#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/idr.h>
+#include <linux/pidfs.h>
#include <net/sock.h>
#include <uapi/linux/pidfd.h>
int pid_max = PID_MAX_DEFAULT;
-#define RESERVED_PIDS 300
-
int pid_max_min = RESERVED_PIDS + 1;
int pid_max_max = PID_MAX_LIMIT;
+/*
+ * Pseudo filesystems start inode numbering after one. We use Reserved
+ * PIDs as a natural offset.
+ */
+static u64 pidfs_ino = RESERVED_PIDS;
/*
* PID-map pages start out as NULL, they get allocated upon
#ifdef CONFIG_PID_NS
.ns.ops = &pidns_operations,
#endif
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
+ .memfd_noexec_scope = MEMFD_NOEXEC_SCOPE_EXEC,
+#endif
};
EXPORT_SYMBOL_GPL(init_pid_ns);
spin_lock_irq(&pidmap_lock);
if (!(ns->pid_allocated & PIDNS_ADDING))
goto out_unlock;
+ pid->stashed = NULL;
+ pid->ino = ++pidfs_ino;
for ( ; upid >= pid->numbers; --upid) {
/* Make the PID visible to find_pid_ns. */
idr_replace(&upid->ns->idr, pid, upid->nr);
hlist_del_rcu(&task->pid_links[type]);
*pid_ptr = new;
+ if (type == PIDTYPE_PID) {
+ WARN_ON_ONCE(pid_has_task(pid, PIDTYPE_PID));
+ wake_up_all(&pid->wait_pidfd);
+ }
+
for (tmp = PIDTYPE_MAX; --tmp >= 0; )
if (pid_has_task(pid, tmp))
return;
void transfer_pid(struct task_struct *old, struct task_struct *new,
enum pid_type type)
{
- if (type == PIDTYPE_PID)
- new->thread_pid = old->thread_pid;
+ WARN_ON_ONCE(type == PIDTYPE_PID);
hlist_replace_rcu(&old->pid_links[type], &new->pid_links[type]);
}
{
return idr_get_next(&ns->idr, &nr);
}
+EXPORT_SYMBOL_GPL(find_ge_pid);
struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags)
{
* Return the task associated with @pidfd. The function takes a reference on
* the returned task. The caller is responsible for releasing that reference.
*
- * Currently, the process identified by @pidfd is always a thread-group leader.
- * This restriction currently exists for all aspects of pidfds including pidfd
- * creation (CLONE_PIDFD cannot be used with CLONE_THREAD) and pidfd polling
- * (only supports thread group leaders).
- *
* Return: On success, the task_struct associated with the pidfd.
* On error, a negative errno number will be returned.
*/
* Return: On success, a cloexec pidfd is returned.
* On error, a negative errno number will be returned.
*/
-int pidfd_create(struct pid *pid, unsigned int flags)
+static int pidfd_create(struct pid *pid, unsigned int flags)
{
- int fd;
+ int pidfd;
+ struct file *pidfd_file;
- if (!pid || !pid_has_task(pid, PIDTYPE_TGID))
- return -EINVAL;
-
- if (flags & ~(O_NONBLOCK | O_RDWR | O_CLOEXEC))
- return -EINVAL;
-
- fd = anon_inode_getfd("[pidfd]", &pidfd_fops, get_pid(pid),
- flags | O_RDWR | O_CLOEXEC);
- if (fd < 0)
- put_pid(pid);
+ pidfd = pidfd_prepare(pid, flags, &pidfd_file);
+ if (pidfd < 0)
+ return pidfd;
- return fd;
+ fd_install(pidfd, pidfd_file);
+ return pidfd;
}
/**
- * pidfd_open() - Open new pid file descriptor.
+ * sys_pidfd_open() - Open new pid file descriptor.
*
* @pid: pid for which to retrieve a pidfd
* @flags: flags to pass
*
* This creates a new pid file descriptor with the O_CLOEXEC flag set for
- * the process identified by @pid. Currently, the process identified by
- * @pid must be a thread-group leader. This restriction currently exists
- * for all aspects of pidfds including pidfd creation (CLONE_PIDFD cannot
- * be used with CLONE_THREAD) and pidfd polling (only supports thread group
- * leaders).
+ * the task identified by @pid. Without PIDFD_THREAD flag the target task
+ * must be a thread-group leader.
*
* Return: On success, a cloexec pidfd is returned.
* On error, a negative errno number will be returned.
int fd;
struct pid *p;
- if (flags & ~PIDFD_NONBLOCK)
+ if (flags & ~(PIDFD_NONBLOCK | PIDFD_THREAD))
return -EINVAL;
if (pid <= 0)
idr_init(&init_pid_ns.idr);
- init_pid_ns.pid_cachep = KMEM_CACHE(pid,
- SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
+ init_pid_ns.pid_cachep = kmem_cache_create("pid",
+ struct_size_t(struct pid, numbers, 1),
+ __alignof__(struct pid),
+ SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,
+ NULL);
}
static struct file *__pidfd_fget(struct task_struct *task, int fd)
up_read(&task->signal->exec_update_lock);
- return file ?: ERR_PTR(-EBADF);
+ if (!file) {
+ /*
+ * It is possible that the target thread is exiting; it can be
+ * either:
+ * 1. before exit_signals(), which gives a real fd
+ * 2. before exit_files() takes the task_lock() gives a real fd
+ * 3. after exit_files() releases task_lock(), ->files is NULL;
+ * this has PF_EXITING, since it was set in exit_signals(),
+ * __pidfd_fget() returns EBADF.
+ * In case 3 we get EBADF, but that really means ESRCH, since
+ * the task is currently exiting and has freed its files
+ * struct, so we fix it up.
+ */
+ if (task->flags & PF_EXITING)
+ file = ERR_PTR(-ESRCH);
+ else
+ file = ERR_PTR(-EBADF);
+ }
+
+ return file;
}
static int pidfd_getfd(struct pid *pid, int fd)
if (IS_ERR(file))
return PTR_ERR(file);
- ret = receive_fd(file, O_CLOEXEC);
+ ret = receive_fd(file, NULL, O_CLOEXEC);
fput(file);
return ret;
projects / linux-2.6-microblaze.git / blobdiff