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c69e8d9c01
Use RCU to access another task's creds and to release a task's own creds. This means that it will be possible for the credentials of a task to be replaced without another task (a) requiring a full lock to read them, and (b) seeing deallocated memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
152 lines
4.2 KiB
C
152 lines
4.2 KiB
C
/*
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* tsacct.c - System accounting over taskstats interface
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*
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* Copyright (C) Jay Lan, <jlan@sgi.com>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/tsacct_kern.h>
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#include <linux/acct.h>
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#include <linux/jiffies.h>
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/*
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* fill in basic accounting fields
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*/
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void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
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{
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const struct cred *tcred;
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struct timespec uptime, ts;
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u64 ac_etime;
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BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
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/* calculate task elapsed time in timespec */
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do_posix_clock_monotonic_gettime(&uptime);
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ts = timespec_sub(uptime, tsk->start_time);
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/* rebase elapsed time to usec (should never be negative) */
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ac_etime = timespec_to_ns(&ts);
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do_div(ac_etime, NSEC_PER_USEC);
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stats->ac_etime = ac_etime;
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stats->ac_btime = get_seconds() - ts.tv_sec;
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if (thread_group_leader(tsk)) {
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stats->ac_exitcode = tsk->exit_code;
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if (tsk->flags & PF_FORKNOEXEC)
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stats->ac_flag |= AFORK;
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}
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if (tsk->flags & PF_SUPERPRIV)
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stats->ac_flag |= ASU;
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if (tsk->flags & PF_DUMPCORE)
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stats->ac_flag |= ACORE;
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if (tsk->flags & PF_SIGNALED)
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stats->ac_flag |= AXSIG;
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stats->ac_nice = task_nice(tsk);
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stats->ac_sched = tsk->policy;
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stats->ac_pid = tsk->pid;
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rcu_read_lock();
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tcred = __task_cred(tsk);
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stats->ac_uid = tcred->uid;
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stats->ac_gid = tcred->gid;
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stats->ac_ppid = pid_alive(tsk) ?
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rcu_dereference(tsk->real_parent)->tgid : 0;
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rcu_read_unlock();
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stats->ac_utime = cputime_to_msecs(tsk->utime) * USEC_PER_MSEC;
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stats->ac_stime = cputime_to_msecs(tsk->stime) * USEC_PER_MSEC;
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stats->ac_utimescaled =
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cputime_to_msecs(tsk->utimescaled) * USEC_PER_MSEC;
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stats->ac_stimescaled =
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cputime_to_msecs(tsk->stimescaled) * USEC_PER_MSEC;
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stats->ac_minflt = tsk->min_flt;
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stats->ac_majflt = tsk->maj_flt;
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strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
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}
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#ifdef CONFIG_TASK_XACCT
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#define KB 1024
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#define MB (1024*KB)
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/*
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* fill in extended accounting fields
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*/
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void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
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{
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struct mm_struct *mm;
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/* convert pages-usec to Mbyte-usec */
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stats->coremem = p->acct_rss_mem1 * PAGE_SIZE / MB;
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stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE / MB;
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mm = get_task_mm(p);
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if (mm) {
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/* adjust to KB unit */
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stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB;
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stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB;
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mmput(mm);
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}
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stats->read_char = p->ioac.rchar;
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stats->write_char = p->ioac.wchar;
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stats->read_syscalls = p->ioac.syscr;
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stats->write_syscalls = p->ioac.syscw;
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#ifdef CONFIG_TASK_IO_ACCOUNTING
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stats->read_bytes = p->ioac.read_bytes;
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stats->write_bytes = p->ioac.write_bytes;
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stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes;
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#else
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stats->read_bytes = 0;
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stats->write_bytes = 0;
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stats->cancelled_write_bytes = 0;
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#endif
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}
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#undef KB
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#undef MB
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/**
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* acct_update_integrals - update mm integral fields in task_struct
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* @tsk: task_struct for accounting
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*/
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void acct_update_integrals(struct task_struct *tsk)
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{
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if (likely(tsk->mm)) {
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cputime_t time, dtime;
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struct timeval value;
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u64 delta;
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time = tsk->stime + tsk->utime;
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dtime = cputime_sub(time, tsk->acct_timexpd);
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jiffies_to_timeval(cputime_to_jiffies(dtime), &value);
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delta = value.tv_sec;
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delta = delta * USEC_PER_SEC + value.tv_usec;
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if (delta == 0)
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return;
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tsk->acct_timexpd = time;
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tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm);
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tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;
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}
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}
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/**
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* acct_clear_integrals - clear the mm integral fields in task_struct
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* @tsk: task_struct whose accounting fields are cleared
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*/
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void acct_clear_integrals(struct task_struct *tsk)
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{
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tsk->acct_timexpd = 0;
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tsk->acct_rss_mem1 = 0;
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tsk->acct_vm_mem1 = 0;
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}
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#endif
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