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-rw-r--r--include/linux/cgroup.h6
-rw-r--r--kernel/cgroup.c15
-rw-r--r--security/device_cgroup.c74
3 files changed, 38 insertions, 57 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index d58a958444ab..095248082b7e 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -226,6 +226,12 @@ struct cftype {
*/
int (*read_map) (struct cgroup *cont, struct cftype *cft,
struct cgroup_map_cb *cb);
+ /*
+ * read_seq_string() is used for outputting a simple sequence
+ * using seqfile.
+ */
+ int (*read_seq_string) (struct cgroup *cont, struct cftype *cft,
+ struct seq_file *m);
ssize_t (*write) (struct cgroup *cgrp, struct cftype *cft,
struct file *file,
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index aeceb8868981..abc433772e5a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1549,11 +1549,14 @@ static int cgroup_seqfile_show(struct seq_file *m, void *arg)
{
struct cgroup_seqfile_state *state = m->private;
struct cftype *cft = state->cft;
- struct cgroup_map_cb cb = {
- .fill = cgroup_map_add,
- .state = m,
- };
- return cft->read_map(state->cgroup, cft, &cb);
+ if (cft->read_map) {
+ struct cgroup_map_cb cb = {
+ .fill = cgroup_map_add,
+ .state = m,
+ };
+ return cft->read_map(state->cgroup, cft, &cb);
+ }
+ return cft->read_seq_string(state->cgroup, cft, m);
}
int cgroup_seqfile_release(struct inode *inode, struct file *file)
@@ -1581,7 +1584,7 @@ static int cgroup_file_open(struct inode *inode, struct file *file)
cft = __d_cft(file->f_dentry);
if (!cft)
return -ENODEV;
- if (cft->read_map) {
+ if (cft->read_map || cft->read_seq_string) {
struct cgroup_seqfile_state *state =
kzalloc(sizeof(*state), GFP_USER);
if (!state)
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 4237b19e8fb3..4ea583689eec 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -9,6 +9,7 @@
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/uaccess.h>
+#include <linux/seq_file.h>
#define ACC_MKNOD 1
#define ACC_READ 2
@@ -201,11 +202,15 @@ static void devcgroup_destroy(struct cgroup_subsys *ss,
#define DEVCG_ALLOW 1
#define DEVCG_DENY 2
+#define DEVCG_LIST 3
+
+#define MAJMINLEN 10
+#define ACCLEN 4
static void set_access(char *acc, short access)
{
int idx = 0;
- memset(acc, 0, 4);
+ memset(acc, 0, ACCLEN);
if (access & ACC_READ)
acc[idx++] = 'r';
if (access & ACC_WRITE)
@@ -225,70 +230,33 @@ static char type_to_char(short type)
return 'X';
}
-static void set_majmin(char *str, int len, unsigned m)
+static void set_majmin(char *str, unsigned m)
{
- memset(str, 0, len);
+ memset(str, 0, MAJMINLEN);
if (m == ~0)
sprintf(str, "*");
else
- snprintf(str, len, "%d", m);
+ snprintf(str, MAJMINLEN, "%d", m);
}
-static char *print_whitelist(struct dev_cgroup *devcgroup, int *len)
+static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
+ struct seq_file *m)
{
- char *buf, *s, acc[4];
+ struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
struct dev_whitelist_item *wh;
- int ret;
- int count = 0;
- char maj[10], min[10];
-
- buf = kmalloc(4096, GFP_KERNEL);
- if (!buf)
- return ERR_PTR(-ENOMEM);
- s = buf;
- *s = '\0';
- *len = 0;
+ char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
spin_lock(&devcgroup->lock);
list_for_each_entry(wh, &devcgroup->whitelist, list) {
set_access(acc, wh->access);
- set_majmin(maj, 10, wh->major);
- set_majmin(min, 10, wh->minor);
- ret = snprintf(s, 4095-(s-buf), "%c %s:%s %s\n",
- type_to_char(wh->type), maj, min, acc);
- if (s+ret >= buf+4095) {
- kfree(buf);
- buf = ERR_PTR(-ENOMEM);
- break;
- }
- s += ret;
- *len += ret;
- count++;
+ set_majmin(maj, wh->major);
+ set_majmin(min, wh->minor);
+ seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
+ maj, min, acc);
}
spin_unlock(&devcgroup->lock);
- return buf;
-}
-
-static ssize_t devcgroup_access_read(struct cgroup *cgroup,
- struct cftype *cft, struct file *file,
- char __user *userbuf, size_t nbytes, loff_t *ppos)
-{
- struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
- int filetype = cft->private;
- char *buffer;
- int uninitialized_var(len);
- int retval;
-
- if (filetype != DEVCG_ALLOW)
- return -EINVAL;
- buffer = print_whitelist(devcgroup, &len);
- if (IS_ERR(buffer))
- return PTR_ERR(buffer);
-
- retval = simple_read_from_buffer(userbuf, nbytes, ppos, buffer, len);
- kfree(buffer);
- return retval;
+ return 0;
}
/*
@@ -501,7 +469,6 @@ out1:
static struct cftype dev_cgroup_files[] = {
{
.name = "allow",
- .read = devcgroup_access_read,
.write = devcgroup_access_write,
.private = DEVCG_ALLOW,
},
@@ -510,6 +477,11 @@ static struct cftype dev_cgroup_files[] = {
.write = devcgroup_access_write,
.private = DEVCG_DENY,
},
+ {
+ .name = "list",
+ .read_seq_string = devcgroup_seq_read,
+ .private = DEVCG_LIST,
+ },
};
static int devcgroup_populate(struct cgroup_subsys *ss,