forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
603 lines
15 KiB
603 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* linux/kernel/acct.c |
|
* |
|
* BSD Process Accounting for Linux |
|
* |
|
* Author: Marco van Wieringen <[email protected]> |
|
* |
|
* Some code based on ideas and code from: |
|
* Thomas K. Dyas <[email protected]> |
|
* |
|
* This file implements BSD-style process accounting. Whenever any |
|
* process exits, an accounting record of type "struct acct" is |
|
* written to the file specified with the acct() system call. It is |
|
* up to user-level programs to do useful things with the accounting |
|
* log. The kernel just provides the raw accounting information. |
|
* |
|
* (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V. |
|
* |
|
* Plugged two leaks. 1) It didn't return acct_file into the free_filps if |
|
* the file happened to be read-only. 2) If the accounting was suspended |
|
* due to the lack of space it happily allowed to reopen it and completely |
|
* lost the old acct_file. 3/10/98, Al Viro. |
|
* |
|
* Now we silently close acct_file on attempt to reopen. Cleaned sys_acct(). |
|
* XTerms and EMACS are manifestations of pure evil. 21/10/98, AV. |
|
* |
|
* Fixed a nasty interaction with sys_umount(). If the accounting |
|
* was suspeneded we failed to stop it on umount(). Messy. |
|
* Another one: remount to readonly didn't stop accounting. |
|
* Question: what should we do if we have CAP_SYS_ADMIN but not |
|
* CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY |
|
* unless we are messing with the root. In that case we are getting a |
|
* real mess with do_remount_sb(). 9/11/98, AV. |
|
* |
|
* Fixed a bunch of races (and pair of leaks). Probably not the best way, |
|
* but this one obviously doesn't introduce deadlocks. Later. BTW, found |
|
* one race (and leak) in BSD implementation. |
|
* OK, that's better. ANOTHER race and leak in BSD variant. There always |
|
* is one more bug... 10/11/98, AV. |
|
* |
|
* Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold |
|
* ->mmap_lock to walk the vma list of current->mm. Nasty, since it leaks |
|
* a struct file opened for write. Fixed. 2/6/2000, AV. |
|
*/ |
|
|
|
#include <linux/mm.h> |
|
#include <linux/slab.h> |
|
#include <linux/acct.h> |
|
#include <linux/capability.h> |
|
#include <linux/file.h> |
|
#include <linux/tty.h> |
|
#include <linux/security.h> |
|
#include <linux/vfs.h> |
|
#include <linux/jiffies.h> |
|
#include <linux/times.h> |
|
#include <linux/syscalls.h> |
|
#include <linux/mount.h> |
|
#include <linux/uaccess.h> |
|
#include <linux/sched/cputime.h> |
|
|
|
#include <asm/div64.h> |
|
#include <linux/blkdev.h> /* sector_div */ |
|
#include <linux/pid_namespace.h> |
|
#include <linux/fs_pin.h> |
|
|
|
/* |
|
* These constants control the amount of freespace that suspend and |
|
* resume the process accounting system, and the time delay between |
|
* each check. |
|
* Turned into sysctl-controllable parameters. AV, 12/11/98 |
|
*/ |
|
|
|
int acct_parm[3] = {4, 2, 30}; |
|
#define RESUME (acct_parm[0]) /* >foo% free space - resume */ |
|
#define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */ |
|
#define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */ |
|
|
|
/* |
|
* External references and all of the globals. |
|
*/ |
|
|
|
struct bsd_acct_struct { |
|
struct fs_pin pin; |
|
atomic_long_t count; |
|
struct rcu_head rcu; |
|
struct mutex lock; |
|
int active; |
|
unsigned long needcheck; |
