mount_options> and set the mount "
1862 "options that you actually want to use."
1867 #: ../src/guestfs.pod:808
1868 msgid "Read-only should be the default."
1873 #: ../src/guestfs.pod:810
1875 "In L<guestfish(3)>, I<--ro> should be the default, and you should have to "
1876 "specify I<--rw> if you want to make changes to the image."
1881 #: ../src/guestfs.pod:813
1882 msgid "This would reduce the potential to corrupt live VM images."
1887 #: ../src/guestfs.pod:815
1889 "Note that many filesystems change the disk when you just mount and unmount, "
1890 "even if you didn't perform any writes. You need to use L</"
1891 "guestfs_add_drive_ro> to guarantee that the disk is not changed."
1896 #: ../src/guestfs.pod:819
1897 msgid "guestfish command line is hard to use."
1902 #: ../src/guestfs.pod:821
1904 "C<guestfish disk.img> doesn't do what people expect (open C<disk.img> for "
1905 "examination). It tries to run a guestfish command C<disk.img> which doesn't "
1906 "exist, so it fails. In earlier versions of guestfish the error message was "
1907 "also unintuitive, but we have corrected this since. Like the Bourne shell, "
1908 "we should have used C<guestfish -c command> to run commands."
1913 #: ../src/guestfs.pod:828
1914 msgid "guestfish megabyte modifiers don't work right on all commands"
1919 #: ../src/guestfs.pod:830
1921 "In recent guestfish you can use C<1M> to mean 1 megabyte (and similarly for "
1922 "other modifiers). What guestfish actually does is to multiply the number "
1923 "part by the modifier part and pass the result to the C API. However this "
1924 "doesn't work for a few APIs which aren't expecting bytes, but are already "
1925 "expecting some other unit (eg. megabytes)."
1930 #: ../src/guestfs.pod:837
1931 msgid "The most common is L</guestfs_lvcreate>. The guestfish command:"
1936 #: ../src/guestfs.pod:839
1939 " lvcreate LV VG 100M\n"
1945 #: ../src/guestfs.pod:841
1947 "does not do what you might expect. Instead because L</guestfs_lvcreate> is "
1948 "already expecting megabytes, this tries to create a 100 I<terabyte> (100 "
1949 "megabytes * megabytes) logical volume. The error message you get from this "
1950 "is also a little obscure."
1955 #: ../src/guestfs.pod:846
1957 "This could be fixed in the generator by specially marking parameters and "
1958 "return values which take bytes or other units."
1963 #: ../src/guestfs.pod:849
1964 msgid "Ambiguity between devices and paths"
1969 #: ../src/guestfs.pod:851
1971 "There is a subtle ambiguity in the API between a device name (eg. C</dev/"
1972 "sdb2>) and a similar pathname. A file might just happen to be called "
1973 "C<sdb2> in the directory C</dev> (consider some non-Unix VM image)."
1978 #: ../src/guestfs.pod:856
1980 "In the current API we usually resolve this ambiguity by having two separate "
1981 "calls, for example L</guestfs_checksum> and L</guestfs_checksum_device>. "
1982 "Some API calls are ambiguous and (incorrectly) resolve the problem by "
1983 "detecting if the path supplied begins with C</dev/>."
1988 #: ../src/guestfs.pod:862
1990 "To avoid both the ambiguity and the need to duplicate some calls, we could "
1991 "make paths/devices into structured names. One way to do this would be to "
1992 "use a notation like grub (C<hd(0,0)>), although nobody really likes this "
1993 "aspect of grub. Another way would be to use a structured type, equivalent "
1994 "to this OCaml type:"
1999 #: ../src/guestfs.pod:868
2002 " type path = Path of string | Device of int | Partition of int * int\n"
2008 #: ../src/guestfs.pod:870
2009 msgid "which would allow you to pass arguments like:"
2014 #: ../src/guestfs.pod:872
2017 " Path \"/foo/bar\"\n"
2018 " Device 1 (* /dev/sdb, or perhaps /dev/sda *)\n"
2019 " Partition (1, 2) (* /dev/sdb2 (or is it /dev/sda2 or /dev/sdb3?) *)\n"
2020 " Path \"/dev/sdb2\" (* not a device *)\n"
2026 #: ../src/guestfs.pod:877
2028 "As you can see there are still problems to resolve even with this "
2029 "representation. Also consider how it might work in guestfish."
2034 #: ../src/guestfs.pod:882
2035 msgid "KEYS AND PASSPHRASES"
2040 #: ../src/guestfs.pod:884
2042 "Certain libguestfs calls take a parameter that contains sensitive key "
2043 "material, passed in as a C string."
2048 #: ../src/guestfs.pod:887
2050 "In the future we would hope to change the libguestfs implementation so that "
2051 "keys are L<mlock(2)>-ed into physical RAM, and thus can never end up in "
2052 "swap. However this is I<not> done at the moment, because of the complexity "
2053 "of such an implementation."
2058 #: ../src/guestfs.pod:892
2060 "Therefore you should be aware that any key parameter you pass to libguestfs "
2061 "might end up being written out to the swap partition. If this is a concern, "
2062 "scrub the swap partition or don't use libguestfs on encrypted devices."
2067 #: ../src/guestfs.pod:897
2068 msgid "MULTIPLE HANDLES AND MULTIPLE THREADS"
2073 #: ../src/guestfs.pod:899
2075 "All high-level libguestfs actions are synchronous. If you want to use "
2076 "libguestfs asynchronously then you must create a thread."
2081 #: ../src/guestfs.pod:902
2083 "Only use the handle from a single thread. Either use the handle exclusively "
2084 "from one thread, or provide your own mutex so that two threads cannot issue "
2085 "calls on the same handle at the same time."
2090 #: ../src/guestfs.pod:906
2092 "See the graphical program guestfs-browser for one possible architecture for "
2093 "multithreaded programs using libvirt and libguestfs."
2098 #: ../src/guestfs.pod:909
2103 #: ../src/guestfs.pod:911
2105 "Libguestfs needs a supermin appliance, which it finds by looking along an "
2111 #: ../src/guestfs.pod:914
2113 "By default it looks for these in the directory C<$libdir/guestfs> (eg. C</"
2114 "usr/local/lib/guestfs> or C</usr/lib64/guestfs>)."
2119 #: ../src/guestfs.pod:917
2121 "Use L</guestfs_set_path> or set the environment variable L</LIBGUESTFS_PATH> "
2122 "to change the directories that libguestfs will search in. The value is a "
2123 "colon-separated list of paths. The current directory is I<not> searched "
2124 "unless the path contains an empty element or C<.>. For example "
2125 "C<LIBGUESTFS_PATH=:/usr/lib/guestfs> would search the current directory and "
2126 "then C</usr/lib/guestfs>."
