/*

* linux/fs/file.c

*

* Copyright (C) 1998-1999, Stephen Tweedie and Bill Hawes

*

* Manage the dynamic fd arrays in the process files_struct.

*/

#include <linux/export.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/mmzone.h>

#include <linux/time.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/file.h>

#include <linux/fdtable.h>

#include <linux/bitops.h>

#include <linux/interrupt.h>

#include <linux/spinlock.h>

#include <linux/rcupdate.h>

#include <linux/workqueue.h>

#include <linux/crc32c.h>

#include <linux/rtc.h>

struct fdtable_defer {

};

int sysctl_nr_open __read_mostly = 1024*1024;

int sysctl_nr_open_min = BITS_PER_LONG;

int sysctl_nr_open_max = 1024 * 1024;

static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);

static void *alloc_fdmem(size_t size)

{

if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {

void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);

if (data != NULL)

return data;

}

return vmalloc(size);

}

static void free_fdmem(void *ptr)

{

is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);

}

static void __free_fdtable(struct fdtable *fdt)

{

free_fdmem(fdt->fd);

free_fdmem(fdt->open_fds);

free_fdmem(fdt->user);

kfree(fdt);

}

static void free_fdtable_work(struct work_struct *work)

{

struct fdtable_defer *f =

container_of(work, struct fdtable_defer, wq);

struct fdtable *fdt;

spin_lock_bh(&f->lock);

fdt = f->next;

f->next = NULL;

spin_unlock_bh(&f->lock);

while(fdt) {

struct fdtable *next = fdt->next;

__free_fdtable(fdt);

fdt = next;

}

}

void free_fdtable_rcu(struct rcu_head *rcu)

{

struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);

struct fdtable_defer *fddef;

BUG_ON(!fdt);

if (fdt->max_fds <= NR_OPEN_DEFAULT) {

kmem_cache_free(files_cachep,

container_of(fdt, struct files_struct, fdtab));

return;

}

if (!is_vmalloc_addr(fdt->fd) && !is_vmalloc_addr(fdt->open_fds)

&& !is_vmalloc_addr(fdt->user)) {

kfree(fdt->fd);

kfree(fdt->open_fds);

kfree(fdt->user);

kfree(fdt);

} else {

fddef = &get_cpu_var(fdtable_defer_list);

spin_lock(&fddef->lock);

fdt->next = fddef->next;

fddef->next = fdt;

schedule_work(&fddef->wq);

spin_unlock(&fddef->lock);

put_cpu_var(fdtable_defer_list);

}

}

static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)

{

unsigned int cpy, set;

BUG_ON(nfdt->max_fds < ofdt->max_fds);

cpy = ofdt->max_fds * sizeof(struct file *);

set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);

memcpy(nfdt->fd, ofdt->fd, cpy);

memset((char *)(nfdt->fd) + cpy, 0, set);

cpy = ofdt->max_fds / BITS_PER_BYTE;

set = (nfdt->max_fds - ofdt->max_fds) / BITS_PER_BYTE;

memcpy(nfdt->open_fds, ofdt->open_fds, cpy);

memset((char *)(nfdt->open_fds) + cpy, 0, set);

memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);

memset((char *)(nfdt->close_on_exec) + cpy, 0, set);

memcpy(nfdt->user, ofdt->user,

ofdt->max_fds * sizeof(*nfdt->user));

memset(nfdt->user + ofdt->max_fds, 0,

(nfdt->max_fds - ofdt->max_fds) * sizeof(*nfdt->user));

}

static struct fdtable * alloc_fdtable(unsigned int nr)

{

struct fdtable *fdt;

void *data;

nr /= (1024 / sizeof(struct file *));

nr = roundup_pow_of_two(nr + 1);

nr *= (1024 / sizeof(struct file *));

if (unlikely(nr > sysctl_nr_open))

nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;

fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);

if (!fdt)

goto out;

fdt->max_fds = nr;

data = alloc_fdmem(nr * sizeof(struct file *));

if (!data)

goto out_fdt;

fdt->fd = data;

data = alloc_fdmem(max_t(size_t,

2 * nr / BITS_PER_BYTE, L1_CACHE_BYTES));

if (!data)

goto out_arr;

fdt->open_fds = data;

data += nr / BITS_PER_BYTE;

fdt->close_on_exec = data;

fdt->next = NULL;

data = alloc_fdmem(sizeof(*fdt->user) * nr);

if (!data)

goto out_open;

fdt->user = (struct fdt_user*) data;

return fdt;

out_open:

free_fdmem(fdt->open_fds);

out_arr:

free_fdmem(fdt->fd);

out_fdt:

kfree(fdt);

out:

return NULL;

