array.c

Go to the documentation of this file.

/*
 *  linux/fs/proc/array.c
 *
 *  Copyright (C) 1992  by Linus Torvalds
 *  based on ideas by Darren Senn
 *
 * Fixes:
 * Michael. K. Johnson: stat,statm extensions.
 *                      <[email protected]>
 *
 * 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.
 *                      <[email protected]>
 *
 * Danny ter Haar    :  added cpuinfo
 *          <[email protected]>
 *
 * Alessandro Rubini :  profile extension.
 *                      <[email protected]>
 *
 * Jeff Tranter      :  added BogoMips field to cpuinfo
 *                      <[email protected]>
 *
 * Bruno Haible      :  remove 4K limit for the maps file
 *          <[email protected]>
 *
 * Yves Arrouye      :  remove removal of trailing spaces in get_array.
 *          <[email protected]>
 *
 * Jerome Forissier  :  added per-CPU time information to /proc/stat
 *                      and /proc/<pid>/cpu extension
 *                      <[email protected]>
 *          - Incorporation and non-SMP safe operation
 *          of forissier patch in 2.1.78 by
 *          Hans Marcus <[email protected]>
 *
 * [email protected]        :  /proc/partitions
 *
 *
 * Alan Cox      :  security fixes.
 *          <[email protected]>
 *
 * Al Viro           :  safe handling of mm_struct
 *
 * Gerhard Wichert   :  added BIGMEM support
 * Siemens AG           <[email protected]>
 *
 * 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/user_namespace.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)
{
    int i;
    char *buf, *end;
    char *name;
    char tcomm[sizeof(p->comm)];

    get_task_comm(tcomm, p);

    seq_puts(m, "Name:\t");
    end = m->buf + m->size;
    buf = m->buf + m->count;
    name = tcomm;
    i = sizeof(tcomm);
    while (i && (buf < end)) {
        unsigned char c = *name;
        name++;
        i--;
        *buf = c;
        if (!c)
            break;
        if (c == '\\') {
            buf++;
            if (buf < end)
                *buf++ = c;
            continue;
        }
        if (c == '\n') {
            *buf++ = '\\';
            if (buf < end)
                *buf++ = 'n';
            continue;
        }
        buf++;
    }
    m->count = buf - m->buf;
    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 */
    "Z (zombie)",       /*  16 */
    "X (dead)",     /*  32 */
    "x (dead)",     /*  64 */
    "K (wakekill)",     /* 128 */
    "W (waking)",       /* 256 */
};

static inline const char *get_task_state(struct task_struct *tsk)
{
    unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state;
    const char * const *p = &task_state_array[0];

    BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array));

    while (state) {
        p++;
        state >>= 1;
    }
    return *p;
}

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 = current_user_ns();
    struct group_info *group_info;
    int g;
    struct fdtable *fdt = NULL;
    const struct cred *cred;
    pid_t ppid, tpid;

    rcu_read_lock();
    ppid = pid_alive(p) ?
        task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
    tpid = 0;
    if (pid_alive(p)) {
        struct task_struct *tracer = ptrace_parent(p);
        if (tracer)
            tpid = task_pid_nr_ns(tracer, ns);
    }
    cred = get_task_cred(p);
    seq_printf(m,
        "State:\t%s\n"
        "Tgid:\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",
        get_task_state(p),
        task_tgid_nr_ns(p, ns),
        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));

    task_lock(p);
    if (p->files)
        fdt = files_fdtable(p->files);
    seq_printf(m,
        "FDSize:\t%d\n"
        "Groups:\t",
        fdt ? fdt->max_fds : 0);
    rcu_read_unlock();

    group_info = cred->group_info;
    task_unlock(p);

    for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
        seq_printf(m, "%d ",
               from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
    put_cred(cred);

    seq_putc(m, '\n');
}

static 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[(_KERNEL_CAPABILITY_U32S-1) - __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;

    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;
    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);
}

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_puts(m, "Cpus_allowed:\t");
    seq_cpumask(m, &task->cpus_allowed);
    seq_putc(m, '\n');
    seq_puts(m, "Cpus_allowed_list:\t");
    seq_cpumask_list(m, &task->cpus_allowed);
    seq_putc(m, '\n');
}

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_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 = ~0UL;
    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 | 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 += t->gtime;
                t = next_thread(t);
            } while (t != task);

            min_flt += sig->min_flt;
            maj_flt += sig->maj_flt;
            thread_group_times(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_times(task, &utime, &stime);
        gtime = task->gtime;
    }

    /* 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);

    /* Temporary variable needed for gcc-2.96 */
    /* convert timespec -> nsec*/
    start_time =
        (unsigned long long)task->real_start_time.tv_sec * NSEC_PER_SEC
                + task->real_start_time.tv_nsec;
    /* convert nsec -> ticks */
    start_time = nsec_to_clock_t(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);
    seq_put_decimal_ull(m, ' ', wchan);
    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_CHECKPOINT_RESTORE
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);
    return seq_printf(seq, "%d ", pid);
}

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_CHECKPOINT_RESTORE */