2131 #: ../src/guestfs.pod:924
2132 msgid "QEMU WRAPPERS"
2137 #: ../src/guestfs.pod:926
2139 "If you want to compile your own qemu, run qemu from a non-standard location, "
2140 "or pass extra arguments to qemu, then you can write a shell-script wrapper "
2146 #: ../src/guestfs.pod:930
2148 "There is one important rule to remember: you I<must C<exec qemu>> as the "
2149 "last command in the shell script (so that qemu replaces the shell and "
2150 "becomes the direct child of the libguestfs-using program). If you don't do "
2151 "this, then the qemu process won't be cleaned up correctly."
2156 #: ../src/guestfs.pod:935
2158 "Here is an example of a wrapper, where I have built my own copy of qemu from "
2164 #: ../src/guestfs.pod:938
2168 " qemudir=/home/rjones/d/qemu\n"
2169 " exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios \"$@\"\n"
2175 #: ../src/guestfs.pod:942
2177 "Save this script as C</tmp/qemu.wrapper> (or wherever), C<chmod +x>, and "
2178 "then use it by setting the LIBGUESTFS_QEMU environment variable. For "
2184 #: ../src/guestfs.pod:946
2187 " LIBGUESTFS_QEMU=/tmp/qemu.wrapper guestfish\n"
2193 #: ../src/guestfs.pod:948
2195 "Note that libguestfs also calls qemu with the -help and -version options in "
2196 "order to determine features."
2200 #: ../src/guestfs.pod:951
2201 msgid "ATTACHING TO RUNNING DAEMONS"
2205 #: ../src/guestfs.pod:953
2207 "I<Note (1):> This is B<highly experimental> and has a tendency to eat "
2208 "babies. Use with caution."
2212 #: ../src/guestfs.pod:956
2214 "I<Note (2):> This section explains how to attach to a running daemon from a "
2215 "low level perspective. For most users, simply using virt tools such as "
2216 "L<guestfish(1)> with the I<--live> option will \"just work\"."
2220 #: ../src/guestfs.pod:960
2221 msgid "Using guestfs_set_attach_method"
2225 #: ../src/guestfs.pod:962
2227 "By calling L</guestfs_set_attach_method> you can change how the library "
2228 "connects to the C<guestfsd> daemon in L</guestfs_launch> (read L</"
2229 "ARCHITECTURE> for some background)."
2233 #: ../src/guestfs.pod:966
2235 "The normal attach method is C<appliance>, where a small appliance is created "
2236 "containing the daemon, and then the library connects to this."
2240 #: ../src/guestfs.pod:969
2242 "Setting attach method to C<unix:I<path>> (where I<path> is the path of a "
2243 "Unix domain socket) causes L</guestfs_launch> to connect to an existing "
2244 "daemon over the Unix domain socket."
2248 #: ../src/guestfs.pod:973
2250 "The normal use for this is to connect to a running virtual machine that "
2251 "contains a C<guestfsd> daemon, and send commands so you can read and write "
2252 "files inside the live virtual machine."
2256 #: ../src/guestfs.pod:977
2257 msgid "Using guestfs_add_domain with live flag"
2261 #: ../src/guestfs.pod:979
2263 "L</guestfs_add_domain> provides some help for getting the correct attach "
2264 "method. If you pass the C<live> option to this function, then (if the "
2265 "virtual machine is running) it will examine the libvirt XML looking for a "
2266 "virtio-serial channel to connect to:"
2270 #: ../src/guestfs.pod:985
2277 " <channel type='unix'>\n"
2278 " <source mode='bind' path='/path/to/socket'/>\n"
2279 " <target type='virtio' name='org.libguestfs.channel.0'/>\n"
2288 #: ../src/guestfs.pod:997
2290 "L</guestfs_add_domain> extracts C</path/to/socket> and sets the attach "
2291 "method to C<unix:/path/to/socket>."
2295 #: ../src/guestfs.pod:1000
2297 "Some of the libguestfs tools (including guestfish) support a I<--live> "
2298 "option which is passed through to L</guestfs_add_domain> thus allowing you "
2299 "to attach to and modify live virtual machines."
2303 #: ../src/guestfs.pod:1004
2305 "The virtual machine needs to have been set up beforehand so that it has the "
2306 "virtio-serial channel and so that guestfsd is running inside it."
2311 #: ../src/guestfs.pod:1008
2312 msgid "ABI GUARANTEE"
2317 #: ../src/guestfs.pod:1010
2319 "We guarantee the libguestfs ABI (binary interface), for public, high-level "
2320 "actions as outlined in this section. Although we will deprecate some "
2321 "actions, for example if they get replaced by newer calls, we will keep the "
2322 "old actions forever. This allows you the developer to program in confidence "
2323 "against the libguestfs API."
2328 #: ../src/guestfs.pod:1016
2329 msgid "BLOCK DEVICE NAMING"
2334 #: ../src/guestfs.pod:1018
2336 "In the kernel there is now quite a profusion of schemata for naming block "
2337 "devices (in this context, by I<block device> I mean a physical or virtual "
2338 "hard drive). The original Linux IDE driver used names starting with C</dev/"
2339 "hd*>. SCSI devices have historically used a different naming scheme, C</dev/"
2340 "sd*>. When the Linux kernel I<libata> driver became a popular replacement "
2341 "for the old IDE driver (particularly for SATA devices) those devices also "
2342 "used the C</dev/sd*> scheme. Additionally we now have virtual machines with "
2343 "paravirtualized drivers. This has created several different naming systems, "
2344 "such as C</dev/vd*> for virtio disks and C</dev/xvd*> for Xen PV disks."
2349 #: ../src/guestfs.pod:1030
2351 "As discussed above, libguestfs uses a qemu appliance running an embedded "
2352 "Linux kernel to access block devices. We can run a variety of appliances "
2353 "based on a variety of Linux kernels."
2358 #: ../src/guestfs.pod:1034
2360 "This causes a problem for libguestfs because many API calls use device or "
2361 "partition names. Working scripts and the recipe (example) scripts that we "
2362 "make available over the internet could fail if the naming scheme changes."
2367 #: ../src/guestfs.pod:1039
2369 "Therefore libguestfs defines C</dev/sd*> as the I<standard naming scheme>. "
2370 "Internally C</dev/sd*> names are translated, if necessary, to other names as "
2371 "required. For example, under RHEL 5 which uses the C</dev/hd*> scheme, any "
2372 "device parameter C</dev/sda2> is translated to C</dev/hda2> transparently."
2377 #: ../src/guestfs.pod:1045
2379 "Note that this I<only> applies to parameters. The L</guestfs_list_devices>, "
2380 "L</guestfs_list_partitions> and similar calls return the true names of the "
2381 "devices and partitions as known to the appliance."
