mirror of
https://github.com/libguestfs/libguestfs.git
synced 2026-03-21 22:53:37 +00:00
daemon: Reimplement handling of lvm.conf and filters.
LVM is fine with a completely empty configuration file (meaning "all defaults"), so start with one instead of copying the system configuration file. Also this means we can very easily implement lvm_set_filter functionality without using Augeas, since we no longer have to worry about existing filters being present. Thanks: Alasdair Kergon, Zdenek Kabelac.
This commit is contained in:
Richard W.M. Jones
@@ -32,7 +32,6 @@ include $(top_srcdir)/subdir-rules.mk
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EXTRA_DIST = \
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99-guestfs-serial.rules \
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excludefiles.in \
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guestfs_lvm_conf.aug \
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guestfs_shadow.aug \
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hostfiles.in \
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init \
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@@ -87,12 +86,11 @@ packagelist: packagelist.in Makefile
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cmp -s $@ $@-t || mv $@-t $@
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rm -f $@-t
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supermin.d/daemon.tar.gz: ../daemon/guestfsd guestfs_lvm_conf.aug guestfs_shadow.aug
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supermin.d/daemon.tar.gz: ../daemon/guestfsd guestfs_shadow.aug
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rm -f $@ $@-t
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rm -rf tmp-d
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mkdir -p tmp-d$(DAEMON_SUPERMIN_DIR) tmp-d/etc tmp-d/usr/share/guestfs
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ln ../daemon/guestfsd tmp-d$(DAEMON_SUPERMIN_DIR)/guestfsd
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ln $(srcdir)/guestfs_lvm_conf.aug tmp-d/usr/share/guestfs/guestfs_lvm_conf.aug
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ln $(srcdir)/guestfs_shadow.aug tmp-d/usr/share/guestfs/guestfs_shadow.aug
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( cd tmp-d && tar zcf - * ) > $@-t
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rm -r tmp-d
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@@ -1,74 +0,0 @@
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(*
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Module: LVM
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Parses LVM metadata.
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Author: Gabriel de Perthuis <g2p.code+augeas@gmail.com>
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About: License
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This file is licensed under the LGPL v2+.
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About: Configuration files
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This lens applies to files in /etc/lvm/backup and /etc/lvm/archive.
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About: Examples
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The <Test_LVM> file contains various examples and tests.
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*)
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module Guestfs_LVM_conf =
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autoload xfm
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(* See lvm2/libdm/libdm-config.c for tokenisation;
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* libdm uses a blacklist but I prefer the safer whitelist approach. *)
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(* View: identifier
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* The left hand side of a definition *)
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let identifier = /[a-zA-Z0-9_-]+/
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(* strings can contain backslash-escaped dquotes, but I don't know
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* how to get the message across to augeas *)
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let str = [label "str". Quote.do_dquote (store /([^\"]|\\\\.)*/)]
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let int = [label "int". store Rx.relinteger]
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(* View: flat_literal
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* A literal without structure *)
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let flat_literal = int|str
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(* allow multiline and mixed int/str, used for raids and stripes *)
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(* View: list
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* A list containing flat literals *)
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let list = [
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label "list" . counter "list"
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. del /\[[ \t\n]*/ "["
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.([seq "list". flat_literal . del /,[ \t\n]*/ ", "]*
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. [seq "list". flat_literal . del /[ \t\n]*/ ""])?
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. Util.del_str "]"]
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(* View: val
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* Any value that appears on the right hand side of an assignment *)
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let val = flat_literal | list
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(* View: nondef
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* A line that doesn't contain a statement *)
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let nondef =
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Util.empty
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| Util.comment
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(* Build.block couldn't be reused, because of recursion and
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* a different philosophy of whitespace handling. *)
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(* View: def
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* An assignment, or a block containing definitions *)
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let rec def = [
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Util.indent . key identifier . (
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del /[ \t]*\{\n/ " {\n"
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.[label "dict".(nondef | def)*]
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. Util.indent . Util.del_str "}\n"
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|Sep.space_equal . val . Util.comment_or_eol)]
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(* View: lns
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* The main lens *)
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let lns = (nondef | def)*
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let filter =
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incl "/etc/lvm/archive/*.vg"
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. incl "/etc/lvm/backup/*"
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. Util.stdexcl
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let xfm = transform lns filter
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@@ -253,7 +253,7 @@ extern char *get_blkid_tag (const char *device, const char *tag);
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extern int lv_canonical (const char *device, char **ret);
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/* lvm-filter.c */
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extern void copy_lvm (void);
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extern void clean_lvm_config (void);
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extern void start_lvmetad (void);
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/* zero.c */
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@@ -269,7 +269,7 @@ main (int argc, char *argv[])
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* daemon/lvm-filter.c).
