libmount: improve optlist

* cache already generated mount strings

* add mnt_optlist_merge_opts() to de-duplicate mount options

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
index 65d4a37c6d219c4385027605a9bc39bff117f92a..669a3360c656bd369e1a2b4b7ac70136f2597377 100644 (file)
--- a/libmount/src/mountP.h
+++ b/libmount/src/mountP.h
@@ -385,9 +385,10 @@ struct libmnt_context
        unsigned long   user_mountflags;        /* MNT_MS_* (loop=, user=, ...) */
        unsigned long   orig_mountflags;        /* original flags (see mnt_context_merge_mflags()) */
 
-       struct libmnt_cache     *cache; /* paths cache */
-       struct libmnt_lock      *lock;  /* utab lock */
-       struct libmnt_update    *update;/* utab update */
+       struct libmnt_cache     *cache;         /* paths cache */
+       struct libmnt_lock      *lock;          /* utab lock */
+       struct libmnt_update    *update;        /* utab update */
+       struct libmnt_optlist   *optlist;       /* parsed mount options */
 
        const char      *mountinfo_path; /* usualy /proc/self/moutinfo */
 
@@ -507,12 +508,12 @@ extern int mnt_optlist_insert_flags(struct libmnt_optlist *ls, unsigned long fla
                         const struct libmnt_optmap *after_map);
 extern int mnt_optlist_get_flags(struct libmnt_optlist *ls, unsigned long *flags,
                           const struct libmnt_optmap *map);
-extern int mnt_optlist_get_optstr(struct libmnt_optlist *ol, char **optstr,
+extern int mnt_optlist_get_optstr(struct libmnt_optlist *ol, const char **optstr,
                         const struct libmnt_optmap *map);
 extern int mnt_optlist_get_propagation(struct libmnt_optlist *ls);
 extern int mnt_optlist_is_propagation_only(struct libmnt_optlist *ls);
 extern int mnt_opt_has_value(struct libmnt_opt *opt);
-extern int mnt_optlist_set_merged(struct libmnt_optlist *ls, int enable);
+extern int mnt_optlist_merge_opts(struct libmnt_optlist *ls);
 
 
 /* fs.c */
@@ -577,6 +578,8 @@ extern int mnt_context_is_veritydev(struct libmnt_context *cxt)
 extern int mnt_context_setup_veritydev(struct libmnt_context *cxt);
 extern int mnt_context_deferred_delete_veritydev(struct libmnt_context *cxt);
 
+extern struct libmnt_optlist *mnt_context_get_optlist(struct libmnt_context *cxt);
+
 /* tab_update.c */
 extern int mnt_update_set_filename(struct libmnt_update *upd, const char *filename);
 extern int mnt_update_already_done(struct libmnt_update *upd,

diff --git a/libmount/src/optlist.c b/libmount/src/optlist.c
index 85c9c6911543307024a2dc6b7583a6cda4b6204d..ce2712e3237469bd9880b5d3b9bc000e8fc59529 100644 (file)
--- a/libmount/src/optlist.c
+++ b/libmount/src/optlist.c
@@ -45,6 +45,9 @@ struct libmnt_optlist {
        const struct libmnt_optmap      *maps[MNT_OPTLIST_MAXMAPS];
        size_t nmaps;
 
+       char *cached_str[MNT_OPTLIST_MAXMAPS];
+       char *cached_all;
+
        unsigned long           propagation;    /* propagation MS_ flags */
        struct list_head        opts;           /* parsed options */
 
@@ -77,6 +80,8 @@ void mnt_ref_optlist(struct libmnt_optlist *ls)
 
 void mnt_unref_optlist(struct libmnt_optlist *ls)
 {
+       size_t i;
+
        if (!ls)
                return;
 
@@ -90,6 +95,10 @@ void mnt_unref_optlist(struct libmnt_optlist *ls)
                mnt_optlist_remove_opt(ls, opt);
        }
 
+       for (i = 0; i < ls->nmaps; i++)
+               free(ls->cached_str[i]);
+
+       free(ls->cached_all);
        free(ls);
 }
 
@@ -112,13 +121,37 @@ int mnt_optlist_register_map(struct libmnt_optlist *ls, const struct libmnt_optm
        return 0;
 }
 
