This patch adds /proc/ucounts where all non-zero ucounts for a current
userns are shown.
$ cat /proc/ucounts
user: 1000 1
net: 1000 1
mnt: 1000 2
mnt: 0 10
cgroup: 0 1
There are three columns: type, uid, value.
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx>
---
kernel/ucount.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 121 insertions(+)
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 9d20d5d..02a7b7f 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -9,6 +9,8 @@
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/hash.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
#include <linux/user_namespace.h>
#define UCOUNTS_HASHTABLE_BITS 10
@@ -232,4 +234,123 @@ static __init int user_namespace_sysctl_init(void)
}
subsys_initcall(user_namespace_sysctl_init);
+#ifdef CONFIG_PROC_FS
+struct ucounts_iterator {
+ int hash;
+};
+
+static void *ucounts_start(struct seq_file *f, loff_t *pos)
+{
+ struct ucounts_iterator *iter = f->private;
+ struct user_namespace *ns = current_user_ns();
+ int h, i = 0;
+
+ spin_lock(&ucounts_lock);
+ for (h = 0; h < (1 << UCOUNTS_HASHTABLE_BITS); h++) {
+ struct ucounts *ucounts;
+
+ hlist_for_each_entry(ucounts, &ucounts_hashtable[h], node) {
+ if (ucounts->ns != ns)
+ continue;
+ if (i++ < *pos)
+ continue;
+
+ iter->hash = h;
+
+ return ucounts;
+ }
+ }
+
+ return NULL;
+}
+
+static void ucounts_stop(struct seq_file *f, void *v)
+{
+ spin_unlock(&ucounts_lock);
+}
+
+static void *ucounts_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ struct ucounts_iterator *iter = f->private;
+ struct user_namespace *ns = current_user_ns();
+ struct ucounts *ucounts = v;
+ int h;
+
+ ++*pos;
+
+ for (h = iter->hash; h < (1 << UCOUNTS_HASHTABLE_BITS); h++) {
+ struct hlist_node *node;
+
+ if (ucounts == NULL) {
+ node = ucounts_hashtable[h].first;
+ iter->hash = h;
+ } else
+ node = ucounts->node.next;
+
+ ucounts = hlist_entry(node, struct ucounts, node);
+
+ hlist_for_each_entry_from(ucounts, node) {
+ if (ucounts->ns != ns)
+ continue;
+
+ return ucounts;
+ }
+
+ ucounts = NULL;
+ }
+
+ return NULL;
+}
+
+static int ucounts_show(struct seq_file *f, void *v)
+{
+ static const char * const ns_strs[] = {
+ "user", "pid", "uts", "ipc",
+ "net", "mnt", "cgroup", NULL
+ };
+ struct user_namespace *ns = current_user_ns();
+ struct ucounts *ucounts = v;
+ uid_t uid;
+ int i;
+
+ uid = from_kuid_munged(ns, ucounts->uid);
+
+ for (i = 0; ns_strs[i]; i++) {
+ int val = atomic_read(&ucounts->ucount[i]);
+
+ if (val == 0)
+ continue;
+
+ seq_printf(f, "%s:\t%10u\t%10d\n", ns_strs[i], uid, val);
+ }
+ return 0;
+}
+
+static const struct seq_operations ucounts_seq_operations = {
+ .start = ucounts_start,
+ .next = ucounts_next,
+ .stop = ucounts_stop,
+ .show = ucounts_show,
+};
+
+static int ucounts_open(struct inode *inode, struct file *filp)
+{
+ return seq_open_private(filp, &ucounts_seq_operations,
+ sizeof(struct ucounts_iterator));
+}
+
+static const struct file_operations proc_ucounts_operations = {
+ .open = ucounts_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_private,
+};
+
+static int __init proc_ucounts_init(void)
+{
+ proc_create("ucounts", 0, NULL, &proc_ucounts_operations);
+ return 0;
+}
+fs_initcall(proc_ucounts_init);
+#endif /* CONFIG_PROC_FS */
--
2.5.5
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