Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2
3#ifndef _UAPI_LINUX_PIDFD_H
4#define _UAPI_LINUX_PIDFD_H
5
6#include <linux/types.h>
7#include <linux/fcntl.h>
8#include <linux/ioctl.h>
9
10/* Flags for pidfd_open(). */
11#define PIDFD_NONBLOCK O_NONBLOCK
12#define PIDFD_THREAD O_EXCL
13#ifdef __KERNEL__
14#include <linux/sched.h>
15#define PIDFD_STALE CLONE_PIDFD
16#endif
17
18/* Flags for pidfd_send_signal(). */
19#define PIDFD_SIGNAL_THREAD (1UL << 0)
20#define PIDFD_SIGNAL_THREAD_GROUP (1UL << 1)
21#define PIDFD_SIGNAL_PROCESS_GROUP (1UL << 2)
22
23/* Flags for pidfd_info. */
24#define PIDFD_INFO_PID (1UL << 0) /* Always returned, even if not requested */
25#define PIDFD_INFO_CREDS (1UL << 1) /* Always returned, even if not requested */
26#define PIDFD_INFO_CGROUPID (1UL << 2) /* Always returned if available, even if not requested */
27#define PIDFD_INFO_EXIT (1UL << 3) /* Only returned if requested. */
28#define PIDFD_INFO_COREDUMP (1UL << 4) /* Only returned if requested. */
29
30#define PIDFD_INFO_SIZE_VER0 64 /* sizeof first published struct */
31
32/*
33 * Values for @coredump_mask in pidfd_info.
34 * Only valid if PIDFD_INFO_COREDUMP is set in @mask.
35 *
36 * Note, the @PIDFD_COREDUMP_ROOT flag indicates that the generated
37 * coredump should be treated as sensitive and access should only be
38 * granted to privileged users.
39 */
40#define PIDFD_COREDUMPED (1U << 0) /* Did crash and... */
41#define PIDFD_COREDUMP_SKIP (1U << 1) /* coredumping generation was skipped. */
42#define PIDFD_COREDUMP_USER (1U << 2) /* coredump was done as the user. */
43#define PIDFD_COREDUMP_ROOT (1U << 3) /* coredump was done as root. */
44
45/*
46 * The concept of process and threads in userland and the kernel is a confusing
47 * one - within the kernel every thread is a 'task' with its own individual PID,
48 * however from userland's point of view threads are grouped by a single PID,
49 * which is that of the 'thread group leader', typically the first thread
50 * spawned.
51 *
52 * To cut the Gideon knot, for internal kernel usage, we refer to
53 * PIDFD_SELF_THREAD to refer to the current thread (or task from a kernel
54 * perspective), and PIDFD_SELF_THREAD_GROUP to refer to the current thread
55 * group leader...
56 */
57#define PIDFD_SELF_THREAD -10000 /* Current thread. */
58#define PIDFD_SELF_THREAD_GROUP -20000 /* Current thread group leader. */
59
60/*
61 * ...and for userland we make life simpler - PIDFD_SELF refers to the current
62 * thread, PIDFD_SELF_PROCESS refers to the process thread group leader.
63 *
64 * For nearly all practical uses, a user will want to use PIDFD_SELF.
65 */
66#define PIDFD_SELF PIDFD_SELF_THREAD
67#define PIDFD_SELF_PROCESS PIDFD_SELF_THREAD_GROUP
68
69struct pidfd_info {
70 /*
71 * This mask is similar to the request_mask in statx(2).
72 *
73 * Userspace indicates what extensions or expensive-to-calculate fields
74 * they want by setting the corresponding bits in mask. The kernel
75 * will ignore bits that it does not know about.
76 *
77 * When filling the structure, the kernel will only set bits
78 * corresponding to the fields that were actually filled by the kernel.
79 * This also includes any future extensions that might be automatically
80 * filled. If the structure size is too small to contain a field
81 * (requested or not), to avoid confusion the mask will not
82 * contain a bit for that field.
83 *
84 * As such, userspace MUST verify that mask contains the
85 * corresponding flags after the ioctl(2) returns to ensure that it is
86 * using valid data.
87 */
88 __u64 mask;
89 /*
90 * The information contained in the following fields might be stale at the
91 * time it is received, as the target process might have exited as soon as
92 * the IOCTL was processed, and there is no way to avoid that. However, it
93 * is guaranteed that if the call was successful, then the information was
94 * correct and referred to the intended process at the time the work was
95 * performed. */
96 __u64 cgroupid;
97 __u32 pid;
98 __u32 tgid;
99 __u32 ppid;
100 __u32 ruid;
101 __u32 rgid;
102 __u32 euid;
103 __u32 egid;
104 __u32 suid;
105 __u32 sgid;
106 __u32 fsuid;
107 __u32 fsgid;
108 __s32 exit_code;
109 __u32 coredump_mask;
110 __u32 __spare1;
111};
112
113#define PIDFS_IOCTL_MAGIC 0xFF
114
115#define PIDFD_GET_CGROUP_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 1)
116#define PIDFD_GET_IPC_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 2)
117#define PIDFD_GET_MNT_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 3)
118#define PIDFD_GET_NET_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 4)
119#define PIDFD_GET_PID_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 5)
120#define PIDFD_GET_PID_FOR_CHILDREN_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 6)
121#define PIDFD_GET_TIME_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 7)
122#define PIDFD_GET_TIME_FOR_CHILDREN_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 8)
123#define PIDFD_GET_USER_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 9)
124#define PIDFD_GET_UTS_NAMESPACE _IO(PIDFS_IOCTL_MAGIC, 10)
125#define PIDFD_GET_INFO _IOWR(PIDFS_IOCTL_MAGIC, 11, struct pidfd_info)
126
127#endif /* _UAPI_LINUX_PIDFD_H */