|
struct file *file; |
|
struct pid_namespace *ns; |
|
struct work_struct work; |
|
struct completion done; |
|
}; |
|
|
|
static void do_acct_process(struct bsd_acct_struct *acct); |
|
|
|
/* |
|
* Check the amount of free space and suspend/resume accordingly. |
|
*/ |
|
static int check_free_space(struct bsd_acct_struct *acct) |
|
{ |
|
struct kstatfs sbuf; |
|
|
|
if (time_is_after_jiffies(acct->needcheck)) |
|
goto out; |
|
|
|
/* May block */ |
|
if (vfs_statfs(&acct->file->f_path, &sbuf)) |
|
goto out; |
|
|
|
if (acct->active) { |
|
u64 suspend = sbuf.f_blocks * SUSPEND; |
|
do_div(suspend, 100); |
|
if (sbuf.f_bavail <= suspend) { |
|
acct->active = 0; |
|
pr_info("Process accounting paused\n"); |
|
} |
|
} else { |
|
u64 resume = sbuf.f_blocks * RESUME; |
|
do_div(resume, 100); |
|
if (sbuf.f_bavail >= resume) { |
|
acct->active = 1; |
|
pr_info("Process accounting resumed\n"); |
|
} |
|
} |
|
|
|
acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; |
|
out: |
|
return acct->active; |
|
} |
|
|
|
static void acct_put(struct bsd_acct_struct *p) |
|
{ |
|
if (atomic_long_dec_and_test(&p->count)) |
|
kfree_rcu(p, rcu); |
|
} |
|
|
|
static inline struct bsd_acct_struct *to_acct(struct fs_pin *p) |
|
{ |
|
return p ? container_of(p, struct bsd_acct_struct, pin) : NULL; |
|
} |
|
|
|
static struct bsd_acct_struct *acct_get(struct pid_namespace *ns) |
|
{ |
|
struct bsd_acct_struct *res; |
|
again: |
|
smp_rmb(); |
|
rcu_read_lock(); |
|
res = to_acct(READ_ONCE(ns->bacct)); |
|
if (!res) { |
|
rcu_read_unlock(); |
|
return NULL; |
|
} |
|
if (!atomic_long_inc_not_zero(&res->count)) { |
|
rcu_read_unlock(); |
|
cpu_relax(); |
|
goto again; |
|
} |
|
rcu_read_unlock(); |
|
mutex_lock(&res->lock); |
|
if (res != to_acct(READ_ONCE(ns->bacct))) { |
|
mutex_unlock(&res->lock); |
|
acct_put(res); |
|
goto again; |
|
} |
|
return res; |
|
} |
|
|
|
static void acct_pin_kill(struct fs_pin *pin) |
|
{ |
|
struct bsd_acct_struct *acct = to_acct(pin); |
|
mutex_lock(&acct->lock); |
|
do_acct_process(acct); |
|
schedule_work(&acct->work); |
|
wait_for_completion(&acct->done); |
|
cmpxchg(&acct->ns->bacct, pin, NULL); |
|
mutex_unlock(&acct->lock); |
|
pin_remove(pin); |
|
acct_put(acct); |
|
} |
|
|
|
static void close_work(struct work_struct *work) |
|
{ |
|
struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work); |
|
struct file *file = acct->file; |
|
if (file->f_op->flush) |
|
file->f_op->flush(file, NULL); |
|
__fput_sync(file); |
|
complete(&acct->done); |
|
} |
|
|
|
static int acct_on(struct filename *pathname) |
|
{ |
|
struct file *file; |
|
struct vfsmount *mnt, *internal; |
|
struct pid_namespace *ns = task_active_pid_ns(current); |
|
struct bsd_acct_struct *acct; |
|
struct fs_pin *old; |
|
int err; |
|
|
|
acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL); |
|
if (!acct) |
|
return -ENOMEM; |
|
|
|
/* Difference from BSD - they don't do O_APPEND */ |
|
file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0); |
|
if (IS_ERR(file)) { |
|
kfree(acct); |
|
return PTR_ERR(file); |
|
} |
|
|
|
if (!S_ISREG(file_inode(file)->i_mode)) { |
|
kfree(acct); |
|
filp_close(file, NULL); |
|
return -EACCES; |
|
} |
|
|
|
if (!(file->f_mode & FMODE_CAN_WRITE)) { |
|
kfree(acct); |
|
filp_close(file, NULL); |
|
return -EIO; |
|
} |
|
internal = mnt_clone_internal(&file->f_path); |
|
if (IS_ERR(internal)) { |
|
kfree(acct); |
|
filp_close(file, NULL); |
|
return PTR_ERR(internal); |
|
} |
|