}

static int expand_fdtable(struct files_struct *files, int nr)

__releases(files->file_lock)

__acquires(files->file_lock)

{

struct fdtable *new_fdt, *cur_fdt;

spin_unlock(&files->file_lock);

new_fdt = alloc_fdtable(nr);

spin_lock(&files->file_lock);

if (!new_fdt)

return -ENOMEM;

if (unlikely(new_fdt->max_fds <= nr)) {

__free_fdtable(new_fdt);

return -EMFILE;

}

cur_fdt = files_fdtable(files);

if (nr >= cur_fdt->max_fds) {

copy_fdtable(new_fdt, cur_fdt);

rcu_assign_pointer(files->fdt, new_fdt);

if (cur_fdt->max_fds > NR_OPEN_DEFAULT)

free_fdtable(cur_fdt);

} else {

__free_fdtable(new_fdt);

}

return 1;

}

int expand_files(struct files_struct *files, int nr)

{

struct fdtable *fdt;

fdt = files_fdtable(files);

if (nr >= rlimit(RLIMIT_NOFILE))

return -EMFILE;

if (nr < fdt->max_fds)

return 0;

if (nr >= sysctl_nr_open)

return -EMFILE;

return expand_fdtable(files, nr);

}

static int count_open_files(struct fdtable *fdt)

{

int size = fdt->max_fds;

int i;

for (i = size / BITS_PER_LONG; i > 0; ) {

if (fdt->open_fds[--i])

break;

}

i = (i + 1) * BITS_PER_LONG;

return i;

}

struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)

{

struct files_struct *newf;

struct file **old_fds, **new_fds;

int open_files, size, i;

struct fdtable *old_fdt, *new_fdt;

*errorp = -ENOMEM;

newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);

if (!newf)

goto out;

atomic_set(&newf->count, 1);

spin_lock_init(&newf->file_lock);

newf->next_fd = 0;

new_fdt = &newf->fdtab;

new_fdt->max_fds = NR_OPEN_DEFAULT;

new_fdt->close_on_exec = newf->close_on_exec_init;

new_fdt->open_fds = newf->open_fds_init;

new_fdt->fd = &newf->fd_array[0];

new_fdt->next = NULL;

new_fdt->user = &newf->user_array[0];

spin_lock(&oldf->file_lock);

old_fdt = files_fdtable(oldf);

open_files = count_open_files(old_fdt);

while (unlikely(open_files > new_fdt->max_fds)) {

spin_unlock(&oldf->file_lock);

if (new_fdt != &newf->fdtab)

__free_fdtable(new_fdt);

new_fdt = alloc_fdtable(open_files - 1);

if (!new_fdt) {

*errorp = -ENOMEM;

goto out_release;

}

if (unlikely(new_fdt->max_fds < open_files)) {

__free_fdtable(new_fdt);

*errorp = -EMFILE;

goto out_release;

}

spin_lock(&oldf->file_lock);

old_fdt = files_fdtable(oldf);

open_files = count_open_files(old_fdt);

}

old_fds = old_fdt->fd;

new_fds = new_fdt->fd;

memcpy(new_fdt->open_fds, old_fdt->open_fds, open_files / 8);

memcpy(new_fdt->close_on_exec, old_fdt->close_on_exec, open_files / 8);

memset(new_fdt->user, 0,

open_files * sizeof(*old_fdt->user));

for (i = open_files; i != 0; i--) {

struct file *f = *old_fds++;

if (f) {

get_file(f);

} else {

__clear_open_fd(open_files - i, new_fdt);

}

rcu_assign_pointer(*new_fds++, f);

}

spin_unlock(&oldf->file_lock);

size = (new_fdt->max_fds - open_files) * sizeof(struct file *);

memset(new_fds, 0, size);

if (new_fdt->max_fds > open_files) {

int left = (new_fdt->max_fds - open_files) / 8;

int start = open_files / BITS_PER_LONG;

memset(&new_fdt->open_fds[start], 0, left);

memset(&new_fdt->close_on_exec[start], 0, left);

memset(&new_fdt->user[open_files], 0,

(new_fdt->max_fds - open_files) * sizeof(*new_fdt->user));

