[Libguestfs] [PATCH 02/10] New API: disk-create for creating blank disks.

This is a wrapper around either 'qemu-img create' or calls to open, truncate and posix_fallocate which litter and complicate existing code. --- Makefile.am | 1 + configure.ac | 1 + generator/actions.ml | 52 ++++++- gobject/Makefile.inc | 2 + po/POTFILES | 2 + src/Makefile.am | 1 + src/create.c | 319 +++++++++++++++++++++++++++++++++++++++ tests/create/Makefile.am | 27 ++++ tests/create/test-disk-create.sh | 48 ++++++ 9 files changed, 451 insertions(+), 2 deletions(-) create mode 100644 src/create.c create mode 100644 tests/create/Makefile.am create mode 100755 tests/create/test-disk-create.sh diff --git a/Makefile.am b/Makefile.am index e39d11f..5b8f109 100644 --- a/Makefile.am +++ b/Makefile.am @@ -39,6 +39,7 @@ SUBDIRS += tests/tmpdirs SUBDIRS += tests/protocol SUBDIRS += tests/events SUBDIRS += tests/parallel +SUBDIRS += tests/create SUBDIRS += tests/disks SUBDIRS += tests/mountable SUBDIRS += tests/network diff --git a/configure.ac b/configure.ac index c07462e..df8e962 100644 --- a/configure.ac +++ b/configure.ac @@ -1745,6 +1745,7 @@ AC_CONFIG_FILES([Makefile tests/btrfs/Makefile tests/c-api/Makefile tests/charsets/Makefile + tests/create/Makefile tests/data/Makefile tests/disks/Makefile tests/disks/test-qemu-drive-libvirt.xml diff --git a/generator/actions.ml b/generator/actions.ml index fa1a2c5..3637da0 100644 --- a/generator/actions.ml +++ b/generator/actions.ml @@ -3093,6 +3093,54 @@ Return the current backend settings. See L<guestfs(3)/BACKEND>, L<guestfs(3)/BACKEND SETTINGS>." }; + { defaults with + name = "disk_create"; + style = RErr, [String "filename"; String "format"; Int64 "size"], [OString "backingfile"; OString "backingformat"; OString "preallocation"; OString "compat"; OInt "clustersize"]; + test_excuse = "tests in tests/create subdirectory"; + shortdesc = "create a blank disk image"; + longdesc = "\ +Create a blank disk image called C<filename> (a host file or device) +with format C<format> (usually C<raw> or C<qcow2>, but other formats +are possible). The size is C<size> bytes. + +If used with the optional C<backingfile> parameter, then a snapshot +is created on top of the backing file. In this case, C<size> must +be passed as C<-1>. The size of the snapshot is the same as the +size of the backing file, which is discovered automatically. You +are encouraged to also pass C<backingformat> to describe the format +of C<backingfile>. + +The other optional parameters are: + +=over 4 + +=item C<preallocation> + +If format is C<raw>, then this can be either C<sparse> or C<full> +to create a sparse or fully allocated file respectively. The default +is C<sparse>. + +If format is C<qcow2>, then this can be either C<off> or +C<metadata>. Preallocating metadata can be faster when doing lots +of writes, but uses more space. + +=item C<compat> + +C<qcow2> only: +Pass the string C<1.1> to use the advanced qcow2 format supported +by qemu E<ge> 1.1. + +=item C<clustersize> + +C<qcow2> only: +Change the qcow2 cluster size. The default is 65536 (bytes) and +this settig may be any power of two between 512 and 2097152. + +=back + +Note that this call does not add the new disk to the handle. You +may need to call C<guestfs_add_drive_opts> separately." }; + ] (* daemon_functions are any functions which cause some action @@ -11739,7 +11787,7 @@ let fish_commands = [ This creates an empty (zeroed) file of the given size, and then adds so it can be further examined. -For more advanced image creation, see L<qemu-img(1)> utility. +For more advanced image creation, see L</disk-create>. Size can be specified using standard suffixes, eg. C<1M>. @@ -11983,7 +12031,7 @@ not assigned to the file until they are needed. Sparse disk files only use space when written to, but they are slower and there is a danger you could run out of real disk space during a write operation. -For more advanced image creation, see L<qemu-img(1)> utility. +For more