diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-28 11:43:54 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-28 11:43:54 -0800 |
commit | bb26c6c29b7cc9f39e491b074b09f3c284738d36 (patch) | |
tree | c7867af2bb4ff0feae889183efcd4d79b0f9a325 /lib/is_single_threaded.c | |
parent | e14e61e967f2b3bdf23f05e4ae5b9aa830151a44 (diff) | |
parent | cbacc2c7f066a1e01b33b0e27ae5efbf534bc2db (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (105 commits)
SELinux: don't check permissions for kernel mounts
security: pass mount flags to security_sb_kern_mount()
SELinux: correctly detect proc filesystems of the form "proc/foo"
Audit: Log TIOCSTI
user namespaces: document CFS behavior
user namespaces: require cap_set{ug}id for CLONE_NEWUSER
user namespaces: let user_ns be cloned with fairsched
CRED: fix sparse warnings
User namespaces: use the current_user_ns() macro
User namespaces: set of cleanups (v2)
nfsctl: add headers for credentials
coda: fix creds reference
capabilities: define get_vfs_caps_from_disk when file caps are not enabled
CRED: Allow kernel services to override LSM settings for task actions
CRED: Add a kernel_service object class to SELinux
CRED: Differentiate objective and effective subjective credentials on a task
CRED: Documentation
CRED: Use creds in file structs
CRED: Prettify commoncap.c
CRED: Make execve() take advantage of copy-on-write credentials
...
Diffstat (limited to 'lib/is_single_threaded.c')
-rw-r--r-- | lib/is_single_threaded.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/is_single_threaded.c b/lib/is_single_threaded.c new file mode 100644 index 00000000000..f1ed2fe76c6 --- /dev/null +++ b/lib/is_single_threaded.c @@ -0,0 +1,45 @@ +/* Function to determine if a thread group is single threaded or not + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * - Derived from security/selinux/hooks.c + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/sched.h> + +/** + * is_single_threaded - Determine if a thread group is single-threaded or not + * @p: A task in the thread group in question + * + * This returns true if the thread group to which a task belongs is single + * threaded, false if it is not. + */ +bool is_single_threaded(struct task_struct *p) +{ + struct task_struct *g, *t; + struct mm_struct *mm = p->mm; + + if (atomic_read(&p->signal->count) != 1) + goto no; + + if (atomic_read(&p->mm->mm_users) != 1) { + read_lock(&tasklist_lock); + do_each_thread(g, t) { + if (t->mm == mm && t != p) + goto no_unlock; + } while_each_thread(g, t); + read_unlock(&tasklist_lock); + } + + return true; + +no_unlock: + read_unlock(&tasklist_lock); +no: + return false; +} |