Implement simple directories

* procfs_dir.h: New file; declare the procfs_dir_make_node
  function, based on the procfs_dir_entry structure.
* procfs_dir.c: New file; implement simple directories.
* Makefile: Add the procfs_dir module.
* main.c: Use it.

1 files changed, 79 insertions, 0 deletions

diff --git a/procfs_dir.c b/procfs_dir.c
new file mode 100644
index 0000000..4d4faa2
--- /dev/null
+++ b/procfs_dir.c
@@ -0,0 +1,79 @@
+#include <stdlib.h>
+#include <string.h>
+#include "procfs.h"
+#include "procfs_dir.h"
+
+struct procfs_dir_node
+{
+  const struct procfs_dir_entry *entries;
+  void *hook;
+};
+
+static error_t
+procfs_dir_get_contents (void *hook, void **contents, size_t *contents_len)
+{
+  struct procfs_dir_node *dn = hook;
+  const struct procfs_dir_entry *ent;
+  char *pos;
+
+  *contents_len = 0;
+  for (ent = dn->entries; ent->name; ent++)
+    *contents_len += strlen (ent->name) + 1;
+
+  *contents = malloc (*contents_len);
+  if (! *contents)
+    return ENOMEM;
+
+  pos = *contents;
+  for (ent = dn->entries; ent->name; ent++)
+    {
+      strcpy (pos, ent->name);
+      pos += strlen (ent->name) + 1;
+    }
+
+  return 0;
+}
+
+static error_t
+procfs_dir_lookup (void *hook, const char *name, struct node **np)
+{
+  struct procfs_dir_node *dn = hook;
+  const struct procfs_dir_entry *ent;
+
+  for (ent = dn->entries; ent->name && strcmp (name, ent->name); ent++);
+  if (! ent->name)
+    return ENOENT;
+
+  *np = ent->make_node (dn->hook, ent->hook);
+  if (! *np)
+    return ENOMEM;
+
+  return 0;
+}
+
+struct node *
+procfs_dir_make_node (const struct procfs_dir_entry *entries, void *dir_hook)
+{
+  static const struct procfs_node_ops ops = {
+    .get_contents = procfs_dir_get_contents,
+    .lookup = procfs_dir_lookup,
+    .cleanup_contents = free,
+    .cleanup = free,
+  };
+  struct procfs_dir_node *dn;
+  struct node *np;
+
+  dn = malloc (sizeof *dn);
+  if (! dn)
+    return NULL;
+
+  dn->entries = entries;
+  dn->hook = dir_hook;
+
+  np = procfs_make_node (&ops, dn);
+  if (! np)
+    free (dn);
+
+  return np;
+}
+