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*/
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if (!test_mode) {
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copy_lvm ();
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clean_lvm_config ();
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start_lvmetad ();
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}
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@@ -36,65 +36,47 @@
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#include "daemon.h"
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#include "actions.h"
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/* This runs during daemon start up and creates a complete copy of
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* /etc/lvm so that we can modify it as we desire. We set
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* LVM_SYSTEM_DIR to point to the copy. Note that the final directory
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* layout is:
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/* This runs during daemon start up and creates a fresh LVM
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* configuration which we can modify as we desire. LVM allows
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* configuration to be completely empty (meaning "all defaults").
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*
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* The final directory layout is:
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*
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* /tmp/lvmXXXXXX (lvm_system_dir set to this)
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* /tmp/lvmXXXXXX/lvm ($LVM_SYSTEM_DIR set to this)
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* /tmp/lvmXXXXXX/lvm/lvm.conf (configuration file)
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* /tmp/lvmXXXXXX/lvm/cache
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* etc.
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* /tmp/lvmXXXXXX/lvm/lvm.conf (configuration file - initially empty)
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*/
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static char lvm_system_dir[] = "/tmp/lvmXXXXXX";
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static void rm_lvm_system_dir (void);
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static void debug_lvm_config (void);
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void
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copy_lvm (void)
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clean_lvm_config (void)
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{
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struct stat statbuf;
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char cmd[64], env[64];
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int r;
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/* If /etc/lvm directory doesn't exist (or isn't a directory) assume
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* that this system doesn't support LVM and do nothing.
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*/
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r = stat ("/etc/lvm", &statbuf);
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if (r == -1) {
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perror ("copy_lvm: stat: /etc/lvm");
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return;
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}
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if (! S_ISDIR (statbuf.st_mode)) {
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fprintf (stderr, "copy_lvm: warning: /etc/lvm is not a directory\n");
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return;
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}
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char env[64], conf[64];
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FILE *fp;
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if (mkdtemp (lvm_system_dir) == NULL)
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error (EXIT_FAILURE, errno, "mkdtemp: %s", lvm_system_dir);
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/* Copy the entire directory */
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snprintf (cmd, sizeof cmd, "%s -a /etc/lvm/ %s", "cp", lvm_system_dir);
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r = system (cmd);
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if (r == -1) {
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perror (cmd);
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rmdir (lvm_system_dir);
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exit (EXIT_FAILURE);
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}
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if (WEXITSTATUS (r) != 0) {
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fprintf (stderr, "cp command failed with return code %d\n",
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WEXITSTATUS (r));
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rmdir (lvm_system_dir);
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exit (EXIT_FAILURE);
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}
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/* Set environment variable so we use the copy. */
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snprintf (env, sizeof env, "%s/lvm", lvm_system_dir);
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mkdir (env, 0755);
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snprintf (conf, sizeof conf, "%s/lvm/lvm.conf", lvm_system_dir);
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fp = fopen (conf, "w");
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if (fp == NULL) {
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perror ("clean_lvm_config: cannot create empty lvm.conf");
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exit (EXIT_FAILURE);
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}
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fclose (fp);
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/* Set environment variable so we use the clean configuration. */
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setenv ("LVM_SYSTEM_DIR", env, 1);
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/* Set a handler to remove the temporary directory at exit. */
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atexit (rm_lvm_system_dir);
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debug_lvm_config ();
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}
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/* Try to run lvmetad, without failing if it couldn't. */
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@@ -125,98 +107,40 @@ rm_lvm_system_dir (void)
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static int
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set_filter (char *const *filters)
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{
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CLEANUP_AUG_CLOSE augeas *aug = NULL;
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int r;
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int count;
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const char *filter_types[] = { "filter", "global_filter", NULL };
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CLEANUP_FREE char *conf = NULL;
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FILE *fp;
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size_t i, j;
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/* Small optimization: do not load the files at init time,
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* but do that only after having applied the transformation.
