lsfd: (refactor) use a binary tree as the implementation for mnt_namespaces

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index 046d9e5f5d0b6e91d0ab0e12e9d3f093bebadd32..eb1e5ec8098e6d10fb3aeac855f1c22b6fcf1ac3 100644 (file)
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -99,6 +99,12 @@ struct nodev_table {
 };
 static struct nodev_table nodev_table;
 
+struct mnt_namespace {
+       ino_t id;
+};
+
+static void *mnt_namespaces;   /* for tsearch/tfind */
+
 struct name_manager {
        struct idcache *cache;
        unsigned long next_id;
@@ -435,9 +441,6 @@ static const int default_threads_columns[] = {
 static int columns[ARRAY_SIZE(infos) * 2] = {-1};
 static size_t ncolumns;
 
-static ino_t *mnt_namespaces;
-static size_t nspaces;
-
 struct counter_spec {
        struct list_head specs;
        const char *name;
@@ -621,31 +624,6 @@ static struct libscols_column *add_column_by_id(struct lsfd_control *ctl,
        return cl;
 }
 
-static int has_mnt_ns(ino_t id)
-{
-       size_t i;
-
-       for (i = 0; i < nspaces; i++) {
-               if (mnt_namespaces[i] == id)
-                       return 1;
-       }
-       return 0;
-}
-
-static void add_mnt_ns(ino_t id)
-{
-       size_t nmax = 0;
-
-       if (nspaces)
-               nmax = (nspaces + 16) / 16 * 16;
-       if (nmax <= nspaces + 1) {
-               nmax += 16;
-               mnt_namespaces = xreallocarray(mnt_namespaces,
-                                              nmax, sizeof(ino_t));
-       }
-       mnt_namespaces[nspaces++] = id;
-}
-
 static const struct file_class *stat2class(struct stat *sb)
 {
        dev_t dev;
@@ -1084,6 +1062,53 @@ static void collect_namespace_files_bottomhalf(struct path_cxt *pc, struct proc
                               false);
 }
 
+static struct mnt_namespace *new_mnt_ns(ino_t id)
+{
+       struct mnt_namespace *mnt_ns = xmalloc(sizeof(*mnt_ns));
+
+       mnt_ns->id = id;
+
+       return mnt_ns;
+}
+
+static void free_mnt_ns(void *mnt_ns)
+{
+       free(mnt_ns);
+}
+
+static int compare_mnt_ns(const void *a, const void *b)
+{
+       ino_t A = (((struct mnt_namespace *)a)->id);
+       ino_t B = (((struct mnt_namespace *)b)->id);
+
+       if (A < B)
+               return -1;
+       else if (A == B)
+               return 0;
+       else
+               return 1;
+}
+
+static struct mnt_namespace *find_mnt_ns(ino_t id)
+{
+       struct mnt_namespace key = { .id = id };
+
+       struct mnt_namespace **mnt_ns = tfind(&key, &mnt_namespaces, compare_mnt_ns);
+       if (mnt_ns)
+               return *mnt_ns;
+       return NULL;
+}
+
+static struct mnt_namespace *add_mnt_ns(ino_t id)
+{
+
+       struct mnt_namespace *mnt_ns = new_mnt_ns(id);
+       if (tsearch(mnt_ns, &mnt_namespaces, compare_mnt_ns) == NULL)
+               errx(EXIT_FAILURE, _("failed to allocate memory"));
+
+       return mnt_ns;
+}
+
 static struct nodev *new_nodev(unsigned long minor, const char *filesystem)
 {
        struct nodev *nodev = xcalloc(1, sizeof(*nodev));
@@ -1124,7 +1149,7 @@ static void finalize_nodevs(void)
        for (i = 0; i < NODEV_TABLE_SIZE; i++)
                list_free(&nodev_table.tables[i], struct nodev, nodevs, free_nodev);
 
-       free(mnt_namespaces);
+       tdestroy(mnt_namespaces, free_mnt_ns);
 }
 
 const char *get_nodev_filesystem(unsigned long minor)
@@ -1768,7 +1793,7 @@ static void read_process(struct lsfd_control *ctl, struct path_cxt *pc,
                collect_namespace_files_tophalf(pc, proc);
 
        /* 2/3. read /proc/$pid/mountinfo */
-       if (proc->ns_mnt == 0 || !has_mnt_ns(proc->ns_mnt)) {
+       if (proc->ns_mnt == 0 || !find_mnt_ns(proc->ns_mnt)) {
                FILE *mnt = ul_path_fopen(pc, "r", "mountinfo");
                if (mnt) {
                        read_mountinfo(mnt);