#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/fs.h>
+#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/security.h>
}
EXPORT_SYMBOL(free_task);
-void __put_task_struct(struct task_struct *tsk)
+void __put_task_struct_cb(struct rcu_head *rhp)
{
+ struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
WARN_ON(atomic_read(&tsk->usage));
WARN_ON(tsk == current);
}
}
+/*
+ * Allocate a new mm structure and copy contents from the
+ * mm structure of the passed in task structure.
+ */
+static struct mm_struct *dup_mm(struct task_struct *tsk)
+{
+ struct mm_struct *mm, *oldmm = current->mm;
+ int err;
+
+ if (!oldmm)
+ return NULL;
+
+ mm = allocate_mm();
+ if (!mm)
+ goto fail_nomem;
+
+ memcpy(mm, oldmm, sizeof(*mm));
+
+ if (!mm_init(mm))
+ goto fail_nomem;
+
+ if (init_new_context(tsk, mm))
+ goto fail_nocontext;
+
+ err = dup_mmap(mm, oldmm);
+ if (err)
+ goto free_pt;
+
+ mm->hiwater_rss = get_mm_rss(mm);
+ mm->hiwater_vm = mm->total_vm;
+
+ return mm;
+
+free_pt:
+ mmput(mm);
+
+fail_nomem:
+ return NULL;
+
+fail_nocontext:
+ /*
+ * If init_new_context() failed, we cannot use mmput() to free the mm
+ * because it calls destroy_context()
+ */
+ mm_free_pgd(mm);
+ free_mm(mm);
+ return NULL;
+}
+
static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
{
struct mm_struct * mm, *oldmm;
}
retval = -ENOMEM;
- mm = allocate_mm();
+ mm = dup_mm(tsk);
if (!mm)
goto fail_nomem;
- /* Copy the current MM stuff.. */
- memcpy(mm, oldmm, sizeof(*mm));
- if (!mm_init(mm))
- goto fail_nomem;
-
- if (init_new_context(tsk,mm))
- goto fail_nocontext;
-
- retval = dup_mmap(mm, oldmm);
- if (retval)
- goto free_pt;
-
- mm->hiwater_rss = get_mm_rss(mm);
- mm->hiwater_vm = mm->total_vm;
-
good_mm:
tsk->mm = mm;
tsk->active_mm = mm;
return 0;
-free_pt:
- mmput(mm);
fail_nomem:
return retval;
-
-fail_nocontext:
- /*
- * If init_new_context() failed, we cannot use mmput() to free the mm
- * because it calls destroy_context()
- */
- mm_free_pgd(mm);
- free_mm(mm);
- return retval;
}
static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
return newf;
}
-static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
+/*
+ * Allocate a new files structure and copy contents from the
+ * passed in files structure.
+ */
+static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
{
- struct files_struct *oldf, *newf;
+ struct files_struct *newf;
struct file **old_fds, **new_fds;
- int open_files, size, i, error = 0, expand;
+ int open_files, size, i, expand;
struct fdtable *old_fdt, *new_fdt;
- /*
- * A background process may not have any files ...
- */
- oldf = current->files;
- if (!oldf)
- goto out;
-
- if (clone_flags & CLONE_FILES) {
- atomic_inc(&oldf->count);
- goto out;
- }
-
- /*
- * Note: we may be using current for both targets (See exec.c)
- * This works because we cache current->files (old) as oldf. Don't
- * break this.
- */
- tsk->files = NULL;
- error = -ENOMEM;
newf = alloc_files();
if (!newf)
goto out;
if (expand) {
spin_unlock(&oldf->file_lock);
spin_lock(&newf->file_lock);
- error = expand_files(newf, open_files-1);
+ *errorp = expand_files(newf, open_files-1);
spin_unlock(&newf->file_lock);
- if (error < 0)
+ if (*errorp < 0)
goto out_release;
new_fdt = files_fdtable(newf);
/*
memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
}
- tsk->files = newf;
- error = 0;
out:
- return error;
+ return newf;
out_release:
free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset);
goto out;
}
+static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
+{
+ struct files_struct *oldf, *newf;
+ int error = 0;
+
+ /*
+ * A background process may not have any files ...
+ */
+ oldf = current->files;
+ if (!oldf)
+ goto out;
+
+ if (clone_flags & CLONE_FILES) {
+ atomic_inc(&oldf->count);
+ goto out;
+ }
+
+ /*
+ * Note: we may be using current for both targets (See exec.c)
+ * This works because we cache current->files (old) as oldf. Don't
+ * break this.
