pid namespaces: allow cloning of new namespace
[deliverable/linux.git] / kernel / fork.c
index 125246fc75a5aa1caf3e666a89a9bf1a2c5bc798..f252784f93308077d483bca888593ec7fad36774 100644 (file)
@@ -29,7 +29,7 @@
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
 #include <linux/cpu.h>
-#include <linux/cpuset.h>
+#include <linux/cgroup.h>
 #include <linux/security.h>
 #include <linux/swap.h>
 #include <linux/syscalls.h>
@@ -268,7 +268,7 @@ static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
                        get_file(file);
                        if (tmp->vm_flags & VM_DENYWRITE)
                                atomic_dec(&inode->i_writecount);
-      
+
                        /* insert tmp into the share list, just after mpnt */
                        spin_lock(&file->f_mapping->i_mmap_lock);
                        tmp->vm_truncate_count = mpnt->vm_truncate_count;
@@ -331,7 +331,7 @@ static inline void mm_free_pgd(struct mm_struct * mm)
 #define mm_free_pgd(mm)
 #endif /* CONFIG_MMU */
 
- __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
 
 #define allocate_mm()  (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
 #define free_mm(mm)    (kmem_cache_free(mm_cachep, (mm)))
@@ -738,8 +738,8 @@ static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
        /* compute the remainder to be cleared */
        size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
 
-       /* This is long word aligned thus could use a optimized version */ 
-       memset(new_fds, 0, size); 
+       /* This is long word aligned thus could use a optimized version */
+       memset(new_fds, 0, size);
 
        if (new_fdt->max_fds > open_files) {
                int left = (new_fdt->max_fds-open_files)/8;
@@ -973,12 +973,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                                        unsigned long stack_start,
                                        struct pt_regs *regs,
                                        unsigned long stack_size,
-                                       int __user *parent_tidptr,
                                        int __user *child_tidptr,
                                        struct pid *pid)
 {
        int retval;
        struct task_struct *p = NULL;
+       int cgroup_callbacks_done = 0;
 
        if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
                return ERR_PTR(-EINVAL);
@@ -1042,12 +1042,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        p->did_exec = 0;
        delayacct_tsk_init(p);  /* Must remain after dup_task_struct() */
        copy_flags(clone_flags, p);
-       p->pid = pid_nr(pid);
-       retval = -EFAULT;
-       if (clone_flags & CLONE_PARENT_SETTID)
-               if (put_user(p->pid, parent_tidptr))
-                       goto bad_fork_cleanup_delays_binfmt;
-
        INIT_LIST_HEAD(&p->children);
        INIT_LIST_HEAD(&p->sibling);
        p->vfork_done = NULL;
@@ -1059,6 +1053,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        p->utime = cputime_zero;
        p->stime = cputime_zero;
        p->gtime = cputime_zero;
+       p->utimescaled = cputime_zero;
+       p->stimescaled = cputime_zero;
 
 #ifdef CONFIG_TASK_XACCT
        p->rchar = 0;           /* I/O counter: bytes read */
@@ -1069,12 +1065,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        task_io_accounting_init(p);
        acct_clear_integrals(p);
 
-       p->it_virt_expires = cputime_zero;
+       p->it_virt_expires = cputime_zero;
        p->it_prof_expires = cputime_zero;
-       p->it_sched_expires = 0;
-       INIT_LIST_HEAD(&p->cpu_timers[0]);
-       INIT_LIST_HEAD(&p->cpu_timers[1]);
-       INIT_LIST_HEAD(&p->cpu_timers[2]);
+       p->it_sched_expires = 0;
+       INIT_LIST_HEAD(&p->cpu_timers[0]);
+       INIT_LIST_HEAD(&p->cpu_timers[1]);
+       INIT_LIST_HEAD(&p->cpu_timers[2]);
 