2386 #: ../src/guestfs.pod:1050
2387 msgid "ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION"
2392 #: ../src/guestfs.pod:1052
2394 "Usually this translation is transparent. However in some (very rare) cases "
2395 "you may need to know the exact algorithm. Such cases include where you use "
2396 "L</guestfs_config> to add a mixture of virtio and IDE devices to the qemu-"
2397 "based appliance, so have a mixture of C</dev/sd*> and C</dev/vd*> devices."
2402 #: ../src/guestfs.pod:1058
2404 "The algorithm is applied only to I<parameters> which are known to be either "
2405 "device or partition names. Return values from functions such as L</"
2406 "guestfs_list_devices> are never changed."
2411 #: ../src/guestfs.pod:1066
2412 msgid "Is the string a parameter which is a device or partition name?"
2417 #: ../src/guestfs.pod:1070
2418 msgid "Does the string begin with C</dev/sd>?"
2423 #: ../src/guestfs.pod:1074
2425 "Does the named device exist? If so, we use that device. However if I<not> "
2426 "then we continue with this algorithm."
2431 #: ../src/guestfs.pod:1079
2432 msgid "Replace initial C</dev/sd> string with C</dev/hd>."
2437 #: ../src/guestfs.pod:1081
2438 msgid "For example, change C</dev/sda2> to C</dev/hda2>."
2443 #: ../src/guestfs.pod:1083
2444 msgid "If that named device exists, use it. If not, continue."
2449 #: ../src/guestfs.pod:1087
2450 msgid "Replace initial C</dev/sd> string with C</dev/vd>."
2455 #: ../src/guestfs.pod:1089
2456 msgid "If that named device exists, use it. If not, return an error."
2461 #: ../src/guestfs.pod:1093
2462 msgid "PORTABILITY CONCERNS WITH BLOCK DEVICE NAMING"
2467 #: ../src/guestfs.pod:1095
2469 "Although the standard naming scheme and automatic translation is useful for "
2470 "simple programs and guestfish scripts, for larger programs it is best not to "
2471 "rely on this mechanism."
2476 #: ../src/guestfs.pod:1099
2478 "Where possible for maximum future portability programs using libguestfs "
2479 "should use these future-proof techniques:"
2484 #: ../src/guestfs.pod:1106
2486 "Use L</guestfs_list_devices> or L</guestfs_list_partitions> to list actual "
2487 "device names, and then use those names directly."
2492 #: ../src/guestfs.pod:1109
2494 "Since those device names exist by definition, they will never be translated."
2499 #: ../src/guestfs.pod:1114
2501 "Use higher level ways to identify filesystems, such as LVM names, UUIDs and "
2502 "filesystem labels."
2507 #: ../src/guestfs.pod:1119
2513 #: ../src/guestfs.pod:1121
2515 "This section discusses security implications of using libguestfs, "
2516 "particularly with untrusted or malicious guests or disk images."
2521 #: ../src/guestfs.pod:1124
2522 msgid "GENERAL SECURITY CONSIDERATIONS"
2527 #: ../src/guestfs.pod:1126
2529 "Be careful with any files or data that you download from a guest (by "
2530 "\"download\" we mean not just the L</guestfs_download> command but any "
2531 "command that reads files, filenames, directories or anything else from a "
2532 "disk image). An attacker could manipulate the data to fool your program "
2533 "into doing the wrong thing. Consider cases such as:"
2538 #: ../src/guestfs.pod:1136
2539 msgid "the data (file etc) not being present"
2544 #: ../src/guestfs.pod:1140
2545 msgid "being present but empty"
2550 #: ../src/guestfs.pod:1144
2551 msgid "being much larger than normal"
2556 #: ../src/guestfs.pod:1148
2557 msgid "containing arbitrary 8 bit data"
2562 #: ../src/guestfs.pod:1152
2563 msgid "being in an unexpected character encoding"
2568 #: ../src/guestfs.pod:1156
2569 msgid "containing homoglyphs."
2574 #: ../src/guestfs.pod:1160
2575 msgid "SECURITY OF MOUNTING FILESYSTEMS"
2580 #: ../src/guestfs.pod:1162
2582 "When you mount a filesystem under Linux, mistakes in the kernel filesystem "
2583 "(VFS) module can sometimes be escalated into exploits by deliberately "
2584 "creating a malicious, malformed filesystem. These exploits are very severe "
2585 "for two reasons. Firstly there are very many filesystem drivers in the "
2586 "kernel, and many of them are infrequently used and not much developer "
2587 "attention has been paid to the code. Linux userspace helps potential "
2588 "crackers by detecting the filesystem type and automatically choosing the "
2589 "right VFS driver, even if that filesystem type is obscure or unexpected for "
2590 "the administrator. Secondly, a kernel-level exploit is like a local root "
2591 "exploit (worse in some ways), giving immediate and total access to the "
2592 "system right down to the hardware level."
2597 #: ../src/guestfs.pod:1175
2599 "That explains why you should never mount a filesystem from an untrusted "
2600 "guest on your host kernel. How about libguestfs? We run a Linux kernel "
2601 "inside a qemu virtual machine, usually running as a non-root user. The "
2602 "attacker would need to write a filesystem which first exploited the kernel, "
2603 "and then exploited either qemu virtualization (eg. a faulty qemu driver) or "
2604 "the libguestfs protocol, and finally to be as serious as the host kernel "
2605 "exploit it would need to escalate its privileges to root. This multi-step "
2606 "escalation, performed by a static piece of data, is thought to be extremely "
2607 "hard to do, although we never say 'never' about security issues."
2612 #: ../src/guestfs.pod:1186
2614 "In any case callers can reduce the attack surface by forcing the filesystem "
2615 "type when mounting (use L</guestfs_mount_vfs>)."
2620 #: ../src/guestfs.pod:1189
2621 msgid "PROTOCOL SECURITY"
2626 #: ../src/guestfs.pod:1191
2628 "The protocol is designed to be secure, being based on RFC 4506 (XDR) with a "
2629 "defined upper message size. However a program that uses libguestfs must "
2630 "also take care - for example you can write a program that downloads a binary "
2631 "from a disk image and executes it locally, and no amount of protocol "
2632 "security will save you from the consequences."
2637 #: ../src/guestfs.pod:1197
2638 msgid "INSPECTION SECURITY"
2643 #: ../src/guestfs.pod:1199
2645 "Parts of the inspection API (see L</INSPECTION>) return untrusted strings "
2646 "directly from the guest, and these could contain any 8 bit data. Callers "
2647 "should be careful to escape these before printing them to a structured file "
2648 "(for example, use HTML escaping if creating a web page)."
