#include <linux/delayacct.h>
#include <linux/cgroupstats.h>
#include <linux/hash.h>
+#include <linux/namei.h>
#include <asm/atomic.h>
/* Hierarchy-specific flags */
unsigned long flags;
- /* The path to use for release notifications. No locking
- * between setting and use - so if userspace updates this
- * while child cgroups exist, you could miss a
- * notification. We ensure that it's always a valid
- * NUL-terminated string */
+ /* The path to use for release notifications. */
char release_agent_path[PATH_MAX];
};
return NULL;
}
+static void free_cg_links(struct list_head *tmp)
+{
+ struct cg_cgroup_link *link;
+ struct cg_cgroup_link *saved_link;
+
+ list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) {
+ list_del(&link->cgrp_link_list);
+ kfree(link);
+ }
+}
+
/*
* allocate_cg_links() allocates "count" cg_cgroup_link structures
* and chains them on tmp through their cgrp_link_list fields. Returns 0 on
static int allocate_cg_links(int count, struct list_head *tmp)
{
struct cg_cgroup_link *link;
- struct cg_cgroup_link *saved_link;
int i;
INIT_LIST_HEAD(tmp);
for (i = 0; i < count; i++) {
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link) {
- list_for_each_entry_safe(link, saved_link, tmp,
- cgrp_link_list) {
- list_del(&link->cgrp_link_list);
- kfree(link);
- }
+ free_cg_links(tmp);
return -ENOMEM;
}
list_add(&link->cgrp_link_list, tmp);
return 0;
}
-static void free_cg_links(struct list_head *tmp)
-{
- struct cg_cgroup_link *link;
- struct cg_cgroup_link *saved_link;
-
- list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) {
- list_del(&link->cgrp_link_list);
- kfree(link);
- }
-}
-
/*
* find_css_set() takes an existing cgroup group and a
* cgroup object, and returns a css_set object that's
* knows that the cgroup won't be removed, as cgroup_rmdir()
* needs that mutex.
*
- * The cgroup_common_file_write handler for operations that modify
- * the cgroup hierarchy holds cgroup_mutex across the entire operation,
- * single threading all such cgroup modifications across the system.
- *
* The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't
* (usually) take cgroup_mutex. These are the two most performance
* critical pieces of code here. The exception occurs on cgroup_exit(),
struct super_block *sb;
struct cgroupfs_root *root;
struct list_head tmp_cg_links;
- INIT_LIST_HEAD(&tmp_cg_links);
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
}
/*
- * Attach task with pid 'pid' to cgroup 'cgrp'. Call with
- * cgroup_mutex, may take task_lock of task
+ * Attach task with pid 'pid' to cgroup 'cgrp'. Call with cgroup_mutex
+ * held. May take task_lock of task
*/
-static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf)
+static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
- pid_t pid;
struct task_struct *tsk;
int ret;
- if (sscanf(pidbuf, "%d", &pid) != 1)
- return -EIO;
-
if (pid) {
rcu_read_lock();
tsk = find_task_by_vpid(pid);
return ret;
}
+static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid)
+{
+ int ret;
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ ret = attach_task_by_pid(cgrp, pid);
+ cgroup_unlock();
+ return ret;
+}
+
/* The various types of files and directories in a cgroup file system */
enum cgroup_filetype {
FILE_ROOT,
FILE_RELEASE_AGENT,
};
+/**
+ * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive.
+ * @cgrp: the cgroup to be checked for liveness
+ *
+ * On success, returns true; the lock should be later released with
+ * cgroup_unlock(). On failure returns false with no lock held.