advanced image creation, see L</disk-create>. Size can be specified using standard suffixes, eg. C<1M>. diff --git a/gobject/Makefile.inc b/gobject/Makefile.inc index 7024754..7a8493a 100644 --- a/gobject/Makefile.inc +++ b/gobject/Makefile.inc @@ -52,6 +52,7 @@ guestfs_gobject_headers= \ include/guestfs-gobject/optargs-mount_local.h \ include/guestfs-gobject/optargs-umount_local.h \ include/guestfs-gobject/optargs-add_drive_scratch.h \ + include/guestfs-gobject/optargs-disk_create.h \ include/guestfs-gobject/optargs-is_file.h \ include/guestfs-gobject/optargs-is_dir.h \ include/guestfs-gobject/optargs-umount.h \ @@ -127,6 +128,7 @@ guestfs_gobject_sources= \ src/optargs-mount_local.c \ src/optargs-umount_local.c \ src/optargs-add_drive_scratch.c \ + src/optargs-disk_create.c \ src/optargs-is_file.c \ src/optargs-is_dir.c \ src/optargs-umount.c \ diff --git a/po/POTFILES b/po/POTFILES index c6277e9..76d1b1d 100644 --- a/po/POTFILES +++ b/po/POTFILES @@ -170,6 +170,7 @@ gobject/src/optargs-copy_device_to_device.c gobject/src/optargs-copy_device_to_file.c gobject/src/optargs-copy_file_to_device.c gobject/src/optargs-copy_file_to_file.c +gobject/src/optargs-disk_create.c gobject/src/optargs-e2fsck.c gobject/src/optargs-fstrim.c gobject/src/optargs-grep.c @@ -267,6 +268,7 @@ src/canonical-name.c src/cleanup.c src/command.c src/conn-socket.c +src/create.c src/dbdump.c src/drives.c src/errnostring-gperf.c diff --git a/src/Makefile.am b/src/Makefile.am index ba02061..4475281 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -90,6 +90,7 @@ libguestfs_la_SOURCES = \ canonical-name.c \ command.c \ conn-socket.c \ + create.c \ dbdump.c \ drives.c \ errors.c \ diff --git a/src/create.c b/src/create.c new file mode 100644 index 0000000..18c4402 --- /dev/null +++ b/src/create.c @@ -0,0 +1,319 @@ +/* libguestfs + * Copyright (C) 2012 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <inttypes.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <errno.h> + +#include "guestfs.h" +#include "guestfs-internal.h" +#include "guestfs-internal-actions.h" +#include "guestfs_protocol.h" + +static int disk_create_raw (guestfs_h *g, const char *filename, int64_t size, const struct guestfs_disk_create_argv *optargs); +static int disk_create_qcow2 (guestfs_h *g, const char *filename, int64_t size, const char *backingfile, const struct guestfs_disk_create_argv *optargs); +static char *qemu_escape_param (guestfs_h *g, const char *param); + +int +guestfs__disk_create (guestfs_h *g, const char *filename, + const char *format, int64_t size, + const struct guestfs_disk_create_argv *optargs) +{ + const char *backingfile; + + backingfile = optargs->bitmask & GUESTFS_DISK_CREATE_BACKINGFILE_BITMASK ? + optargs->backingfile : NULL; + + /* Ensure size is valid. */ + if (backingfile) { + if (size != -1) { + error (g, _("if using a backing file, size must be passed as -1")); + return -1; + } + } else { + /* XXX Actually size == 0 could be valid, although not useful and + * it causes qemu to break. + */ + if (size <= 0) { + error (g, _("invalid size: %" PRIi64), size); + return -1; + } + } + + /* Now the format-specific code. */ + if (STREQ (format, "raw")) { + if (backingfile) { + error (g, _("backingfile cannot be used for raw format disks")); + return -1; + } + if (disk_create_raw (g, filename, size, optargs) == -1) + return -1; + } + else if (STREQ (format, "qcow2")) { + if (disk_create_qcow2 (g, filename, size, backingfile, optargs) == -1) + return -1; + } + else { + /* Be conservative about what formats we support, since we don't + * want to make unlimited promises through the API. We can always + * add more later. + */ + error (g, _("unsupported format '%s'"), format); + return -1; + } + + return 0; +} + +static int +disk_create_raw (guestfs_h *g, const char *filename, int64_t size, + const struct guestfs_disk_create_argv *optargs) +{ + int allocated = 0; + int fd; + struct stat statbuf; + + /* backingfile parameter not present checked