2653 #: ../src/guestfs.pod:1205
2655 "Guest configuration may be altered in unusual ways by the administrator of "
2656 "the virtual machine, and may not reflect reality (particularly for untrusted "
2657 "or actively malicious guests). For example we parse the hostname from "
2658 "configuration files like C</etc/sysconfig/network> that we find in the "
2659 "guest, but the guest administrator can easily manipulate these files to "
2660 "provide the wrong hostname."
2665 #: ../src/guestfs.pod:1213
2667 "The inspection API parses guest configuration using two external libraries: "
2668 "Augeas (Linux configuration) and hivex (Windows Registry). Both are "
2669 "designed to be robust in the face of malicious data, although denial of "
2670 "service attacks are still possible, for example with oversized configuration "
2676 #: ../src/guestfs.pod:1219
2677 msgid "RUNNING UNTRUSTED GUEST COMMANDS"
2682 #: ../src/guestfs.pod:1221
2684 "Be very cautious about running commands from the guest. By running a "
2685 "command in the guest, you are giving CPU time to a binary that you do not "
2686 "control, under the same user account as the library, albeit wrapped in qemu "
2687 "virtualization. More information and alternatives can be found in the "
2688 "section L</RUNNING COMMANDS>."
2693 #: ../src/guestfs.pod:1227
2694 msgid "CVE-2010-3851"
2699 #: ../src/guestfs.pod:1229
2700 msgid "https://bugzilla.redhat.com/642934"
2705 #: ../src/guestfs.pod:1231
2707 "This security bug concerns the automatic disk format detection that qemu "
2708 "does on disk images."
2713 #: ../src/guestfs.pod:1234
2715 "A raw disk image is just the raw bytes, there is no header. Other disk "
2716 "images like qcow2 contain a special header. Qemu deals with this by looking "
2717 "for one of the known headers, and if none is found then assuming the disk "
2718 "image must be raw."
2723 #: ../src/guestfs.pod:1239
2725 "This allows a guest which has been given a raw disk image to write some "
2726 "other header. At next boot (or when the disk image is accessed by "
2727 "libguestfs) qemu would do autodetection and think the disk image format was, "
2728 "say, qcow2 based on the header written by the guest."
2733 #: ../src/guestfs.pod:1244
2735 "This in itself would not be a problem, but qcow2 offers many features, one "
2736 "of which is to allow a disk image to refer to another image (called the "
2737 "\"backing disk\"). It does this by placing the path to the backing disk "
2738 "into the qcow2 header. This path is not validated and could point to any "
2739 "host file (eg. \"/etc/passwd\"). The backing disk is then exposed through "
2740 "\"holes\" in the qcow2 disk image, which of course is completely under the "
2741 "control of the attacker."
2746 #: ../src/guestfs.pod:1252
2748 "In libguestfs this is rather hard to exploit except under two circumstances:"
2753 #: ../src/guestfs.pod:1259
2754 msgid "You have enabled the network or have opened the disk in write mode."
2759 #: ../src/guestfs.pod:1263
2761 "You are also running untrusted code from the guest (see L</RUNNING "
2767 #: ../src/guestfs.pod:1268
2769 "The way to avoid this is to specify the expected disk format when adding "
2770 "disks (the optional C<format> option to L</guestfs_add_drive_opts>). You "
2771 "should always do this if the disk is raw format, and it's a good idea for "
2777 #: ../src/guestfs.pod:1273
2779 "For disks added from libvirt using calls like L</guestfs_add_domain>, the "
2780 "format is fetched from libvirt and passed through."
2785 #: ../src/guestfs.pod:1276
2787 "For libguestfs tools, use the I<--format> command line parameter as "
2793 #: ../src/guestfs.pod:1279
2794 msgid "CONNECTION MANAGEMENT"
2799 #: ../src/guestfs.pod:1281
2805 #: ../src/guestfs.pod:1283
2807 "C<guestfs_h> is the opaque type representing a connection handle. Create a "
2808 "handle by calling L</guestfs_create>. Call L</guestfs_close> to free the "
2809 "handle and release all resources used."
2813 #: ../src/guestfs.pod:1287
2815 "For information on using multiple handles and threads, see the section L</"
2816 "MULTIPLE HANDLES AND MULTIPLE THREADS> above."
2821 #: ../src/guestfs.pod:1290
2822 msgid "guestfs_create"
2827 #: ../src/guestfs.pod:1292
2830 " guestfs_h *guestfs_create (void);\n"
2836 #: ../src/guestfs.pod:1294
2837 msgid "Create a connection handle."
2841 #: ../src/guestfs.pod:1296
2843 "On success this returns a non-NULL pointer to a handle. On error it returns "
2848 #: ../src/guestfs.pod:1299
2850 "You have to \"configure\" the handle after creating it. This includes "
2851 "calling L</guestfs_add_drive_opts> (or one of the equivalent calls) on the "
2852 "handle at least once."
2857 #: ../src/guestfs.pod:1303
2858 msgid "After configuring the handle, you have to call L</guestfs_launch>."
2862 #: ../src/guestfs.pod:1305
2864 "You may also want to configure error handling for the handle. See the L</"
2865 "ERROR HANDLING> section below."
2870 #: ../src/guestfs.pod:1308
2871 msgid "guestfs_close"
2876 #: ../src/guestfs.pod:1310
2879 " void guestfs_close (guestfs_h *g);\n"
2885 #: ../src/guestfs.pod:1312
2886 msgid "This closes the connection handle and frees up all resources used."
2890 #: ../src/guestfs.pod:1314
2892 "If autosync was set on the handle and the handle was launched, then this "
2893 "implicitly calls various functions to unmount filesystems and sync the "
2894 "disk. See L</guestfs_set_autosync> for more details."
2898 #: ../src/guestfs.pod:1318
2899 msgid "If a close callback was set on the handle, then it is called."
2904 #: ../src/guestfs.pod:1320
2905 msgid "ERROR HANDLING"
2910 #: ../src/guestfs.pod:1322
2912 "API functions can return errors. For example, almost all functions that "
2913 "return C<int> will return C<-1> to indicate an error."
2918 #: ../src/guestfs.pod:1325
2920 "Additional information is available for errors: an error message string and "
2921 "optionally an error number (errno) if the thing that failed was a system "
2927 #: ../src/guestfs.pod:1329
2929 "You can get at the additional information about the last error on the handle "
2930 "by calling L</guestfs_last_error>, L</guestfs_last_errno>, and/or by setting "
2931 "up an error handler with L</guestfs_set_error_handler>."
