Set the pid number for a restored task. This is purely a toy, as it
only sets the pidnr in the lowest level pid namespace.
Signed-off-by: Serge Hallyn <serue@xxxxxxxxxx>
---
kernel/fork.c | 5 +++++
kernel/pid.c | 19 +++++++++++++++++++
2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 0e43f69..41c46d2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1685,6 +1685,8 @@ int unshare_files(struct files_struct **displaced)
char buf[CKPT_SIZE];
char exe_filename[PAGE_SIZE];
+extern int choose_pidmap(struct pid *pid, int new);
+
/*
* userspace will already have made us a new pidns
*/
@@ -1717,6 +1719,9 @@ long do_restore(unsigned int fd,
if (nr_scanned != 2)
return -EINVAL;
+ ret = choose_pidmap(task_pid(current), pid);
+ if (!ret)
+ return -EAGAIN;
ret = do_execve(exe_filename, argv, envp, regs);
out:
diff --git a/kernel/pid.c b/kernel/pid.c
index 30bd5d4..88a5e2a 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -122,6 +122,25 @@ static void free_pidmap(struct upid *upid)
atomic_inc(&map->nr_free);
}
+int choose_pidmap(struct pid *pid, int new)
+{
+ struct pidmap *map;
+ int level = pid->level;
+ struct upid *upid = &pid->numbers[level];
+ struct pid_namespace *pid_ns = upid->ns;
+ int old = upid->nr;
+
+ map = &pid_ns->pidmap[new/BITS_PER_PAGE];
+ if (!test_and_set_bit(new, map->page)) {
+ map = &pid_ns->pidmap[old/BITS_PER_PAGE];
+ clear_bit(old, map->page);
+ upid->nr = new;
+ return 1;
+ }
+
+ return 0;
+}
+
static int alloc_pidmap(struct pid_namespace *pid_ns)
{
int i, offset, max_scan, pid, last = pid_ns->last_pid;
--
1.5.4.3
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