        p->lock_depth = -1;             /* -1 = no lock */
        do_posix_clock_monotonic_gettime(&p->start_time);
@@ -1085,13 +1081,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #endif
        p->io_context = NULL;
        p->audit_context = NULL;
-       cpuset_fork(p);
+       cgroup_fork(p);
 #ifdef CONFIG_NUMA
        p->mempolicy = mpol_copy(p->mempolicy);
        if (IS_ERR(p->mempolicy)) {
                retval = PTR_ERR(p->mempolicy);
                p->mempolicy = NULL;
-               goto bad_fork_cleanup_cpuset;
+               goto bad_fork_cleanup_cgroup;
        }
        mpol_fix_fork_child_flag(p);
 #endif
@@ -1124,10 +1120,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        p->blocked_on = NULL; /* not blocked yet */
 #endif
 
-       p->tgid = p->pid;
-       if (clone_flags & CLONE_THREAD)
-               p->tgid = current->tgid;
-
        if ((retval = security_task_alloc(p)))
                goto bad_fork_cleanup_policy;
        if ((retval = audit_alloc(p)))
@@ -1153,6 +1145,18 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        if (retval)
                goto bad_fork_cleanup_namespaces;
 
+       if (pid != &init_struct_pid) {
+               retval = -ENOMEM;
+               pid = alloc_pid(task_active_pid_ns(p));
+               if (!pid)
+                       goto bad_fork_cleanup_namespaces;
+       }
+
+       p->pid = pid_nr(pid);
+       p->tgid = p->pid;
+       if (clone_flags & CLONE_THREAD)
+               p->tgid = current->tgid;
+
        p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
        /*
         * Clear TID on mm_release()?
@@ -1202,6 +1206,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        /* Perform scheduler related setup. Assign this task to a CPU. */
        sched_fork(p, clone_flags);
 
+       /* Now that the task is set up, run cgroup callbacks if
+        * necessary. We need to run them before the task is visible
+        * on the tasklist. */
+       cgroup_fork_callbacks(p);
+       cgroup_callbacks_done = 1;
+
        /* Need tasklist lock for parent etc handling! */
        write_lock_irq(&tasklist_lock);
 
@@ -1239,12 +1249,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         * A fatal signal pending means that current will exit, so the new
         * thread can't slip out of an OOM kill (or normal SIGKILL).
         */
-       recalc_sigpending();
+       recalc_sigpending();
        if (signal_pending(current)) {
                spin_unlock(&current->sighand->siglock);
                write_unlock_irq(&tasklist_lock);
                retval = -ERESTARTNOINTR;
-               goto bad_fork_cleanup_namespaces;
+               goto bad_fork_free_pid;
        }
 
        if (clone_flags & CLONE_THREAD) {
@@ -1273,11 +1283,22 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                        __ptrace_link(p, current->parent);
 
                if (thread_group_leader(p)) {
-                       p->signal->tty = current->signal->tty;
-                       p->signal->pgrp = process_group(current);
-                       set_signal_session(p->signal, process_session(current));
-                       attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
-                       attach_pid(p, PIDTYPE_SID, task_session(current));
+                       if (clone_flags & CLONE_NEWPID) {
+                               p->nsproxy->pid_ns->child_reaper = p;
+                               p->signal->tty = NULL;
+                               p->signal->pgrp = p->pid;
+                               set_task_session(p, p->pid);
+                               attach_pid(p, PIDTYPE_PGID, pid);
+                               attach_pid(p, PIDTYPE_SID, pid);
+                       } else {
+                               p->signal->tty = current->signal->tty;
+                               p->signal->pgrp = task_pgrp_nr(current);
+                               set_task_session(p, task_session_nr(current));
+                               attach_pid(p, PIDTYPE_PGID,
+                                               task_pgrp(current));
+                               attach_pid(p, PIDTYPE_SID,
+                                               task_session(current));
+                       }
 