2936 #: ../src/guestfs.pod:1334
2938 "When the handle is created, a default error handler is installed which "
2939 "prints the error message string to C<stderr>. For small short-running "
2940 "command line programs it is sufficient to do:"
2945 #: ../src/guestfs.pod:1338
2948 " if (guestfs_launch (g) == -1)\n"
2949 " exit (EXIT_FAILURE);\n"
2955 #: ../src/guestfs.pod:1341
2957 "since the default error handler will ensure that an error message has been "
2958 "printed to C<stderr> before the program exits."
2963 #: ../src/guestfs.pod:1344
2965 "For other programs the caller will almost certainly want to install an "
2966 "alternate error handler or do error handling in-line like this:"
2971 #: ../src/guestfs.pod:1347
2974 " g = guestfs_create ();\n"
2980 #: ../src/guestfs.pod:1349
2983 " /* This disables the default behaviour of printing errors\n"
2985 " guestfs_set_error_handler (g, NULL, NULL);\n"
2991 #: ../src/guestfs.pod:1353
2994 " if (guestfs_launch (g) == -1) {\n"
2995 " /* Examine the error message and print it etc. */\n"
2996 " char *msg = guestfs_last_error (g);\n"
2997 " int errnum = guestfs_last_errno (g);\n"
2998 " fprintf (stderr, \"%s\\n\", msg);\n"
3006 #: ../src/guestfs.pod:1361
3008 "Out of memory errors are handled differently. The default action is to call "
3009 "L<abort(3)>. If this is undesirable, then you can set a handler using L</"
3010 "guestfs_set_out_of_memory_handler>."
3015 #: ../src/guestfs.pod:1365
3017 "L</guestfs_create> returns C<NULL> if the handle cannot be created, and "
3018 "because there is no handle if this happens there is no way to get additional "
3019 "error information. However L</guestfs_create> is supposed to be a "
3020 "lightweight operation which can only fail because of insufficient memory (it "
3021 "returns NULL in this case)."
3026 #: ../src/guestfs.pod:1371
3027 msgid "guestfs_last_error"
3032 #: ../src/guestfs.pod:1373
3035 " const char *guestfs_last_error (guestfs_h *g);\n"
3041 #: ../src/guestfs.pod:1375
3043 "This returns the last error message that happened on C<g>. If there has not "
3044 "been an error since the handle was created, then this returns C<NULL>."
3049 #: ../src/guestfs.pod:1379
3051 "The lifetime of the returned string is until the next error occurs, or L</"
3052 "guestfs_close> is called."
3057 #: ../src/guestfs.pod:1382
3058 msgid "guestfs_last_errno"
3063 #: ../src/guestfs.pod:1384
3066 " int guestfs_last_errno (guestfs_h *g);\n"
3072 #: ../src/guestfs.pod:1386
3073 msgid "This returns the last error number (errno) that happened on C<g>."
3078 #: ../src/guestfs.pod:1388
3079 msgid "If successful, an errno integer not equal to zero is returned."
3084 #: ../src/guestfs.pod:1390
3086 "If no error, this returns 0. This call can return 0 in three situations:"
3091 #: ../src/guestfs.pod:1397
3092 msgid "There has not been any error on the handle."
3097 #: ../src/guestfs.pod:1401
3099 "There has been an error but the errno was meaningless. This corresponds to "
3100 "the case where the error did not come from a failed system call, but for "
3101 "some other reason."
3106 #: ../src/guestfs.pod:1407
3108 "There was an error from a failed system call, but for some reason the errno "
3109 "was not captured and returned. This usually indicates a bug in libguestfs."
3114 #: ../src/guestfs.pod:1413
3116 "Libguestfs tries to convert the errno from inside the applicance into a "
3117 "corresponding errno for the caller (not entirely trivial: the appliance "
3118 "might be running a completely different operating system from the library "
3119 "and error numbers are not standardized across Un*xen). If this could not be "
3120 "done, then the error is translated to C<EINVAL>. In practice this should "
3121 "only happen in very rare circumstances."
3126 #: ../src/guestfs.pod:1421
3127 msgid "guestfs_set_error_handler"
3132 #: ../src/guestfs.pod:1423
3135 " typedef void (*guestfs_error_handler_cb) (guestfs_h *g,\n"
3137 " const char *msg);\n"
3138 " void guestfs_set_error_handler (guestfs_h *g,\n"
3139 " guestfs_error_handler_cb cb,\n"
3146 #: ../src/guestfs.pod:1430
3148 "The callback C<cb> will be called if there is an error. The parameters "
3149 "passed to the callback are an opaque data pointer and the error message "
3155 #: ../src/guestfs.pod:1434
3157 "C<errno> is not passed to the callback. To get that the callback must call "
3158 "L</guestfs_last_errno>."
3163 #: ../src/guestfs.pod:1437
3165 "Note that the message string C<msg> is freed as soon as the callback "
3166 "function returns, so if you want to stash it somewhere you must make your "
3172 #: ../src/guestfs.pod:1441
3173 msgid "The default handler prints messages on C<stderr>."
3178 #: ../src/guestfs.pod:1443
3179 msgid "If you set C<cb> to C<NULL> then I<no> handler is called."
3184 #: ../src/guestfs.pod:1445
3185 msgid "guestfs_get_error_handler"
3190 #: ../src/guestfs.pod:1447
3193 " guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *g,\n"
3194 " void **opaque_rtn);\n"
3200 #: ../src/guestfs.pod:1450
3201 msgid "Returns the current error handler callback."
3206 #: ../src/guestfs.pod:1452
3207 msgid "guestfs_set_out_of_memory_handler"
3212 #: ../src/guestfs.pod:1454
3215 " typedef void (*guestfs_abort_cb) (void);\n"
3216 " int guestfs_set_out_of_memory_handler (guestfs_h *g,\n"
3217 " guestfs_abort_cb);\n"
3223 #: ../src/guestfs.pod:1458
3225 "The callback C<cb> will be called if there is an out of memory situation. "
3226 "I<Note this callback must not return>."
3231 #: ../src/guestfs.pod:1461
3232 msgid "The default is to call L<abort(3)>."
3237 #: ../src/guestfs.pod:1463
3239 "You cannot set C<cb> to C<NULL>. You can't ignore out of memory situations."
3244 #: ../src/guestfs.pod:1466
3245 msgid "guestfs_get_out_of_memory_handler"
3250 #: ../src/guestfs.pod:1468
3253 " guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *g);\n"
3259 #: ../src/guestfs.pod:1470
3260 msgid "This returns the current out of memory handler."