err = __mnt_want_write(internal); |
|
if (err) { |
|
mntput(internal); |
|
kfree(acct); |
|
filp_close(file, NULL); |
|
return err; |
|
} |
|
mnt = file->f_path.mnt; |
|
file->f_path.mnt = internal; |
|
|
|
atomic_long_set(&acct->count, 1); |
|
init_fs_pin(&acct->pin, acct_pin_kill); |
|
acct->file = file; |
|
acct->needcheck = jiffies; |
|
acct->ns = ns; |
|
mutex_init(&acct->lock); |
|
INIT_WORK(&acct->work, close_work); |
|
init_completion(&acct->done); |
|
mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */ |
|
pin_insert(&acct->pin, mnt); |
|
|
|
rcu_read_lock(); |
|
old = xchg(&ns->bacct, &acct->pin); |
|
mutex_unlock(&acct->lock); |
|
pin_kill(old); |
|
__mnt_drop_write(mnt); |
|
mntput(mnt); |
|
return 0; |
|
} |
|
|
|
static DEFINE_MUTEX(acct_on_mutex); |
|
|
|
/** |
|
* sys_acct - enable/disable process accounting |
|
* @name: file name for accounting records or NULL to shutdown accounting |
|
* |
|
* sys_acct() is the only system call needed to implement process |
|
* accounting. It takes the name of the file where accounting records |
|
* should be written. If the filename is NULL, accounting will be |
|
* shutdown. |
|
* |
|
* Returns: 0 for success or negative errno values for failure. |
|
*/ |
|
SYSCALL_DEFINE1(acct, const char __user *, name) |
|
{ |
|
int error = 0; |
|
|
|
if (!capable(CAP_SYS_PACCT)) |
|
return -EPERM; |
|
|
|
if (name) { |
|
struct filename *tmp = getname(name); |
|
|
|
if (IS_ERR(tmp)) |
|
return PTR_ERR(tmp); |
|
mutex_lock(&acct_on_mutex); |
|
error = acct_on(tmp); |
|
mutex_unlock(&acct_on_mutex); |
|
putname(tmp); |
|
} else { |
|
rcu_read_lock(); |
|
pin_kill(task_active_pid_ns(current)->bacct); |
|
} |
|
|
|
return error; |
|
} |
|
|
|
void acct_exit_ns(struct pid_namespace *ns) |
|
{ |
|
rcu_read_lock(); |
|
pin_kill(ns->bacct); |
|
} |
|
|
|
/* |
|
* encode an unsigned long into a comp_t |
|
* |
|
* This routine has been adopted from the encode_comp_t() function in |
|
* the kern_acct.c file of the FreeBSD operating system. The encoding |
|
* is a 13-bit fraction with a 3-bit (base 8) exponent. |
|
*/ |
|
|
|
#define MANTSIZE 13 /* 13 bit mantissa. */ |
|
#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ |
|
#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ |
|
|
|
static comp_t encode_comp_t(unsigned long value) |
|
{ |
|
int exp, rnd; |
|
|
|
exp = rnd = 0; |
|
while (value > MAXFRACT) { |
|
rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */ |
|
value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ |
|
exp++; |
|
} |
|
|
|
/* |
|
* If we need to round up, do it (and handle overflow correctly). |
|
*/ |
|
if (rnd && (++value > MAXFRACT)) { |
|
value >>= EXPSIZE; |
|
exp++; |
|
} |
|
|
|
/* |
|
* Clean it up and polish it off. |
|
*/ |
|
exp <<= MANTSIZE; /* Shift the exponent into place */ |
|
exp += value; /* and add on the mantissa. */ |
|
return exp; |
|
} |
|
|
|
#if ACCT_VERSION == 1 || ACCT_VERSION == 2 |
|
/* |
|
* encode an u64 into a comp2_t (24 bits) |
|
* |
|
* Format: 5 bit base 2 exponent, 20 bits mantissa. |
|
* The leading bit of the mantissa is not stored, but implied for |
|
* non-zero exponents. |
|
* Largest encodable value is 50 bits. |
|
*/ |
|
|
|
#define MANTSIZE2 20 /* 20 bit mantissa. */ |
|
#define EXPSIZE2 5 /* 5 bit base 2 exponent. */ |
|
#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */ |
|
#define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */ |
|
|
|
static comp2_t encode_comp2_t(u64 value) |
|
{ |
|
int exp, rnd; |
