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. --- appliance/Makefile.am | 4 +- appliance/guestfs_lvm_conf.aug | 74 ----------------- daemon/daemon.h | 2 +- daemon/guestfsd.c | 2 +- daemon/lvm-filter.c | 178 +++++++++++++---------------------------- 5 files changed, 59 insertions(+), 201 deletions(-) diff --git a/appliance/Makefile.am b/appliance/Makefile.am index 05b9d42e9..42896b9a7 100644 --- a/appliance/Makefile.am +++ b/appliance/Makefile.am @@ -32,7 +32,6 @@ include $(top_srcdir)/subdir-rules.mk EXTRA_DIST = \ 99-guestfs-serial.rules \ excludefiles.in \ - guestfs_lvm_conf.aug \ guestfs_shadow.aug \ hostfiles.in \ init \ @@ -87,12 +86,11 @@ packagelist: packagelist.in Makefile cmp -s $@ $@-t || mv $@-t $@ rm -f $@-t -supermin.d/daemon.tar.gz: ../daemon/guestfsd guestfs_lvm_conf.aug guestfs_shadow.aug +supermin.d/daemon.tar.gz: ../daemon/guestfsd guestfs_shadow.aug rm -f $@ $@-t rm -rf tmp-d mkdir -p tmp-d$(DAEMON_SUPERMIN_DIR) tmp-d/etc tmp-d/usr/share/guestfs ln ../daemon/guestfsd tmp-d$(DAEMON_SUPERMIN_DIR)/guestfsd - ln $(srcdir)/guestfs_lvm_conf.aug tmp-d/usr/share/guestfs/guestfs_lvm_conf.aug ln $(srcdir)/guestfs_shadow.aug tmp-d/usr/share/guestfs/guestfs_shadow.aug ( cd tmp-d && tar zcf - * ) > $@-t rm -r tmp-d diff --git a/appliance/guestfs_lvm_conf.aug b/appliance/guestfs_lvm_conf.aug deleted file mode 100644 index ffa5b01f7..000000000 --- a/appliance/guestfs_lvm_conf.aug +++ /dev/null @@ -1,74 +0,0 @@ -(* -Module: LVM - Parses LVM metadata. - -Author: Gabriel de Perthuis <g2p.code+augeas(a)gmail.com&gt; - -About: License - This file is licensed under the LGPL v2+. - -About: Configuration files - This lens applies to files in /etc/lvm/backup and /etc/lvm/archive. - -About: Examples - The <Test_LVM> file contains various examples and tests. -*) - -module Guestfs_LVM_conf = - autoload xfm - - (* See lvm2/libdm/libdm-config.c for tokenisation; - * libdm uses a blacklist but I prefer the safer whitelist approach. *) - (* View: identifier - * The left hand side of a definition *) - let identifier = /[a-zA-Z0-9_-]+/ - - (* strings can contain backslash-escaped dquotes, but I don't know - * how to get the message across to augeas *) - let str = [label "str". Quote.do_dquote (store /([^\"]|\\\\.)*/)] - let int = [label "int". store Rx.relinteger] - (* View: flat_literal - * A literal without structure *) - let flat_literal = int|str - - (* allow multiline and mixed int/str, used for raids and stripes *) - (* View: list - * A list containing flat literals *) - let list = [ - label "list" . counter "list" - . del /\[[ \t\n]*/ "[" - .([seq "list". flat_literal . del /,[ \t\n]*/ ", "]* - . [seq "list". flat_literal . del /[ \t\n]*/ ""])? - . Util.del_str "]"] - - (* View: val - * Any value that appears on the right hand side of an assignment *) - let val = flat_literal | list - - (* View: nondef - * A line that doesn't contain a statement *) - let nondef = - Util.empty - | Util.comment - - (* Build.block couldn't be reused, because of recursion and - * a different philosophy of whitespace handling. *) - (* View: def - * An assignment, or a block containing definitions *) - let rec def = [ - Util.indent . key identifier . ( - del /[ \t]*\{\n/ " {\n" - .[label "dict".