3265 #: ../src/guestfs.pod:1472
3271 #: ../src/guestfs.pod:1474 ../fish/guestfish.pod:1010
3277 #: ../src/guestfs.pod:1476
3283 #: ../src/guestfs.pod:1478
3289 #: ../src/guestfs.pod:1480
3290 msgid "AVAILABILITY"
3295 #: ../src/guestfs.pod:1482
3296 msgid "GROUPS OF FUNCTIONALITY IN THE APPLIANCE"
3301 #: ../src/guestfs.pod:1484
3303 "Using L</guestfs_available> you can test availability of the following "
3304 "groups of functions. This test queries the appliance to see if the "
3305 "appliance you are currently using supports the functionality."
3310 #: ../src/guestfs.pod:1489
3311 msgid "@AVAILABILITY@"
3316 #: ../src/guestfs.pod:1491
3317 msgid "GUESTFISH supported COMMAND"
3322 #: ../src/guestfs.pod:1493
3324 "In L<guestfish(3)> there is a handy interactive command C<supported> which "
3325 "prints out the available groups and whether they are supported by this build "
3326 "of libguestfs. Note however that you have to do C<run> first."
3331 #: ../src/guestfs.pod:1498
3332 msgid "SINGLE CALLS AT COMPILE TIME"
3337 #: ../src/guestfs.pod:1500
3339 "Since version 1.5.8, C<E<lt>guestfs.hE<gt>> defines symbols for each C API "
3340 "function, such as:"
3345 #: ../src/guestfs.pod:1503
3348 " #define LIBGUESTFS_HAVE_DD 1\n"
3354 #: ../src/guestfs.pod:1505
3355 msgid "if L</guestfs_dd> is available."
3360 #: ../src/guestfs.pod:1507
3362 "Before version 1.5.8, if you needed to test whether a single libguestfs "
3363 "function is available at compile time, we recommended using build tools such "
3364 "as autoconf or cmake. For example in autotools you could use:"
3369 #: ../src/guestfs.pod:1512
3372 " AC_CHECK_LIB([guestfs],[guestfs_create])\n"
3373 " AC_CHECK_FUNCS([guestfs_dd])\n"
3379 #: ../src/guestfs.pod:1515
3381 "which would result in C<HAVE_GUESTFS_DD> being either defined or not defined "
3387 #: ../src/guestfs.pod:1518
3388 msgid "SINGLE CALLS AT RUN TIME"
3393 #: ../src/guestfs.pod:1520
3395 "Testing at compile time doesn't guarantee that a function really exists in "
3396 "the library. The reason is that you might be dynamically linked against a "
3397 "previous I<libguestfs.so> (dynamic library) which doesn't have the call. "
3398 "This situation unfortunately results in a segmentation fault, which is a "
3399 "shortcoming of the C dynamic linking system itself."
3404 #: ../src/guestfs.pod:1527
3406 "You can use L<dlopen(3)> to test if a function is available at run time, as "
3407 "in this example program (note that you still need the compile time check as "
3413 #: ../src/guestfs.pod:1531
3416 " #include <stdio.h>\n"
3417 " #include <stdlib.h>\n"
3418 " #include <unistd.h>\n"
3419 " #include <dlfcn.h>\n"
3420 " #include <guestfs.h>\n"
3426 #: ../src/guestfs.pod:1537
3431 " #ifdef LIBGUESTFS_HAVE_DD\n"
3433 " int has_function;\n"
3439 #: ../src/guestfs.pod:1543
3442 " /* Test if the function guestfs_dd is really available. */\n"
3443 " dl = dlopen (NULL, RTLD_LAZY);\n"
3445 " fprintf (stderr, \"dlopen: %s\\n\", dlerror ());\n"
3446 " exit (EXIT_FAILURE);\n"
3448 " has_function = dlsym (dl, \"guestfs_dd\") != NULL;\n"
3455 #: ../src/guestfs.pod:1552
3458 " if (!has_function)\n"
3459 " printf (\"this libguestfs.so does NOT have guestfs_dd function\\n\");\n"
3461 " printf (\"this libguestfs.so has guestfs_dd function\\n\");\n"
3462 " /* Now it's safe to call\n"
3463 " guestfs_dd (g, \"foo\", \"bar\");\n"
3467 " printf (\"guestfs_dd function was not found at compile time\\n\");\n"
3475 #: ../src/guestfs.pod:1565
3477 "You may think the above is an awful lot of hassle, and it is. There are "
3478 "other ways outside of the C linking system to ensure that this kind of "
3479 "incompatibility never arises, such as using package versioning:"
3484 #: ../src/guestfs.pod:1570
3487 " Requires: libguestfs >= 1.0.80\n"
3493 #: ../src/guestfs.pod:1572
3494 msgid "CALLS WITH OPTIONAL ARGUMENTS"
3499 #: ../src/guestfs.pod:1574
3501 "A recent feature of the API is the introduction of calls which take optional "
3502 "arguments. In C these are declared 3 ways. The main way is as a call which "
3503 "takes variable arguments (ie. C<...>), as in this example:"
3508 #: ../src/guestfs.pod:1579
3511 " int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...);\n"
3517 #: ../src/guestfs.pod:1581
3519 "Call this with a list of optional arguments, terminated by C<-1>. So to "
3520 "call with no optional arguments specified:"
3525 #: ../src/guestfs.pod:1584
3528 " guestfs_add_drive_opts (g, filename, -1);\n"
3534 #: ../src/guestfs.pod:1586
3535 msgid "With a single optional argument:"
3540 #: ../src/guestfs.pod:1588
3543 " guestfs_add_drive_opts (g, filename,\n"
3544 " GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"qcow2\",\n"
3551 #: ../src/guestfs.pod:1592
3557 #: ../src/guestfs.pod:1594
3560 " guestfs_add_drive_opts (g, filename,\n"
3561 " GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"qcow2\",\n"
3562 " GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,\n"
3569 #: ../src/guestfs.pod:1599
3571 "and so forth. Don't forget the terminating C<-1> otherwise Bad Things will "
3577 #: ../src/guestfs.pod:1602
3578 msgid "USING va_list FOR OPTIONAL ARGUMENTS"
3583 #: ../src/guestfs.pod:1604
3585 "The second variant has the same name with the suffix C<_va>, which works the "
3586 "same way but takes a C<va_list>. See the C manual for details. For the "
3587 "example function, this is declared:"
3592 #: ../src/guestfs.pod:1608
3595 " int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename,\n"
3602 #: ../src/guestfs.pod:1611
3603 msgid "CONSTRUCTING OPTIONAL ARGUMENTS"
3608 #: ../src/guestfs.pod:1613
3610 "The third variant is useful where you need to construct these calls. You "
3611 "pass in a structure where you fill in the optional fields. The structure "
3612 "has a bitmask as the first element which you must set to indicate which "
3613 "fields you have filled in. For our example function the structure and call "
3619 #: ../src/guestfs.pod:1619
3622 " struct guestfs_add_drive_opts_argv {\n"
3623 " uint64_t bitmask;\n"
3625 " const char *format;\n"
3628 " int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename,\n"
3629 " const struct guestfs_add_drive_opts_argv *optargs);\n"
3635 #: ../src/guestfs.pod:1628
3636 msgid "You could call it like this:"
3641 #: ../src/guestfs.pod:1630
3644 " struct guestfs_add_drive_opts_argv optargs = {\n"
3645 " .bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK |\n"
3646 " GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK,\n"
3648 " .format = \"qcow2\"\n"
3655 #: ../src/guestfs.pod:1637
3658 " guestfs_add_drive_opts_argv (g, filename, &optargs);\n"
3664 #: ../src/guestfs.pod:1639 ../src/guestfs-actions.pod:11
3665 #: ../src/guestfs-actions.pod:1858 ../src/guestfs-actions.pod:2779
3666 #: ../fish/guestfish-actions.pod:9 ../fish/guestfish-actions.pod:1262
3667 #: ../fish/guestfish-actions.pod:1898 ../tools/virt-win-reg.pl:704
3673 #: ../src/guestfs.pod:1645
3674 msgid "The C<_BITMASK> suffix on each option name when specifying the bitmask."