+ */
+ tsk->files = NULL;
+ error = -ENOMEM;
+ newf = dup_fd(oldf, &error);
+ if (!newf)
+ goto out;
+
+ tsk->files = newf;
+ error = 0;
+out:
+ return error;
+}
+
/*
* Helper to unshare the files of the current task.
* We don't want to expose copy_files internals to
init_sigpending(&sig->shared_pending);
INIT_LIST_HEAD(&sig->posix_timers);
- hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC);
+ hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL);
sig->it_real_incr.tv64 = 0;
sig->real_timer.function = it_real_fn;
sig->real_timer.data = tsk;
p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
/*
+ * sigaltstack should be cleared when sharing the same VM
+ */
+ if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
+ p->sas_ss_sp = p->sas_ss_size = 0;
+
+ /*
* Syscall tracing should be turned off in the child regardless
* of CLONE_PTRACE.
*/
p->real_parent = current;
p->parent = p->real_parent;
+ spin_lock(¤t->sighand->siglock);
if (clone_flags & CLONE_THREAD) {
- spin_lock(¤t->sighand->siglock);
/*
* Important: if an exit-all has been started then
* do not create this new thread - the whole thread
*/
p->it_prof_expires = jiffies_to_cputime(1);
}
-
- spin_unlock(¤t->sighand->siglock);
}
/*
if (unlikely(p->ptrace & PT_PTRACED))
__ptrace_link(p, current->parent);
- attach_pid(p, PIDTYPE_PID, p->pid);
- attach_pid(p, PIDTYPE_TGID, p->tgid);
if (thread_group_leader(p)) {
p->signal->tty = current->signal->tty;
p->signal->pgrp = process_group(current);
if (p->pid)
__get_cpu_var(process_counts)++;
}
+ attach_pid(p, PIDTYPE_TGID, p->tgid);
+ attach_pid(p, PIDTYPE_PID, p->pid);
nr_threads++;
total_forks++;
+ spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
proc_fork_connector(p);
return p;
return pid;
}
+#ifndef ARCH_MIN_MMSTRUCT_ALIGN
+#define ARCH_MIN_MMSTRUCT_ALIGN 0
+#endif
+
void __init proc_caches_init(void)
{
sighand_cachep = kmem_cache_create("sighand_cache",
sizeof(struct vm_area_struct), 0,
SLAB_PANIC, NULL, NULL);
mm_cachep = kmem_cache_create("mm_struct",
- sizeof(struct mm_struct), 0,
+ sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
}
+
+
+/*
+ * Check constraints on flags passed to the unshare system call and
+ * force unsharing of additional process context as appropriate.
+ */
+static inline void check_unshare_flags(unsigned long *flags_ptr)
+{
+ /*
+ * If unsharing a thread from a thread group, must also
+ * unshare vm.
+ */
+ if (*flags_ptr & CLONE_THREAD)
+ *flags_ptr |= CLONE_VM;
+
+ /*
+ * If unsharing vm, must also unshare signal handlers.
+ */
+ if (*flags_ptr & CLONE_VM)
+ *flags_ptr |= CLONE_SIGHAND;
+
+ /*
+ * If unsharing signal handlers and the task was created
+ * using CLONE_THREAD, then must unshare the thread
+ */
+ if ((*flags_ptr & CLONE_SIGHAND) &&
+ (atomic_read(¤t->signal->count) > 1))
+ *flags_ptr |= CLONE_THREAD;
+
+ /*
+ * If unsharing namespace, must also unshare filesystem information.
