Merge git://oss.sgi.com:8090/xfs/xfs-2.6
[linux-drm-fsl-dcu.git] / kernel / signal.c
index fb5da6d19f14eef721f28750307c9654f17a8bfa..228fdb5c01d12a0b1b409b1819a95a4c8d223840 100644 (file)
 #include <linux/ptrace.h>
 #include <linux/signal.h>
 #include <linux/capability.h>
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <linux/nsproxy.h>
+
 #include <asm/param.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -33,7 +37,7 @@
  * SLAB caches for signal bits.
  */
 
-static kmem_cache_t *sigqueue_cachep;
+static struct kmem_cache *sigqueue_cachep;
 
 /*
  * In POSIX a signal is sent either to a specific thread (Linux task)
@@ -267,18 +271,25 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
                                         int override_rlimit)
 {
        struct sigqueue *q = NULL;
+       struct user_struct *user;
 
-       atomic_inc(&t->user->sigpending);
+       /*
+        * In order to avoid problems with "switch_user()", we want to make
+        * sure that the compiler doesn't re-load "t->user"
+        */
+       user = t->user;
+       barrier();
+       atomic_inc(&user->sigpending);
        if (override_rlimit ||
-           atomic_read(&t->user->sigpending) <=
+           atomic_read(&user->sigpending) <=
                        t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
                q = kmem_cache_alloc(sigqueue_cachep, flags);
        if (unlikely(q == NULL)) {
-               atomic_dec(&t->user->sigpending);
+               atomic_dec(&user->sigpending);
        } else {
                INIT_LIST_HEAD(&q->list);
                q->flags = 0;
-               q->user = get_uid(t->user);
+               q->user = get_uid(user);
        }
        return(q);
 }
@@ -575,7 +586,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
        error = -EPERM;
        if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
            && ((sig != SIGCONT) ||
-               (current->signal->session != t->signal->session))
+               (process_session(current) != process_session(t)))
            && (current->euid ^ t->suid) && (current->euid ^ t->uid)
            && (current->uid ^ t->suid) && (current->uid ^ t->uid)
            && !capable(CAP_KILL))
@@ -1055,28 +1066,44 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
 }
 
 /*
- * kill_pg_info() sends a signal to a process group: this is what the tty
+ * kill_pgrp_info() sends a signal to a process group: this is what the tty
  * control characters do (^C, ^Z etc)
  */
 
-int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
+int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
 {
        struct task_struct *p = NULL;
        int retval, success;
 
-       if (pgrp <= 0)
-               return -EINVAL;
-
        success = 0;
        retval = -ESRCH;
-       do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
+       do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
                int err = group_send_sig_info(sig, info, p);
                success |= !err;
                retval = err;
-       } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
+       } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
        return success ? 0 : retval;
 }
 
+int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
+{
+       int retval;
+
+       read_lock(&tasklist_lock);
+       retval = __kill_pgrp_info(sig, info, pgrp);
+       read_unlock(&tasklist_lock);
+
+       return retval;
+}
+
+int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
+{
+       if (pgrp <= 0)
+               return -EINVAL;
+
+       return __kill_pgrp_info(sig, info, find_pid(pgrp));
+}
+
 int
 kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
 {
@@ -1089,30 +1116,37 @@ kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
        return retval;
 }
 
-int
-kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
 {
        int error;
-       int acquired_tasklist_lock = 0;
        struct task_struct *p;
 
        rcu_read_lock();
-       if (unlikely(sig_needs_tasklist(sig))) {
+       if (unlikely(sig_needs_tasklist(sig)))
                read_lock(&tasklist_lock);
-               acquired_tasklist_lock = 1;
-       }
-       p = find_task_by_pid(pid);
+
+       p = pid_task(pid, PIDTYPE_PID);
        error = -ESRCH;
        if (p)
                error = group_send_sig_info(sig, info, p);
-       if (unlikely(acquired_tasklist_lock))
+
+       if (unlikely(sig_needs_tasklist(sig)))
                read_unlock(&tasklist_lock);
        rcu_read_unlock();
        return error;
 }
 
-/* like kill_proc_info(), but doesn't use uid/euid of "current" */
-int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
+static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+{
+       int error;
+       rcu_read_lock();
+       error = kill_pid_info(sig, info, find_pid(pid));
+       rcu_read_unlock();
+       return error;
+}
+
+/* like kill_pid_info(), but doesn't use uid/euid of "current" */
+int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
                      uid_t uid, uid_t euid, u32 secid)
 {
        int ret = -EINVAL;
@@ -1122,7 +1156,7 @@ int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
                return ret;
 
        read_lock(&tasklist_lock);
-       p = find_task_by_pid(pid);
+       p = pid_task(pid, PIDTYPE_PID);
        if (!p) {
                ret = -ESRCH;
                goto out_unlock;
@@ -1146,7 +1180,7 @@ out_unlock:
        read_unlock(&tasklist_lock);
        return ret;
 }
-EXPORT_SYMBOL_GPL(kill_proc_info_as_uid);
+EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
 
 /*
  * kill_something_info() interprets pid in interesting ways just like kill(2).
@@ -1264,6 +1298,18 @@ force_sigsegv(int sig, struct task_struct *p)
        return 0;
 }
 
+int kill_pgrp(struct pid *pid, int sig, int priv)
+{
+       return kill_pgrp_info(sig, __si_special(priv), pid);
+}
+EXPORT_SYMBOL(kill_pgrp);
+
+int kill_pid(struct pid *pid, int sig, int priv)
+{
+       return kill_pid_info(sig, __si_special(priv), pid);
+}
+EXPORT_SYMBOL(kill_pid);
+
 int
 kill_pg(pid_t pgrp, int sig, int priv)
 {
@@ -1658,7 +1704,9 @@ finish_stop(int stop_count)
                read_unlock(&tasklist_lock);
        }
 
-       schedule();
+       do {
+               schedule();
+       } while (try_to_freeze());
        /*
         * Now we don't run again until continued.
         */
@@ -1833,8 +1881,12 @@ relock:
                if (sig_kernel_ignore(signr)) /* Default is nothing. */
                        continue;
 
-               /* Init gets no signals it doesn't want.  */
-               if (current == child_reaper)
+               /*
+                * Init of a pid space gets no signals it doesn't want from
+                * within that pid space. It can of course get signals from
+                * its parent pid space.
+                */
+               if (current == child_reaper(current))
                        continue;
 
                if (sig_kernel_stop(signr)) {
@@ -2230,7 +2282,7 @@ static int do_tkill(int tgid, int pid, int sig)
  *  @pid: the PID of the thread
  *  @sig: signal to be sent
  *
- *  This syscall also checks the tgid and returns -ESRCH even if the PID
+ *  This syscall also checks the @tgid and returns -ESRCH even if the PID
  *  exists but it's not belonging to the target process anymore. This
  *  method solves the problem of threads exiting and PIDs getting reused.
  */