}

rcu_assign_pointer(newf->fdt, new_fdt);

return newf;

out_release:

kmem_cache_free(files_cachep, newf);

out:

return NULL;

}

static void __devinit fdtable_defer_list_init(int cpu)

{

struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);

spin_lock_init(&fddef->lock);

INIT_WORK(&fddef->wq, free_fdtable_work);

fddef->next = NULL;

}

void __init files_defer_init(void)

{

int i;

for_each_possible_cpu(i)

fdtable_defer_list_init(i);

sysctl_nr_open_max = min((size_t)INT_MAX, ~(size_t)0/sizeof(void *)) &

-BITS_PER_LONG;

}

struct files_struct init_files = {

.count = ATOMIC_INIT(1),

.fdt = &init_files.fdtab,

.fdtab = {

.max_fds = NR_OPEN_DEFAULT,

.fd = &init_files.fd_array[0],

.close_on_exec = init_files.close_on_exec_init,

.open_fds = init_files.open_fds_init,

.user = &init_files.user_array[0],

},

.file_lock = __SPIN_LOCK_UNLOCKED(init_task.file_lock),

};

static void fdtable_usage_dump(struct fdtable *fdt)

{

int i;

char* buf;

struct timespec ts;

struct rtc_time tm;

buf = (char*) kmalloc(PATH_MAX, GFP_ATOMIC);

if (!buf) {

pr_err("%s: fail to alloc buffer\n", __func__);

return;

}

rcu_read_lock();

for (i = 0; i < fdt->max_fds; i++) {

struct file* file;

struct task_struct* user = NULL;

int pid;

char* path;

file = fdt->fd[i];

if (!file)

continue;

pid = fdt->user[i].installer;

ts = fdt->user[i].open_time;

rtc_time_to_tm(ts.tv_sec - (sys_tz.tz_minuteswest * 60), &tm);

user = find_task_by_vpid(pid);

if (user)

get_task_struct(user);

path = d_path(&file->f_path, buf, PATH_MAX);

if (IS_ERR(path))

path = "<unknown>";

else {

char* spath = strstr(path, ":[");

if (spath) spath[0] = '\0';

}

pr_warn("%d->fd[%d] file: %s, user: %d (%s %d:%d), (%02d-%02d %02d:%02d:%02d)\n",

current->tgid, i, path, pid,

user ? user->comm : "<unknown>",

user ? user->tgid : -1,

user ? user->pid : -1,

tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);

if (user)

put_task_struct(user);

}

rcu_read_unlock();

kfree(buf);

}

int alloc_fd(unsigned start, unsigned flags)

{

struct files_struct *files = current->files;

unsigned int fd;

int error;

struct fdtable *fdt;

spin_lock(&files->file_lock);

repeat:

fdt = files_fdtable(files);

fd = start;

if (fd < files->next_fd)

fd = files->next_fd;

if (fd < fdt->max_fds)

fd = find_next_zero_bit(fdt->open_fds, fdt->max_fds, fd);

error = expand_files(files, fd);

if (error < 0)

goto out;

if (error)

goto repeat;

if (start <= files->next_fd)

files->next_fd = fd + 1;

__set_open_fd(fd, fdt);

if (flags & O_CLOEXEC)

__set_close_on_exec(fd, fdt);

else

__clear_close_on_exec(fd, fdt);

memset(&fdt->user[fd], 0, sizeof(*fdt->user));

error = fd;

#if 1

if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {

printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);

rcu_assign_pointer(fdt->fd[fd], NULL);

}

#endif

out:

if (unlikely(error == -EMFILE)) {

static unsigned long debugging_ratelimit = 0;

const unsigned long debugging_delay_ms = 30000;

if (jiffies > debugging_ratelimit) {

debugging_ratelimit = jiffies + msecs_to_jiffies(debugging_delay_ms);

pr_warn("[%s] Too many open files (%d/%u), dump all fdt users:\n",

__func__, count_open_files(fdt), fdt->max_fds);

dump_stack();

fdtable_usage_dump(fdt);

pr_warn("[%s] end of dump\n", __func__);

}

}

spin_unlock(&files->file_lock);

return error;

}

EXPORT_SYMBOL(alloc_fd);

int get_unused_fd(void)

{

return alloc_fd(0, 0);

}

EXPORT_SYMBOL(get_unused_fd);