3679 #: ../src/guestfs.pod:1650
3680 msgid "You do not need to fill in all fields of the structure."
3685 #: ../src/guestfs.pod:1654
3687 "There must be a one-to-one correspondence between fields of the structure "
3688 "that are filled in, and bits set in the bitmask."
3693 #: ../src/guestfs.pod:1659
3694 msgid "OPTIONAL ARGUMENTS IN OTHER LANGUAGES"
3699 #: ../src/guestfs.pod:1661
3701 "In other languages, optional arguments are expressed in the way that is "
3702 "natural for that language. We refer you to the language-specific "
3703 "documentation for more details on that."
3708 #: ../src/guestfs.pod:1665
3709 msgid "For guestfish, see L<guestfish(1)/OPTIONAL ARGUMENTS>."
3714 #: ../src/guestfs.pod:1667
3715 msgid "SETTING CALLBACKS TO HANDLE EVENTS"
3719 #: ../src/guestfs.pod:1669
3721 "B<Note:> This section documents the generic event mechanism introduced in "
3722 "libguestfs 1.10, which you should use in new code if possible. The old "
3723 "functions C<guestfs_set_log_message_callback>, "
3724 "C<guestfs_set_subprocess_quit_callback>, "
3725 "C<guestfs_set_launch_done_callback>, C<guestfs_set_close_callback> and "
3726 "C<guestfs_set_progress_callback> are no longer documented in this manual "
3727 "page. Because of the ABI guarantee, the old functions continue to work."
3731 #: ../src/guestfs.pod:1678
3733 "Handles generate events when certain things happen, such as log messages "
3734 "being generated, progress messages during long-running operations, or the "
3735 "handle being closed. The API calls described below let you register a "
3736 "callback to be called when events happen. You can register multiple "
3737 "callbacks (for the same, different or overlapping sets of events), and "
3738 "individually remove callbacks. If callbacks are not removed, then they "
3739 "remain in force until the handle is closed."
3743 #: ../src/guestfs.pod:1686
3745 "In the current implementation, events are only generated synchronously: that "
3746 "means that events (and hence callbacks) can only happen while you are in the "
3747 "middle of making another libguestfs call. The callback is called in the "
3752 #: ../src/guestfs.pod:1691
3754 "Events may contain a payload, usually nothing (void), an array of 64 bit "
3755 "unsigned integers, or a message buffer. Payloads are discussed later on."
3759 #: ../src/guestfs.pod:1695
3760 msgid "CLASSES OF EVENTS"
3764 #: ../src/guestfs.pod:1699
3765 msgid "GUESTFS_EVENT_CLOSE (payload type: void)"
3769 #: ../src/guestfs.pod:1702
3771 "The callback function will be called while the handle is being closed "
3772 "(synchronously from L</guestfs_close>)."
3777 #: ../src/guestfs.pod:1705
3779 "Note that libguestfs installs an L<atexit(3)> handler to try to clean up "
3780 "handles that are open when the program exits. This means that this callback "
3781 "might be called indirectly from L<exit(3)>, which can cause unexpected "
3782 "problems in higher-level languages (eg. if your HLL interpreter has already "
3783 "been cleaned up by the time this is called, and if your callback then jumps "
3784 "into some HLL function)."
3788 #: ../src/guestfs.pod:1712
3790 "If no callback is registered: the handle is closed without any callback "
3795 #: ../src/guestfs.pod:1715
3796 msgid "GUESTFS_EVENT_SUBPROCESS_QUIT (payload type: void)"
3800 #: ../src/guestfs.pod:1718
3802 "The callback function will be called when the child process quits, either "
3803 "asynchronously or if killed by L</guestfs_kill_subprocess>. (This "
3804 "corresponds to a transition from any state to the CONFIG state)."
3808 #: ../src/guestfs.pod:1722 ../src/guestfs.pod:1731
3809 msgid "If no callback is registered: the event is ignored."
3813 #: ../src/guestfs.pod:1724
3814 msgid "GUESTFS_EVENT_LAUNCH_DONE (payload type: void)"
3818 #: ../src/guestfs.pod:1727
3820 "The callback function will be called when the child process becomes ready "
3821 "first time after it has been launched. (This corresponds to a transition "
3822 "from LAUNCHING to the READY state)."
3826 #: ../src/guestfs.pod:1733
3827 msgid "GUESTFS_EVENT_PROGRESS (payload type: array of 4 x uint64_t)"
3832 #: ../src/guestfs.pod:1736
3834 "Some long-running operations can generate progress messages. If this "
3835 "callback is registered, then it will be called each time a progress message "
3836 "is generated (usually two seconds after the operation started, and three "
3837 "times per second thereafter until it completes, although the frequency may "
3838 "change in future versions)."
3842 #: ../src/guestfs.pod:1742
3844 "The callback receives in the payload four unsigned 64 bit numbers which are "
3845 "(in order): C<proc_nr>, C<serial>, C<position>, C<total>."
3849 #: ../src/guestfs.pod:1745
3851 "The units of C<total> are not defined, although for some operations C<total> "
3852 "may relate in some way to the amount of data to be transferred (eg. in bytes "
3853 "or megabytes), and C<position> may be the portion which has been transferred."
3858 #: ../src/guestfs.pod:1750
3859 msgid "The only defined and stable parts of the API are:"
3864 #: ../src/guestfs.pod:1756
3866 "The callback can display to the user some type of progress bar or indicator "
3867 "which shows the ratio of C<position>:C<total>."
