1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * tsacct.c - System accounting over taskstats interface
4 *
5 * Copyright (C) Jay Lan,	<jlan@sgi.com>
6 */
7
8#include <linux/kernel.h>
9#include <linux/sched/signal.h>
10#include <linux/sched/mm.h>
11#include <linux/sched/cputime.h>
12#include <linux/tsacct_kern.h>
13#include <linux/acct.h>
14#include <linux/jiffies.h>
15#include <linux/mm.h>
16
17/*
18 * fill in basic accounting fields
19 */
20void bacct_add_tsk(struct user_namespace *user_ns,
21		   struct pid_namespace *pid_ns,
22		   struct taskstats *stats, struct task_struct *tsk)
23{
24	const struct cred *tcred;
25	u64 utime, stime, utimescaled, stimescaled;
26	u64 now_ns, delta;
27	time64_t btime;
28
29	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
30
31	/* calculate task elapsed time in nsec */
32	now_ns = ktime_get_ns();
33	/* store whole group time first */
34	delta = now_ns - tsk->group_leader->start_time;
35	/* Convert to micro seconds */
36	do_div(delta, NSEC_PER_USEC);
37	stats->ac_tgetime = delta;
38	delta = now_ns - tsk->start_time;
39	do_div(delta, NSEC_PER_USEC);
40	stats->ac_etime = delta;
41	/* Convert to seconds for btime (note y2106 limit) */
42	btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC);
43	stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
44	stats->ac_btime64 = btime;
45
46	if (tsk->flags & PF_EXITING)
47		stats->ac_exitcode = tsk->exit_code;
48	if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC))
49		stats->ac_flag |= AFORK;
50	if (tsk->flags & PF_SUPERPRIV)
51		stats->ac_flag |= ASU;
52	if (tsk->flags & PF_DUMPCORE)
53		stats->ac_flag |= ACORE;
54	if (tsk->flags & PF_SIGNALED)
55		stats->ac_flag |= AXSIG;
56	stats->ac_nice	 = task_nice(tsk);
57	stats->ac_sched	 = tsk->policy;
58	stats->ac_pid	 = task_pid_nr_ns(tsk, pid_ns);
59	stats->ac_tgid   = task_tgid_nr_ns(tsk, pid_ns);
60	rcu_read_lock();
61	tcred = __task_cred(tsk);
62	stats->ac_uid	 = from_kuid_munged(user_ns, tcred->uid);
63	stats->ac_gid	 = from_kgid_munged(user_ns, tcred->gid);
64	stats->ac_ppid	 = pid_alive(tsk) ?
65		task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
66	rcu_read_unlock();
67
68	task_cputime(tsk, &utime, &stime);
69	stats->ac_utime = div_u64(utime, NSEC_PER_USEC);
70	stats->ac_stime = div_u64(stime, NSEC_PER_USEC);
71
72	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
73	stats->ac_utimescaled = div_u64(utimescaled, NSEC_PER_USEC);
74	stats->ac_stimescaled = div_u64(stimescaled, NSEC_PER_USEC);
75
76	stats->ac_minflt = tsk->min_flt;
77	stats->ac_majflt = tsk->maj_flt;
78
79	strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
80}
81
82
83#ifdef CONFIG_TASK_XACCT
84
85#define KB 1024
86#define MB (1024*KB)
87#define KB_MASK (~(KB-1))
88/*
89 * fill in extended accounting fields
90 */
91void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
92{
93	struct mm_struct *mm;
94
95	/* convert pages-nsec/1024 to Mbyte-usec, see __acct_update_integrals */
96	stats->coremem = p->acct_rss_mem1 * PAGE_SIZE;
97	do_div(stats->coremem, 1000 * KB);
98	stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE;
99	do_div(stats->virtmem, 1000 * KB);
100	mm = get_task_mm(p);
101	if (mm) {
102		/* adjust to KB unit */
103		stats->hiwater_rss   = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
104		stats->hiwater_vm    = get_mm_hiwater_vm(mm)  * PAGE_SIZE / KB;
105		mmput(mm);
106	}
107	stats->read_char	= p->ioac.rchar & KB_MASK;
108	stats->write_char	= p->ioac.wchar & KB_MASK;
109	stats->read_syscalls	= p->ioac.syscr & KB_MASK;
110	stats->write_syscalls	= p->ioac.syscw & KB_MASK;
111#ifdef CONFIG_TASK_IO_ACCOUNTING
112	stats->read_bytes	= p->ioac.read_bytes & KB_MASK;
113	stats->write_bytes	= p->ioac.write_bytes & KB_MASK;
114	stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes & KB_MASK;
115#else
116	stats->read_bytes	= 0;
117	stats->write_bytes	= 0;
118	stats->cancelled_write_bytes = 0;
119#endif
120}
121#undef KB
122#undef MB
123
124static void __acct_update_integrals(struct task_struct *tsk,
125				    u64 utime, u64 stime)
126{
127	u64 time, delta;
128
129	if (!likely(tsk->mm))
130		return;
131
132	time = stime + utime;
133	delta = time - tsk->acct_timexpd;
134
135	if (delta < TICK_NSEC)
136		return;
137
138	tsk->acct_timexpd = time;
139	/*
140	 * Divide by 1024 to avoid overflow, and to avoid division.
141	 * The final unit reported to userspace is Mbyte-usecs,
142	 * the rest of the math is done in xacct_add_tsk.
143	 */
144	tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm) >> 10;
145	tsk->acct_vm_mem1 += delta * READ_ONCE(tsk->mm->total_vm) >> 10;
146}
147
148/**
149 * acct_update_integrals - update mm integral fields in task_struct
150 * @tsk: task_struct for accounting
151 */
152void acct_update_integrals(struct task_struct *tsk)
153{
154	u64 utime, stime;
155	unsigned long flags;
156
157	local_irq_save(flags);
158	task_cputime(tsk, &utime, &stime);
159	__acct_update_integrals(tsk, utime, stime);
160	local_irq_restore(flags);
161}
162
163/**
164 * acct_account_cputime - update mm integral after cputime update
165 * @tsk: task_struct for accounting
166 */
167void acct_account_cputime(struct task_struct *tsk)
168{
169	__acct_update_integrals(tsk, tsk->utime, tsk->stime);
170}
171
172/**
173 * acct_clear_integrals - clear the mm integral fields in task_struct
174 * @tsk: task_struct whose accounting fields are cleared
175 */
176void acct_clear_integrals(struct task_struct *tsk)
177{
178	tsk->acct_timexpd = 0;
179	tsk->acct_rss_mem1 = 0;
180	tsk->acct_vm_mem1 = 0;
181}
182#endif
183