+ */
+bool cgroup_lock_live_group(struct cgroup *cgrp)
+{
+ mutex_lock(&cgroup_mutex);
+ if (cgroup_is_removed(cgrp)) {
+ mutex_unlock(&cgroup_mutex);
+ return false;
+ }
+ return true;
+}
+
+static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buffer)
+{
+ BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ strcpy(cgrp->root->release_agent_path, buffer);
+ cgroup_unlock();
+ return 0;
+}
+
+static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *seq)
+{
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ seq_puts(seq, cgrp->root->release_agent_path);
+ seq_putc(seq, '\n');
+ cgroup_unlock();
+ return 0;
+}
+
+/* A buffer size big enough for numbers or short strings */
+#define CGROUP_LOCAL_BUFFER_SIZE 64
+
static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft,
struct file *file,
const char __user *userbuf,
size_t nbytes, loff_t *unused_ppos)
{
- char buffer[64];
+ char buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
char *end;
const char __user *userbuf,
size_t nbytes, loff_t *unused_ppos)
{
- char local_buffer[64];
+ char local_buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
size_t max_bytes = cft->max_write_len;
char *buffer = local_buffer;
if (buffer == NULL)
return -ENOMEM;
}
- if (nbytes && copy_from_user(buffer, userbuf, nbytes))
- return -EFAULT;
+ if (nbytes && copy_from_user(buffer, userbuf, nbytes)) {
+ retval = -EFAULT;
+ goto out;
+ }
buffer[nbytes] = 0; /* nul-terminate */
strstrip(buffer);
retval = cft->write_string(cgrp, cft, buffer);
if (!retval)
retval = nbytes;
+out:
if (buffer != local_buffer)
kfree(buffer);
return retval;
}
-static ssize_t cgroup_common_file_write(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
-{
- enum cgroup_filetype type = cft->private;
- char *buffer;
- int retval = 0;
-
- if (nbytes >= PATH_MAX)
- return -E2BIG;
-
- /* +1 for nul-terminator */
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (buffer == NULL)
- return -ENOMEM;
-
- if (copy_from_user(buffer, userbuf, nbytes)) {
- retval = -EFAULT;
- goto out1;
- }
- buffer[nbytes] = 0; /* nul-terminate */
- strstrip(buffer); /* strip -just- trailing whitespace */
-
- mutex_lock(&cgroup_mutex);
-
- /*
- * This was already checked for in cgroup_file_write(), but
- * check again now we're holding cgroup_mutex.
- */
- if (cgroup_is_removed(cgrp)) {
- retval = -ENODEV;
- goto out2;
- }
-
- switch (type) {
- case FILE_TASKLIST:
- retval = attach_task_by_pid(cgrp, buffer);
- break;
- case FILE_NOTIFY_ON_RELEASE:
- clear_bit(CGRP_RELEASABLE, &cgrp->flags);
- if (simple_strtoul(buffer, NULL, 10) != 0)
- set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
- else
- clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
- break;
- case FILE_RELEASE_AGENT:
- BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
- strcpy(cgrp->root->release_agent_path, buffer);
- break;
- default:
- retval = -EINVAL;
- goto out2;
- }
-
- if (retval == 0)
- retval = nbytes;
-out2:
- mutex_unlock(&cgroup_mutex);
-out1:
- kfree(buffer);
- return retval;
-}
-
static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
size_t nbytes, loff_t *ppos)
{
char __user *buf, size_t nbytes,
loff_t *ppos)
{
- char tmp[64];
+ char tmp[CGROUP_LOCAL_BUFFER_SIZE];
u64 val = cft->read_u64(cgrp, cft);
int len = sprintf(tmp, "%llu\n", (unsigned long long) val);
char __user *buf, size_t nbytes,
loff_t *ppos)
{
- char tmp[64];
+ char tmp[CGROUP_LOCAL_BUFFER_SIZE];
s64 val = cft->read_s64(cgrp, cft);
int len = sprintf(tmp, "%lld\n", (long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
-static ssize_t cgroup_common_file_read(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file,
- char __user *buf,
- size_t nbytes, loff_t *ppos)
-{
- enum cgroup_filetype type = cft->private;
- char *page;
- ssize_t retval = 0;
- char *s;
-
- if (!(page = (char *)__get_free_page(GFP_KERNEL)))
- return -ENOMEM;
-
- s = page;
-
- switch (type) {
- case FILE_RELEASE_AGENT:
- {
- struct cgroupfs_root *root;
- size_t n;
- mutex_lock(&cgroup_mutex);
- root = cgrp->root;
- n = strnlen(root->release_agent_path,
- sizeof(root->release_agent_path));
- n = min(n, (size_t) PAGE_SIZE);