3872 #: ../src/guestfs.pod:1761
3873 msgid "0 E<lt>= C<position> E<lt>= C<total>"
3877 #: ../src/guestfs.pod:1765
3879 "If any progress notification is sent during a call, then a final progress "
3880 "notification is always sent when C<position> = C<total> (I<unless> the call "
3881 "fails with an error)."
3886 #: ../src/guestfs.pod:1769
3888 "This is to simplify caller code, so callers can easily set the progress "
3889 "indicator to \"100%\" at the end of the operation, without requiring special "
3890 "code to detect this case."
3894 #: ../src/guestfs.pod:1775
3896 "For some calls we are unable to estimate the progress of the call, but we "
3897 "can still generate progress messages to indicate activity. This is known as "
3898 "\"pulse mode\", and is directly supported by certain progress bar "
3899 "implementations (eg. GtkProgressBar)."
3903 #: ../src/guestfs.pod:1780
3905 "For these calls, zero or more progress messages are generated with "
3906 "C<position = 0> and C<total = 1>, followed by a final message with "
3907 "C<position = total = 1>."
3911 #: ../src/guestfs.pod:1784
3913 "As noted above, if the call fails with an error then the final message may "
3918 #: ../src/guestfs.pod:1789
3920 "The callback also receives the procedure number (C<proc_nr>) and serial "
3921 "number (C<serial>) of the call. These are only useful for debugging "
3922 "protocol issues, and the callback can normally ignore them. The callback "
3923 "may want to print these numbers in error messages or debugging messages."
3927 #: ../src/guestfs.pod:1795
3928 msgid "If no callback is registered: progress messages are discarded."
3932 #: ../src/guestfs.pod:1797
3933 msgid "GUESTFS_EVENT_APPLIANCE (payload type: message buffer)"
3937 #: ../src/guestfs.pod:1800
3939 "The callback function is called whenever a log message is generated by qemu, "
3940 "the appliance kernel, guestfsd (daemon), or utility programs."
3944 #: ../src/guestfs.pod:1803
3946 "If the verbose flag (L</guestfs_set_verbose>) is set before launch (L</"
3947 "guestfs_launch>) then additional debug messages are generated."
3951 #: ../src/guestfs.pod:1806 ../src/guestfs.pod:1820
3953 "If no callback is registered: the messages are discarded unless the verbose "
3954 "flag is set in which case they are sent to stderr. You can override the "
3955 "printing of verbose messages to stderr by setting up a callback."
3959 #: ../src/guestfs.pod:1811
3960 msgid "GUESTFS_EVENT_LIBRARY (payload type: message buffer)"
3964 #: ../src/guestfs.pod:1814
3966 "The callback function is called whenever a log message is generated by the "
3967 "library part of libguestfs."
3971 #: ../src/guestfs.pod:1817
3973 "If the verbose flag (L</guestfs_set_verbose>) is set then additional debug "
3974 "messages are generated."
3978 #: ../src/guestfs.pod:1825
3979 msgid "GUESTFS_EVENT_TRACE (payload type: message buffer)"
3983 #: ../src/guestfs.pod:1828
3985 "The callback function is called whenever a trace message is generated. This "
3986 "only applies if the trace flag (L</guestfs_set_trace>) is set."
3990 #: ../src/guestfs.pod:1831
3992 "If no callback is registered: the messages are sent to stderr. You can "
3993 "override the printing of trace messages to stderr by setting up a callback."
3997 #: ../src/guestfs.pod:1837
3998 msgid "guestfs_set_event_callback"
4002 #: ../src/guestfs.pod:1839
4005 " int guestfs_set_event_callback (guestfs_h *g,\n"
4006 " guestfs_event_callback cb,\n"
4007 " uint64_t event_bitmask,\n"
4014 #: ../src/guestfs.pod:1845
4016 "This function registers a callback (C<cb>) for all event classes in the "
4021 #: ../src/guestfs.pod:1848
4023 "For example, to register for all log message events, you could call this "
4024 "function with the bitmask C<GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_LIBRARY>. "
4025 "To register a single callback for all possible classes of events, use "
4026 "C<GUESTFS_EVENT_ALL>."
4030 #: ../src/guestfs.pod:1854
4031 msgid "C<flags> should always be passed as 0."
4035 #: ../src/guestfs.pod:1856
4037 "C<opaque> is an opaque pointer which is passed to the callback. You can use "
4038 "it for any purpose."
4042 #: ../src/guestfs.pod:1859
4044 "The return value is the event handle (an integer) which you can use to "
4045 "delete the callback (see below)."
4049 #: ../src/guestfs.pod:1862
4051 "If there is an error, this function returns C<-1>, and sets the error in the "
4052 "handle in the usual way (see L</guestfs_last_error> etc.)"
4056 #: ../src/guestfs.pod:1865
4058 "Callbacks remain in effect until they are deleted, or until the handle is "
4063 #: ../src/guestfs.pod:1868
4065 "In the case where multiple callbacks are registered for a particular event "
4066 "class, all of the callbacks are called. The order in which multiple "
4067 "callbacks are called is not defined."
4071 #: ../src/guestfs.pod:1872
4072 msgid "guestfs_delete_event_callback"
4076 #: ../src/guestfs.pod:1874
4079 " void guestfs_delete_event_callback (guestfs_h *g, int event_handle);\n"
4084 #: ../src/guestfs.pod:1876
4086 "Delete a callback that was previously registered. C<event_handle> should be "
4087 "the integer that was returned by a previous call to "
4088 "C<guestfs_set_event_callback> on the same handle."
4092 #: ../src/guestfs.pod:1880
4093 msgid "guestfs_event_callback"
4097 #: ../src/guestfs.pod:1882
4100 " typedef void (*guestfs_event_callback) (\n"
4103 " uint64_t event,\n"
4104 " int event_handle,\n"
4106 " const char *buf, size_t buf_len,\n"
4107 " const uint64_t *array, size_t array_len);\n"
4112 #: ../src/guestfs.pod:1891
4114 "This is the type of the event callback function that you have to provide."
4118 #: ../src/guestfs.pod:1894
4120 "The basic parameters are: the handle (C<g>), the opaque user pointer "
4121 "(C<opaque>), the event class (eg. C<GUESTFS_EVENT_PROGRESS>), the event "
4122 "handle, and C<flags> which in the current API you should ignore."
4126 #: ../src/guestfs.pod:1898
4128 "The remaining parameters contain the event payload (if any). Each event may "
4129 "contain a payload, which usually relates to the event class, but for future "
4130 "proofing your code should be written to handle any payload for any event "
4135 #: ../src/guestfs.pod:1903
4137 "C<buf> and C<buf_len> contain a message buffer (if C<buf_len == 0>, then "