From b460cbc581a53cc088ceba80608021dd49c63c43 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Thu, 18 Oct 2007 23:39:52 -0700 Subject: pid namespaces: define is_global_init() and is_container_init() is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn Signed-off-by: Sukadev Bhattiprolu Acked-by: Pavel Emelianov Cc: Eric W. Biederman Cc: Cedric Le Goater Cc: Dave Hansen Cc: Herbert Poetzel Cc: Kirill Korotaev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/capability.c | 3 ++- kernel/exit.c | 2 +- kernel/kexec.c | 2 +- kernel/pid.c | 5 +++++ kernel/signal.c | 2 +- kernel/sysctl.c | 2 +- 6 files changed, 11 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index cbc5fd60c0f3..f02ad47320b9 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -12,6 +12,7 @@ #include #include #include +#include #include /* @@ -129,7 +130,7 @@ static inline int cap_set_all(kernel_cap_t *effective, int found = 0; do_each_thread(g, target) { - if (target == current || is_init(target)) + if (target == current || is_container_init(target->group_leader)) continue; found = 1; if (security_capset_check(target, effective, inheritable, diff --git a/kernel/exit.c b/kernel/exit.c index d1eddc753fe3..d22aefabb129 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -221,7 +221,7 @@ static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignor do_each_pid_task(pgrp, PIDTYPE_PGID, p) { if (p == ignored_task || p->exit_state - || is_init(p->real_parent)) + || is_global_init(p->real_parent)) continue; if (task_pgrp(p->real_parent) != pgrp && task_session(p->real_parent) == task_session(p)) { diff --git a/kernel/kexec.c b/kernel/kexec.c index e9f1b4ea504d..fbffdb457cce 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -51,7 +51,7 @@ struct resource crashk_res = { int kexec_should_crash(struct task_struct *p) { - if (in_interrupt() || !p->pid || is_init(p) || panic_on_oops) + if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) return 1; return 0; } diff --git a/kernel/pid.c b/kernel/pid.c index 78c0dbffde65..bb0785109d39 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -70,6 +70,11 @@ struct pid_namespace init_pid_ns = { .child_reaper = &init_task }; +int is_global_init(struct task_struct *tsk) +{ + return tsk == init_pid_ns.child_reaper; +} + /* * Note: disable interrupts while the pidmap_lock is held as an * interrupt might come in and do read_lock(&tasklist_lock). diff --git a/kernel/signal.c b/kernel/signal.c index 0a6d3726cb80..8214ffad54bc 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -256,7 +256,7 @@ flush_signal_handlers(struct task_struct *t, int force_default) int unhandled_signal(struct task_struct *tsk, int sig) { - if (is_init(tsk)) + if (is_global_init(tsk)) return 1; if (tsk->ptrace & PT_PTRACED) return 0; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 067554bda8b7..44868e4df1d3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1888,7 +1888,7 @@ int proc_dointvec_bset(struct ctl_table *table, int write, struct file *filp, return -EPERM; } - op = is_init(current) ? OP_SET : OP_AND; + op = is_global_init(current) ? OP_SET : OP_AND; return do_proc_dointvec(table,write,filp,buffer,lenp,ppos, do_proc_dointvec_bset_conv,&op); } -- cgit v1.2.3