                        list_add_tail_rcu(&p->tasks, &init_task.tasks);
                        __get_cpu_var(process_counts)++;
@@ -1290,8 +1311,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        spin_unlock(&current->sighand->siglock);
        write_unlock_irq(&tasklist_lock);
        proc_fork_connector(p);
+       cgroup_post_fork(p);
        return p;
 
+bad_fork_free_pid:
+       if (pid != &init_struct_pid)
+               free_pid(pid);
 bad_fork_cleanup_namespaces:
        exit_task_namespaces(p);
 bad_fork_cleanup_keys:
@@ -1316,10 +1341,9 @@ bad_fork_cleanup_security:
 bad_fork_cleanup_policy:
 #ifdef CONFIG_NUMA
        mpol_free(p->mempolicy);
-bad_fork_cleanup_cpuset:
+bad_fork_cleanup_cgroup:
 #endif
-       cpuset_exit(p);
-bad_fork_cleanup_delays_binfmt:
+       cgroup_exit(p, cgroup_callbacks_done);
        delayacct_tsk_free(p);
        if (p->binfmt)
                module_put(p->binfmt->module);
@@ -1346,7 +1370,7 @@ struct task_struct * __cpuinit fork_idle(int cpu)
        struct task_struct *task;
        struct pt_regs regs;
 
-       task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL, NULL,
+       task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL,
                                &init_struct_pid);
        if (!IS_ERR(task))
                init_idle(task, cpu);
@@ -1385,19 +1409,16 @@ long do_fork(unsigned long clone_flags,
 {
        struct task_struct *p;
        int trace = 0;
-       struct pid *pid = alloc_pid();
        long nr;
 
-       if (!pid)
-               return -EAGAIN;
-       nr = pid->nr;
        if (unlikely(current->ptrace)) {
                trace = fork_traceflag (clone_flags);
                if (trace)
                        clone_flags |= CLONE_PTRACE;
        }
 
-       p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
+       p = copy_process(clone_flags, stack_start, regs, stack_size,
+                       child_tidptr, NULL);
        /*
         * Do this prior waking up the new thread - the thread pointer
         * might get invalid after that point, if the thread exits quickly.
@@ -1405,6 +1426,17 @@ long do_fork(unsigned long clone_flags,
        if (!IS_ERR(p)) {
                struct completion vfork;
 
+               /*
+                * this is enough to call pid_nr_ns here, but this if
+                * improves optimisation of regular fork()
+                */
+               nr = (clone_flags & CLONE_NEWPID) ?
+                       task_pid_nr_ns(p, current->nsproxy->pid_ns) :
+                               task_pid_vnr(p);
+
+               if (clone_flags & CLONE_PARENT_SETTID)
+                       put_user(nr, parent_tidptr);
+
                if (clone_flags & CLONE_VFORK) {
                        p->vfork_done = &vfork;
                        init_completion(&vfork);
@@ -1438,7 +1470,6 @@ long do_fork(unsigned long clone_flags,
                        }
                }
        } else {
-               free_pid(pid);
                nr = PTR_ERR(p);
        }
        return nr;
@@ -1615,7 +1646,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
        struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
        struct files_struct *fd, *new_fd = NULL;
        struct sem_undo_list *new_ulist = NULL;
-       struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL;
+       struct nsproxy *new_nsproxy = NULL;
 
        check_unshare_flags(&unshare_flags);
 
@@ -1645,14 +1676,13 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
 
        if (new_fs ||  new_mm || new_fd || new_ulist || new_nsproxy) {
 
-               task_lock(current);
-
                if (new_nsproxy) {
-                       old_nsproxy = current->nsproxy;
-                       current->nsproxy = new_nsproxy;
-                       new_nsproxy = old_nsproxy;
+                       switch_task_namespaces(current, new_nsproxy);
+                       new_nsproxy = NULL;
                }
 
+               task_lock(current);
+
                if (new_fs) {
                        fs = current->fs;
                        current->fs = new_fs;
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