From: Richard Jones Date: Wed, 28 Jul 2010 22:11:38 +0000 (+0100) Subject: New APIs: findfs-label and findfs-uuid X-Git-Tag: 1.5.3~5 X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=commitdiff_plain;h=65e9ac4595fbace8f301030469932be518456246;hp=ad4cff2625651bda9de25de9aba96bdf213d0a0a New APIs: findfs-label and findfs-uuid These two calls wrap up the /sbin/findfs command, allowing you to find a filesystem by only knowing its label or UUID. This is especially useful when resolving LABEL=... or UUID=... entries in /etc/fstab. Sample guestfish session: > vfs-uuid /dev/vda1 277dd61c-bf34-4253-a8dc-df500a05e7df > findfs-uuid 277dd61c-bf34-4253-a8dc-df500a05e7df /dev/vda1 > vfs-label /dev/vda1 /boot > findfs-label /boot /dev/vda1 > vfs-uuid /dev/VolGroup00/LogVol00 40ce7c36-82ce-4a12-a99d-48f5e054162c > findfs-uuid 40ce7c36-82ce-4a12-a99d-48f5e054162c /dev/mapper/VolGroup00-LogVol00 > findfs-uuid 12345678 libguestfs: error: findfs_uuid: findfs: unable to resolve 'UUID=12345678' --- diff --git a/daemon/Makefile.am b/daemon/Makefile.am index 27fca2a..0c8be08 100644 --- a/daemon/Makefile.am +++ b/daemon/Makefile.am @@ -84,6 +84,7 @@ guestfsd_SOURCES = \ ext2.c \ fallocate.c \ file.c \ + findfs.c \ fill.c \ find.c \ fsck.c \ diff --git a/daemon/findfs.c b/daemon/findfs.c new file mode 100644 index 0000000..0520f18 --- /dev/null +++ b/daemon/findfs.c @@ -0,0 +1,72 @@ +/* libguestfs - the guestfsd daemon + * Copyright (C) 2010 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include + +#include +#include +#include +#include + +#include "daemon.h" +#include "actions.h" + +static char * +findfs (const char *tag, const char *label_or_uuid) +{ + /* Kill the cache file, forcing blkid to reread values from the + * original filesystems. In blkid there is a '-p' option which is + * supposed to do this, but (a) it doesn't work and (b) that option + * is not supported in RHEL 5. + */ + unlink ("/etc/blkid/blkid.tab"); + + size_t len = strlen (tag) + strlen (label_or_uuid) + 2; + char arg[len]; + snprintf (arg, len, "%s=%s", tag, label_or_uuid); + + char *out, *err; + int r = command (&out, &err, "findfs", arg, NULL); + if (r == -1) { + reply_with_error ("%s", err); + free (out); + free (err); + return NULL; + } + + free (err); + + /* Trim trailing \n if present. */ + len = strlen (out); + if (len > 0 && out[len-1] == '\n') + out[len-1] = '\0'; + + return out; /* caller frees */ +} + +char * +do_findfs_uuid (const char *uuid) +{ + return findfs ("UUID", uuid); +} + +char * +do_findfs_label (const char *label) +{ + return findfs ("LABEL", label); +} diff --git a/po/POTFILES.in b/po/POTFILES.in index bf066ea..8ce5c97 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -21,6 +21,7 @@ daemon/fallocate.c daemon/file.c daemon/fill.c daemon/find.c +daemon/findfs.c daemon/fsck.c daemon/glob.c daemon/grep.c diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR index 10b0c0d..c1d1ffb 100644 --- a/src/MAX_PROC_NR +++ b/src/MAX_PROC_NR @@ -1 +1 @@ -264 +266 diff --git a/src/generator.ml b/src/generator.ml index 77c7642..4ce49fe 100755 --- a/src/generator.ml +++ b/src/generator.ml @@ -4952,7 +4952,9 @@ a file in the host and attach it as a device."); This returns the filesystem label of the filesystem on C. -If the filesystem is unlabeled, this returns the empty string."); +If the filesystem is unlabeled, this returns the empty string. + +To find a filesystem from the label, use C."); ("vfs_uuid", (RString "uuid", [Device "device"]), 254, [], (let uuid = uuidgen () in @@ -4964,7 +4966,9 @@ If the filesystem is unlabeled, this returns the empty string."); This returns the filesystem UUID of the filesystem on C. -If the filesystem does not have a UUID, this returns the empty string."); +If the filesystem does not have a UUID, this returns the empty string. + +To find a filesystem from the UUID, use C."); ("lvm_set_filter", (RErr, [DeviceList "devices"]), 255, [Optional "lvm2"], (* Can't be tested with the current framework because @@ -5091,6 +5095,26 @@ I keys."); This command tests whether C is a logical volume, and returns true iff this is the case."); + ("findfs_uuid", (RString "device", [String "uuid"]), 265, [], + [], + "find a filesystem by UUID", + "\ +This command searches the filesystems and returns the one +which has the given UUID. An error is returned if no such +filesystem can be found. + +To find the UUID of a filesystem, use C."); + + ("findfs_label", (RString "device", [String "label"]), 266, [], + [], + "find a filesystem by label", + "\ +This command searches the filesystems and returns the one +which has the given label. An error is returned if no such +filesystem can be found. + +To find the label of a filesystem, use C."); + ] let all_functions = non_daemon_functions @ daemon_functions