- strncpy(s, root->release_agent_path, n);
- mutex_unlock(&cgroup_mutex);
- s += n;
- break;
- }
- default:
- retval = -EINVAL;
- goto out;
- }
- *s++ = '\n';
-
- retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
-out:
- free_page((unsigned long)page);
- return retval;
-}
-
static ssize_t cgroup_file_read(struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
{
return cft->read_seq_string(state->cgroup, cft, m);
}
-int cgroup_seqfile_release(struct inode *inode, struct file *file)
+static int cgroup_seqfile_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
kfree(seq->private);
static struct file_operations cgroup_seqfile_operations = {
.read = seq_read,
+ .write = cgroup_file_write,
.llseek = seq_lseek,
.release = cgroup_seqfile_release,
};
return notify_on_release(cgrp);
}
+static int cgroup_write_notify_on_release(struct cgroup *cgrp,
+ struct cftype *cft,
+ u64 val)
+{
+ clear_bit(CGRP_RELEASABLE, &cgrp->flags);
+ if (val)
+ set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ else
+ clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ return 0;
+}
+
/*
* for the common functions, 'private' gives the type of file
*/
.name = "tasks",
.open = cgroup_tasks_open,
.read = cgroup_tasks_read,
- .write = cgroup_common_file_write,
+ .write_u64 = cgroup_tasks_write,
.release = cgroup_tasks_release,
.private = FILE_TASKLIST,
},
{
.name = "notify_on_release",
.read_u64 = cgroup_read_notify_on_release,
- .write = cgroup_common_file_write,
+ .write_u64 = cgroup_write_notify_on_release,
.private = FILE_NOTIFY_ON_RELEASE,
},
};
static struct cftype cft_release_agent = {
.name = "release_agent",
- .read = cgroup_common_file_read,
- .write = cgroup_common_file_write,
+ .read_seq_string = cgroup_release_agent_show,
+ .write_string = cgroup_release_agent_write,
+ .max_write_len = PATH_MAX,
.private = FILE_RELEASE_AGENT,
};
return cgroup_create(c_parent, dentry, mode | S_IFDIR);
}
-static inline int cgroup_has_css_refs(struct cgroup *cgrp)
+static int cgroup_has_css_refs(struct cgroup *cgrp)
{
/* Check the reference count on each subsystem. Since we
* already established that there are no tasks in the
* cgroup_clone - clone the cgroup the given subsystem is attached to
* @tsk: the task to be moved
* @subsys: the given subsystem
+ * @nodename: the name for the new cgroup
*
* Duplicate the current cgroup in the hierarchy that the given
* subsystem is attached to, and move this task into the new
* child.
*/
-int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys)
+int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
+ char *nodename)
{
struct dentry *dentry;
int ret = 0;
- char nodename[MAX_CGROUP_TYPE_NAMELEN];
struct cgroup *parent, *child;
struct inode *inode;
struct css_set *cg;
cg = tsk->cgroups;
parent = task_cgroup(tsk, subsys->subsys_id);
- snprintf(nodename, MAX_CGROUP_TYPE_NAMELEN, "%d", tsk->pid);
-
/* Pin the hierarchy */
atomic_inc(&parent->root->sb->s_active);
while (!list_empty(&release_list)) {
char *argv[3], *envp[3];
int i;
- char *pathbuf;
+ char *pathbuf = NULL, *agentbuf = NULL;
struct cgroup *cgrp = list_entry(release_list.next,
struct cgroup,
release_list);
list_del_init(&cgrp->release_list);
spin_unlock(&release_list_lock);
pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!pathbuf) {
- spin_lock(&release_list_lock);
- continue;
- }
-
- if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0) {
- kfree(pathbuf);
- spin_lock(&release_list_lock);
- continue;
- }
+ if (!pathbuf)
+ goto continue_free;
+ if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0)
+ goto continue_free;
+ agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
+ if (!agentbuf)
+ goto continue_free;
i = 0;
- argv[i++] = cgrp->root->release_agent_path;
- argv[i++] = (char *)pathbuf;
+ argv[i++] = agentbuf;
+ argv[i++] = pathbuf;
argv[i] = NULL;
i = 0;
* be a slow process */
mutex_unlock(&cgroup_mutex);
call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
- kfree(pathbuf);
mutex_lock(&cgroup_mutex);
+ continue_free:
+ kfree(pathbuf);
+ kfree(agentbuf);
spin_lock(&release_list_lock);
}
spin_unlock(&release_list_lock);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff