linux/fs/proc/array.c
Richard W.M. Jones 3e42979e65 procfs: expose umask in /proc/<PID>/status
It's not possible to read the process umask without also modifying it,
which is what umask(2) does.  A library cannot read umask safely,
especially if the main program might be multithreaded.

Add a new status line ("Umask") in /proc/<PID>/status.  It contains the
file mode creation mask (umask) in octal.  It is only shown for tasks
which have task->fs.

This patch is adapted from one originally written by Pierre Carrier.

The use case is that we have endless trouble with people setting weird
umask() values (usually on the grounds of "security"), and then
everything breaking.  I'm on the hook to fix these.  We'd like to add
debugging to our program so we can dump out the umask in debug reports.

Previous versions of the patch used a syscall so you could only read
your own umask.  That's all I need.  However there was quite a lot of
push-back from those, so this new version exports it in /proc.

See:
  https://lkml.org/lkml/2016/4/13/704 [umask2]
  https://lkml.org/lkml/2016/4/13/487 [getumask]

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pierre Carrier <pierre@spotify.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00

737 lines
19 KiB
C

/*
* linux/fs/proc/array.c
*
* Copyright (C) 1992 by Linus Torvalds
* based on ideas by Darren Senn
*
* Fixes:
* Michael. K. Johnson: stat,statm extensions.
* <johnsonm@stolaf.edu>
*
* Pauline Middelink : Made cmdline,envline only break at '\0's, to
* make sure SET_PROCTITLE works. Also removed
* bad '!' which forced address recalculation for
* EVERY character on the current page.
* <middelin@polyware.iaf.nl>
*
* Danny ter Haar : added cpuinfo
* <dth@cistron.nl>
*
* Alessandro Rubini : profile extension.
* <rubini@ipvvis.unipv.it>
*
* Jeff Tranter : added BogoMips field to cpuinfo
* <Jeff_Tranter@Mitel.COM>
*
* Bruno Haible : remove 4K limit for the maps file
* <haible@ma2s2.mathematik.uni-karlsruhe.de>
*
* Yves Arrouye : remove removal of trailing spaces in get_array.
* <Yves.Arrouye@marin.fdn.fr>
*
* Jerome Forissier : added per-CPU time information to /proc/stat
* and /proc/<pid>/cpu extension
* <forissier@isia.cma.fr>
* - Incorporation and non-SMP safe operation
* of forissier patch in 2.1.78 by
* Hans Marcus <crowbar@concepts.nl>
*
* aeb@cwi.nl : /proc/partitions
*
*
* Alan Cox : security fixes.
* <alan@lxorguk.ukuu.org.uk>
*
* Al Viro : safe handling of mm_struct
*
* Gerhard Wichert : added BIGMEM support
* Siemens AG <Gerhard.Wichert@pdb.siemens.de>
*
* Al Viro & Jeff Garzik : moved most of the thing into base.c and
* : proc_misc.c. The rest may eventually go into
* : base.c too.
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/tty.h>
#include <linux/string.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/signal.h>
#include <linux/highmem.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/times.h>
#include <linux/cpuset.h>
#include <linux/rcupdate.h>
#include <linux/delayacct.h>
#include <linux/seq_file.h>
#include <linux/pid_namespace.h>
#include <linux/ptrace.h>
#include <linux/tracehook.h>
#include <linux/string_helpers.h>
#include <linux/user_namespace.h>
#include <linux/fs_struct.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include "internal.h"
static inline void task_name(struct seq_file *m, struct task_struct *p)
{
char *buf;
size_t size;
char tcomm[sizeof(p->comm)];
int ret;
get_task_comm(tcomm, p);
seq_puts(m, "Name:\t");
size = seq_get_buf(m, &buf);
ret = string_escape_str(tcomm, buf, size, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
seq_commit(m, ret < size ? ret : -1);
seq_putc(m, '\n');
}
/*
* The task state array is a strange "bitmap" of
* reasons to sleep. Thus "running" is zero, and
* you can test for combinations of others with
* simple bit tests.
*/
static const char * const task_state_array[] = {
"R (running)", /* 0 */
"S (sleeping)", /* 1 */
"D (disk sleep)", /* 2 */
"T (stopped)", /* 4 */
"t (tracing stop)", /* 8 */
"X (dead)", /* 16 */
"Z (zombie)", /* 32 */
};
static inline const char *get_task_state(struct task_struct *tsk)
{
unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
/*
* Parked tasks do not run; they sit in __kthread_parkme().
* Without this check, we would report them as running, which is
* clearly wrong, so we report them as sleeping instead.
*/
if (tsk->state == TASK_PARKED)
state = TASK_INTERRUPTIBLE;
BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
return task_state_array[fls(state)];
}
static inline int get_task_umask(struct task_struct *tsk)
{
struct fs_struct *fs;
int umask = -ENOENT;
task_lock(tsk);
fs = tsk->fs;
if (fs)
umask = fs->umask;
task_unlock(tsk);
return umask;
}
static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *p)
{
struct user_namespace *user_ns = seq_user_ns(m);
struct group_info *group_info;
int g, umask;
struct task_struct *tracer;
const struct cred *cred;
pid_t ppid, tpid = 0, tgid, ngid;
unsigned int max_fds = 0;
rcu_read_lock();
ppid = pid_alive(p) ?
task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
tracer = ptrace_parent(p);
if (tracer)
tpid = task_pid_nr_ns(tracer, ns);
tgid = task_tgid_nr_ns(p, ns);
ngid = task_numa_group_id(p);
cred = get_task_cred(p);
umask = get_task_umask(p);
if (umask >= 0)
seq_printf(m, "Umask:\t%#04o\n", umask);
task_lock(p);
if (p->files)
max_fds = files_fdtable(p->files)->max_fds;
task_unlock(p);
rcu_read_unlock();
seq_printf(m,
"State:\t%s\n"
"Tgid:\t%d\n"
"Ngid:\t%d\n"
"Pid:\t%d\n"
"PPid:\t%d\n"
"TracerPid:\t%d\n"
"Uid:\t%d\t%d\t%d\t%d\n"
"Gid:\t%d\t%d\t%d\t%d\n"
"FDSize:\t%d\nGroups:\t",
get_task_state(p),
tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,
from_kuid_munged(user_ns, cred->uid),
from_kuid_munged(user_ns, cred->euid),
from_kuid_munged(user_ns, cred->suid),
from_kuid_munged(user_ns, cred->fsuid),
from_kgid_munged(user_ns, cred->gid),
from_kgid_munged(user_ns, cred->egid),
from_kgid_munged(user_ns, cred->sgid),
from_kgid_munged(user_ns, cred->fsgid),
max_fds);
group_info = cred->group_info;
for (g = 0; g < group_info->ngroups; g++)
seq_printf(m, "%d ",
from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
put_cred(cred);
#ifdef CONFIG_PID_NS
seq_puts(m, "\nNStgid:");
for (g = ns->level; g <= pid->level; g++)
seq_printf(m, "\t%d",
task_tgid_nr_ns(p, pid->numbers[g].ns));
seq_puts(m, "\nNSpid:");
for (g = ns->level; g <= pid->level; g++)
seq_printf(m, "\t%d",
task_pid_nr_ns(p, pid->numbers[g].ns));
seq_puts(m, "\nNSpgid:");
for (g = ns->level; g <= pid->level; g++)
seq_printf(m, "\t%d",
task_pgrp_nr_ns(p, pid->numbers[g].ns));
seq_puts(m, "\nNSsid:");
for (g = ns->level; g <= pid->level; g++)
seq_printf(m, "\t%d",
task_session_nr_ns(p, pid->numbers[g].ns));
#endif
seq_putc(m, '\n');
}
void render_sigset_t(struct seq_file *m, const char *header,
sigset_t *set)
{
int i;
seq_puts(m, header);
i = _NSIG;
do {
int x = 0;
i -= 4;
if (sigismember(set, i+1)) x |= 1;
if (sigismember(set, i+2)) x |= 2;
if (sigismember(set, i+3)) x |= 4;
if (sigismember(set, i+4)) x |= 8;
seq_printf(m, "%x", x);
} while (i >= 4);
seq_putc(m, '\n');
}
static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
sigset_t *catch)
{
struct k_sigaction *k;
int i;
k = p->sighand->action;
for (i = 1; i <= _NSIG; ++i, ++k) {
if (k->sa.sa_handler == SIG_IGN)
sigaddset(ign, i);
else if (k->sa.sa_handler != SIG_DFL)
sigaddset(catch, i);
}
}
static inline void task_sig(struct seq_file *m, struct task_struct *p)
{
unsigned long flags;
sigset_t pending, shpending, blocked, ignored, caught;
int num_threads = 0;
unsigned long qsize = 0;
unsigned long qlim = 0;
sigemptyset(&pending);
sigemptyset(&shpending);
sigemptyset(&blocked);
sigemptyset(&ignored);
sigemptyset(&caught);
if (lock_task_sighand(p, &flags)) {
pending = p->pending.signal;
shpending = p->signal->shared_pending.signal;
blocked = p->blocked;
collect_sigign_sigcatch(p, &ignored, &caught);
num_threads = get_nr_threads(p);
rcu_read_lock(); /* FIXME: is this correct? */
qsize = atomic_read(&__task_cred(p)->user->sigpending);
rcu_read_unlock();
qlim = task_rlimit(p, RLIMIT_SIGPENDING);
unlock_task_sighand(p, &flags);
}
seq_printf(m, "Threads:\t%d\n", num_threads);
seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim);
/* render them all */
render_sigset_t(m, "SigPnd:\t", &pending);
render_sigset_t(m, "ShdPnd:\t", &shpending);
render_sigset_t(m, "SigBlk:\t", &blocked);
render_sigset_t(m, "SigIgn:\t", &ignored);
render_sigset_t(m, "SigCgt:\t", &caught);
}
static void render_cap_t(struct seq_file *m, const char *header,
kernel_cap_t *a)
{
unsigned __capi;
seq_puts(m, header);
CAP_FOR_EACH_U32(__capi) {
seq_printf(m, "%08x",
a->cap[CAP_LAST_U32 - __capi]);
}
seq_putc(m, '\n');
}
static inline void task_cap(struct seq_file *m, struct task_struct *p)
{
const struct cred *cred;
kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
cap_bset, cap_ambient;
rcu_read_lock();
cred = __task_cred(p);
cap_inheritable = cred->cap_inheritable;
cap_permitted = cred->cap_permitted;
cap_effective = cred->cap_effective;
cap_bset = cred->cap_bset;
cap_ambient = cred->cap_ambient;
rcu_read_unlock();
render_cap_t(m, "CapInh:\t", &cap_inheritable);
render_cap_t(m, "CapPrm:\t", &cap_permitted);
render_cap_t(m, "CapEff:\t", &cap_effective);
render_cap_t(m, "CapBnd:\t", &cap_bset);
render_cap_t(m, "CapAmb:\t", &cap_ambient);
}
static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
{
#ifdef CONFIG_SECCOMP
seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode);
#endif
}
static inline void task_context_switch_counts(struct seq_file *m,
struct task_struct *p)
{
seq_printf(m, "voluntary_ctxt_switches:\t%lu\n"
"nonvoluntary_ctxt_switches:\t%lu\n",
p->nvcsw,
p->nivcsw);
}
static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
{
seq_printf(m, "Cpus_allowed:\t%*pb\n",
cpumask_pr_args(&task->cpus_allowed));
seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
cpumask_pr_args(&task->cpus_allowed));
}
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
struct mm_struct *mm = get_task_mm(task);
task_name(m, task);
task_state(m, ns, pid, task);
if (mm) {
task_mem(m, mm);
mmput(mm);
}
task_sig(m, task);
task_cap(m, task);
task_seccomp(m, task);
task_cpus_allowed(m, task);
cpuset_task_status_allowed(m, task);
task_context_switch_counts(m, task);
return 0;
}
static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task, int whole)
{
unsigned long vsize, eip, esp, wchan = 0;
int priority, nice;
int tty_pgrp = -1, tty_nr = 0;
sigset_t sigign, sigcatch;
char state;
pid_t ppid = 0, pgid = -1, sid = -1;
int num_threads = 0;
int permitted;
struct mm_struct *mm;
unsigned long long start_time;
unsigned long cmin_flt = 0, cmaj_flt = 0;
unsigned long min_flt = 0, maj_flt = 0;
cputime_t cutime, cstime, utime, stime;
cputime_t cgtime, gtime;
unsigned long rsslim = 0;
char tcomm[sizeof(task->comm)];
unsigned long flags;
state = *get_task_state(task);
vsize = eip = esp = 0;
permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
mm = get_task_mm(task);
if (mm) {
vsize = task_vsize(mm);
if (permitted) {
eip = KSTK_EIP(task);
esp = KSTK_ESP(task);
}
}
get_task_comm(tcomm, task);
sigemptyset(&sigign);
sigemptyset(&sigcatch);
cutime = cstime = utime = stime = 0;
cgtime = gtime = 0;
if (lock_task_sighand(task, &flags)) {
struct signal_struct *sig = task->signal;
if (sig->tty) {
struct pid *pgrp = tty_get_pgrp(sig->tty);
tty_pgrp = pid_nr_ns(pgrp, ns);
put_pid(pgrp);
tty_nr = new_encode_dev(tty_devnum(sig->tty));
}
num_threads = get_nr_threads(task);
collect_sigign_sigcatch(task, &sigign, &sigcatch);
cmin_flt = sig->cmin_flt;
cmaj_flt = sig->cmaj_flt;
cutime = sig->cutime;
cstime = sig->cstime;
cgtime = sig->cgtime;
rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
/* add up live thread stats at the group level */
if (whole) {
struct task_struct *t = task;
do {
min_flt += t->min_flt;
maj_flt += t->maj_flt;
gtime += task_gtime(t);
} while_each_thread(task, t);
min_flt += sig->min_flt;
maj_flt += sig->maj_flt;
thread_group_cputime_adjusted(task, &utime, &stime);
gtime += sig->gtime;
}
sid = task_session_nr_ns(task, ns);
ppid = task_tgid_nr_ns(task->real_parent, ns);
pgid = task_pgrp_nr_ns(task, ns);
unlock_task_sighand(task, &flags);
}
if (permitted && (!whole || num_threads < 2))
wchan = get_wchan(task);
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
task_cputime_adjusted(task, &utime, &stime);
gtime = task_gtime(task);
}
/* scale priority and nice values from timeslices to -20..20 */
/* to make it look like a "normal" Unix priority/nice value */
priority = task_prio(task);
nice = task_nice(task);
/* convert nsec -> ticks */
start_time = nsec_to_clock_t(task->real_start_time);
seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
seq_put_decimal_ll(m, ' ', ppid);
seq_put_decimal_ll(m, ' ', pgid);
seq_put_decimal_ll(m, ' ', sid);
seq_put_decimal_ll(m, ' ', tty_nr);
seq_put_decimal_ll(m, ' ', tty_pgrp);
seq_put_decimal_ull(m, ' ', task->flags);
seq_put_decimal_ull(m, ' ', min_flt);
seq_put_decimal_ull(m, ' ', cmin_flt);
seq_put_decimal_ull(m, ' ', maj_flt);
seq_put_decimal_ull(m, ' ', cmaj_flt);
seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
seq_put_decimal_ll(m, ' ', priority);
seq_put_decimal_ll(m, ' ', nice);
seq_put_decimal_ll(m, ' ', num_threads);
seq_put_decimal_ull(m, ' ', 0);
seq_put_decimal_ull(m, ' ', start_time);
seq_put_decimal_ull(m, ' ', vsize);
seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
seq_put_decimal_ull(m, ' ', rsslim);
seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
seq_put_decimal_ull(m, ' ', esp);
seq_put_decimal_ull(m, ' ', eip);
/* The signal information here is obsolete.
* It must be decimal for Linux 2.0 compatibility.
* Use /proc/#/status for real-time signals.
*/
seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
/*
* We used to output the absolute kernel address, but that's an
* information leak - so instead we show a 0/1 flag here, to signal
* to user-space whether there's a wchan field in /proc/PID/wchan.
*
* This works with older implementations of procps as well.
*/
if (wchan)
seq_puts(m, " 1");
else
seq_puts(m, " 0");
seq_put_decimal_ull(m, ' ', 0);
seq_put_decimal_ull(m, ' ', 0);
seq_put_decimal_ll(m, ' ', task->exit_signal);
seq_put_decimal_ll(m, ' ', task_cpu(task));
seq_put_decimal_ull(m, ' ', task->rt_priority);
seq_put_decimal_ull(m, ' ', task->policy);
seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
if (mm && permitted) {
seq_put_decimal_ull(m, ' ', mm->start_data);
seq_put_decimal_ull(m, ' ', mm->end_data);
seq_put_decimal_ull(m, ' ', mm->start_brk);
seq_put_decimal_ull(m, ' ', mm->arg_start);
seq_put_decimal_ull(m, ' ', mm->arg_end);
seq_put_decimal_ull(m, ' ', mm->env_start);
seq_put_decimal_ull(m, ' ', mm->env_end);
} else
seq_printf(m, " 0 0 0 0 0 0 0");
if (permitted)
seq_put_decimal_ll(m, ' ', task->exit_code);
else
seq_put_decimal_ll(m, ' ', 0);
seq_putc(m, '\n');
if (mm)
mmput(mm);
return 0;
}
int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
return do_task_stat(m, ns, pid, task, 0);
}
int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
return do_task_stat(m, ns, pid, task, 1);
}
int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
struct mm_struct *mm = get_task_mm(task);
if (mm) {
size = task_statm(mm, &shared, &text, &data, &resident);
mmput(mm);
}
/*
* For quick read, open code by putting numbers directly
* expected format is
* seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
* size, resident, shared, text, data);
*/
seq_put_decimal_ull(m, 0, size);
seq_put_decimal_ull(m, ' ', resident);
seq_put_decimal_ull(m, ' ', shared);
seq_put_decimal_ull(m, ' ', text);
seq_put_decimal_ull(m, ' ', 0);
seq_put_decimal_ull(m, ' ', data);
seq_put_decimal_ull(m, ' ', 0);
seq_putc(m, '\n');
return 0;
}
#ifdef CONFIG_PROC_CHILDREN
static struct pid *
get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
{
struct task_struct *start, *task;
struct pid *pid = NULL;
read_lock(&tasklist_lock);
start = pid_task(proc_pid(inode), PIDTYPE_PID);
if (!start)
goto out;
/*
* Lets try to continue searching first, this gives
* us significant speedup on children-rich processes.
*/
if (pid_prev) {
task = pid_task(pid_prev, PIDTYPE_PID);
if (task && task->real_parent == start &&
!(list_empty(&task->sibling))) {
if (list_is_last(&task->sibling, &start->children))
goto out;
task = list_first_entry(&task->sibling,
struct task_struct, sibling);
pid = get_pid(task_pid(task));
goto out;
}
}
/*
* Slow search case.
*
* We might miss some children here if children
* are exited while we were not holding the lock,
* but it was never promised to be accurate that
* much.
*
* "Just suppose that the parent sleeps, but N children
* exit after we printed their tids. Now the slow paths
* skips N extra children, we miss N tasks." (c)
*
* So one need to stop or freeze the leader and all
* its children to get a precise result.
*/
list_for_each_entry(task, &start->children, sibling) {
if (pos-- == 0) {
pid = get_pid(task_pid(task));
break;
}
}
out:
read_unlock(&tasklist_lock);
return pid;
}
static int children_seq_show(struct seq_file *seq, void *v)
{
struct inode *inode = seq->private;
pid_t pid;
pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
seq_printf(seq, "%d ", pid);
return 0;
}
static void *children_seq_start(struct seq_file *seq, loff_t *pos)
{
return get_children_pid(seq->private, NULL, *pos);
}
static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct pid *pid;
pid = get_children_pid(seq->private, v, *pos + 1);
put_pid(v);
++*pos;
return pid;
}
static void children_seq_stop(struct seq_file *seq, void *v)
{
put_pid(v);
}
static const struct seq_operations children_seq_ops = {
.start = children_seq_start,
.next = children_seq_next,
.stop = children_seq_stop,
.show = children_seq_show,
};
static int children_seq_open(struct inode *inode, struct file *file)
{
struct seq_file *m;
int ret;
ret = seq_open(file, &children_seq_ops);
if (ret)
return ret;
m = file->private_data;
m->private = inode;
return ret;
}
int children_seq_release(struct inode *inode, struct file *file)
{
seq_release(inode, file);
return 0;
}
const struct file_operations proc_tid_children_operations = {
.open = children_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = children_seq_release,
};
#endif /* CONFIG_PROC_CHILDREN */