above */ + + if (optargs->bitmask & GUESTFS_DISK_CREATE_BACKINGFORMAT_BITMASK) { + error (g, _("backingformat parameter cannot be used with raw format")); + return -1; + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_PREALLOCATION_BITMASK) { + if (STREQ (optargs->preallocation, "sparse")) + allocated = 0; + else if (STREQ (optargs->preallocation, "full")) + allocated = 1; + else { + error (g, _("invalid value for preallocation parameter '%s'"), + optargs->preallocation); + return -1; + } + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_COMPAT_BITMASK) { + error (g, _("compat parameter cannot be used with raw format")); + return -1; + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_CLUSTERSIZE_BITMASK) { + error (g, _("clustersize parameter cannot be used with raw format")); + return -1; + } + + /* This version refuses the overwrite block devices or char devices. + * XXX It would be possible to make it work with block devices. + */ + if (stat (filename, &statbuf) == 0) { + if (S_ISBLK (statbuf.st_mode)) { + error (g, _("refusing to overwrite block device '%s'"), filename); + return -1; + } + if (S_ISCHR (statbuf.st_mode)) { + error (g, _("refusing to overwrite char device '%s'"), filename); + return -1; + } + } + + fd = open (filename, O_WRONLY|O_CREAT|O_NOCTTY|O_TRUNC|O_CLOEXEC, 0666); + if (fd == -1) { + perrorf (g, _("cannot create raw file: %s"), filename); + return -1; + } + + if (!allocated) { /* Sparse file. */ + if (ftruncate (fd, size) == -1) { + perrorf (g, _("%s: truncate"), filename); + close (fd); + unlink (filename); + return -1; + } + } + else { /* Allocated file. */ +#ifdef HAVE_POSIX_FALLOCATE + int err; + + err = posix_fallocate (fd, 0, size); + if (err != 0) { + errno = err; + perrorf (g, _("%s: fallocate"), filename); + close (fd); + unlink (filename); + return -1; + } +#else + /* Slow emulation of posix_fallocate on platforms which don't have it. */ + char buffer[BUFSIZ]; + size_t remaining = size; + size_t n; + ssize_t r; + + memset (buffer, 0, sizeof buffer); + + while (remaining > 0) { + n = remaining > sizeof buffer ? sizeof buffer : remaining; + r = write (fd, buffer, n); + if (r == -1) { + perrorf (g, _("%s: write"), filename); + close (fd); + unlink (filename); + return -1; + } + remaining -= r; + } +#endif + } + + if (close (fd) == -1) { + perrorf (g, _("%s: close"), filename); + unlink (filename); + return -1; + } + + return 0; +} + +/* http://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2 */ +static int +is_power_of_2 (unsigned v) +{ + return v && ((v & (v - 1)) == 0); +} + +static int +disk_create_qcow2 (guestfs_h *g, const char *orig_filename, int64_t size, + const char *backingfile, + const struct guestfs_disk_create_argv *optargs) +{ + CLEANUP_FREE char *filename = NULL; + const char *backingformat = NULL; + const char *preallocation = NULL; + const char *compat = NULL; + int clustersize = -1; + CLEANUP_FREE_STRINGSBUF DECLARE_STRINGSBUF (optionsv); + CLEANUP_CMD_CLOSE struct command *cmd = guestfs___new_command (g); + int r; + + /* If the filename is something like "file:foo" then qemu-img will + * try to interpret that as "foo" in the file:/// protocol. To + * avoid that, if the path is relative prefix it with "./" since + * qemu-img won't try to interpret such a path. + */ + if (orig_filename[0] != '/') + filename = safe_asprintf (g, "./%s", orig_filename); + else + filename = safe_strdup (g, orig_filename); + + if (optargs->bitmask & GUESTFS_DISK_CREATE_BACKINGFORMAT_BITMASK) { + backingformat = optargs->backingformat; + if (STRNEQ (backingformat, "raw") && STRNEQ (backingformat, "qcow2")) { + error (g, _("invalid value for backingformat parameter '%s'"), + backingformat); + return -1; + } + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_PREALLOCATION_BITMASK) { + preallocation = optargs->preallocation; + if (STRNEQ (preallocation, "off") && STRNEQ (preallocation, "metadata")) { + error (g, _("invalid value for preallocation parameter '%s'"), + preallocation); + return -1; + } + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_COMPAT_BITMASK) { + compat = optargs->compat; + if (STRNEQ (compat, "0.10") && STRNEQ (compat, "1.1")) { + error (g, _("invalid value for compat parameter '%s'"), compat); + return -1; + } + } + if (optargs->bitmask & GUESTFS_DISK_CREATE_CLUSTERSIZE_BITMASK) { + clustersize = optargs->clustersize; + if (clustersize < 512 || clustersize > 2097152 || + !is_power_of_2 ((unsigned) clustersize)) { + error (g, _("invalid value for clustersize parameter '%d'"), + clustersize); + return -1; + } + } + + /* Assemble the qemu-img command line. */ + guestfs___cmd_add_arg (cmd, "qemu-img"); + guestfs___cmd_add_arg (cmd, "create"); + guestfs___cmd_add_arg (cmd, "-f"); + guestfs___cmd_add_arg (cmd, "qcow2"); + + /* -o parameter. */ + if (backingfile) { + CLEANUP_FREE char *p = qemu_escape_param (g, backingfile); + guestfs___add_sprintf (g, &optionsv, "backing_file=%s", p); + } + if (backingformat) + guestfs___add_sprintf (g, &optionsv, "backing_fmt=%s", backingformat); + if (preallocation) + guestfs___add_sprintf (g, &optionsv, "preallocation=%s", preallocation); + if (compat) + guestfs___add_sprintf (g, &optionsv, "compat=%s", compat); + if (clustersize >= 0) + guestfs___add_sprintf (g, &optionsv, "cluster_size=%d", clustersize); + guestfs___end_stringsbuf (g, &optionsv); + + if (optionsv.size > 1) { + CLEANUP_FREE char *options = guestfs___join_strings (",", optionsv.argv); + guestfs___cmd_add_arg (cmd, "-o"); + guestfs___cmd_add_arg (cmd, options); + } + + /* Complete the command line. */ + guestfs___cmd_add_arg (cmd, filename); + if (size >= 0) + guestfs___cmd_add_arg_format (cmd, "%" PRIi64, size); + + r = guestfs___cmd_run (cmd); + if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) { + guestfs___external_command_failed (g, r, "qemu-img", orig_filename); + return -1; + } + + return 0; +} + +/* XXX Duplicated in launch-direct.c. */ +static char * +qemu_escape_param (guestfs_h *g, const char *param) +{ + size_t i, len = strlen (param); + char *p, *ret; + + ret = p = safe_malloc (g, len*2 + 1); /* max length of escaped name*/ + for (i = 0; i < len; ++i) { + *p++ = param[i]; + if (param[i] == ',') + *p++ = ','; + } + *p = '\0'; + + return ret; +} diff --git a/tests/create/Makefile.am b/tests/create/Makefile.am new file mode 100644 index 0000000..cdcecd2 --- /dev/null +++ b/tests/create/Makefile.am @@ -0,0 +1,27 @@ +# libguestfs +# Copyright (C) 2014 Red Hat Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +include $(top_srcdir)/subdir-rules.mk + +TESTS = \ + test-disk-create.sh + +TESTS_ENVIRONMENT = \ + $(top_builddir)/run --test + +EXTRA_DIST = \ + $(TESTS) diff --git a/tests/create/test-disk-create.sh b/tests/create/test-disk-create.sh new file mode 100755 index 0000000..b287233 --- /dev/null +++ b/tests/create/test-disk-create.sh @@ -0,0 +1,48 @@ +#!/bin/bash +# Copyright (C) 2014 Red Hat Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +# Test the disk-create API. + +export LANG=C + +set -e + +rm -f disk*.img file:*.img + +# XXX We should also test failure paths. + +../../fish/guestfish <<EOF + disk-create disk1.img raw 256K + disk-create disk2.img raw 256K preallocation:sparse + disk-create disk3.img raw 256K preallocation:full + disk-create disk4.img qcow2 256K + disk-create disk5.img qcow2 256K preallocation:off + disk-create disk6.img qcow2 256K preallocation:metadata + disk-create disk7.img qcow2 256K compat:1.1 + disk-create disk8.img qcow2 256K clustersize:128K + disk-create disk9.img qcow2 -1 backingfile:disk1.img compat:1.1 + disk-create disk10.img qcow2 -1 backingfile:disk2.img backingformat:raw + disk-create disk11.img qcow2 -1 backingfile:disk4.img backingformat:qcow2 + + # Some annoying corner-cases in qemu-img. + disk-create disk:0.img qcow2 256K + disk-create file:0.img qcow2 256K + disk-create disk,0.img qcow2 256K + disk-create disk,,0.img qcow2 256K +EOF + +rm disk*.img file:*.img -- 1.8.4.2