+ */
+ if (*flags_ptr & CLONE_NEWNS)
+ *flags_ptr |= CLONE_FS;
+}
+
+/*
+ * Unsharing of tasks created with CLONE_THREAD is not supported yet
+ */
+static int unshare_thread(unsigned long unshare_flags)
+{
+ if (unshare_flags & CLONE_THREAD)
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * Unshare the filesystem structure if it is being shared
+ */
+static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
+{
+ struct fs_struct *fs = current->fs;
+
+ if ((unshare_flags & CLONE_FS) &&
+ (fs && atomic_read(&fs->count) > 1)) {
+ *new_fsp = __copy_fs_struct(current->fs);
+ if (!*new_fsp)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/*
+ * Unshare the namespace structure if it is being shared
+ */
+static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs)
+{
+ struct namespace *ns = current->namespace;
+
+ if ((unshare_flags & CLONE_NEWNS) &&
+ (ns && atomic_read(&ns->count) > 1)) {
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs);
+ if (!*new_nsp)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/*
+ * Unsharing of sighand for tasks created with CLONE_SIGHAND is not
+ * supported yet
+ */
+static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
+{
+ struct sighand_struct *sigh = current->sighand;
+
+ if ((unshare_flags & CLONE_SIGHAND) &&
+ (sigh && atomic_read(&sigh->count) > 1))
+ return -EINVAL;
+ else
+ return 0;
+}
+
+/*
+ * Unshare vm if it is being shared
+ */
+static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
+{
+ struct mm_struct *mm = current->mm;
+
+ if ((unshare_flags & CLONE_VM) &&
+ (mm && atomic_read(&mm->mm_users) > 1)) {
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Unshare file descriptor table if it is being shared
+ */
+static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
+{
+ struct files_struct *fd = current->files;
+ int error = 0;
+
+ if ((unshare_flags & CLONE_FILES) &&
+ (fd && atomic_read(&fd->count) > 1)) {
+ *new_fdp = dup_fd(fd, &error);
+ if (!*new_fdp)
+ return error;
+ }
+
+ return 0;
+}
+
+/*
+ * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not
+ * supported yet
+ */
+static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp)
+{
+ if (unshare_flags & CLONE_SYSVSEM)
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * unshare allows a process to 'unshare' part of the process
+ * context which was originally shared using clone. copy_*
+ * functions used by do_fork() cannot be used here directly
+ * because they modify an inactive task_struct that is being
+ * constructed. Here we are modifying the current, active,
+ * task_struct.
+ */
+asmlinkage long sys_unshare(unsigned long unshare_flags)
+{
+ int err = 0;
+ struct fs_struct *fs, *new_fs = NULL;
+ struct namespace *ns, *new_ns = NULL;
+ struct sighand_struct *sigh, *new_sigh = NULL;
+ struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
+ struct files_struct *fd, *new_fd = NULL;
+ struct sem_undo_list *new_ulist = NULL;
+
+ check_unshare_flags(&unshare_flags);
+
+ if ((err = unshare_thread(unshare_flags)))
+ goto bad_unshare_out;
+ if ((err = unshare_fs(unshare_flags, &new_fs)))
+ goto bad_unshare_cleanup_thread;
+ if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs)))
+ goto bad_unshare_cleanup_fs;
+ if ((err = unshare_sighand(unshare_flags, &new_sigh)))
+ goto bad_unshare_cleanup_ns;
+ if ((err = unshare_vm(unshare_flags, &new_mm)))
+ goto bad_unshare_cleanup_sigh;
+ if ((err = unshare_fd(unshare_flags, &new_fd)))
+ goto bad_unshare_cleanup_vm;
+ if ((err = unshare_semundo(unshare_flags, &new_ulist)))
+ goto bad_unshare_cleanup_fd;
+
+ if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) {
+
+ task_lock(current);
+
+ if (new_fs) {
+ fs = current->fs;
+ current->fs = new_fs;
+ new_fs = fs;
+ }
+
+ if (new_ns) {
+ ns = current->namespace;
+ current->namespace = new_ns;
+ new_ns = ns;
+ }
+
+ if (new_sigh) {
+ sigh = current->sighand;
+ rcu_assign_pointer(current->sighand, new_sigh);
+ new_sigh = sigh;
+ }
+
+ if (new_mm) {
+ mm = current->mm;
+ active_mm = current->active_mm;
+ current->mm = new_mm;
+ current->active_mm = new_mm;
+ activate_mm(active_mm, new_mm);
+ new_mm = mm;
+ }
+
+ if (new_fd) {
+ fd = current->files;
+ current->files = new_fd;
+ new_fd = fd;
+ }
+
+ task_unlock(current);
+ }
+
+bad_unshare_cleanup_fd:
+ if (new_fd)
+ put_files_struct(new_fd);
+
+bad_unshare_cleanup_vm:
+ if (new_mm)
+ mmput(new_mm);
+
+bad_unshare_cleanup_sigh:
+ if (new_sigh)
+ if (atomic_dec_and_test(&new_sigh->count))
+ kmem_cache_free(sighand_cachep, new_sigh);
+
+bad_unshare_cleanup_ns:
+ if (new_ns)
+ put_namespace(new_ns);
+
+bad_unshare_cleanup_fs:
+ if (new_fs)
+ put_fs_struct(new_fs);
+
+bad_unshare_cleanup_thread:
+bad_unshare_out:
+ return err;
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff