[RFC][patch 12/21] PID Virtualization: Context for pid_to_vpid conversition functions

From: Hubertus Franke
Date: Thu Dec 15 2005 - 09:42:00 EST

pid_to_vpid conversion require the context task relative to which
the conversion should take place. For instance, the virtual init process
of a container is vpid=1 relative to the tasks of that container,
vpid=-1 from within a different container and vpid=pid in the global context.

By default we assume that the virtual access functions are called
within the context of the task's container itself.
Provide the context for the pid_to_vpid translations
vpids are with respect to a context task.
In this patch we therefore only identify where the context is different
then the default.

Signed-off-by: Hubertus Franke <frankeh@xxxxxxxxxxxxxx>
--

fs/binfmt_elf.c | 4 ++--
fs/fcntl.c | 2 +-
fs/proc/array.c | 18 +++++++++---------
fs/proc/base.c | 4 ++--
include/linux/sched.h | 41 +++++++++++++++++++++++++++++++++++++----
ipc/msg.c | 8 ++++----
ipc/sem.c | 2 +-
ipc/shm.c | 8 ++++----
kernel/exit.c | 4 ++--
kernel/fork.c | 3 ++-
kernel/signal.c | 4 ++--
kernel/sys.c | 7 ++++---
kernel/timer.c | 2 +-
13 files changed, 71 insertions(+), 36 deletions(-)

Index: linux-2.6.15-rc1/fs/proc/base.c
===================================================================
--- linux-2.6.15-rc1.orig/fs/proc/base.c 2005-12-14 15:14:38.000000000 -0500
+++ linux-2.6.15-rc1/fs/proc/base.c 2005-12-14 15:16:46.000000000 -0500
@@ -2102,7 +2102,7 @@ static int get_tgid_list(int index, unsi
p = next_task(&init_task);

for ( ; p != &init_task; p = next_task(p)) {
- int tgid = task_vpid(p);
+ int tgid = task_vpid_ctx(p, current);
if (!pid_alive(p))
continue;
if (--index >= 0)
@@ -2135,7 +2135,7 @@ static int get_tid_list(int index, unsig
* via next_thread().
*/
if (pid_alive(task)) do {
- int tid = task_vpid(task);
+ int tid = task_vpid_ctx(task, current);

if (--index >= 0)
continue;
Index: linux-2.6.15-rc1/fs/proc/array.c
===================================================================
--- linux-2.6.15-rc1.orig/fs/proc/array.c 2005-12-14 15:12:36.000000000 -0500
+++ linux-2.6.15-rc1/fs/proc/array.c 2005-12-14 15:16:46.000000000 -0500
@@ -165,11 +165,11 @@ static inline char * task_state(struct t

read_lock(&tasklist_lock);
if (pid_alive(p))
- ppid = task_vtgid(p->group_leader->real_parent);
+ ppid = task_vtgid_ctx(p->group_leader->real_parent, current);
else
ppid = 0;
if (pid_alive(p) && p->ptrace)
- tpid = task_vppid(p);
+ tpid = task_vppid_ctx(p, current);
else
tpid = 0;
buffer += sprintf(buffer,
@@ -183,8 +183,8 @@ static inline char * task_state(struct t
"Gid:\t%d\t%d\t%d\t%d\n",
get_task_state(p),
(p->sleep_avg/1024)*100/(1020000000/1024),
- task_vtgid(p),
- task_vpid(p),
+ task_vtgid_ctx(p,current),
+ task_vpid_ctx(p,current),
ppid, tpid,
p->uid, p->euid, p->suid, p->fsuid,
p->gid, p->egid, p->sgid, p->fsgid);
@@ -379,11 +379,11 @@ static int do_task_stat(struct task_stru
}
if (task->signal) {
if (task->signal->tty) {
- tty_pgrp = pid_to_vpid(task->signal->tty->pgrp);
+ tty_pgrp = pid_to_vpid_ctx(task->signal->tty->pgrp, current);
tty_nr = new_encode_dev(tty_devnum(task->signal->tty));
}
- pgid = virt_process_group(task);
- sid = pid_to_vpid(task->signal->session);
+ pgid = pid_to_vpid_ctx(process_group(task), current);
+ sid = pid_to_vpid_ctx(task->signal->session, current);
cmin_flt = task->signal->cmin_flt;
cmaj_flt = task->signal->cmaj_flt;
cutime = task->signal->cutime;
@@ -398,7 +398,7 @@ static int do_task_stat(struct task_stru
it_real_value = task->signal->it_real_value;
}
ppid = pid_alive(task) ?
- task_vtgid(task->group_leader->real_parent) : 0;
+ pid_to_vpid_ctx(task_tgid(task->group_leader->real_parent), current) : 0;
read_unlock(&tasklist_lock);

if (!whole || num_threads<2)
@@ -425,7 +425,7 @@ static int do_task_stat(struct task_stru
res = sprintf(buffer,"%d (%s) %c %d %d %d %d %d %lu %lu \
%lu %lu %lu %lu %lu %ld %ld %ld %ld %d %ld %llu %lu %ld %lu %lu %lu %lu %lu \
%lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu\n",
- task_vpid(task),
+ task_vpid_ctx(task,current),
tcomm,
state,
ppid,
Index: linux-2.6.15-rc1/fs/fcntl.c
===================================================================
--- linux-2.6.15-rc1.orig/fs/fcntl.c 2005-12-14 15:16:34.000000000 -0500
+++ linux-2.6.15-rc1/fs/fcntl.c 2005-12-14 15:17:01.000000000 -0500
@@ -317,7 +317,7 @@ static long do_fcntl(int fd, unsigned in
* current syscall conventions, the only way
* to fix this will be in libc.
*/
- err = pgid_to_vpgid(filp->f_owner.pid);
+ err = pgid_to_vpgid_ctx(filp->f_owner.pid, current);
force_successful_syscall_return();
break;
case F_SETOWN:
Index: linux-2.6.15-rc1/ipc/msg.c
===================================================================
--- linux-2.6.15-rc1.orig/ipc/msg.c 2005-12-14 15:12:36.000000000 -0500
+++ linux-2.6.15-rc1/ipc/msg.c 2005-12-14 15:16:46.000000000 -0500
@@ -416,8 +416,8 @@ asmlinkage long sys_msgctl (int msqid, i
tbuf.msg_cbytes = msq->q_cbytes;
tbuf.msg_qnum = msq->q_qnum;
tbuf.msg_qbytes = msq->q_qbytes;
- tbuf.msg_lspid = pid_to_vpid(msq->q_lspid);
- tbuf.msg_lrpid = pid_to_vpid(msq->q_lrpid);
+ tbuf.msg_lspid = pid_to_vpid_ctx(msq->q_lspid, current);
+ tbuf.msg_lrpid = pid_to_vpid_ctx(msq->q_lrpid, current);
msg_unlock(msq);
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
@@ -821,8 +821,8 @@ static int sysvipc_msg_proc_show(struct
msq->q_perm.mode,
msq->q_cbytes,
msq->q_qnum,
- pid_to_vpid(msq->q_lspid),
- pid_to_vpid(msq->q_lrpid),
+ pid_to_vpid_ctx(msq->q_lspid, current),
+ pid_to_vpid_ctx(msq->q_lrpid, current),
msq->q_perm.uid,
msq->q_perm.gid,
msq->q_perm.cuid,
Index: linux-2.6.15-rc1/ipc/shm.c
===================================================================
--- linux-2.6.15-rc1.orig/ipc/shm.c 2005-12-14 15:12:36.000000000 -0500
+++ linux-2.6.15-rc1/ipc/shm.c 2005-12-14 15:16:46.000000000 -0500
@@ -508,8 +508,8 @@ asmlinkage long sys_shmctl (int shmid, i
tbuf.shm_atime = shp->shm_atim;
tbuf.shm_dtime = shp->shm_dtim;
tbuf.shm_ctime = shp->shm_ctim;
- tbuf.shm_cpid = pid_to_vpid(shp->shm_cprid);
- tbuf.shm_lpid = pid_to_vpid(shp->shm_lprid);
+ tbuf.shm_cpid = pid_to_vpid_ctx(shp->shm_cprid, current);
+ tbuf.shm_lpid = pid_to_vpid_ctx(shp->shm_lprid, current);
if (!is_file_hugepages(shp->shm_file))
tbuf.shm_nattch = shp->shm_nattch;
else
@@ -896,8 +896,8 @@ static int sysvipc_shm_proc_show(struct
shp->id,
shp->shm_flags,
shp->shm_segsz,
- pid_to_vpid(shp->shm_cprid),
- pid_to_vpid(shp->shm_lprid),
+ pid_to_vpid_ctx(shp->shm_cprid, current),
+ pid_to_vpid_ctx(shp->shm_lprid, current),
is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
shp->shm_perm.uid,
shp->shm_perm.gid,
Index: linux-2.6.15-rc1/ipc/sem.c
===================================================================
--- linux-2.6.15-rc1.orig/ipc/sem.c 2005-12-14 15:12:27.000000000 -0500
+++ linux-2.6.15-rc1/ipc/sem.c 2005-12-14 15:16:46.000000000 -0500
@@ -721,7 +721,7 @@ static int semctl_main(int semid, int se
err = curr->semval;
goto out_unlock;
case GETPID:
- err = curr->sempid;
+ err = pid_to_vpid_ctx(curr->sempid, current);
goto out_unlock;
case GETNCNT:
err = count_semncnt(sma,semnum);
Index: linux-2.6.15-rc1/kernel/exit.c
===================================================================
--- linux-2.6.15-rc1.orig/kernel/exit.c 2005-12-14 15:14:42.000000000 -0500
+++ linux-2.6.15-rc1/kernel/exit.c 2005-12-14 15:16:46.000000000 -0500
@@ -1143,7 +1143,7 @@ static int wait_task_zombie(task_t *p, i
p->exit_state = EXIT_ZOMBIE;
return retval;
}
- retval = task_vpid(p);
+ retval = task_vpid_ctx(p, current);
if (p->real_parent != p->parent) {
write_lock_irq(&tasklist_lock);
/* Double-check with lock held. */
@@ -1278,7 +1278,7 @@ bail_ref:
if (!retval && infop)
retval = put_user(p->uid, &infop->si_uid);
if (!retval)
- retval = task_vpid(p);
+ retval = task_vpid_ctx(p, current);
put_task_struct(p);

BUG_ON(!retval);
Index: linux-2.6.15-rc1/kernel/fork.c
===================================================================
--- linux-2.6.15-rc1.orig/kernel/fork.c 2005-12-14 15:12:36.000000000 -0500
+++ linux-2.6.15-rc1/kernel/fork.c 2005-12-14 15:16:46.000000000 -0500
@@ -928,9 +928,10 @@ static task_t *copy_process(unsigned lon
p->did_exec = 0;
copy_flags(clone_flags, p);
p->__pid = pid;
+
retval = -EFAULT;
if (clone_flags & CLONE_PARENT_SETTID)
- if (put_user(task_vpid(p), parent_tidptr))
+ if (put_user(task_vpid_ctx(p, current), parent_tidptr))
goto bad_fork_cleanup;

p->proc_dentry = NULL;
Index: linux-2.6.15-rc1/kernel/signal.c
===================================================================
--- linux-2.6.15-rc1.orig/kernel/signal.c 2005-12-14 15:14:38.000000000 -0500
+++ linux-2.6.15-rc1/kernel/signal.c 2005-12-14 15:16:46.000000000 -0500
@@ -1478,7 +1478,7 @@ void do_notify_parent(struct task_struct

info.si_signo = sig;
info.si_errno = 0;
- info.si_pid = task_vpid(tsk);
+ info.si_pid = task_vpid_ctx(tsk, tsk->parent);
info.si_uid = tsk->uid;

/* FIXME: find out whether or not this is supposed to be c*time. */
@@ -1543,7 +1543,7 @@ static void do_notify_parent_cldstop(str

info.si_signo = SIGCHLD;
info.si_errno = 0;
- info.si_pid = task_vpid(tsk);
+ info.si_pid = task_vpid_ctx(tsk, tsk->parent);
info.si_uid = tsk->uid;

/* FIXME: find out whether or not this is supposed to be c*time. */
Index: linux-2.6.15-rc1/kernel/sys.c
===================================================================
--- linux-2.6.15-rc1.orig/kernel/sys.c 2005-12-14 15:14:38.000000000 -0500
+++ linux-2.6.15-rc1/kernel/sys.c 2005-12-14 15:16:46.000000000 -0500
@@ -1179,7 +1179,8 @@ asmlinkage long sys_getpgid(pid_t pid)
if (p) {
retval = security_task_getpgid(p);
if (!retval)
- retval = virt_process_group(p);
+ retval = pid_to_vpid_ctx(process_group(p),
+ current);
}
read_unlock(&tasklist_lock);
return retval;
@@ -1199,7 +1200,7 @@ asmlinkage long sys_getpgrp(void)
asmlinkage long sys_getsid(pid_t pid)
{
if (!pid) {
- return pid_to_vpid(current->signal->session);
+ return pid_to_vpid_ctx(current->signal->session,current);
} else {
int retval;
struct task_struct *p;
@@ -1212,7 +1213,7 @@ asmlinkage long sys_getsid(pid_t pid)
if(p) {
retval = security_task_getsid(p);
if (!retval)
- retval = pid_to_vpid(p->signal->session);
+ retval = pid_to_vpid_ctx(p->signal->session, current);
}
read_unlock(&tasklist_lock);
return retval;
Index: linux-2.6.15-rc1/kernel/timer.c
===================================================================
--- linux-2.6.15-rc1.orig/kernel/timer.c 2005-12-14 15:12:33.000000000 -0500
+++ linux-2.6.15-rc1/kernel/timer.c 2005-12-14 15:16:46.000000000 -0500
@@ -968,7 +968,7 @@ asmlinkage long sys_getppid(void)

parent = me->group_leader->real_parent;
for (;;) {
- pid = task_tgid(parent);
+ pid = task_vtgid_ctx(parent, current);
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
{
struct task_struct *old = parent;
Index: linux-2.6.15-rc1/include/linux/sched.h
===================================================================
--- linux-2.6.15-rc1.orig/include/linux/sched.h 2005-12-14 15:14:37.000000000 -0500
+++ linux-2.6.15-rc1/include/linux/sched.h 2005-12-14 15:16:46.000000000 -0500
@@ -869,14 +869,29 @@ static inline pid_t process_group(const
* pid domain translation functions:
* - from kernel to user pid domain
*/
+static inline pid_t pid_to_vpid_ctx(pid_t pid, const struct task_struct *ctx)
+{
+ return pid;
+}
+
static inline pid_t pid_to_vpid(pid_t pid)
{
+ return pid_to_vpid_ctx(pid, current);
+}
+
+static inline pid_t pgid_to_vpgid_ctx(pid_t pid, const struct task_struct *ctx)
+{
+ int isgrp = (pid < 0) ;
+
+ if (isgrp) pid = -pid;
+ pid = pid_to_vpid_ctx(pid, ctx);
+ if (isgrp) pid = -pid;
return pid;
}

static inline pid_t pgid_to_vpgid(pid_t pid)
{
- return pid;
+ return pgid_to_vpgid_ctx(pid, current);
}

static inline pid_t vpid_to_pid(pid_t pid)
@@ -912,19 +927,37 @@ static inline pid_t task_tgid(const stru
return p->__tgid;
}

-static inline pid_t task_vpid(const struct task_struct *p)
+static inline pid_t task_vpid_ctx(const struct task_struct *p,
+ const struct task_struct *ctx)
{
return task_pid(p);
}

+static inline pid_t task_vpid(const struct task_struct *p)
+{
+ return task_vpid_ctx(p, p);
+}
+
+static inline pid_t task_vppid_ctx(const struct task_struct *p,
+ const struct task_struct *ctx)
+{
+ return task_vpid_ctx(p->parent, ctx);
+}
+
static inline pid_t task_vppid(const struct task_struct *p)
{
- return task_pid(p->parent);
+ return task_vppid_ctx(p, p);
+}
+
+static inline pid_t task_vtgid_ctx(const struct task_struct *p,
+ const struct task_struct *ctx)
+{
+ return pid_to_vpid_ctx(task_tgid(p), ctx);
}

static inline pid_t task_vtgid(const struct task_struct *p)
{
- return task_tgid(p);
+ return task_vtgid_ctx(p, p);
}

static inline pid_t virt_process_group(const struct task_struct *p)
Index: linux-2.6.15-rc1/fs/binfmt_elf.c
===================================================================
--- linux-2.6.15-rc1.orig/fs/binfmt_elf.c 2005-12-14 15:12:36.000000000 -0500
+++ linux-2.6.15-rc1/fs/binfmt_elf.c 2005-12-14 15:16:46.000000000 -0500
@@ -1273,7 +1273,7 @@ static void fill_prstatus(struct elf_prs
prstatus->pr_pid = task_vpid(p);
prstatus->pr_ppid = task_vppid(p);
prstatus->pr_pgrp = virt_process_group(p);
- prstatus->pr_sid = pid_to_vpid(p->signal->session);
+ prstatus->pr_sid = pid_to_vpid_ctx(p->signal->session, p);
if (thread_group_leader(p)) {
/*
* This is the record for the group leader. Add in the
@@ -1319,7 +1319,7 @@ static int fill_psinfo(struct elf_prpsin
psinfo->pr_pid = task_vpid(p);
psinfo->pr_ppid = task_vppid(p);
psinfo->pr_pgrp = virt_process_group(p);
- psinfo->pr_sid = pid_to_vpid(p->signal->session);
+ psinfo->pr_sid = pid_to_vpid_ctx(p->signal->session, p);

i = p->state ? ffz(~p->state) + 1 : 0;
psinfo->pr_state = i;

--
-
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