(nondef | def)*] - . Util.indent . Util.del_str "}\n" - |Sep.space_equal . val . Util.comment_or_eol)] - - (* View: lns - * The main lens *) - let lns = (nondef | def)* - - let filter = - incl "/etc/lvm/archive/*.vg" - . incl "/etc/lvm/backup/*" - . Util.stdexcl - - let xfm = transform lns filter diff --git a/daemon/daemon.h b/daemon/daemon.h index 0f0d42836..610168ed8 100644 --- a/daemon/daemon.h +++ b/daemon/daemon.h @@ -255,7 +255,7 @@ extern char *get_blkid_tag (const char *device, const char *tag); extern int lv_canonical (const char *device, char **ret); /* lvm-filter.c */ -extern void copy_lvm (void); +extern void clean_lvm_config (void); extern void start_lvmetad (void); /* zero.c */ diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c index 86592e8dc..a209098d4 100644 --- a/daemon/guestfsd.c +++ b/daemon/guestfsd.c @@ -289,7 +289,7 @@ main (int argc, char *argv[]) * daemon/lvm-filter.c). */ if (!test_mode) { - copy_lvm (); + clean_lvm_config (); start_lvmetad (); } diff --git a/daemon/lvm-filter.c b/daemon/lvm-filter.c index deaecfb67..aff3c68ed 100644 --- a/daemon/lvm-filter.c +++ b/daemon/lvm-filter.c @@ -36,67 +36,49 @@ #include "daemon.h" #include "actions.h" -DECLARE_EXTERNAL_COMMANDS ("lvm", "cp", "rm", "lvmetad") +DECLARE_EXTERNAL_COMMANDS ("lvm", "rm", "lvmetad") -/* This runs during daemon start up and creates a complete copy of - * /etc/lvm so that we can modify it as we desire. We set - * LVM_SYSTEM_DIR to point to the copy. Note that the final directory - * layout is: +/* This runs during daemon start up and creates a fresh LVM + * configuration which we can modify as we desire. LVM allows + * configuration to be completely empty (meaning "all defaults"). + * + * The final directory layout is: + * * /tmp/lvmXXXXXX (lvm_system_dir set to this) * /tmp/lvmXXXXXX/lvm ($LVM_SYSTEM_DIR set to this) - * /tmp/lvmXXXXXX/lvm/lvm.conf (configuration file) - * /tmp/lvmXXXXXX/lvm/cache - * etc. + * /tmp/lvmXXXXXX/lvm/lvm.conf (configuration file - initially empty) */ static char lvm_system_dir[] = "/tmp/lvmXXXXXX"; static void rm_lvm_system_dir (void); +static void debug_lvm_config (void); void -copy_lvm (void) +clean_lvm_config (void) { - struct stat statbuf; - char cmd[64], env[64]; - int r; - - /* If /etc/lvm directory doesn't exist (or isn't a directory) assume - * that this system doesn't support LVM and do nothing. - */ - r = stat ("/etc/lvm", &statbuf); - if (r == -1) { - perror ("copy_lvm: stat: /etc/lvm"); - return; - } - if (! S_ISDIR (statbuf.st_mode)) { - fprintf (stderr, "copy_lvm: warning: /etc/lvm is not a directory\n"); - return; - } + char env[64], conf[64]; + FILE *fp; if (mkdtemp (lvm_system_dir) == NULL) error (EXIT_FAILURE, errno, "mkdtemp: %s", lvm_system_dir); - /* Copy the entire directory */ - snprintf (cmd, sizeof cmd, "%s -a /etc/lvm/ %s", "cp", lvm_system_dir); - r = system (cmd); - if (r == -1) { - perror (cmd); - rmdir (lvm_system_dir); - exit (EXIT_FAILURE); - } - - if (WEXITSTATUS (r) != 0) { - fprintf (stderr, "cp command failed with return code %d\n", - WEXITSTATUS (r)); - rmdir (lvm_system_dir); - exit (EXIT_FAILURE); - } - - /* Set environment variable so we use the copy. */ snprintf (env, sizeof env, "%s/lvm", lvm_system_dir); + mkdir (env, 0755); + snprintf (conf, sizeof conf, "%s/lvm/lvm.conf", lvm_system_dir); + fp = fopen (conf, "w"); + if (fp == NULL) { + perror ("clean_lvm_config: cannot create empty lvm.conf"); + exit (EXIT_FAILURE); + } + fclose (fp); + + /* Set environment variable so we use the clean configuration. */ setenv ("LVM_SYSTEM_DIR", env, 1); /* Set a handler to remove the temporary directory at exit. */ atexit (rm_lvm_system_dir); + + debug_lvm_config (); } /* Try to run lvmetad, without failing if it couldn't. */ @@ -127,98 +109,40 @@ rm_lvm_system_dir (void) static int set_filter (char *const *filters) { - CLEANUP_AUG_CLOSE augeas *aug = NULL; - int r; - int count; + const char *filter_types[] = { "filter", "global_filter", NULL }; + CLEANUP_FREE char *conf = NULL; + FILE *fp; + size_t i, j; - /* Small optimization: do not load the files at init time, - * but do that only after having applied the transformation. - */ - const int flags = AUG_NO_ERR_CLOSE | AUG_NO_LOAD; - aug = aug_init (lvm_system_dir, "/usr/share/guestfs/", flags); - if (!aug) { - reply_with_error ("augeas initialization failed"); + if (asprintf (&conf, "%s/lvm/lvm.conf", lvm_system_dir) == -1) { + reply_with_perror ("asprintf"); return -1; } - - if (aug_error (aug) != AUG_NOERROR) { - AUGEAS_ERROR ("aug_init"); - return -1; - } - - r = aug_transform (aug, "guestfs_lvm_conf", "/lvm/lvm.conf", - 0 /* = included */); - if (r == -1) { - AUGEAS_ERROR ("aug_transform"); - return -1; - } - - if (aug_load (aug) == -1) { - AUGEAS_ERROR ("aug_load"); + fp = fopen (conf, "we"); + if (fp == NULL) { + reply_with_perror ("open: %s", conf); return -1; } - /* Remove all the old filters ... */ - r = aug_rm (aug, "/files/lvm/lvm.conf/devices/dict/filter/list/*"); - if (r == -1) { - AUGEAS_ERROR ("aug_rm/filter"); - return -1; - } - r = aug_rm (aug, "/files/lvm/lvm.conf/devices/dict/global_filter/list/*"); - if (r == -1) { - AUGEAS_ERROR ("aug_rm/global_filter"); - return -1; - } - - /* ... and add the new ones. */ - for (count = 0; filters[count] != NULL; ++count) { - char buf[128]; - - snprintf (buf, sizeof buf, - "/files/lvm/lvm.conf/devices/dict/filter/list/%d/str", - count + 1); + fprintf (fp, "devices {\n"); + for (j = 0; filter_types[j] != NULL; ++j) { + fprintf (fp, " %s = [\n", filter_types[j]); + fprintf (fp, " "); - if (aug_set (aug, buf, filters[count]) == -1) { - AUGEAS_ERROR ("aug_set/filter: %d: %s", count, filters[count]); - return -1; + for (i = 0; filters[i] != NULL; ++i) { + if (i > 0) + fprintf (fp, ",\n "); + fprintf (fp, "\"%s\"", filters[i]); } - snprintf (buf, sizeof buf, - "/files/lvm/lvm.conf/devices/dict/global_filter/list/%d/str", - count + 1); - - if (aug_set (aug, buf, filters[count]) == -1) { - AUGEAS_ERROR ("aug_set/global_filter: %d: %s", count, filters[count]); - return -1; - } + fprintf (fp, "\n"); + fprintf (fp, " ]\n"); } + fprintf (fp, "}\n"); - /* Safety check for the written filter nodes. */ - r = aug_match (aug, "/files/lvm/lvm.conf/devices/dict/filter/list/*/str", - NULL); - if (r == -1) { - AUGEAS_ERROR ("aug_match/filter"); - return -1; - } - if (r != count) { - reply_with_error ("filters# vs matches mismatch: %d vs %d", count, r); - return -1; - } - r = aug_match (aug, "/files/lvm/lvm.conf/devices/dict/global_filter/list/*/str", - NULL); - if (r == -1) { - AUGEAS_ERROR ("aug_match/global_filter"); - return -1; - } - if (r != count) { - reply_with_error ("global_filter# vs matches mismatch: %d vs %d", count, r); - return -1; - } + fclose (fp); - if (aug_save (aug) == -1) { - AUGEAS_ERROR ("aug_save"); - return -1; - } + debug_lvm_config (); return 0; } @@ -269,6 +193,16 @@ rescan (void) return 0; } +/* Show what lvm thinks is the current config. Useful for debugging. */ +static void +debug_lvm_config (void) +{ + if (verbose) { + fprintf (stderr, "lvm config:\n"); + ignore_value (system ("lvm config")); + } +} + /* Construct the new, specific filter strings. We can assume that * the 'devices' array does not contain any regexp metachars, * because it's already been checked by the stub code. -- 2.13.2