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*/
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const int flags = AUG_NO_ERR_CLOSE | AUG_NO_LOAD;
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aug = aug_init (lvm_system_dir, "/usr/share/guestfs/", flags);
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if (!aug) {
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reply_with_error ("augeas initialization failed");
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if (asprintf (&conf, "%s/lvm/lvm.conf", lvm_system_dir) == -1) {
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reply_with_perror ("asprintf");
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return -1;
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}
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fp = fopen (conf, "we");
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if (fp == NULL) {
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reply_with_perror ("open: %s", conf);
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return -1;
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}
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if (aug_error (aug) != AUG_NOERROR) {
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AUGEAS_ERROR ("aug_init");
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return -1;
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}
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fprintf (fp, "devices {\n");
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for (j = 0; filter_types[j] != NULL; ++j) {
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fprintf (fp, " %s = [\n", filter_types[j]);
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fprintf (fp, " ");
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r = aug_transform (aug, "guestfs_lvm_conf", "/lvm/lvm.conf",
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0 /* = included */);
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if (r == -1) {
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AUGEAS_ERROR ("aug_transform");
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return -1;
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}
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if (aug_load (aug) == -1) {
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AUGEAS_ERROR ("aug_load");
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return -1;
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}
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/* Remove all the old filters ... */
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r = aug_rm (aug, "/files/lvm/lvm.conf/devices/dict/filter/list/*");
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if (r == -1) {
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AUGEAS_ERROR ("aug_rm/filter");
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return -1;
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}
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r = aug_rm (aug, "/files/lvm/lvm.conf/devices/dict/global_filter/list/*");
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if (r == -1) {
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AUGEAS_ERROR ("aug_rm/global_filter");
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return -1;
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}
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/* ... and add the new ones. */
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for (count = 0; filters[count] != NULL; ++count) {
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char buf[128];
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snprintf (buf, sizeof buf,
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"/files/lvm/lvm.conf/devices/dict/filter/list/%d/str",
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count + 1);
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if (aug_set (aug, buf, filters[count]) == -1) {
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AUGEAS_ERROR ("aug_set/filter: %d: %s", count, filters[count]);
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return -1;
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for (i = 0; filters[i] != NULL; ++i) {
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if (i > 0)
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fprintf (fp, ",\n ");
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fprintf (fp, "\"%s\"", filters[i]);
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}
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snprintf (buf, sizeof buf,
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"/files/lvm/lvm.conf/devices/dict/global_filter/list/%d/str",
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count + 1);
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fprintf (fp, "\n");
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fprintf (fp, " ]\n");
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}
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fprintf (fp, "}\n");
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if (aug_set (aug, buf, filters[count]) == -1) {
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AUGEAS_ERROR ("aug_set/global_filter: %d: %s", count, filters[count]);
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return -1;
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}
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}
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fclose (fp);
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/* Safety check for the written filter nodes. */
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r = aug_match (aug, "/files/lvm/lvm.conf/devices/dict/filter/list/*/str",
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NULL);
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if (r == -1) {
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AUGEAS_ERROR ("aug_match/filter");
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return -1;
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}
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if (r != count) {
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reply_with_error ("filters# vs matches mismatch: %d vs %d", count, r);
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return -1;
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}
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r = aug_match (aug, "/files/lvm/lvm.conf/devices/dict/global_filter/list/*/str",
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NULL);
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if (r == -1) {
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AUGEAS_ERROR ("aug_match/global_filter");
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return -1;
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}
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if (r != count) {
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reply_with_error ("global_filter# vs matches mismatch: %d vs %d", count, r);
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return -1;
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}
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if (aug_save (aug) == -1) {
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AUGEAS_ERROR ("aug_save");
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return -1;
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}
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debug_lvm_config ();
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return 0;
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}
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@@ -267,6 +191,16 @@ rescan (void)
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return 0;
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}
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/* Show what lvm thinks is the current config. Useful for debugging. */
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static void
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debug_lvm_config (void)
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{
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if (verbose) {
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fprintf (stderr, "lvm config:\n");
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ignore_value (system ("lvm config"));
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}
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}
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/* Construct the new, specific filter strings. We can assume that
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* the 'devices' array does not contain any regexp metachars,
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* because it's already been checked by the stub code.
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