|
|
|
exp = (value > (MAXFRACT2>>1)); |
|
rnd = 0; |
|
while (value > MAXFRACT2) { |
|
rnd = value & 1; |
|
value >>= 1; |
|
exp++; |
|
} |
|
|
|
/* |
|
* If we need to round up, do it (and handle overflow correctly). |
|
*/ |
|
if (rnd && (++value > MAXFRACT2)) { |
|
value >>= 1; |
|
exp++; |
|
} |
|
|
|
if (exp > MAXEXP2) { |
|
/* Overflow. Return largest representable number instead. */ |
|
return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1; |
|
} else { |
|
return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1)); |
|
} |
|
} |
|
#elif ACCT_VERSION == 3 |
|
/* |
|
* encode an u64 into a 32 bit IEEE float |
|
*/ |
|
static u32 encode_float(u64 value) |
|
{ |
|
unsigned exp = 190; |
|
unsigned u; |
|
|
|
if (value == 0) |
|
return 0; |
|
while ((s64)value > 0) { |
|
value <<= 1; |
|
exp--; |
|
} |
|
u = (u32)(value >> 40) & 0x7fffffu; |
|
return u | (exp << 23); |
|
} |
|
#endif |
|
|
|
/* |
|
* Write an accounting entry for an exiting process |
|
* |
|
* The acct_process() call is the workhorse of the process |
|
* accounting system. The struct acct is built here and then written |
|
* into the accounting file. This function should only be called from |
|
* do_exit() or when switching to a different output file. |
|
*/ |
|
|
|
static void fill_ac(acct_t *ac) |
|
{ |
|
struct pacct_struct *pacct = ¤t->signal->pacct; |
|
u64 elapsed, run_time; |
|
time64_t btime; |
|
struct tty_struct *tty; |
|
|
|
/* |
|
* Fill the accounting struct with the needed info as recorded |
|
* by the different kernel functions. |
|
*/ |
|
memset(ac, 0, sizeof(acct_t)); |
|
|
|
ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER; |
|
strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm)); |
|
|
|
/* calculate run_time in nsec*/ |
|
run_time = ktime_get_ns(); |
|
run_time -= current->group_leader->start_time; |
|
/* convert nsec -> AHZ */ |
|
elapsed = nsec_to_AHZ(run_time); |
|
#if ACCT_VERSION == 3 |
|
ac->ac_etime = encode_float(elapsed); |
|
#else |
|
ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? |
|
(unsigned long) elapsed : (unsigned long) -1l); |
|
#endif |
|
#if ACCT_VERSION == 1 || ACCT_VERSION == 2 |
|
{ |
|
/* new enlarged etime field */ |
|
comp2_t etime = encode_comp2_t(elapsed); |
|
|
|
ac->ac_etime_hi = etime >> 16; |
|
ac->ac_etime_lo = (u16) etime; |
|
} |
|
#endif |
|
do_div(elapsed, AHZ); |
|
btime = ktime_get_real_seconds() - elapsed; |
|
ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); |
|
#if ACCT_VERSION==2 |
|
ac->ac_ahz = AHZ; |
|
#endif |
|
|
|
spin_lock_irq(¤t->sighand->siglock); |
|
tty = current->signal->tty; /* Safe as we hold the siglock */ |
|
ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0; |
|
ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime)); |
|
ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime)); |
|
ac->ac_flag = pacct->ac_flag; |
|
ac->ac_mem = encode_comp_t(pacct->ac_mem); |
|
ac->ac_minflt = encode_comp_t(pacct->ac_minflt); |
|
ac->ac_majflt = encode_comp_t(pacct->ac_majflt); |
|
ac->ac_exitcode = pacct->ac_exitcode; |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
} |
|
/* |
|
* do_acct_process does all actual work. Caller holds the reference to file. |
|
*/ |
|
static void do_acct_process(struct bsd_acct_struct *acct) |
|
{ |
|
acct_t ac; |
|
unsigned long flim; |
|
const struct cred *orig_cred; |
|
struct file *file = acct->file; |
|
|
|
/* |
|
* Accounting records are not subject to resource limits. |
|
*/ |
|
flim = rlimit(RLIMIT_FSIZE); |