+static size_t optlist_get_mapidx(struct libmnt_optlist *ls, const struct libmnt_optmap *map)
+{
+       size_t i;
+
+       assert(ls);
+       assert(map);
 
-int mnt_optlist_set_merged(struct libmnt_optlist *ls, int enable)
+       for (i = 0; i < ls->nmaps; i++)
+               if (map == ls->maps[i])
+                       return i;
+
+       return (size_t) -1;
+}
+
+static void optlist_cleanup_cached(struct libmnt_optlist *ls, const struct libmnt_optmap *map)
 {
-       if (!ls)
-               return -EINVAL;
-       ls->merged = enable ? 1 : 0;
-       return 0;
+       if (list_empty(&ls->opts))
+               return;
+
+       free(ls->cached_all);
+       ls->cached_all = NULL;
+
+       if (map) {
+               size_t idx = optlist_get_mapidx(ls, map);
+
+               if (idx == (size_t) -1)
+                       return;
+
+               free(ls->cached_str[idx]);
+               ls->cached_str[idx] = NULL;
+       }
 }
 
 int mnt_optlist_remove_opt(struct libmnt_optlist *ls, struct libmnt_opt *opt)
@@ -131,6 +164,8 @@ int mnt_optlist_remove_opt(struct libmnt_optlist *ls, struct libmnt_opt *opt)
            && opt->map == ls->linux_map && opt->ent->id & MS_PROPAGATION)
                ls->propagation &= ~opt->ent->id;
 
+       optlist_cleanup_cached(ls, opt->map);
+
        list_del_init(&opt->opts);
        free(opt->value);
        free(opt->name);
@@ -201,6 +236,57 @@ struct libmnt_opt *mnt_optlist_get_named(struct libmnt_optlist *ls,
        return NULL;
 }
 
+static int is_equal_opts(struct libmnt_opt *a, struct libmnt_opt *b)
+{
+       if (a->map != b->map)
+               return 0;
+       if (a->ent && b->ent && a->ent != b->ent)
+               return 0;
+       if ((a->value && !b->value) || (!a->value && b->value))
+               return 0;
+       if (strcmp(a->name, b->name) != 0)
+               return 0;
+       if (a->value && b->value && strcmp(a->value, b->value) != 0)
+               return 0;
+
+       return 1;
+}
+
+int mnt_optlist_merge_opts(struct libmnt_optlist *ls)
+{
+       struct libmnt_iter itr;
+       struct libmnt_opt *opt;
+
+       if (!ls)
+               return -EINVAL;
+
+       DBG(OPTLIST, ul_debugobj(ls, "merging"));
+       ls->merged = 1;
+
+       /* deduplicate, keep last instance of the option only */
+       mnt_reset_iter(&itr, MNT_ITER_BACKWARD);
+
+       while (mnt_optlist_next_opt(ls, &itr, &opt) == 0) {
+               struct libmnt_iter xtr;
+               struct libmnt_opt *x;
+
+               mnt_reset_iter(&xtr, MNT_ITER_FORWARD);
+               while (mnt_optlist_next_opt(ls, &xtr, &x) == 0) {
+                       if (opt == x)
+                               break;  /* no another instance */
+
+                       if (is_equal_opts(opt, x)) {
+                               /* me sure @itr does not point to removed item */
+                               if (itr.p == &x->opts)
+                                       itr.p = x->opts.prev;
+                               mnt_optlist_remove_opt(ls, x);
+                       }
+               }
+       }
+
+       return 0;
+}
+
 static struct libmnt_opt *optlist_new_opt(struct libmnt_optlist *ls,
                        const char *name, size_t namesz,
                        const char *value, size_t valsz,
@@ -275,6 +361,8 @@ static int optlist_add_optstr(struct libmnt_optlist *ls, const char *optstr,
                opt->src = MNT_OPTSRC_STRING;
        }
 
+       optlist_cleanup_cached(ls, map);
+
        return 0;
 }
 
@@ -291,6 +379,9 @@ int mnt_optlist_set_optstr(struct libmnt_optlist *ls, const char *optstr,
 {
        struct list_head *p, *next;
 
+       if (!ls)
+               return -EINVAL;
+
        DBG(OPTLIST, ul_debugobj(ls, "set %s", optstr));
 
