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authorTavian Barnes <tavianator@tavianator.com>2019-08-29 23:45:45 -0400
committerTavian Barnes <tavianator@tavianator.com>2019-08-29 23:45:45 -0400
commit41ac289ca572cf0ed5ecfcc1c73ae59eef461a9e (patch)
tree1354f9064ef2951f8d4eb6daa6a807d1d7eb276b /mtab.c
parent7716a6ef1a60d4597e06cc4d412c3483b29877bc (diff)
downloadbfs-41ac289ca572cf0ed5ecfcc1c73ae59eef461a9e.tar.xz
mtab: Lazy-load the device IDs from the mount table
Fixes #50.
Diffstat (limited to 'mtab.c')
-rw-r--r--mtab.c93
1 files changed, 66 insertions, 27 deletions
diff --git a/mtab.c b/mtab.c
index a06508b..57ea402 100644
--- a/mtab.c
+++ b/mtab.c
@@ -15,6 +15,7 @@
****************************************************************************/
#include "mtab.h"
+#include "darray.h"
#include "trie.h"
#include "util.h"
#include <errno.h>
@@ -49,42 +50,56 @@
# include <sys/mnttab.h>
#endif
+/**
+ * A mount point in the table.
+ */
+struct bfs_mtab_entry {
+ /** The path to the mount point. */
+ char *path;
+ /** The filesystem type. */
+ char *type;
+};
+
struct bfs_mtab {
- /** A map from device ID to file system type. */
- struct trie types;
- /** The names of all the mount points. */
+ /** The list of mount points. */
+ struct bfs_mtab_entry *entries;
+ /** The basenames of every mount point. */
struct trie names;
+
+ /** A map from device ID to fstype (populated lazily). */
+ struct trie types;
+ /** Whether the types map has been populated. */
+ bool types_filled;
};
/**
* Add an entry to the mount table.
*/
static int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *type) {
- if (!trie_insert_str(&mtab->names, xbasename(path))) {
- return -1;
- }
+ struct bfs_mtab_entry entry = {
+ .path = strdup(path),
+ .type = strdup(type),
+ };
- struct bfs_stat sb;
- if (bfs_stat(AT_FDCWD, path, BFS_STAT_NOFOLLOW | BFS_STAT_NOSYNC, &sb) != 0) {
- return 0;
+ if (!entry.path || !entry.type) {
+ goto fail_entry;
}
- struct trie_leaf *leaf = trie_insert_mem(&mtab->types, &sb.dev, sizeof(sb.dev));
- if (!leaf) {
- return -1;
+ if (DARRAY_PUSH(&mtab->entries, &entry) != 0) {
+ goto fail_entry;
}
- if (leaf->value) {
- return 0;
+ if (!trie_insert_str(&mtab->names, xbasename(path))) {
+ goto fail;
}
- leaf->value = strdup(type);
- if (leaf->value) {
- return 0;
- } else {
- trie_remove(&mtab->types, leaf);
- return -1;
- }
+ return 0;
+
+fail_entry:
+ free(entry.type);
+ free(entry.path);
+fail:
+ return -1;
}
struct bfs_mtab *parse_bfs_mtab() {
@@ -93,8 +108,10 @@ struct bfs_mtab *parse_bfs_mtab() {
return NULL;
}
- trie_init(&mtab->types);
+ mtab->entries = NULL;
trie_init(&mtab->names);
+ trie_init(&mtab->types);
+ mtab->types_filled = false;
int error = 0;
@@ -171,7 +188,29 @@ fail:
return NULL;
}
+static void bfs_mtab_fill_types(struct bfs_mtab *mtab) {
+ for (size_t i = 0; i < darray_length(mtab->entries); ++i) {
+ struct bfs_mtab_entry *entry = mtab->entries + i;
+
+ struct bfs_stat sb;
+ if (bfs_stat(AT_FDCWD, entry->path, BFS_STAT_NOFOLLOW | BFS_STAT_NOSYNC, &sb) != 0) {
+ continue;
+ }
+
+ struct trie_leaf *leaf = trie_insert_mem(&mtab->types, &sb.dev, sizeof(sb.dev));
+ if (leaf) {
+ leaf->value = entry->type;
+ }
+ }
+
+ mtab->types_filled = true;
+}
+
const char *bfs_fstype(const struct bfs_mtab *mtab, const struct bfs_stat *statbuf) {
+ if (!mtab->types_filled) {
+ bfs_mtab_fill_types((struct bfs_mtab *)mtab);
+ }
+
const struct trie_leaf *leaf = trie_find_mem(&mtab->types, &statbuf->dev, sizeof(statbuf->dev));
if (leaf) {
return leaf->value;
@@ -187,14 +226,14 @@ bool bfs_maybe_mount(const struct bfs_mtab *mtab, const char *path) {
void free_bfs_mtab(struct bfs_mtab *mtab) {
if (mtab) {
+ trie_destroy(&mtab->types);
trie_destroy(&mtab->names);
- struct trie_leaf *leaf;
- while ((leaf = trie_first_leaf(&mtab->types))) {
- free(leaf->value);
- trie_remove(&mtab->types, leaf);
+ for (size_t i = 0; i < darray_length(mtab->entries); ++i) {
+ free(mtab->entries[i].type);
+ free(mtab->entries[i].path);
}
- trie_destroy(&mtab->types);
+ darray_free(mtab->entries);
free(mtab);
}