Add a helper module for simple regular files

* procfs_file.h: New file, declares procfs_file_make_node.
* procfs_file.c: New file, implements procfs_file_make_node.
* main.c: Use them.
* Makefile: Add the procfs_file module.

3 files changed, 67 insertions, 11 deletions

diff --git a/main.c b/main.c
index cafd0c9a..457cf6a7 100644
--- a/main.c
+++ b/main.c
@@ -3,14 +3,7 @@
 #include <argp.h>
 #include <hurd/netfs.h>
 #include "procfs.h"
-
-static error_t get_contents (void *hook, void **contents, size_t *contents_len)
-{
-  static const char hello[] = "Hello, World!\n";
-  *contents = (void *) hello;
-  *contents_len = sizeof hello - 1;
-  return 0;
-}
+#include "procfs_file.h"
 
 static error_t get_entries (void *hook, void **contents, size_t *contents_len)
 {
@@ -22,12 +15,10 @@ static error_t get_entries (void *hook, void **contents, size_t *contents_len)
 
 static error_t lookup (void *hook, const char *name, struct node **np)
 {
-  static const struct procfs_node_ops ops = { .get_contents = get_contents };
-
   if (strcmp (name, "hello"))
     return ENOENT;
 
-  *np = procfs_make_node (&ops, NULL);
+  *np = procfs_file_make_node ("Hello, World!\n", -1, NULL);
   if (! *np)
     return ENOMEM;
 
diff --git a/procfs_file.c b/procfs_file.c
new file mode 100644
index 00000000..62419ee5
--- /dev/null
+++ b/procfs_file.c
@@ -0,0 +1,59 @@
+#include <hurd/hurd_types.h>
+#include <stdlib.h>
+#include <string.h>
+#include "procfs.h"
+#include "procfs_file.h"
+
+struct procfs_file
+{
+  void *contents;
+  size_t len;
+  void (*cleanup)(void *contents);
+};
+
+error_t
+procfs_file_getcontents (void *hook, void **contents, size_t *contents_len)
+{
+  struct procfs_file *f = hook;
+
+  *contents = f->contents;
+  *contents_len = f->len;
+  return 0;
+}
+
+void
+procfs_file_cleanup (void *hook)
+{
+  struct procfs_file *f = hook;
+
+  if (f->cleanup)
+    f->cleanup (f->contents);
+
+  free (f);
+}
+
+struct node *
+procfs_file_make_node (void *contents, ssize_t len, void (*cleanup)(void *))
+{
+  static const struct procfs_node_ops ops = {
+    .get_contents = procfs_file_getcontents,
+    .cleanup = procfs_file_cleanup,
+  };
+  struct procfs_file *f;
+  struct node *np;
+
+  f = malloc (sizeof *f);
+  if (! f)
+    return NULL;
+
+  f->contents = contents;
+  f->len = (len >= 0) ? len : strlen (f->contents);
+  f->cleanup = cleanup;
+
+  np = procfs_make_node (&ops, f);
+  if (! np)
+    free (f);
+
+  return np;
+}
+
diff --git a/procfs_file.h b/procfs_file.h
new file mode 100644
index 00000000..b615db93
--- /dev/null
+++ b/procfs_file.h
@@ -0,0 +1,6 @@
+/* Create a new regular file with the given CONTENTS. If LEN is negative,
+   CONTENTS is considered as a string and the file stops at the first
+   nul char.  If CLEANUP is non-NULL, it is passed CONTENTS when the
+   node is destroyed.  */
+struct node *
+procfs_file_make_node (void *contents, ssize_t len, void (*cleanup)(void *));