        /* remove all already set options */
@@ -311,6 +402,9 @@ int mnt_optlist_set_optstr(struct libmnt_optlist *ls, const char *optstr,
 int mnt_optlist_append_optstr(struct libmnt_optlist *ls, const char *optstr,
                        const struct libmnt_optmap *map)
 {
+       if (!ls)
+               return -EINVAL;
+
        DBG(OPTLIST, ul_debugobj(ls, "append %s", optstr));
        return optlist_add_optstr(ls, optstr, map, NULL);
 }
@@ -318,6 +412,9 @@ int mnt_optlist_append_optstr(struct libmnt_optlist *ls, const char *optstr,
 int mnt_optlist_prepend_optstr(struct libmnt_optlist *ls, const char *optstr,
                        const struct libmnt_optmap *map)
 {
+       if (!ls)
+               return -EINVAL;
+
        DBG(OPTLIST, ul_debugobj(ls, "prepend %s", optstr));
        return optlist_add_optstr(ls, optstr, map, &ls->opts);
 }
@@ -365,6 +462,8 @@ static int optlist_add_flags(struct libmnt_optlist *ls, unsigned long flags,
                opt->src = MNT_OPTSRC_FLAG;
        }
 
+       optlist_cleanup_cached(ls, map);
+
        return 0;
 }
 
@@ -450,16 +549,32 @@ int mnt_optlist_get_flags(struct libmnt_optlist *ls, unsigned long *flags,
        return 0;
 }
 
-int mnt_optlist_get_optstr(struct libmnt_optlist *ls, char **optstr,
+int mnt_optlist_get_optstr(struct libmnt_optlist *ls, const char **optstr,
                        const struct libmnt_optmap *map)
 {
        struct libmnt_iter itr;
        struct libmnt_opt *opt;
        struct ul_buffer buf = UL_INIT_BUFFER;
+       size_t idx = 0;
+       char *str = NULL;
 
        if (!ls || !optstr)
                return -EINVAL;
 
+       *optstr = NULL;
+
+       if (map) {
+               idx = optlist_get_mapidx(ls, map);
+               if (idx == (size_t) -1)
+                       return -EINVAL;
+               if (ls->cached_str[idx])
+                       str = ls->cached_str[idx];
+       } else if (ls->cached_all)
+               str = ls->cached_all;
+
+       if (str)
+               goto done;
+
        mnt_reset_iter(&itr, MNT_ITER_FORWARD);
 
        while (mnt_optlist_next_opt(ls, &itr, &opt) == 0) {
@@ -469,7 +584,6 @@ int mnt_optlist_get_optstr(struct libmnt_optlist *ls, char **optstr,
                        continue;
                if (!opt->name)
                        continue;
-
                rc = mnt_buffer_append_option(&buf,
                                        opt->name, strlen(opt->name),
                                        opt->value,
@@ -480,8 +594,17 @@ int mnt_optlist_get_optstr(struct libmnt_optlist *ls, char **optstr,
                }
        }
 
-       *optstr = ul_buffer_get_data(&buf, NULL, NULL);
-       DBG(OPTLIST, ul_debugobj(ls, "return optstr %s", *optstr));
+       str = ul_buffer_get_data(&buf, NULL, NULL);
+       if (map)
+               ls->cached_str[idx] = str;
+       else
+               ls->cached_all = str;
+
+done:
+       if (optstr)
+               *optstr = str;
+
+       DBG(OPTLIST, ul_debugobj(ls, "return optstr %s", str));
        return 0;
 }
 
@@ -648,17 +771,19 @@ static int test_set_flg(struct libmnt_test *ts, int argc, char *argv[])
 static int test_get_str(struct libmnt_test *ts, int argc, char *argv[])
 {
        struct libmnt_optlist *ol;
-       char *str = NULL;
+       const char *str = NULL;
        int rc;
 
        if (argc < 2)
                return -EINVAL;
        rc = mk_optlist(&ol, argv[1]);
-       if (!rc)
+       if (!rc) {
+               mnt_optlist_merge_opts(ol);
                rc = mnt_optlist_get_optstr(ol, &str, get_map(argv[2]));
+       }
        if (!rc)
                printf("'%s'\n", str);
-       free(str);
+
        mnt_unref_optlist(ol);
        return rc;
 }