|
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; |
|
/* Perform file operations on behalf of whoever enabled accounting */ |
|
orig_cred = override_creds(file->f_cred); |
|
|
|
/* |
|
* First check to see if there is enough free_space to continue |
|
* the process accounting system. |
|
*/ |
|
if (!check_free_space(acct)) |
|
goto out; |
|
|
|
fill_ac(&ac); |
|
/* we really need to bite the bullet and change layout */ |
|
ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid); |
|
ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid); |
|
#if ACCT_VERSION == 1 || ACCT_VERSION == 2 |
|
/* backward-compatible 16 bit fields */ |
|
ac.ac_uid16 = ac.ac_uid; |
|
ac.ac_gid16 = ac.ac_gid; |
|
#elif ACCT_VERSION == 3 |
|
{ |
|
struct pid_namespace *ns = acct->ns; |
|
|
|
ac.ac_pid = task_tgid_nr_ns(current, ns); |
|
rcu_read_lock(); |
|
ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), |
|
ns); |
|
rcu_read_unlock(); |
|
} |
|
#endif |
|
/* |
|
* Get freeze protection. If the fs is frozen, just skip the write |
|
* as we could deadlock the system otherwise. |
|
*/ |
|
if (file_start_write_trylock(file)) { |
|
/* it's been opened O_APPEND, so position is irrelevant */ |
|
loff_t pos = 0; |
|
__kernel_write(file, &ac, sizeof(acct_t), &pos); |
|
file_end_write(file); |
|
} |
|
out: |
|
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; |
|
revert_creds(orig_cred); |
|
} |
|
|
|
/** |
|
* acct_collect - collect accounting information into pacct_struct |
|
* @exitcode: task exit code |
|
* @group_dead: not 0, if this thread is the last one in the process. |
|
*/ |
|
void acct_collect(long exitcode, int group_dead) |
|
{ |
|
struct pacct_struct *pacct = ¤t->signal->pacct; |
|
u64 utime, stime; |
|
unsigned long vsize = 0; |
|
|
|
if (group_dead && current->mm) { |
|
struct vm_area_struct *vma; |
|
|
|
mmap_read_lock(current->mm); |
|
vma = current->mm->mmap; |
|
while (vma) { |
|
vsize += vma->vm_end - vma->vm_start; |
|
vma = vma->vm_next; |
|
} |
|
mmap_read_unlock(current->mm); |
|
} |
|
|
|
spin_lock_irq(¤t->sighand->siglock); |
|
if (group_dead) |
|
pacct->ac_mem = vsize / 1024; |
|
if (thread_group_leader(current)) { |
|
pacct->ac_exitcode = exitcode; |
|
if (current->flags & PF_FORKNOEXEC) |
|
pacct->ac_flag |= AFORK; |
|
} |
|
if (current->flags & PF_SUPERPRIV) |
|
pacct->ac_flag |= ASU; |
|
if (current->flags & PF_DUMPCORE) |
|
pacct->ac_flag |= ACORE; |
|
if (current->flags & PF_SIGNALED) |
|
pacct->ac_flag |= AXSIG; |
|
|
|
task_cputime(current, &utime, &stime); |
|
pacct->ac_utime += utime; |
|
pacct->ac_stime += stime; |
|
pacct->ac_minflt += current->min_flt; |
|
pacct->ac_majflt += current->maj_flt; |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
} |
|
|
|
static void slow_acct_process(struct pid_namespace *ns) |
|
{ |
|
for ( ; ns; ns = ns->parent) { |
|
struct bsd_acct_struct *acct = acct_get(ns); |
|
if (acct) { |
|
do_acct_process(acct); |
|
mutex_unlock(&acct->lock); |
|
acct_put(acct); |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* acct_process - handles process accounting for an exiting task |
|
*/ |
|
void acct_process(void) |
|
{ |
|
struct pid_namespace *ns; |
|
|
|
/* |
|
* This loop is safe lockless, since current is still |
|
* alive and holds its namespace, which in turn holds |
|
* its parent. |
|
*/ |
|
for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) { |
|
if (ns->bacct) |
|
break; |
|
} |
|
if (unlikely(ns)) |
|
slow_acct_process(ns); |
|
}
|
|
|